| /* |
| * PowerPC version |
| * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) |
| * |
| * Derived from "arch/i386/kernel/signal.c" |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| */ |
| |
| #include <linux/sched.h> |
| #include <linux/mm.h> |
| #include <linux/smp.h> |
| #include <linux/kernel.h> |
| #include <linux/signal.h> |
| #include <linux/errno.h> |
| #include <linux/wait.h> |
| #include <linux/unistd.h> |
| #include <linux/stddef.h> |
| #include <linux/elf.h> |
| #include <linux/ptrace.h> |
| #include <linux/module.h> |
| |
| #include <asm/sigcontext.h> |
| #include <asm/ucontext.h> |
| #include <asm/uaccess.h> |
| #include <asm/pgtable.h> |
| #include <asm/unistd.h> |
| #include <asm/cacheflush.h> |
| #include <asm/syscalls.h> |
| #include <asm/vdso.h> |
| |
| #define DEBUG_SIG 0 |
| |
| #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) |
| |
| #define GP_REGS_SIZE min(sizeof(elf_gregset_t), sizeof(struct pt_regs)) |
| #define FP_REGS_SIZE sizeof(elf_fpregset_t) |
| |
| #define TRAMP_TRACEBACK 3 |
| #define TRAMP_SIZE 6 |
| |
| /* |
| * When we have signals to deliver, we set up on the user stack, |
| * going down from the original stack pointer: |
| * 1) a rt_sigframe struct which contains the ucontext |
| * 2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller |
| * frame for the signal handler. |
| */ |
| |
| struct rt_sigframe { |
| /* sys_rt_sigreturn requires the ucontext be the first field */ |
| struct ucontext uc; |
| unsigned long _unused[2]; |
| unsigned int tramp[TRAMP_SIZE]; |
| struct siginfo __user *pinfo; |
| void __user *puc; |
| struct siginfo info; |
| /* 64 bit ABI allows for 288 bytes below sp before decrementing it. */ |
| char abigap[288]; |
| } __attribute__ ((aligned (16))); |
| |
| long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, unsigned long r5, |
| unsigned long r6, unsigned long r7, unsigned long r8, |
| struct pt_regs *regs) |
| { |
| return do_sigaltstack(uss, uoss, regs->gpr[1]); |
| } |
| |
| |
| /* |
| * Set up the sigcontext for the signal frame. |
| */ |
| |
| static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, |
| int signr, sigset_t *set, unsigned long handler) |
| { |
| /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the |
| * process never used altivec yet (MSR_VEC is zero in pt_regs of |
| * the context). This is very important because we must ensure we |
| * don't lose the VRSAVE content that may have been set prior to |
| * the process doing its first vector operation |
| * Userland shall check AT_HWCAP to know wether it can rely on the |
| * v_regs pointer or not |
| */ |
| #ifdef CONFIG_ALTIVEC |
| elf_vrreg_t __user *v_regs = (elf_vrreg_t __user *)(((unsigned long)sc->vmx_reserve + 15) & ~0xful); |
| #endif |
| long err = 0; |
| |
| flush_fp_to_thread(current); |
| |
| #ifdef CONFIG_ALTIVEC |
| err |= __put_user(v_regs, &sc->v_regs); |
| |
| /* save altivec registers */ |
| if (current->thread.used_vr) { |
| flush_altivec_to_thread(current); |
| /* Copy 33 vec registers (vr0..31 and vscr) to the stack */ |
| err |= __copy_to_user(v_regs, current->thread.vr, 33 * sizeof(vector128)); |
| /* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg) |
| * contains valid data. |
| */ |
| regs->msr |= MSR_VEC; |
| } |
| /* We always copy to/from vrsave, it's 0 if we don't have or don't |
| * use altivec. |
| */ |
| err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]); |
| #else /* CONFIG_ALTIVEC */ |
| err |= __put_user(0, &sc->v_regs); |
| #endif /* CONFIG_ALTIVEC */ |
| err |= __put_user(&sc->gp_regs, &sc->regs); |
| WARN_ON(!FULL_REGS(regs)); |
| err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE); |
| err |= __copy_to_user(&sc->fp_regs, ¤t->thread.fpr, FP_REGS_SIZE); |
| err |= __put_user(signr, &sc->signal); |
| err |= __put_user(handler, &sc->handler); |
| if (set != NULL) |
| err |= __put_user(set->sig[0], &sc->oldmask); |
| |
| return err; |
| } |
| |
| /* |
| * Restore the sigcontext from the signal frame. |
| */ |
| |
| static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig, |
| struct sigcontext __user *sc) |
| { |
| #ifdef CONFIG_ALTIVEC |
| elf_vrreg_t __user *v_regs; |
| #endif |
| unsigned long err = 0; |
| unsigned long save_r13 = 0; |
| elf_greg_t *gregs = (elf_greg_t *)regs; |
| unsigned long msr; |
| int i; |
| |
| /* If this is not a signal return, we preserve the TLS in r13 */ |
| if (!sig) |
| save_r13 = regs->gpr[13]; |
| |
| /* copy everything before MSR */ |
| err |= __copy_from_user(regs, &sc->gp_regs, |
| PT_MSR*sizeof(unsigned long)); |
| |
| /* get MSR separately, transfer the LE bit if doing signal return */ |
| err |= __get_user(msr, &sc->gp_regs[PT_MSR]); |
| if (sig) |
| regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE); |
| |
| /* skip SOFTE */ |
| for (i = PT_MSR+1; i <= PT_RESULT; i++) { |
| if (i == PT_SOFTE) |
| continue; |
| err |= __get_user(gregs[i], &sc->gp_regs[i]); |
| } |
| |
| if (!sig) |
| regs->gpr[13] = save_r13; |
| if (set != NULL) |
| err |= __get_user(set->sig[0], &sc->oldmask); |
| |
| /* |
| * Do this before updating the thread state in |
| * current->thread.fpr/vr. That way, if we get preempted |
| * and another task grabs the FPU/Altivec, it won't be |
| * tempted to save the current CPU state into the thread_struct |
| * and corrupt what we are writing there. |
| */ |
| discard_lazy_cpu_state(); |
| |
| /* |
| * Force reload of FP/VEC. |
| * This has to be done before copying stuff into current->thread.fpr/vr |
| * for the reasons explained in the previous comment. |
| */ |
| regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC); |
| |
| err |= __copy_from_user(¤t->thread.fpr, &sc->fp_regs, FP_REGS_SIZE); |
| |
| #ifdef CONFIG_ALTIVEC |
| err |= __get_user(v_regs, &sc->v_regs); |
| if (err) |
| return err; |
| if (v_regs && !access_ok(VERIFY_READ, v_regs, 34 * sizeof(vector128))) |
| return -EFAULT; |
| /* Copy 33 vec registers (vr0..31 and vscr) from the stack */ |
| if (v_regs != 0 && (msr & MSR_VEC) != 0) |
| err |= __copy_from_user(current->thread.vr, v_regs, |
| 33 * sizeof(vector128)); |
| else if (current->thread.used_vr) |
| memset(current->thread.vr, 0, 33 * sizeof(vector128)); |
| /* Always get VRSAVE back */ |
| if (v_regs != 0) |
| err |= __get_user(current->thread.vrsave, (u32 __user *)&v_regs[33]); |
| else |
| current->thread.vrsave = 0; |
| #endif /* CONFIG_ALTIVEC */ |
| |
| return err; |
| } |
| |
| /* |
| * Allocate space for the signal frame |
| */ |
| static inline void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, |
| size_t frame_size) |
| { |
| unsigned long newsp; |
| |
| /* Default to using normal stack */ |
| newsp = regs->gpr[1]; |
| |
| if ((ka->sa.sa_flags & SA_ONSTACK) && current->sas_ss_size) { |
| if (! on_sig_stack(regs->gpr[1])) |
| newsp = (current->sas_ss_sp + current->sas_ss_size); |
| } |
| |
| return (void __user *)((newsp - frame_size) & -16ul); |
| } |
| |
| /* |
| * Setup the trampoline code on the stack |
| */ |
| static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp) |
| { |
| int i; |
| long err = 0; |
| |
| /* addi r1, r1, __SIGNAL_FRAMESIZE # Pop the dummy stackframe */ |
| err |= __put_user(0x38210000UL | (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]); |
| /* li r0, __NR_[rt_]sigreturn| */ |
| err |= __put_user(0x38000000UL | (syscall & 0xffff), &tramp[1]); |
| /* sc */ |
| err |= __put_user(0x44000002UL, &tramp[2]); |
| |
| /* Minimal traceback info */ |
| for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++) |
| err |= __put_user(0, &tramp[i]); |
| |
| if (!err) |
| flush_icache_range((unsigned long) &tramp[0], |
| (unsigned long) &tramp[TRAMP_SIZE]); |
| |
| return err; |
| } |
| |
| /* |
| * Restore the user process's signal mask (also used by signal32.c) |
| */ |
| void restore_sigmask(sigset_t *set) |
| { |
| sigdelsetmask(set, ~_BLOCKABLE); |
| spin_lock_irq(¤t->sighand->siglock); |
| current->blocked = *set; |
| recalc_sigpending(); |
| spin_unlock_irq(¤t->sighand->siglock); |
| } |
| |
| |
| /* |
| * Handle {get,set,swap}_context operations |
| */ |
| int sys_swapcontext(struct ucontext __user *old_ctx, |
| struct ucontext __user *new_ctx, |
| long ctx_size, long r6, long r7, long r8, struct pt_regs *regs) |
| { |
| unsigned char tmp; |
| sigset_t set; |
| |
| /* Context size is for future use. Right now, we only make sure |
| * we are passed something we understand |
| */ |
| if (ctx_size < sizeof(struct ucontext)) |
| return -EINVAL; |
| |
| if (old_ctx != NULL) { |
| if (!access_ok(VERIFY_WRITE, old_ctx, sizeof(*old_ctx)) |
| || setup_sigcontext(&old_ctx->uc_mcontext, regs, 0, NULL, 0) |
| || __copy_to_user(&old_ctx->uc_sigmask, |
| ¤t->blocked, sizeof(sigset_t))) |
| return -EFAULT; |
| } |
| if (new_ctx == NULL) |
| return 0; |
| if (!access_ok(VERIFY_READ, new_ctx, sizeof(*new_ctx)) |
| || __get_user(tmp, (u8 __user *) new_ctx) |
| || __get_user(tmp, (u8 __user *) (new_ctx + 1) - 1)) |
| return -EFAULT; |
| |
| /* |
| * If we get a fault copying the context into the kernel's |
| * image of the user's registers, we can't just return -EFAULT |
| * because the user's registers will be corrupted. For instance |
| * the NIP value may have been updated but not some of the |
| * other registers. Given that we have done the access_ok |
| * and successfully read the first and last bytes of the region |
| * above, this should only happen in an out-of-memory situation |
| * or if another thread unmaps the region containing the context. |
| * We kill the task with a SIGSEGV in this situation. |
| */ |
| |
| if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set))) |
| do_exit(SIGSEGV); |
| restore_sigmask(&set); |
| if (restore_sigcontext(regs, NULL, 0, &new_ctx->uc_mcontext)) |
| do_exit(SIGSEGV); |
| |
| /* This returns like rt_sigreturn */ |
| set_thread_flag(TIF_RESTOREALL); |
| return 0; |
| } |
| |
| |
| /* |
| * Do a signal return; undo the signal stack. |
| */ |
| |
| int sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5, |
| unsigned long r6, unsigned long r7, unsigned long r8, |
| struct pt_regs *regs) |
| { |
| struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1]; |
| sigset_t set; |
| |
| /* Always make any pending restarted system calls return -EINTR */ |
| current_thread_info()->restart_block.fn = do_no_restart_syscall; |
| |
| if (!access_ok(VERIFY_READ, uc, sizeof(*uc))) |
| goto badframe; |
| |
| if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set))) |
| goto badframe; |
| restore_sigmask(&set); |
| if (restore_sigcontext(regs, NULL, 1, &uc->uc_mcontext)) |
| goto badframe; |
| |
| /* do_sigaltstack expects a __user pointer and won't modify |
| * what's in there anyway |
| */ |
| do_sigaltstack(&uc->uc_stack, NULL, regs->gpr[1]); |
| |
| set_thread_flag(TIF_RESTOREALL); |
| return 0; |
| |
| badframe: |
| #if DEBUG_SIG |
| printk("badframe in sys_rt_sigreturn, regs=%p uc=%p &uc->uc_mcontext=%p\n", |
| regs, uc, &uc->uc_mcontext); |
| #endif |
| force_sig(SIGSEGV, current); |
| return 0; |
| } |
| |
| static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info, |
| sigset_t *set, struct pt_regs *regs) |
| { |
| /* Handler is *really* a pointer to the function descriptor for |
| * the signal routine. The first entry in the function |
| * descriptor is the entry address of signal and the second |
| * entry is the TOC value we need to use. |
| */ |
| func_descr_t __user *funct_desc_ptr; |
| struct rt_sigframe __user *frame; |
| unsigned long newsp = 0; |
| long err = 0; |
| |
| frame = get_sigframe(ka, regs, sizeof(*frame)); |
| |
| if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) |
| goto badframe; |
| |
| err |= __put_user(&frame->info, &frame->pinfo); |
| err |= __put_user(&frame->uc, &frame->puc); |
| err |= copy_siginfo_to_user(&frame->info, info); |
| if (err) |
| goto badframe; |
| |
| /* Create the ucontext. */ |
| err |= __put_user(0, &frame->uc.uc_flags); |
| err |= __put_user(0, &frame->uc.uc_link); |
| err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp); |
| err |= __put_user(sas_ss_flags(regs->gpr[1]), |
| &frame->uc.uc_stack.ss_flags); |
| err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); |
| err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, signr, NULL, |
| (unsigned long)ka->sa.sa_handler); |
| err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); |
| if (err) |
| goto badframe; |
| |
| /* Make sure signal handler doesn't get spurious FP exceptions */ |
| current->thread.fpscr.val = 0; |
| |
| /* Set up to return from userspace. */ |
| if (vdso64_rt_sigtramp && current->mm->context.vdso_base) { |
| regs->link = current->mm->context.vdso_base + vdso64_rt_sigtramp; |
| } else { |
| err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]); |
| if (err) |
| goto badframe; |
| regs->link = (unsigned long) &frame->tramp[0]; |
| } |
| funct_desc_ptr = (func_descr_t __user *) ka->sa.sa_handler; |
| |
| /* Allocate a dummy caller frame for the signal handler. */ |
| newsp = (unsigned long)frame - __SIGNAL_FRAMESIZE; |
| err |= put_user(regs->gpr[1], (unsigned long __user *)newsp); |
| |
| /* Set up "regs" so we "return" to the signal handler. */ |
| err |= get_user(regs->nip, &funct_desc_ptr->entry); |
| /* enter the signal handler in big-endian mode */ |
| regs->msr &= ~MSR_LE; |
| regs->gpr[1] = newsp; |
| err |= get_user(regs->gpr[2], &funct_desc_ptr->toc); |
| regs->gpr[3] = signr; |
| regs->result = 0; |
| if (ka->sa.sa_flags & SA_SIGINFO) { |
| err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo); |
| err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc); |
| regs->gpr[6] = (unsigned long) frame; |
| } else { |
| regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext; |
| } |
| if (err) |
| goto badframe; |
| |
| return 1; |
| |
| badframe: |
| #if DEBUG_SIG |
| printk("badframe in setup_rt_frame, regs=%p frame=%p newsp=%lx\n", |
| regs, frame, newsp); |
| #endif |
| force_sigsegv(signr, current); |
| return 0; |
| } |
| |
| |
| /* |
| * OK, we're invoking a handler |
| */ |
| static int handle_signal(unsigned long sig, struct k_sigaction *ka, |
| siginfo_t *info, sigset_t *oldset, struct pt_regs *regs) |
| { |
| int ret; |
| |
| /* Set up Signal Frame */ |
| ret = setup_rt_frame(sig, ka, info, oldset, regs); |
| |
| if (ret) { |
| spin_lock_irq(¤t->sighand->siglock); |
| sigorsets(¤t->blocked, ¤t->blocked, &ka->sa.sa_mask); |
| if (!(ka->sa.sa_flags & SA_NODEFER)) |
| sigaddset(¤t->blocked,sig); |
| recalc_sigpending(); |
| spin_unlock_irq(¤t->sighand->siglock); |
| } |
| |
| return ret; |
| } |
| |
| static inline void syscall_restart(struct pt_regs *regs, struct k_sigaction *ka) |
| { |
| switch ((int)regs->result) { |
| case -ERESTART_RESTARTBLOCK: |
| case -ERESTARTNOHAND: |
| /* ERESTARTNOHAND means that the syscall should only be |
| * restarted if there was no handler for the signal, and since |
| * we only get here if there is a handler, we dont restart. |
| */ |
| regs->result = -EINTR; |
| regs->gpr[3] = EINTR; |
| regs->ccr |= 0x10000000; |
| break; |
| case -ERESTARTSYS: |
| /* ERESTARTSYS means to restart the syscall if there is no |
| * handler or the handler was registered with SA_RESTART |
| */ |
| if (!(ka->sa.sa_flags & SA_RESTART)) { |
| regs->result = -EINTR; |
| regs->gpr[3] = EINTR; |
| regs->ccr |= 0x10000000; |
| break; |
| } |
| /* fallthrough */ |
| case -ERESTARTNOINTR: |
| /* ERESTARTNOINTR means that the syscall should be |
| * called again after the signal handler returns. |
| */ |
| regs->gpr[3] = regs->orig_gpr3; |
| regs->nip -= 4; |
| regs->result = 0; |
| break; |
| } |
| } |
| |
| /* |
| * Note that 'init' is a special process: it doesn't get signals it doesn't |
| * want to handle. Thus you cannot kill init even with a SIGKILL even by |
| * mistake. |
| */ |
| int do_signal(sigset_t *oldset, struct pt_regs *regs) |
| { |
| siginfo_t info; |
| int signr; |
| struct k_sigaction ka; |
| |
| /* |
| * If the current thread is 32 bit - invoke the |
| * 32 bit signal handling code |
| */ |
| if (test_thread_flag(TIF_32BIT)) |
| return do_signal32(oldset, regs); |
| |
| if (test_thread_flag(TIF_RESTORE_SIGMASK)) |
| oldset = ¤t->saved_sigmask; |
| else if (!oldset) |
| oldset = ¤t->blocked; |
| |
| signr = get_signal_to_deliver(&info, &ka, regs, NULL); |
| if (signr > 0) { |
| int ret; |
| |
| /* Whee! Actually deliver the signal. */ |
| if (TRAP(regs) == 0x0C00) |
| syscall_restart(regs, &ka); |
| |
| /* |
| * Reenable the DABR before delivering the signal to |
| * user space. The DABR will have been cleared if it |
| * triggered inside the kernel. |
| */ |
| if (current->thread.dabr) |
| set_dabr(current->thread.dabr); |
| |
| ret = handle_signal(signr, &ka, &info, oldset, regs); |
| |
| /* If a signal was successfully delivered, the saved sigmask is in |
| its frame, and we can clear the TIF_RESTORE_SIGMASK flag */ |
| if (ret && test_thread_flag(TIF_RESTORE_SIGMASK)) |
| clear_thread_flag(TIF_RESTORE_SIGMASK); |
| |
| return ret; |
| } |
| |
| if (TRAP(regs) == 0x0C00) { /* System Call! */ |
| if ((int)regs->result == -ERESTARTNOHAND || |
| (int)regs->result == -ERESTARTSYS || |
| (int)regs->result == -ERESTARTNOINTR) { |
| regs->gpr[3] = regs->orig_gpr3; |
| regs->nip -= 4; /* Back up & retry system call */ |
| regs->result = 0; |
| } else if ((int)regs->result == -ERESTART_RESTARTBLOCK) { |
| regs->gpr[0] = __NR_restart_syscall; |
| regs->nip -= 4; |
| regs->result = 0; |
| } |
| } |
| /* No signal to deliver -- put the saved sigmask back */ |
| if (test_thread_flag(TIF_RESTORE_SIGMASK)) { |
| clear_thread_flag(TIF_RESTORE_SIGMASK); |
| sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(do_signal); |