/* * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 1991, 1992 Linus Torvalds * Copyright (C) 1994 - 2000 Ralf Baechle * Copyright (C) 1999, 2000 Silicon Graphics, Inc. */ #include <linux/cache.h> #include <linux/sched.h> #include <linux/mm.h> #include <linux/personality.h> #include <linux/smp.h> #include <linux/kernel.h> #include <linux/signal.h> #include <linux/errno.h> #include <linux/wait.h> #include <linux/ptrace.h> #include <linux/unistd.h> #include <linux/compiler.h> #include <linux/uaccess.h> #include <asm/abi.h> #include <asm/asm.h> #include <linux/bitops.h> #include <asm/cacheflush.h> #include <asm/fpu.h> #include <asm/sim.h> #include <asm/ucontext.h> #include <asm/cpu-features.h> #include <asm/war.h> #include "signal-common.h" /* * Horribly complicated - with the bloody RM9000 workarounds enabled * the signal trampolines is moving to the end of the structure so we can * increase the alignment without breaking software compatibility. */ #if ICACHE_REFILLS_WORKAROUND_WAR == 0 struct sigframe { u32 sf_ass[4]; /* argument save space for o32 */ u32 sf_code[2]; /* signal trampoline */ struct sigcontext sf_sc; sigset_t sf_mask; }; struct rt_sigframe { u32 rs_ass[4]; /* argument save space for o32 */ u32 rs_code[2]; /* signal trampoline */ struct siginfo rs_info; struct ucontext rs_uc; }; #else struct sigframe { u32 sf_ass[4]; /* argument save space for o32 */ u32 sf_pad[2]; struct sigcontext sf_sc; /* hw context */ sigset_t sf_mask; u32 sf_code[8] ____cacheline_aligned; /* signal trampoline */ }; struct rt_sigframe { u32 rs_ass[4]; /* argument save space for o32 */ u32 rs_pad[2]; struct siginfo rs_info; struct ucontext rs_uc; u32 rs_code[8] ____cacheline_aligned; /* signal trampoline */ }; #endif /* * Helper routines */ static int protected_save_fp_context(struct sigcontext __user *sc) { int err; while (1) { lock_fpu_owner(); own_fpu_inatomic(1); err = save_fp_context(sc); /* this might fail */ unlock_fpu_owner(); if (likely(!err)) break; /* touch the sigcontext and try again */ err = __put_user(0, &sc->sc_fpregs[0]) | __put_user(0, &sc->sc_fpregs[31]) | __put_user(0, &sc->sc_fpc_csr); if (err) break; /* really bad sigcontext */ } return err; } static int protected_restore_fp_context(struct sigcontext __user *sc) { int err, tmp; while (1) { lock_fpu_owner(); own_fpu_inatomic(0); err = restore_fp_context(sc); /* this might fail */ unlock_fpu_owner(); if (likely(!err)) break; /* touch the sigcontext and try again */ err = __get_user(tmp, &sc->sc_fpregs[0]) | __get_user(tmp, &sc->sc_fpregs[31]) | __get_user(tmp, &sc->sc_fpc_csr); if (err) break; /* really bad sigcontext */ } return err; } int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) { int err = 0; int i; unsigned int used_math; err |= __put_user(regs->cp0_epc, &sc->sc_pc); err |= __put_user(0, &sc->sc_regs[0]); for (i = 1; i < 32; i++) err |= __put_user(regs->regs[i], &sc->sc_regs[i]); #ifdef CONFIG_CPU_HAS_SMARTMIPS err |= __put_user(regs->acx, &sc->sc_acx); #endif err |= __put_user(regs->hi, &sc->sc_mdhi); err |= __put_user(regs->lo, &sc->sc_mdlo); if (cpu_has_dsp) { err |= __put_user(mfhi1(), &sc->sc_hi1); err |= __put_user(mflo1(), &sc->sc_lo1); err |= __put_user(mfhi2(), &sc->sc_hi2); err |= __put_user(mflo2(), &sc->sc_lo2); err |= __put_user(mfhi3(), &sc->sc_hi3); err |= __put_user(mflo3(), &sc->sc_lo3); err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp); } used_math = !!used_math(); err |= __put_user(used_math, &sc->sc_used_math); if (used_math) { /* * Save FPU state to signal context. Signal handler * will "inherit" current FPU state. */ err |= protected_save_fp_context(sc); } return err; } int fpcsr_pending(unsigned int __user *fpcsr) { int err, sig = 0; unsigned int csr, enabled; err = __get_user(csr, fpcsr); enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5); /* * If the signal handler set some FPU exceptions, clear it and * send SIGFPE. */ if (csr & enabled) { csr &= ~enabled; err |= __put_user(csr, fpcsr); sig = SIGFPE; } return err ?: sig; } static int check_and_restore_fp_context(struct sigcontext __user *sc) { int err, sig; err = sig = fpcsr_pending(&sc->sc_fpc_csr); if (err > 0) err = 0; err |= protected_restore_fp_context(sc); return err ?: sig; } int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) { unsigned int used_math; unsigned long treg; int err = 0; int i; /* Always make any pending restarted system calls return -EINTR */ current_thread_info()->restart_block.fn = do_no_restart_syscall; err |= __get_user(regs->cp0_epc, &sc->sc_pc); #ifdef CONFIG_CPU_HAS_SMARTMIPS err |= __get_user(regs->acx, &sc->sc_acx); #endif err |= __get_user(regs->hi, &sc->sc_mdhi); err |= __get_user(regs->lo, &sc->sc_mdlo); if (cpu_has_dsp) { err |= __get_user(treg, &sc->sc_hi1); mthi1(treg); err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg); err |= __get_user(treg, &sc->sc_hi2); mthi2(treg); err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg); err |= __get_user(treg, &sc->sc_hi3); mthi3(treg); err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg); err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK); } for (i = 1; i < 32; i++) err |= __get_user(regs->regs[i], &sc->sc_regs[i]); err |= __get_user(used_math, &sc->sc_used_math); conditional_used_math(used_math); if (used_math) { /* restore fpu context if we have used it before */ if (!err) err = check_and_restore_fp_context(sc); } else { /* signal handler may have used FPU. Give it up. */ lose_fpu(0); } return err; } void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size) { unsigned long sp; /* Default to using normal stack */ sp = regs->regs[29]; /* * FPU emulator may have it's own trampoline active just * above the user stack, 16-bytes before the next lowest * 16 byte boundary. Try to avoid trashing it. */ sp -= 32; /* This is the X/Open sanctioned signal stack switching. */ if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags (sp) == 0)) sp = current->sas_ss_sp + current->sas_ss_size; return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK)); } int install_sigtramp(unsigned int __user *tramp, unsigned int syscall) { int err; /* * Set up the return code ... * * li v0, __NR__foo_sigreturn * syscall */ err = __put_user(0x24020000 + syscall, tramp + 0); err |= __put_user(0x0000000c , tramp + 1); if (ICACHE_REFILLS_WORKAROUND_WAR) { err |= __put_user(0, tramp + 2); err |= __put_user(0, tramp + 3); err |= __put_user(0, tramp + 4); err |= __put_user(0, tramp + 5); err |= __put_user(0, tramp + 6); err |= __put_user(0, tramp + 7); } flush_cache_sigtramp((unsigned long) tramp); return err; } /* * Atomically swap in the new signal mask, and wait for a signal. */ #ifdef CONFIG_TRAD_SIGNALS asmlinkage int sys_sigsuspend(nabi_no_regargs struct pt_regs regs) { sigset_t newset; sigset_t __user *uset; uset = (sigset_t __user *) regs.regs[4]; if (copy_from_user(&newset, uset, sizeof(sigset_t))) return -EFAULT; sigdelsetmask(&newset, ~_BLOCKABLE); spin_lock_irq(¤t->sighand->siglock); current->saved_sigmask = current->blocked; current->blocked = newset; recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); current->state = TASK_INTERRUPTIBLE; schedule(); set_thread_flag(TIF_RESTORE_SIGMASK); return -ERESTARTNOHAND; } #endif asmlinkage int sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs) { sigset_t newset; sigset_t __user *unewset; size_t sigsetsize; /* XXX Don't preclude handling different sized sigset_t's. */ sigsetsize = regs.regs[5]; if (sigsetsize != sizeof(sigset_t)) return -EINVAL; unewset = (sigset_t __user *) regs.regs[4]; if (copy_from_user(&newset, unewset, sizeof(newset))) return -EFAULT; sigdelsetmask(&newset, ~_BLOCKABLE); spin_lock_irq(¤t->sighand->siglock); current->saved_sigmask = current->blocked; current->blocked = newset; recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); current->state = TASK_INTERRUPTIBLE; schedule(); set_thread_flag(TIF_RESTORE_SIGMASK); return -ERESTARTNOHAND; } #ifdef CONFIG_TRAD_SIGNALS asmlinkage int sys_sigaction(int sig, const struct sigaction __user *act, struct sigaction __user *oact) { struct k_sigaction new_ka, old_ka; int ret; int err = 0; if (act) { old_sigset_t mask; if (!access_ok(VERIFY_READ, act, sizeof(*act))) return -EFAULT; err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler); err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags); err |= __get_user(mask, &act->sa_mask.sig[0]); if (err) return -EFAULT; siginitset(&new_ka.sa.sa_mask, mask); } ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); if (!ret && oact) { if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact))) return -EFAULT; err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags); err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler); err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig); err |= __put_user(0, &oact->sa_mask.sig[1]); err |= __put_user(0, &oact->sa_mask.sig[2]); err |= __put_user(0, &oact->sa_mask.sig[3]); if (err) return -EFAULT; } return ret; } #endif asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs) { const stack_t __user *uss = (const stack_t __user *) regs.regs[4]; stack_t __user *uoss = (stack_t __user *) regs.regs[5]; unsigned long usp = regs.regs[29]; return do_sigaltstack(uss, uoss, usp); } #ifdef CONFIG_TRAD_SIGNALS asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs) { struct sigframe __user *frame; sigset_t blocked; int sig; frame = (struct sigframe __user *) regs.regs[29]; if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) goto badframe; if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked))) goto badframe; sigdelsetmask(&blocked, ~_BLOCKABLE); spin_lock_irq(¤t->sighand->siglock); current->blocked = blocked; recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); sig = restore_sigcontext(®s, &frame->sf_sc); if (sig < 0) goto badframe; else if (sig) force_sig(sig, current); /* * Don't let your children do this ... */ __asm__ __volatile__( "move\t$29, %0\n\t" "j\tsyscall_exit" :/* no outputs */ :"r" (®s)); /* Unreached */ badframe: force_sig(SIGSEGV, current); } #endif /* CONFIG_TRAD_SIGNALS */ asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs) { struct rt_sigframe __user *frame; sigset_t set; stack_t st; int sig; frame = (struct rt_sigframe __user *) regs.regs[29]; if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) goto badframe; if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set))) goto badframe; sigdelsetmask(&set, ~_BLOCKABLE); spin_lock_irq(¤t->sighand->siglock); current->blocked = set; recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); sig = restore_sigcontext(®s, &frame->rs_uc.uc_mcontext); if (sig < 0) goto badframe; else if (sig) force_sig(sig, current); if (__copy_from_user(&st, &frame->rs_uc.uc_stack, sizeof(st))) goto badframe; /* It is more difficult to avoid calling this function than to call it and ignore errors. */ do_sigaltstack((stack_t __user *)&st, NULL, regs.regs[29]); /* * Don't let your children do this ... */ __asm__ __volatile__( "move\t$29, %0\n\t" "j\tsyscall_exit" :/* no outputs */ :"r" (®s)); /* Unreached */ badframe: force_sig(SIGSEGV, current); } #ifdef CONFIG_TRAD_SIGNALS static int setup_frame(struct k_sigaction * ka, struct pt_regs *regs, int signr, sigset_t *set) { struct sigframe __user *frame; int err = 0; frame = get_sigframe(ka, regs, sizeof(*frame)); if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame))) goto give_sigsegv; err |= install_sigtramp(frame->sf_code, __NR_sigreturn); err |= setup_sigcontext(regs, &frame->sf_sc); err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set)); if (err) goto give_sigsegv; /* * Arguments to signal handler: * * a0 = signal number * a1 = 0 (should be cause) * a2 = pointer to struct sigcontext * * $25 and c0_epc point to the signal handler, $29 points to the * struct sigframe. */ regs->regs[ 4] = signr; regs->regs[ 5] = 0; regs->regs[ 6] = (unsigned long) &frame->sf_sc; regs->regs[29] = (unsigned long) frame; regs->regs[31] = (unsigned long) frame->sf_code; regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler; DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n", current->comm, current->pid, frame, regs->cp0_epc, regs->regs[31]); return 0; give_sigsegv: force_sigsegv(signr, current); return -EFAULT; } #endif static int setup_rt_frame(struct k_sigaction * ka, struct pt_regs *regs, int signr, sigset_t *set, siginfo_t *info) { struct rt_sigframe __user *frame; int err = 0; frame = get_sigframe(ka, regs, sizeof(*frame)); if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame))) goto give_sigsegv; err |= install_sigtramp(frame->rs_code, __NR_rt_sigreturn); /* Create siginfo. */ err |= copy_siginfo_to_user(&frame->rs_info, info); /* Create the ucontext. */ err |= __put_user(0, &frame->rs_uc.uc_flags); err |= __put_user(NULL, &frame->rs_uc.uc_link); err |= __put_user((void __user *)current->sas_ss_sp, &frame->rs_uc.uc_stack.ss_sp); err |= __put_user(sas_ss_flags(regs->regs[29]), &frame->rs_uc.uc_stack.ss_flags); err |= __put_user(current->sas_ss_size, &frame->rs_uc.uc_stack.ss_size); err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext); err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set)); if (err) goto give_sigsegv; /* * Arguments to signal handler: * * a0 = signal number * a1 = 0 (should be cause) * a2 = pointer to ucontext * * $25 and c0_epc point to the signal handler, $29 points to * the struct rt_sigframe. */ regs->regs[ 4] = signr; regs->regs[ 5] = (unsigned long) &frame->rs_info; regs->regs[ 6] = (unsigned long) &frame->rs_uc; regs->regs[29] = (unsigned long) frame; regs->regs[31] = (unsigned long) frame->rs_code; regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler; DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n", current->comm, current->pid, frame, regs->cp0_epc, regs->regs[31]); return 0; give_sigsegv: force_sigsegv(signr, current); return -EFAULT; } struct mips_abi mips_abi = { #ifdef CONFIG_TRAD_SIGNALS .setup_frame = setup_frame, #endif .setup_rt_frame = setup_rt_frame, .restart = __NR_restart_syscall }; static int handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs) { int ret; switch(regs->regs[0]) { case ERESTART_RESTARTBLOCK: case ERESTARTNOHAND: regs->regs[2] = EINTR; break; case ERESTARTSYS: if (!(ka->sa.sa_flags & SA_RESTART)) { regs->regs[2] = EINTR; break; } /* fallthrough */ case ERESTARTNOINTR: /* Userland will reload $v0. */ regs->regs[7] = regs->regs[26]; regs->cp0_epc -= 8; } regs->regs[0] = 0; /* Don't deal with this again. */ if (sig_uses_siginfo(ka)) ret = current->thread.abi->setup_rt_frame(ka, regs, sig, oldset, info); else ret = current->thread.abi->setup_frame(ka, regs, sig, oldset); 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 void do_signal(struct pt_regs *regs) { struct k_sigaction ka; sigset_t *oldset; siginfo_t info; int signr; /* * We want the common case to go fast, which is why we may in certain * cases get here from kernel mode. Just return without doing anything * if so. */ if (!user_mode(regs)) return; if (test_thread_flag(TIF_RESTORE_SIGMASK)) oldset = ¤t->saved_sigmask; else oldset = ¤t->blocked; signr = get_signal_to_deliver(&info, &ka, regs, NULL); if (signr > 0) { /* Whee! Actually deliver the signal. */ if (handle_signal(signr, &info, &ka, oldset, regs) == 0) { /* * A signal was successfully delivered; the saved * sigmask will have been stored in the signal frame, * and will be restored by sigreturn, so we can simply * clear the TIF_RESTORE_SIGMASK flag. */ if (test_thread_flag(TIF_RESTORE_SIGMASK)) clear_thread_flag(TIF_RESTORE_SIGMASK); } return; } /* * Who's code doesn't conform to the restartable syscall convention * dies here!!! The li instruction, a single machine instruction, * must directly be followed by the syscall instruction. */ if (regs->regs[0]) { if (regs->regs[2] == ERESTARTNOHAND || regs->regs[2] == ERESTARTSYS || regs->regs[2] == ERESTARTNOINTR) { regs->regs[7] = regs->regs[26]; regs->cp0_epc -= 8; } if (regs->regs[2] == ERESTART_RESTARTBLOCK) { regs->regs[2] = current->thread.abi->restart; regs->regs[7] = regs->regs[26]; regs->cp0_epc -= 4; } regs->regs[0] = 0; /* Don't deal with this again. */ } /* * If there's no signal to deliver, we just 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); } } /* * notification of userspace execution resumption * - triggered by the TIF_WORK_MASK flags */ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags) { /* deal with pending signal delivery */ if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK)) do_signal(regs); }