1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Based on arch/arm/kernel/signal.c |
4 | * |
5 | * Copyright (C) 1995-2009 Russell King |
6 | * Copyright (C) 2012 ARM Ltd. |
7 | * Modified by Will Deacon <will.deacon@arm.com> |
8 | */ |
9 | |
10 | #include <linux/compat.h> |
11 | #include <linux/signal.h> |
12 | #include <linux/syscalls.h> |
13 | #include <linux/ratelimit.h> |
14 | |
15 | #include <asm/esr.h> |
16 | #include <asm/fpsimd.h> |
17 | #include <asm/signal32.h> |
18 | #include <asm/traps.h> |
19 | #include <linux/uaccess.h> |
20 | #include <asm/unistd.h> |
21 | #include <asm/vdso.h> |
22 | |
23 | struct compat_vfp_sigframe { |
24 | compat_ulong_t magic; |
25 | compat_ulong_t size; |
26 | struct compat_user_vfp { |
27 | compat_u64 fpregs[32]; |
28 | compat_ulong_t fpscr; |
29 | } ufp; |
30 | struct compat_user_vfp_exc { |
31 | compat_ulong_t fpexc; |
32 | compat_ulong_t fpinst; |
33 | compat_ulong_t fpinst2; |
34 | } ufp_exc; |
35 | } __attribute__((__aligned__(8))); |
36 | |
37 | #define VFP_MAGIC 0x56465001 |
38 | #define VFP_STORAGE_SIZE sizeof(struct compat_vfp_sigframe) |
39 | |
40 | #define FSR_WRITE_SHIFT (11) |
41 | |
42 | struct compat_aux_sigframe { |
43 | struct compat_vfp_sigframe vfp; |
44 | |
45 | /* Something that isn't a valid magic number for any coprocessor. */ |
46 | unsigned long end_magic; |
47 | } __attribute__((__aligned__(8))); |
48 | |
49 | static inline int put_sigset_t(compat_sigset_t __user *uset, sigset_t *set) |
50 | { |
51 | compat_sigset_t cset; |
52 | |
53 | cset.sig[0] = set->sig[0] & 0xffffffffull; |
54 | cset.sig[1] = set->sig[0] >> 32; |
55 | |
56 | return copy_to_user(to: uset, from: &cset, n: sizeof(*uset)); |
57 | } |
58 | |
59 | static inline int get_sigset_t(sigset_t *set, |
60 | const compat_sigset_t __user *uset) |
61 | { |
62 | compat_sigset_t s32; |
63 | |
64 | if (copy_from_user(to: &s32, from: uset, n: sizeof(*uset))) |
65 | return -EFAULT; |
66 | |
67 | set->sig[0] = s32.sig[0] | (((long)s32.sig[1]) << 32); |
68 | return 0; |
69 | } |
70 | |
71 | /* |
72 | * VFP save/restore code. |
73 | * |
74 | * We have to be careful with endianness, since the fpsimd context-switch |
75 | * code operates on 128-bit (Q) register values whereas the compat ABI |
76 | * uses an array of 64-bit (D) registers. Consequently, we need to swap |
77 | * the two halves of each Q register when running on a big-endian CPU. |
78 | */ |
79 | union __fpsimd_vreg { |
80 | __uint128_t raw; |
81 | struct { |
82 | #ifdef __AARCH64EB__ |
83 | u64 hi; |
84 | u64 lo; |
85 | #else |
86 | u64 lo; |
87 | u64 hi; |
88 | #endif |
89 | }; |
90 | }; |
91 | |
92 | static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame) |
93 | { |
94 | struct user_fpsimd_state const *fpsimd = |
95 | ¤t->thread.uw.fpsimd_state; |
96 | compat_ulong_t magic = VFP_MAGIC; |
97 | compat_ulong_t size = VFP_STORAGE_SIZE; |
98 | compat_ulong_t fpscr, fpexc; |
99 | int i, err = 0; |
100 | |
101 | /* |
102 | * Save the hardware registers to the fpsimd_state structure. |
103 | * Note that this also saves V16-31, which aren't visible |
104 | * in AArch32. |
105 | */ |
106 | fpsimd_signal_preserve_current_state(); |
107 | |
108 | /* Place structure header on the stack */ |
109 | __put_user_error(magic, &frame->magic, err); |
110 | __put_user_error(size, &frame->size, err); |
111 | |
112 | /* |
113 | * Now copy the FP registers. Since the registers are packed, |
114 | * we can copy the prefix we want (V0-V15) as it is. |
115 | */ |
116 | for (i = 0; i < ARRAY_SIZE(frame->ufp.fpregs); i += 2) { |
117 | union __fpsimd_vreg vreg = { |
118 | .raw = fpsimd->vregs[i >> 1], |
119 | }; |
120 | |
121 | __put_user_error(vreg.lo, &frame->ufp.fpregs[i], err); |
122 | __put_user_error(vreg.hi, &frame->ufp.fpregs[i + 1], err); |
123 | } |
124 | |
125 | /* Create an AArch32 fpscr from the fpsr and the fpcr. */ |
126 | fpscr = (fpsimd->fpsr & VFP_FPSCR_STAT_MASK) | |
127 | (fpsimd->fpcr & VFP_FPSCR_CTRL_MASK); |
128 | __put_user_error(fpscr, &frame->ufp.fpscr, err); |
129 | |
130 | /* |
131 | * The exception register aren't available so we fake up a |
132 | * basic FPEXC and zero everything else. |
133 | */ |
134 | fpexc = (1 << 30); |
135 | __put_user_error(fpexc, &frame->ufp_exc.fpexc, err); |
136 | __put_user_error(0, &frame->ufp_exc.fpinst, err); |
137 | __put_user_error(0, &frame->ufp_exc.fpinst2, err); |
138 | |
139 | return err ? -EFAULT : 0; |
140 | } |
141 | |
142 | static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame) |
143 | { |
144 | struct user_fpsimd_state fpsimd; |
145 | compat_ulong_t magic = VFP_MAGIC; |
146 | compat_ulong_t size = VFP_STORAGE_SIZE; |
147 | compat_ulong_t fpscr; |
148 | int i, err = 0; |
149 | |
150 | __get_user_error(magic, &frame->magic, err); |
151 | __get_user_error(size, &frame->size, err); |
152 | |
153 | if (err) |
154 | return -EFAULT; |
155 | if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE) |
156 | return -EINVAL; |
157 | |
158 | /* Copy the FP registers into the start of the fpsimd_state. */ |
159 | for (i = 0; i < ARRAY_SIZE(frame->ufp.fpregs); i += 2) { |
160 | union __fpsimd_vreg vreg; |
161 | |
162 | __get_user_error(vreg.lo, &frame->ufp.fpregs[i], err); |
163 | __get_user_error(vreg.hi, &frame->ufp.fpregs[i + 1], err); |
164 | fpsimd.vregs[i >> 1] = vreg.raw; |
165 | } |
166 | |
167 | /* Extract the fpsr and the fpcr from the fpscr */ |
168 | __get_user_error(fpscr, &frame->ufp.fpscr, err); |
169 | fpsimd.fpsr = fpscr & VFP_FPSCR_STAT_MASK; |
170 | fpsimd.fpcr = fpscr & VFP_FPSCR_CTRL_MASK; |
171 | |
172 | /* |
173 | * We don't need to touch the exception register, so |
174 | * reload the hardware state. |
175 | */ |
176 | if (!err) |
177 | fpsimd_update_current_state(&fpsimd); |
178 | |
179 | return err ? -EFAULT : 0; |
180 | } |
181 | |
182 | static int compat_restore_sigframe(struct pt_regs *regs, |
183 | struct compat_sigframe __user *sf) |
184 | { |
185 | int err; |
186 | sigset_t set; |
187 | struct compat_aux_sigframe __user *aux; |
188 | unsigned long psr; |
189 | |
190 | err = get_sigset_t(set: &set, uset: &sf->uc.uc_sigmask); |
191 | if (err == 0) |
192 | set_current_blocked(&set); |
193 | |
194 | __get_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err); |
195 | __get_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err); |
196 | __get_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err); |
197 | __get_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err); |
198 | __get_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err); |
199 | __get_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err); |
200 | __get_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err); |
201 | __get_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err); |
202 | __get_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err); |
203 | __get_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err); |
204 | __get_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err); |
205 | __get_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err); |
206 | __get_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err); |
207 | __get_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err); |
208 | __get_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err); |
209 | __get_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err); |
210 | __get_user_error(psr, &sf->uc.uc_mcontext.arm_cpsr, err); |
211 | |
212 | regs->pstate = compat_psr_to_pstate(psr); |
213 | |
214 | /* |
215 | * Avoid compat_sys_sigreturn() restarting. |
216 | */ |
217 | forget_syscall(regs); |
218 | |
219 | err |= !valid_user_regs(®s->user_regs, current); |
220 | |
221 | aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace; |
222 | if (err == 0 && system_supports_fpsimd()) |
223 | err |= compat_restore_vfp_context(frame: &aux->vfp); |
224 | |
225 | return err; |
226 | } |
227 | |
228 | COMPAT_SYSCALL_DEFINE0(sigreturn) |
229 | { |
230 | struct pt_regs *regs = current_pt_regs(); |
231 | struct compat_sigframe __user *frame; |
232 | |
233 | /* Always make any pending restarted system calls return -EINTR */ |
234 | current->restart_block.fn = do_no_restart_syscall; |
235 | |
236 | /* |
237 | * Since we stacked the signal on a 64-bit boundary, |
238 | * then 'sp' should be word aligned here. If it's |
239 | * not, then the user is trying to mess with us. |
240 | */ |
241 | if (regs->compat_sp & 7) |
242 | goto badframe; |
243 | |
244 | frame = (struct compat_sigframe __user *)regs->compat_sp; |
245 | |
246 | if (!access_ok(frame, sizeof (*frame))) |
247 | goto badframe; |
248 | |
249 | if (compat_restore_sigframe(regs, sf: frame)) |
250 | goto badframe; |
251 | |
252 | return regs->regs[0]; |
253 | |
254 | badframe: |
255 | arm64_notify_segfault(regs->compat_sp); |
256 | return 0; |
257 | } |
258 | |
259 | COMPAT_SYSCALL_DEFINE0(rt_sigreturn) |
260 | { |
261 | struct pt_regs *regs = current_pt_regs(); |
262 | struct compat_rt_sigframe __user *frame; |
263 | |
264 | /* Always make any pending restarted system calls return -EINTR */ |
265 | current->restart_block.fn = do_no_restart_syscall; |
266 | |
267 | /* |
268 | * Since we stacked the signal on a 64-bit boundary, |
269 | * then 'sp' should be word aligned here. If it's |
270 | * not, then the user is trying to mess with us. |
271 | */ |
272 | if (regs->compat_sp & 7) |
273 | goto badframe; |
274 | |
275 | frame = (struct compat_rt_sigframe __user *)regs->compat_sp; |
276 | |
277 | if (!access_ok(frame, sizeof (*frame))) |
278 | goto badframe; |
279 | |
280 | if (compat_restore_sigframe(regs, sf: &frame->sig)) |
281 | goto badframe; |
282 | |
283 | if (compat_restore_altstack(uss: &frame->sig.uc.uc_stack)) |
284 | goto badframe; |
285 | |
286 | return regs->regs[0]; |
287 | |
288 | badframe: |
289 | arm64_notify_segfault(regs->compat_sp); |
290 | return 0; |
291 | } |
292 | |
293 | static void __user *compat_get_sigframe(struct ksignal *ksig, |
294 | struct pt_regs *regs, |
295 | int framesize) |
296 | { |
297 | compat_ulong_t sp = sigsp(sp: regs->compat_sp, ksig); |
298 | void __user *frame; |
299 | |
300 | /* |
301 | * ATPCS B01 mandates 8-byte alignment |
302 | */ |
303 | frame = compat_ptr(uptr: (compat_uptr_t)((sp - framesize) & ~7)); |
304 | |
305 | /* |
306 | * Check that we can actually write to the signal frame. |
307 | */ |
308 | if (!access_ok(frame, framesize)) |
309 | frame = NULL; |
310 | |
311 | return frame; |
312 | } |
313 | |
314 | static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka, |
315 | compat_ulong_t __user *rc, void __user *frame, |
316 | int usig) |
317 | { |
318 | compat_ulong_t handler = ptr_to_compat(uptr: ka->sa.sa_handler); |
319 | compat_ulong_t retcode; |
320 | compat_ulong_t spsr = regs->pstate & ~(PSR_f | PSR_AA32_E_BIT); |
321 | int thumb; |
322 | |
323 | /* Check if the handler is written for ARM or Thumb */ |
324 | thumb = handler & 1; |
325 | |
326 | if (thumb) |
327 | spsr |= PSR_AA32_T_BIT; |
328 | else |
329 | spsr &= ~PSR_AA32_T_BIT; |
330 | |
331 | /* The IT state must be cleared for both ARM and Thumb-2 */ |
332 | spsr &= ~PSR_AA32_IT_MASK; |
333 | |
334 | /* Restore the original endianness */ |
335 | spsr |= PSR_AA32_ENDSTATE; |
336 | |
337 | if (ka->sa.sa_flags & SA_RESTORER) { |
338 | retcode = ptr_to_compat(uptr: ka->sa.sa_restorer); |
339 | } else { |
340 | /* Set up sigreturn pointer */ |
341 | unsigned int idx = thumb << 1; |
342 | |
343 | if (ka->sa.sa_flags & SA_SIGINFO) |
344 | idx += 3; |
345 | |
346 | retcode = (unsigned long)current->mm->context.sigpage + |
347 | (idx << 2) + thumb; |
348 | } |
349 | |
350 | regs->regs[0] = usig; |
351 | regs->compat_sp = ptr_to_compat(uptr: frame); |
352 | regs->compat_lr = retcode; |
353 | regs->pc = handler; |
354 | regs->pstate = spsr; |
355 | } |
356 | |
357 | static int compat_setup_sigframe(struct compat_sigframe __user *sf, |
358 | struct pt_regs *regs, sigset_t *set) |
359 | { |
360 | struct compat_aux_sigframe __user *aux; |
361 | unsigned long psr = pstate_to_compat_psr(regs->pstate); |
362 | int err = 0; |
363 | |
364 | __put_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err); |
365 | __put_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err); |
366 | __put_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err); |
367 | __put_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err); |
368 | __put_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err); |
369 | __put_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err); |
370 | __put_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err); |
371 | __put_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err); |
372 | __put_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err); |
373 | __put_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err); |
374 | __put_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err); |
375 | __put_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err); |
376 | __put_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err); |
377 | __put_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err); |
378 | __put_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err); |
379 | __put_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err); |
380 | __put_user_error(psr, &sf->uc.uc_mcontext.arm_cpsr, err); |
381 | |
382 | __put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.trap_no, err); |
383 | /* set the compat FSR WnR */ |
384 | __put_user_error(!!(current->thread.fault_code & ESR_ELx_WNR) << |
385 | FSR_WRITE_SHIFT, &sf->uc.uc_mcontext.error_code, err); |
386 | __put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err); |
387 | __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err); |
388 | |
389 | err |= put_sigset_t(uset: &sf->uc.uc_sigmask, set); |
390 | |
391 | aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace; |
392 | |
393 | if (err == 0 && system_supports_fpsimd()) |
394 | err |= compat_preserve_vfp_context(frame: &aux->vfp); |
395 | __put_user_error(0, &aux->end_magic, err); |
396 | |
397 | return err; |
398 | } |
399 | |
400 | /* |
401 | * 32-bit signal handling routines called from signal.c |
402 | */ |
403 | int compat_setup_rt_frame(int usig, struct ksignal *ksig, |
404 | sigset_t *set, struct pt_regs *regs) |
405 | { |
406 | struct compat_rt_sigframe __user *frame; |
407 | int err = 0; |
408 | |
409 | frame = compat_get_sigframe(ksig, regs, sizeof(*frame)); |
410 | |
411 | if (!frame) |
412 | return 1; |
413 | |
414 | err |= copy_siginfo_to_user32(to: &frame->info, from: &ksig->info); |
415 | |
416 | __put_user_error(0, &frame->sig.uc.uc_flags, err); |
417 | __put_user_error(0, &frame->sig.uc.uc_link, err); |
418 | |
419 | err |= __compat_save_altstack(&frame->sig.uc.uc_stack, regs->compat_sp); |
420 | |
421 | err |= compat_setup_sigframe(sf: &frame->sig, regs, set); |
422 | |
423 | if (err == 0) { |
424 | compat_setup_return(regs, ka: &ksig->ka, rc: frame->sig.retcode, frame, usig); |
425 | regs->regs[1] = (compat_ulong_t)(unsigned long)&frame->info; |
426 | regs->regs[2] = (compat_ulong_t)(unsigned long)&frame->sig.uc; |
427 | } |
428 | |
429 | return err; |
430 | } |
431 | |
432 | int compat_setup_frame(int usig, struct ksignal *ksig, sigset_t *set, |
433 | struct pt_regs *regs) |
434 | { |
435 | struct compat_sigframe __user *frame; |
436 | int err = 0; |
437 | |
438 | frame = compat_get_sigframe(ksig, regs, sizeof(*frame)); |
439 | |
440 | if (!frame) |
441 | return 1; |
442 | |
443 | __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err); |
444 | |
445 | err |= compat_setup_sigframe(sf: frame, regs, set); |
446 | if (err == 0) |
447 | compat_setup_return(regs, ka: &ksig->ka, rc: frame->retcode, frame, usig); |
448 | |
449 | return err; |
450 | } |
451 | |
452 | void compat_setup_restart_syscall(struct pt_regs *regs) |
453 | { |
454 | regs->regs[7] = __NR_compat_restart_syscall; |
455 | } |
456 | |
457 | /* |
458 | * Compile-time assertions for siginfo_t offsets. Check NSIG* as well, as |
459 | * changes likely come with new fields that should be added below. |
460 | */ |
461 | static_assert(NSIGILL == 11); |
462 | static_assert(NSIGFPE == 15); |
463 | static_assert(NSIGSEGV == 10); |
464 | static_assert(NSIGBUS == 5); |
465 | static_assert(NSIGTRAP == 6); |
466 | static_assert(NSIGCHLD == 6); |
467 | static_assert(NSIGSYS == 2); |
468 | static_assert(sizeof(compat_siginfo_t) == 128); |
469 | static_assert(__alignof__(compat_siginfo_t) == 4); |
470 | static_assert(offsetof(compat_siginfo_t, si_signo) == 0x00); |
471 | static_assert(offsetof(compat_siginfo_t, si_errno) == 0x04); |
472 | static_assert(offsetof(compat_siginfo_t, si_code) == 0x08); |
473 | static_assert(offsetof(compat_siginfo_t, si_pid) == 0x0c); |
474 | static_assert(offsetof(compat_siginfo_t, si_uid) == 0x10); |
475 | static_assert(offsetof(compat_siginfo_t, si_tid) == 0x0c); |
476 | static_assert(offsetof(compat_siginfo_t, si_overrun) == 0x10); |
477 | static_assert(offsetof(compat_siginfo_t, si_status) == 0x14); |
478 | static_assert(offsetof(compat_siginfo_t, si_utime) == 0x18); |
479 | static_assert(offsetof(compat_siginfo_t, si_stime) == 0x1c); |
480 | static_assert(offsetof(compat_siginfo_t, si_value) == 0x14); |
481 | static_assert(offsetof(compat_siginfo_t, si_int) == 0x14); |
482 | static_assert(offsetof(compat_siginfo_t, si_ptr) == 0x14); |
483 | static_assert(offsetof(compat_siginfo_t, si_addr) == 0x0c); |
484 | static_assert(offsetof(compat_siginfo_t, si_addr_lsb) == 0x10); |
485 | static_assert(offsetof(compat_siginfo_t, si_lower) == 0x14); |
486 | static_assert(offsetof(compat_siginfo_t, si_upper) == 0x18); |
487 | static_assert(offsetof(compat_siginfo_t, si_pkey) == 0x14); |
488 | static_assert(offsetof(compat_siginfo_t, si_perf_data) == 0x10); |
489 | static_assert(offsetof(compat_siginfo_t, si_perf_type) == 0x14); |
490 | static_assert(offsetof(compat_siginfo_t, si_perf_flags) == 0x18); |
491 | static_assert(offsetof(compat_siginfo_t, si_band) == 0x0c); |
492 | static_assert(offsetof(compat_siginfo_t, si_fd) == 0x10); |
493 | static_assert(offsetof(compat_siginfo_t, si_call_addr) == 0x0c); |
494 | static_assert(offsetof(compat_siginfo_t, si_syscall) == 0x10); |
495 | static_assert(offsetof(compat_siginfo_t, si_arch) == 0x14); |
496 | |