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v6.8
   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  Ptrace user space interface.
   4 *
   5 *    Copyright IBM Corp. 1999, 2010
   6 *    Author(s): Denis Joseph Barrow
   7 *               Martin Schwidefsky (schwidefsky@de.ibm.com)
   8 */
   9
  10#include "asm/ptrace.h"
  11#include <linux/kernel.h>
  12#include <linux/sched.h>
  13#include <linux/sched/task_stack.h>
  14#include <linux/mm.h>
  15#include <linux/smp.h>
  16#include <linux/errno.h>
  17#include <linux/ptrace.h>
  18#include <linux/user.h>
  19#include <linux/security.h>
  20#include <linux/audit.h>
  21#include <linux/signal.h>
  22#include <linux/elf.h>
  23#include <linux/regset.h>
  24#include <linux/seccomp.h>
  25#include <linux/compat.h>
  26#include <trace/syscall.h>
 
 
  27#include <asm/page.h>
  28#include <linux/uaccess.h>
  29#include <asm/unistd.h>
  30#include <asm/switch_to.h>
  31#include <asm/runtime_instr.h>
  32#include <asm/facility.h>
  33#include <asm/fpu/api.h>
  34
  35#include "entry.h"
  36
  37#ifdef CONFIG_COMPAT
  38#include "compat_ptrace.h"
  39#endif
  40
  41void update_cr_regs(struct task_struct *task)
  42{
  43	struct pt_regs *regs = task_pt_regs(task);
  44	struct thread_struct *thread = &task->thread;
  45	union ctlreg0 cr0_old, cr0_new;
  46	union ctlreg2 cr2_old, cr2_new;
  47	int cr0_changed, cr2_changed;
  48	union {
  49		struct ctlreg regs[3];
  50		struct {
  51			struct ctlreg control;
  52			struct ctlreg start;
  53			struct ctlreg end;
  54		};
  55	} old, new;
  56
  57	local_ctl_store(0, &cr0_old.reg);
  58	local_ctl_store(2, &cr2_old.reg);
  59	cr0_new = cr0_old;
  60	cr2_new = cr2_old;
  61	/* Take care of the enable/disable of transactional execution. */
  62	if (MACHINE_HAS_TE) {
  63		/* Set or clear transaction execution TXC bit 8. */
  64		cr0_new.tcx = 1;
  65		if (task->thread.per_flags & PER_FLAG_NO_TE)
  66			cr0_new.tcx = 0;
  67		/* Set or clear transaction execution TDC bits 62 and 63. */
  68		cr2_new.tdc = 0;
  69		if (task->thread.per_flags & PER_FLAG_TE_ABORT_RAND) {
  70			if (task->thread.per_flags & PER_FLAG_TE_ABORT_RAND_TEND)
  71				cr2_new.tdc = 1;
  72			else
  73				cr2_new.tdc = 2;
  74		}
  75	}
  76	/* Take care of enable/disable of guarded storage. */
  77	if (MACHINE_HAS_GS) {
  78		cr2_new.gse = 0;
  79		if (task->thread.gs_cb)
  80			cr2_new.gse = 1;
  81	}
  82	/* Load control register 0/2 iff changed */
  83	cr0_changed = cr0_new.val != cr0_old.val;
  84	cr2_changed = cr2_new.val != cr2_old.val;
  85	if (cr0_changed)
  86		local_ctl_load(0, &cr0_new.reg);
  87	if (cr2_changed)
  88		local_ctl_load(2, &cr2_new.reg);
  89	/* Copy user specified PER registers */
  90	new.control.val = thread->per_user.control;
  91	new.start.val = thread->per_user.start;
  92	new.end.val = thread->per_user.end;
  93
  94	/* merge TIF_SINGLE_STEP into user specified PER registers. */
  95	if (test_tsk_thread_flag(task, TIF_SINGLE_STEP) ||
  96	    test_tsk_thread_flag(task, TIF_UPROBE_SINGLESTEP)) {
  97		if (test_tsk_thread_flag(task, TIF_BLOCK_STEP))
  98			new.control.val |= PER_EVENT_BRANCH;
  99		else
 100			new.control.val |= PER_EVENT_IFETCH;
 101		new.control.val |= PER_CONTROL_SUSPENSION;
 102		new.control.val |= PER_EVENT_TRANSACTION_END;
 103		if (test_tsk_thread_flag(task, TIF_UPROBE_SINGLESTEP))
 104			new.control.val |= PER_EVENT_IFETCH;
 105		new.start.val = 0;
 106		new.end.val = -1UL;
 107	}
 108
 109	/* Take care of the PER enablement bit in the PSW. */
 110	if (!(new.control.val & PER_EVENT_MASK)) {
 111		regs->psw.mask &= ~PSW_MASK_PER;
 112		return;
 113	}
 114	regs->psw.mask |= PSW_MASK_PER;
 115	__local_ctl_store(9, 11, old.regs);
 116	if (memcmp(&new, &old, sizeof(struct per_regs)) != 0)
 117		__local_ctl_load(9, 11, new.regs);
 118}
 119
 120void user_enable_single_step(struct task_struct *task)
 121{
 122	clear_tsk_thread_flag(task, TIF_BLOCK_STEP);
 123	set_tsk_thread_flag(task, TIF_SINGLE_STEP);
 124}
 125
 126void user_disable_single_step(struct task_struct *task)
 127{
 128	clear_tsk_thread_flag(task, TIF_BLOCK_STEP);
 129	clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
 130}
 131
 132void user_enable_block_step(struct task_struct *task)
 133{
 134	set_tsk_thread_flag(task, TIF_SINGLE_STEP);
 135	set_tsk_thread_flag(task, TIF_BLOCK_STEP);
 136}
 137
 138/*
 139 * Called by kernel/ptrace.c when detaching..
 140 *
 141 * Clear all debugging related fields.
 142 */
 143void ptrace_disable(struct task_struct *task)
 144{
 145	memset(&task->thread.per_user, 0, sizeof(task->thread.per_user));
 146	memset(&task->thread.per_event, 0, sizeof(task->thread.per_event));
 147	clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
 148	clear_tsk_thread_flag(task, TIF_PER_TRAP);
 149	task->thread.per_flags = 0;
 150}
 151
 152#define __ADDR_MASK 7
 153
 154static inline unsigned long __peek_user_per(struct task_struct *child,
 155					    addr_t addr)
 156{
 157	if (addr == offsetof(struct per_struct_kernel, cr9))
 158		/* Control bits of the active per set. */
 159		return test_thread_flag(TIF_SINGLE_STEP) ?
 160			PER_EVENT_IFETCH : child->thread.per_user.control;
 161	else if (addr == offsetof(struct per_struct_kernel, cr10))
 162		/* Start address of the active per set. */
 163		return test_thread_flag(TIF_SINGLE_STEP) ?
 164			0 : child->thread.per_user.start;
 165	else if (addr == offsetof(struct per_struct_kernel, cr11))
 166		/* End address of the active per set. */
 167		return test_thread_flag(TIF_SINGLE_STEP) ?
 168			-1UL : child->thread.per_user.end;
 169	else if (addr == offsetof(struct per_struct_kernel, bits))
 170		/* Single-step bit. */
 171		return test_thread_flag(TIF_SINGLE_STEP) ?
 172			(1UL << (BITS_PER_LONG - 1)) : 0;
 173	else if (addr == offsetof(struct per_struct_kernel, starting_addr))
 174		/* Start address of the user specified per set. */
 175		return child->thread.per_user.start;
 176	else if (addr == offsetof(struct per_struct_kernel, ending_addr))
 177		/* End address of the user specified per set. */
 178		return child->thread.per_user.end;
 179	else if (addr == offsetof(struct per_struct_kernel, perc_atmid))
 180		/* PER code, ATMID and AI of the last PER trap */
 181		return (unsigned long)
 182			child->thread.per_event.cause << (BITS_PER_LONG - 16);
 183	else if (addr == offsetof(struct per_struct_kernel, address))
 184		/* Address of the last PER trap */
 185		return child->thread.per_event.address;
 186	else if (addr == offsetof(struct per_struct_kernel, access_id))
 187		/* Access id of the last PER trap */
 188		return (unsigned long)
 189			child->thread.per_event.paid << (BITS_PER_LONG - 8);
 190	return 0;
 191}
 192
 193/*
 194 * Read the word at offset addr from the user area of a process. The
 195 * trouble here is that the information is littered over different
 196 * locations. The process registers are found on the kernel stack,
 197 * the floating point stuff and the trace settings are stored in
 198 * the task structure. In addition the different structures in
 199 * struct user contain pad bytes that should be read as zeroes.
 200 * Lovely...
 201 */
 202static unsigned long __peek_user(struct task_struct *child, addr_t addr)
 203{
 204	addr_t offset, tmp;
 205
 206	if (addr < offsetof(struct user, regs.acrs)) {
 207		/*
 208		 * psw and gprs are stored on the stack
 209		 */
 210		tmp = *(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr);
 211		if (addr == offsetof(struct user, regs.psw.mask)) {
 212			/* Return a clean psw mask. */
 213			tmp &= PSW_MASK_USER | PSW_MASK_RI;
 214			tmp |= PSW_USER_BITS;
 215		}
 216
 217	} else if (addr < offsetof(struct user, regs.orig_gpr2)) {
 218		/*
 219		 * access registers are stored in the thread structure
 220		 */
 221		offset = addr - offsetof(struct user, regs.acrs);
 222		/*
 223		 * Very special case: old & broken 64 bit gdb reading
 224		 * from acrs[15]. Result is a 64 bit value. Read the
 225		 * 32 bit acrs[15] value and shift it by 32. Sick...
 226		 */
 227		if (addr == offsetof(struct user, regs.acrs[15]))
 228			tmp = ((unsigned long) child->thread.acrs[15]) << 32;
 229		else
 230			tmp = *(addr_t *)((addr_t) &child->thread.acrs + offset);
 231
 232	} else if (addr == offsetof(struct user, regs.orig_gpr2)) {
 233		/*
 234		 * orig_gpr2 is stored on the kernel stack
 235		 */
 236		tmp = (addr_t) task_pt_regs(child)->orig_gpr2;
 237
 238	} else if (addr < offsetof(struct user, regs.fp_regs)) {
 239		/*
 240		 * prevent reads of padding hole between
 241		 * orig_gpr2 and fp_regs on s390.
 242		 */
 243		tmp = 0;
 244
 245	} else if (addr == offsetof(struct user, regs.fp_regs.fpc)) {
 246		/*
 247		 * floating point control reg. is in the thread structure
 248		 */
 249		tmp = child->thread.fpu.fpc;
 250		tmp <<= BITS_PER_LONG - 32;
 251
 252	} else if (addr < offsetof(struct user, regs.fp_regs) + sizeof(s390_fp_regs)) {
 253		/*
 254		 * floating point regs. are either in child->thread.fpu
 255		 * or the child->thread.fpu.vxrs array
 256		 */
 257		offset = addr - offsetof(struct user, regs.fp_regs.fprs);
 258		if (cpu_has_vx())
 259			tmp = *(addr_t *)
 260			       ((addr_t) child->thread.fpu.vxrs + 2*offset);
 261		else
 262			tmp = *(addr_t *)
 263			       ((addr_t) child->thread.fpu.fprs + offset);
 264
 265	} else if (addr < offsetof(struct user, regs.per_info) + sizeof(per_struct)) {
 266		/*
 267		 * Handle access to the per_info structure.
 268		 */
 269		addr -= offsetof(struct user, regs.per_info);
 270		tmp = __peek_user_per(child, addr);
 271
 272	} else
 273		tmp = 0;
 274
 275	return tmp;
 276}
 277
 278static int
 279peek_user(struct task_struct *child, addr_t addr, addr_t data)
 280{
 281	addr_t tmp, mask;
 282
 283	/*
 284	 * Stupid gdb peeks/pokes the access registers in 64 bit with
 285	 * an alignment of 4. Programmers from hell...
 286	 */
 287	mask = __ADDR_MASK;
 288	if (addr >= offsetof(struct user, regs.acrs) &&
 289	    addr < offsetof(struct user, regs.orig_gpr2))
 290		mask = 3;
 291	if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
 292		return -EIO;
 293
 294	tmp = __peek_user(child, addr);
 295	return put_user(tmp, (addr_t __user *) data);
 296}
 297
 298static inline void __poke_user_per(struct task_struct *child,
 299				   addr_t addr, addr_t data)
 300{
 301	/*
 302	 * There are only three fields in the per_info struct that the
 303	 * debugger user can write to.
 304	 * 1) cr9: the debugger wants to set a new PER event mask
 305	 * 2) starting_addr: the debugger wants to set a new starting
 306	 *    address to use with the PER event mask.
 307	 * 3) ending_addr: the debugger wants to set a new ending
 308	 *    address to use with the PER event mask.
 309	 * The user specified PER event mask and the start and end
 310	 * addresses are used only if single stepping is not in effect.
 311	 * Writes to any other field in per_info are ignored.
 312	 */
 313	if (addr == offsetof(struct per_struct_kernel, cr9))
 314		/* PER event mask of the user specified per set. */
 315		child->thread.per_user.control =
 316			data & (PER_EVENT_MASK | PER_CONTROL_MASK);
 317	else if (addr == offsetof(struct per_struct_kernel, starting_addr))
 318		/* Starting address of the user specified per set. */
 319		child->thread.per_user.start = data;
 320	else if (addr == offsetof(struct per_struct_kernel, ending_addr))
 321		/* Ending address of the user specified per set. */
 322		child->thread.per_user.end = data;
 323}
 324
 325/*
 326 * Write a word to the user area of a process at location addr. This
 327 * operation does have an additional problem compared to peek_user.
 328 * Stores to the program status word and on the floating point
 329 * control register needs to get checked for validity.
 330 */
 331static int __poke_user(struct task_struct *child, addr_t addr, addr_t data)
 332{
 333	addr_t offset;
 334
 335
 336	if (addr < offsetof(struct user, regs.acrs)) {
 337		struct pt_regs *regs = task_pt_regs(child);
 338		/*
 339		 * psw and gprs are stored on the stack
 340		 */
 341		if (addr == offsetof(struct user, regs.psw.mask)) {
 342			unsigned long mask = PSW_MASK_USER;
 343
 344			mask |= is_ri_task(child) ? PSW_MASK_RI : 0;
 345			if ((data ^ PSW_USER_BITS) & ~mask)
 346				/* Invalid psw mask. */
 347				return -EINVAL;
 348			if ((data & PSW_MASK_ASC) == PSW_ASC_HOME)
 349				/* Invalid address-space-control bits */
 350				return -EINVAL;
 351			if ((data & PSW_MASK_EA) && !(data & PSW_MASK_BA))
 352				/* Invalid addressing mode bits */
 353				return -EINVAL;
 354		}
 355
 356		if (test_pt_regs_flag(regs, PIF_SYSCALL) &&
 357			addr == offsetof(struct user, regs.gprs[2])) {
 358			struct pt_regs *regs = task_pt_regs(child);
 359
 360			regs->int_code = 0x20000 | (data & 0xffff);
 361		}
 362		*(addr_t *)((addr_t) &regs->psw + addr) = data;
 363	} else if (addr < offsetof(struct user, regs.orig_gpr2)) {
 364		/*
 365		 * access registers are stored in the thread structure
 366		 */
 367		offset = addr - offsetof(struct user, regs.acrs);
 368		/*
 369		 * Very special case: old & broken 64 bit gdb writing
 370		 * to acrs[15] with a 64 bit value. Ignore the lower
 371		 * half of the value and write the upper 32 bit to
 372		 * acrs[15]. Sick...
 373		 */
 374		if (addr == offsetof(struct user, regs.acrs[15]))
 375			child->thread.acrs[15] = (unsigned int) (data >> 32);
 376		else
 377			*(addr_t *)((addr_t) &child->thread.acrs + offset) = data;
 378
 379	} else if (addr == offsetof(struct user, regs.orig_gpr2)) {
 380		/*
 381		 * orig_gpr2 is stored on the kernel stack
 382		 */
 383		task_pt_regs(child)->orig_gpr2 = data;
 384
 385	} else if (addr < offsetof(struct user, regs.fp_regs)) {
 386		/*
 387		 * prevent writes of padding hole between
 388		 * orig_gpr2 and fp_regs on s390.
 389		 */
 390		return 0;
 391
 392	} else if (addr == offsetof(struct user, regs.fp_regs.fpc)) {
 393		/*
 394		 * floating point control reg. is in the thread structure
 395		 */
 396		if ((unsigned int)data != 0)
 397			return -EINVAL;
 398		child->thread.fpu.fpc = data >> (BITS_PER_LONG - 32);
 399
 400	} else if (addr < offsetof(struct user, regs.fp_regs) + sizeof(s390_fp_regs)) {
 401		/*
 402		 * floating point regs. are either in child->thread.fpu
 403		 * or the child->thread.fpu.vxrs array
 404		 */
 405		offset = addr - offsetof(struct user, regs.fp_regs.fprs);
 406		if (cpu_has_vx())
 407			*(addr_t *)((addr_t)
 408				child->thread.fpu.vxrs + 2*offset) = data;
 409		else
 410			*(addr_t *)((addr_t)
 411				child->thread.fpu.fprs + offset) = data;
 412
 413	} else if (addr < offsetof(struct user, regs.per_info) + sizeof(per_struct)) {
 414		/*
 415		 * Handle access to the per_info structure.
 416		 */
 417		addr -= offsetof(struct user, regs.per_info);
 418		__poke_user_per(child, addr, data);
 419
 420	}
 421
 422	return 0;
 423}
 424
 425static int poke_user(struct task_struct *child, addr_t addr, addr_t data)
 426{
 427	addr_t mask;
 428
 429	/*
 430	 * Stupid gdb peeks/pokes the access registers in 64 bit with
 431	 * an alignment of 4. Programmers from hell indeed...
 432	 */
 433	mask = __ADDR_MASK;
 434	if (addr >= offsetof(struct user, regs.acrs) &&
 435	    addr < offsetof(struct user, regs.orig_gpr2))
 436		mask = 3;
 437	if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
 438		return -EIO;
 439
 440	return __poke_user(child, addr, data);
 441}
 442
 443long arch_ptrace(struct task_struct *child, long request,
 444		 unsigned long addr, unsigned long data)
 445{
 446	ptrace_area parea; 
 447	int copied, ret;
 448
 449	switch (request) {
 450	case PTRACE_PEEKUSR:
 451		/* read the word at location addr in the USER area. */
 452		return peek_user(child, addr, data);
 453
 454	case PTRACE_POKEUSR:
 455		/* write the word at location addr in the USER area */
 456		return poke_user(child, addr, data);
 457
 458	case PTRACE_PEEKUSR_AREA:
 459	case PTRACE_POKEUSR_AREA:
 460		if (copy_from_user(&parea, (void __force __user *) addr,
 461							sizeof(parea)))
 462			return -EFAULT;
 463		addr = parea.kernel_addr;
 464		data = parea.process_addr;
 465		copied = 0;
 466		while (copied < parea.len) {
 467			if (request == PTRACE_PEEKUSR_AREA)
 468				ret = peek_user(child, addr, data);
 469			else {
 470				addr_t utmp;
 471				if (get_user(utmp,
 472					     (addr_t __force __user *) data))
 473					return -EFAULT;
 474				ret = poke_user(child, addr, utmp);
 475			}
 476			if (ret)
 477				return ret;
 478			addr += sizeof(unsigned long);
 479			data += sizeof(unsigned long);
 480			copied += sizeof(unsigned long);
 481		}
 482		return 0;
 483	case PTRACE_GET_LAST_BREAK:
 484		return put_user(child->thread.last_break, (unsigned long __user *)data);
 485	case PTRACE_ENABLE_TE:
 486		if (!MACHINE_HAS_TE)
 487			return -EIO;
 488		child->thread.per_flags &= ~PER_FLAG_NO_TE;
 489		return 0;
 490	case PTRACE_DISABLE_TE:
 491		if (!MACHINE_HAS_TE)
 492			return -EIO;
 493		child->thread.per_flags |= PER_FLAG_NO_TE;
 494		child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND;
 495		return 0;
 496	case PTRACE_TE_ABORT_RAND:
 497		if (!MACHINE_HAS_TE || (child->thread.per_flags & PER_FLAG_NO_TE))
 498			return -EIO;
 499		switch (data) {
 500		case 0UL:
 501			child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND;
 502			break;
 503		case 1UL:
 504			child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND;
 505			child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND_TEND;
 506			break;
 507		case 2UL:
 508			child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND;
 509			child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND_TEND;
 510			break;
 511		default:
 512			return -EINVAL;
 513		}
 514		return 0;
 515	default:
 516		return ptrace_request(child, request, addr, data);
 517	}
 518}
 519
 520#ifdef CONFIG_COMPAT
 521/*
 522 * Now the fun part starts... a 31 bit program running in the
 523 * 31 bit emulation tracing another program. PTRACE_PEEKTEXT,
 524 * PTRACE_PEEKDATA, PTRACE_POKETEXT and PTRACE_POKEDATA are easy
 525 * to handle, the difference to the 64 bit versions of the requests
 526 * is that the access is done in multiples of 4 byte instead of
 527 * 8 bytes (sizeof(unsigned long) on 31/64 bit).
 528 * The ugly part are PTRACE_PEEKUSR, PTRACE_PEEKUSR_AREA,
 529 * PTRACE_POKEUSR and PTRACE_POKEUSR_AREA. If the traced program
 530 * is a 31 bit program too, the content of struct user can be
 531 * emulated. A 31 bit program peeking into the struct user of
 532 * a 64 bit program is a no-no.
 533 */
 534
 535/*
 536 * Same as peek_user_per but for a 31 bit program.
 537 */
 538static inline __u32 __peek_user_per_compat(struct task_struct *child,
 539					   addr_t addr)
 540{
 541	if (addr == offsetof(struct compat_per_struct_kernel, cr9))
 542		/* Control bits of the active per set. */
 543		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
 544			PER_EVENT_IFETCH : child->thread.per_user.control;
 545	else if (addr == offsetof(struct compat_per_struct_kernel, cr10))
 546		/* Start address of the active per set. */
 547		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
 548			0 : child->thread.per_user.start;
 549	else if (addr == offsetof(struct compat_per_struct_kernel, cr11))
 550		/* End address of the active per set. */
 551		return test_thread_flag(TIF_SINGLE_STEP) ?
 552			PSW32_ADDR_INSN : child->thread.per_user.end;
 553	else if (addr == offsetof(struct compat_per_struct_kernel, bits))
 554		/* Single-step bit. */
 555		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
 556			0x80000000 : 0;
 557	else if (addr == offsetof(struct compat_per_struct_kernel, starting_addr))
 558		/* Start address of the user specified per set. */
 559		return (__u32) child->thread.per_user.start;
 560	else if (addr == offsetof(struct compat_per_struct_kernel, ending_addr))
 561		/* End address of the user specified per set. */
 562		return (__u32) child->thread.per_user.end;
 563	else if (addr == offsetof(struct compat_per_struct_kernel, perc_atmid))
 564		/* PER code, ATMID and AI of the last PER trap */
 565		return (__u32) child->thread.per_event.cause << 16;
 566	else if (addr == offsetof(struct compat_per_struct_kernel, address))
 567		/* Address of the last PER trap */
 568		return (__u32) child->thread.per_event.address;
 569	else if (addr == offsetof(struct compat_per_struct_kernel, access_id))
 570		/* Access id of the last PER trap */
 571		return (__u32) child->thread.per_event.paid << 24;
 572	return 0;
 573}
 574
 575/*
 576 * Same as peek_user but for a 31 bit program.
 577 */
 578static u32 __peek_user_compat(struct task_struct *child, addr_t addr)
 579{
 580	addr_t offset;
 581	__u32 tmp;
 582
 583	if (addr < offsetof(struct compat_user, regs.acrs)) {
 584		struct pt_regs *regs = task_pt_regs(child);
 585		/*
 586		 * psw and gprs are stored on the stack
 587		 */
 588		if (addr == offsetof(struct compat_user, regs.psw.mask)) {
 589			/* Fake a 31 bit psw mask. */
 590			tmp = (__u32)(regs->psw.mask >> 32);
 591			tmp &= PSW32_MASK_USER | PSW32_MASK_RI;
 592			tmp |= PSW32_USER_BITS;
 593		} else if (addr == offsetof(struct compat_user, regs.psw.addr)) {
 594			/* Fake a 31 bit psw address. */
 595			tmp = (__u32) regs->psw.addr |
 596				(__u32)(regs->psw.mask & PSW_MASK_BA);
 597		} else {
 598			/* gpr 0-15 */
 599			tmp = *(__u32 *)((addr_t) &regs->psw + addr*2 + 4);
 600		}
 601	} else if (addr < offsetof(struct compat_user, regs.orig_gpr2)) {
 602		/*
 603		 * access registers are stored in the thread structure
 604		 */
 605		offset = addr - offsetof(struct compat_user, regs.acrs);
 606		tmp = *(__u32*)((addr_t) &child->thread.acrs + offset);
 607
 608	} else if (addr == offsetof(struct compat_user, regs.orig_gpr2)) {
 609		/*
 610		 * orig_gpr2 is stored on the kernel stack
 611		 */
 612		tmp = *(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4);
 613
 614	} else if (addr < offsetof(struct compat_user, regs.fp_regs)) {
 615		/*
 616		 * prevent reads of padding hole between
 617		 * orig_gpr2 and fp_regs on s390.
 618		 */
 619		tmp = 0;
 620
 621	} else if (addr == offsetof(struct compat_user, regs.fp_regs.fpc)) {
 622		/*
 623		 * floating point control reg. is in the thread structure
 624		 */
 625		tmp = child->thread.fpu.fpc;
 626
 627	} else if (addr < offsetof(struct compat_user, regs.fp_regs) + sizeof(s390_fp_regs)) {
 628		/*
 629		 * floating point regs. are either in child->thread.fpu
 630		 * or the child->thread.fpu.vxrs array
 631		 */
 632		offset = addr - offsetof(struct compat_user, regs.fp_regs.fprs);
 633		if (cpu_has_vx())
 634			tmp = *(__u32 *)
 635			       ((addr_t) child->thread.fpu.vxrs + 2*offset);
 636		else
 637			tmp = *(__u32 *)
 638			       ((addr_t) child->thread.fpu.fprs + offset);
 639
 640	} else if (addr < offsetof(struct compat_user, regs.per_info) + sizeof(struct compat_per_struct_kernel)) {
 641		/*
 642		 * Handle access to the per_info structure.
 643		 */
 644		addr -= offsetof(struct compat_user, regs.per_info);
 645		tmp = __peek_user_per_compat(child, addr);
 646
 647	} else
 648		tmp = 0;
 649
 650	return tmp;
 651}
 652
 653static int peek_user_compat(struct task_struct *child,
 654			    addr_t addr, addr_t data)
 655{
 656	__u32 tmp;
 657
 658	if (!is_compat_task() || (addr & 3) || addr > sizeof(struct user) - 3)
 659		return -EIO;
 660
 661	tmp = __peek_user_compat(child, addr);
 662	return put_user(tmp, (__u32 __user *) data);
 663}
 664
 665/*
 666 * Same as poke_user_per but for a 31 bit program.
 667 */
 668static inline void __poke_user_per_compat(struct task_struct *child,
 669					  addr_t addr, __u32 data)
 670{
 671	if (addr == offsetof(struct compat_per_struct_kernel, cr9))
 672		/* PER event mask of the user specified per set. */
 673		child->thread.per_user.control =
 674			data & (PER_EVENT_MASK | PER_CONTROL_MASK);
 675	else if (addr == offsetof(struct compat_per_struct_kernel, starting_addr))
 676		/* Starting address of the user specified per set. */
 677		child->thread.per_user.start = data;
 678	else if (addr == offsetof(struct compat_per_struct_kernel, ending_addr))
 679		/* Ending address of the user specified per set. */
 680		child->thread.per_user.end = data;
 681}
 682
 683/*
 684 * Same as poke_user but for a 31 bit program.
 685 */
 686static int __poke_user_compat(struct task_struct *child,
 687			      addr_t addr, addr_t data)
 688{
 689	__u32 tmp = (__u32) data;
 690	addr_t offset;
 691
 692	if (addr < offsetof(struct compat_user, regs.acrs)) {
 693		struct pt_regs *regs = task_pt_regs(child);
 694		/*
 695		 * psw, gprs, acrs and orig_gpr2 are stored on the stack
 696		 */
 697		if (addr == offsetof(struct compat_user, regs.psw.mask)) {
 698			__u32 mask = PSW32_MASK_USER;
 699
 700			mask |= is_ri_task(child) ? PSW32_MASK_RI : 0;
 701			/* Build a 64 bit psw mask from 31 bit mask. */
 702			if ((tmp ^ PSW32_USER_BITS) & ~mask)
 703				/* Invalid psw mask. */
 704				return -EINVAL;
 705			if ((data & PSW32_MASK_ASC) == PSW32_ASC_HOME)
 706				/* Invalid address-space-control bits */
 707				return -EINVAL;
 708			regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
 709				(regs->psw.mask & PSW_MASK_BA) |
 710				(__u64)(tmp & mask) << 32;
 711		} else if (addr == offsetof(struct compat_user, regs.psw.addr)) {
 712			/* Build a 64 bit psw address from 31 bit address. */
 713			regs->psw.addr = (__u64) tmp & PSW32_ADDR_INSN;
 714			/* Transfer 31 bit amode bit to psw mask. */
 715			regs->psw.mask = (regs->psw.mask & ~PSW_MASK_BA) |
 716				(__u64)(tmp & PSW32_ADDR_AMODE);
 717		} else {
 718			if (test_pt_regs_flag(regs, PIF_SYSCALL) &&
 719				addr == offsetof(struct compat_user, regs.gprs[2])) {
 720				struct pt_regs *regs = task_pt_regs(child);
 721
 722				regs->int_code = 0x20000 | (data & 0xffff);
 723			}
 724			/* gpr 0-15 */
 725			*(__u32*)((addr_t) &regs->psw + addr*2 + 4) = tmp;
 726		}
 727	} else if (addr < offsetof(struct compat_user, regs.orig_gpr2)) {
 728		/*
 729		 * access registers are stored in the thread structure
 730		 */
 731		offset = addr - offsetof(struct compat_user, regs.acrs);
 732		*(__u32*)((addr_t) &child->thread.acrs + offset) = tmp;
 733
 734	} else if (addr == offsetof(struct compat_user, regs.orig_gpr2)) {
 735		/*
 736		 * orig_gpr2 is stored on the kernel stack
 737		 */
 738		*(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4) = tmp;
 739
 740	} else if (addr < offsetof(struct compat_user, regs.fp_regs)) {
 741		/*
 742		 * prevent writess of padding hole between
 743		 * orig_gpr2 and fp_regs on s390.
 744		 */
 745		return 0;
 746
 747	} else if (addr == offsetof(struct compat_user, regs.fp_regs.fpc)) {
 748		/*
 749		 * floating point control reg. is in the thread structure
 750		 */
 751		child->thread.fpu.fpc = data;
 752
 753	} else if (addr < offsetof(struct compat_user, regs.fp_regs) + sizeof(s390_fp_regs)) {
 754		/*
 755		 * floating point regs. are either in child->thread.fpu
 756		 * or the child->thread.fpu.vxrs array
 757		 */
 758		offset = addr - offsetof(struct compat_user, regs.fp_regs.fprs);
 759		if (cpu_has_vx())
 760			*(__u32 *)((addr_t)
 761				child->thread.fpu.vxrs + 2*offset) = tmp;
 762		else
 763			*(__u32 *)((addr_t)
 764				child->thread.fpu.fprs + offset) = tmp;
 765
 766	} else if (addr < offsetof(struct compat_user, regs.per_info) + sizeof(struct compat_per_struct_kernel)) {
 767		/*
 768		 * Handle access to the per_info structure.
 769		 */
 770		addr -= offsetof(struct compat_user, regs.per_info);
 771		__poke_user_per_compat(child, addr, data);
 772	}
 773
 774	return 0;
 775}
 776
 777static int poke_user_compat(struct task_struct *child,
 778			    addr_t addr, addr_t data)
 779{
 780	if (!is_compat_task() || (addr & 3) ||
 781	    addr > sizeof(struct compat_user) - 3)
 782		return -EIO;
 783
 784	return __poke_user_compat(child, addr, data);
 785}
 786
 787long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 788			compat_ulong_t caddr, compat_ulong_t cdata)
 789{
 790	unsigned long addr = caddr;
 791	unsigned long data = cdata;
 792	compat_ptrace_area parea;
 793	int copied, ret;
 794
 795	switch (request) {
 796	case PTRACE_PEEKUSR:
 797		/* read the word at location addr in the USER area. */
 798		return peek_user_compat(child, addr, data);
 799
 800	case PTRACE_POKEUSR:
 801		/* write the word at location addr in the USER area */
 802		return poke_user_compat(child, addr, data);
 803
 804	case PTRACE_PEEKUSR_AREA:
 805	case PTRACE_POKEUSR_AREA:
 806		if (copy_from_user(&parea, (void __force __user *) addr,
 807							sizeof(parea)))
 808			return -EFAULT;
 809		addr = parea.kernel_addr;
 810		data = parea.process_addr;
 811		copied = 0;
 812		while (copied < parea.len) {
 813			if (request == PTRACE_PEEKUSR_AREA)
 814				ret = peek_user_compat(child, addr, data);
 815			else {
 816				__u32 utmp;
 817				if (get_user(utmp,
 818					     (__u32 __force __user *) data))
 819					return -EFAULT;
 820				ret = poke_user_compat(child, addr, utmp);
 821			}
 822			if (ret)
 823				return ret;
 824			addr += sizeof(unsigned int);
 825			data += sizeof(unsigned int);
 826			copied += sizeof(unsigned int);
 827		}
 828		return 0;
 829	case PTRACE_GET_LAST_BREAK:
 830		return put_user(child->thread.last_break, (unsigned int __user *)data);
 831	}
 832	return compat_ptrace_request(child, request, addr, data);
 833}
 834#endif
 835
 836/*
 837 * user_regset definitions.
 838 */
 839
 840static int s390_regs_get(struct task_struct *target,
 841			 const struct user_regset *regset,
 842			 struct membuf to)
 843{
 844	unsigned pos;
 845	if (target == current)
 846		save_access_regs(target->thread.acrs);
 847
 848	for (pos = 0; pos < sizeof(s390_regs); pos += sizeof(long))
 849		membuf_store(&to, __peek_user(target, pos));
 850	return 0;
 851}
 852
 853static int s390_regs_set(struct task_struct *target,
 854			 const struct user_regset *regset,
 855			 unsigned int pos, unsigned int count,
 856			 const void *kbuf, const void __user *ubuf)
 857{
 858	int rc = 0;
 859
 860	if (target == current)
 861		save_access_regs(target->thread.acrs);
 862
 863	if (kbuf) {
 864		const unsigned long *k = kbuf;
 865		while (count > 0 && !rc) {
 866			rc = __poke_user(target, pos, *k++);
 867			count -= sizeof(*k);
 868			pos += sizeof(*k);
 869		}
 870	} else {
 871		const unsigned long  __user *u = ubuf;
 872		while (count > 0 && !rc) {
 873			unsigned long word;
 874			rc = __get_user(word, u++);
 875			if (rc)
 876				break;
 877			rc = __poke_user(target, pos, word);
 878			count -= sizeof(*u);
 879			pos += sizeof(*u);
 880		}
 881	}
 882
 883	if (rc == 0 && target == current)
 884		restore_access_regs(target->thread.acrs);
 885
 886	return rc;
 887}
 888
 889static int s390_fpregs_get(struct task_struct *target,
 890			   const struct user_regset *regset,
 891			   struct membuf to)
 892{
 893	_s390_fp_regs fp_regs;
 894
 895	if (target == current)
 896		save_fpu_regs();
 897
 898	fp_regs.fpc = target->thread.fpu.fpc;
 899	fpregs_store(&fp_regs, &target->thread.fpu);
 900
 901	return membuf_write(&to, &fp_regs, sizeof(fp_regs));
 902}
 903
 904static int s390_fpregs_set(struct task_struct *target,
 905			   const struct user_regset *regset, unsigned int pos,
 906			   unsigned int count, const void *kbuf,
 907			   const void __user *ubuf)
 908{
 909	int rc = 0;
 910	freg_t fprs[__NUM_FPRS];
 911
 912	if (target == current)
 913		save_fpu_regs();
 914
 915	if (cpu_has_vx())
 916		convert_vx_to_fp(fprs, target->thread.fpu.vxrs);
 917	else
 918		memcpy(&fprs, target->thread.fpu.fprs, sizeof(fprs));
 919
 920	if (count > 0 && pos < offsetof(s390_fp_regs, fprs)) {
 921		u32 ufpc[2] = { target->thread.fpu.fpc, 0 };
 922		rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ufpc,
 923					0, offsetof(s390_fp_regs, fprs));
 924		if (rc)
 925			return rc;
 926		if (ufpc[1] != 0)
 927			return -EINVAL;
 928		target->thread.fpu.fpc = ufpc[0];
 929	}
 930
 931	if (rc == 0 && count > 0)
 932		rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 933					fprs, offsetof(s390_fp_regs, fprs), -1);
 934	if (rc)
 935		return rc;
 936
 937	if (cpu_has_vx())
 938		convert_fp_to_vx(target->thread.fpu.vxrs, fprs);
 939	else
 940		memcpy(target->thread.fpu.fprs, &fprs, sizeof(fprs));
 941
 942	return rc;
 943}
 944
 945static int s390_last_break_get(struct task_struct *target,
 946			       const struct user_regset *regset,
 947			       struct membuf to)
 948{
 949	return membuf_store(&to, target->thread.last_break);
 950}
 951
 952static int s390_last_break_set(struct task_struct *target,
 953			       const struct user_regset *regset,
 954			       unsigned int pos, unsigned int count,
 955			       const void *kbuf, const void __user *ubuf)
 956{
 957	return 0;
 958}
 959
 960static int s390_tdb_get(struct task_struct *target,
 961			const struct user_regset *regset,
 962			struct membuf to)
 963{
 964	struct pt_regs *regs = task_pt_regs(target);
 965	size_t size;
 966
 967	if (!(regs->int_code & 0x200))
 968		return -ENODATA;
 969	size = sizeof(target->thread.trap_tdb.data);
 970	return membuf_write(&to, target->thread.trap_tdb.data, size);
 971}
 972
 973static int s390_tdb_set(struct task_struct *target,
 974			const struct user_regset *regset,
 975			unsigned int pos, unsigned int count,
 976			const void *kbuf, const void __user *ubuf)
 977{
 978	return 0;
 979}
 980
 981static int s390_vxrs_low_get(struct task_struct *target,
 982			     const struct user_regset *regset,
 983			     struct membuf to)
 984{
 985	__u64 vxrs[__NUM_VXRS_LOW];
 986	int i;
 987
 988	if (!cpu_has_vx())
 989		return -ENODEV;
 990	if (target == current)
 991		save_fpu_regs();
 992	for (i = 0; i < __NUM_VXRS_LOW; i++)
 993		vxrs[i] = target->thread.fpu.vxrs[i].low;
 994	return membuf_write(&to, vxrs, sizeof(vxrs));
 995}
 996
 997static int s390_vxrs_low_set(struct task_struct *target,
 998			     const struct user_regset *regset,
 999			     unsigned int pos, unsigned int count,
1000			     const void *kbuf, const void __user *ubuf)
1001{
1002	__u64 vxrs[__NUM_VXRS_LOW];
1003	int i, rc;
1004
1005	if (!cpu_has_vx())
1006		return -ENODEV;
1007	if (target == current)
1008		save_fpu_regs();
1009
1010	for (i = 0; i < __NUM_VXRS_LOW; i++)
1011		vxrs[i] = target->thread.fpu.vxrs[i].low;
1012
1013	rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, vxrs, 0, -1);
1014	if (rc == 0)
1015		for (i = 0; i < __NUM_VXRS_LOW; i++)
1016			target->thread.fpu.vxrs[i].low = vxrs[i];
1017
1018	return rc;
1019}
1020
1021static int s390_vxrs_high_get(struct task_struct *target,
1022			      const struct user_regset *regset,
1023			      struct membuf to)
1024{
1025	if (!cpu_has_vx())
1026		return -ENODEV;
1027	if (target == current)
1028		save_fpu_regs();
1029	return membuf_write(&to, target->thread.fpu.vxrs + __NUM_VXRS_LOW,
1030			    __NUM_VXRS_HIGH * sizeof(__vector128));
1031}
1032
1033static int s390_vxrs_high_set(struct task_struct *target,
1034			      const struct user_regset *regset,
1035			      unsigned int pos, unsigned int count,
1036			      const void *kbuf, const void __user *ubuf)
1037{
1038	int rc;
1039
1040	if (!cpu_has_vx())
1041		return -ENODEV;
1042	if (target == current)
1043		save_fpu_regs();
1044
1045	rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
1046				target->thread.fpu.vxrs + __NUM_VXRS_LOW, 0, -1);
1047	return rc;
1048}
1049
1050static int s390_system_call_get(struct task_struct *target,
1051				const struct user_regset *regset,
1052				struct membuf to)
1053{
1054	return membuf_store(&to, target->thread.system_call);
1055}
1056
1057static int s390_system_call_set(struct task_struct *target,
1058				const struct user_regset *regset,
1059				unsigned int pos, unsigned int count,
1060				const void *kbuf, const void __user *ubuf)
1061{
1062	unsigned int *data = &target->thread.system_call;
1063	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
1064				  data, 0, sizeof(unsigned int));
1065}
1066
1067static int s390_gs_cb_get(struct task_struct *target,
1068			  const struct user_regset *regset,
1069			  struct membuf to)
1070{
1071	struct gs_cb *data = target->thread.gs_cb;
1072
1073	if (!MACHINE_HAS_GS)
1074		return -ENODEV;
1075	if (!data)
1076		return -ENODATA;
1077	if (target == current)
1078		save_gs_cb(data);
1079	return membuf_write(&to, data, sizeof(struct gs_cb));
1080}
1081
1082static int s390_gs_cb_set(struct task_struct *target,
1083			  const struct user_regset *regset,
1084			  unsigned int pos, unsigned int count,
1085			  const void *kbuf, const void __user *ubuf)
1086{
1087	struct gs_cb gs_cb = { }, *data = NULL;
1088	int rc;
1089
1090	if (!MACHINE_HAS_GS)
1091		return -ENODEV;
1092	if (!target->thread.gs_cb) {
1093		data = kzalloc(sizeof(*data), GFP_KERNEL);
1094		if (!data)
1095			return -ENOMEM;
1096	}
1097	if (!target->thread.gs_cb)
1098		gs_cb.gsd = 25;
1099	else if (target == current)
1100		save_gs_cb(&gs_cb);
1101	else
1102		gs_cb = *target->thread.gs_cb;
1103	rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
1104				&gs_cb, 0, sizeof(gs_cb));
1105	if (rc) {
1106		kfree(data);
1107		return -EFAULT;
1108	}
1109	preempt_disable();
1110	if (!target->thread.gs_cb)
1111		target->thread.gs_cb = data;
1112	*target->thread.gs_cb = gs_cb;
1113	if (target == current) {
1114		local_ctl_set_bit(2, CR2_GUARDED_STORAGE_BIT);
1115		restore_gs_cb(target->thread.gs_cb);
1116	}
1117	preempt_enable();
1118	return rc;
1119}
1120
1121static int s390_gs_bc_get(struct task_struct *target,
1122			  const struct user_regset *regset,
1123			  struct membuf to)
1124{
1125	struct gs_cb *data = target->thread.gs_bc_cb;
1126
1127	if (!MACHINE_HAS_GS)
1128		return -ENODEV;
1129	if (!data)
1130		return -ENODATA;
1131	return membuf_write(&to, data, sizeof(struct gs_cb));
1132}
1133
1134static int s390_gs_bc_set(struct task_struct *target,
1135			  const struct user_regset *regset,
1136			  unsigned int pos, unsigned int count,
1137			  const void *kbuf, const void __user *ubuf)
1138{
1139	struct gs_cb *data = target->thread.gs_bc_cb;
1140
1141	if (!MACHINE_HAS_GS)
1142		return -ENODEV;
1143	if (!data) {
1144		data = kzalloc(sizeof(*data), GFP_KERNEL);
1145		if (!data)
1146			return -ENOMEM;
1147		target->thread.gs_bc_cb = data;
1148	}
1149	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
1150				  data, 0, sizeof(struct gs_cb));
1151}
1152
1153static bool is_ri_cb_valid(struct runtime_instr_cb *cb)
1154{
1155	return (cb->rca & 0x1f) == 0 &&
1156		(cb->roa & 0xfff) == 0 &&
1157		(cb->rla & 0xfff) == 0xfff &&
1158		cb->s == 1 &&
1159		cb->k == 1 &&
1160		cb->h == 0 &&
1161		cb->reserved1 == 0 &&
1162		cb->ps == 1 &&
1163		cb->qs == 0 &&
1164		cb->pc == 1 &&
1165		cb->qc == 0 &&
1166		cb->reserved2 == 0 &&
1167		cb->reserved3 == 0 &&
1168		cb->reserved4 == 0 &&
1169		cb->reserved5 == 0 &&
1170		cb->reserved6 == 0 &&
1171		cb->reserved7 == 0 &&
1172		cb->reserved8 == 0 &&
1173		cb->rla >= cb->roa &&
1174		cb->rca >= cb->roa &&
1175		cb->rca <= cb->rla+1 &&
1176		cb->m < 3;
1177}
1178
1179static int s390_runtime_instr_get(struct task_struct *target,
1180				const struct user_regset *regset,
1181				struct membuf to)
1182{
1183	struct runtime_instr_cb *data = target->thread.ri_cb;
1184
1185	if (!test_facility(64))
1186		return -ENODEV;
1187	if (!data)
1188		return -ENODATA;
1189
1190	return membuf_write(&to, data, sizeof(struct runtime_instr_cb));
1191}
1192
1193static int s390_runtime_instr_set(struct task_struct *target,
1194				  const struct user_regset *regset,
1195				  unsigned int pos, unsigned int count,
1196				  const void *kbuf, const void __user *ubuf)
1197{
1198	struct runtime_instr_cb ri_cb = { }, *data = NULL;
1199	int rc;
1200
1201	if (!test_facility(64))
1202		return -ENODEV;
1203
1204	if (!target->thread.ri_cb) {
1205		data = kzalloc(sizeof(*data), GFP_KERNEL);
1206		if (!data)
1207			return -ENOMEM;
1208	}
1209
1210	if (target->thread.ri_cb) {
1211		if (target == current)
1212			store_runtime_instr_cb(&ri_cb);
1213		else
1214			ri_cb = *target->thread.ri_cb;
1215	}
1216
1217	rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
1218				&ri_cb, 0, sizeof(struct runtime_instr_cb));
1219	if (rc) {
1220		kfree(data);
1221		return -EFAULT;
1222	}
1223
1224	if (!is_ri_cb_valid(&ri_cb)) {
1225		kfree(data);
1226		return -EINVAL;
1227	}
1228	/*
1229	 * Override access key in any case, since user space should
1230	 * not be able to set it, nor should it care about it.
1231	 */
1232	ri_cb.key = PAGE_DEFAULT_KEY >> 4;
1233	preempt_disable();
1234	if (!target->thread.ri_cb)
1235		target->thread.ri_cb = data;
1236	*target->thread.ri_cb = ri_cb;
1237	if (target == current)
1238		load_runtime_instr_cb(target->thread.ri_cb);
1239	preempt_enable();
1240
1241	return 0;
1242}
1243
1244static const struct user_regset s390_regsets[] = {
1245	{
1246		.core_note_type = NT_PRSTATUS,
1247		.n = sizeof(s390_regs) / sizeof(long),
1248		.size = sizeof(long),
1249		.align = sizeof(long),
1250		.regset_get = s390_regs_get,
1251		.set = s390_regs_set,
1252	},
1253	{
1254		.core_note_type = NT_PRFPREG,
1255		.n = sizeof(s390_fp_regs) / sizeof(long),
1256		.size = sizeof(long),
1257		.align = sizeof(long),
1258		.regset_get = s390_fpregs_get,
1259		.set = s390_fpregs_set,
1260	},
1261	{
1262		.core_note_type = NT_S390_SYSTEM_CALL,
1263		.n = 1,
1264		.size = sizeof(unsigned int),
1265		.align = sizeof(unsigned int),
1266		.regset_get = s390_system_call_get,
1267		.set = s390_system_call_set,
1268	},
1269	{
1270		.core_note_type = NT_S390_LAST_BREAK,
1271		.n = 1,
1272		.size = sizeof(long),
1273		.align = sizeof(long),
1274		.regset_get = s390_last_break_get,
1275		.set = s390_last_break_set,
1276	},
1277	{
1278		.core_note_type = NT_S390_TDB,
1279		.n = 1,
1280		.size = 256,
1281		.align = 1,
1282		.regset_get = s390_tdb_get,
1283		.set = s390_tdb_set,
1284	},
1285	{
1286		.core_note_type = NT_S390_VXRS_LOW,
1287		.n = __NUM_VXRS_LOW,
1288		.size = sizeof(__u64),
1289		.align = sizeof(__u64),
1290		.regset_get = s390_vxrs_low_get,
1291		.set = s390_vxrs_low_set,
1292	},
1293	{
1294		.core_note_type = NT_S390_VXRS_HIGH,
1295		.n = __NUM_VXRS_HIGH,
1296		.size = sizeof(__vector128),
1297		.align = sizeof(__vector128),
1298		.regset_get = s390_vxrs_high_get,
1299		.set = s390_vxrs_high_set,
1300	},
1301	{
1302		.core_note_type = NT_S390_GS_CB,
1303		.n = sizeof(struct gs_cb) / sizeof(__u64),
1304		.size = sizeof(__u64),
1305		.align = sizeof(__u64),
1306		.regset_get = s390_gs_cb_get,
1307		.set = s390_gs_cb_set,
1308	},
1309	{
1310		.core_note_type = NT_S390_GS_BC,
1311		.n = sizeof(struct gs_cb) / sizeof(__u64),
1312		.size = sizeof(__u64),
1313		.align = sizeof(__u64),
1314		.regset_get = s390_gs_bc_get,
1315		.set = s390_gs_bc_set,
1316	},
1317	{
1318		.core_note_type = NT_S390_RI_CB,
1319		.n = sizeof(struct runtime_instr_cb) / sizeof(__u64),
1320		.size = sizeof(__u64),
1321		.align = sizeof(__u64),
1322		.regset_get = s390_runtime_instr_get,
1323		.set = s390_runtime_instr_set,
1324	},
1325};
1326
1327static const struct user_regset_view user_s390_view = {
1328	.name = "s390x",
1329	.e_machine = EM_S390,
1330	.regsets = s390_regsets,
1331	.n = ARRAY_SIZE(s390_regsets)
1332};
1333
1334#ifdef CONFIG_COMPAT
1335static int s390_compat_regs_get(struct task_struct *target,
1336				const struct user_regset *regset,
1337				struct membuf to)
1338{
1339	unsigned n;
1340
1341	if (target == current)
1342		save_access_regs(target->thread.acrs);
1343
1344	for (n = 0; n < sizeof(s390_compat_regs); n += sizeof(compat_ulong_t))
1345		membuf_store(&to, __peek_user_compat(target, n));
1346	return 0;
1347}
1348
1349static int s390_compat_regs_set(struct task_struct *target,
1350				const struct user_regset *regset,
1351				unsigned int pos, unsigned int count,
1352				const void *kbuf, const void __user *ubuf)
1353{
1354	int rc = 0;
1355
1356	if (target == current)
1357		save_access_regs(target->thread.acrs);
1358
1359	if (kbuf) {
1360		const compat_ulong_t *k = kbuf;
1361		while (count > 0 && !rc) {
1362			rc = __poke_user_compat(target, pos, *k++);
1363			count -= sizeof(*k);
1364			pos += sizeof(*k);
1365		}
1366	} else {
1367		const compat_ulong_t  __user *u = ubuf;
1368		while (count > 0 && !rc) {
1369			compat_ulong_t word;
1370			rc = __get_user(word, u++);
1371			if (rc)
1372				break;
1373			rc = __poke_user_compat(target, pos, word);
1374			count -= sizeof(*u);
1375			pos += sizeof(*u);
1376		}
1377	}
1378
1379	if (rc == 0 && target == current)
1380		restore_access_regs(target->thread.acrs);
1381
1382	return rc;
1383}
1384
1385static int s390_compat_regs_high_get(struct task_struct *target,
1386				     const struct user_regset *regset,
1387				     struct membuf to)
1388{
1389	compat_ulong_t *gprs_high;
1390	int i;
1391
1392	gprs_high = (compat_ulong_t *)task_pt_regs(target)->gprs;
1393	for (i = 0; i < NUM_GPRS; i++, gprs_high += 2)
1394		membuf_store(&to, *gprs_high);
1395	return 0;
1396}
1397
1398static int s390_compat_regs_high_set(struct task_struct *target,
1399				     const struct user_regset *regset,
1400				     unsigned int pos, unsigned int count,
1401				     const void *kbuf, const void __user *ubuf)
1402{
1403	compat_ulong_t *gprs_high;
1404	int rc = 0;
1405
1406	gprs_high = (compat_ulong_t *)
1407		&task_pt_regs(target)->gprs[pos / sizeof(compat_ulong_t)];
1408	if (kbuf) {
1409		const compat_ulong_t *k = kbuf;
1410		while (count > 0) {
1411			*gprs_high = *k++;
1412			*gprs_high += 2;
1413			count -= sizeof(*k);
1414		}
1415	} else {
1416		const compat_ulong_t  __user *u = ubuf;
1417		while (count > 0 && !rc) {
1418			unsigned long word;
1419			rc = __get_user(word, u++);
1420			if (rc)
1421				break;
1422			*gprs_high = word;
1423			*gprs_high += 2;
1424			count -= sizeof(*u);
1425		}
1426	}
1427
1428	return rc;
1429}
1430
1431static int s390_compat_last_break_get(struct task_struct *target,
1432				      const struct user_regset *regset,
1433				      struct membuf to)
1434{
1435	compat_ulong_t last_break = target->thread.last_break;
1436
1437	return membuf_store(&to, (unsigned long)last_break);
1438}
1439
1440static int s390_compat_last_break_set(struct task_struct *target,
1441				      const struct user_regset *regset,
1442				      unsigned int pos, unsigned int count,
1443				      const void *kbuf, const void __user *ubuf)
1444{
1445	return 0;
1446}
1447
1448static const struct user_regset s390_compat_regsets[] = {
1449	{
1450		.core_note_type = NT_PRSTATUS,
1451		.n = sizeof(s390_compat_regs) / sizeof(compat_long_t),
1452		.size = sizeof(compat_long_t),
1453		.align = sizeof(compat_long_t),
1454		.regset_get = s390_compat_regs_get,
1455		.set = s390_compat_regs_set,
1456	},
1457	{
1458		.core_note_type = NT_PRFPREG,
1459		.n = sizeof(s390_fp_regs) / sizeof(compat_long_t),
1460		.size = sizeof(compat_long_t),
1461		.align = sizeof(compat_long_t),
1462		.regset_get = s390_fpregs_get,
1463		.set = s390_fpregs_set,
1464	},
1465	{
1466		.core_note_type = NT_S390_SYSTEM_CALL,
1467		.n = 1,
1468		.size = sizeof(compat_uint_t),
1469		.align = sizeof(compat_uint_t),
1470		.regset_get = s390_system_call_get,
1471		.set = s390_system_call_set,
1472	},
1473	{
1474		.core_note_type = NT_S390_LAST_BREAK,
1475		.n = 1,
1476		.size = sizeof(long),
1477		.align = sizeof(long),
1478		.regset_get = s390_compat_last_break_get,
1479		.set = s390_compat_last_break_set,
1480	},
1481	{
1482		.core_note_type = NT_S390_TDB,
1483		.n = 1,
1484		.size = 256,
1485		.align = 1,
1486		.regset_get = s390_tdb_get,
1487		.set = s390_tdb_set,
1488	},
1489	{
1490		.core_note_type = NT_S390_VXRS_LOW,
1491		.n = __NUM_VXRS_LOW,
1492		.size = sizeof(__u64),
1493		.align = sizeof(__u64),
1494		.regset_get = s390_vxrs_low_get,
1495		.set = s390_vxrs_low_set,
1496	},
1497	{
1498		.core_note_type = NT_S390_VXRS_HIGH,
1499		.n = __NUM_VXRS_HIGH,
1500		.size = sizeof(__vector128),
1501		.align = sizeof(__vector128),
1502		.regset_get = s390_vxrs_high_get,
1503		.set = s390_vxrs_high_set,
1504	},
1505	{
1506		.core_note_type = NT_S390_HIGH_GPRS,
1507		.n = sizeof(s390_compat_regs_high) / sizeof(compat_long_t),
1508		.size = sizeof(compat_long_t),
1509		.align = sizeof(compat_long_t),
1510		.regset_get = s390_compat_regs_high_get,
1511		.set = s390_compat_regs_high_set,
1512	},
1513	{
1514		.core_note_type = NT_S390_GS_CB,
1515		.n = sizeof(struct gs_cb) / sizeof(__u64),
1516		.size = sizeof(__u64),
1517		.align = sizeof(__u64),
1518		.regset_get = s390_gs_cb_get,
1519		.set = s390_gs_cb_set,
1520	},
1521	{
1522		.core_note_type = NT_S390_GS_BC,
1523		.n = sizeof(struct gs_cb) / sizeof(__u64),
1524		.size = sizeof(__u64),
1525		.align = sizeof(__u64),
1526		.regset_get = s390_gs_bc_get,
1527		.set = s390_gs_bc_set,
1528	},
1529	{
1530		.core_note_type = NT_S390_RI_CB,
1531		.n = sizeof(struct runtime_instr_cb) / sizeof(__u64),
1532		.size = sizeof(__u64),
1533		.align = sizeof(__u64),
1534		.regset_get = s390_runtime_instr_get,
1535		.set = s390_runtime_instr_set,
1536	},
1537};
1538
1539static const struct user_regset_view user_s390_compat_view = {
1540	.name = "s390",
1541	.e_machine = EM_S390,
1542	.regsets = s390_compat_regsets,
1543	.n = ARRAY_SIZE(s390_compat_regsets)
1544};
1545#endif
1546
1547const struct user_regset_view *task_user_regset_view(struct task_struct *task)
1548{
1549#ifdef CONFIG_COMPAT
1550	if (test_tsk_thread_flag(task, TIF_31BIT))
1551		return &user_s390_compat_view;
1552#endif
1553	return &user_s390_view;
1554}
1555
1556static const char *gpr_names[NUM_GPRS] = {
1557	"r0", "r1",  "r2",  "r3",  "r4",  "r5",  "r6",  "r7",
1558	"r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
1559};
1560
1561unsigned long regs_get_register(struct pt_regs *regs, unsigned int offset)
1562{
1563	if (offset >= NUM_GPRS)
1564		return 0;
1565	return regs->gprs[offset];
1566}
1567
1568int regs_query_register_offset(const char *name)
1569{
1570	unsigned long offset;
1571
1572	if (!name || *name != 'r')
1573		return -EINVAL;
1574	if (kstrtoul(name + 1, 10, &offset))
1575		return -EINVAL;
1576	if (offset >= NUM_GPRS)
1577		return -EINVAL;
1578	return offset;
1579}
1580
1581const char *regs_query_register_name(unsigned int offset)
1582{
1583	if (offset >= NUM_GPRS)
1584		return NULL;
1585	return gpr_names[offset];
1586}
1587
1588static int regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
1589{
1590	unsigned long ksp = kernel_stack_pointer(regs);
1591
1592	return (addr & ~(THREAD_SIZE - 1)) == (ksp & ~(THREAD_SIZE - 1));
1593}
1594
1595/**
1596 * regs_get_kernel_stack_nth() - get Nth entry of the stack
1597 * @regs:pt_regs which contains kernel stack pointer.
1598 * @n:stack entry number.
1599 *
1600 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
1601 * is specifined by @regs. If the @n th entry is NOT in the kernel stack,
1602 * this returns 0.
1603 */
1604unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
1605{
1606	unsigned long addr;
1607
1608	addr = kernel_stack_pointer(regs) + n * sizeof(long);
1609	if (!regs_within_kernel_stack(regs, addr))
1610		return 0;
1611	return *(unsigned long *)addr;
1612}
v6.13.7
   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  Ptrace user space interface.
   4 *
   5 *    Copyright IBM Corp. 1999, 2010
   6 *    Author(s): Denis Joseph Barrow
   7 *               Martin Schwidefsky (schwidefsky@de.ibm.com)
   8 */
   9
  10#include "asm/ptrace.h"
  11#include <linux/kernel.h>
  12#include <linux/sched.h>
  13#include <linux/sched/task_stack.h>
  14#include <linux/mm.h>
  15#include <linux/smp.h>
  16#include <linux/errno.h>
  17#include <linux/ptrace.h>
  18#include <linux/user.h>
  19#include <linux/security.h>
  20#include <linux/audit.h>
  21#include <linux/signal.h>
  22#include <linux/elf.h>
  23#include <linux/regset.h>
  24#include <linux/seccomp.h>
  25#include <linux/compat.h>
  26#include <trace/syscall.h>
  27#include <asm/guarded_storage.h>
  28#include <asm/access-regs.h>
  29#include <asm/page.h>
  30#include <linux/uaccess.h>
  31#include <asm/unistd.h>
 
  32#include <asm/runtime_instr.h>
  33#include <asm/facility.h>
  34#include <asm/fpu.h>
  35
  36#include "entry.h"
  37
  38#ifdef CONFIG_COMPAT
  39#include "compat_ptrace.h"
  40#endif
  41
  42void update_cr_regs(struct task_struct *task)
  43{
  44	struct pt_regs *regs = task_pt_regs(task);
  45	struct thread_struct *thread = &task->thread;
  46	union ctlreg0 cr0_old, cr0_new;
  47	union ctlreg2 cr2_old, cr2_new;
  48	int cr0_changed, cr2_changed;
  49	union {
  50		struct ctlreg regs[3];
  51		struct {
  52			struct ctlreg control;
  53			struct ctlreg start;
  54			struct ctlreg end;
  55		};
  56	} old, new;
  57
  58	local_ctl_store(0, &cr0_old.reg);
  59	local_ctl_store(2, &cr2_old.reg);
  60	cr0_new = cr0_old;
  61	cr2_new = cr2_old;
  62	/* Take care of the enable/disable of transactional execution. */
  63	if (MACHINE_HAS_TE) {
  64		/* Set or clear transaction execution TXC bit 8. */
  65		cr0_new.tcx = 1;
  66		if (task->thread.per_flags & PER_FLAG_NO_TE)
  67			cr0_new.tcx = 0;
  68		/* Set or clear transaction execution TDC bits 62 and 63. */
  69		cr2_new.tdc = 0;
  70		if (task->thread.per_flags & PER_FLAG_TE_ABORT_RAND) {
  71			if (task->thread.per_flags & PER_FLAG_TE_ABORT_RAND_TEND)
  72				cr2_new.tdc = 1;
  73			else
  74				cr2_new.tdc = 2;
  75		}
  76	}
  77	/* Take care of enable/disable of guarded storage. */
  78	if (MACHINE_HAS_GS) {
  79		cr2_new.gse = 0;
  80		if (task->thread.gs_cb)
  81			cr2_new.gse = 1;
  82	}
  83	/* Load control register 0/2 iff changed */
  84	cr0_changed = cr0_new.val != cr0_old.val;
  85	cr2_changed = cr2_new.val != cr2_old.val;
  86	if (cr0_changed)
  87		local_ctl_load(0, &cr0_new.reg);
  88	if (cr2_changed)
  89		local_ctl_load(2, &cr2_new.reg);
  90	/* Copy user specified PER registers */
  91	new.control.val = thread->per_user.control;
  92	new.start.val = thread->per_user.start;
  93	new.end.val = thread->per_user.end;
  94
  95	/* merge TIF_SINGLE_STEP into user specified PER registers. */
  96	if (test_tsk_thread_flag(task, TIF_SINGLE_STEP) ||
  97	    test_tsk_thread_flag(task, TIF_UPROBE_SINGLESTEP)) {
  98		if (test_tsk_thread_flag(task, TIF_BLOCK_STEP))
  99			new.control.val |= PER_EVENT_BRANCH;
 100		else
 101			new.control.val |= PER_EVENT_IFETCH;
 102		new.control.val |= PER_CONTROL_SUSPENSION;
 103		new.control.val |= PER_EVENT_TRANSACTION_END;
 104		if (test_tsk_thread_flag(task, TIF_UPROBE_SINGLESTEP))
 105			new.control.val |= PER_EVENT_IFETCH;
 106		new.start.val = 0;
 107		new.end.val = -1UL;
 108	}
 109
 110	/* Take care of the PER enablement bit in the PSW. */
 111	if (!(new.control.val & PER_EVENT_MASK)) {
 112		regs->psw.mask &= ~PSW_MASK_PER;
 113		return;
 114	}
 115	regs->psw.mask |= PSW_MASK_PER;
 116	__local_ctl_store(9, 11, old.regs);
 117	if (memcmp(&new, &old, sizeof(struct per_regs)) != 0)
 118		__local_ctl_load(9, 11, new.regs);
 119}
 120
 121void user_enable_single_step(struct task_struct *task)
 122{
 123	clear_tsk_thread_flag(task, TIF_BLOCK_STEP);
 124	set_tsk_thread_flag(task, TIF_SINGLE_STEP);
 125}
 126
 127void user_disable_single_step(struct task_struct *task)
 128{
 129	clear_tsk_thread_flag(task, TIF_BLOCK_STEP);
 130	clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
 131}
 132
 133void user_enable_block_step(struct task_struct *task)
 134{
 135	set_tsk_thread_flag(task, TIF_SINGLE_STEP);
 136	set_tsk_thread_flag(task, TIF_BLOCK_STEP);
 137}
 138
 139/*
 140 * Called by kernel/ptrace.c when detaching..
 141 *
 142 * Clear all debugging related fields.
 143 */
 144void ptrace_disable(struct task_struct *task)
 145{
 146	memset(&task->thread.per_user, 0, sizeof(task->thread.per_user));
 147	memset(&task->thread.per_event, 0, sizeof(task->thread.per_event));
 148	clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
 149	clear_tsk_thread_flag(task, TIF_PER_TRAP);
 150	task->thread.per_flags = 0;
 151}
 152
 153#define __ADDR_MASK 7
 154
 155static inline unsigned long __peek_user_per(struct task_struct *child,
 156					    addr_t addr)
 157{
 158	if (addr == offsetof(struct per_struct_kernel, cr9))
 159		/* Control bits of the active per set. */
 160		return test_thread_flag(TIF_SINGLE_STEP) ?
 161			PER_EVENT_IFETCH : child->thread.per_user.control;
 162	else if (addr == offsetof(struct per_struct_kernel, cr10))
 163		/* Start address of the active per set. */
 164		return test_thread_flag(TIF_SINGLE_STEP) ?
 165			0 : child->thread.per_user.start;
 166	else if (addr == offsetof(struct per_struct_kernel, cr11))
 167		/* End address of the active per set. */
 168		return test_thread_flag(TIF_SINGLE_STEP) ?
 169			-1UL : child->thread.per_user.end;
 170	else if (addr == offsetof(struct per_struct_kernel, bits))
 171		/* Single-step bit. */
 172		return test_thread_flag(TIF_SINGLE_STEP) ?
 173			(1UL << (BITS_PER_LONG - 1)) : 0;
 174	else if (addr == offsetof(struct per_struct_kernel, starting_addr))
 175		/* Start address of the user specified per set. */
 176		return child->thread.per_user.start;
 177	else if (addr == offsetof(struct per_struct_kernel, ending_addr))
 178		/* End address of the user specified per set. */
 179		return child->thread.per_user.end;
 180	else if (addr == offsetof(struct per_struct_kernel, perc_atmid))
 181		/* PER code, ATMID and AI of the last PER trap */
 182		return (unsigned long)
 183			child->thread.per_event.cause << (BITS_PER_LONG - 16);
 184	else if (addr == offsetof(struct per_struct_kernel, address))
 185		/* Address of the last PER trap */
 186		return child->thread.per_event.address;
 187	else if (addr == offsetof(struct per_struct_kernel, access_id))
 188		/* Access id of the last PER trap */
 189		return (unsigned long)
 190			child->thread.per_event.paid << (BITS_PER_LONG - 8);
 191	return 0;
 192}
 193
 194/*
 195 * Read the word at offset addr from the user area of a process. The
 196 * trouble here is that the information is littered over different
 197 * locations. The process registers are found on the kernel stack,
 198 * the floating point stuff and the trace settings are stored in
 199 * the task structure. In addition the different structures in
 200 * struct user contain pad bytes that should be read as zeroes.
 201 * Lovely...
 202 */
 203static unsigned long __peek_user(struct task_struct *child, addr_t addr)
 204{
 205	addr_t offset, tmp;
 206
 207	if (addr < offsetof(struct user, regs.acrs)) {
 208		/*
 209		 * psw and gprs are stored on the stack
 210		 */
 211		tmp = *(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr);
 212		if (addr == offsetof(struct user, regs.psw.mask)) {
 213			/* Return a clean psw mask. */
 214			tmp &= PSW_MASK_USER | PSW_MASK_RI;
 215			tmp |= PSW_USER_BITS;
 216		}
 217
 218	} else if (addr < offsetof(struct user, regs.orig_gpr2)) {
 219		/*
 220		 * access registers are stored in the thread structure
 221		 */
 222		offset = addr - offsetof(struct user, regs.acrs);
 223		/*
 224		 * Very special case: old & broken 64 bit gdb reading
 225		 * from acrs[15]. Result is a 64 bit value. Read the
 226		 * 32 bit acrs[15] value and shift it by 32. Sick...
 227		 */
 228		if (addr == offsetof(struct user, regs.acrs[15]))
 229			tmp = ((unsigned long) child->thread.acrs[15]) << 32;
 230		else
 231			tmp = *(addr_t *)((addr_t) &child->thread.acrs + offset);
 232
 233	} else if (addr == offsetof(struct user, regs.orig_gpr2)) {
 234		/*
 235		 * orig_gpr2 is stored on the kernel stack
 236		 */
 237		tmp = (addr_t) task_pt_regs(child)->orig_gpr2;
 238
 239	} else if (addr < offsetof(struct user, regs.fp_regs)) {
 240		/*
 241		 * prevent reads of padding hole between
 242		 * orig_gpr2 and fp_regs on s390.
 243		 */
 244		tmp = 0;
 245
 246	} else if (addr == offsetof(struct user, regs.fp_regs.fpc)) {
 247		/*
 248		 * floating point control reg. is in the thread structure
 249		 */
 250		tmp = child->thread.ufpu.fpc;
 251		tmp <<= BITS_PER_LONG - 32;
 252
 253	} else if (addr < offsetof(struct user, regs.fp_regs) + sizeof(s390_fp_regs)) {
 254		/*
 255		 * floating point regs. are in the child->thread.ufpu.vxrs array
 
 256		 */
 257		offset = addr - offsetof(struct user, regs.fp_regs.fprs);
 258		tmp = *(addr_t *)((addr_t)child->thread.ufpu.vxrs + 2 * offset);
 
 
 
 
 
 
 259	} else if (addr < offsetof(struct user, regs.per_info) + sizeof(per_struct)) {
 260		/*
 261		 * Handle access to the per_info structure.
 262		 */
 263		addr -= offsetof(struct user, regs.per_info);
 264		tmp = __peek_user_per(child, addr);
 265
 266	} else
 267		tmp = 0;
 268
 269	return tmp;
 270}
 271
 272static int
 273peek_user(struct task_struct *child, addr_t addr, addr_t data)
 274{
 275	addr_t tmp, mask;
 276
 277	/*
 278	 * Stupid gdb peeks/pokes the access registers in 64 bit with
 279	 * an alignment of 4. Programmers from hell...
 280	 */
 281	mask = __ADDR_MASK;
 282	if (addr >= offsetof(struct user, regs.acrs) &&
 283	    addr < offsetof(struct user, regs.orig_gpr2))
 284		mask = 3;
 285	if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
 286		return -EIO;
 287
 288	tmp = __peek_user(child, addr);
 289	return put_user(tmp, (addr_t __user *) data);
 290}
 291
 292static inline void __poke_user_per(struct task_struct *child,
 293				   addr_t addr, addr_t data)
 294{
 295	/*
 296	 * There are only three fields in the per_info struct that the
 297	 * debugger user can write to.
 298	 * 1) cr9: the debugger wants to set a new PER event mask
 299	 * 2) starting_addr: the debugger wants to set a new starting
 300	 *    address to use with the PER event mask.
 301	 * 3) ending_addr: the debugger wants to set a new ending
 302	 *    address to use with the PER event mask.
 303	 * The user specified PER event mask and the start and end
 304	 * addresses are used only if single stepping is not in effect.
 305	 * Writes to any other field in per_info are ignored.
 306	 */
 307	if (addr == offsetof(struct per_struct_kernel, cr9))
 308		/* PER event mask of the user specified per set. */
 309		child->thread.per_user.control =
 310			data & (PER_EVENT_MASK | PER_CONTROL_MASK);
 311	else if (addr == offsetof(struct per_struct_kernel, starting_addr))
 312		/* Starting address of the user specified per set. */
 313		child->thread.per_user.start = data;
 314	else if (addr == offsetof(struct per_struct_kernel, ending_addr))
 315		/* Ending address of the user specified per set. */
 316		child->thread.per_user.end = data;
 317}
 318
 319/*
 320 * Write a word to the user area of a process at location addr. This
 321 * operation does have an additional problem compared to peek_user.
 322 * Stores to the program status word and on the floating point
 323 * control register needs to get checked for validity.
 324 */
 325static int __poke_user(struct task_struct *child, addr_t addr, addr_t data)
 326{
 327	addr_t offset;
 328
 329
 330	if (addr < offsetof(struct user, regs.acrs)) {
 331		struct pt_regs *regs = task_pt_regs(child);
 332		/*
 333		 * psw and gprs are stored on the stack
 334		 */
 335		if (addr == offsetof(struct user, regs.psw.mask)) {
 336			unsigned long mask = PSW_MASK_USER;
 337
 338			mask |= is_ri_task(child) ? PSW_MASK_RI : 0;
 339			if ((data ^ PSW_USER_BITS) & ~mask)
 340				/* Invalid psw mask. */
 341				return -EINVAL;
 342			if ((data & PSW_MASK_ASC) == PSW_ASC_HOME)
 343				/* Invalid address-space-control bits */
 344				return -EINVAL;
 345			if ((data & PSW_MASK_EA) && !(data & PSW_MASK_BA))
 346				/* Invalid addressing mode bits */
 347				return -EINVAL;
 348		}
 349
 350		if (test_pt_regs_flag(regs, PIF_SYSCALL) &&
 351			addr == offsetof(struct user, regs.gprs[2])) {
 352			struct pt_regs *regs = task_pt_regs(child);
 353
 354			regs->int_code = 0x20000 | (data & 0xffff);
 355		}
 356		*(addr_t *)((addr_t) &regs->psw + addr) = data;
 357	} else if (addr < offsetof(struct user, regs.orig_gpr2)) {
 358		/*
 359		 * access registers are stored in the thread structure
 360		 */
 361		offset = addr - offsetof(struct user, regs.acrs);
 362		/*
 363		 * Very special case: old & broken 64 bit gdb writing
 364		 * to acrs[15] with a 64 bit value. Ignore the lower
 365		 * half of the value and write the upper 32 bit to
 366		 * acrs[15]. Sick...
 367		 */
 368		if (addr == offsetof(struct user, regs.acrs[15]))
 369			child->thread.acrs[15] = (unsigned int) (data >> 32);
 370		else
 371			*(addr_t *)((addr_t) &child->thread.acrs + offset) = data;
 372
 373	} else if (addr == offsetof(struct user, regs.orig_gpr2)) {
 374		/*
 375		 * orig_gpr2 is stored on the kernel stack
 376		 */
 377		task_pt_regs(child)->orig_gpr2 = data;
 378
 379	} else if (addr < offsetof(struct user, regs.fp_regs)) {
 380		/*
 381		 * prevent writes of padding hole between
 382		 * orig_gpr2 and fp_regs on s390.
 383		 */
 384		return 0;
 385
 386	} else if (addr == offsetof(struct user, regs.fp_regs.fpc)) {
 387		/*
 388		 * floating point control reg. is in the thread structure
 389		 */
 390		if ((unsigned int)data != 0)
 391			return -EINVAL;
 392		child->thread.ufpu.fpc = data >> (BITS_PER_LONG - 32);
 393
 394	} else if (addr < offsetof(struct user, regs.fp_regs) + sizeof(s390_fp_regs)) {
 395		/*
 396		 * floating point regs. are in the child->thread.ufpu.vxrs array
 
 397		 */
 398		offset = addr - offsetof(struct user, regs.fp_regs.fprs);
 399		*(addr_t *)((addr_t)child->thread.ufpu.vxrs + 2 * offset) = data;
 
 
 
 
 
 
 400	} else if (addr < offsetof(struct user, regs.per_info) + sizeof(per_struct)) {
 401		/*
 402		 * Handle access to the per_info structure.
 403		 */
 404		addr -= offsetof(struct user, regs.per_info);
 405		__poke_user_per(child, addr, data);
 406
 407	}
 408
 409	return 0;
 410}
 411
 412static int poke_user(struct task_struct *child, addr_t addr, addr_t data)
 413{
 414	addr_t mask;
 415
 416	/*
 417	 * Stupid gdb peeks/pokes the access registers in 64 bit with
 418	 * an alignment of 4. Programmers from hell indeed...
 419	 */
 420	mask = __ADDR_MASK;
 421	if (addr >= offsetof(struct user, regs.acrs) &&
 422	    addr < offsetof(struct user, regs.orig_gpr2))
 423		mask = 3;
 424	if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
 425		return -EIO;
 426
 427	return __poke_user(child, addr, data);
 428}
 429
 430long arch_ptrace(struct task_struct *child, long request,
 431		 unsigned long addr, unsigned long data)
 432{
 433	ptrace_area parea; 
 434	int copied, ret;
 435
 436	switch (request) {
 437	case PTRACE_PEEKUSR:
 438		/* read the word at location addr in the USER area. */
 439		return peek_user(child, addr, data);
 440
 441	case PTRACE_POKEUSR:
 442		/* write the word at location addr in the USER area */
 443		return poke_user(child, addr, data);
 444
 445	case PTRACE_PEEKUSR_AREA:
 446	case PTRACE_POKEUSR_AREA:
 447		if (copy_from_user(&parea, (void __force __user *) addr,
 448							sizeof(parea)))
 449			return -EFAULT;
 450		addr = parea.kernel_addr;
 451		data = parea.process_addr;
 452		copied = 0;
 453		while (copied < parea.len) {
 454			if (request == PTRACE_PEEKUSR_AREA)
 455				ret = peek_user(child, addr, data);
 456			else {
 457				addr_t utmp;
 458				if (get_user(utmp,
 459					     (addr_t __force __user *) data))
 460					return -EFAULT;
 461				ret = poke_user(child, addr, utmp);
 462			}
 463			if (ret)
 464				return ret;
 465			addr += sizeof(unsigned long);
 466			data += sizeof(unsigned long);
 467			copied += sizeof(unsigned long);
 468		}
 469		return 0;
 470	case PTRACE_GET_LAST_BREAK:
 471		return put_user(child->thread.last_break, (unsigned long __user *)data);
 472	case PTRACE_ENABLE_TE:
 473		if (!MACHINE_HAS_TE)
 474			return -EIO;
 475		child->thread.per_flags &= ~PER_FLAG_NO_TE;
 476		return 0;
 477	case PTRACE_DISABLE_TE:
 478		if (!MACHINE_HAS_TE)
 479			return -EIO;
 480		child->thread.per_flags |= PER_FLAG_NO_TE;
 481		child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND;
 482		return 0;
 483	case PTRACE_TE_ABORT_RAND:
 484		if (!MACHINE_HAS_TE || (child->thread.per_flags & PER_FLAG_NO_TE))
 485			return -EIO;
 486		switch (data) {
 487		case 0UL:
 488			child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND;
 489			break;
 490		case 1UL:
 491			child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND;
 492			child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND_TEND;
 493			break;
 494		case 2UL:
 495			child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND;
 496			child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND_TEND;
 497			break;
 498		default:
 499			return -EINVAL;
 500		}
 501		return 0;
 502	default:
 503		return ptrace_request(child, request, addr, data);
 504	}
 505}
 506
 507#ifdef CONFIG_COMPAT
 508/*
 509 * Now the fun part starts... a 31 bit program running in the
 510 * 31 bit emulation tracing another program. PTRACE_PEEKTEXT,
 511 * PTRACE_PEEKDATA, PTRACE_POKETEXT and PTRACE_POKEDATA are easy
 512 * to handle, the difference to the 64 bit versions of the requests
 513 * is that the access is done in multiples of 4 byte instead of
 514 * 8 bytes (sizeof(unsigned long) on 31/64 bit).
 515 * The ugly part are PTRACE_PEEKUSR, PTRACE_PEEKUSR_AREA,
 516 * PTRACE_POKEUSR and PTRACE_POKEUSR_AREA. If the traced program
 517 * is a 31 bit program too, the content of struct user can be
 518 * emulated. A 31 bit program peeking into the struct user of
 519 * a 64 bit program is a no-no.
 520 */
 521
 522/*
 523 * Same as peek_user_per but for a 31 bit program.
 524 */
 525static inline __u32 __peek_user_per_compat(struct task_struct *child,
 526					   addr_t addr)
 527{
 528	if (addr == offsetof(struct compat_per_struct_kernel, cr9))
 529		/* Control bits of the active per set. */
 530		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
 531			PER_EVENT_IFETCH : child->thread.per_user.control;
 532	else if (addr == offsetof(struct compat_per_struct_kernel, cr10))
 533		/* Start address of the active per set. */
 534		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
 535			0 : child->thread.per_user.start;
 536	else if (addr == offsetof(struct compat_per_struct_kernel, cr11))
 537		/* End address of the active per set. */
 538		return test_thread_flag(TIF_SINGLE_STEP) ?
 539			PSW32_ADDR_INSN : child->thread.per_user.end;
 540	else if (addr == offsetof(struct compat_per_struct_kernel, bits))
 541		/* Single-step bit. */
 542		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
 543			0x80000000 : 0;
 544	else if (addr == offsetof(struct compat_per_struct_kernel, starting_addr))
 545		/* Start address of the user specified per set. */
 546		return (__u32) child->thread.per_user.start;
 547	else if (addr == offsetof(struct compat_per_struct_kernel, ending_addr))
 548		/* End address of the user specified per set. */
 549		return (__u32) child->thread.per_user.end;
 550	else if (addr == offsetof(struct compat_per_struct_kernel, perc_atmid))
 551		/* PER code, ATMID and AI of the last PER trap */
 552		return (__u32) child->thread.per_event.cause << 16;
 553	else if (addr == offsetof(struct compat_per_struct_kernel, address))
 554		/* Address of the last PER trap */
 555		return (__u32) child->thread.per_event.address;
 556	else if (addr == offsetof(struct compat_per_struct_kernel, access_id))
 557		/* Access id of the last PER trap */
 558		return (__u32) child->thread.per_event.paid << 24;
 559	return 0;
 560}
 561
 562/*
 563 * Same as peek_user but for a 31 bit program.
 564 */
 565static u32 __peek_user_compat(struct task_struct *child, addr_t addr)
 566{
 567	addr_t offset;
 568	__u32 tmp;
 569
 570	if (addr < offsetof(struct compat_user, regs.acrs)) {
 571		struct pt_regs *regs = task_pt_regs(child);
 572		/*
 573		 * psw and gprs are stored on the stack
 574		 */
 575		if (addr == offsetof(struct compat_user, regs.psw.mask)) {
 576			/* Fake a 31 bit psw mask. */
 577			tmp = (__u32)(regs->psw.mask >> 32);
 578			tmp &= PSW32_MASK_USER | PSW32_MASK_RI;
 579			tmp |= PSW32_USER_BITS;
 580		} else if (addr == offsetof(struct compat_user, regs.psw.addr)) {
 581			/* Fake a 31 bit psw address. */
 582			tmp = (__u32) regs->psw.addr |
 583				(__u32)(regs->psw.mask & PSW_MASK_BA);
 584		} else {
 585			/* gpr 0-15 */
 586			tmp = *(__u32 *)((addr_t) &regs->psw + addr*2 + 4);
 587		}
 588	} else if (addr < offsetof(struct compat_user, regs.orig_gpr2)) {
 589		/*
 590		 * access registers are stored in the thread structure
 591		 */
 592		offset = addr - offsetof(struct compat_user, regs.acrs);
 593		tmp = *(__u32*)((addr_t) &child->thread.acrs + offset);
 594
 595	} else if (addr == offsetof(struct compat_user, regs.orig_gpr2)) {
 596		/*
 597		 * orig_gpr2 is stored on the kernel stack
 598		 */
 599		tmp = *(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4);
 600
 601	} else if (addr < offsetof(struct compat_user, regs.fp_regs)) {
 602		/*
 603		 * prevent reads of padding hole between
 604		 * orig_gpr2 and fp_regs on s390.
 605		 */
 606		tmp = 0;
 607
 608	} else if (addr == offsetof(struct compat_user, regs.fp_regs.fpc)) {
 609		/*
 610		 * floating point control reg. is in the thread structure
 611		 */
 612		tmp = child->thread.ufpu.fpc;
 613
 614	} else if (addr < offsetof(struct compat_user, regs.fp_regs) + sizeof(s390_fp_regs)) {
 615		/*
 616		 * floating point regs. are in the child->thread.ufpu.vxrs array
 
 617		 */
 618		offset = addr - offsetof(struct compat_user, regs.fp_regs.fprs);
 619		tmp = *(__u32 *)((addr_t)child->thread.ufpu.vxrs + 2 * offset);
 
 
 
 
 
 
 620	} else if (addr < offsetof(struct compat_user, regs.per_info) + sizeof(struct compat_per_struct_kernel)) {
 621		/*
 622		 * Handle access to the per_info structure.
 623		 */
 624		addr -= offsetof(struct compat_user, regs.per_info);
 625		tmp = __peek_user_per_compat(child, addr);
 626
 627	} else
 628		tmp = 0;
 629
 630	return tmp;
 631}
 632
 633static int peek_user_compat(struct task_struct *child,
 634			    addr_t addr, addr_t data)
 635{
 636	__u32 tmp;
 637
 638	if (!is_compat_task() || (addr & 3) || addr > sizeof(struct user) - 3)
 639		return -EIO;
 640
 641	tmp = __peek_user_compat(child, addr);
 642	return put_user(tmp, (__u32 __user *) data);
 643}
 644
 645/*
 646 * Same as poke_user_per but for a 31 bit program.
 647 */
 648static inline void __poke_user_per_compat(struct task_struct *child,
 649					  addr_t addr, __u32 data)
 650{
 651	if (addr == offsetof(struct compat_per_struct_kernel, cr9))
 652		/* PER event mask of the user specified per set. */
 653		child->thread.per_user.control =
 654			data & (PER_EVENT_MASK | PER_CONTROL_MASK);
 655	else if (addr == offsetof(struct compat_per_struct_kernel, starting_addr))
 656		/* Starting address of the user specified per set. */
 657		child->thread.per_user.start = data;
 658	else if (addr == offsetof(struct compat_per_struct_kernel, ending_addr))
 659		/* Ending address of the user specified per set. */
 660		child->thread.per_user.end = data;
 661}
 662
 663/*
 664 * Same as poke_user but for a 31 bit program.
 665 */
 666static int __poke_user_compat(struct task_struct *child,
 667			      addr_t addr, addr_t data)
 668{
 669	__u32 tmp = (__u32) data;
 670	addr_t offset;
 671
 672	if (addr < offsetof(struct compat_user, regs.acrs)) {
 673		struct pt_regs *regs = task_pt_regs(child);
 674		/*
 675		 * psw, gprs, acrs and orig_gpr2 are stored on the stack
 676		 */
 677		if (addr == offsetof(struct compat_user, regs.psw.mask)) {
 678			__u32 mask = PSW32_MASK_USER;
 679
 680			mask |= is_ri_task(child) ? PSW32_MASK_RI : 0;
 681			/* Build a 64 bit psw mask from 31 bit mask. */
 682			if ((tmp ^ PSW32_USER_BITS) & ~mask)
 683				/* Invalid psw mask. */
 684				return -EINVAL;
 685			if ((data & PSW32_MASK_ASC) == PSW32_ASC_HOME)
 686				/* Invalid address-space-control bits */
 687				return -EINVAL;
 688			regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
 689				(regs->psw.mask & PSW_MASK_BA) |
 690				(__u64)(tmp & mask) << 32;
 691		} else if (addr == offsetof(struct compat_user, regs.psw.addr)) {
 692			/* Build a 64 bit psw address from 31 bit address. */
 693			regs->psw.addr = (__u64) tmp & PSW32_ADDR_INSN;
 694			/* Transfer 31 bit amode bit to psw mask. */
 695			regs->psw.mask = (regs->psw.mask & ~PSW_MASK_BA) |
 696				(__u64)(tmp & PSW32_ADDR_AMODE);
 697		} else {
 698			if (test_pt_regs_flag(regs, PIF_SYSCALL) &&
 699				addr == offsetof(struct compat_user, regs.gprs[2])) {
 700				struct pt_regs *regs = task_pt_regs(child);
 701
 702				regs->int_code = 0x20000 | (data & 0xffff);
 703			}
 704			/* gpr 0-15 */
 705			*(__u32*)((addr_t) &regs->psw + addr*2 + 4) = tmp;
 706		}
 707	} else if (addr < offsetof(struct compat_user, regs.orig_gpr2)) {
 708		/*
 709		 * access registers are stored in the thread structure
 710		 */
 711		offset = addr - offsetof(struct compat_user, regs.acrs);
 712		*(__u32*)((addr_t) &child->thread.acrs + offset) = tmp;
 713
 714	} else if (addr == offsetof(struct compat_user, regs.orig_gpr2)) {
 715		/*
 716		 * orig_gpr2 is stored on the kernel stack
 717		 */
 718		*(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4) = tmp;
 719
 720	} else if (addr < offsetof(struct compat_user, regs.fp_regs)) {
 721		/*
 722		 * prevent writess of padding hole between
 723		 * orig_gpr2 and fp_regs on s390.
 724		 */
 725		return 0;
 726
 727	} else if (addr == offsetof(struct compat_user, regs.fp_regs.fpc)) {
 728		/*
 729		 * floating point control reg. is in the thread structure
 730		 */
 731		child->thread.ufpu.fpc = data;
 732
 733	} else if (addr < offsetof(struct compat_user, regs.fp_regs) + sizeof(s390_fp_regs)) {
 734		/*
 735		 * floating point regs. are in the child->thread.ufpu.vxrs array
 
 736		 */
 737		offset = addr - offsetof(struct compat_user, regs.fp_regs.fprs);
 738		*(__u32 *)((addr_t)child->thread.ufpu.vxrs + 2 * offset) = tmp;
 
 
 
 
 
 
 739	} else if (addr < offsetof(struct compat_user, regs.per_info) + sizeof(struct compat_per_struct_kernel)) {
 740		/*
 741		 * Handle access to the per_info structure.
 742		 */
 743		addr -= offsetof(struct compat_user, regs.per_info);
 744		__poke_user_per_compat(child, addr, data);
 745	}
 746
 747	return 0;
 748}
 749
 750static int poke_user_compat(struct task_struct *child,
 751			    addr_t addr, addr_t data)
 752{
 753	if (!is_compat_task() || (addr & 3) ||
 754	    addr > sizeof(struct compat_user) - 3)
 755		return -EIO;
 756
 757	return __poke_user_compat(child, addr, data);
 758}
 759
 760long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 761			compat_ulong_t caddr, compat_ulong_t cdata)
 762{
 763	unsigned long addr = caddr;
 764	unsigned long data = cdata;
 765	compat_ptrace_area parea;
 766	int copied, ret;
 767
 768	switch (request) {
 769	case PTRACE_PEEKUSR:
 770		/* read the word at location addr in the USER area. */
 771		return peek_user_compat(child, addr, data);
 772
 773	case PTRACE_POKEUSR:
 774		/* write the word at location addr in the USER area */
 775		return poke_user_compat(child, addr, data);
 776
 777	case PTRACE_PEEKUSR_AREA:
 778	case PTRACE_POKEUSR_AREA:
 779		if (copy_from_user(&parea, (void __force __user *) addr,
 780							sizeof(parea)))
 781			return -EFAULT;
 782		addr = parea.kernel_addr;
 783		data = parea.process_addr;
 784		copied = 0;
 785		while (copied < parea.len) {
 786			if (request == PTRACE_PEEKUSR_AREA)
 787				ret = peek_user_compat(child, addr, data);
 788			else {
 789				__u32 utmp;
 790				if (get_user(utmp,
 791					     (__u32 __force __user *) data))
 792					return -EFAULT;
 793				ret = poke_user_compat(child, addr, utmp);
 794			}
 795			if (ret)
 796				return ret;
 797			addr += sizeof(unsigned int);
 798			data += sizeof(unsigned int);
 799			copied += sizeof(unsigned int);
 800		}
 801		return 0;
 802	case PTRACE_GET_LAST_BREAK:
 803		return put_user(child->thread.last_break, (unsigned int __user *)data);
 804	}
 805	return compat_ptrace_request(child, request, addr, data);
 806}
 807#endif
 808
 809/*
 810 * user_regset definitions.
 811 */
 812
 813static int s390_regs_get(struct task_struct *target,
 814			 const struct user_regset *regset,
 815			 struct membuf to)
 816{
 817	unsigned pos;
 818	if (target == current)
 819		save_access_regs(target->thread.acrs);
 820
 821	for (pos = 0; pos < sizeof(s390_regs); pos += sizeof(long))
 822		membuf_store(&to, __peek_user(target, pos));
 823	return 0;
 824}
 825
 826static int s390_regs_set(struct task_struct *target,
 827			 const struct user_regset *regset,
 828			 unsigned int pos, unsigned int count,
 829			 const void *kbuf, const void __user *ubuf)
 830{
 831	int rc = 0;
 832
 833	if (target == current)
 834		save_access_regs(target->thread.acrs);
 835
 836	if (kbuf) {
 837		const unsigned long *k = kbuf;
 838		while (count > 0 && !rc) {
 839			rc = __poke_user(target, pos, *k++);
 840			count -= sizeof(*k);
 841			pos += sizeof(*k);
 842		}
 843	} else {
 844		const unsigned long  __user *u = ubuf;
 845		while (count > 0 && !rc) {
 846			unsigned long word;
 847			rc = __get_user(word, u++);
 848			if (rc)
 849				break;
 850			rc = __poke_user(target, pos, word);
 851			count -= sizeof(*u);
 852			pos += sizeof(*u);
 853		}
 854	}
 855
 856	if (rc == 0 && target == current)
 857		restore_access_regs(target->thread.acrs);
 858
 859	return rc;
 860}
 861
 862static int s390_fpregs_get(struct task_struct *target,
 863			   const struct user_regset *regset,
 864			   struct membuf to)
 865{
 866	_s390_fp_regs fp_regs;
 867
 868	if (target == current)
 869		save_user_fpu_regs();
 870
 871	fp_regs.fpc = target->thread.ufpu.fpc;
 872	fpregs_store(&fp_regs, &target->thread.ufpu);
 873
 874	return membuf_write(&to, &fp_regs, sizeof(fp_regs));
 875}
 876
 877static int s390_fpregs_set(struct task_struct *target,
 878			   const struct user_regset *regset, unsigned int pos,
 879			   unsigned int count, const void *kbuf,
 880			   const void __user *ubuf)
 881{
 882	int rc = 0;
 883	freg_t fprs[__NUM_FPRS];
 884
 885	if (target == current)
 886		save_user_fpu_regs();
 887	convert_vx_to_fp(fprs, target->thread.ufpu.vxrs);
 
 
 
 
 
 888	if (count > 0 && pos < offsetof(s390_fp_regs, fprs)) {
 889		u32 ufpc[2] = { target->thread.ufpu.fpc, 0 };
 890		rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ufpc,
 891					0, offsetof(s390_fp_regs, fprs));
 892		if (rc)
 893			return rc;
 894		if (ufpc[1] != 0)
 895			return -EINVAL;
 896		target->thread.ufpu.fpc = ufpc[0];
 897	}
 898
 899	if (rc == 0 && count > 0)
 900		rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 901					fprs, offsetof(s390_fp_regs, fprs), -1);
 902	if (rc)
 903		return rc;
 904	convert_fp_to_vx(target->thread.ufpu.vxrs, fprs);
 
 
 
 
 
 905	return rc;
 906}
 907
 908static int s390_last_break_get(struct task_struct *target,
 909			       const struct user_regset *regset,
 910			       struct membuf to)
 911{
 912	return membuf_store(&to, target->thread.last_break);
 913}
 914
 915static int s390_last_break_set(struct task_struct *target,
 916			       const struct user_regset *regset,
 917			       unsigned int pos, unsigned int count,
 918			       const void *kbuf, const void __user *ubuf)
 919{
 920	return 0;
 921}
 922
 923static int s390_tdb_get(struct task_struct *target,
 924			const struct user_regset *regset,
 925			struct membuf to)
 926{
 927	struct pt_regs *regs = task_pt_regs(target);
 928	size_t size;
 929
 930	if (!(regs->int_code & 0x200))
 931		return -ENODATA;
 932	size = sizeof(target->thread.trap_tdb.data);
 933	return membuf_write(&to, target->thread.trap_tdb.data, size);
 934}
 935
 936static int s390_tdb_set(struct task_struct *target,
 937			const struct user_regset *regset,
 938			unsigned int pos, unsigned int count,
 939			const void *kbuf, const void __user *ubuf)
 940{
 941	return 0;
 942}
 943
 944static int s390_vxrs_low_get(struct task_struct *target,
 945			     const struct user_regset *regset,
 946			     struct membuf to)
 947{
 948	__u64 vxrs[__NUM_VXRS_LOW];
 949	int i;
 950
 951	if (!cpu_has_vx())
 952		return -ENODEV;
 953	if (target == current)
 954		save_user_fpu_regs();
 955	for (i = 0; i < __NUM_VXRS_LOW; i++)
 956		vxrs[i] = target->thread.ufpu.vxrs[i].low;
 957	return membuf_write(&to, vxrs, sizeof(vxrs));
 958}
 959
 960static int s390_vxrs_low_set(struct task_struct *target,
 961			     const struct user_regset *regset,
 962			     unsigned int pos, unsigned int count,
 963			     const void *kbuf, const void __user *ubuf)
 964{
 965	__u64 vxrs[__NUM_VXRS_LOW];
 966	int i, rc;
 967
 968	if (!cpu_has_vx())
 969		return -ENODEV;
 970	if (target == current)
 971		save_user_fpu_regs();
 972
 973	for (i = 0; i < __NUM_VXRS_LOW; i++)
 974		vxrs[i] = target->thread.ufpu.vxrs[i].low;
 975
 976	rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, vxrs, 0, -1);
 977	if (rc == 0)
 978		for (i = 0; i < __NUM_VXRS_LOW; i++)
 979			target->thread.ufpu.vxrs[i].low = vxrs[i];
 980
 981	return rc;
 982}
 983
 984static int s390_vxrs_high_get(struct task_struct *target,
 985			      const struct user_regset *regset,
 986			      struct membuf to)
 987{
 988	if (!cpu_has_vx())
 989		return -ENODEV;
 990	if (target == current)
 991		save_user_fpu_regs();
 992	return membuf_write(&to, target->thread.ufpu.vxrs + __NUM_VXRS_LOW,
 993			    __NUM_VXRS_HIGH * sizeof(__vector128));
 994}
 995
 996static int s390_vxrs_high_set(struct task_struct *target,
 997			      const struct user_regset *regset,
 998			      unsigned int pos, unsigned int count,
 999			      const void *kbuf, const void __user *ubuf)
1000{
1001	int rc;
1002
1003	if (!cpu_has_vx())
1004		return -ENODEV;
1005	if (target == current)
1006		save_user_fpu_regs();
1007
1008	rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
1009				target->thread.ufpu.vxrs + __NUM_VXRS_LOW, 0, -1);
1010	return rc;
1011}
1012
1013static int s390_system_call_get(struct task_struct *target,
1014				const struct user_regset *regset,
1015				struct membuf to)
1016{
1017	return membuf_store(&to, target->thread.system_call);
1018}
1019
1020static int s390_system_call_set(struct task_struct *target,
1021				const struct user_regset *regset,
1022				unsigned int pos, unsigned int count,
1023				const void *kbuf, const void __user *ubuf)
1024{
1025	unsigned int *data = &target->thread.system_call;
1026	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
1027				  data, 0, sizeof(unsigned int));
1028}
1029
1030static int s390_gs_cb_get(struct task_struct *target,
1031			  const struct user_regset *regset,
1032			  struct membuf to)
1033{
1034	struct gs_cb *data = target->thread.gs_cb;
1035
1036	if (!MACHINE_HAS_GS)
1037		return -ENODEV;
1038	if (!data)
1039		return -ENODATA;
1040	if (target == current)
1041		save_gs_cb(data);
1042	return membuf_write(&to, data, sizeof(struct gs_cb));
1043}
1044
1045static int s390_gs_cb_set(struct task_struct *target,
1046			  const struct user_regset *regset,
1047			  unsigned int pos, unsigned int count,
1048			  const void *kbuf, const void __user *ubuf)
1049{
1050	struct gs_cb gs_cb = { }, *data = NULL;
1051	int rc;
1052
1053	if (!MACHINE_HAS_GS)
1054		return -ENODEV;
1055	if (!target->thread.gs_cb) {
1056		data = kzalloc(sizeof(*data), GFP_KERNEL);
1057		if (!data)
1058			return -ENOMEM;
1059	}
1060	if (!target->thread.gs_cb)
1061		gs_cb.gsd = 25;
1062	else if (target == current)
1063		save_gs_cb(&gs_cb);
1064	else
1065		gs_cb = *target->thread.gs_cb;
1066	rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
1067				&gs_cb, 0, sizeof(gs_cb));
1068	if (rc) {
1069		kfree(data);
1070		return -EFAULT;
1071	}
1072	preempt_disable();
1073	if (!target->thread.gs_cb)
1074		target->thread.gs_cb = data;
1075	*target->thread.gs_cb = gs_cb;
1076	if (target == current) {
1077		local_ctl_set_bit(2, CR2_GUARDED_STORAGE_BIT);
1078		restore_gs_cb(target->thread.gs_cb);
1079	}
1080	preempt_enable();
1081	return rc;
1082}
1083
1084static int s390_gs_bc_get(struct task_struct *target,
1085			  const struct user_regset *regset,
1086			  struct membuf to)
1087{
1088	struct gs_cb *data = target->thread.gs_bc_cb;
1089
1090	if (!MACHINE_HAS_GS)
1091		return -ENODEV;
1092	if (!data)
1093		return -ENODATA;
1094	return membuf_write(&to, data, sizeof(struct gs_cb));
1095}
1096
1097static int s390_gs_bc_set(struct task_struct *target,
1098			  const struct user_regset *regset,
1099			  unsigned int pos, unsigned int count,
1100			  const void *kbuf, const void __user *ubuf)
1101{
1102	struct gs_cb *data = target->thread.gs_bc_cb;
1103
1104	if (!MACHINE_HAS_GS)
1105		return -ENODEV;
1106	if (!data) {
1107		data = kzalloc(sizeof(*data), GFP_KERNEL);
1108		if (!data)
1109			return -ENOMEM;
1110		target->thread.gs_bc_cb = data;
1111	}
1112	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
1113				  data, 0, sizeof(struct gs_cb));
1114}
1115
1116static bool is_ri_cb_valid(struct runtime_instr_cb *cb)
1117{
1118	return (cb->rca & 0x1f) == 0 &&
1119		(cb->roa & 0xfff) == 0 &&
1120		(cb->rla & 0xfff) == 0xfff &&
1121		cb->s == 1 &&
1122		cb->k == 1 &&
1123		cb->h == 0 &&
1124		cb->reserved1 == 0 &&
1125		cb->ps == 1 &&
1126		cb->qs == 0 &&
1127		cb->pc == 1 &&
1128		cb->qc == 0 &&
1129		cb->reserved2 == 0 &&
1130		cb->reserved3 == 0 &&
1131		cb->reserved4 == 0 &&
1132		cb->reserved5 == 0 &&
1133		cb->reserved6 == 0 &&
1134		cb->reserved7 == 0 &&
1135		cb->reserved8 == 0 &&
1136		cb->rla >= cb->roa &&
1137		cb->rca >= cb->roa &&
1138		cb->rca <= cb->rla+1 &&
1139		cb->m < 3;
1140}
1141
1142static int s390_runtime_instr_get(struct task_struct *target,
1143				const struct user_regset *regset,
1144				struct membuf to)
1145{
1146	struct runtime_instr_cb *data = target->thread.ri_cb;
1147
1148	if (!test_facility(64))
1149		return -ENODEV;
1150	if (!data)
1151		return -ENODATA;
1152
1153	return membuf_write(&to, data, sizeof(struct runtime_instr_cb));
1154}
1155
1156static int s390_runtime_instr_set(struct task_struct *target,
1157				  const struct user_regset *regset,
1158				  unsigned int pos, unsigned int count,
1159				  const void *kbuf, const void __user *ubuf)
1160{
1161	struct runtime_instr_cb ri_cb = { }, *data = NULL;
1162	int rc;
1163
1164	if (!test_facility(64))
1165		return -ENODEV;
1166
1167	if (!target->thread.ri_cb) {
1168		data = kzalloc(sizeof(*data), GFP_KERNEL);
1169		if (!data)
1170			return -ENOMEM;
1171	}
1172
1173	if (target->thread.ri_cb) {
1174		if (target == current)
1175			store_runtime_instr_cb(&ri_cb);
1176		else
1177			ri_cb = *target->thread.ri_cb;
1178	}
1179
1180	rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
1181				&ri_cb, 0, sizeof(struct runtime_instr_cb));
1182	if (rc) {
1183		kfree(data);
1184		return -EFAULT;
1185	}
1186
1187	if (!is_ri_cb_valid(&ri_cb)) {
1188		kfree(data);
1189		return -EINVAL;
1190	}
1191	/*
1192	 * Override access key in any case, since user space should
1193	 * not be able to set it, nor should it care about it.
1194	 */
1195	ri_cb.key = PAGE_DEFAULT_KEY >> 4;
1196	preempt_disable();
1197	if (!target->thread.ri_cb)
1198		target->thread.ri_cb = data;
1199	*target->thread.ri_cb = ri_cb;
1200	if (target == current)
1201		load_runtime_instr_cb(target->thread.ri_cb);
1202	preempt_enable();
1203
1204	return 0;
1205}
1206
1207static const struct user_regset s390_regsets[] = {
1208	{
1209		.core_note_type = NT_PRSTATUS,
1210		.n = sizeof(s390_regs) / sizeof(long),
1211		.size = sizeof(long),
1212		.align = sizeof(long),
1213		.regset_get = s390_regs_get,
1214		.set = s390_regs_set,
1215	},
1216	{
1217		.core_note_type = NT_PRFPREG,
1218		.n = sizeof(s390_fp_regs) / sizeof(long),
1219		.size = sizeof(long),
1220		.align = sizeof(long),
1221		.regset_get = s390_fpregs_get,
1222		.set = s390_fpregs_set,
1223	},
1224	{
1225		.core_note_type = NT_S390_SYSTEM_CALL,
1226		.n = 1,
1227		.size = sizeof(unsigned int),
1228		.align = sizeof(unsigned int),
1229		.regset_get = s390_system_call_get,
1230		.set = s390_system_call_set,
1231	},
1232	{
1233		.core_note_type = NT_S390_LAST_BREAK,
1234		.n = 1,
1235		.size = sizeof(long),
1236		.align = sizeof(long),
1237		.regset_get = s390_last_break_get,
1238		.set = s390_last_break_set,
1239	},
1240	{
1241		.core_note_type = NT_S390_TDB,
1242		.n = 1,
1243		.size = 256,
1244		.align = 1,
1245		.regset_get = s390_tdb_get,
1246		.set = s390_tdb_set,
1247	},
1248	{
1249		.core_note_type = NT_S390_VXRS_LOW,
1250		.n = __NUM_VXRS_LOW,
1251		.size = sizeof(__u64),
1252		.align = sizeof(__u64),
1253		.regset_get = s390_vxrs_low_get,
1254		.set = s390_vxrs_low_set,
1255	},
1256	{
1257		.core_note_type = NT_S390_VXRS_HIGH,
1258		.n = __NUM_VXRS_HIGH,
1259		.size = sizeof(__vector128),
1260		.align = sizeof(__vector128),
1261		.regset_get = s390_vxrs_high_get,
1262		.set = s390_vxrs_high_set,
1263	},
1264	{
1265		.core_note_type = NT_S390_GS_CB,
1266		.n = sizeof(struct gs_cb) / sizeof(__u64),
1267		.size = sizeof(__u64),
1268		.align = sizeof(__u64),
1269		.regset_get = s390_gs_cb_get,
1270		.set = s390_gs_cb_set,
1271	},
1272	{
1273		.core_note_type = NT_S390_GS_BC,
1274		.n = sizeof(struct gs_cb) / sizeof(__u64),
1275		.size = sizeof(__u64),
1276		.align = sizeof(__u64),
1277		.regset_get = s390_gs_bc_get,
1278		.set = s390_gs_bc_set,
1279	},
1280	{
1281		.core_note_type = NT_S390_RI_CB,
1282		.n = sizeof(struct runtime_instr_cb) / sizeof(__u64),
1283		.size = sizeof(__u64),
1284		.align = sizeof(__u64),
1285		.regset_get = s390_runtime_instr_get,
1286		.set = s390_runtime_instr_set,
1287	},
1288};
1289
1290static const struct user_regset_view user_s390_view = {
1291	.name = "s390x",
1292	.e_machine = EM_S390,
1293	.regsets = s390_regsets,
1294	.n = ARRAY_SIZE(s390_regsets)
1295};
1296
1297#ifdef CONFIG_COMPAT
1298static int s390_compat_regs_get(struct task_struct *target,
1299				const struct user_regset *regset,
1300				struct membuf to)
1301{
1302	unsigned n;
1303
1304	if (target == current)
1305		save_access_regs(target->thread.acrs);
1306
1307	for (n = 0; n < sizeof(s390_compat_regs); n += sizeof(compat_ulong_t))
1308		membuf_store(&to, __peek_user_compat(target, n));
1309	return 0;
1310}
1311
1312static int s390_compat_regs_set(struct task_struct *target,
1313				const struct user_regset *regset,
1314				unsigned int pos, unsigned int count,
1315				const void *kbuf, const void __user *ubuf)
1316{
1317	int rc = 0;
1318
1319	if (target == current)
1320		save_access_regs(target->thread.acrs);
1321
1322	if (kbuf) {
1323		const compat_ulong_t *k = kbuf;
1324		while (count > 0 && !rc) {
1325			rc = __poke_user_compat(target, pos, *k++);
1326			count -= sizeof(*k);
1327			pos += sizeof(*k);
1328		}
1329	} else {
1330		const compat_ulong_t  __user *u = ubuf;
1331		while (count > 0 && !rc) {
1332			compat_ulong_t word;
1333			rc = __get_user(word, u++);
1334			if (rc)
1335				break;
1336			rc = __poke_user_compat(target, pos, word);
1337			count -= sizeof(*u);
1338			pos += sizeof(*u);
1339		}
1340	}
1341
1342	if (rc == 0 && target == current)
1343		restore_access_regs(target->thread.acrs);
1344
1345	return rc;
1346}
1347
1348static int s390_compat_regs_high_get(struct task_struct *target,
1349				     const struct user_regset *regset,
1350				     struct membuf to)
1351{
1352	compat_ulong_t *gprs_high;
1353	int i;
1354
1355	gprs_high = (compat_ulong_t *)task_pt_regs(target)->gprs;
1356	for (i = 0; i < NUM_GPRS; i++, gprs_high += 2)
1357		membuf_store(&to, *gprs_high);
1358	return 0;
1359}
1360
1361static int s390_compat_regs_high_set(struct task_struct *target,
1362				     const struct user_regset *regset,
1363				     unsigned int pos, unsigned int count,
1364				     const void *kbuf, const void __user *ubuf)
1365{
1366	compat_ulong_t *gprs_high;
1367	int rc = 0;
1368
1369	gprs_high = (compat_ulong_t *)
1370		&task_pt_regs(target)->gprs[pos / sizeof(compat_ulong_t)];
1371	if (kbuf) {
1372		const compat_ulong_t *k = kbuf;
1373		while (count > 0) {
1374			*gprs_high = *k++;
1375			*gprs_high += 2;
1376			count -= sizeof(*k);
1377		}
1378	} else {
1379		const compat_ulong_t  __user *u = ubuf;
1380		while (count > 0 && !rc) {
1381			unsigned long word;
1382			rc = __get_user(word, u++);
1383			if (rc)
1384				break;
1385			*gprs_high = word;
1386			*gprs_high += 2;
1387			count -= sizeof(*u);
1388		}
1389	}
1390
1391	return rc;
1392}
1393
1394static int s390_compat_last_break_get(struct task_struct *target,
1395				      const struct user_regset *regset,
1396				      struct membuf to)
1397{
1398	compat_ulong_t last_break = target->thread.last_break;
1399
1400	return membuf_store(&to, (unsigned long)last_break);
1401}
1402
1403static int s390_compat_last_break_set(struct task_struct *target,
1404				      const struct user_regset *regset,
1405				      unsigned int pos, unsigned int count,
1406				      const void *kbuf, const void __user *ubuf)
1407{
1408	return 0;
1409}
1410
1411static const struct user_regset s390_compat_regsets[] = {
1412	{
1413		.core_note_type = NT_PRSTATUS,
1414		.n = sizeof(s390_compat_regs) / sizeof(compat_long_t),
1415		.size = sizeof(compat_long_t),
1416		.align = sizeof(compat_long_t),
1417		.regset_get = s390_compat_regs_get,
1418		.set = s390_compat_regs_set,
1419	},
1420	{
1421		.core_note_type = NT_PRFPREG,
1422		.n = sizeof(s390_fp_regs) / sizeof(compat_long_t),
1423		.size = sizeof(compat_long_t),
1424		.align = sizeof(compat_long_t),
1425		.regset_get = s390_fpregs_get,
1426		.set = s390_fpregs_set,
1427	},
1428	{
1429		.core_note_type = NT_S390_SYSTEM_CALL,
1430		.n = 1,
1431		.size = sizeof(compat_uint_t),
1432		.align = sizeof(compat_uint_t),
1433		.regset_get = s390_system_call_get,
1434		.set = s390_system_call_set,
1435	},
1436	{
1437		.core_note_type = NT_S390_LAST_BREAK,
1438		.n = 1,
1439		.size = sizeof(long),
1440		.align = sizeof(long),
1441		.regset_get = s390_compat_last_break_get,
1442		.set = s390_compat_last_break_set,
1443	},
1444	{
1445		.core_note_type = NT_S390_TDB,
1446		.n = 1,
1447		.size = 256,
1448		.align = 1,
1449		.regset_get = s390_tdb_get,
1450		.set = s390_tdb_set,
1451	},
1452	{
1453		.core_note_type = NT_S390_VXRS_LOW,
1454		.n = __NUM_VXRS_LOW,
1455		.size = sizeof(__u64),
1456		.align = sizeof(__u64),
1457		.regset_get = s390_vxrs_low_get,
1458		.set = s390_vxrs_low_set,
1459	},
1460	{
1461		.core_note_type = NT_S390_VXRS_HIGH,
1462		.n = __NUM_VXRS_HIGH,
1463		.size = sizeof(__vector128),
1464		.align = sizeof(__vector128),
1465		.regset_get = s390_vxrs_high_get,
1466		.set = s390_vxrs_high_set,
1467	},
1468	{
1469		.core_note_type = NT_S390_HIGH_GPRS,
1470		.n = sizeof(s390_compat_regs_high) / sizeof(compat_long_t),
1471		.size = sizeof(compat_long_t),
1472		.align = sizeof(compat_long_t),
1473		.regset_get = s390_compat_regs_high_get,
1474		.set = s390_compat_regs_high_set,
1475	},
1476	{
1477		.core_note_type = NT_S390_GS_CB,
1478		.n = sizeof(struct gs_cb) / sizeof(__u64),
1479		.size = sizeof(__u64),
1480		.align = sizeof(__u64),
1481		.regset_get = s390_gs_cb_get,
1482		.set = s390_gs_cb_set,
1483	},
1484	{
1485		.core_note_type = NT_S390_GS_BC,
1486		.n = sizeof(struct gs_cb) / sizeof(__u64),
1487		.size = sizeof(__u64),
1488		.align = sizeof(__u64),
1489		.regset_get = s390_gs_bc_get,
1490		.set = s390_gs_bc_set,
1491	},
1492	{
1493		.core_note_type = NT_S390_RI_CB,
1494		.n = sizeof(struct runtime_instr_cb) / sizeof(__u64),
1495		.size = sizeof(__u64),
1496		.align = sizeof(__u64),
1497		.regset_get = s390_runtime_instr_get,
1498		.set = s390_runtime_instr_set,
1499	},
1500};
1501
1502static const struct user_regset_view user_s390_compat_view = {
1503	.name = "s390",
1504	.e_machine = EM_S390,
1505	.regsets = s390_compat_regsets,
1506	.n = ARRAY_SIZE(s390_compat_regsets)
1507};
1508#endif
1509
1510const struct user_regset_view *task_user_regset_view(struct task_struct *task)
1511{
1512#ifdef CONFIG_COMPAT
1513	if (test_tsk_thread_flag(task, TIF_31BIT))
1514		return &user_s390_compat_view;
1515#endif
1516	return &user_s390_view;
1517}
1518
1519static const char *gpr_names[NUM_GPRS] = {
1520	"r0", "r1",  "r2",  "r3",  "r4",  "r5",  "r6",  "r7",
1521	"r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
1522};
1523
1524unsigned long regs_get_register(struct pt_regs *regs, unsigned int offset)
1525{
1526	if (offset >= NUM_GPRS)
1527		return 0;
1528	return regs->gprs[offset];
1529}
1530
1531int regs_query_register_offset(const char *name)
1532{
1533	unsigned long offset;
1534
1535	if (!name || *name != 'r')
1536		return -EINVAL;
1537	if (kstrtoul(name + 1, 10, &offset))
1538		return -EINVAL;
1539	if (offset >= NUM_GPRS)
1540		return -EINVAL;
1541	return offset;
1542}
1543
1544const char *regs_query_register_name(unsigned int offset)
1545{
1546	if (offset >= NUM_GPRS)
1547		return NULL;
1548	return gpr_names[offset];
1549}
1550
1551static int regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
1552{
1553	unsigned long ksp = kernel_stack_pointer(regs);
1554
1555	return (addr & ~(THREAD_SIZE - 1)) == (ksp & ~(THREAD_SIZE - 1));
1556}
1557
1558/**
1559 * regs_get_kernel_stack_nth() - get Nth entry of the stack
1560 * @regs:pt_regs which contains kernel stack pointer.
1561 * @n:stack entry number.
1562 *
1563 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
1564 * is specifined by @regs. If the @n th entry is NOT in the kernel stack,
1565 * this returns 0.
1566 */
1567unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
1568{
1569	unsigned long addr;
1570
1571	addr = kernel_stack_pointer(regs) + n * sizeof(long);
1572	if (!regs_within_kernel_stack(regs, addr))
1573		return 0;
1574	return *(unsigned long *)addr;
1575}