1/*
  2 * Signal handling
  3 *
  4 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
  5 * Copyright (C) 2008-2009 PetaLogix
  6 * Copyright (C) 2003,2004 John Williams <jwilliams@itee.uq.edu.au>
  7 * Copyright (C) 2001 NEC Corporation
  8 * Copyright (C) 2001 Miles Bader <miles@gnu.org>
  9 * Copyright (C) 1999,2000 Niibe Yutaka & Kaz Kojima
 10 * Copyright (C) 1991,1992 Linus Torvalds
 11 *
 12 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
 13 *
 14 * This file was was derived from the sh version, arch/sh/kernel/signal.c
 15 *
 16 * This file is subject to the terms and conditions of the GNU General
 17 * Public License. See the file COPYING in the main directory of this
 18 * archive for more details.
 19 */
 20
 21#include <linux/sched.h>
 22#include <linux/mm.h>
 23#include <linux/smp.h>
 24#include <linux/kernel.h>
 25#include <linux/signal.h>
 26#include <linux/errno.h>
 27#include <linux/wait.h>
 28#include <linux/ptrace.h>
 29#include <linux/unistd.h>
 30#include <linux/stddef.h>
 31#include <linux/personality.h>
 32#include <linux/percpu.h>
 33#include <linux/linkage.h>
 34#include <linux/tracehook.h>
 35#include <asm/entry.h>
 36#include <asm/ucontext.h>
 37#include <linux/uaccess.h>
 38#include <linux/syscalls.h>
 39#include <asm/cacheflush.h>
 40#include <asm/syscalls.h>
 41
 42/*
 43 * Do a signal return; undo the signal stack.
 44 */
 45struct sigframe {
 46	struct sigcontext sc;
 47	unsigned long extramask[_NSIG_WORDS-1];
 48	unsigned long tramp[2];	/* signal trampoline */
 49};
 50
 51struct rt_sigframe {
 52	struct siginfo info;
 53	struct ucontext uc;
 54	unsigned long tramp[2];	/* signal trampoline */
 55};
 56
 57static int restore_sigcontext(struct pt_regs *regs,
 58				struct sigcontext __user *sc, int *rval_p)
 59{
 60	unsigned int err = 0;
 61
 62#define COPY(x)		{err |= __get_user(regs->x, &sc->regs.x); }
 63	COPY(r0);
 64	COPY(r1);
 65	COPY(r2);	COPY(r3);	COPY(r4);	COPY(r5);
 66	COPY(r6);	COPY(r7);	COPY(r8);	COPY(r9);
 67	COPY(r10);	COPY(r11);	COPY(r12);	COPY(r13);
 68	COPY(r14);	COPY(r15);	COPY(r16);	COPY(r17);
 69	COPY(r18);	COPY(r19);	COPY(r20);	COPY(r21);
 70	COPY(r22);	COPY(r23);	COPY(r24);	COPY(r25);
 71	COPY(r26);	COPY(r27);	COPY(r28);	COPY(r29);
 72	COPY(r30);	COPY(r31);
 73	COPY(pc);	COPY(ear);	COPY(esr);	COPY(fsr);
 74#undef COPY
 75
 76	*rval_p = regs->r3;
 77
 78	return err;
 79}
 80
 81asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
 82{
 83	struct rt_sigframe __user *frame =
 84		(struct rt_sigframe __user *)(regs->r1);
 85
 86	sigset_t set;
 87	int rval;
 88
 89	/* Always make any pending restarted system calls return -EINTR */
 90	current->restart_block.fn = do_no_restart_syscall;
 91
 92	if (!access_ok(frame, sizeof(*frame)))
 93		goto badframe;
 94
 95	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 96		goto badframe;
 97
 98	set_current_blocked(&set);
 99
100	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &rval))
101		goto badframe;
102
103	if (restore_altstack(&frame->uc.uc_stack))
104		goto badframe;
105
106	return rval;
107
108badframe:
109	force_sig(SIGSEGV);
110	return 0;
111}
112
113/*
114 * Set up a signal frame.
115 */
116
117static int
118setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
119		unsigned long mask)
120{
121	int err = 0;
122
123#define COPY(x)		{err |= __put_user(regs->x, &sc->regs.x); }
124	COPY(r0);
125	COPY(r1);
126	COPY(r2);	COPY(r3);	COPY(r4);	COPY(r5);
127	COPY(r6);	COPY(r7);	COPY(r8);	COPY(r9);
128	COPY(r10);	COPY(r11);	COPY(r12);	COPY(r13);
129	COPY(r14);	COPY(r15);	COPY(r16);	COPY(r17);
130	COPY(r18);	COPY(r19);	COPY(r20);	COPY(r21);
131	COPY(r22);	COPY(r23);	COPY(r24);	COPY(r25);
132	COPY(r26);	COPY(r27);	COPY(r28);	COPY(r29);
133	COPY(r30);	COPY(r31);
134	COPY(pc);	COPY(ear);	COPY(esr);	COPY(fsr);
135#undef COPY
136
137	err |= __put_user(mask, &sc->oldmask);
138
139	return err;
140}
141
142/*
143 * Determine which stack to use..
144 */
145static inline void __user *
146get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size)
147{
148	/* Default to using normal stack */
149	unsigned long sp = sigsp(regs->r1, ksig);
150
151	return (void __user *)((sp - frame_size) & -8UL);
152}
153
154static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
155			  struct pt_regs *regs)
156{
157	struct rt_sigframe __user *frame;
158	int err = 0, sig = ksig->sig;
159	unsigned long address = 0;
160	pmd_t *pmdp;
161	pte_t *ptep;
162
163	frame = get_sigframe(ksig, regs, sizeof(*frame));
164
165	if (!access_ok(frame, sizeof(*frame)))
166		return -EFAULT;
167
168	if (ksig->ka.sa.sa_flags & SA_SIGINFO)
169		err |= copy_siginfo_to_user(&frame->info, &ksig->info);
170
171	/* Create the ucontext. */
172	err |= __put_user(0, &frame->uc.uc_flags);
173	err |= __put_user(NULL, &frame->uc.uc_link);
174	err |= __save_altstack(&frame->uc.uc_stack, regs->r1);
175	err |= setup_sigcontext(&frame->uc.uc_mcontext,
176			regs, set->sig[0]);
177	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
178
179	/* Set up to return from userspace. If provided, use a stub
180	 already in userspace. */
181	/* minus 8 is offset to cater for "rtsd r15,8" */
182	/* addi r12, r0, __NR_sigreturn */
183	err |= __put_user(0x31800000 | __NR_rt_sigreturn ,
184			frame->tramp + 0);
185	/* brki r14, 0x8 */
186	err |= __put_user(0xb9cc0008, frame->tramp + 1);
187
188	/* Return from sighandler will jump to the tramp.
189	 Negative 8 offset because return is rtsd r15, 8 */
190	regs->r15 = ((unsigned long)frame->tramp)-8;
191
192	address = ((unsigned long)frame->tramp);
193	pmdp = pmd_off(current->mm, address);
194
195	preempt_disable();
196	ptep = pte_offset_map(pmdp, address);
197	if (pte_present(*ptep)) {
198		address = (unsigned long) page_address(pte_page(*ptep));
199		/* MS: I need add offset in page */
200		address += ((unsigned long)frame->tramp) & ~PAGE_MASK;
201		/* MS address is virtual */
202		address = __virt_to_phys(address);
203		invalidate_icache_range(address, address + 8);
204		flush_dcache_range(address, address + 8);
205	}
206	pte_unmap(ptep);
 
207	preempt_enable();
208	if (err)
209		return -EFAULT;
210
211	/* Set up registers for signal handler */
212	regs->r1 = (unsigned long) frame;
213
214	/* Signal handler args: */
215	regs->r5 = sig; /* arg 0: signum */
216	regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */
217	regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */
218	/* Offset to handle microblaze rtid r14, 0 */
219	regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
220
221#ifdef DEBUG_SIG
222	pr_info("SIG deliver (%s:%d): sp=%p pc=%08lx\n",
223		current->comm, current->pid, frame, regs->pc);
224#endif
225
226	return 0;
227}
228
229/* Handle restarting system calls */
230static inline void
231handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
232{
233	switch (regs->r3) {
234	case -ERESTART_RESTARTBLOCK:
235	case -ERESTARTNOHAND:
236		if (!has_handler)
237			goto do_restart;
238		regs->r3 = -EINTR;
239		break;
240	case -ERESTARTSYS:
241		if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
242			regs->r3 = -EINTR;
243			break;
244	}
245		fallthrough;
246	case -ERESTARTNOINTR:
247do_restart:
248		/* offset of 4 bytes to re-execute trap (brki) instruction */
249		regs->pc -= 4;
250		break;
251	}
252}
253
254/*
255 * OK, we're invoking a handler
256 */
257
258static void
259handle_signal(struct ksignal *ksig, struct pt_regs *regs)
260{
261	sigset_t *oldset = sigmask_to_save();
262	int ret;
263
264	/* Set up the stack frame */
265	ret = setup_rt_frame(ksig, oldset, regs);
266
267	signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
268}
269
270/*
271 * Note that 'init' is a special process: it doesn't get signals it doesn't
272 * want to handle. Thus you cannot kill init even with a SIGKILL even by
273 * mistake.
274 *
275 * Note that we go through the signals twice: once to check the signals that
276 * the kernel can handle, and then we build all the user-level signal handling
277 * stack-frames in one go after that.
278 */
279static void do_signal(struct pt_regs *regs, int in_syscall)
280{
281	struct ksignal ksig;
282
283#ifdef DEBUG_SIG
284	pr_info("do signal: %p %d\n", regs, in_syscall);
285	pr_info("do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1,
286			regs->r12, current_thread_info()->flags);
287#endif
288
289	if (get_signal(&ksig)) {
290		/* Whee! Actually deliver the signal. */
291		if (in_syscall)
292			handle_restart(regs, &ksig.ka, 1);
293		handle_signal(&ksig, regs);
294		return;
295	}
296
297	if (in_syscall)
298		handle_restart(regs, NULL, 0);
299
300	/*
301	 * If there's no signal to deliver, we just put the saved sigmask
302	 * back.
303	 */
304	restore_saved_sigmask();
305}
306
307asmlinkage void do_notify_resume(struct pt_regs *regs, int in_syscall)
308{
309	if (test_thread_flag(TIF_SIGPENDING) ||
310	    test_thread_flag(TIF_NOTIFY_SIGNAL))
311		do_signal(regs, in_syscall);
312
313	if (test_thread_flag(TIF_NOTIFY_RESUME))
314		tracehook_notify_resume(regs);
315}

  1/*
  2 * Signal handling
  3 *
  4 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
  5 * Copyright (C) 2008-2009 PetaLogix
  6 * Copyright (C) 2003,2004 John Williams <jwilliams@itee.uq.edu.au>
  7 * Copyright (C) 2001 NEC Corporation
  8 * Copyright (C) 2001 Miles Bader <miles@gnu.org>
  9 * Copyright (C) 1999,2000 Niibe Yutaka & Kaz Kojima
 10 * Copyright (C) 1991,1992 Linus Torvalds
 11 *
 12 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
 13 *
 14 * This file was derived from the sh version, arch/sh/kernel/signal.c
 15 *
 16 * This file is subject to the terms and conditions of the GNU General
 17 * Public License. See the file COPYING in the main directory of this
 18 * archive for more details.
 19 */
 20
 21#include <linux/sched.h>
 22#include <linux/mm.h>
 23#include <linux/smp.h>
 24#include <linux/kernel.h>
 25#include <linux/signal.h>
 26#include <linux/errno.h>
 27#include <linux/wait.h>
 28#include <linux/ptrace.h>
 29#include <linux/unistd.h>
 30#include <linux/stddef.h>
 31#include <linux/personality.h>
 32#include <linux/percpu.h>
 33#include <linux/linkage.h>
 34#include <linux/resume_user_mode.h>
 35#include <asm/entry.h>
 36#include <asm/ucontext.h>
 37#include <linux/uaccess.h>
 38#include <linux/syscalls.h>
 39#include <asm/cacheflush.h>
 40#include <asm/syscalls.h>
 41
 42/*
 43 * Do a signal return; undo the signal stack.
 44 */
 45struct sigframe {
 46	struct sigcontext sc;
 47	unsigned long extramask[_NSIG_WORDS-1];
 48	unsigned long tramp[2];	/* signal trampoline */
 49};
 50
 51struct rt_sigframe {
 52	struct siginfo info;
 53	struct ucontext uc;
 54	unsigned long tramp[2];	/* signal trampoline */
 55};
 56
 57static int restore_sigcontext(struct pt_regs *regs,
 58				struct sigcontext __user *sc, int *rval_p)
 59{
 60	unsigned int err = 0;
 61
 62#define COPY(x)		{err |= __get_user(regs->x, &sc->regs.x); }
 63	COPY(r0);
 64	COPY(r1);
 65	COPY(r2);	COPY(r3);	COPY(r4);	COPY(r5);
 66	COPY(r6);	COPY(r7);	COPY(r8);	COPY(r9);
 67	COPY(r10);	COPY(r11);	COPY(r12);	COPY(r13);
 68	COPY(r14);	COPY(r15);	COPY(r16);	COPY(r17);
 69	COPY(r18);	COPY(r19);	COPY(r20);	COPY(r21);
 70	COPY(r22);	COPY(r23);	COPY(r24);	COPY(r25);
 71	COPY(r26);	COPY(r27);	COPY(r28);	COPY(r29);
 72	COPY(r30);	COPY(r31);
 73	COPY(pc);	COPY(ear);	COPY(esr);	COPY(fsr);
 74#undef COPY
 75
 76	*rval_p = regs->r3;
 77
 78	return err;
 79}
 80
 81asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
 82{
 83	struct rt_sigframe __user *frame =
 84		(struct rt_sigframe __user *)(regs->r1);
 85
 86	sigset_t set;
 87	int rval;
 88
 89	/* Always make any pending restarted system calls return -EINTR */
 90	current->restart_block.fn = do_no_restart_syscall;
 91
 92	if (!access_ok(frame, sizeof(*frame)))
 93		goto badframe;
 94
 95	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 96		goto badframe;
 97
 98	set_current_blocked(&set);
 99
100	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &rval))
101		goto badframe;
102
103	if (restore_altstack(&frame->uc.uc_stack))
104		goto badframe;
105
106	return rval;
107
108badframe:
109	force_sig(SIGSEGV);
110	return 0;
111}
112
113/*
114 * Set up a signal frame.
115 */
116
117static int
118setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
119		unsigned long mask)
120{
121	int err = 0;
122
123#define COPY(x)		{err |= __put_user(regs->x, &sc->regs.x); }
124	COPY(r0);
125	COPY(r1);
126	COPY(r2);	COPY(r3);	COPY(r4);	COPY(r5);
127	COPY(r6);	COPY(r7);	COPY(r8);	COPY(r9);
128	COPY(r10);	COPY(r11);	COPY(r12);	COPY(r13);
129	COPY(r14);	COPY(r15);	COPY(r16);	COPY(r17);
130	COPY(r18);	COPY(r19);	COPY(r20);	COPY(r21);
131	COPY(r22);	COPY(r23);	COPY(r24);	COPY(r25);
132	COPY(r26);	COPY(r27);	COPY(r28);	COPY(r29);
133	COPY(r30);	COPY(r31);
134	COPY(pc);	COPY(ear);	COPY(esr);	COPY(fsr);
135#undef COPY
136
137	err |= __put_user(mask, &sc->oldmask);
138
139	return err;
140}
141
142/*
143 * Determine which stack to use..
144 */
145static inline void __user *
146get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size)
147{
148	/* Default to using normal stack */
149	unsigned long sp = sigsp(regs->r1, ksig);
150
151	return (void __user *)((sp - frame_size) & -8UL);
152}
153
154static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
155			  struct pt_regs *regs)
156{
157	struct rt_sigframe __user *frame;
158	int err = 0, sig = ksig->sig;
159	unsigned long address = 0;
160	pmd_t *pmdp;
161	pte_t *ptep;
162
163	frame = get_sigframe(ksig, regs, sizeof(*frame));
164
165	if (!access_ok(frame, sizeof(*frame)))
166		return -EFAULT;
167
168	if (ksig->ka.sa.sa_flags & SA_SIGINFO)
169		err |= copy_siginfo_to_user(&frame->info, &ksig->info);
170
171	/* Create the ucontext. */
172	err |= __put_user(0, &frame->uc.uc_flags);
173	err |= __put_user(NULL, &frame->uc.uc_link);
174	err |= __save_altstack(&frame->uc.uc_stack, regs->r1);
175	err |= setup_sigcontext(&frame->uc.uc_mcontext,
176			regs, set->sig[0]);
177	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
178
179	/* Set up to return from userspace. If provided, use a stub
180	 already in userspace. */
181	/* minus 8 is offset to cater for "rtsd r15,8" */
182	/* addi r12, r0, __NR_sigreturn */
183	err |= __put_user(0x31800000 | __NR_rt_sigreturn ,
184			frame->tramp + 0);
185	/* brki r14, 0x8 */
186	err |= __put_user(0xb9cc0008, frame->tramp + 1);
187
188	/* Return from sighandler will jump to the tramp.
189	 Negative 8 offset because return is rtsd r15, 8 */
190	regs->r15 = ((unsigned long)frame->tramp)-8;
191
192	address = ((unsigned long)frame->tramp);
193	pmdp = pmd_off(current->mm, address);
194
195	preempt_disable();
196	ptep = pte_offset_map(pmdp, address);
197	if (ptep && pte_present(*ptep)) {
198		address = (unsigned long) page_address(pte_page(*ptep));
199		/* MS: I need add offset in page */
200		address += ((unsigned long)frame->tramp) & ~PAGE_MASK;
201		/* MS address is virtual */
202		address = __virt_to_phys(address);
203		invalidate_icache_range(address, address + 8);
204		flush_dcache_range(address, address + 8);
205	}
206	if (ptep)
207		pte_unmap(ptep);
208	preempt_enable();
209	if (err)
210		return -EFAULT;
211
212	/* Set up registers for signal handler */
213	regs->r1 = (unsigned long) frame;
214
215	/* Signal handler args: */
216	regs->r5 = sig; /* arg 0: signum */
217	regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */
218	regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */
219	/* Offset to handle microblaze rtid r14, 0 */
220	regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
221
222#ifdef DEBUG_SIG
223	pr_info("SIG deliver (%s:%d): sp=%p pc=%08lx\n",
224		current->comm, current->pid, frame, regs->pc);
225#endif
226
227	return 0;
228}
229
230/* Handle restarting system calls */
231static inline void
232handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
233{
234	switch (regs->r3) {
235	case -ERESTART_RESTARTBLOCK:
236	case -ERESTARTNOHAND:
237		if (!has_handler)
238			goto do_restart;
239		regs->r3 = -EINTR;
240		break;
241	case -ERESTARTSYS:
242		if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
243			regs->r3 = -EINTR;
244			break;
245	}
246		fallthrough;
247	case -ERESTARTNOINTR:
248do_restart:
249		/* offset of 4 bytes to re-execute trap (brki) instruction */
250		regs->pc -= 4;
251		break;
252	}
253}
254
255/*
256 * OK, we're invoking a handler
257 */
258
259static void
260handle_signal(struct ksignal *ksig, struct pt_regs *regs)
261{
262	sigset_t *oldset = sigmask_to_save();
263	int ret;
264
265	/* Set up the stack frame */
266	ret = setup_rt_frame(ksig, oldset, regs);
267
268	signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
269}
270
271/*
272 * Note that 'init' is a special process: it doesn't get signals it doesn't
273 * want to handle. Thus you cannot kill init even with a SIGKILL even by
274 * mistake.
275 *
276 * Note that we go through the signals twice: once to check the signals that
277 * the kernel can handle, and then we build all the user-level signal handling
278 * stack-frames in one go after that.
279 */
280static void do_signal(struct pt_regs *regs, int in_syscall)
281{
282	struct ksignal ksig;
283
284#ifdef DEBUG_SIG
285	pr_info("do signal: %p %d\n", regs, in_syscall);
286	pr_info("do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1,
287			regs->r12, read_thread_flags());
288#endif
289
290	if (get_signal(&ksig)) {
291		/* Whee! Actually deliver the signal. */
292		if (in_syscall)
293			handle_restart(regs, &ksig.ka, 1);
294		handle_signal(&ksig, regs);
295		return;
296	}
297
298	if (in_syscall)
299		handle_restart(regs, NULL, 0);
300
301	/*
302	 * If there's no signal to deliver, we just put the saved sigmask
303	 * back.
304	 */
305	restore_saved_sigmask();
306}
307
308asmlinkage void do_notify_resume(struct pt_regs *regs, int in_syscall)
309{
310	if (test_thread_flag(TIF_SIGPENDING) ||
311	    test_thread_flag(TIF_NOTIFY_SIGNAL))
312		do_signal(regs, in_syscall);
313
314	if (test_thread_flag(TIF_NOTIFY_RESUME))
315		resume_user_mode_work(regs);
316}