1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Port on Texas Instruments TMS320C6x architecture
*
* Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
* Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
*
* Updated for 2.6.34: Mark Salter <msalter@redhat.com>
*/
#include <linux/kernel.h>
#include <linux/uaccess.h>
#include <linux/syscalls.h>
#include <linux/tracehook.h>
#include <asm/ucontext.h>
#include <asm/cacheflush.h>
/*
* Do a signal return, undo the signal stack.
*/
#define RETCODE_SIZE (9 << 2) /* 9 instructions = 36 bytes */
struct rt_sigframe {
struct siginfo __user *pinfo;
void __user *puc;
struct siginfo info;
struct ucontext uc;
unsigned long retcode[RETCODE_SIZE >> 2];
};
static int restore_sigcontext(struct pt_regs *regs,
struct sigcontext __user *sc)
{
int err = 0;
/* The access_ok check was done by caller, so use __get_user here */
#define COPY(x) (err |= __get_user(regs->x, &sc->sc_##x))
COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
COPY(a16); COPY(a17); COPY(a18); COPY(a19);
COPY(a20); COPY(a21); COPY(a22); COPY(a23);
COPY(a24); COPY(a25); COPY(a26); COPY(a27);
COPY(a28); COPY(a29); COPY(a30); COPY(a31);
COPY(b16); COPY(b17); COPY(b18); COPY(b19);
COPY(b20); COPY(b21); COPY(b22); COPY(b23);
COPY(b24); COPY(b25); COPY(b26); COPY(b27);
COPY(b28); COPY(b29); COPY(b30); COPY(b31);
COPY(csr); COPY(pc);
#undef COPY
return err;
}
asmlinkage int do_rt_sigreturn(struct pt_regs *regs)
{
struct rt_sigframe __user *frame;
sigset_t set;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
/*
* Since we stacked the signal on a dword boundary,
* 'sp' should be dword aligned here. If it's
* not, then the user is trying to mess with us.
*/
if (regs->sp & 7)
goto badframe;
frame = (struct rt_sigframe __user *) ((unsigned long) regs->sp + 8);
if (!access_ok(frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
goto badframe;
set_current_blocked(&set);
if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
goto badframe;
return regs->a4;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
unsigned long mask)
{
int err = 0;
err |= __put_user(mask, &sc->sc_mask);
/* The access_ok check was done by caller, so use __put_user here */
#define COPY(x) (err |= __put_user(regs->x, &sc->sc_##x))
COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
COPY(a16); COPY(a17); COPY(a18); COPY(a19);
COPY(a20); COPY(a21); COPY(a22); COPY(a23);
COPY(a24); COPY(a25); COPY(a26); COPY(a27);
COPY(a28); COPY(a29); COPY(a30); COPY(a31);
COPY(b16); COPY(b17); COPY(b18); COPY(b19);
COPY(b20); COPY(b21); COPY(b22); COPY(b23);
COPY(b24); COPY(b25); COPY(b26); COPY(b27);
COPY(b28); COPY(b29); COPY(b30); COPY(b31);
COPY(csr); COPY(pc);
#undef COPY
return err;
}
static inline void __user *get_sigframe(struct ksignal *ksig,
struct pt_regs *regs,
unsigned long framesize)
{
unsigned long sp = sigsp(regs->sp, ksig);
/*
* No matter what happens, 'sp' must be dword
* aligned. Otherwise, nasty things will happen
*/
return (void __user *)((sp - framesize) & ~7);
}
static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
struct pt_regs *regs)
{
struct rt_sigframe __user *frame;
unsigned long __user *retcode;
int err = 0;
frame = get_sigframe(ksig, regs, sizeof(*frame));
if (!access_ok(frame, sizeof(*frame)))
return -EFAULT;
err |= __put_user(&frame->info, &frame->pinfo);
err |= __put_user(&frame->uc, &frame->puc);
err |= copy_siginfo_to_user(&frame->info, &ksig->info);
/* Clear all the bits of the ucontext we don't use. */
err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
/* Set up to return from userspace */
retcode = (unsigned long __user *) &frame->retcode;
/* The access_ok check was done above, so use __put_user here */
#define COPY(x) (err |= __put_user(x, retcode++))
COPY(0x0000002AUL | (__NR_rt_sigreturn << 7));
/* MVK __NR_rt_sigreturn,B0 */
COPY(0x10000000UL); /* SWE */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
#undef COPY
if (err)
return -EFAULT;
flush_icache_range((unsigned long) &frame->retcode,
(unsigned long) &frame->retcode + RETCODE_SIZE);
retcode = (unsigned long __user *) &frame->retcode;
/* Change user context to branch to signal handler */
regs->sp = (unsigned long) frame - 8;
regs->b3 = (unsigned long) retcode;
regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
/* Give the signal number to the handler */
regs->a4 = ksig->sig;
/*
* For realtime signals we must also set the second and third
* arguments for the signal handler.
* -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
*/
regs->b4 = (unsigned long)&frame->info;
regs->a6 = (unsigned long)&frame->uc;
return 0;
}
static inline void
handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
{
switch (regs->a4) {
case -ERESTARTNOHAND:
if (!has_handler)
goto do_restart;
regs->a4 = -EINTR;
break;
case -ERESTARTSYS:
if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
regs->a4 = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
do_restart:
regs->a4 = regs->orig_a4;
regs->pc -= 4;
break;
}
}
/*
* handle the actual delivery of a signal to userspace
*/
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs,
int syscall)
{
int ret;
/* Are we from a system call? */
if (syscall) {
/* If so, check system call restarting.. */
switch (regs->a4) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
regs->a4 = -EINTR;
break;
case -ERESTARTSYS:
if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
regs->a4 = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
regs->a4 = regs->orig_a4;
regs->pc -= 4;
}
}
/* Set up the stack frame */
ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
signal_setup_done(ret, ksig, 0);
}
/*
* handle a potential signal
*/
static void do_signal(struct pt_regs *regs, int syscall)
{
struct ksignal ksig;
/* we want the common case to go fast, which is why we may in certain
* cases get here from kernel mode */
if (!user_mode(regs))
return;
if (get_signal(&ksig)) {
handle_signal(&ksig, regs, syscall);
return;
}
/* did we come from a system call? */
if (syscall) {
/* restart the system call - no handlers present */
switch (regs->a4) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
regs->a4 = regs->orig_a4;
regs->pc -= 4;
break;
case -ERESTART_RESTARTBLOCK:
regs->a4 = regs->orig_a4;
regs->b0 = __NR_restart_syscall;
regs->pc -= 4;
break;
}
}
/* if there's no signal to deliver, we just put the saved sigmask
* back */
restore_saved_sigmask();
}
/*
* notification of userspace execution resumption
* - triggered by current->work.notify_resume
*/
asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags,
int syscall)
{
/* deal with pending signal delivery */
if (thread_info_flags & (1 << TIF_SIGPENDING))
do_signal(regs, syscall);
if (thread_info_flags & (1 << TIF_NOTIFY_RESUME)) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
}
|
