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
|
/*
* Copyright 2004-2010 Analog Devices Inc.
*
* Licensed under the GPL-2 or later
*/
#include <linux/signal.h>
#include <linux/syscalls.h>
#include <linux/ptrace.h>
#include <linux/tty.h>
#include <linux/personality.h>
#include <linux/binfmts.h>
#include <linux/freezer.h>
#include <linux/uaccess.h>
#include <linux/tracehook.h>
#include <asm/cacheflush.h>
#include <asm/ucontext.h>
#include <asm/fixed_code.h>
#include <asm/syscall.h>
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
/* Location of the trace bit in SYSCFG. */
#define TRACE_BITS 0x0001
struct fdpic_func_descriptor {
unsigned long text;
unsigned long GOT;
};
struct rt_sigframe {
int sig;
struct siginfo *pinfo;
void *puc;
/* This is no longer needed by the kernel, but unfortunately userspace
* code expects it to be there. */
char retcode[8];
struct siginfo info;
struct ucontext uc;
};
asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
{
return do_sigaltstack(uss, uoss, rdusp());
}
static inline int
rt_restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *pr0)
{
unsigned long usp = 0;
int err = 0;
/* Always make any pending restarted system calls return -EINTR */
current_thread_info()->restart_block.fn = do_no_restart_syscall;
#define RESTORE(x) err |= __get_user(regs->x, &sc->sc_##x)
/* restore passed registers */
RESTORE(r0); RESTORE(r1); RESTORE(r2); RESTORE(r3);
RESTORE(r4); RESTORE(r5); RESTORE(r6); RESTORE(r7);
RESTORE(p0); RESTORE(p1); RESTORE(p2); RESTORE(p3);
RESTORE(p4); RESTORE(p5);
err |= __get_user(usp, &sc->sc_usp);
wrusp(usp);
RESTORE(a0w); RESTORE(a1w);
RESTORE(a0x); RESTORE(a1x);
RESTORE(astat);
RESTORE(rets);
RESTORE(pc);
RESTORE(retx);
RESTORE(fp);
RESTORE(i0); RESTORE(i1); RESTORE(i2); RESTORE(i3);
RESTORE(m0); RESTORE(m1); RESTORE(m2); RESTORE(m3);
RESTORE(l0); RESTORE(l1); RESTORE(l2); RESTORE(l3);
RESTORE(b0); RESTORE(b1); RESTORE(b2); RESTORE(b3);
RESTORE(lc0); RESTORE(lc1);
RESTORE(lt0); RESTORE(lt1);
RESTORE(lb0); RESTORE(lb1);
RESTORE(seqstat);
regs->orig_p0 = -1; /* disable syscall checks */
*pr0 = regs->r0;
return err;
}
asmlinkage int do_rt_sigreturn(unsigned long __unused)
{
struct pt_regs *regs = (struct pt_regs *)__unused;
unsigned long usp = rdusp();
struct rt_sigframe *frame = (struct rt_sigframe *)(usp);
sigset_t set;
int r0;
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
goto badframe;
sigdelsetmask(&set, ~_BLOCKABLE);
set_current_blocked(&set);
if (rt_restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
goto badframe;
if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->usp) == -EFAULT)
goto badframe;
return r0;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
static inline int rt_setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs)
{
int err = 0;
#define SETUP(x) err |= __put_user(regs->x, &sc->sc_##x)
SETUP(r0); SETUP(r1); SETUP(r2); SETUP(r3);
SETUP(r4); SETUP(r5); SETUP(r6); SETUP(r7);
SETUP(p0); SETUP(p1); SETUP(p2); SETUP(p3);
SETUP(p4); SETUP(p5);
err |= __put_user(rdusp(), &sc->sc_usp);
SETUP(a0w); SETUP(a1w);
SETUP(a0x); SETUP(a1x);
SETUP(astat);
SETUP(rets);
SETUP(pc);
SETUP(retx);
SETUP(fp);
SETUP(i0); SETUP(i1); SETUP(i2); SETUP(i3);
SETUP(m0); SETUP(m1); SETUP(m2); SETUP(m3);
SETUP(l0); SETUP(l1); SETUP(l2); SETUP(l3);
SETUP(b0); SETUP(b1); SETUP(b2); SETUP(b3);
SETUP(lc0); SETUP(lc1);
SETUP(lt0); SETUP(lt1);
SETUP(lb0); SETUP(lb1);
SETUP(seqstat);
return err;
}
static inline void *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
size_t frame_size)
{
unsigned long usp;
/* Default to using normal stack. */
usp = rdusp();
/* This is the X/Open sanctioned signal stack switching. */
if (ka->sa.sa_flags & SA_ONSTACK) {
if (!on_sig_stack(usp))
usp = current->sas_ss_sp + current->sas_ss_size;
}
return (void *)((usp - frame_size) & -8UL);
}
static int
setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t * info,
sigset_t * set, struct pt_regs *regs)
{
struct rt_sigframe *frame;
int err = 0;
frame = get_sigframe(ka, regs, sizeof(*frame));
err |= __put_user((current_thread_info()->exec_domain
&& current_thread_info()->exec_domain->signal_invmap
&& sig < 32
? current_thread_info()->exec_domain->
signal_invmap[sig] : sig), &frame->sig);
err |= __put_user(&frame->info, &frame->pinfo);
err |= __put_user(&frame->uc, &frame->puc);
err |= copy_siginfo_to_user(&frame->info, info);
/* Create the ucontext. */
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(0, &frame->uc.uc_link);
err |=
__put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
err |= __put_user(sas_ss_flags(rdusp()), &frame->uc.uc_stack.ss_flags);
err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
err |= rt_setup_sigcontext(&frame->uc.uc_mcontext, regs);
err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
if (err)
goto give_sigsegv;
/* Set up registers for signal handler */
wrusp((unsigned long)frame);
if (current->personality & FDPIC_FUNCPTRS) {
struct fdpic_func_descriptor __user *funcptr =
(struct fdpic_func_descriptor *) ka->sa.sa_handler;
__get_user(regs->pc, &funcptr->text);
__get_user(regs->p3, &funcptr->GOT);
} else
regs->pc = (unsigned long)ka->sa.sa_handler;
regs->rets = SIGRETURN_STUB;
regs->r0 = frame->sig;
regs->r1 = (unsigned long)(&frame->info);
regs->r2 = (unsigned long)(&frame->uc);
return 0;
give_sigsegv:
force_sigsegv(sig, current);
return -EFAULT;
}
static inline void
handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
{
switch (regs->r0) {
case -ERESTARTNOHAND:
if (!has_handler)
goto do_restart;
regs->r0 = -EINTR;
break;
case -ERESTARTSYS:
if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
regs->r0 = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
do_restart:
regs->p0 = regs->orig_p0;
regs->r0 = regs->orig_r0;
regs->pc -= 2;
break;
case -ERESTART_RESTARTBLOCK:
regs->p0 = __NR_restart_syscall;
regs->pc -= 2;
break;
}
}
/*
* OK, we're invoking a handler
*/
static void
handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka,
struct pt_regs *regs)
{
int ret;
/* are we from a system call? to see pt_regs->orig_p0 */
if (regs->orig_p0 >= 0)
/* If so, check system call restarting.. */
handle_restart(regs, ka, 1);
/* set up the stack frame */
ret = setup_rt_frame(sig, ka, info, sigmask_to_save(), regs);
if (ret)
return;
block_sigmask(ka, sig);
tracehook_signal_handler(sig, info, ka, regs,
test_thread_flag(TIF_SINGLESTEP));
}
/*
* Note that 'init' is a special process: it doesn't get signals it doesn't
* want to handle. Thus you cannot kill init even with a SIGKILL even by
* mistake.
*
* Note that we go through the signals twice: once to check the signals
* that the kernel can handle, and then we build all the user-level signal
* handling stack-frames in one go after that.
*/
asmlinkage void do_signal(struct pt_regs *regs)
{
siginfo_t info;
int signr;
struct k_sigaction ka;
current->thread.esp0 = (unsigned long)regs;
signr = get_signal_to_deliver(&info, &ka, regs, NULL);
if (signr > 0) {
/* Whee! Actually deliver the signal. */
handle_signal(signr, &info, &ka, regs);
return;
}
/* Did we come from a system call? */
if (regs->orig_p0 >= 0)
/* Restart the system call - no handlers present */
handle_restart(regs, NULL, 0);
/* if there's no signal to deliver, we just put the saved sigmask
* back */
restore_saved_sigmask();
}
/*
* notification of userspace execution resumption
*/
asmlinkage void do_notify_resume(struct pt_regs *regs)
{
if (test_thread_flag(TIF_SIGPENDING))
do_signal(regs);
if (test_thread_flag(TIF_NOTIFY_RESUME)) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
}
|
