1 /*
2 * linux/arch/x86_64/ia32/ia32_signal.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
6 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
7 * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
8 * 2000-12-* x86-64 compatibility mode signal handling by Andi Kleen
9 */
10
11 #include <linux/sched.h>
12 #include <linux/mm.h>
13 #include <linux/smp.h>
14 #include <linux/kernel.h>
15 #include <linux/errno.h>
16 #include <linux/wait.h>
17 #include <linux/unistd.h>
18 #include <linux/stddef.h>
19 #include <linux/personality.h>
20 #include <linux/compat.h>
21 #include <linux/binfmts.h>
22 #include <asm/ucontext.h>
23 #include <asm/uaccess.h>
24 #include <asm/fpu/internal.h>
25 #include <asm/fpu/signal.h>
26 #include <asm/ptrace.h>
27 #include <asm/ia32_unistd.h>
28 #include <asm/user32.h>
29 #include <uapi/asm/sigcontext.h>
30 #include <asm/proto.h>
31 #include <asm/vdso.h>
32 #include <asm/sigframe.h>
33 #include <asm/sighandling.h>
34 #include <asm/sys_ia32.h>
35 #include <asm/smap.h>
36
37 /*
38 * Do a signal return; undo the signal stack.
39 */
40 #define loadsegment_gs(v) load_gs_index(v)
41 #define loadsegment_fs(v) loadsegment(fs, v)
42 #define loadsegment_ds(v) loadsegment(ds, v)
43 #define loadsegment_es(v) loadsegment(es, v)
44
45 #define get_user_seg(seg) ({ unsigned int v; savesegment(seg, v); v; })
46 #define set_user_seg(seg, v) loadsegment_##seg(v)
47
48 #define COPY(x) { \
49 get_user_ex(regs->x, &sc->x); \
50 }
51
52 #define GET_SEG(seg) ({ \
53 unsigned short tmp; \
54 get_user_ex(tmp, &sc->seg); \
55 tmp; \
56 })
57
58 #define COPY_SEG_CPL3(seg) do { \
59 regs->seg = GET_SEG(seg) | 3; \
60 } while (0)
61
62 #define RELOAD_SEG(seg) { \
63 unsigned int pre = GET_SEG(seg); \
64 unsigned int cur = get_user_seg(seg); \
65 pre |= 3; \
66 if (pre != cur) \
67 set_user_seg(seg, pre); \
68 }
69
ia32_restore_sigcontext(struct pt_regs * regs,struct sigcontext_32 __user * sc)70 static int ia32_restore_sigcontext(struct pt_regs *regs,
71 struct sigcontext_32 __user *sc)
72 {
73 unsigned int tmpflags, err = 0;
74 void __user *buf;
75 u32 tmp;
76
77 /* Always make any pending restarted system calls return -EINTR */
78 current->restart_block.fn = do_no_restart_syscall;
79
80 get_user_try {
81 /*
82 * Reload fs and gs if they have changed in the signal
83 * handler. This does not handle long fs/gs base changes in
84 * the handler, but does not clobber them at least in the
85 * normal case.
86 */
87 RELOAD_SEG(gs);
88 RELOAD_SEG(fs);
89 RELOAD_SEG(ds);
90 RELOAD_SEG(es);
91
92 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
93 COPY(dx); COPY(cx); COPY(ip); COPY(ax);
94 /* Don't touch extended registers */
95
96 COPY_SEG_CPL3(cs);
97 COPY_SEG_CPL3(ss);
98
99 get_user_ex(tmpflags, &sc->flags);
100 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
101 /* disable syscall checks */
102 regs->orig_ax = -1;
103
104 get_user_ex(tmp, &sc->fpstate);
105 buf = compat_ptr(tmp);
106 } get_user_catch(err);
107
108 err |= fpu__restore_sig(buf, 1);
109
110 force_iret();
111
112 return err;
113 }
114
sys32_sigreturn(void)115 asmlinkage long sys32_sigreturn(void)
116 {
117 struct pt_regs *regs = current_pt_regs();
118 struct sigframe_ia32 __user *frame = (struct sigframe_ia32 __user *)(regs->sp-8);
119 sigset_t set;
120
121 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
122 goto badframe;
123 if (__get_user(set.sig[0], &frame->sc.oldmask)
124 || (_COMPAT_NSIG_WORDS > 1
125 && __copy_from_user((((char *) &set.sig) + 4),
126 &frame->extramask,
127 sizeof(frame->extramask))))
128 goto badframe;
129
130 set_current_blocked(&set);
131
132 if (ia32_restore_sigcontext(regs, &frame->sc))
133 goto badframe;
134 return regs->ax;
135
136 badframe:
137 signal_fault(regs, frame, "32bit sigreturn");
138 return 0;
139 }
140
sys32_rt_sigreturn(void)141 asmlinkage long sys32_rt_sigreturn(void)
142 {
143 struct pt_regs *regs = current_pt_regs();
144 struct rt_sigframe_ia32 __user *frame;
145 sigset_t set;
146
147 frame = (struct rt_sigframe_ia32 __user *)(regs->sp - 4);
148
149 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
150 goto badframe;
151 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
152 goto badframe;
153
154 set_current_blocked(&set);
155
156 if (ia32_restore_sigcontext(regs, &frame->uc.uc_mcontext))
157 goto badframe;
158
159 if (compat_restore_altstack(&frame->uc.uc_stack))
160 goto badframe;
161
162 return regs->ax;
163
164 badframe:
165 signal_fault(regs, frame, "32bit rt sigreturn");
166 return 0;
167 }
168
169 /*
170 * Set up a signal frame.
171 */
172
ia32_setup_sigcontext(struct sigcontext_32 __user * sc,void __user * fpstate,struct pt_regs * regs,unsigned int mask)173 static int ia32_setup_sigcontext(struct sigcontext_32 __user *sc,
174 void __user *fpstate,
175 struct pt_regs *regs, unsigned int mask)
176 {
177 int err = 0;
178
179 put_user_try {
180 put_user_ex(get_user_seg(gs), (unsigned int __user *)&sc->gs);
181 put_user_ex(get_user_seg(fs), (unsigned int __user *)&sc->fs);
182 put_user_ex(get_user_seg(ds), (unsigned int __user *)&sc->ds);
183 put_user_ex(get_user_seg(es), (unsigned int __user *)&sc->es);
184
185 put_user_ex(regs->di, &sc->di);
186 put_user_ex(regs->si, &sc->si);
187 put_user_ex(regs->bp, &sc->bp);
188 put_user_ex(regs->sp, &sc->sp);
189 put_user_ex(regs->bx, &sc->bx);
190 put_user_ex(regs->dx, &sc->dx);
191 put_user_ex(regs->cx, &sc->cx);
192 put_user_ex(regs->ax, &sc->ax);
193 put_user_ex(current->thread.trap_nr, &sc->trapno);
194 put_user_ex(current->thread.error_code, &sc->err);
195 put_user_ex(regs->ip, &sc->ip);
196 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
197 put_user_ex(regs->flags, &sc->flags);
198 put_user_ex(regs->sp, &sc->sp_at_signal);
199 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
200
201 put_user_ex(ptr_to_compat(fpstate), &sc->fpstate);
202
203 /* non-iBCS2 extensions.. */
204 put_user_ex(mask, &sc->oldmask);
205 put_user_ex(current->thread.cr2, &sc->cr2);
206 } put_user_catch(err);
207
208 return err;
209 }
210
211 /*
212 * Determine which stack to use..
213 */
get_sigframe(struct ksignal * ksig,struct pt_regs * regs,size_t frame_size,void __user ** fpstate)214 static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
215 size_t frame_size,
216 void __user **fpstate)
217 {
218 struct fpu *fpu = ¤t->thread.fpu;
219 unsigned long sp;
220
221 /* Default to using normal stack */
222 sp = regs->sp;
223
224 /* This is the X/Open sanctioned signal stack switching. */
225 if (ksig->ka.sa.sa_flags & SA_ONSTACK)
226 sp = sigsp(sp, ksig);
227 /* This is the legacy signal stack switching. */
228 else if ((regs->ss & 0xffff) != __USER32_DS &&
229 !(ksig->ka.sa.sa_flags & SA_RESTORER) &&
230 ksig->ka.sa.sa_restorer)
231 sp = (unsigned long) ksig->ka.sa.sa_restorer;
232
233 if (fpu->fpstate_active) {
234 unsigned long fx_aligned, math_size;
235
236 sp = fpu__alloc_mathframe(sp, 1, &fx_aligned, &math_size);
237 *fpstate = (struct _fpstate_32 __user *) sp;
238 if (copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned,
239 math_size) < 0)
240 return (void __user *) -1L;
241 }
242
243 sp -= frame_size;
244 /* Align the stack pointer according to the i386 ABI,
245 * i.e. so that on function entry ((sp + 4) & 15) == 0. */
246 sp = ((sp + 4) & -16ul) - 4;
247 return (void __user *) sp;
248 }
249
ia32_setup_frame(int sig,struct ksignal * ksig,compat_sigset_t * set,struct pt_regs * regs)250 int ia32_setup_frame(int sig, struct ksignal *ksig,
251 compat_sigset_t *set, struct pt_regs *regs)
252 {
253 struct sigframe_ia32 __user *frame;
254 void __user *restorer;
255 int err = 0;
256 void __user *fpstate = NULL;
257
258 /* copy_to_user optimizes that into a single 8 byte store */
259 static const struct {
260 u16 poplmovl;
261 u32 val;
262 u16 int80;
263 } __attribute__((packed)) code = {
264 0xb858, /* popl %eax ; movl $...,%eax */
265 __NR_ia32_sigreturn,
266 0x80cd, /* int $0x80 */
267 };
268
269 frame = get_sigframe(ksig, regs, sizeof(*frame), &fpstate);
270
271 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
272 return -EFAULT;
273
274 if (__put_user(sig, &frame->sig))
275 return -EFAULT;
276
277 if (ia32_setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
278 return -EFAULT;
279
280 if (_COMPAT_NSIG_WORDS > 1) {
281 if (__copy_to_user(frame->extramask, &set->sig[1],
282 sizeof(frame->extramask)))
283 return -EFAULT;
284 }
285
286 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
287 restorer = ksig->ka.sa.sa_restorer;
288 } else {
289 /* Return stub is in 32bit vsyscall page */
290 if (current->mm->context.vdso)
291 restorer = current->mm->context.vdso +
292 vdso_image_32.sym___kernel_sigreturn;
293 else
294 restorer = &frame->retcode;
295 }
296
297 put_user_try {
298 put_user_ex(ptr_to_compat(restorer), &frame->pretcode);
299
300 /*
301 * These are actually not used anymore, but left because some
302 * gdb versions depend on them as a marker.
303 */
304 put_user_ex(*((u64 *)&code), (u64 __user *)frame->retcode);
305 } put_user_catch(err);
306
307 if (err)
308 return -EFAULT;
309
310 /* Set up registers for signal handler */
311 regs->sp = (unsigned long) frame;
312 regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
313
314 /* Make -mregparm=3 work */
315 regs->ax = sig;
316 regs->dx = 0;
317 regs->cx = 0;
318
319 loadsegment(ds, __USER32_DS);
320 loadsegment(es, __USER32_DS);
321
322 regs->cs = __USER32_CS;
323 regs->ss = __USER32_DS;
324
325 return 0;
326 }
327
ia32_setup_rt_frame(int sig,struct ksignal * ksig,compat_sigset_t * set,struct pt_regs * regs)328 int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
329 compat_sigset_t *set, struct pt_regs *regs)
330 {
331 struct rt_sigframe_ia32 __user *frame;
332 void __user *restorer;
333 int err = 0;
334 void __user *fpstate = NULL;
335
336 /* __copy_to_user optimizes that into a single 8 byte store */
337 static const struct {
338 u8 movl;
339 u32 val;
340 u16 int80;
341 u8 pad;
342 } __attribute__((packed)) code = {
343 0xb8,
344 __NR_ia32_rt_sigreturn,
345 0x80cd,
346 0,
347 };
348
349 frame = get_sigframe(ksig, regs, sizeof(*frame), &fpstate);
350
351 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
352 return -EFAULT;
353
354 put_user_try {
355 put_user_ex(sig, &frame->sig);
356 put_user_ex(ptr_to_compat(&frame->info), &frame->pinfo);
357 put_user_ex(ptr_to_compat(&frame->uc), &frame->puc);
358
359 /* Create the ucontext. */
360 if (cpu_has_xsave)
361 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
362 else
363 put_user_ex(0, &frame->uc.uc_flags);
364 put_user_ex(0, &frame->uc.uc_link);
365 compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
366
367 if (ksig->ka.sa.sa_flags & SA_RESTORER)
368 restorer = ksig->ka.sa.sa_restorer;
369 else
370 restorer = current->mm->context.vdso +
371 vdso_image_32.sym___kernel_rt_sigreturn;
372 put_user_ex(ptr_to_compat(restorer), &frame->pretcode);
373
374 /*
375 * Not actually used anymore, but left because some gdb
376 * versions need it.
377 */
378 put_user_ex(*((u64 *)&code), (u64 __user *)frame->retcode);
379 } put_user_catch(err);
380
381 err |= copy_siginfo_to_user32(&frame->info, &ksig->info);
382 err |= ia32_setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
383 regs, set->sig[0]);
384 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
385
386 if (err)
387 return -EFAULT;
388
389 /* Set up registers for signal handler */
390 regs->sp = (unsigned long) frame;
391 regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
392
393 /* Make -mregparm=3 work */
394 regs->ax = sig;
395 regs->dx = (unsigned long) &frame->info;
396 regs->cx = (unsigned long) &frame->uc;
397
398 loadsegment(ds, __USER32_DS);
399 loadsegment(es, __USER32_DS);
400
401 regs->cs = __USER32_CS;
402 regs->ss = __USER32_DS;
403
404 return 0;
405 }
406