/* * linux/arch/ppc64/kernel/signal.c * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #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 *pinfo; void *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); if (!FULL_REGS(regs)) { /* Zero out the unsaved GPRs to avoid information leak, and set TIF_SAVE_NVGPRS to ensure that the registers do actually get saved later. */ memset(®s->gpr[14], 0, 18 * sizeof(unsigned long)); set_thread_flag(TIF_SAVE_NVGPRS); current_thread_info()->nvgprs_frame = &sc->gp_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; #ifdef CONFIG_ALTIVEC unsigned long msr; #endif 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)); /* skip MSR and 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(); err |= __copy_from_user(¤t->thread.fpr, &sc->fp_regs, FP_REGS_SIZE); #ifdef CONFIG_ALTIVEC err |= __get_user(v_regs, &sc->v_regs); err |= __get_user(msr, &sc->gp_regs[PT_MSR]); if (err) return err; /* 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 */ /* Force reload of FP/VEC */ regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC); 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) { 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->thread.vdso_base) { regs->link = current->thread.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); 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 (!oldset) oldset = ¤t->blocked; signr = get_signal_to_deliver(&info, &ka, regs, NULL); if (signr > 0) { /* 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); return handle_signal(signr, &ka, &info, oldset, regs); } 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; } } return 0; } EXPORT_SYMBOL(do_signal);