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 flush_fp_to_thread(current);
96 err |= __put_user(v_regs, &sc->v_regs);
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.
108 /* We always copy to/from vrsave, it's 0 if we don't have or don't
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 flush_fp_to_thread(current);
116 /* copy fpr regs and fpscr */
117 err |= copy_fpr_to_user(&sc->fp_regs, current);
120 * Copy VSX low doubleword to local buffer for formatting,
121 * then out to userspace. Update v_regs to point after the
124 if (current->thread.used_vsr) {
125 flush_vsx_to_thread(current);
126 v_regs += ELF_NVRREG;
127 err |= copy_vsx_to_user(v_regs, current);
128 /* set MSR_VSX in the MSR value in the frame to
129 * indicate that sc->vs_reg) contains valid data.
133 #endif /* CONFIG_VSX */
134 err |= __put_user(&sc->gp_regs, &sc->regs);
135 WARN_ON(!FULL_REGS(regs));
136 err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);
137 err |= __put_user(msr, &sc->gp_regs[PT_MSR]);
138 err |= __put_user(signr, &sc->signal);
139 err |= __put_user(handler, &sc->handler);
141 err |= __put_user(set->sig[0], &sc->oldmask);
147 * Restore the sigcontext from the signal frame.
150 static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
151 struct sigcontext __user *sc)
153 #ifdef CONFIG_ALTIVEC
154 elf_vrreg_t __user *v_regs;
156 unsigned long err = 0;
157 unsigned long save_r13 = 0;
163 /* If this is not a signal return, we preserve the TLS in r13 */
165 save_r13 = regs->gpr[13];
168 err |= __copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr));
169 err |= __get_user(regs->nip, &sc->gp_regs[PT_NIP]);
170 /* get MSR separately, transfer the LE bit if doing signal return */
171 err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
173 regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
174 err |= __get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3]);
175 err |= __get_user(regs->ctr, &sc->gp_regs[PT_CTR]);
176 err |= __get_user(regs->link, &sc->gp_regs[PT_LNK]);
177 err |= __get_user(regs->xer, &sc->gp_regs[PT_XER]);
178 err |= __get_user(regs->ccr, &sc->gp_regs[PT_CCR]);
180 err |= __get_user(regs->trap, &sc->gp_regs[PT_TRAP]);
181 err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
182 err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
183 err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
186 regs->gpr[13] = save_r13;
188 err |= __get_user(set->sig[0], &sc->oldmask);
191 * Do this before updating the thread state in
192 * current->thread.fpr/vr. That way, if we get preempted
193 * and another task grabs the FPU/Altivec, it won't be
194 * tempted to save the current CPU state into the thread_struct
195 * and corrupt what we are writing there.
197 discard_lazy_cpu_state();
200 * Force reload of FP/VEC.
201 * This has to be done before copying stuff into current->thread.fpr/vr
202 * for the reasons explained in the previous comment.
204 regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
206 #ifdef CONFIG_ALTIVEC
207 err |= __get_user(v_regs, &sc->v_regs);
210 if (v_regs && !access_ok(VERIFY_READ, v_regs, 34 * sizeof(vector128)))
212 /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
213 if (v_regs != 0 && (msr & MSR_VEC) != 0)
214 err |= __copy_from_user(current->thread.vr, v_regs,
215 33 * sizeof(vector128));
216 else if (current->thread.used_vr)
217 memset(current->thread.vr, 0, 33 * sizeof(vector128));
218 /* Always get VRSAVE back */
220 err |= __get_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
222 current->thread.vrsave = 0;
223 #endif /* CONFIG_ALTIVEC */
224 /* restore floating point */
225 err |= copy_fpr_from_user(current, &sc->fp_regs);
228 * Get additional VSX data. Update v_regs to point after the
229 * VMX data. Copy VSX low doubleword from userspace to local
230 * buffer for formatting, then into the taskstruct.
232 v_regs += ELF_NVRREG;
233 if ((msr & MSR_VSX) != 0)
234 err |= copy_vsx_from_user(current, v_regs);
236 for (i = 0; i < 32 ; i++)
237 current->thread.fpr[i][TS_VSRLOWOFFSET] = 0;
245 * Setup the trampoline code on the stack
247 static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
252 /* addi r1, r1, __SIGNAL_FRAMESIZE # Pop the dummy stackframe */
253 err |= __put_user(0x38210000UL | (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]);
254 /* li r0, __NR_[rt_]sigreturn| */
255 err |= __put_user(0x38000000UL | (syscall & 0xffff), &tramp[1]);
257 err |= __put_user(0x44000002UL, &tramp[2]);
259 /* Minimal traceback info */
260 for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
261 err |= __put_user(0, &tramp[i]);
264 flush_icache_range((unsigned long) &tramp[0],
265 (unsigned long) &tramp[TRAMP_SIZE]);
271 * Handle {get,set,swap}_context operations
273 int sys_swapcontext(struct ucontext __user *old_ctx,
274 struct ucontext __user *new_ctx,
275 long ctx_size, long r6, long r7, long r8, struct pt_regs *regs)
280 /* Context size is for future use. Right now, we only make sure
281 * we are passed something we understand
283 if (ctx_size < sizeof(struct ucontext))
286 if (old_ctx != NULL) {
287 if (!access_ok(VERIFY_WRITE, old_ctx, sizeof(*old_ctx))
288 || setup_sigcontext(&old_ctx->uc_mcontext, regs, 0, NULL, 0)
289 || __copy_to_user(&old_ctx->uc_sigmask,
290 ¤t->blocked, sizeof(sigset_t)))
295 if (!access_ok(VERIFY_READ, new_ctx, sizeof(*new_ctx))
296 || __get_user(tmp, (u8 __user *) new_ctx)
297 || __get_user(tmp, (u8 __user *) (new_ctx + 1) - 1))
301 * If we get a fault copying the context into the kernel's
302 * image of the user's registers, we can't just return -EFAULT
303 * because the user's registers will be corrupted. For instance
304 * the NIP value may have been updated but not some of the
305 * other registers. Given that we have done the access_ok
306 * and successfully read the first and last bytes of the region
307 * above, this should only happen in an out-of-memory situation
308 * or if another thread unmaps the region containing the context.
309 * We kill the task with a SIGSEGV in this situation.
312 if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set)))
314 restore_sigmask(&set);
315 if (restore_sigcontext(regs, NULL, 0, &new_ctx->uc_mcontext))
318 /* This returns like rt_sigreturn */
319 set_thread_flag(TIF_RESTOREALL);
325 * Do a signal return; undo the signal stack.
328 int sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5,
329 unsigned long r6, unsigned long r7, unsigned long r8,
330 struct pt_regs *regs)
332 struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
335 /* Always make any pending restarted system calls return -EINTR */
336 current_thread_info()->restart_block.fn = do_no_restart_syscall;
338 if (!access_ok(VERIFY_READ, uc, sizeof(*uc)))
341 if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
343 restore_sigmask(&set);
344 if (restore_sigcontext(regs, NULL, 1, &uc->uc_mcontext))
347 /* do_sigaltstack expects a __user pointer and won't modify
348 * what's in there anyway
350 do_sigaltstack(&uc->uc_stack, NULL, regs->gpr[1]);
352 set_thread_flag(TIF_RESTOREALL);
357 printk("badframe in sys_rt_sigreturn, regs=%p uc=%p &uc->uc_mcontext=%p\n",
358 regs, uc, &uc->uc_mcontext);
360 if (show_unhandled_signals && printk_ratelimit())
361 printk(regs->msr & MSR_SF ? fmt64 : fmt32,
362 current->comm, current->pid, "rt_sigreturn",
363 (long)uc, regs->nip, regs->link);
365 force_sig(SIGSEGV, current);
369 int handle_rt_signal64(int signr, struct k_sigaction *ka, siginfo_t *info,
370 sigset_t *set, struct pt_regs *regs)
372 /* Handler is *really* a pointer to the function descriptor for
373 * the signal routine. The first entry in the function
374 * descriptor is the entry address of signal and the second
375 * entry is the TOC value we need to use.
377 func_descr_t __user *funct_desc_ptr;
378 struct rt_sigframe __user *frame;
379 unsigned long newsp = 0;
382 frame = get_sigframe(ka, regs, sizeof(*frame));
383 if (unlikely(frame == NULL))
386 err |= __put_user(&frame->info, &frame->pinfo);
387 err |= __put_user(&frame->uc, &frame->puc);
388 err |= copy_siginfo_to_user(&frame->info, info);
392 /* Create the ucontext. */
393 err |= __put_user(0, &frame->uc.uc_flags);
394 err |= __put_user(0, &frame->uc.uc_link);
395 err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
396 err |= __put_user(sas_ss_flags(regs->gpr[1]),
397 &frame->uc.uc_stack.ss_flags);
398 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
399 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, signr, NULL,
400 (unsigned long)ka->sa.sa_handler);
401 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
405 /* Make sure signal handler doesn't get spurious FP exceptions */
406 current->thread.fpscr.val = 0;
408 /* Set up to return from userspace. */
409 if (vdso64_rt_sigtramp && current->mm->context.vdso_base) {
410 regs->link = current->mm->context.vdso_base + vdso64_rt_sigtramp;
412 err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
415 regs->link = (unsigned long) &frame->tramp[0];
417 funct_desc_ptr = (func_descr_t __user *) ka->sa.sa_handler;
419 /* Allocate a dummy caller frame for the signal handler. */
420 newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE;
421 err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);
423 /* Set up "regs" so we "return" to the signal handler. */
424 err |= get_user(regs->nip, &funct_desc_ptr->entry);
425 /* enter the signal handler in big-endian mode */
426 regs->msr &= ~MSR_LE;
427 regs->gpr[1] = newsp;
428 err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
429 regs->gpr[3] = signr;
431 if (ka->sa.sa_flags & SA_SIGINFO) {
432 err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo);
433 err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc);
434 regs->gpr[6] = (unsigned long) frame;
436 regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
445 printk("badframe in setup_rt_frame, regs=%p frame=%p newsp=%lx\n",
448 if (show_unhandled_signals && printk_ratelimit())
449 printk(regs->msr & MSR_SF ? fmt64 : fmt32,
450 current->comm, current->pid, "setup_rt_frame",
451 (long)frame, regs->nip, regs->link);
453 force_sigsegv(signr, current);