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1/*
2 * OpenRISC signal.c
3 *
4 * Linux architectural port borrowing liberally from similar works of
5 * others. All original copyrights apply as per the original source
6 * declaration.
7 *
8 * Modifications for the OpenRISC architecture:
9 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
10 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
16 */
17
18#include <linux/sched.h>
19#include <linux/mm.h>
20#include <linux/smp.h>
21#include <linux/kernel.h>
22#include <linux/signal.h>
23#include <linux/errno.h>
24#include <linux/wait.h>
25#include <linux/ptrace.h>
26#include <linux/unistd.h>
27#include <linux/stddef.h>
28#include <linux/tracehook.h>
29
30#include <asm/processor.h>
31#include <asm/syscall.h>
32#include <asm/ucontext.h>
33#include <linux/uaccess.h>
34
35#define DEBUG_SIG 0
36
37struct rt_sigframe {
38 struct siginfo info;
39 struct ucontext uc;
40 unsigned char retcode[16]; /* trampoline code */
41};
42
43static int restore_sigcontext(struct pt_regs *regs,
44 struct sigcontext __user *sc)
45{
46 int err = 0;
47
48 /* Always make any pending restarted system calls return -EINTR */
49 current->restart_block.fn = do_no_restart_syscall;
50
51 /*
52 * Restore the regs from &sc->regs.
53 * (sc is already checked for VERIFY_READ since the sigframe was
54 * checked in sys_sigreturn previously)
55 */
56 err |= __copy_from_user(regs, sc->regs.gpr, 32 * sizeof(unsigned long));
57 err |= __copy_from_user(®s->pc, &sc->regs.pc, sizeof(unsigned long));
58 err |= __copy_from_user(®s->sr, &sc->regs.sr, sizeof(unsigned long));
59
60 /* make sure the SM-bit is cleared so user-mode cannot fool us */
61 regs->sr &= ~SPR_SR_SM;
62
63 regs->orig_gpr11 = -1; /* Avoid syscall restart checks */
64
65 /* TODO: the other ports use regs->orig_XX to disable syscall checks
66 * after this completes, but we don't use that mechanism. maybe we can
67 * use it now ?
68 */
69
70 return err;
71}
72
73asmlinkage long _sys_rt_sigreturn(struct pt_regs *regs)
74{
75 struct rt_sigframe *frame = (struct rt_sigframe __user *)regs->sp;
76 sigset_t set;
77
78 /*
79 * Since we stacked the signal on a dword boundary,
80 * then frame should be dword aligned here. If it's
81 * not, then the user is trying to mess with us.
82 */
83 if (((long)frame) & 3)
84 goto badframe;
85
86 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
87 goto badframe;
88 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
89 goto badframe;
90
91 set_current_blocked(&set);
92
93 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
94 goto badframe;
95
96 if (restore_altstack(&frame->uc.uc_stack))
97 goto badframe;
98
99 return regs->gpr[11];
100
101badframe:
102 force_sig(SIGSEGV, current);
103 return 0;
104}
105
106/*
107 * Set up a signal frame.
108 */
109
110static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
111{
112 int err = 0;
113
114 /* copy the regs */
115 /* There should be no need to save callee-saved registers here...
116 * ...but we save them anyway. Revisit this
117 */
118 err |= __copy_to_user(sc->regs.gpr, regs, 32 * sizeof(unsigned long));
119 err |= __copy_to_user(&sc->regs.pc, ®s->pc, sizeof(unsigned long));
120 err |= __copy_to_user(&sc->regs.sr, ®s->sr, sizeof(unsigned long));
121
122 return err;
123}
124
125static inline unsigned long align_sigframe(unsigned long sp)
126{
127 return sp & ~3UL;
128}
129
130/*
131 * Work out where the signal frame should go. It's either on the user stack
132 * or the alternate stack.
133 */
134
135static inline void __user *get_sigframe(struct ksignal *ksig,
136 struct pt_regs *regs, size_t frame_size)
137{
138 unsigned long sp = regs->sp;
139
140 /* redzone */
141 sp -= STACK_FRAME_OVERHEAD;
142 sp = sigsp(sp, ksig);
143 sp = align_sigframe(sp - frame_size);
144
145 return (void __user *)sp;
146}
147
148/* grab and setup a signal frame.
149 *
150 * basically we stack a lot of state info, and arrange for the
151 * user-mode program to return to the kernel using either a
152 * trampoline which performs the syscall sigreturn, or a provided
153 * user-mode trampoline.
154 */
155static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
156 struct pt_regs *regs)
157{
158 struct rt_sigframe *frame;
159 unsigned long return_ip;
160 int err = 0;
161
162 frame = get_sigframe(ksig, regs, sizeof(*frame));
163
164 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
165 return -EFAULT;
166
167 /* Create siginfo. */
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->sp);
175 err |= setup_sigcontext(regs, &frame->uc.uc_mcontext);
176
177 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
178
179 if (err)
180 return -EFAULT;
181
182 /* trampoline - the desired return ip is the retcode itself */
183 return_ip = (unsigned long)&frame->retcode;
184 /* This is:
185 l.ori r11,r0,__NR_sigreturn
186 l.sys 1
187 */
188 err |= __put_user(0xa960, (short *)(frame->retcode + 0));
189 err |= __put_user(__NR_rt_sigreturn, (short *)(frame->retcode + 2));
190 err |= __put_user(0x20000001, (unsigned long *)(frame->retcode + 4));
191 err |= __put_user(0x15000000, (unsigned long *)(frame->retcode + 8));
192
193 if (err)
194 return -EFAULT;
195
196 /* Set up registers for signal handler */
197 regs->pc = (unsigned long)ksig->ka.sa.sa_handler; /* what we enter NOW */
198 regs->gpr[9] = (unsigned long)return_ip; /* what we enter LATER */
199 regs->gpr[3] = (unsigned long)ksig->sig; /* arg 1: signo */
200 regs->gpr[4] = (unsigned long)&frame->info; /* arg 2: (siginfo_t*) */
201 regs->gpr[5] = (unsigned long)&frame->uc; /* arg 3: ucontext */
202
203 /* actually move the usp to reflect the stacked frame */
204 regs->sp = (unsigned long)frame;
205
206 return 0;
207}
208
209static inline void
210handle_signal(struct ksignal *ksig, struct pt_regs *regs)
211{
212 int ret;
213
214 ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
215
216 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
217}
218
219/*
220 * Note that 'init' is a special process: it doesn't get signals it doesn't
221 * want to handle. Thus you cannot kill init even with a SIGKILL even by
222 * mistake.
223 *
224 * Also note that the regs structure given here as an argument, is the latest
225 * pushed pt_regs. It may or may not be the same as the first pushed registers
226 * when the initial usermode->kernelmode transition took place. Therefore
227 * we can use user_mode(regs) to see if we came directly from kernel or user
228 * mode below.
229 */
230
231int do_signal(struct pt_regs *regs, int syscall)
232{
233 struct ksignal ksig;
234 unsigned long continue_addr = 0;
235 unsigned long restart_addr = 0;
236 unsigned long retval = 0;
237 int restart = 0;
238
239 if (syscall) {
240 continue_addr = regs->pc;
241 restart_addr = continue_addr - 4;
242 retval = regs->gpr[11];
243
244 /*
245 * Setup syscall restart here so that a debugger will
246 * see the already changed PC.
247 */
248 switch (retval) {
249 case -ERESTART_RESTARTBLOCK:
250 restart = -2;
251 /* Fall through */
252 case -ERESTARTNOHAND:
253 case -ERESTARTSYS:
254 case -ERESTARTNOINTR:
255 restart++;
256 regs->gpr[11] = regs->orig_gpr11;
257 regs->pc = restart_addr;
258 break;
259 }
260 }
261
262 /*
263 * Get the signal to deliver. During the call to get_signal the
264 * debugger may change all our registers so we may need to revert
265 * the decision to restart the syscall; specifically, if the PC is
266 * changed, don't restart the syscall.
267 */
268 if (get_signal(&ksig)) {
269 if (unlikely(restart) && regs->pc == restart_addr) {
270 if (retval == -ERESTARTNOHAND ||
271 retval == -ERESTART_RESTARTBLOCK
272 || (retval == -ERESTARTSYS
273 && !(ksig.ka.sa.sa_flags & SA_RESTART))) {
274 /* No automatic restart */
275 regs->gpr[11] = -EINTR;
276 regs->pc = continue_addr;
277 }
278 }
279 handle_signal(&ksig, regs);
280 } else {
281 /* no handler */
282 restore_saved_sigmask();
283 /*
284 * Restore pt_regs PC as syscall restart will be handled by
285 * kernel without return to userspace
286 */
287 if (unlikely(restart) && regs->pc == restart_addr) {
288 regs->pc = continue_addr;
289 return restart;
290 }
291 }
292
293 return 0;
294}
295
296asmlinkage int
297do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
298{
299 do {
300 if (likely(thread_flags & _TIF_NEED_RESCHED)) {
301 schedule();
302 } else {
303 if (unlikely(!user_mode(regs)))
304 return 0;
305 local_irq_enable();
306 if (thread_flags & _TIF_SIGPENDING) {
307 int restart = do_signal(regs, syscall);
308 if (unlikely(restart)) {
309 /*
310 * Restart without handlers.
311 * Deal with it without leaving
312 * the kernel space.
313 */
314 return restart;
315 }
316 syscall = 0;
317 } else {
318 clear_thread_flag(TIF_NOTIFY_RESUME);
319 tracehook_notify_resume(regs);
320 }
321 }
322 local_irq_disable();
323 thread_flags = current_thread_info()->flags;
324 } while (thread_flags & _TIF_WORK_MASK);
325 return 0;
326}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * OpenRISC signal.c
4 *
5 * Linux architectural port borrowing liberally from similar works of
6 * others. All original copyrights apply as per the original source
7 * declaration.
8 *
9 * Modifications for the OpenRISC architecture:
10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
11 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
12 */
13
14#include <linux/sched.h>
15#include <linux/mm.h>
16#include <linux/smp.h>
17#include <linux/kernel.h>
18#include <linux/signal.h>
19#include <linux/errno.h>
20#include <linux/wait.h>
21#include <linux/ptrace.h>
22#include <linux/unistd.h>
23#include <linux/stddef.h>
24#include <linux/tracehook.h>
25
26#include <asm/processor.h>
27#include <asm/syscall.h>
28#include <asm/ucontext.h>
29#include <linux/uaccess.h>
30
31#define DEBUG_SIG 0
32
33struct rt_sigframe {
34 struct siginfo info;
35 struct ucontext uc;
36 unsigned char retcode[16]; /* trampoline code */
37};
38
39static int restore_sigcontext(struct pt_regs *regs,
40 struct sigcontext __user *sc)
41{
42 int err = 0;
43
44 /* Always make any pending restarted system calls return -EINTR */
45 current->restart_block.fn = do_no_restart_syscall;
46
47 /*
48 * Restore the regs from &sc->regs.
49 * (sc is already checked since the sigframe was
50 * checked in sys_sigreturn previously)
51 */
52 err |= __copy_from_user(regs, sc->regs.gpr, 32 * sizeof(unsigned long));
53 err |= __copy_from_user(®s->pc, &sc->regs.pc, sizeof(unsigned long));
54 err |= __copy_from_user(®s->sr, &sc->regs.sr, sizeof(unsigned long));
55
56 /* make sure the SM-bit is cleared so user-mode cannot fool us */
57 regs->sr &= ~SPR_SR_SM;
58
59 regs->orig_gpr11 = -1; /* Avoid syscall restart checks */
60
61 /* TODO: the other ports use regs->orig_XX to disable syscall checks
62 * after this completes, but we don't use that mechanism. maybe we can
63 * use it now ?
64 */
65
66 return err;
67}
68
69asmlinkage long _sys_rt_sigreturn(struct pt_regs *regs)
70{
71 struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->sp;
72 sigset_t set;
73
74 /*
75 * Since we stacked the signal on a dword boundary,
76 * then frame should be dword aligned here. If it's
77 * not, then the user is trying to mess with us.
78 */
79 if (((unsigned long)frame) & 3)
80 goto badframe;
81
82 if (!access_ok(frame, sizeof(*frame)))
83 goto badframe;
84 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
85 goto badframe;
86
87 set_current_blocked(&set);
88
89 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
90 goto badframe;
91
92 if (restore_altstack(&frame->uc.uc_stack))
93 goto badframe;
94
95 return regs->gpr[11];
96
97badframe:
98 force_sig(SIGSEGV);
99 return 0;
100}
101
102/*
103 * Set up a signal frame.
104 */
105
106static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
107{
108 int err = 0;
109
110 /* copy the regs */
111 /* There should be no need to save callee-saved registers here...
112 * ...but we save them anyway. Revisit this
113 */
114 err |= __copy_to_user(sc->regs.gpr, regs, 32 * sizeof(unsigned long));
115 err |= __copy_to_user(&sc->regs.pc, ®s->pc, sizeof(unsigned long));
116 err |= __copy_to_user(&sc->regs.sr, ®s->sr, sizeof(unsigned long));
117
118 return err;
119}
120
121static inline unsigned long align_sigframe(unsigned long sp)
122{
123 return sp & ~3UL;
124}
125
126/*
127 * Work out where the signal frame should go. It's either on the user stack
128 * or the alternate stack.
129 */
130
131static inline void __user *get_sigframe(struct ksignal *ksig,
132 struct pt_regs *regs, size_t frame_size)
133{
134 unsigned long sp = regs->sp;
135
136 /* redzone */
137 sp -= STACK_FRAME_OVERHEAD;
138 sp = sigsp(sp, ksig);
139 sp = align_sigframe(sp - frame_size);
140
141 return (void __user *)sp;
142}
143
144/* grab and setup a signal frame.
145 *
146 * basically we stack a lot of state info, and arrange for the
147 * user-mode program to return to the kernel using either a
148 * trampoline which performs the syscall sigreturn, or a provided
149 * user-mode trampoline.
150 */
151static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
152 struct pt_regs *regs)
153{
154 struct rt_sigframe __user *frame;
155 unsigned long return_ip;
156 int err = 0;
157
158 frame = get_sigframe(ksig, regs, sizeof(*frame));
159
160 if (!access_ok(frame, sizeof(*frame)))
161 return -EFAULT;
162
163 /* Create siginfo. */
164 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
165 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
166
167 /* Create the ucontext. */
168 err |= __put_user(0, &frame->uc.uc_flags);
169 err |= __put_user(NULL, &frame->uc.uc_link);
170 err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
171 err |= setup_sigcontext(regs, &frame->uc.uc_mcontext);
172
173 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
174
175 if (err)
176 return -EFAULT;
177
178 /* trampoline - the desired return ip is the retcode itself */
179 return_ip = (unsigned long)&frame->retcode;
180 /* This is:
181 l.ori r11,r0,__NR_sigreturn
182 l.sys 1
183 */
184 err |= __put_user(0xa960, (short __user *)(frame->retcode + 0));
185 err |= __put_user(__NR_rt_sigreturn, (short __user *)(frame->retcode + 2));
186 err |= __put_user(0x20000001, (unsigned long __user *)(frame->retcode + 4));
187 err |= __put_user(0x15000000, (unsigned long __user *)(frame->retcode + 8));
188
189 if (err)
190 return -EFAULT;
191
192 /* Set up registers for signal handler */
193 regs->pc = (unsigned long)ksig->ka.sa.sa_handler; /* what we enter NOW */
194 regs->gpr[9] = (unsigned long)return_ip; /* what we enter LATER */
195 regs->gpr[3] = (unsigned long)ksig->sig; /* arg 1: signo */
196 regs->gpr[4] = (unsigned long)&frame->info; /* arg 2: (siginfo_t*) */
197 regs->gpr[5] = (unsigned long)&frame->uc; /* arg 3: ucontext */
198
199 /* actually move the usp to reflect the stacked frame */
200 regs->sp = (unsigned long)frame;
201
202 return 0;
203}
204
205static inline void
206handle_signal(struct ksignal *ksig, struct pt_regs *regs)
207{
208 int ret;
209
210 ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
211
212 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
213}
214
215/*
216 * Note that 'init' is a special process: it doesn't get signals it doesn't
217 * want to handle. Thus you cannot kill init even with a SIGKILL even by
218 * mistake.
219 *
220 * Also note that the regs structure given here as an argument, is the latest
221 * pushed pt_regs. It may or may not be the same as the first pushed registers
222 * when the initial usermode->kernelmode transition took place. Therefore
223 * we can use user_mode(regs) to see if we came directly from kernel or user
224 * mode below.
225 */
226
227int do_signal(struct pt_regs *regs, int syscall)
228{
229 struct ksignal ksig;
230 unsigned long continue_addr = 0;
231 unsigned long restart_addr = 0;
232 unsigned long retval = 0;
233 int restart = 0;
234
235 if (syscall) {
236 continue_addr = regs->pc;
237 restart_addr = continue_addr - 4;
238 retval = regs->gpr[11];
239
240 /*
241 * Setup syscall restart here so that a debugger will
242 * see the already changed PC.
243 */
244 switch (retval) {
245 case -ERESTART_RESTARTBLOCK:
246 restart = -2;
247 fallthrough;
248 case -ERESTARTNOHAND:
249 case -ERESTARTSYS:
250 case -ERESTARTNOINTR:
251 restart++;
252 regs->gpr[11] = regs->orig_gpr11;
253 regs->pc = restart_addr;
254 break;
255 }
256 }
257
258 /*
259 * Get the signal to deliver. During the call to get_signal the
260 * debugger may change all our registers so we may need to revert
261 * the decision to restart the syscall; specifically, if the PC is
262 * changed, don't restart the syscall.
263 */
264 if (get_signal(&ksig)) {
265 if (unlikely(restart) && regs->pc == restart_addr) {
266 if (retval == -ERESTARTNOHAND ||
267 retval == -ERESTART_RESTARTBLOCK
268 || (retval == -ERESTARTSYS
269 && !(ksig.ka.sa.sa_flags & SA_RESTART))) {
270 /* No automatic restart */
271 regs->gpr[11] = -EINTR;
272 regs->pc = continue_addr;
273 }
274 }
275 handle_signal(&ksig, regs);
276 } else {
277 /* no handler */
278 restore_saved_sigmask();
279 /*
280 * Restore pt_regs PC as syscall restart will be handled by
281 * kernel without return to userspace
282 */
283 if (unlikely(restart) && regs->pc == restart_addr) {
284 regs->pc = continue_addr;
285 return restart;
286 }
287 }
288
289 return 0;
290}
291
292asmlinkage int
293do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
294{
295 do {
296 if (likely(thread_flags & _TIF_NEED_RESCHED)) {
297 schedule();
298 } else {
299 if (unlikely(!user_mode(regs)))
300 return 0;
301 local_irq_enable();
302 if (thread_flags & (_TIF_SIGPENDING|_TIF_NOTIFY_SIGNAL)) {
303 int restart = do_signal(regs, syscall);
304 if (unlikely(restart)) {
305 /*
306 * Restart without handlers.
307 * Deal with it without leaving
308 * the kernel space.
309 */
310 return restart;
311 }
312 syscall = 0;
313 } else {
314 tracehook_notify_resume(regs);
315 }
316 }
317 local_irq_disable();
318 thread_flags = current_thread_info()->flags;
319 } while (thread_flags & _TIF_WORK_MASK);
320 return 0;
321}