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1da177e4 | 1 | /* |
1da177e4 LT |
2 | * PowerPC version |
3 | * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) | |
4 | * | |
5 | * Derived from "arch/i386/kernel/signal.c" | |
6 | * Copyright (C) 1991, 1992 Linus Torvalds | |
7 | * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU General Public License | |
11 | * as published by the Free Software Foundation; either version | |
12 | * 2 of the License, or (at your option) any later version. | |
13 | */ | |
14 | ||
1da177e4 LT |
15 | #include <linux/sched.h> |
16 | #include <linux/mm.h> | |
17 | #include <linux/smp.h> | |
1da177e4 LT |
18 | #include <linux/kernel.h> |
19 | #include <linux/signal.h> | |
20 | #include <linux/errno.h> | |
21 | #include <linux/wait.h> | |
22 | #include <linux/unistd.h> | |
23 | #include <linux/stddef.h> | |
24 | #include <linux/elf.h> | |
25 | #include <linux/ptrace.h> | |
26 | #include <linux/module.h> | |
27 | ||
28 | #include <asm/sigcontext.h> | |
29 | #include <asm/ucontext.h> | |
30 | #include <asm/uaccess.h> | |
31 | #include <asm/pgtable.h> | |
1da177e4 LT |
32 | #include <asm/unistd.h> |
33 | #include <asm/cacheflush.h> | |
a7f31841 | 34 | #include <asm/syscalls.h> |
1da177e4 LT |
35 | #include <asm/vdso.h> |
36 | ||
22e38f29 | 37 | #include "signal.h" |
1da177e4 | 38 | |
1da177e4 | 39 | #define DEBUG_SIG 0 |
1da177e4 | 40 | |
6741f3a7 | 41 | #define GP_REGS_SIZE min(sizeof(elf_gregset_t), sizeof(struct pt_regs)) |
1da177e4 LT |
42 | #define FP_REGS_SIZE sizeof(elf_fpregset_t) |
43 | ||
44 | #define TRAMP_TRACEBACK 3 | |
45 | #define TRAMP_SIZE 6 | |
46 | ||
47 | /* | |
48 | * When we have signals to deliver, we set up on the user stack, | |
49 | * going down from the original stack pointer: | |
50 | * 1) a rt_sigframe struct which contains the ucontext | |
51 | * 2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller | |
52 | * frame for the signal handler. | |
53 | */ | |
54 | ||
55 | struct rt_sigframe { | |
56 | /* sys_rt_sigreturn requires the ucontext be the first field */ | |
57 | struct ucontext uc; | |
58 | unsigned long _unused[2]; | |
59 | unsigned int tramp[TRAMP_SIZE]; | |
29e646df AV |
60 | struct siginfo __user *pinfo; |
61 | void __user *puc; | |
1da177e4 LT |
62 | struct siginfo info; |
63 | /* 64 bit ABI allows for 288 bytes below sp before decrementing it. */ | |
64 | char abigap[288]; | |
65 | } __attribute__ ((aligned (16))); | |
66 | ||
d0c3d534 OJ |
67 | static const char fmt32[] = KERN_INFO \ |
68 | "%s[%d]: bad frame in %s: %08lx nip %08lx lr %08lx\n"; | |
69 | static const char fmt64[] = KERN_INFO \ | |
70 | "%s[%d]: bad frame in %s: %016lx nip %016lx lr %016lx\n"; | |
71 | ||
1da177e4 LT |
72 | /* |
73 | * Set up the sigcontext for the signal frame. | |
74 | */ | |
75 | ||
76 | static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, | |
77 | int signr, sigset_t *set, unsigned long handler) | |
78 | { | |
79 | /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the | |
80 | * process never used altivec yet (MSR_VEC is zero in pt_regs of | |
81 | * the context). This is very important because we must ensure we | |
82 | * don't lose the VRSAVE content that may have been set prior to | |
83 | * the process doing its first vector operation | |
84 | * Userland shall check AT_HWCAP to know wether it can rely on the | |
85 | * v_regs pointer or not | |
86 | */ | |
87 | #ifdef CONFIG_ALTIVEC | |
88 | elf_vrreg_t __user *v_regs = (elf_vrreg_t __user *)(((unsigned long)sc->vmx_reserve + 15) & ~0xful); | |
89 | #endif | |
0be234a4 | 90 | unsigned long msr = regs->msr; |
1da177e4 LT |
91 | long err = 0; |
92 | ||
93 | flush_fp_to_thread(current); | |
94 | ||
1da177e4 LT |
95 | #ifdef CONFIG_ALTIVEC |
96 | err |= __put_user(v_regs, &sc->v_regs); | |
97 | ||
98 | /* save altivec registers */ | |
99 | if (current->thread.used_vr) { | |
100 | flush_altivec_to_thread(current); | |
101 | /* Copy 33 vec registers (vr0..31 and vscr) to the stack */ | |
102 | err |= __copy_to_user(v_regs, current->thread.vr, 33 * sizeof(vector128)); | |
103 | /* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg) | |
104 | * contains valid data. | |
105 | */ | |
0be234a4 | 106 | msr |= MSR_VEC; |
1da177e4 LT |
107 | } |
108 | /* We always copy to/from vrsave, it's 0 if we don't have or don't | |
109 | * use altivec. | |
110 | */ | |
111 | err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]); | |
112 | #else /* CONFIG_ALTIVEC */ | |
113 | err |= __put_user(0, &sc->v_regs); | |
114 | #endif /* CONFIG_ALTIVEC */ | |
115 | err |= __put_user(&sc->gp_regs, &sc->regs); | |
1bd79336 | 116 | WARN_ON(!FULL_REGS(regs)); |
1da177e4 | 117 | err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE); |
0be234a4 | 118 | err |= __put_user(msr, &sc->gp_regs[PT_MSR]); |
1da177e4 LT |
119 | err |= __copy_to_user(&sc->fp_regs, ¤t->thread.fpr, FP_REGS_SIZE); |
120 | err |= __put_user(signr, &sc->signal); | |
121 | err |= __put_user(handler, &sc->handler); | |
122 | if (set != NULL) | |
123 | err |= __put_user(set->sig[0], &sc->oldmask); | |
124 | ||
125 | return err; | |
126 | } | |
127 | ||
128 | /* | |
129 | * Restore the sigcontext from the signal frame. | |
130 | */ | |
131 | ||
132 | static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig, | |
133 | struct sigcontext __user *sc) | |
134 | { | |
135 | #ifdef CONFIG_ALTIVEC | |
136 | elf_vrreg_t __user *v_regs; | |
137 | #endif | |
138 | unsigned long err = 0; | |
139 | unsigned long save_r13 = 0; | |
140 | elf_greg_t *gregs = (elf_greg_t *)regs; | |
1da177e4 | 141 | unsigned long msr; |
1da177e4 LT |
142 | int i; |
143 | ||
144 | /* If this is not a signal return, we preserve the TLS in r13 */ | |
145 | if (!sig) | |
146 | save_r13 = regs->gpr[13]; | |
147 | ||
148 | /* copy everything before MSR */ | |
149 | err |= __copy_from_user(regs, &sc->gp_regs, | |
150 | PT_MSR*sizeof(unsigned long)); | |
151 | ||
fab5db97 PM |
152 | /* get MSR separately, transfer the LE bit if doing signal return */ |
153 | err |= __get_user(msr, &sc->gp_regs[PT_MSR]); | |
154 | if (sig) | |
155 | regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE); | |
156 | ||
157 | /* skip SOFTE */ | |
1da177e4 LT |
158 | for (i = PT_MSR+1; i <= PT_RESULT; i++) { |
159 | if (i == PT_SOFTE) | |
160 | continue; | |
161 | err |= __get_user(gregs[i], &sc->gp_regs[i]); | |
162 | } | |
163 | ||
164 | if (!sig) | |
165 | regs->gpr[13] = save_r13; | |
1da177e4 LT |
166 | if (set != NULL) |
167 | err |= __get_user(set->sig[0], &sc->oldmask); | |
168 | ||
5388fb10 PM |
169 | /* |
170 | * Do this before updating the thread state in | |
171 | * current->thread.fpr/vr. That way, if we get preempted | |
172 | * and another task grabs the FPU/Altivec, it won't be | |
173 | * tempted to save the current CPU state into the thread_struct | |
174 | * and corrupt what we are writing there. | |
175 | */ | |
176 | discard_lazy_cpu_state(); | |
177 | ||
ae62fbb5 PM |
178 | /* |
179 | * Force reload of FP/VEC. | |
180 | * This has to be done before copying stuff into current->thread.fpr/vr | |
181 | * for the reasons explained in the previous comment. | |
182 | */ | |
183 | regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC); | |
184 | ||
5388fb10 PM |
185 | err |= __copy_from_user(¤t->thread.fpr, &sc->fp_regs, FP_REGS_SIZE); |
186 | ||
1da177e4 LT |
187 | #ifdef CONFIG_ALTIVEC |
188 | err |= __get_user(v_regs, &sc->v_regs); | |
1da177e4 LT |
189 | if (err) |
190 | return err; | |
7c85d1f9 PM |
191 | if (v_regs && !access_ok(VERIFY_READ, v_regs, 34 * sizeof(vector128))) |
192 | return -EFAULT; | |
1da177e4 LT |
193 | /* Copy 33 vec registers (vr0..31 and vscr) from the stack */ |
194 | if (v_regs != 0 && (msr & MSR_VEC) != 0) | |
195 | err |= __copy_from_user(current->thread.vr, v_regs, | |
196 | 33 * sizeof(vector128)); | |
197 | else if (current->thread.used_vr) | |
198 | memset(current->thread.vr, 0, 33 * sizeof(vector128)); | |
199 | /* Always get VRSAVE back */ | |
200 | if (v_regs != 0) | |
201 | err |= __get_user(current->thread.vrsave, (u32 __user *)&v_regs[33]); | |
202 | else | |
203 | current->thread.vrsave = 0; | |
204 | #endif /* CONFIG_ALTIVEC */ | |
205 | ||
1da177e4 LT |
206 | return err; |
207 | } | |
208 | ||
1da177e4 LT |
209 | /* |
210 | * Setup the trampoline code on the stack | |
211 | */ | |
212 | static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp) | |
213 | { | |
214 | int i; | |
215 | long err = 0; | |
216 | ||
217 | /* addi r1, r1, __SIGNAL_FRAMESIZE # Pop the dummy stackframe */ | |
218 | err |= __put_user(0x38210000UL | (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]); | |
219 | /* li r0, __NR_[rt_]sigreturn| */ | |
220 | err |= __put_user(0x38000000UL | (syscall & 0xffff), &tramp[1]); | |
221 | /* sc */ | |
222 | err |= __put_user(0x44000002UL, &tramp[2]); | |
223 | ||
224 | /* Minimal traceback info */ | |
225 | for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++) | |
226 | err |= __put_user(0, &tramp[i]); | |
227 | ||
228 | if (!err) | |
229 | flush_icache_range((unsigned long) &tramp[0], | |
230 | (unsigned long) &tramp[TRAMP_SIZE]); | |
231 | ||
232 | return err; | |
233 | } | |
234 | ||
1da177e4 LT |
235 | /* |
236 | * Handle {get,set,swap}_context operations | |
237 | */ | |
238 | int sys_swapcontext(struct ucontext __user *old_ctx, | |
239 | struct ucontext __user *new_ctx, | |
240 | long ctx_size, long r6, long r7, long r8, struct pt_regs *regs) | |
241 | { | |
242 | unsigned char tmp; | |
243 | sigset_t set; | |
244 | ||
245 | /* Context size is for future use. Right now, we only make sure | |
246 | * we are passed something we understand | |
247 | */ | |
248 | if (ctx_size < sizeof(struct ucontext)) | |
249 | return -EINVAL; | |
250 | ||
251 | if (old_ctx != NULL) { | |
252 | if (!access_ok(VERIFY_WRITE, old_ctx, sizeof(*old_ctx)) | |
253 | || setup_sigcontext(&old_ctx->uc_mcontext, regs, 0, NULL, 0) | |
254 | || __copy_to_user(&old_ctx->uc_sigmask, | |
255 | ¤t->blocked, sizeof(sigset_t))) | |
256 | return -EFAULT; | |
257 | } | |
258 | if (new_ctx == NULL) | |
259 | return 0; | |
260 | if (!access_ok(VERIFY_READ, new_ctx, sizeof(*new_ctx)) | |
261 | || __get_user(tmp, (u8 __user *) new_ctx) | |
262 | || __get_user(tmp, (u8 __user *) (new_ctx + 1) - 1)) | |
263 | return -EFAULT; | |
264 | ||
265 | /* | |
266 | * If we get a fault copying the context into the kernel's | |
267 | * image of the user's registers, we can't just return -EFAULT | |
268 | * because the user's registers will be corrupted. For instance | |
269 | * the NIP value may have been updated but not some of the | |
270 | * other registers. Given that we have done the access_ok | |
271 | * and successfully read the first and last bytes of the region | |
272 | * above, this should only happen in an out-of-memory situation | |
273 | * or if another thread unmaps the region containing the context. | |
274 | * We kill the task with a SIGSEGV in this situation. | |
275 | */ | |
276 | ||
277 | if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set))) | |
278 | do_exit(SIGSEGV); | |
279 | restore_sigmask(&set); | |
280 | if (restore_sigcontext(regs, NULL, 0, &new_ctx->uc_mcontext)) | |
281 | do_exit(SIGSEGV); | |
282 | ||
283 | /* This returns like rt_sigreturn */ | |
401d1f02 | 284 | set_thread_flag(TIF_RESTOREALL); |
1da177e4 LT |
285 | return 0; |
286 | } | |
287 | ||
288 | ||
289 | /* | |
290 | * Do a signal return; undo the signal stack. | |
291 | */ | |
292 | ||
293 | int sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5, | |
294 | unsigned long r6, unsigned long r7, unsigned long r8, | |
295 | struct pt_regs *regs) | |
296 | { | |
297 | struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1]; | |
298 | sigset_t set; | |
299 | ||
300 | /* Always make any pending restarted system calls return -EINTR */ | |
301 | current_thread_info()->restart_block.fn = do_no_restart_syscall; | |
302 | ||
303 | if (!access_ok(VERIFY_READ, uc, sizeof(*uc))) | |
304 | goto badframe; | |
305 | ||
306 | if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set))) | |
307 | goto badframe; | |
308 | restore_sigmask(&set); | |
309 | if (restore_sigcontext(regs, NULL, 1, &uc->uc_mcontext)) | |
310 | goto badframe; | |
311 | ||
312 | /* do_sigaltstack expects a __user pointer and won't modify | |
313 | * what's in there anyway | |
314 | */ | |
315 | do_sigaltstack(&uc->uc_stack, NULL, regs->gpr[1]); | |
316 | ||
401d1f02 DW |
317 | set_thread_flag(TIF_RESTOREALL); |
318 | return 0; | |
1da177e4 LT |
319 | |
320 | badframe: | |
321 | #if DEBUG_SIG | |
322 | printk("badframe in sys_rt_sigreturn, regs=%p uc=%p &uc->uc_mcontext=%p\n", | |
323 | regs, uc, &uc->uc_mcontext); | |
324 | #endif | |
d0c3d534 OJ |
325 | if (show_unhandled_signals && printk_ratelimit()) |
326 | printk(regs->msr & MSR_SF ? fmt64 : fmt32, | |
327 | current->comm, current->pid, "rt_sigreturn", | |
328 | (long)uc, regs->nip, regs->link); | |
329 | ||
1da177e4 LT |
330 | force_sig(SIGSEGV, current); |
331 | return 0; | |
332 | } | |
333 | ||
f478f543 | 334 | int handle_rt_signal64(int signr, struct k_sigaction *ka, siginfo_t *info, |
1da177e4 LT |
335 | sigset_t *set, struct pt_regs *regs) |
336 | { | |
337 | /* Handler is *really* a pointer to the function descriptor for | |
338 | * the signal routine. The first entry in the function | |
339 | * descriptor is the entry address of signal and the second | |
340 | * entry is the TOC value we need to use. | |
341 | */ | |
342 | func_descr_t __user *funct_desc_ptr; | |
343 | struct rt_sigframe __user *frame; | |
344 | unsigned long newsp = 0; | |
345 | long err = 0; | |
346 | ||
347 | frame = get_sigframe(ka, regs, sizeof(*frame)); | |
a3f61dc0 | 348 | if (unlikely(frame == NULL)) |
1da177e4 LT |
349 | goto badframe; |
350 | ||
351 | err |= __put_user(&frame->info, &frame->pinfo); | |
352 | err |= __put_user(&frame->uc, &frame->puc); | |
353 | err |= copy_siginfo_to_user(&frame->info, info); | |
354 | if (err) | |
355 | goto badframe; | |
356 | ||
357 | /* Create the ucontext. */ | |
358 | err |= __put_user(0, &frame->uc.uc_flags); | |
359 | err |= __put_user(0, &frame->uc.uc_link); | |
360 | err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp); | |
361 | err |= __put_user(sas_ss_flags(regs->gpr[1]), | |
362 | &frame->uc.uc_stack.ss_flags); | |
363 | err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); | |
364 | err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, signr, NULL, | |
365 | (unsigned long)ka->sa.sa_handler); | |
366 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
367 | if (err) | |
368 | goto badframe; | |
369 | ||
cc657f53 PM |
370 | /* Make sure signal handler doesn't get spurious FP exceptions */ |
371 | current->thread.fpscr.val = 0; | |
372 | ||
1da177e4 | 373 | /* Set up to return from userspace. */ |
a5bba930 BH |
374 | if (vdso64_rt_sigtramp && current->mm->context.vdso_base) { |
375 | regs->link = current->mm->context.vdso_base + vdso64_rt_sigtramp; | |
1da177e4 LT |
376 | } else { |
377 | err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]); | |
378 | if (err) | |
379 | goto badframe; | |
380 | regs->link = (unsigned long) &frame->tramp[0]; | |
381 | } | |
382 | funct_desc_ptr = (func_descr_t __user *) ka->sa.sa_handler; | |
383 | ||
384 | /* Allocate a dummy caller frame for the signal handler. */ | |
a3f61dc0 | 385 | newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE; |
1da177e4 LT |
386 | err |= put_user(regs->gpr[1], (unsigned long __user *)newsp); |
387 | ||
388 | /* Set up "regs" so we "return" to the signal handler. */ | |
389 | err |= get_user(regs->nip, &funct_desc_ptr->entry); | |
fab5db97 PM |
390 | /* enter the signal handler in big-endian mode */ |
391 | regs->msr &= ~MSR_LE; | |
1da177e4 LT |
392 | regs->gpr[1] = newsp; |
393 | err |= get_user(regs->gpr[2], &funct_desc_ptr->toc); | |
394 | regs->gpr[3] = signr; | |
395 | regs->result = 0; | |
396 | if (ka->sa.sa_flags & SA_SIGINFO) { | |
397 | err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo); | |
398 | err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc); | |
399 | regs->gpr[6] = (unsigned long) frame; | |
400 | } else { | |
401 | regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext; | |
402 | } | |
403 | if (err) | |
404 | goto badframe; | |
405 | ||
1da177e4 LT |
406 | return 1; |
407 | ||
408 | badframe: | |
409 | #if DEBUG_SIG | |
410 | printk("badframe in setup_rt_frame, regs=%p frame=%p newsp=%lx\n", | |
411 | regs, frame, newsp); | |
412 | #endif | |
d0c3d534 OJ |
413 | if (show_unhandled_signals && printk_ratelimit()) |
414 | printk(regs->msr & MSR_SF ? fmt64 : fmt32, | |
415 | current->comm, current->pid, "setup_rt_frame", | |
416 | (long)frame, regs->nip, regs->link); | |
417 | ||
1da177e4 LT |
418 | force_sigsegv(signr, current); |
419 | return 0; | |
420 | } |