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1/*
2 * Signal Handling for ARC
3 *
4 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * vineetg: Jan 2010 (Restarting of timer related syscalls)
11 *
12 * vineetg: Nov 2009 (Everything needed for TIF_RESTORE_SIGMASK)
13 * -do_signal() supports TIF_RESTORE_SIGMASK
14 * -do_signal() no loner needs oldset, required by OLD sys_sigsuspend
15 * -sys_rt_sigsuspend() now comes from generic code, so discard arch implemen
16 * -sys_sigsuspend() no longer needs to fudge ptregs, hence that arg removed
17 * -sys_sigsuspend() no longer loops for do_signal(), sets TIF_xxx and leaves
18 * the job to do_signal()
19 *
20 * vineetg: July 2009
21 * -Modified Code to support the uClibc provided userland sigreturn stub
22 * to avoid kernel synthesing it on user stack at runtime, costing TLB
23 * probes and Cache line flushes.
24 *
25 * vineetg: July 2009
26 * -In stash_usr_regs( ) and restore_usr_regs( ), save/restore of user regs
27 * in done in block copy rather than one word at a time.
28 * This saves around 2K of code and improves LMBench lat_sig <catch>
29 *
30 * rajeshwarr: Feb 2009
31 * - Support for Realtime Signals
32 *
33 * vineetg: Aug 11th 2008: Bug #94183
34 * -ViXS were still seeing crashes when using insmod to load drivers.
35 * It turned out that the code to change Execute permssions for TLB entries
36 * of user was not guarded for interrupts (mod_tlb_permission)
37 * This was causing TLB entries to be overwritten on unrelated indexes
38 *
39 * Vineetg: July 15th 2008: Bug #94183
40 * -Exception happens in Delay slot of a JMP, and before user space resumes,
41 * Signal is delivered (Ctrl + C) = >SIGINT.
42 * setup_frame( ) sets up PC,SP,BLINK to enable user space signal handler
43 * to run, but doesn't clear the Delay slot bit from status32. As a result,
44 * on resuming user mode, signal handler branches off to BTA of orig JMP
45 * -FIX: clear the DE bit from status32 in setup_frame( )
46 *
47 * Rahul Trivedi, Kanika Nema: Codito Technologies 2004
48 */
49
50#include <linux/signal.h>
51#include <linux/ptrace.h>
52#include <linux/personality.h>
53#include <linux/uaccess.h>
54#include <linux/syscalls.h>
55#include <linux/tracehook.h>
56#include <asm/ucontext.h>
57
58struct rt_sigframe {
59 struct siginfo info;
60 struct ucontext uc;
61#define MAGIC_SIGALTSTK 0x07302004
62 unsigned int sigret_magic;
63};
64
65static int
66stash_usr_regs(struct rt_sigframe __user *sf, struct pt_regs *regs,
67 sigset_t *set)
68{
69 int err;
70 struct user_regs_struct uregs;
71
72 uregs.scratch.bta = regs->bta;
73 uregs.scratch.lp_start = regs->lp_start;
74 uregs.scratch.lp_end = regs->lp_end;
75 uregs.scratch.lp_count = regs->lp_count;
76 uregs.scratch.status32 = regs->status32;
77 uregs.scratch.ret = regs->ret;
78 uregs.scratch.blink = regs->blink;
79 uregs.scratch.fp = regs->fp;
80 uregs.scratch.gp = regs->r26;
81 uregs.scratch.r12 = regs->r12;
82 uregs.scratch.r11 = regs->r11;
83 uregs.scratch.r10 = regs->r10;
84 uregs.scratch.r9 = regs->r9;
85 uregs.scratch.r8 = regs->r8;
86 uregs.scratch.r7 = regs->r7;
87 uregs.scratch.r6 = regs->r6;
88 uregs.scratch.r5 = regs->r5;
89 uregs.scratch.r4 = regs->r4;
90 uregs.scratch.r3 = regs->r3;
91 uregs.scratch.r2 = regs->r2;
92 uregs.scratch.r1 = regs->r1;
93 uregs.scratch.r0 = regs->r0;
94 uregs.scratch.sp = regs->sp;
95
96 err = __copy_to_user(&(sf->uc.uc_mcontext.regs.scratch), &uregs.scratch,
97 sizeof(sf->uc.uc_mcontext.regs.scratch));
98 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(sigset_t));
99
100 return err;
101}
102
103static int restore_usr_regs(struct pt_regs *regs, struct rt_sigframe __user *sf)
104{
105 sigset_t set;
106 int err;
107 struct user_regs_struct uregs;
108
109 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
110 err |= __copy_from_user(&uregs.scratch,
111 &(sf->uc.uc_mcontext.regs.scratch),
112 sizeof(sf->uc.uc_mcontext.regs.scratch));
113 if (err)
114 return err;
115
116 set_current_blocked(&set);
117 regs->bta = uregs.scratch.bta;
118 regs->lp_start = uregs.scratch.lp_start;
119 regs->lp_end = uregs.scratch.lp_end;
120 regs->lp_count = uregs.scratch.lp_count;
121 regs->status32 = uregs.scratch.status32;
122 regs->ret = uregs.scratch.ret;
123 regs->blink = uregs.scratch.blink;
124 regs->fp = uregs.scratch.fp;
125 regs->r26 = uregs.scratch.gp;
126 regs->r12 = uregs.scratch.r12;
127 regs->r11 = uregs.scratch.r11;
128 regs->r10 = uregs.scratch.r10;
129 regs->r9 = uregs.scratch.r9;
130 regs->r8 = uregs.scratch.r8;
131 regs->r7 = uregs.scratch.r7;
132 regs->r6 = uregs.scratch.r6;
133 regs->r5 = uregs.scratch.r5;
134 regs->r4 = uregs.scratch.r4;
135 regs->r3 = uregs.scratch.r3;
136 regs->r2 = uregs.scratch.r2;
137 regs->r1 = uregs.scratch.r1;
138 regs->r0 = uregs.scratch.r0;
139 regs->sp = uregs.scratch.sp;
140
141 return 0;
142}
143
144static inline int is_do_ss_needed(unsigned int magic)
145{
146 if (MAGIC_SIGALTSTK == magic)
147 return 1;
148 else
149 return 0;
150}
151
152SYSCALL_DEFINE0(rt_sigreturn)
153{
154 struct rt_sigframe __user *sf;
155 unsigned int magic;
156 struct pt_regs *regs = current_pt_regs();
157
158 /* Always make any pending restarted system calls return -EINTR */
159 current->restart_block.fn = do_no_restart_syscall;
160
161 /* Since we stacked the signal on a word boundary,
162 * then 'sp' should be word aligned here. If it's
163 * not, then the user is trying to mess with us.
164 */
165 if (regs->sp & 3)
166 goto badframe;
167
168 sf = (struct rt_sigframe __force __user *)(regs->sp);
169
170 if (!access_ok(VERIFY_READ, sf, sizeof(*sf)))
171 goto badframe;
172
173 if (__get_user(magic, &sf->sigret_magic))
174 goto badframe;
175
176 if (unlikely(is_do_ss_needed(magic)))
177 if (restore_altstack(&sf->uc.uc_stack))
178 goto badframe;
179
180 if (restore_usr_regs(regs, sf))
181 goto badframe;
182
183 /* Don't restart from sigreturn */
184 syscall_wont_restart(regs);
185
186 /*
187 * Ensure that sigreturn always returns to user mode (in case the
188 * regs saved on user stack got fudged between save and sigreturn)
189 * Otherwise it is easy to panic the kernel with a custom
190 * signal handler and/or restorer which clobberes the status32/ret
191 * to return to a bogus location in kernel mode.
192 */
193 regs->status32 |= STATUS_U_MASK;
194
195 return regs->r0;
196
197badframe:
198 force_sig(SIGSEGV, current);
199 return 0;
200}
201
202/*
203 * Determine which stack to use..
204 */
205static inline void __user *get_sigframe(struct ksignal *ksig,
206 struct pt_regs *regs,
207 unsigned long framesize)
208{
209 unsigned long sp = sigsp(regs->sp, ksig);
210 void __user *frame;
211
212 /* No matter what happens, 'sp' must be word
213 * aligned otherwise nasty things could happen
214 */
215
216 /* ATPCS B01 mandates 8-byte alignment */
217 frame = (void __user *)((sp - framesize) & ~7);
218
219 /* Check that we can actually write to the signal frame */
220 if (!access_ok(VERIFY_WRITE, frame, framesize))
221 frame = NULL;
222
223 return frame;
224}
225
226static int
227setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
228{
229 struct rt_sigframe __user *sf;
230 unsigned int magic = 0;
231 int err = 0;
232
233 sf = get_sigframe(ksig, regs, sizeof(struct rt_sigframe));
234 if (!sf)
235 return 1;
236
237 /*
238 * w/o SA_SIGINFO, struct ucontext is partially populated (only
239 * uc_mcontext/uc_sigmask) for kernel's normal user state preservation
240 * during signal handler execution. This works for SA_SIGINFO as well
241 * although the semantics are now overloaded (the same reg state can be
242 * inspected by userland: but are they allowed to fiddle with it ?
243 */
244 err |= stash_usr_regs(sf, regs, set);
245
246 /*
247 * SA_SIGINFO requires 3 args to signal handler:
248 * #1: sig-no (common to any handler)
249 * #2: struct siginfo
250 * #3: struct ucontext (completely populated)
251 */
252 if (unlikely(ksig->ka.sa.sa_flags & SA_SIGINFO)) {
253 err |= copy_siginfo_to_user(&sf->info, &ksig->info);
254 err |= __put_user(0, &sf->uc.uc_flags);
255 err |= __put_user(NULL, &sf->uc.uc_link);
256 err |= __save_altstack(&sf->uc.uc_stack, regs->sp);
257
258 /* setup args 2 and 3 for user mode handler */
259 regs->r1 = (unsigned long)&sf->info;
260 regs->r2 = (unsigned long)&sf->uc;
261
262 /*
263 * small optim to avoid unconditonally calling do_sigaltstack
264 * in sigreturn path, now that we only have rt_sigreturn
265 */
266 magic = MAGIC_SIGALTSTK;
267 }
268
269 err |= __put_user(magic, &sf->sigret_magic);
270 if (err)
271 return err;
272
273 /* #1 arg to the user Signal handler */
274 regs->r0 = ksig->sig;
275
276 /* setup PC of user space signal handler */
277 regs->ret = (unsigned long)ksig->ka.sa.sa_handler;
278
279 /*
280 * handler returns using sigreturn stub provided already by userpsace
281 * If not, nuke the process right away
282 */
283 if(!(ksig->ka.sa.sa_flags & SA_RESTORER))
284 return 1;
285
286 regs->blink = (unsigned long)ksig->ka.sa.sa_restorer;
287
288 /* User Stack for signal handler will be above the frame just carved */
289 regs->sp = (unsigned long)sf;
290
291 /*
292 * Bug 94183, Clear the DE bit, so that when signal handler
293 * starts to run, it doesn't use BTA
294 */
295 regs->status32 &= ~STATUS_DE_MASK;
296 regs->status32 |= STATUS_L_MASK;
297
298 return err;
299}
300
301static void arc_restart_syscall(struct k_sigaction *ka, struct pt_regs *regs)
302{
303 switch (regs->r0) {
304 case -ERESTART_RESTARTBLOCK:
305 case -ERESTARTNOHAND:
306 /*
307 * ERESTARTNOHAND means that the syscall should
308 * only be restarted if there was no handler for
309 * the signal, and since we only get here if there
310 * is a handler, we don't restart
311 */
312 regs->r0 = -EINTR; /* ERESTART_xxx is internal */
313 break;
314
315 case -ERESTARTSYS:
316 /*
317 * ERESTARTSYS means to restart the syscall if
318 * there is no handler or the handler was
319 * registered with SA_RESTART
320 */
321 if (!(ka->sa.sa_flags & SA_RESTART)) {
322 regs->r0 = -EINTR;
323 break;
324 }
325 /* fallthrough */
326
327 case -ERESTARTNOINTR:
328 /*
329 * ERESTARTNOINTR means that the syscall should
330 * be called again after the signal handler returns.
331 * Setup reg state just as it was before doing the trap
332 * r0 has been clobbered with sys call ret code thus it
333 * needs to be reloaded with orig first arg to syscall
334 * in orig_r0. Rest of relevant reg-file:
335 * r8 (syscall num) and (r1 - r7) will be reset to
336 * their orig user space value when we ret from kernel
337 */
338 regs->r0 = regs->orig_r0;
339 regs->ret -= is_isa_arcv2() ? 2 : 4;
340 break;
341 }
342}
343
344/*
345 * OK, we're invoking a handler
346 */
347static void
348handle_signal(struct ksignal *ksig, struct pt_regs *regs)
349{
350 sigset_t *oldset = sigmask_to_save();
351 int failed;
352
353 /* Set up the stack frame */
354 failed = setup_rt_frame(ksig, oldset, regs);
355
356 signal_setup_done(failed, ksig, 0);
357}
358
359void do_signal(struct pt_regs *regs)
360{
361 struct ksignal ksig;
362 int restart_scall;
363
364 restart_scall = in_syscall(regs) && syscall_restartable(regs);
365
366 if (get_signal(&ksig)) {
367 if (restart_scall) {
368 arc_restart_syscall(&ksig.ka, regs);
369 syscall_wont_restart(regs); /* No more restarts */
370 }
371 handle_signal(&ksig, regs);
372 return;
373 }
374
375 if (restart_scall) {
376 /* No handler for syscall: restart it */
377 if (regs->r0 == -ERESTARTNOHAND ||
378 regs->r0 == -ERESTARTSYS || regs->r0 == -ERESTARTNOINTR) {
379 regs->r0 = regs->orig_r0;
380 regs->ret -= is_isa_arcv2() ? 2 : 4;
381 } else if (regs->r0 == -ERESTART_RESTARTBLOCK) {
382 regs->r8 = __NR_restart_syscall;
383 regs->ret -= is_isa_arcv2() ? 2 : 4;
384 }
385 syscall_wont_restart(regs); /* No more restarts */
386 }
387
388 /* If there's no signal to deliver, restore the saved sigmask back */
389 restore_saved_sigmask();
390}
391
392void do_notify_resume(struct pt_regs *regs)
393{
394 /*
395 * ASM glue gaurantees that this is only called when returning to
396 * user mode
397 */
398 if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
399 tracehook_notify_resume(regs);
400}
1/*
2 * Signal Handling for ARC
3 *
4 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * vineetg: Jan 2010 (Restarting of timer related syscalls)
11 *
12 * vineetg: Nov 2009 (Everything needed for TIF_RESTORE_SIGMASK)
13 * -do_signal() supports TIF_RESTORE_SIGMASK
14 * -do_signal() no loner needs oldset, required by OLD sys_sigsuspend
15 * -sys_rt_sigsuspend() now comes from generic code, so discard arch implemen
16 * -sys_sigsuspend() no longer needs to fudge ptregs, hence that arg removed
17 * -sys_sigsuspend() no longer loops for do_signal(), sets TIF_xxx and leaves
18 * the job to do_signal()
19 *
20 * vineetg: July 2009
21 * -Modified Code to support the uClibc provided userland sigreturn stub
22 * to avoid kernel synthesing it on user stack at runtime, costing TLB
23 * probes and Cache line flushes.
24 *
25 * vineetg: July 2009
26 * -In stash_usr_regs( ) and restore_usr_regs( ), save/restore of user regs
27 * in done in block copy rather than one word at a time.
28 * This saves around 2K of code and improves LMBench lat_sig <catch>
29 *
30 * rajeshwarr: Feb 2009
31 * - Support for Realtime Signals
32 *
33 * vineetg: Aug 11th 2008: Bug #94183
34 * -ViXS were still seeing crashes when using insmod to load drivers.
35 * It turned out that the code to change Execute permssions for TLB entries
36 * of user was not guarded for interrupts (mod_tlb_permission)
37 * This was causing TLB entries to be overwritten on unrelated indexes
38 *
39 * Vineetg: July 15th 2008: Bug #94183
40 * -Exception happens in Delay slot of a JMP, and before user space resumes,
41 * Signal is delivered (Ctrl + C) = >SIGINT.
42 * setup_frame( ) sets up PC,SP,BLINK to enable user space signal handler
43 * to run, but doesn't clear the Delay slot bit from status32. As a result,
44 * on resuming user mode, signal handler branches off to BTA of orig JMP
45 * -FIX: clear the DE bit from status32 in setup_frame( )
46 *
47 * Rahul Trivedi, Kanika Nema: Codito Technologies 2004
48 */
49
50#include <linux/signal.h>
51#include <linux/ptrace.h>
52#include <linux/personality.h>
53#include <linux/uaccess.h>
54#include <linux/syscalls.h>
55#include <linux/tracehook.h>
56#include <linux/sched/task_stack.h>
57
58#include <asm/ucontext.h>
59
60struct rt_sigframe {
61 struct siginfo info;
62 struct ucontext uc;
63#define MAGIC_SIGALTSTK 0x07302004
64 unsigned int sigret_magic;
65};
66
67static int
68stash_usr_regs(struct rt_sigframe __user *sf, struct pt_regs *regs,
69 sigset_t *set)
70{
71 int err;
72 struct user_regs_struct uregs;
73
74 uregs.scratch.bta = regs->bta;
75 uregs.scratch.lp_start = regs->lp_start;
76 uregs.scratch.lp_end = regs->lp_end;
77 uregs.scratch.lp_count = regs->lp_count;
78 uregs.scratch.status32 = regs->status32;
79 uregs.scratch.ret = regs->ret;
80 uregs.scratch.blink = regs->blink;
81 uregs.scratch.fp = regs->fp;
82 uregs.scratch.gp = regs->r26;
83 uregs.scratch.r12 = regs->r12;
84 uregs.scratch.r11 = regs->r11;
85 uregs.scratch.r10 = regs->r10;
86 uregs.scratch.r9 = regs->r9;
87 uregs.scratch.r8 = regs->r8;
88 uregs.scratch.r7 = regs->r7;
89 uregs.scratch.r6 = regs->r6;
90 uregs.scratch.r5 = regs->r5;
91 uregs.scratch.r4 = regs->r4;
92 uregs.scratch.r3 = regs->r3;
93 uregs.scratch.r2 = regs->r2;
94 uregs.scratch.r1 = regs->r1;
95 uregs.scratch.r0 = regs->r0;
96 uregs.scratch.sp = regs->sp;
97
98 err = __copy_to_user(&(sf->uc.uc_mcontext.regs.scratch), &uregs.scratch,
99 sizeof(sf->uc.uc_mcontext.regs.scratch));
100 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(sigset_t));
101
102 return err;
103}
104
105static int restore_usr_regs(struct pt_regs *regs, struct rt_sigframe __user *sf)
106{
107 sigset_t set;
108 int err;
109 struct user_regs_struct uregs;
110
111 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
112 err |= __copy_from_user(&uregs.scratch,
113 &(sf->uc.uc_mcontext.regs.scratch),
114 sizeof(sf->uc.uc_mcontext.regs.scratch));
115 if (err)
116 return err;
117
118 set_current_blocked(&set);
119 regs->bta = uregs.scratch.bta;
120 regs->lp_start = uregs.scratch.lp_start;
121 regs->lp_end = uregs.scratch.lp_end;
122 regs->lp_count = uregs.scratch.lp_count;
123 regs->status32 = uregs.scratch.status32;
124 regs->ret = uregs.scratch.ret;
125 regs->blink = uregs.scratch.blink;
126 regs->fp = uregs.scratch.fp;
127 regs->r26 = uregs.scratch.gp;
128 regs->r12 = uregs.scratch.r12;
129 regs->r11 = uregs.scratch.r11;
130 regs->r10 = uregs.scratch.r10;
131 regs->r9 = uregs.scratch.r9;
132 regs->r8 = uregs.scratch.r8;
133 regs->r7 = uregs.scratch.r7;
134 regs->r6 = uregs.scratch.r6;
135 regs->r5 = uregs.scratch.r5;
136 regs->r4 = uregs.scratch.r4;
137 regs->r3 = uregs.scratch.r3;
138 regs->r2 = uregs.scratch.r2;
139 regs->r1 = uregs.scratch.r1;
140 regs->r0 = uregs.scratch.r0;
141 regs->sp = uregs.scratch.sp;
142
143 return 0;
144}
145
146static inline int is_do_ss_needed(unsigned int magic)
147{
148 if (MAGIC_SIGALTSTK == magic)
149 return 1;
150 else
151 return 0;
152}
153
154SYSCALL_DEFINE0(rt_sigreturn)
155{
156 struct rt_sigframe __user *sf;
157 unsigned int magic;
158 struct pt_regs *regs = current_pt_regs();
159
160 /* Always make any pending restarted system calls return -EINTR */
161 current->restart_block.fn = do_no_restart_syscall;
162
163 /* Since we stacked the signal on a word boundary,
164 * then 'sp' should be word aligned here. If it's
165 * not, then the user is trying to mess with us.
166 */
167 if (regs->sp & 3)
168 goto badframe;
169
170 sf = (struct rt_sigframe __force __user *)(regs->sp);
171
172 if (!access_ok(VERIFY_READ, sf, sizeof(*sf)))
173 goto badframe;
174
175 if (__get_user(magic, &sf->sigret_magic))
176 goto badframe;
177
178 if (unlikely(is_do_ss_needed(magic)))
179 if (restore_altstack(&sf->uc.uc_stack))
180 goto badframe;
181
182 if (restore_usr_regs(regs, sf))
183 goto badframe;
184
185 /* Don't restart from sigreturn */
186 syscall_wont_restart(regs);
187
188 /*
189 * Ensure that sigreturn always returns to user mode (in case the
190 * regs saved on user stack got fudged between save and sigreturn)
191 * Otherwise it is easy to panic the kernel with a custom
192 * signal handler and/or restorer which clobberes the status32/ret
193 * to return to a bogus location in kernel mode.
194 */
195 regs->status32 |= STATUS_U_MASK;
196
197 return regs->r0;
198
199badframe:
200 force_sig(SIGSEGV, current);
201 return 0;
202}
203
204/*
205 * Determine which stack to use..
206 */
207static inline void __user *get_sigframe(struct ksignal *ksig,
208 struct pt_regs *regs,
209 unsigned long framesize)
210{
211 unsigned long sp = sigsp(regs->sp, ksig);
212 void __user *frame;
213
214 /* No matter what happens, 'sp' must be word
215 * aligned otherwise nasty things could happen
216 */
217
218 /* ATPCS B01 mandates 8-byte alignment */
219 frame = (void __user *)((sp - framesize) & ~7);
220
221 /* Check that we can actually write to the signal frame */
222 if (!access_ok(VERIFY_WRITE, frame, framesize))
223 frame = NULL;
224
225 return frame;
226}
227
228static int
229setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
230{
231 struct rt_sigframe __user *sf;
232 unsigned int magic = 0;
233 int err = 0;
234
235 sf = get_sigframe(ksig, regs, sizeof(struct rt_sigframe));
236 if (!sf)
237 return 1;
238
239 /*
240 * w/o SA_SIGINFO, struct ucontext is partially populated (only
241 * uc_mcontext/uc_sigmask) for kernel's normal user state preservation
242 * during signal handler execution. This works for SA_SIGINFO as well
243 * although the semantics are now overloaded (the same reg state can be
244 * inspected by userland: but are they allowed to fiddle with it ?
245 */
246 err |= stash_usr_regs(sf, regs, set);
247
248 /*
249 * SA_SIGINFO requires 3 args to signal handler:
250 * #1: sig-no (common to any handler)
251 * #2: struct siginfo
252 * #3: struct ucontext (completely populated)
253 */
254 if (unlikely(ksig->ka.sa.sa_flags & SA_SIGINFO)) {
255 err |= copy_siginfo_to_user(&sf->info, &ksig->info);
256 err |= __put_user(0, &sf->uc.uc_flags);
257 err |= __put_user(NULL, &sf->uc.uc_link);
258 err |= __save_altstack(&sf->uc.uc_stack, regs->sp);
259
260 /* setup args 2 and 3 for user mode handler */
261 regs->r1 = (unsigned long)&sf->info;
262 regs->r2 = (unsigned long)&sf->uc;
263
264 /*
265 * small optim to avoid unconditonally calling do_sigaltstack
266 * in sigreturn path, now that we only have rt_sigreturn
267 */
268 magic = MAGIC_SIGALTSTK;
269 }
270
271 err |= __put_user(magic, &sf->sigret_magic);
272 if (err)
273 return err;
274
275 /* #1 arg to the user Signal handler */
276 regs->r0 = ksig->sig;
277
278 /* setup PC of user space signal handler */
279 regs->ret = (unsigned long)ksig->ka.sa.sa_handler;
280
281 /*
282 * handler returns using sigreturn stub provided already by userpsace
283 * If not, nuke the process right away
284 */
285 if(!(ksig->ka.sa.sa_flags & SA_RESTORER))
286 return 1;
287
288 regs->blink = (unsigned long)ksig->ka.sa.sa_restorer;
289
290 /* User Stack for signal handler will be above the frame just carved */
291 regs->sp = (unsigned long)sf;
292
293 /*
294 * Bug 94183, Clear the DE bit, so that when signal handler
295 * starts to run, it doesn't use BTA
296 */
297 regs->status32 &= ~STATUS_DE_MASK;
298 regs->status32 |= STATUS_L_MASK;
299
300 return err;
301}
302
303static void arc_restart_syscall(struct k_sigaction *ka, struct pt_regs *regs)
304{
305 switch (regs->r0) {
306 case -ERESTART_RESTARTBLOCK:
307 case -ERESTARTNOHAND:
308 /*
309 * ERESTARTNOHAND means that the syscall should
310 * only be restarted if there was no handler for
311 * the signal, and since we only get here if there
312 * is a handler, we don't restart
313 */
314 regs->r0 = -EINTR; /* ERESTART_xxx is internal */
315 break;
316
317 case -ERESTARTSYS:
318 /*
319 * ERESTARTSYS means to restart the syscall if
320 * there is no handler or the handler was
321 * registered with SA_RESTART
322 */
323 if (!(ka->sa.sa_flags & SA_RESTART)) {
324 regs->r0 = -EINTR;
325 break;
326 }
327 /* fallthrough */
328
329 case -ERESTARTNOINTR:
330 /*
331 * ERESTARTNOINTR means that the syscall should
332 * be called again after the signal handler returns.
333 * Setup reg state just as it was before doing the trap
334 * r0 has been clobbered with sys call ret code thus it
335 * needs to be reloaded with orig first arg to syscall
336 * in orig_r0. Rest of relevant reg-file:
337 * r8 (syscall num) and (r1 - r7) will be reset to
338 * their orig user space value when we ret from kernel
339 */
340 regs->r0 = regs->orig_r0;
341 regs->ret -= is_isa_arcv2() ? 2 : 4;
342 break;
343 }
344}
345
346/*
347 * OK, we're invoking a handler
348 */
349static void
350handle_signal(struct ksignal *ksig, struct pt_regs *regs)
351{
352 sigset_t *oldset = sigmask_to_save();
353 int failed;
354
355 /* Set up the stack frame */
356 failed = setup_rt_frame(ksig, oldset, regs);
357
358 signal_setup_done(failed, ksig, 0);
359}
360
361void do_signal(struct pt_regs *regs)
362{
363 struct ksignal ksig;
364 int restart_scall;
365
366 restart_scall = in_syscall(regs) && syscall_restartable(regs);
367
368 if (get_signal(&ksig)) {
369 if (restart_scall) {
370 arc_restart_syscall(&ksig.ka, regs);
371 syscall_wont_restart(regs); /* No more restarts */
372 }
373 handle_signal(&ksig, regs);
374 return;
375 }
376
377 if (restart_scall) {
378 /* No handler for syscall: restart it */
379 if (regs->r0 == -ERESTARTNOHAND ||
380 regs->r0 == -ERESTARTSYS || regs->r0 == -ERESTARTNOINTR) {
381 regs->r0 = regs->orig_r0;
382 regs->ret -= is_isa_arcv2() ? 2 : 4;
383 } else if (regs->r0 == -ERESTART_RESTARTBLOCK) {
384 regs->r8 = __NR_restart_syscall;
385 regs->ret -= is_isa_arcv2() ? 2 : 4;
386 }
387 syscall_wont_restart(regs); /* No more restarts */
388 }
389
390 /* If there's no signal to deliver, restore the saved sigmask back */
391 restore_saved_sigmask();
392}
393
394void do_notify_resume(struct pt_regs *regs)
395{
396 /*
397 * ASM glue gaurantees that this is only called when returning to
398 * user mode
399 */
400 if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
401 tracehook_notify_resume(regs);
402}