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
324
325
326
327
|
/*
* Copyright (C) 2013-2014 Altera Corporation
* Copyright (C) 2011-2012 Tobias Klauser <tklauser@distanz.ch>
* Copyright (C) 2004 Microtronix Datacom Ltd
* Copyright (C) 1991, 1992 Linus Torvalds
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of this archive
* for more details.
*/
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/uaccess.h>
#include <linux/unistd.h>
#include <linux/personality.h>
#include <linux/tracehook.h>
#include <asm/ucontext.h>
#include <asm/cacheflush.h>
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
/*
* Do a signal return; undo the signal stack.
*
* Keep the return code on the stack quadword aligned!
* That makes the cache flush below easier.
*/
struct rt_sigframe {
struct siginfo info;
struct ucontext uc;
};
static inline int rt_restore_ucontext(struct pt_regs *regs,
struct switch_stack *sw,
struct ucontext __user *uc, int *pr2)
{
int temp;
unsigned long __user *gregs = uc->uc_mcontext.gregs;
int err;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
err = __get_user(temp, &uc->uc_mcontext.version);
if (temp != MCONTEXT_VERSION)
goto badframe;
/* restore passed registers */
err |= __get_user(regs->r1, &gregs[0]);
err |= __get_user(regs->r2, &gregs[1]);
err |= __get_user(regs->r3, &gregs[2]);
err |= __get_user(regs->r4, &gregs[3]);
err |= __get_user(regs->r5, &gregs[4]);
err |= __get_user(regs->r6, &gregs[5]);
err |= __get_user(regs->r7, &gregs[6]);
err |= __get_user(regs->r8, &gregs[7]);
err |= __get_user(regs->r9, &gregs[8]);
err |= __get_user(regs->r10, &gregs[9]);
err |= __get_user(regs->r11, &gregs[10]);
err |= __get_user(regs->r12, &gregs[11]);
err |= __get_user(regs->r13, &gregs[12]);
err |= __get_user(regs->r14, &gregs[13]);
err |= __get_user(regs->r15, &gregs[14]);
err |= __get_user(sw->r16, &gregs[15]);
err |= __get_user(sw->r17, &gregs[16]);
err |= __get_user(sw->r18, &gregs[17]);
err |= __get_user(sw->r19, &gregs[18]);
err |= __get_user(sw->r20, &gregs[19]);
err |= __get_user(sw->r21, &gregs[20]);
err |= __get_user(sw->r22, &gregs[21]);
err |= __get_user(sw->r23, &gregs[22]);
/* gregs[23] is handled below */
err |= __get_user(sw->fp, &gregs[24]); /* Verify, should this be
settable */
err |= __get_user(sw->gp, &gregs[25]); /* Verify, should this be
settable */
err |= __get_user(temp, &gregs[26]); /* Not really necessary no user
settable bits */
err |= __get_user(regs->ea, &gregs[27]);
err |= __get_user(regs->ra, &gregs[23]);
err |= __get_user(regs->sp, &gregs[28]);
regs->orig_r2 = -1; /* disable syscall checks */
err |= restore_altstack(&uc->uc_stack);
if (err)
goto badframe;
*pr2 = regs->r2;
return err;
badframe:
return 1;
}
asmlinkage int do_rt_sigreturn(struct switch_stack *sw)
{
struct pt_regs *regs = (struct pt_regs *)(sw + 1);
/* Verify, can we follow the stack back */
struct rt_sigframe __user *frame;
sigset_t set;
int rval;
frame = (struct rt_sigframe __user *) regs->sp;
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 (rt_restore_ucontext(regs, sw, &frame->uc, &rval))
goto badframe;
return rval;
badframe:
force_sig(SIGSEGV);
return 0;
}
static inline int rt_setup_ucontext(struct ucontext __user *uc, struct pt_regs *regs)
{
struct switch_stack *sw = (struct switch_stack *)regs - 1;
unsigned long __user *gregs = uc->uc_mcontext.gregs;
int err = 0;
err |= __put_user(MCONTEXT_VERSION, &uc->uc_mcontext.version);
err |= __put_user(regs->r1, &gregs[0]);
err |= __put_user(regs->r2, &gregs[1]);
err |= __put_user(regs->r3, &gregs[2]);
err |= __put_user(regs->r4, &gregs[3]);
err |= __put_user(regs->r5, &gregs[4]);
err |= __put_user(regs->r6, &gregs[5]);
err |= __put_user(regs->r7, &gregs[6]);
err |= __put_user(regs->r8, &gregs[7]);
err |= __put_user(regs->r9, &gregs[8]);
err |= __put_user(regs->r10, &gregs[9]);
err |= __put_user(regs->r11, &gregs[10]);
err |= __put_user(regs->r12, &gregs[11]);
err |= __put_user(regs->r13, &gregs[12]);
err |= __put_user(regs->r14, &gregs[13]);
err |= __put_user(regs->r15, &gregs[14]);
err |= __put_user(sw->r16, &gregs[15]);
err |= __put_user(sw->r17, &gregs[16]);
err |= __put_user(sw->r18, &gregs[17]);
err |= __put_user(sw->r19, &gregs[18]);
err |= __put_user(sw->r20, &gregs[19]);
err |= __put_user(sw->r21, &gregs[20]);
err |= __put_user(sw->r22, &gregs[21]);
err |= __put_user(sw->r23, &gregs[22]);
err |= __put_user(regs->ra, &gregs[23]);
err |= __put_user(sw->fp, &gregs[24]);
err |= __put_user(sw->gp, &gregs[25]);
err |= __put_user(regs->ea, &gregs[27]);
err |= __put_user(regs->sp, &gregs[28]);
return err;
}
static inline void __user *get_sigframe(struct ksignal *ksig,
struct pt_regs *regs,
size_t frame_size)
{
unsigned long usp;
/* Default to using normal stack. */
usp = regs->sp;
/* This is the X/Open sanctioned signal stack switching. */
usp = sigsp(usp, ksig);
/* Verify, is it 32 or 64 bit aligned */
return (void __user *)((usp - frame_size) & -8UL);
}
static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
struct pt_regs *regs)
{
struct rt_sigframe __user *frame;
int err = 0;
frame = get_sigframe(ksig, regs, sizeof(*frame));
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
err |= copy_siginfo_to_user(&frame->info, &ksig->info);
/* Create the ucontext. */
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(0, &frame->uc.uc_link);
err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
err |= rt_setup_ucontext(&frame->uc, regs);
err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
if (err)
goto give_sigsegv;
/* Set up to return from userspace; jump to fixed address sigreturn
trampoline on kuser page. */
regs->ra = (unsigned long) (0x1044);
/* Set up registers for signal handler */
regs->sp = (unsigned long) frame;
regs->r4 = (unsigned long) ksig->sig;
regs->r5 = (unsigned long) &frame->info;
regs->r6 = (unsigned long) &frame->uc;
regs->ea = (unsigned long) ksig->ka.sa.sa_handler;
return 0;
give_sigsegv:
force_sigsegv(ksig->sig);
return -EFAULT;
}
/*
* OK, we're invoking a handler
*/
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
int ret;
sigset_t *oldset = sigmask_to_save();
/* set up the stack frame */
ret = setup_rt_frame(ksig, oldset, regs);
signal_setup_done(ret, ksig, 0);
}
static int do_signal(struct pt_regs *regs)
{
unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
int restart = 0;
struct ksignal ksig;
current->thread.kregs = regs;
/*
* If we were from a system call, check for system call restarting...
*/
if (regs->orig_r2 >= 0) {
continue_addr = regs->ea;
restart_addr = continue_addr - 4;
retval = regs->r2;
/*
* Prepare for system call restart. We do this here so that a
* debugger will see the already changed PC.
*/
switch (retval) {
case ERESTART_RESTARTBLOCK:
restart = -2;
fallthrough;
case ERESTARTNOHAND:
case ERESTARTSYS:
case ERESTARTNOINTR:
restart++;
regs->r2 = regs->orig_r2;
regs->r7 = regs->orig_r7;
regs->ea = restart_addr;
break;
}
}
if (get_signal(&ksig)) {
/* handler */
if (unlikely(restart && regs->ea == restart_addr)) {
if (retval == ERESTARTNOHAND ||
retval == ERESTART_RESTARTBLOCK ||
(retval == ERESTARTSYS
&& !(ksig.ka.sa.sa_flags & SA_RESTART))) {
regs->r2 = EINTR;
regs->r7 = 1;
regs->ea = continue_addr;
}
}
handle_signal(&ksig, regs);
return 0;
}
/*
* No handler present
*/
if (unlikely(restart) && regs->ea == restart_addr) {
regs->ea = continue_addr;
regs->r2 = __NR_restart_syscall;
}
/*
* If there's no signal to deliver, we just put the saved sigmask back.
*/
restore_saved_sigmask();
return restart;
}
asmlinkage int do_notify_resume(struct pt_regs *regs)
{
/*
* We want the common case to go fast, which is why we may in certain
* cases get here from kernel mode. Just return without doing anything
* if so.
*/
if (!user_mode(regs))
return 0;
if (test_thread_flag(TIF_SIGPENDING) ||
test_thread_flag(TIF_NOTIFY_SIGNAL)) {
int restart = do_signal(regs);
if (unlikely(restart)) {
/*
* Restart without handlers.
* Deal with it without leaving
* the kernel space.
*/
return restart;
}
} else if (test_thread_flag(TIF_NOTIFY_RESUME))
tracehook_notify_resume(regs);
return 0;
}
|
