3 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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
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.
15 #include <linux/sched.h>
17 #include <linux/smp.h>
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>
28 #include <asm/sigcontext.h>
29 #include <asm/ucontext.h>
30 #include <asm/uaccess.h>
31 #include <asm/pgtable.h>
32 #include <asm/unistd.h>
33 #include <asm/cacheflush.h>
34 #include <asm/syscalls.h>
41 #define GP_REGS_SIZE min(sizeof(elf_gregset_t), sizeof(struct pt_regs))
42 #define FP_REGS_SIZE sizeof(elf_fpregset_t)
44 #define TRAMP_TRACEBACK 3
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.
56 /* sys_rt_sigreturn requires the ucontext be the first field */
58 unsigned long _unused[2];
59 unsigned int tramp[TRAMP_SIZE];
60 struct siginfo __user *pinfo;
63 /* 64 bit ABI allows for 288 bytes below sp before decrementing it. */
65 } __attribute__ ((aligned (16)));
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";
73 * Set up the sigcontext for the signal frame.
76 static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
77 int signr, sigset_t *set, unsigned long handler)
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
88 elf_vrreg_t __user *v_regs = (elf_vrreg_t __user *)(((unsigned long)sc->vmx_reserve + 15) & ~0xful);
90 unsigned long msr = regs->msr;
93 double buf[FP_REGS_SIZE];
97 flush_fp_to_thread(current);
100 err |= __put_user(v_regs, &sc->v_regs);
102 /* save altivec registers */
103 if (current->thread.used_vr) {
104 flush_altivec_to_thread(current);
105 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */
106 err |= __copy_to_user(v_regs, current->thread.vr, 33 * sizeof(vector128));
107 /* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg)
108 * contains valid data.
112 /* We always copy to/from vrsave, it's 0 if we don't have or don't
115 err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
116 #else /* CONFIG_ALTIVEC */
117 err |= __put_user(0, &sc->v_regs);
118 #endif /* CONFIG_ALTIVEC */
119 flush_fp_to_thread(current);
121 /* Copy FP to local buffer then write that out */
122 for (i = 0; i < 32 ; i++)
123 buf[i] = current->thread.TS_FPR(i);
124 memcpy(&buf[i], ¤t->thread.fpscr, sizeof(double));
125 err |= __copy_to_user(&sc->fp_regs, buf, FP_REGS_SIZE);
126 #else /* CONFIG_VSX */
127 /* copy fpr regs and fpscr */
128 err |= __copy_to_user(&sc->fp_regs, ¤t->thread.fpr, FP_REGS_SIZE);
129 #endif /* CONFIG_VSX */
130 err |= __put_user(&sc->gp_regs, &sc->regs);
131 WARN_ON(!FULL_REGS(regs));
132 err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);
133 err |= __put_user(msr, &sc->gp_regs[PT_MSR]);
134 err |= __put_user(signr, &sc->signal);
135 err |= __put_user(handler, &sc->handler);
137 err |= __put_user(set->sig[0], &sc->oldmask);
143 * Restore the sigcontext from the signal frame.
146 static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
147 struct sigcontext __user *sc)
149 #ifdef CONFIG_ALTIVEC
150 elf_vrreg_t __user *v_regs;
153 double buf[FP_REGS_SIZE];
155 unsigned long err = 0;
156 unsigned long save_r13 = 0;
157 elf_greg_t *gregs = (elf_greg_t *)regs;
161 /* If this is not a signal return, we preserve the TLS in r13 */
163 save_r13 = regs->gpr[13];
165 /* copy everything before MSR */
166 err |= __copy_from_user(regs, &sc->gp_regs,
167 PT_MSR*sizeof(unsigned long));
169 /* get MSR separately, transfer the LE bit if doing signal return */
170 err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
172 regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
175 for (i = PT_MSR+1; i <= PT_RESULT; i++) {
178 err |= __get_user(gregs[i], &sc->gp_regs[i]);
182 regs->gpr[13] = save_r13;
184 err |= __get_user(set->sig[0], &sc->oldmask);
187 * Do this before updating the thread state in
188 * current->thread.fpr/vr. That way, if we get preempted
189 * and another task grabs the FPU/Altivec, it won't be
190 * tempted to save the current CPU state into the thread_struct
191 * and corrupt what we are writing there.
193 discard_lazy_cpu_state();
196 * Force reload of FP/VEC.
197 * This has to be done before copying stuff into current->thread.fpr/vr
198 * for the reasons explained in the previous comment.
200 regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC);
202 #ifdef CONFIG_ALTIVEC
203 err |= __get_user(v_regs, &sc->v_regs);
206 if (v_regs && !access_ok(VERIFY_READ, v_regs, 34 * sizeof(vector128)))
208 /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
209 if (v_regs != 0 && (msr & MSR_VEC) != 0)
210 err |= __copy_from_user(current->thread.vr, v_regs,
211 33 * sizeof(vector128));
212 else if (current->thread.used_vr)
213 memset(current->thread.vr, 0, 33 * sizeof(vector128));
214 /* Always get VRSAVE back */
216 err |= __get_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
218 current->thread.vrsave = 0;
219 #endif /* CONFIG_ALTIVEC */
221 /* restore floating point */
222 err |= __copy_from_user(buf, &sc->fp_regs, FP_REGS_SIZE);
225 for (i = 0; i < 32 ; i++)
226 current->thread.TS_FPR(i) = buf[i];
227 memcpy(¤t->thread.fpscr, &buf[i], sizeof(double));
230 err |= __copy_from_user(¤t->thread.fpr, &sc->fp_regs, FP_REGS_SIZE);
236 * Setup the trampoline code on the stack
238 static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
243 /* addi r1, r1, __SIGNAL_FRAMESIZE # Pop the dummy stackframe */
244 err |= __put_user(0x38210000UL | (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]);
245 /* li r0, __NR_[rt_]sigreturn| */
246 err |= __put_user(0x38000000UL | (syscall & 0xffff), &tramp[1]);
248 err |= __put_user(0x44000002UL, &tramp[2]);
250 /* Minimal traceback info */
251 for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
252 err |= __put_user(0, &tramp[i]);
255 flush_icache_range((unsigned long) &tramp[0],
256 (unsigned long) &tramp[TRAMP_SIZE]);
262 * Handle {get,set,swap}_context operations
264 int sys_swapcontext(struct ucontext __user *old_ctx,
265 struct ucontext __user *new_ctx,
266 long ctx_size, long r6, long r7, long r8, struct pt_regs *regs)
271 /* Context size is for future use. Right now, we only make sure
272 * we are passed something we understand
274 if (ctx_size < sizeof(struct ucontext))
277 if (old_ctx != NULL) {
278 if (!access_ok(VERIFY_WRITE, old_ctx, sizeof(*old_ctx))
279 || setup_sigcontext(&old_ctx->uc_mcontext, regs, 0, NULL, 0)
280 || __copy_to_user(&old_ctx->uc_sigmask,
281 ¤t->blocked, sizeof(sigset_t)))
286 if (!access_ok(VERIFY_READ, new_ctx, sizeof(*new_ctx))
287 || __get_user(tmp, (u8 __user *) new_ctx)
288 || __get_user(tmp, (u8 __user *) (new_ctx + 1) - 1))
292 * If we get a fault copying the context into the kernel's
293 * image of the user's registers, we can't just return -EFAULT
294 * because the user's registers will be corrupted. For instance
295 * the NIP value may have been updated but not some of the
296 * other registers. Given that we have done the access_ok
297 * and successfully read the first and last bytes of the region
298 * above, this should only happen in an out-of-memory situation
299 * or if another thread unmaps the region containing the context.
300 * We kill the task with a SIGSEGV in this situation.
303 if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set)))
305 restore_sigmask(&set);
306 if (restore_sigcontext(regs, NULL, 0, &new_ctx->uc_mcontext))
309 /* This returns like rt_sigreturn */
310 set_thread_flag(TIF_RESTOREALL);
316 * Do a signal return; undo the signal stack.
319 int sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5,
320 unsigned long r6, unsigned long r7, unsigned long r8,
321 struct pt_regs *regs)
323 struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
326 /* Always make any pending restarted system calls return -EINTR */
327 current_thread_info()->restart_block.fn = do_no_restart_syscall;
329 if (!access_ok(VERIFY_READ, uc, sizeof(*uc)))
332 if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
334 restore_sigmask(&set);
335 if (restore_sigcontext(regs, NULL, 1, &uc->uc_mcontext))
338 /* do_sigaltstack expects a __user pointer and won't modify
339 * what's in there anyway
341 do_sigaltstack(&uc->uc_stack, NULL, regs->gpr[1]);
343 set_thread_flag(TIF_RESTOREALL);
348 printk("badframe in sys_rt_sigreturn, regs=%p uc=%p &uc->uc_mcontext=%p\n",
349 regs, uc, &uc->uc_mcontext);
351 if (show_unhandled_signals && printk_ratelimit())
352 printk(regs->msr & MSR_SF ? fmt64 : fmt32,
353 current->comm, current->pid, "rt_sigreturn",
354 (long)uc, regs->nip, regs->link);
356 force_sig(SIGSEGV, current);
360 int handle_rt_signal64(int signr, struct k_sigaction *ka, siginfo_t *info,
361 sigset_t *set, struct pt_regs *regs)
363 /* Handler is *really* a pointer to the function descriptor for
364 * the signal routine. The first entry in the function
365 * descriptor is the entry address of signal and the second
366 * entry is the TOC value we need to use.
368 func_descr_t __user *funct_desc_ptr;
369 struct rt_sigframe __user *frame;
370 unsigned long newsp = 0;
373 frame = get_sigframe(ka, regs, sizeof(*frame));
374 if (unlikely(frame == NULL))
377 err |= __put_user(&frame->info, &frame->pinfo);
378 err |= __put_user(&frame->uc, &frame->puc);
379 err |= copy_siginfo_to_user(&frame->info, info);
383 /* Create the ucontext. */
384 err |= __put_user(0, &frame->uc.uc_flags);
385 err |= __put_user(0, &frame->uc.uc_link);
386 err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
387 err |= __put_user(sas_ss_flags(regs->gpr[1]),
388 &frame->uc.uc_stack.ss_flags);
389 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
390 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, signr, NULL,
391 (unsigned long)ka->sa.sa_handler);
392 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
396 /* Make sure signal handler doesn't get spurious FP exceptions */
397 current->thread.fpscr.val = 0;
399 /* Set up to return from userspace. */
400 if (vdso64_rt_sigtramp && current->mm->context.vdso_base) {
401 regs->link = current->mm->context.vdso_base + vdso64_rt_sigtramp;
403 err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
406 regs->link = (unsigned long) &frame->tramp[0];
408 funct_desc_ptr = (func_descr_t __user *) ka->sa.sa_handler;
410 /* Allocate a dummy caller frame for the signal handler. */
411 newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE;
412 err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);
414 /* Set up "regs" so we "return" to the signal handler. */
415 err |= get_user(regs->nip, &funct_desc_ptr->entry);
416 /* enter the signal handler in big-endian mode */
417 regs->msr &= ~MSR_LE;
418 regs->gpr[1] = newsp;
419 err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
420 regs->gpr[3] = signr;
422 if (ka->sa.sa_flags & SA_SIGINFO) {
423 err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo);
424 err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc);
425 regs->gpr[6] = (unsigned long) frame;
427 regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
436 printk("badframe in setup_rt_frame, regs=%p frame=%p newsp=%lx\n",
439 if (show_unhandled_signals && printk_ratelimit())
440 printk(regs->msr & MSR_SF ? fmt64 : fmt32,
441 current->comm, current->pid, "setup_rt_frame",
442 (long)frame, regs->nip, regs->link);
444 force_sigsegv(signr, current);