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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/resume_user_mode.h>
25
26#include <asm/processor.h>
27#include <asm/syscall.h>
28#include <asm/ucontext.h>
29#include <linux/uaccess.h>
30
31struct rt_sigframe {
32 struct siginfo info;
33 struct ucontext uc;
34 unsigned char retcode[16]; /* trampoline code */
35};
36
37asmlinkage long _sys_rt_sigreturn(struct pt_regs *regs);
38
39asmlinkage int do_work_pending(struct pt_regs *regs, unsigned int thread_flags,
40 int syscall);
41
42static int restore_sigcontext(struct pt_regs *regs,
43 struct sigcontext __user *sc)
44{
45 int err = 0;
46
47 /* Always make any pending restarted system calls return -EINTR */
48 current->restart_block.fn = do_no_restart_syscall;
49
50 /*
51 * Restore the regs from &sc->regs.
52 * (sc is already checked since the sigframe was
53 * checked in sys_sigreturn previously)
54 */
55 err |= __copy_from_user(regs, sc->regs.gpr, 32 * sizeof(unsigned long));
56 err |= __copy_from_user(®s->pc, &sc->regs.pc, sizeof(unsigned long));
57 err |= __copy_from_user(®s->sr, &sc->regs.sr, sizeof(unsigned long));
58 err |= __copy_from_user(®s->fpcsr, &sc->fpcsr, 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 __user *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 (((unsigned long)frame) & 3)
84 goto badframe;
85
86 if (!access_ok(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);
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 err |= __copy_to_user(&sc->fpcsr, ®s->fpcsr, sizeof(unsigned long));
122
123 return err;
124}
125
126static inline unsigned long align_sigframe(unsigned long sp)
127{
128 return sp & ~3UL;
129}
130
131/*
132 * Work out where the signal frame should go. It's either on the user stack
133 * or the alternate stack.
134 */
135
136static inline void __user *get_sigframe(struct ksignal *ksig,
137 struct pt_regs *regs, size_t frame_size)
138{
139 unsigned long sp = regs->sp;
140
141 /* redzone */
142 sp -= STACK_FRAME_OVERHEAD;
143 sp = sigsp(sp, ksig);
144 sp = align_sigframe(sp - frame_size);
145
146 return (void __user *)sp;
147}
148
149/* grab and setup a signal frame.
150 *
151 * basically we stack a lot of state info, and arrange for the
152 * user-mode program to return to the kernel using either a
153 * trampoline which performs the syscall sigreturn, or a provided
154 * user-mode trampoline.
155 */
156static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
157 struct pt_regs *regs)
158{
159 struct rt_sigframe __user *frame;
160 unsigned long return_ip;
161 int err = 0;
162
163 frame = get_sigframe(ksig, regs, sizeof(*frame));
164
165 if (!access_ok(frame, sizeof(*frame)))
166 return -EFAULT;
167
168 /* Create siginfo. */
169 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
170 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
171
172 /* Create the ucontext. */
173 err |= __put_user(0, &frame->uc.uc_flags);
174 err |= __put_user(NULL, &frame->uc.uc_link);
175 err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
176 err |= setup_sigcontext(regs, &frame->uc.uc_mcontext);
177
178 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
179
180 if (err)
181 return -EFAULT;
182
183 /* trampoline - the desired return ip is the retcode itself */
184 return_ip = (unsigned long)&frame->retcode;
185 /* This is:
186 l.ori r11,r0,__NR_sigreturn
187 l.sys 1
188 */
189 err |= __put_user(0xa960, (short __user *)(frame->retcode + 0));
190 err |= __put_user(__NR_rt_sigreturn, (short __user *)(frame->retcode + 2));
191 err |= __put_user(0x20000001, (unsigned long __user *)(frame->retcode + 4));
192 err |= __put_user(0x15000000, (unsigned long __user *)(frame->retcode + 8));
193
194 if (err)
195 return -EFAULT;
196
197 /* Set up registers for signal handler */
198 regs->pc = (unsigned long)ksig->ka.sa.sa_handler; /* what we enter NOW */
199 regs->gpr[9] = (unsigned long)return_ip; /* what we enter LATER */
200 regs->gpr[3] = (unsigned long)ksig->sig; /* arg 1: signo */
201 regs->gpr[4] = (unsigned long)&frame->info; /* arg 2: (siginfo_t*) */
202 regs->gpr[5] = (unsigned long)&frame->uc; /* arg 3: ucontext */
203
204 /* actually move the usp to reflect the stacked frame */
205 regs->sp = (unsigned long)frame;
206
207 return 0;
208}
209
210static inline void
211handle_signal(struct ksignal *ksig, struct pt_regs *regs)
212{
213 int ret;
214
215 ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
216
217 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
218}
219
220/*
221 * Note that 'init' is a special process: it doesn't get signals it doesn't
222 * want to handle. Thus you cannot kill init even with a SIGKILL even by
223 * mistake.
224 *
225 * Also note that the regs structure given here as an argument, is the latest
226 * pushed pt_regs. It may or may not be the same as the first pushed registers
227 * when the initial usermode->kernelmode transition took place. Therefore
228 * we can use user_mode(regs) to see if we came directly from kernel or user
229 * mode below.
230 */
231
232static int do_signal(struct pt_regs *regs, int syscall)
233{
234 struct ksignal ksig;
235 unsigned long continue_addr = 0;
236 unsigned long restart_addr = 0;
237 unsigned long retval = 0;
238 int restart = 0;
239
240 if (syscall) {
241 continue_addr = regs->pc;
242 restart_addr = continue_addr - 4;
243 retval = regs->gpr[11];
244
245 /*
246 * Setup syscall restart here so that a debugger will
247 * see the already changed PC.
248 */
249 switch (retval) {
250 case -ERESTART_RESTARTBLOCK:
251 restart = -2;
252 fallthrough;
253 case -ERESTARTNOHAND:
254 case -ERESTARTSYS:
255 case -ERESTARTNOINTR:
256 restart++;
257 regs->gpr[11] = regs->orig_gpr11;
258 regs->pc = restart_addr;
259 break;
260 }
261 }
262
263 /*
264 * Get the signal to deliver. During the call to get_signal the
265 * debugger may change all our registers so we may need to revert
266 * the decision to restart the syscall; specifically, if the PC is
267 * changed, don't restart the syscall.
268 */
269 if (get_signal(&ksig)) {
270 if (unlikely(restart) && regs->pc == restart_addr) {
271 if (retval == -ERESTARTNOHAND ||
272 retval == -ERESTART_RESTARTBLOCK
273 || (retval == -ERESTARTSYS
274 && !(ksig.ka.sa.sa_flags & SA_RESTART))) {
275 /* No automatic restart */
276 regs->gpr[11] = -EINTR;
277 regs->pc = continue_addr;
278 }
279 }
280 handle_signal(&ksig, regs);
281 } else {
282 /* no handler */
283 restore_saved_sigmask();
284 /*
285 * Restore pt_regs PC as syscall restart will be handled by
286 * kernel without return to userspace
287 */
288 if (unlikely(restart) && regs->pc == restart_addr) {
289 regs->pc = continue_addr;
290 return restart;
291 }
292 }
293
294 return 0;
295}
296
297asmlinkage int
298do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
299{
300 do {
301 if (likely(thread_flags & _TIF_NEED_RESCHED)) {
302 schedule();
303 } else {
304 if (unlikely(!user_mode(regs)))
305 return 0;
306 local_irq_enable();
307 if (thread_flags & (_TIF_SIGPENDING|_TIF_NOTIFY_SIGNAL)) {
308 int restart = do_signal(regs, syscall);
309 if (unlikely(restart)) {
310 /*
311 * Restart without handlers.
312 * Deal with it without leaving
313 * the kernel space.
314 */
315 return restart;
316 }
317 syscall = 0;
318 } else {
319 resume_user_mode_work(regs);
320 }
321 }
322 local_irq_disable();
323 thread_flags = read_thread_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/resume_user_mode.h>
25
26#include <asm/fpu.h>
27#include <asm/processor.h>
28#include <asm/syscall.h>
29#include <asm/ucontext.h>
30#include <linux/uaccess.h>
31
32struct rt_sigframe {
33 struct siginfo info;
34 struct ucontext uc;
35 unsigned char retcode[16]; /* trampoline code */
36};
37
38asmlinkage long _sys_rt_sigreturn(struct pt_regs *regs);
39
40asmlinkage int do_work_pending(struct pt_regs *regs, unsigned int thread_flags,
41 int syscall);
42
43#ifdef CONFIG_FPU
44static long restore_fp_state(struct sigcontext __user *sc)
45{
46 long err;
47
48 err = __copy_from_user(¤t->thread.fpcsr, &sc->fpcsr, sizeof(unsigned long));
49 if (unlikely(err))
50 return err;
51
52 /* Restore the FPU state */
53 restore_fpu(current);
54
55 return 0;
56}
57
58static long save_fp_state(struct sigcontext __user *sc)
59{
60 long err;
61
62 /* Sync the user FPU state so we can copy to sigcontext */
63 save_fpu(current);
64
65 err = __copy_to_user(&sc->fpcsr, ¤t->thread.fpcsr, sizeof(unsigned long));
66
67 return err;
68}
69#else
70#define save_fp_state(sc) (0)
71#define restore_fp_state(sc) (0)
72#endif
73
74static int restore_sigcontext(struct pt_regs *regs,
75 struct sigcontext __user *sc)
76{
77 int err = 0;
78
79 /* Always make any pending restarted system calls return -EINTR */
80 current->restart_block.fn = do_no_restart_syscall;
81
82 /*
83 * Restore the regs from &sc->regs.
84 * (sc is already checked since the sigframe was
85 * checked in sys_sigreturn previously)
86 */
87 err |= __copy_from_user(regs, sc->regs.gpr, 32 * sizeof(unsigned long));
88 err |= __copy_from_user(®s->pc, &sc->regs.pc, sizeof(unsigned long));
89 err |= __copy_from_user(®s->sr, &sc->regs.sr, sizeof(unsigned long));
90 err |= restore_fp_state(sc);
91
92 /* make sure the SM-bit is cleared so user-mode cannot fool us */
93 regs->sr &= ~SPR_SR_SM;
94
95 regs->orig_gpr11 = -1; /* Avoid syscall restart checks */
96
97 /* TODO: the other ports use regs->orig_XX to disable syscall checks
98 * after this completes, but we don't use that mechanism. maybe we can
99 * use it now ?
100 */
101
102 return err;
103}
104
105asmlinkage long _sys_rt_sigreturn(struct pt_regs *regs)
106{
107 struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->sp;
108 sigset_t set;
109
110 /*
111 * Since we stacked the signal on a dword boundary,
112 * then frame should be dword aligned here. If it's
113 * not, then the user is trying to mess with us.
114 */
115 if (((unsigned long)frame) & 3)
116 goto badframe;
117
118 if (!access_ok(frame, sizeof(*frame)))
119 goto badframe;
120 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
121 goto badframe;
122
123 set_current_blocked(&set);
124
125 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
126 goto badframe;
127
128 if (restore_altstack(&frame->uc.uc_stack))
129 goto badframe;
130
131 return regs->gpr[11];
132
133badframe:
134 force_sig(SIGSEGV);
135 return 0;
136}
137
138/*
139 * Set up a signal frame.
140 */
141
142static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
143{
144 int err = 0;
145
146 /* copy the regs */
147 /* There should be no need to save callee-saved registers here...
148 * ...but we save them anyway. Revisit this
149 */
150 err |= __copy_to_user(sc->regs.gpr, regs, 32 * sizeof(unsigned long));
151 err |= __copy_to_user(&sc->regs.pc, ®s->pc, sizeof(unsigned long));
152 err |= __copy_to_user(&sc->regs.sr, ®s->sr, sizeof(unsigned long));
153 err |= save_fp_state(sc);
154
155 return err;
156}
157
158static inline unsigned long align_sigframe(unsigned long sp)
159{
160 return sp & ~3UL;
161}
162
163/*
164 * Work out where the signal frame should go. It's either on the user stack
165 * or the alternate stack.
166 */
167
168static inline void __user *get_sigframe(struct ksignal *ksig,
169 struct pt_regs *regs, size_t frame_size)
170{
171 unsigned long sp = regs->sp;
172
173 /* redzone */
174 sp -= STACK_FRAME_OVERHEAD;
175 sp = sigsp(sp, ksig);
176 sp = align_sigframe(sp - frame_size);
177
178 return (void __user *)sp;
179}
180
181/* grab and setup a signal frame.
182 *
183 * basically we stack a lot of state info, and arrange for the
184 * user-mode program to return to the kernel using either a
185 * trampoline which performs the syscall sigreturn, or a provided
186 * user-mode trampoline.
187 */
188static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
189 struct pt_regs *regs)
190{
191 struct rt_sigframe __user *frame;
192 unsigned long return_ip;
193 int err = 0;
194
195 frame = get_sigframe(ksig, regs, sizeof(*frame));
196
197 if (!access_ok(frame, sizeof(*frame)))
198 return -EFAULT;
199
200 /* Create siginfo. */
201 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
202 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
203
204 /* Create the ucontext. */
205 err |= __put_user(0, &frame->uc.uc_flags);
206 err |= __put_user(NULL, &frame->uc.uc_link);
207 err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
208 err |= setup_sigcontext(regs, &frame->uc.uc_mcontext);
209
210 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
211
212 if (err)
213 return -EFAULT;
214
215 /* trampoline - the desired return ip is the retcode itself */
216 return_ip = (unsigned long)&frame->retcode;
217 /* This is:
218 l.ori r11,r0,__NR_sigreturn
219 l.sys 1
220 */
221 err |= __put_user(0xa960, (short __user *)(frame->retcode + 0));
222 err |= __put_user(__NR_rt_sigreturn, (short __user *)(frame->retcode + 2));
223 err |= __put_user(0x20000001, (unsigned long __user *)(frame->retcode + 4));
224 err |= __put_user(0x15000000, (unsigned long __user *)(frame->retcode + 8));
225
226 if (err)
227 return -EFAULT;
228
229 /* Set up registers for signal handler */
230 regs->pc = (unsigned long)ksig->ka.sa.sa_handler; /* what we enter NOW */
231 regs->gpr[9] = (unsigned long)return_ip; /* what we enter LATER */
232 regs->gpr[3] = (unsigned long)ksig->sig; /* arg 1: signo */
233 regs->gpr[4] = (unsigned long)&frame->info; /* arg 2: (siginfo_t*) */
234 regs->gpr[5] = (unsigned long)&frame->uc; /* arg 3: ucontext */
235
236 /* actually move the usp to reflect the stacked frame */
237 regs->sp = (unsigned long)frame;
238
239 return 0;
240}
241
242static inline void
243handle_signal(struct ksignal *ksig, struct pt_regs *regs)
244{
245 int ret;
246
247 ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
248
249 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
250}
251
252/*
253 * Note that 'init' is a special process: it doesn't get signals it doesn't
254 * want to handle. Thus you cannot kill init even with a SIGKILL even by
255 * mistake.
256 *
257 * Also note that the regs structure given here as an argument, is the latest
258 * pushed pt_regs. It may or may not be the same as the first pushed registers
259 * when the initial usermode->kernelmode transition took place. Therefore
260 * we can use user_mode(regs) to see if we came directly from kernel or user
261 * mode below.
262 */
263
264static int do_signal(struct pt_regs *regs, int syscall)
265{
266 struct ksignal ksig;
267 unsigned long continue_addr = 0;
268 unsigned long restart_addr = 0;
269 unsigned long retval = 0;
270 int restart = 0;
271
272 if (syscall) {
273 continue_addr = regs->pc;
274 restart_addr = continue_addr - 4;
275 retval = regs->gpr[11];
276
277 /*
278 * Setup syscall restart here so that a debugger will
279 * see the already changed PC.
280 */
281 switch (retval) {
282 case -ERESTART_RESTARTBLOCK:
283 restart = -2;
284 fallthrough;
285 case -ERESTARTNOHAND:
286 case -ERESTARTSYS:
287 case -ERESTARTNOINTR:
288 restart++;
289 regs->gpr[11] = regs->orig_gpr11;
290 regs->pc = restart_addr;
291 break;
292 }
293 }
294
295 /*
296 * Get the signal to deliver. During the call to get_signal the
297 * debugger may change all our registers so we may need to revert
298 * the decision to restart the syscall; specifically, if the PC is
299 * changed, don't restart the syscall.
300 */
301 if (get_signal(&ksig)) {
302 if (unlikely(restart) && regs->pc == restart_addr) {
303 if (retval == -ERESTARTNOHAND ||
304 retval == -ERESTART_RESTARTBLOCK
305 || (retval == -ERESTARTSYS
306 && !(ksig.ka.sa.sa_flags & SA_RESTART))) {
307 /* No automatic restart */
308 regs->gpr[11] = -EINTR;
309 regs->pc = continue_addr;
310 }
311 }
312 handle_signal(&ksig, regs);
313 } else {
314 /* no handler */
315 restore_saved_sigmask();
316 /*
317 * Restore pt_regs PC as syscall restart will be handled by
318 * kernel without return to userspace
319 */
320 if (unlikely(restart) && regs->pc == restart_addr) {
321 regs->pc = continue_addr;
322 return restart;
323 }
324 }
325
326 return 0;
327}
328
329asmlinkage int
330do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
331{
332 do {
333 if (likely(thread_flags & _TIF_NEED_RESCHED)) {
334 schedule();
335 } else {
336 if (unlikely(!user_mode(regs)))
337 return 0;
338 local_irq_enable();
339 if (thread_flags & (_TIF_SIGPENDING|_TIF_NOTIFY_SIGNAL)) {
340 int restart = do_signal(regs, syscall);
341 if (unlikely(restart)) {
342 /*
343 * Restart without handlers.
344 * Deal with it without leaving
345 * the kernel space.
346 */
347 return restart;
348 }
349 syscall = 0;
350 } else {
351 resume_user_mode_work(regs);
352 }
353 }
354 local_irq_disable();
355 thread_flags = read_thread_flags();
356 } while (thread_flags & _TIF_WORK_MASK);
357 return 0;
358}