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v4.6
  1/*
  2 *  linux/arch/parisc/kernel/signal.c: Architecture-specific signal
  3 *  handling support.
  4 *
  5 *  Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
  6 *  Copyright (C) 2000 Linuxcare, Inc.
  7 *
  8 *  Based on the ia64, i386, and alpha versions.
  9 *
 10 *  Like the IA-64, we are a recent enough port (we are *starting*
 11 *  with glibc2.2) that we do not need to support the old non-realtime
 12 *  Linux signals.  Therefore we don't.
 
 13 */
 14
 15#include <linux/sched.h>
 16#include <linux/mm.h>
 17#include <linux/smp.h>
 18#include <linux/kernel.h>
 19#include <linux/signal.h>
 20#include <linux/errno.h>
 21#include <linux/wait.h>
 22#include <linux/ptrace.h>
 23#include <linux/tracehook.h>
 24#include <linux/unistd.h>
 25#include <linux/stddef.h>
 26#include <linux/compat.h>
 27#include <linux/elf.h>
 28#include <asm/ucontext.h>
 29#include <asm/rt_sigframe.h>
 30#include <asm/uaccess.h>
 31#include <asm/pgalloc.h>
 32#include <asm/cacheflush.h>
 33#include <asm/asm-offsets.h>
 34
 35#ifdef CONFIG_COMPAT
 36#include "signal32.h"
 37#endif
 38
 39#define DEBUG_SIG 0 
 40#define DEBUG_SIG_LEVEL 2
 41
 42#if DEBUG_SIG
 43#define DBG(LEVEL, ...) \
 44        ((DEBUG_SIG_LEVEL >= LEVEL) \
 45	? printk(__VA_ARGS__) : (void) 0)
 46#else
 47#define DBG(LEVEL, ...)
 48#endif
 49	
 50/* gcc will complain if a pointer is cast to an integer of different
 51 * size.  If you really need to do this (and we do for an ELF32 user
 52 * application in an ELF64 kernel) then you have to do a cast to an
 53 * integer of the same size first.  The A() macro accomplishes
 54 * this. */
 55#define A(__x)	((unsigned long)(__x))
 56
 57/*
 
 
 
 
 
 
 
 58 * Do a signal return - restore sigcontext.
 59 */
 60
 61/* Trampoline for calling rt_sigreturn() */
 62#define INSN_LDI_R25_0	 0x34190000 /* ldi  0,%r25 (in_syscall=0) */
 63#define INSN_LDI_R25_1	 0x34190002 /* ldi  1,%r25 (in_syscall=1) */
 64#define INSN_LDI_R20	 0x3414015a /* ldi  __NR_rt_sigreturn,%r20 */
 65#define INSN_BLE_SR2_R0  0xe4008200 /* be,l 0x100(%sr2,%r0),%sr0,%r31 */
 66#define INSN_NOP	 0x08000240 /* nop */
 67/* For debugging */
 68#define INSN_DIE_HORRIBLY 0x68000ccc /* stw %r0,0x666(%sr0,%r0) */
 69
 70static long
 71restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
 72{
 73	long err = 0;
 74
 75	err |= __copy_from_user(regs->gr, sc->sc_gr, sizeof(regs->gr));
 76	err |= __copy_from_user(regs->fr, sc->sc_fr, sizeof(regs->fr));
 77	err |= __copy_from_user(regs->iaoq, sc->sc_iaoq, sizeof(regs->iaoq));
 78	err |= __copy_from_user(regs->iasq, sc->sc_iasq, sizeof(regs->iasq));
 79	err |= __get_user(regs->sar, &sc->sc_sar);
 80	DBG(2,"restore_sigcontext: iaoq is %#lx / %#lx\n",
 81			regs->iaoq[0],regs->iaoq[1]);
 82	DBG(2,"restore_sigcontext: r28 is %ld\n", regs->gr[28]);
 83	return err;
 84}
 85
 86void
 87sys_rt_sigreturn(struct pt_regs *regs, int in_syscall)
 88{
 89	struct rt_sigframe __user *frame;
 90	sigset_t set;
 91	unsigned long usp = (regs->gr[30] & ~(0x01UL));
 92	unsigned long sigframe_size = PARISC_RT_SIGFRAME_SIZE;
 93#ifdef CONFIG_64BIT
 94	compat_sigset_t compat_set;
 95	struct compat_rt_sigframe __user * compat_frame;
 96	
 97	if (is_compat_task())
 98		sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
 99#endif
100
101	current->restart_block.fn = do_no_restart_syscall;
102
103	/* Unwind the user stack to get the rt_sigframe structure. */
104	frame = (struct rt_sigframe __user *)
105		(usp - sigframe_size);
106	DBG(2,"sys_rt_sigreturn: frame is %p\n", frame);
107
108	regs->orig_r28 = 1; /* no restarts for sigreturn */
109
110#ifdef CONFIG_64BIT
111	compat_frame = (struct compat_rt_sigframe __user *)frame;
112	
113	if (is_compat_task()) {
114		DBG(2,"sys_rt_sigreturn: ELF32 process.\n");
115		if (__copy_from_user(&compat_set, &compat_frame->uc.uc_sigmask, sizeof(compat_set)))
116			goto give_sigsegv;
117		sigset_32to64(&set,&compat_set);
118	} else
119#endif
120	{
121		if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
122			goto give_sigsegv;
123	}
124		
125	set_current_blocked(&set);
126
127	/* Good thing we saved the old gr[30], eh? */
128#ifdef CONFIG_64BIT
129	if (is_compat_task()) {
130		DBG(1,"sys_rt_sigreturn: compat_frame->uc.uc_mcontext 0x%p\n",
131				&compat_frame->uc.uc_mcontext);
132// FIXME: Load upper half from register file
133		if (restore_sigcontext32(&compat_frame->uc.uc_mcontext, 
134					&compat_frame->regs, regs))
135			goto give_sigsegv;
136		DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n", 
137				usp, &compat_frame->uc.uc_stack);
138		if (compat_restore_altstack(&compat_frame->uc.uc_stack))
139			goto give_sigsegv;
140	} else
141#endif
142	{
143		DBG(1,"sys_rt_sigreturn: frame->uc.uc_mcontext 0x%p\n",
144				&frame->uc.uc_mcontext);
145		if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
146			goto give_sigsegv;
147		DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n", 
148				usp, &frame->uc.uc_stack);
149		if (restore_altstack(&frame->uc.uc_stack))
150			goto give_sigsegv;
151	}
152		
153
154
155	/* If we are on the syscall path IAOQ will not be restored, and
156	 * if we are on the interrupt path we must not corrupt gr31.
157	 */
158	if (in_syscall)
159		regs->gr[31] = regs->iaoq[0];
160#if DEBUG_SIG
161	DBG(1,"sys_rt_sigreturn: returning to %#lx, DUMPING REGS:\n", regs->iaoq[0]);
162	show_regs(regs);
163#endif
164	return;
165
166give_sigsegv:
167	DBG(1,"sys_rt_sigreturn: Sending SIGSEGV\n");
168	force_sig(SIGSEGV, current);
169	return;
170}
171
172/*
173 * Set up a signal frame.
174 */
175
176static inline void __user *
177get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
178{
179	/*FIXME: ELF32 vs. ELF64 has different frame_size, but since we
180	  don't use the parameter it doesn't matter */
181
182	DBG(1,"get_sigframe: ka = %#lx, sp = %#lx, frame_size = %#lx\n",
183			(unsigned long)ka, sp, frame_size);
184	
185	/* Align alternate stack and reserve 64 bytes for the signal
186	   handler's frame marker.  */
187	if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
188		sp = (current->sas_ss_sp + 0x7f) & ~0x3f; /* Stacks grow up! */
189
190	DBG(1,"get_sigframe: Returning sp = %#lx\n", (unsigned long)sp);
191	return (void __user *) sp; /* Stacks grow up.  Fun. */
192}
193
194static long
195setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, int in_syscall)
196		 
197{
198	unsigned long flags = 0;
199	long err = 0;
200
201	if (on_sig_stack((unsigned long) sc))
202		flags |= PARISC_SC_FLAG_ONSTACK;
203	if (in_syscall) {
204		flags |= PARISC_SC_FLAG_IN_SYSCALL;
205		/* regs->iaoq is undefined in the syscall return path */
206		err |= __put_user(regs->gr[31], &sc->sc_iaoq[0]);
207		err |= __put_user(regs->gr[31]+4, &sc->sc_iaoq[1]);
208		err |= __put_user(regs->sr[3], &sc->sc_iasq[0]);
209		err |= __put_user(regs->sr[3], &sc->sc_iasq[1]);
210		DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (in syscall)\n",
211			regs->gr[31], regs->gr[31]+4);
212	} else {
213		err |= __copy_to_user(sc->sc_iaoq, regs->iaoq, sizeof(regs->iaoq));
214		err |= __copy_to_user(sc->sc_iasq, regs->iasq, sizeof(regs->iasq));
215		DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (not in syscall)\n", 
216			regs->iaoq[0], regs->iaoq[1]);
217	}
218
219	err |= __put_user(flags, &sc->sc_flags);
220	err |= __copy_to_user(sc->sc_gr, regs->gr, sizeof(regs->gr));
221	err |= __copy_to_user(sc->sc_fr, regs->fr, sizeof(regs->fr));
222	err |= __put_user(regs->sar, &sc->sc_sar);
223	DBG(1,"setup_sigcontext: r28 is %ld\n", regs->gr[28]);
224
225	return err;
226}
227
228static long
229setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
230	       int in_syscall)
231{
232	struct rt_sigframe __user *frame;
233	unsigned long rp, usp;
234	unsigned long haddr, sigframe_size;
235	int err = 0;
236#ifdef CONFIG_64BIT
 
237	struct compat_rt_sigframe __user * compat_frame;
238	compat_sigset_t compat_set;
239#endif
240	
241	usp = (regs->gr[30] & ~(0x01UL));
242	/*FIXME: frame_size parameter is unused, remove it. */
243	frame = get_sigframe(&ksig->ka, usp, sizeof(*frame));
244
245	DBG(1,"SETUP_RT_FRAME: START\n");
246	DBG(1,"setup_rt_frame: frame %p info %p\n", frame, ksig->info);
247
248	
249#ifdef CONFIG_64BIT
250
251	compat_frame = (struct compat_rt_sigframe __user *)frame;
252	
253	if (is_compat_task()) {
254		DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &compat_frame->info);
255		err |= copy_siginfo_to_user32(&compat_frame->info, &ksig->info);
256		err |= __compat_save_altstack( &compat_frame->uc.uc_stack, regs->gr[30]);
 
 
 
 
 
 
 
 
257		DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &compat_frame->uc);
258		DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &compat_frame->uc.uc_mcontext);
259		err |= setup_sigcontext32(&compat_frame->uc.uc_mcontext, 
260					&compat_frame->regs, regs, in_syscall);
261		sigset_64to32(&compat_set,set);
262		err |= __copy_to_user(&compat_frame->uc.uc_sigmask, &compat_set, sizeof(compat_set));
263	} else
264#endif
265	{	
266		DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &frame->info);
267		err |= copy_siginfo_to_user(&frame->info, &ksig->info);
268		err |= __save_altstack(&frame->uc.uc_stack, regs->gr[30]);
 
 
 
269		DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &frame->uc);
270		DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &frame->uc.uc_mcontext);
271		err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, in_syscall);
272		/* FIXME: Should probably be converted as well for the compat case */
273		err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
274	}
275	
276	if (err)
277		return -EFAULT;
278
279	/* Set up to return from userspace.  If provided, use a stub
280	   already in userspace. The first words of tramp are used to
281	   save the previous sigrestartblock trampoline that might be
282	   on the stack. We start the sigreturn trampoline at 
283	   SIGRESTARTBLOCK_TRAMP+X. */
284	err |= __put_user(in_syscall ? INSN_LDI_R25_1 : INSN_LDI_R25_0,
285			&frame->tramp[SIGRESTARTBLOCK_TRAMP+0]);
286	err |= __put_user(INSN_LDI_R20, 
287			&frame->tramp[SIGRESTARTBLOCK_TRAMP+1]);
288	err |= __put_user(INSN_BLE_SR2_R0, 
289			&frame->tramp[SIGRESTARTBLOCK_TRAMP+2]);
290	err |= __put_user(INSN_NOP, &frame->tramp[SIGRESTARTBLOCK_TRAMP+3]);
291
292#if DEBUG_SIG
293	/* Assert that we're flushing in the correct space... */
294	{
295		unsigned long sid;
296		asm ("mfsp %%sr3,%0" : "=r" (sid));
297		DBG(1,"setup_rt_frame: Flushing 64 bytes at space %#x offset %p\n",
298		       sid, frame->tramp);
299	}
300#endif
301
302	flush_user_dcache_range((unsigned long) &frame->tramp[0],
303			   (unsigned long) &frame->tramp[TRAMP_SIZE]);
304	flush_user_icache_range((unsigned long) &frame->tramp[0],
305			   (unsigned long) &frame->tramp[TRAMP_SIZE]);
306
307	/* TRAMP Words 0-4, Length 5 = SIGRESTARTBLOCK_TRAMP
308	 * TRAMP Words 5-9, Length 4 = SIGRETURN_TRAMP
309	 * So the SIGRETURN_TRAMP is at the end of SIGRESTARTBLOCK_TRAMP
310	 */
311	rp = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP];
312
313	if (err)
314		return -EFAULT;
315
316	haddr = A(ksig->ka.sa.sa_handler);
317	/* The sa_handler may be a pointer to a function descriptor */
318#ifdef CONFIG_64BIT
319	if (is_compat_task()) {
320#endif
321		if (haddr & PA_PLABEL_FDESC) {
322			Elf32_Fdesc fdesc;
323			Elf32_Fdesc __user *ufdesc = (Elf32_Fdesc __user *)A(haddr & ~3);
324
325			err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
326
327			if (err)
328				return -EFAULT;
329
330			haddr = fdesc.addr;
331			regs->gr[19] = fdesc.gp;
332		}
333#ifdef CONFIG_64BIT
334	} else {
335		Elf64_Fdesc fdesc;
336		Elf64_Fdesc __user *ufdesc = (Elf64_Fdesc __user *)A(haddr & ~3);
337		
338		err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
339		
340		if (err)
341			return -EFAULT;
342		
343		haddr = fdesc.addr;
344		regs->gr[19] = fdesc.gp;
345		DBG(1,"setup_rt_frame: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n",
346		     haddr, regs->gr[19], in_syscall);
347	}
348#endif
349
350	/* The syscall return path will create IAOQ values from r31.
351	 */
352	sigframe_size = PARISC_RT_SIGFRAME_SIZE;
353#ifdef CONFIG_64BIT
354	if (is_compat_task())
355		sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
356#endif
357	if (in_syscall) {
358		regs->gr[31] = haddr;
359#ifdef CONFIG_64BIT
360		if (!test_thread_flag(TIF_32BIT))
361			sigframe_size |= 1;
362#endif
363	} else {
364		unsigned long psw = USER_PSW;
365#ifdef CONFIG_64BIT
366		if (!test_thread_flag(TIF_32BIT))
367			psw |= PSW_W;
368#endif
369
370		/* If we are singlestepping, arrange a trap to be delivered
371		   when we return to userspace. Note the semantics -- we
372		   should trap before the first insn in the handler is
373		   executed. Ref:
374			http://sources.redhat.com/ml/gdb/2004-11/msg00245.html
375		 */
376		if (pa_psw(current)->r) {
377			pa_psw(current)->r = 0;
378			psw |= PSW_R;
379			mtctl(-1, 0);
380		}
381
382		regs->gr[0] = psw;
383		regs->iaoq[0] = haddr | 3;
384		regs->iaoq[1] = regs->iaoq[0] + 4;
385	}
386
387	regs->gr[2]  = rp;                /* userland return pointer */
388	regs->gr[26] = ksig->sig;               /* signal number */
389	
390#ifdef CONFIG_64BIT
391	if (is_compat_task()) {
392		regs->gr[25] = A(&compat_frame->info); /* siginfo pointer */
393		regs->gr[24] = A(&compat_frame->uc);   /* ucontext pointer */
394	} else
395#endif
396	{		
397		regs->gr[25] = A(&frame->info); /* siginfo pointer */
398		regs->gr[24] = A(&frame->uc);   /* ucontext pointer */
399	}
400	
401	DBG(1,"setup_rt_frame: making sigreturn frame: %#lx + %#lx = %#lx\n",
402	       regs->gr[30], sigframe_size,
403	       regs->gr[30] + sigframe_size);
404	/* Raise the user stack pointer to make a proper call frame. */
405	regs->gr[30] = (A(frame) + sigframe_size);
406
407
408	DBG(1,"setup_rt_frame: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n",
409	       current->comm, current->pid, frame, regs->gr[30],
410	       regs->iaoq[0], regs->iaoq[1], rp);
411
 
 
 
 
 
412	return 0;
413}
414
415/*
416 * OK, we're invoking a handler.
417 */	
418
419static void
420handle_signal(struct ksignal *ksig, struct pt_regs *regs, int in_syscall)
 
421{
422	int ret;
423	sigset_t *oldset = sigmask_to_save();
424
425	DBG(1,"handle_signal: sig=%ld, ka=%p, info=%p, oldset=%p, regs=%p\n",
426	       ksig->sig, ksig->ka, ksig->info, oldset, regs);
427	
428	/* Set up the stack frame */
429	ret = setup_rt_frame(ksig, oldset, regs, in_syscall);
 
430
431	signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP) ||
432			  test_thread_flag(TIF_BLOCKSTEP));
 
433
434	DBG(1,KERN_DEBUG "do_signal: Exit (success), regs->gr[28] = %ld\n",
435		regs->gr[28]);
436}
437
438/*
439 * Check how the syscall number gets loaded into %r20 within
440 * the delay branch in userspace and adjust as needed.
441 */
442
443static void check_syscallno_in_delay_branch(struct pt_regs *regs)
444{
445	u32 opcode, source_reg;
446	u32 __user *uaddr;
447	int err;
448
449	/* Usually we don't have to restore %r20 (the system call number)
450	 * because it gets loaded in the delay slot of the branch external
451	 * instruction via the ldi instruction.
452	 * In some cases a register-to-register copy instruction might have
453	 * been used instead, in which case we need to copy the syscall
454	 * number into the source register before returning to userspace.
455	 */
456
457	/* A syscall is just a branch, so all we have to do is fiddle the
458	 * return pointer so that the ble instruction gets executed again.
459	 */
460	regs->gr[31] -= 8; /* delayed branching */
461
462	/* Get assembler opcode of code in delay branch */
463	uaddr = (unsigned int *) ((regs->gr[31] & ~3) + 4);
464	err = get_user(opcode, uaddr);
465	if (err)
466		return;
467
468	/* Check if delay branch uses "ldi int,%r20" */
469	if ((opcode & 0xffff0000) == 0x34140000)
470		return;	/* everything ok, just return */
471
472	/* Check if delay branch uses "nop" */
473	if (opcode == INSN_NOP)
474		return;
475
476	/* Check if delay branch uses "copy %rX,%r20" */
477	if ((opcode & 0xffe0ffff) == 0x08000254) {
478		source_reg = (opcode >> 16) & 31;
479		regs->gr[source_reg] = regs->gr[20];
480		return;
481	}
482
483	pr_warn("syscall restart: %s (pid %d): unexpected opcode 0x%08x\n",
484		current->comm, task_pid_nr(current), opcode);
485}
486
487static inline void
488syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
489{
490	if (regs->orig_r28)
491		return;
492	regs->orig_r28 = 1; /* no more restarts */
493	/* Check the return code */
494	switch (regs->gr[28]) {
495	case -ERESTART_RESTARTBLOCK:
496	case -ERESTARTNOHAND:
497		DBG(1,"ERESTARTNOHAND: returning -EINTR\n");
498		regs->gr[28] = -EINTR;
499		break;
500
501	case -ERESTARTSYS:
502		if (!(ka->sa.sa_flags & SA_RESTART)) {
503			DBG(1,"ERESTARTSYS: putting -EINTR\n");
504			regs->gr[28] = -EINTR;
505			break;
506		}
507		/* fallthrough */
508	case -ERESTARTNOINTR:
509		check_syscallno_in_delay_branch(regs);
 
 
 
 
 
510		break;
511	}
512}
513
514static inline void
515insert_restart_trampoline(struct pt_regs *regs)
516{
517	if (regs->orig_r28)
518		return;
519	regs->orig_r28 = 1; /* no more restarts */
520	switch(regs->gr[28]) {
521	case -ERESTART_RESTARTBLOCK: {
522		/* Restart the system call - no handlers present */
523		unsigned int *usp = (unsigned int *)regs->gr[30];
524		unsigned long start = (unsigned long) &usp[2];
525		unsigned long end  = (unsigned long) &usp[5];
526		long err = 0;
527
528		/* Setup a trampoline to restart the syscall
529		 * with __NR_restart_syscall
530		 *
531		 *  0: <return address (orig r31)>
532		 *  4: <2nd half for 64-bit>
533		 *  8: ldw 0(%sp), %r31
534		 * 12: be 0x100(%sr2, %r0)
535		 * 16: ldi __NR_restart_syscall, %r20
536		 */
537#ifdef CONFIG_64BIT
538		err |= put_user(regs->gr[31] >> 32, &usp[0]);
539		err |= put_user(regs->gr[31] & 0xffffffff, &usp[1]);
540		err |= put_user(0x0fc010df, &usp[2]);
541#else
542		err |= put_user(regs->gr[31], &usp[0]);
543		err |= put_user(0x0fc0109f, &usp[2]);
544#endif
545		err |= put_user(0xe0008200, &usp[3]);
546		err |= put_user(0x34140000, &usp[4]);
547
548		WARN_ON(err);
549
550		/* flush data/instruction cache for new insns */
551		flush_user_dcache_range(start, end);
552		flush_user_icache_range(start, end);
 
 
553
554		regs->gr[31] = regs->gr[30] + 8;
 
 
 
555		return;
556	}
557	case -ERESTARTNOHAND:
558	case -ERESTARTSYS:
559	case -ERESTARTNOINTR:
560		check_syscallno_in_delay_branch(regs);
 
 
 
 
 
 
 
 
561		return;
 
562	default:
563		break;
564	}
565}
566
567/*
568 * Note that 'init' is a special process: it doesn't get signals it doesn't
569 * want to handle. Thus you cannot kill init even with a SIGKILL even by
570 * mistake.
571 *
572 * We need to be able to restore the syscall arguments (r21-r26) to
573 * restart syscalls.  Thus, the syscall path should save them in the
574 * pt_regs structure (it's okay to do so since they are caller-save
575 * registers).  As noted below, the syscall number gets restored for
576 * us due to the magic of delayed branching.
577 */
578asmlinkage void
579do_signal(struct pt_regs *regs, long in_syscall)
580{
581	struct ksignal ksig;
 
 
582
583	DBG(1,"\ndo_signal: regs=0x%p, sr7 %#lx, in_syscall=%d\n",
584	       regs, regs->sr[7], in_syscall);
585
586	if (get_signal(&ksig)) {
587		DBG(3,"do_signal: signr = %d, regs->gr[28] = %ld\n", signr, regs->gr[28]);
 
 
 
 
 
 
 
 
 
 
 
588		/* Restart a system call if necessary. */
589		if (in_syscall)
590			syscall_restart(regs, &ksig.ka);
591
592		handle_signal(&ksig, regs, in_syscall);
593		return;
 
 
 
594	}
 
595
596	/* Did we come from a system call? */
597	if (in_syscall)
598		insert_restart_trampoline(regs);
599	
600	DBG(1,"do_signal: Exit (not delivered), regs->gr[28] = %ld\n", 
601		regs->gr[28]);
602
603	restore_saved_sigmask();
604}
605
606void do_notify_resume(struct pt_regs *regs, long in_syscall)
607{
608	if (test_thread_flag(TIF_SIGPENDING))
609		do_signal(regs, in_syscall);
610
611	if (test_thread_flag(TIF_NOTIFY_RESUME)) {
612		clear_thread_flag(TIF_NOTIFY_RESUME);
613		tracehook_notify_resume(regs);
614	}
615}
v3.5.6
  1/*
  2 *  linux/arch/parisc/kernel/signal.c: Architecture-specific signal
  3 *  handling support.
  4 *
  5 *  Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
  6 *  Copyright (C) 2000 Linuxcare, Inc.
  7 *
  8 *  Based on the ia64, i386, and alpha versions.
  9 *
 10 *  Like the IA-64, we are a recent enough port (we are *starting*
 11 *  with glibc2.2) that we do not need to support the old non-realtime
 12 *  Linux signals.  Therefore we don't.  HP/UX signals will go in
 13 *  arch/parisc/hpux/signal.c when we figure out how to do them.
 14 */
 15
 16#include <linux/sched.h>
 17#include <linux/mm.h>
 18#include <linux/smp.h>
 19#include <linux/kernel.h>
 20#include <linux/signal.h>
 21#include <linux/errno.h>
 22#include <linux/wait.h>
 23#include <linux/ptrace.h>
 24#include <linux/tracehook.h>
 25#include <linux/unistd.h>
 26#include <linux/stddef.h>
 27#include <linux/compat.h>
 28#include <linux/elf.h>
 29#include <asm/ucontext.h>
 30#include <asm/rt_sigframe.h>
 31#include <asm/uaccess.h>
 32#include <asm/pgalloc.h>
 33#include <asm/cacheflush.h>
 34#include <asm/asm-offsets.h>
 35
 36#ifdef CONFIG_COMPAT
 37#include "signal32.h"
 38#endif
 39
 40#define DEBUG_SIG 0 
 41#define DEBUG_SIG_LEVEL 2
 42
 43#if DEBUG_SIG
 44#define DBG(LEVEL, ...) \
 45        ((DEBUG_SIG_LEVEL >= LEVEL) \
 46	? printk(__VA_ARGS__) : (void) 0)
 47#else
 48#define DBG(LEVEL, ...)
 49#endif
 50	
 51/* gcc will complain if a pointer is cast to an integer of different
 52 * size.  If you really need to do this (and we do for an ELF32 user
 53 * application in an ELF64 kernel) then you have to do a cast to an
 54 * integer of the same size first.  The A() macro accomplishes
 55 * this. */
 56#define A(__x)	((unsigned long)(__x))
 57
 58/*
 59 * Atomically swap in the new signal mask, and wait for a signal.
 60 */
 61#ifdef CONFIG_64BIT
 62#include "sys32.h"
 63#endif
 64
 65/*
 66 * Do a signal return - restore sigcontext.
 67 */
 68
 69/* Trampoline for calling rt_sigreturn() */
 70#define INSN_LDI_R25_0	 0x34190000 /* ldi  0,%r25 (in_syscall=0) */
 71#define INSN_LDI_R25_1	 0x34190002 /* ldi  1,%r25 (in_syscall=1) */
 72#define INSN_LDI_R20	 0x3414015a /* ldi  __NR_rt_sigreturn,%r20 */
 73#define INSN_BLE_SR2_R0  0xe4008200 /* be,l 0x100(%sr2,%r0),%sr0,%r31 */
 74#define INSN_NOP	 0x08000240 /* nop */
 75/* For debugging */
 76#define INSN_DIE_HORRIBLY 0x68000ccc /* stw %r0,0x666(%sr0,%r0) */
 77
 78static long
 79restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
 80{
 81	long err = 0;
 82
 83	err |= __copy_from_user(regs->gr, sc->sc_gr, sizeof(regs->gr));
 84	err |= __copy_from_user(regs->fr, sc->sc_fr, sizeof(regs->fr));
 85	err |= __copy_from_user(regs->iaoq, sc->sc_iaoq, sizeof(regs->iaoq));
 86	err |= __copy_from_user(regs->iasq, sc->sc_iasq, sizeof(regs->iasq));
 87	err |= __get_user(regs->sar, &sc->sc_sar);
 88	DBG(2,"restore_sigcontext: iaoq is 0x%#lx / 0x%#lx\n", 
 89			regs->iaoq[0],regs->iaoq[1]);
 90	DBG(2,"restore_sigcontext: r28 is %ld\n", regs->gr[28]);
 91	return err;
 92}
 93
 94void
 95sys_rt_sigreturn(struct pt_regs *regs, int in_syscall)
 96{
 97	struct rt_sigframe __user *frame;
 98	sigset_t set;
 99	unsigned long usp = (regs->gr[30] & ~(0x01UL));
100	unsigned long sigframe_size = PARISC_RT_SIGFRAME_SIZE;
101#ifdef CONFIG_64BIT
102	compat_sigset_t compat_set;
103	struct compat_rt_sigframe __user * compat_frame;
104	
105	if (is_compat_task())
106		sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
107#endif
108
109	current_thread_info()->restart_block.fn = do_no_restart_syscall;
110
111	/* Unwind the user stack to get the rt_sigframe structure. */
112	frame = (struct rt_sigframe __user *)
113		(usp - sigframe_size);
114	DBG(2,"sys_rt_sigreturn: frame is %p\n", frame);
115
 
 
116#ifdef CONFIG_64BIT
117	compat_frame = (struct compat_rt_sigframe __user *)frame;
118	
119	if (is_compat_task()) {
120		DBG(2,"sys_rt_sigreturn: ELF32 process.\n");
121		if (__copy_from_user(&compat_set, &compat_frame->uc.uc_sigmask, sizeof(compat_set)))
122			goto give_sigsegv;
123		sigset_32to64(&set,&compat_set);
124	} else
125#endif
126	{
127		if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
128			goto give_sigsegv;
129	}
130		
131	set_current_blocked(&set);
132
133	/* Good thing we saved the old gr[30], eh? */
134#ifdef CONFIG_64BIT
135	if (is_compat_task()) {
136		DBG(1,"sys_rt_sigreturn: compat_frame->uc.uc_mcontext 0x%p\n",
137				&compat_frame->uc.uc_mcontext);
138// FIXME: Load upper half from register file
139		if (restore_sigcontext32(&compat_frame->uc.uc_mcontext, 
140					&compat_frame->regs, regs))
141			goto give_sigsegv;
142		DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n", 
143				usp, &compat_frame->uc.uc_stack);
144		if (do_sigaltstack32(&compat_frame->uc.uc_stack, NULL, usp) == -EFAULT)
145			goto give_sigsegv;
146	} else
147#endif
148	{
149		DBG(1,"sys_rt_sigreturn: frame->uc.uc_mcontext 0x%p\n",
150				&frame->uc.uc_mcontext);
151		if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
152			goto give_sigsegv;
153		DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n", 
154				usp, &frame->uc.uc_stack);
155		if (do_sigaltstack(&frame->uc.uc_stack, NULL, usp) == -EFAULT)
156			goto give_sigsegv;
157	}
158		
159
160
161	/* If we are on the syscall path IAOQ will not be restored, and
162	 * if we are on the interrupt path we must not corrupt gr31.
163	 */
164	if (in_syscall)
165		regs->gr[31] = regs->iaoq[0];
166#if DEBUG_SIG
167	DBG(1,"sys_rt_sigreturn: returning to %#lx, DUMPING REGS:\n", regs->iaoq[0]);
168	show_regs(regs);
169#endif
170	return;
171
172give_sigsegv:
173	DBG(1,"sys_rt_sigreturn: Sending SIGSEGV\n");
174	force_sig(SIGSEGV, current);
175	return;
176}
177
178/*
179 * Set up a signal frame.
180 */
181
182static inline void __user *
183get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
184{
185	/*FIXME: ELF32 vs. ELF64 has different frame_size, but since we
186	  don't use the parameter it doesn't matter */
187
188	DBG(1,"get_sigframe: ka = %#lx, sp = %#lx, frame_size = %#lx\n",
189			(unsigned long)ka, sp, frame_size);
190	
 
 
191	if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
192		sp = current->sas_ss_sp; /* Stacks grow up! */
193
194	DBG(1,"get_sigframe: Returning sp = %#lx\n", (unsigned long)sp);
195	return (void __user *) sp; /* Stacks grow up.  Fun. */
196}
197
198static long
199setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, int in_syscall)
200		 
201{
202	unsigned long flags = 0;
203	long err = 0;
204
205	if (on_sig_stack((unsigned long) sc))
206		flags |= PARISC_SC_FLAG_ONSTACK;
207	if (in_syscall) {
208		flags |= PARISC_SC_FLAG_IN_SYSCALL;
209		/* regs->iaoq is undefined in the syscall return path */
210		err |= __put_user(regs->gr[31], &sc->sc_iaoq[0]);
211		err |= __put_user(regs->gr[31]+4, &sc->sc_iaoq[1]);
212		err |= __put_user(regs->sr[3], &sc->sc_iasq[0]);
213		err |= __put_user(regs->sr[3], &sc->sc_iasq[1]);
214		DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (in syscall)\n",
215			regs->gr[31], regs->gr[31]+4);
216	} else {
217		err |= __copy_to_user(sc->sc_iaoq, regs->iaoq, sizeof(regs->iaoq));
218		err |= __copy_to_user(sc->sc_iasq, regs->iasq, sizeof(regs->iasq));
219		DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (not in syscall)\n", 
220			regs->iaoq[0], regs->iaoq[1]);
221	}
222
223	err |= __put_user(flags, &sc->sc_flags);
224	err |= __copy_to_user(sc->sc_gr, regs->gr, sizeof(regs->gr));
225	err |= __copy_to_user(sc->sc_fr, regs->fr, sizeof(regs->fr));
226	err |= __put_user(regs->sar, &sc->sc_sar);
227	DBG(1,"setup_sigcontext: r28 is %ld\n", regs->gr[28]);
228
229	return err;
230}
231
232static long
233setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
234	       sigset_t *set, struct pt_regs *regs, int in_syscall)
235{
236	struct rt_sigframe __user *frame;
237	unsigned long rp, usp;
238	unsigned long haddr, sigframe_size;
239	int err = 0;
240#ifdef CONFIG_64BIT
241	compat_int_t compat_val;
242	struct compat_rt_sigframe __user * compat_frame;
243	compat_sigset_t compat_set;
244#endif
245	
246	usp = (regs->gr[30] & ~(0x01UL));
247	/*FIXME: frame_size parameter is unused, remove it. */
248	frame = get_sigframe(ka, usp, sizeof(*frame));
249
250	DBG(1,"SETUP_RT_FRAME: START\n");
251	DBG(1,"setup_rt_frame: frame %p info %p\n", frame, info);
252
253	
254#ifdef CONFIG_64BIT
255
256	compat_frame = (struct compat_rt_sigframe __user *)frame;
257	
258	if (is_compat_task()) {
259		DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &compat_frame->info);
260		err |= copy_siginfo_to_user32(&compat_frame->info, info);
261		DBG(1,"SETUP_RT_FRAME: 1\n");
262		compat_val = (compat_int_t)current->sas_ss_sp;
263		err |= __put_user(compat_val, &compat_frame->uc.uc_stack.ss_sp);
264		DBG(1,"SETUP_RT_FRAME: 2\n");
265		compat_val = (compat_int_t)current->sas_ss_size;
266		err |= __put_user(compat_val, &compat_frame->uc.uc_stack.ss_size);
267		DBG(1,"SETUP_RT_FRAME: 3\n");
268		compat_val = sas_ss_flags(regs->gr[30]);		
269		err |= __put_user(compat_val, &compat_frame->uc.uc_stack.ss_flags);		
270		DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &compat_frame->uc);
271		DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &compat_frame->uc.uc_mcontext);
272		err |= setup_sigcontext32(&compat_frame->uc.uc_mcontext, 
273					&compat_frame->regs, regs, in_syscall);
274		sigset_64to32(&compat_set,set);
275		err |= __copy_to_user(&compat_frame->uc.uc_sigmask, &compat_set, sizeof(compat_set));
276	} else
277#endif
278	{	
279		DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &frame->info);
280		err |= copy_siginfo_to_user(&frame->info, info);
281		err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
282		err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
283		err |= __put_user(sas_ss_flags(regs->gr[30]),
284				  &frame->uc.uc_stack.ss_flags);
285		DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &frame->uc);
286		DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &frame->uc.uc_mcontext);
287		err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, in_syscall);
288		/* FIXME: Should probably be converted as well for the compat case */
289		err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
290	}
291	
292	if (err)
293		goto give_sigsegv;
294
295	/* Set up to return from userspace.  If provided, use a stub
296	   already in userspace. The first words of tramp are used to
297	   save the previous sigrestartblock trampoline that might be
298	   on the stack. We start the sigreturn trampoline at 
299	   SIGRESTARTBLOCK_TRAMP+X. */
300	err |= __put_user(in_syscall ? INSN_LDI_R25_1 : INSN_LDI_R25_0,
301			&frame->tramp[SIGRESTARTBLOCK_TRAMP+0]);
302	err |= __put_user(INSN_LDI_R20, 
303			&frame->tramp[SIGRESTARTBLOCK_TRAMP+1]);
304	err |= __put_user(INSN_BLE_SR2_R0, 
305			&frame->tramp[SIGRESTARTBLOCK_TRAMP+2]);
306	err |= __put_user(INSN_NOP, &frame->tramp[SIGRESTARTBLOCK_TRAMP+3]);
307
308#if DEBUG_SIG
309	/* Assert that we're flushing in the correct space... */
310	{
311		int sid;
312		asm ("mfsp %%sr3,%0" : "=r" (sid));
313		DBG(1,"setup_rt_frame: Flushing 64 bytes at space %#x offset %p\n",
314		       sid, frame->tramp);
315	}
316#endif
317
318	flush_user_dcache_range((unsigned long) &frame->tramp[0],
319			   (unsigned long) &frame->tramp[TRAMP_SIZE]);
320	flush_user_icache_range((unsigned long) &frame->tramp[0],
321			   (unsigned long) &frame->tramp[TRAMP_SIZE]);
322
323	/* TRAMP Words 0-4, Length 5 = SIGRESTARTBLOCK_TRAMP
324	 * TRAMP Words 5-9, Length 4 = SIGRETURN_TRAMP
325	 * So the SIGRETURN_TRAMP is at the end of SIGRESTARTBLOCK_TRAMP
326	 */
327	rp = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP];
328
329	if (err)
330		goto give_sigsegv;
331
332	haddr = A(ka->sa.sa_handler);
333	/* The sa_handler may be a pointer to a function descriptor */
334#ifdef CONFIG_64BIT
335	if (is_compat_task()) {
336#endif
337		if (haddr & PA_PLABEL_FDESC) {
338			Elf32_Fdesc fdesc;
339			Elf32_Fdesc __user *ufdesc = (Elf32_Fdesc __user *)A(haddr & ~3);
340
341			err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
342
343			if (err)
344				goto give_sigsegv;
345
346			haddr = fdesc.addr;
347			regs->gr[19] = fdesc.gp;
348		}
349#ifdef CONFIG_64BIT
350	} else {
351		Elf64_Fdesc fdesc;
352		Elf64_Fdesc __user *ufdesc = (Elf64_Fdesc __user *)A(haddr & ~3);
353		
354		err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
355		
356		if (err)
357			goto give_sigsegv;
358		
359		haddr = fdesc.addr;
360		regs->gr[19] = fdesc.gp;
361		DBG(1,"setup_rt_frame: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n",
362		     haddr, regs->gr[19], in_syscall);
363	}
364#endif
365
366	/* The syscall return path will create IAOQ values from r31.
367	 */
368	sigframe_size = PARISC_RT_SIGFRAME_SIZE;
369#ifdef CONFIG_64BIT
370	if (is_compat_task())
371		sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
372#endif
373	if (in_syscall) {
374		regs->gr[31] = haddr;
375#ifdef CONFIG_64BIT
376		if (!test_thread_flag(TIF_32BIT))
377			sigframe_size |= 1;
378#endif
379	} else {
380		unsigned long psw = USER_PSW;
381#ifdef CONFIG_64BIT
382		if (!test_thread_flag(TIF_32BIT))
383			psw |= PSW_W;
384#endif
385
386		/* If we are singlestepping, arrange a trap to be delivered
387		   when we return to userspace. Note the semantics -- we
388		   should trap before the first insn in the handler is
389		   executed. Ref:
390			http://sources.redhat.com/ml/gdb/2004-11/msg00245.html
391		 */
392		if (pa_psw(current)->r) {
393			pa_psw(current)->r = 0;
394			psw |= PSW_R;
395			mtctl(-1, 0);
396		}
397
398		regs->gr[0] = psw;
399		regs->iaoq[0] = haddr | 3;
400		regs->iaoq[1] = regs->iaoq[0] + 4;
401	}
402
403	regs->gr[2]  = rp;                /* userland return pointer */
404	regs->gr[26] = sig;               /* signal number */
405	
406#ifdef CONFIG_64BIT
407	if (is_compat_task()) {
408		regs->gr[25] = A(&compat_frame->info); /* siginfo pointer */
409		regs->gr[24] = A(&compat_frame->uc);   /* ucontext pointer */
410	} else
411#endif
412	{		
413		regs->gr[25] = A(&frame->info); /* siginfo pointer */
414		regs->gr[24] = A(&frame->uc);   /* ucontext pointer */
415	}
416	
417	DBG(1,"setup_rt_frame: making sigreturn frame: %#lx + %#lx = %#lx\n",
418	       regs->gr[30], sigframe_size,
419	       regs->gr[30] + sigframe_size);
420	/* Raise the user stack pointer to make a proper call frame. */
421	regs->gr[30] = (A(frame) + sigframe_size);
422
423
424	DBG(1,"setup_rt_frame: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n",
425	       current->comm, current->pid, frame, regs->gr[30],
426	       regs->iaoq[0], regs->iaoq[1], rp);
427
428	return 1;
429
430give_sigsegv:
431	DBG(1,"setup_rt_frame: sending SIGSEGV\n");
432	force_sigsegv(sig, current);
433	return 0;
434}
435
436/*
437 * OK, we're invoking a handler.
438 */	
439
440static long
441handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
442		struct pt_regs *regs, int in_syscall)
443{
 
444	sigset_t *oldset = sigmask_to_save();
 
445	DBG(1,"handle_signal: sig=%ld, ka=%p, info=%p, oldset=%p, regs=%p\n",
446	       sig, ka, info, oldset, regs);
447	
448	/* Set up the stack frame */
449	if (!setup_rt_frame(sig, ka, info, oldset, regs, in_syscall))
450		return 0;
451
452	signal_delivered(sig, info, ka, regs, 
453		test_thread_flag(TIF_SINGLESTEP) ||
454		test_thread_flag(TIF_BLOCKSTEP));
455
456	DBG(1,KERN_DEBUG "do_signal: Exit (success), regs->gr[28] = %ld\n",
457		regs->gr[28]);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
458
459	return 1;
 
 
 
 
 
 
 
 
 
 
 
 
460}
461
462static inline void
463syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
464{
 
 
 
465	/* Check the return code */
466	switch (regs->gr[28]) {
467	case -ERESTART_RESTARTBLOCK:
468	case -ERESTARTNOHAND:
469		DBG(1,"ERESTARTNOHAND: returning -EINTR\n");
470		regs->gr[28] = -EINTR;
471		break;
472
473	case -ERESTARTSYS:
474		if (!(ka->sa.sa_flags & SA_RESTART)) {
475			DBG(1,"ERESTARTSYS: putting -EINTR\n");
476			regs->gr[28] = -EINTR;
477			break;
478		}
479		/* fallthrough */
480	case -ERESTARTNOINTR:
481		/* A syscall is just a branch, so all
482		 * we have to do is fiddle the return pointer.
483		 */
484		regs->gr[31] -= 8; /* delayed branching */
485		/* Preserve original r28. */
486		regs->gr[28] = regs->orig_r28;
487		break;
488	}
489}
490
491static inline void
492insert_restart_trampoline(struct pt_regs *regs)
493{
 
 
 
494	switch(regs->gr[28]) {
495	case -ERESTART_RESTARTBLOCK: {
496		/* Restart the system call - no handlers present */
497		unsigned int *usp = (unsigned int *)regs->gr[30];
 
 
 
498
499		/* Setup a trampoline to restart the syscall
500		 * with __NR_restart_syscall
501		 *
502		 *  0: <return address (orig r31)>
503		 *  4: <2nd half for 64-bit>
504		 *  8: ldw 0(%sp), %r31
505		 * 12: be 0x100(%sr2, %r0)
506		 * 16: ldi __NR_restart_syscall, %r20
507		 */
508#ifdef CONFIG_64BIT
509		put_user(regs->gr[31] >> 32, &usp[0]);
510		put_user(regs->gr[31] & 0xffffffff, &usp[1]);
511		put_user(0x0fc010df, &usp[2]);
512#else
513		put_user(regs->gr[31], &usp[0]);
514		put_user(0x0fc0109f, &usp[2]);
515#endif
516		put_user(0xe0008200, &usp[3]);
517		put_user(0x34140000, &usp[4]);
518
519		/* Stack is 64-byte aligned, and we only need
520		 * to flush 1 cache line.
521		 * Flushing one cacheline is cheap.
522		 * "sync" on bigger (> 4 way) boxes is not.
523		 */
524		flush_user_dcache_range(regs->gr[30], regs->gr[30] + 4);
525		flush_user_icache_range(regs->gr[30], regs->gr[30] + 4);
526
527		regs->gr[31] = regs->gr[30] + 8;
528		/* Preserve original r28. */
529		regs->gr[28] = regs->orig_r28;
530
531		return;
532	}
533	case -ERESTARTNOHAND:
534	case -ERESTARTSYS:
535	case -ERESTARTNOINTR: {
536		/* Hooray for delayed branching.  We don't
537		 * have to restore %r20 (the system call
538		 * number) because it gets loaded in the delay
539		 * slot of the branch external instruction.
540		 */
541		regs->gr[31] -= 8;
542		/* Preserve original r28. */
543		regs->gr[28] = regs->orig_r28;
544
545		return;
546	}
547	default:
548		break;
549	}
550}
551
552/*
553 * Note that 'init' is a special process: it doesn't get signals it doesn't
554 * want to handle. Thus you cannot kill init even with a SIGKILL even by
555 * mistake.
556 *
557 * We need to be able to restore the syscall arguments (r21-r26) to
558 * restart syscalls.  Thus, the syscall path should save them in the
559 * pt_regs structure (it's okay to do so since they are caller-save
560 * registers).  As noted below, the syscall number gets restored for
561 * us due to the magic of delayed branching.
562 */
563asmlinkage void
564do_signal(struct pt_regs *regs, long in_syscall)
565{
566	siginfo_t info;
567	struct k_sigaction ka;
568	int signr;
569
570	DBG(1,"\ndo_signal: regs=0x%p, sr7 %#lx, in_syscall=%d\n",
571	       regs, regs->sr[7], in_syscall);
572
573	/* Everyone else checks to see if they are in kernel mode at
574	   this point and exits if that's the case.  I'm not sure why
575	   we would be called in that case, but for some reason we
576	   are. */
577
578	/* May need to force signal if handle_signal failed to deliver */
579	while (1) {
580		signr = get_signal_to_deliver(&info, &ka, regs, NULL);
581		DBG(3,"do_signal: signr = %d, regs->gr[28] = %ld\n", signr, regs->gr[28]); 
582	
583		if (signr <= 0)
584		  break;
585		
586		/* Restart a system call if necessary. */
587		if (in_syscall)
588			syscall_restart(regs, &ka);
589
590		/* Whee!  Actually deliver the signal.  If the
591		   delivery failed, we need to continue to iterate in
592		   this loop so we can deliver the SIGSEGV... */
593		if (handle_signal(signr, &info, &ka, regs, in_syscall))
594			return;
595	}
596	/* end of while(1) looping forever if we can't force a signal */
597
598	/* Did we come from a system call? */
599	if (in_syscall)
600		insert_restart_trampoline(regs);
601	
602	DBG(1,"do_signal: Exit (not delivered), regs->gr[28] = %ld\n", 
603		regs->gr[28]);
604
605	restore_saved_sigmask();
606}
607
608void do_notify_resume(struct pt_regs *regs, long in_syscall)
609{
610	if (test_thread_flag(TIF_SIGPENDING))
611		do_signal(regs, in_syscall);
612
613	if (test_thread_flag(TIF_NOTIFY_RESUME)) {
614		clear_thread_flag(TIF_NOTIFY_RESUME);
615		tracehook_notify_resume(regs);
616	}
617}