diff options
Diffstat (limited to 'arch/mips/kernel/signal.c')
| -rw-r--r-- | arch/mips/kernel/signal.c | 673 |
1 files changed, 673 insertions, 0 deletions
diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c new file mode 100644 index 000000000..6a28c792d --- /dev/null +++ b/arch/mips/kernel/signal.c @@ -0,0 +1,673 @@ +/* + * 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. + * Copyright (C) 2014, Imagination Technologies Ltd. + */ +#include <linux/cache.h> +#include <linux/context_tracking.h> +#include <linux/irqflags.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/syscalls.h> +#include <linux/uaccess.h> +#include <linux/tracehook.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 <asm/vdso.h> +#include <asm/dsp.h> +#include <asm/inst.h> + +#include "signal-common.h" + +static int (*save_fp_context)(struct sigcontext __user *sc); +static int (*restore_fp_context)(struct sigcontext __user *sc); + +extern asmlinkage int _save_fp_context(struct sigcontext __user *sc); +extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc); + +struct sigframe { + u32 sf_ass[4]; /* argument save space for o32 */ + u32 sf_pad[2]; /* Was: signal trampoline */ + struct sigcontext sf_sc; + sigset_t sf_mask; +}; + +struct rt_sigframe { + u32 rs_ass[4]; /* argument save space for o32 */ + u32 rs_pad[2]; /* Was: signal trampoline */ + struct siginfo rs_info; + struct ucontext rs_uc; +}; + +/* + * Thread saved context copy to/from a signal context presumed to be on the + * user stack, and therefore accessed with appropriate macros from uaccess.h. + */ +static int copy_fp_to_sigcontext(struct sigcontext __user *sc) +{ + int i; + int err = 0; + + for (i = 0; i < NUM_FPU_REGS; i++) { + err |= + __put_user(get_fpr64(¤t->thread.fpu.fpr[i], 0), + &sc->sc_fpregs[i]); + } + err |= __put_user(current->thread.fpu.fcr31, &sc->sc_fpc_csr); + + return err; +} + +static int copy_fp_from_sigcontext(struct sigcontext __user *sc) +{ + int i; + int err = 0; + u64 fpr_val; + + for (i = 0; i < NUM_FPU_REGS; i++) { + err |= __get_user(fpr_val, &sc->sc_fpregs[i]); + set_fpr64(¤t->thread.fpu.fpr[i], 0, fpr_val); + } + err |= __get_user(current->thread.fpu.fcr31, &sc->sc_fpc_csr); + + return err; +} + +/* + * Helper routines + */ +static int protected_save_fp_context(struct sigcontext __user *sc) +{ + int err; +#ifndef CONFIG_EVA + while (1) { + lock_fpu_owner(); + if (is_fpu_owner()) { + err = save_fp_context(sc); + unlock_fpu_owner(); + } else { + unlock_fpu_owner(); + err = copy_fp_to_sigcontext(sc); + } + 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 */ + } +#else + /* + * EVA does not have FPU EVA instructions so saving fpu context directly + * does not work. + */ + lose_fpu(1); + err = save_fp_context(sc); /* this might fail */ +#endif + return err; +} + +static int protected_restore_fp_context(struct sigcontext __user *sc) +{ + int err, tmp __maybe_unused; +#ifndef CONFIG_EVA + while (1) { + lock_fpu_owner(); + if (is_fpu_owner()) { + err = restore_fp_context(sc); + unlock_fpu_owner(); + } else { + unlock_fpu_owner(); + err = copy_fp_from_sigcontext(sc); + } + 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 */ + } +#else + /* + * EVA does not have FPU EVA instructions so restoring fpu context + * directly does not work. + */ + lose_fpu(0); + err = restore_fp_context(sc); /* this might fail */ +#endif + 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->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 ksignal *ksig, 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; + + sp = sigsp(sp, ksig); + + return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK)); +} + +/* + * Atomically swap in the new signal mask, and wait for a signal. + */ + +#ifdef CONFIG_TRAD_SIGNALS +SYSCALL_DEFINE1(sigsuspend, sigset_t __user *, uset) +{ + return sys_rt_sigsuspend(uset, sizeof(sigset_t)); +} +#endif + +#ifdef CONFIG_TRAD_SIGNALS +SYSCALL_DEFINE3(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 + +#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; + + set_current_blocked(&blocked); + + 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; + 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; + + set_current_blocked(&set); + + sig = restore_sigcontext(®s, &frame->rs_uc.uc_mcontext); + if (sig < 0) + goto badframe; + else if (sig) + force_sig(sig, current); + + if (restore_altstack(&frame->rs_uc.uc_stack)) + goto badframe; + + /* + * 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(void *sig_return, struct ksignal *ksig, + struct pt_regs *regs, sigset_t *set) +{ + struct sigframe __user *frame; + int err = 0; + + frame = get_sigframe(ksig, regs, sizeof(*frame)); + if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame))) + return -EFAULT; + + err |= setup_sigcontext(regs, &frame->sf_sc); + err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set)); + if (err) + return -EFAULT; + + /* + * 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] = ksig->sig; + regs->regs[ 5] = 0; + regs->regs[ 6] = (unsigned long) &frame->sf_sc; + regs->regs[29] = (unsigned long) frame; + regs->regs[31] = (unsigned long) sig_return; + regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->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; +} +#endif + +static int setup_rt_frame(void *sig_return, struct ksignal *ksig, + struct pt_regs *regs, sigset_t *set) +{ + struct rt_sigframe __user *frame; + int err = 0; + + frame = get_sigframe(ksig, regs, sizeof(*frame)); + if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame))) + return -EFAULT; + + /* Create siginfo. */ + err |= copy_siginfo_to_user(&frame->rs_info, &ksig->info); + + /* Create the ucontext. */ + err |= __put_user(0, &frame->rs_uc.uc_flags); + err |= __put_user(NULL, &frame->rs_uc.uc_link); + err |= __save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]); + err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext); + err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set)); + + if (err) + return -EFAULT; + + /* + * 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] = ksig->sig; + 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) sig_return; + regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->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; +} + +struct mips_abi mips_abi = { +#ifdef CONFIG_TRAD_SIGNALS + .setup_frame = setup_frame, + .signal_return_offset = offsetof(struct mips_vdso, signal_trampoline), +#endif + .setup_rt_frame = setup_rt_frame, + .rt_signal_return_offset = + offsetof(struct mips_vdso, rt_signal_trampoline), + .restart = __NR_restart_syscall +}; + +static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) +{ + sigset_t *oldset = sigmask_to_save(); + int ret; + struct mips_abi *abi = current->thread.abi; +#ifdef CONFIG_CPU_MICROMIPS + void *vdso; + unsigned long tmp = (unsigned long)current->mm->context.vdso; + + set_isa16_mode(tmp); + vdso = (void *)tmp; +#else + void *vdso = current->mm->context.vdso; +#endif + + if (regs->regs[0]) { + switch(regs->regs[2]) { + case ERESTART_RESTARTBLOCK: + case ERESTARTNOHAND: + regs->regs[2] = EINTR; + break; + case ERESTARTSYS: + if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { + regs->regs[2] = EINTR; + break; + } + /* fallthrough */ + case ERESTARTNOINTR: + regs->regs[7] = regs->regs[26]; + regs->regs[2] = regs->regs[0]; + regs->cp0_epc -= 4; + } + + regs->regs[0] = 0; /* Don't deal with this again. */ + } + + if (sig_uses_siginfo(&ksig->ka)) + ret = abi->setup_rt_frame(vdso + abi->rt_signal_return_offset, + ksig, regs, oldset); + else + ret = abi->setup_frame(vdso + abi->signal_return_offset, ksig, + regs, oldset); + + signal_setup_done(ret, ksig, 0); +} + +static void do_signal(struct pt_regs *regs) +{ + struct ksignal ksig; + + if (get_signal(&ksig)) { + /* Whee! Actually deliver the signal. */ + handle_signal(&ksig, regs); + return; + } + + if (regs->regs[0]) { + switch (regs->regs[2]) { + case ERESTARTNOHAND: + case ERESTARTSYS: + case ERESTARTNOINTR: + regs->regs[2] = regs->regs[0]; + regs->regs[7] = regs->regs[26]; + regs->cp0_epc -= 4; + break; + + case ERESTART_RESTARTBLOCK: + regs->regs[2] = current->thread.abi->restart; + regs->regs[7] = regs->regs[26]; + regs->cp0_epc -= 4; + break; + } + regs->regs[0] = 0; /* Don't deal with this again. */ + } + + /* + * If there's no signal to deliver, we just put the saved sigmask + * back + */ + restore_saved_sigmask(); +} + +/* + * 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) +{ + local_irq_enable(); + + user_exit(); + + /* deal with pending signal delivery */ + if (thread_info_flags & _TIF_SIGPENDING) + do_signal(regs); + + if (thread_info_flags & _TIF_NOTIFY_RESUME) { + clear_thread_flag(TIF_NOTIFY_RESUME); + tracehook_notify_resume(regs); + } + + user_enter(); +} + +#ifdef CONFIG_SMP +#ifndef CONFIG_EVA +static int smp_save_fp_context(struct sigcontext __user *sc) +{ + return raw_cpu_has_fpu + ? _save_fp_context(sc) + : copy_fp_to_sigcontext(sc); +} + +static int smp_restore_fp_context(struct sigcontext __user *sc) +{ + return raw_cpu_has_fpu + ? _restore_fp_context(sc) + : copy_fp_from_sigcontext(sc); +} +#endif /* CONFIG_EVA */ +#endif + +static int signal_setup(void) +{ +#ifndef CONFIG_EVA +#ifdef CONFIG_SMP + /* For now just do the cpu_has_fpu check when the functions are invoked */ + save_fp_context = smp_save_fp_context; + restore_fp_context = smp_restore_fp_context; +#else + if (cpu_has_fpu) { + save_fp_context = _save_fp_context; + restore_fp_context = _restore_fp_context; + } else { + save_fp_context = copy_fp_to_sigcontext; + restore_fp_context = copy_fp_from_sigcontext; + } +#endif /* CONFIG_SMP */ +#else + save_fp_context = copy_fp_to_sigcontext; + restore_fp_context = copy_fp_from_sigcontext; +#endif + + return 0; +} + +arch_initcall(signal_setup); |