diff options
Diffstat (limited to 'arch/alpha/kernel/signal.c')
| -rw-r--r-- | arch/alpha/kernel/signal.c | 540 |
1 files changed, 540 insertions, 0 deletions
diff --git a/arch/alpha/kernel/signal.c b/arch/alpha/kernel/signal.c new file mode 100644 index 000000000..6f47f256f --- /dev/null +++ b/arch/alpha/kernel/signal.c @@ -0,0 +1,540 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/arch/alpha/kernel/signal.c + * + * Copyright (C) 1995 Linus Torvalds + * + * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson + */ + +#include <linux/sched/signal.h> +#include <linux/sched/task_stack.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/mm.h> +#include <linux/smp.h> +#include <linux/stddef.h> +#include <linux/tty.h> +#include <linux/binfmts.h> +#include <linux/bitops.h> +#include <linux/syscalls.h> +#include <linux/resume_user_mode.h> + +#include <linux/uaccess.h> +#include <asm/sigcontext.h> +#include <asm/ucontext.h> + +#include "proto.h" + + +#define DEBUG_SIG 0 + +#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) + +asmlinkage void ret_from_sys_call(void); + +/* + * The OSF/1 sigprocmask calling sequence is different from the + * C sigprocmask() sequence.. + */ +SYSCALL_DEFINE2(osf_sigprocmask, int, how, unsigned long, newmask) +{ + sigset_t oldmask; + sigset_t mask; + unsigned long res; + + siginitset(&mask, newmask & _BLOCKABLE); + res = sigprocmask(how, &mask, &oldmask); + if (!res) { + force_successful_syscall_return(); + res = oldmask.sig[0]; + } + return res; +} + +SYSCALL_DEFINE3(osf_sigaction, int, sig, + const struct osf_sigaction __user *, act, + struct osf_sigaction __user *, oact) +{ + struct k_sigaction new_ka, old_ka; + int ret; + + if (act) { + old_sigset_t mask; + if (!access_ok(act, sizeof(*act)) || + __get_user(new_ka.sa.sa_handler, &act->sa_handler) || + __get_user(new_ka.sa.sa_flags, &act->sa_flags) || + __get_user(mask, &act->sa_mask)) + return -EFAULT; + siginitset(&new_ka.sa.sa_mask, mask); + new_ka.ka_restorer = NULL; + } + + ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); + + if (!ret && oact) { + if (!access_ok(oact, sizeof(*oact)) || + __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || + __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || + __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) + return -EFAULT; + } + + return ret; +} + +SYSCALL_DEFINE5(rt_sigaction, int, sig, const struct sigaction __user *, act, + struct sigaction __user *, oact, + size_t, sigsetsize, void __user *, restorer) +{ + struct k_sigaction new_ka, old_ka; + int ret; + + /* XXX: Don't preclude handling different sized sigset_t's. */ + if (sigsetsize != sizeof(sigset_t)) + return -EINVAL; + + if (act) { + new_ka.ka_restorer = restorer; + if (copy_from_user(&new_ka.sa, act, sizeof(*act))) + return -EFAULT; + } + + ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); + + if (!ret && oact) { + if (copy_to_user(oact, &old_ka.sa, sizeof(*oact))) + return -EFAULT; + } + + return ret; +} + +/* + * Do a signal return; undo the signal stack. + */ + +#if _NSIG_WORDS > 1 +# error "Non SA_SIGINFO frame needs rearranging" +#endif + +struct sigframe +{ + struct sigcontext sc; + unsigned int retcode[3]; +}; + +struct rt_sigframe +{ + struct siginfo info; + struct ucontext uc; + unsigned int retcode[3]; +}; + +/* If this changes, userland unwinders that Know Things about our signal + frame will break. Do not undertake lightly. It also implies an ABI + change wrt the size of siginfo_t, which may cause some pain. */ +extern char compile_time_assert + [offsetof(struct rt_sigframe, uc.uc_mcontext) == 176 ? 1 : -1]; + +#define INSN_MOV_R30_R16 0x47fe0410 +#define INSN_LDI_R0 0x201f0000 +#define INSN_CALLSYS 0x00000083 + +static long +restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs) +{ + unsigned long usp; + struct switch_stack *sw = (struct switch_stack *)regs - 1; + long i, err = __get_user(regs->pc, &sc->sc_pc); + + current->restart_block.fn = do_no_restart_syscall; + + sw->r26 = (unsigned long) ret_from_sys_call; + + err |= __get_user(regs->r0, sc->sc_regs+0); + err |= __get_user(regs->r1, sc->sc_regs+1); + err |= __get_user(regs->r2, sc->sc_regs+2); + err |= __get_user(regs->r3, sc->sc_regs+3); + err |= __get_user(regs->r4, sc->sc_regs+4); + err |= __get_user(regs->r5, sc->sc_regs+5); + err |= __get_user(regs->r6, sc->sc_regs+6); + err |= __get_user(regs->r7, sc->sc_regs+7); + err |= __get_user(regs->r8, sc->sc_regs+8); + err |= __get_user(sw->r9, sc->sc_regs+9); + err |= __get_user(sw->r10, sc->sc_regs+10); + err |= __get_user(sw->r11, sc->sc_regs+11); + err |= __get_user(sw->r12, sc->sc_regs+12); + err |= __get_user(sw->r13, sc->sc_regs+13); + err |= __get_user(sw->r14, sc->sc_regs+14); + err |= __get_user(sw->r15, sc->sc_regs+15); + err |= __get_user(regs->r16, sc->sc_regs+16); + err |= __get_user(regs->r17, sc->sc_regs+17); + err |= __get_user(regs->r18, sc->sc_regs+18); + err |= __get_user(regs->r19, sc->sc_regs+19); + err |= __get_user(regs->r20, sc->sc_regs+20); + err |= __get_user(regs->r21, sc->sc_regs+21); + err |= __get_user(regs->r22, sc->sc_regs+22); + err |= __get_user(regs->r23, sc->sc_regs+23); + err |= __get_user(regs->r24, sc->sc_regs+24); + err |= __get_user(regs->r25, sc->sc_regs+25); + err |= __get_user(regs->r26, sc->sc_regs+26); + err |= __get_user(regs->r27, sc->sc_regs+27); + err |= __get_user(regs->r28, sc->sc_regs+28); + err |= __get_user(regs->gp, sc->sc_regs+29); + err |= __get_user(usp, sc->sc_regs+30); + wrusp(usp); + + for (i = 0; i < 31; i++) + err |= __get_user(sw->fp[i], sc->sc_fpregs+i); + err |= __get_user(sw->fp[31], &sc->sc_fpcr); + + return err; +} + +/* Note that this syscall is also used by setcontext(3) to install + a given sigcontext. This because it's impossible to set *all* + registers and transfer control from userland. */ + +asmlinkage void +do_sigreturn(struct sigcontext __user *sc) +{ + struct pt_regs *regs = current_pt_regs(); + sigset_t set; + + /* Verify that it's a good sigcontext before using it */ + if (!access_ok(sc, sizeof(*sc))) + goto give_sigsegv; + if (__get_user(set.sig[0], &sc->sc_mask)) + goto give_sigsegv; + + set_current_blocked(&set); + + if (restore_sigcontext(sc, regs)) + goto give_sigsegv; + + /* Send SIGTRAP if we're single-stepping: */ + if (ptrace_cancel_bpt (current)) { + send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *) regs->pc, + current); + } + return; + +give_sigsegv: + force_sig(SIGSEGV); +} + +asmlinkage void +do_rt_sigreturn(struct rt_sigframe __user *frame) +{ + struct pt_regs *regs = current_pt_regs(); + sigset_t set; + + /* Verify that it's a good ucontext_t before using it */ + if (!access_ok(&frame->uc, sizeof(frame->uc))) + goto give_sigsegv; + if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) + goto give_sigsegv; + + set_current_blocked(&set); + + if (restore_sigcontext(&frame->uc.uc_mcontext, regs)) + goto give_sigsegv; + + /* Send SIGTRAP if we're single-stepping: */ + if (ptrace_cancel_bpt (current)) { + send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *) regs->pc, + current); + } + return; + +give_sigsegv: + force_sig(SIGSEGV); +} + + +/* + * Set up a signal frame. + */ + +static inline void __user * +get_sigframe(struct ksignal *ksig, unsigned long sp, size_t frame_size) +{ + return (void __user *)((sigsp(sp, ksig) - frame_size) & -32ul); +} + +static long +setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, + unsigned long mask, unsigned long sp) +{ + struct switch_stack *sw = (struct switch_stack *)regs - 1; + long i, err = 0; + + err |= __put_user(on_sig_stack((unsigned long)sc), &sc->sc_onstack); + err |= __put_user(mask, &sc->sc_mask); + err |= __put_user(regs->pc, &sc->sc_pc); + err |= __put_user(8, &sc->sc_ps); + + err |= __put_user(regs->r0 , sc->sc_regs+0); + err |= __put_user(regs->r1 , sc->sc_regs+1); + err |= __put_user(regs->r2 , sc->sc_regs+2); + err |= __put_user(regs->r3 , sc->sc_regs+3); + err |= __put_user(regs->r4 , sc->sc_regs+4); + err |= __put_user(regs->r5 , sc->sc_regs+5); + err |= __put_user(regs->r6 , sc->sc_regs+6); + err |= __put_user(regs->r7 , sc->sc_regs+7); + err |= __put_user(regs->r8 , sc->sc_regs+8); + err |= __put_user(sw->r9 , sc->sc_regs+9); + err |= __put_user(sw->r10 , sc->sc_regs+10); + err |= __put_user(sw->r11 , sc->sc_regs+11); + err |= __put_user(sw->r12 , sc->sc_regs+12); + err |= __put_user(sw->r13 , sc->sc_regs+13); + err |= __put_user(sw->r14 , sc->sc_regs+14); + err |= __put_user(sw->r15 , sc->sc_regs+15); + err |= __put_user(regs->r16, sc->sc_regs+16); + err |= __put_user(regs->r17, sc->sc_regs+17); + err |= __put_user(regs->r18, sc->sc_regs+18); + err |= __put_user(regs->r19, sc->sc_regs+19); + err |= __put_user(regs->r20, sc->sc_regs+20); + err |= __put_user(regs->r21, sc->sc_regs+21); + err |= __put_user(regs->r22, sc->sc_regs+22); + err |= __put_user(regs->r23, sc->sc_regs+23); + err |= __put_user(regs->r24, sc->sc_regs+24); + err |= __put_user(regs->r25, sc->sc_regs+25); + err |= __put_user(regs->r26, sc->sc_regs+26); + err |= __put_user(regs->r27, sc->sc_regs+27); + err |= __put_user(regs->r28, sc->sc_regs+28); + err |= __put_user(regs->gp , sc->sc_regs+29); + err |= __put_user(sp, sc->sc_regs+30); + err |= __put_user(0, sc->sc_regs+31); + + for (i = 0; i < 31; i++) + err |= __put_user(sw->fp[i], sc->sc_fpregs+i); + err |= __put_user(0, sc->sc_fpregs+31); + err |= __put_user(sw->fp[31], &sc->sc_fpcr); + + err |= __put_user(regs->trap_a0, &sc->sc_traparg_a0); + err |= __put_user(regs->trap_a1, &sc->sc_traparg_a1); + err |= __put_user(regs->trap_a2, &sc->sc_traparg_a2); + + return err; +} + +static int +setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) +{ + unsigned long oldsp, r26, err = 0; + struct sigframe __user *frame; + + oldsp = rdusp(); + frame = get_sigframe(ksig, oldsp, sizeof(*frame)); + if (!access_ok(frame, sizeof(*frame))) + return -EFAULT; + + err |= setup_sigcontext(&frame->sc, regs, set->sig[0], oldsp); + if (err) + return -EFAULT; + + /* Set up to return from userspace. If provided, use a stub + already in userspace. */ + r26 = (unsigned long) ksig->ka.ka_restorer; + if (!r26) { + err |= __put_user(INSN_MOV_R30_R16, frame->retcode+0); + err |= __put_user(INSN_LDI_R0+__NR_sigreturn, frame->retcode+1); + err |= __put_user(INSN_CALLSYS, frame->retcode+2); + imb(); + r26 = (unsigned long) frame->retcode; + } + + /* Check that everything was written properly. */ + if (err) + return err; + + /* "Return" to the handler */ + regs->r26 = r26; + regs->r27 = regs->pc = (unsigned long) ksig->ka.sa.sa_handler; + regs->r16 = ksig->sig; /* a0: signal number */ + regs->r17 = 0; /* a1: exception code */ + regs->r18 = (unsigned long) &frame->sc; /* a2: sigcontext pointer */ + wrusp((unsigned long) frame); + +#if DEBUG_SIG + printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n", + current->comm, current->pid, frame, regs->pc, regs->r26); +#endif + return 0; +} + +static int +setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) +{ + unsigned long oldsp, r26, err = 0; + struct rt_sigframe __user *frame; + + oldsp = rdusp(); + frame = get_sigframe(ksig, oldsp, sizeof(*frame)); + if (!access_ok(frame, sizeof(*frame))) + return -EFAULT; + + err |= copy_siginfo_to_user(&frame->info, &ksig->info); + + /* Create the ucontext. */ + err |= __put_user(0, &frame->uc.uc_flags); + err |= __put_user(0, &frame->uc.uc_link); + err |= __put_user(set->sig[0], &frame->uc.uc_osf_sigmask); + err |= __save_altstack(&frame->uc.uc_stack, oldsp); + err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, + set->sig[0], oldsp); + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); + if (err) + return -EFAULT; + + /* Set up to return from userspace. If provided, use a stub + already in userspace. */ + r26 = (unsigned long) ksig->ka.ka_restorer; + if (!r26) { + err |= __put_user(INSN_MOV_R30_R16, frame->retcode+0); + err |= __put_user(INSN_LDI_R0+__NR_rt_sigreturn, + frame->retcode+1); + err |= __put_user(INSN_CALLSYS, frame->retcode+2); + imb(); + r26 = (unsigned long) frame->retcode; + } + + if (err) + return -EFAULT; + + /* "Return" to the handler */ + regs->r26 = r26; + regs->r27 = regs->pc = (unsigned long) ksig->ka.sa.sa_handler; + regs->r16 = ksig->sig; /* a0: signal number */ + regs->r17 = (unsigned long) &frame->info; /* a1: siginfo pointer */ + regs->r18 = (unsigned long) &frame->uc; /* a2: ucontext pointer */ + wrusp((unsigned long) frame); + +#if DEBUG_SIG + printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n", + current->comm, current->pid, frame, regs->pc, regs->r26); +#endif + + return 0; +} + + +/* + * OK, we're invoking a handler. + */ +static inline void +handle_signal(struct ksignal *ksig, struct pt_regs *regs) +{ + sigset_t *oldset = sigmask_to_save(); + int ret; + + if (ksig->ka.sa.sa_flags & SA_SIGINFO) + ret = setup_rt_frame(ksig, oldset, regs); + else + ret = setup_frame(ksig, oldset, regs); + + signal_setup_done(ret, ksig, 0); +} + +static inline void +syscall_restart(unsigned long r0, unsigned long r19, + struct pt_regs *regs, struct k_sigaction *ka) +{ + switch (regs->r0) { + case ERESTARTSYS: + if (!(ka->sa.sa_flags & SA_RESTART)) { + case ERESTARTNOHAND: + regs->r0 = EINTR; + break; + } + fallthrough; + case ERESTARTNOINTR: + regs->r0 = r0; /* reset v0 and a3 and replay syscall */ + regs->r19 = r19; + regs->pc -= 4; + break; + case ERESTART_RESTARTBLOCK: + regs->r0 = EINTR; + 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. + * + * Note that we go through the signals twice: once to check the signals that + * the kernel can handle, and then we build all the user-level signal handling + * stack-frames in one go after that. + * + * "r0" and "r19" are the registers we need to restore for system call + * restart. "r0" is also used as an indicator whether we can restart at + * all (if we get here from anything but a syscall return, it will be 0) + */ +static void +do_signal(struct pt_regs *regs, unsigned long r0, unsigned long r19) +{ + unsigned long single_stepping = ptrace_cancel_bpt(current); + struct ksignal ksig; + + /* This lets the debugger run, ... */ + if (get_signal(&ksig)) { + /* ... so re-check the single stepping. */ + single_stepping |= ptrace_cancel_bpt(current); + /* Whee! Actually deliver the signal. */ + if (r0) + syscall_restart(r0, r19, regs, &ksig.ka); + handle_signal(&ksig, regs); + } else { + single_stepping |= ptrace_cancel_bpt(current); + if (r0) { + switch (regs->r0) { + case ERESTARTNOHAND: + case ERESTARTSYS: + case ERESTARTNOINTR: + /* Reset v0 and a3 and replay syscall. */ + regs->r0 = r0; + regs->r19 = r19; + regs->pc -= 4; + break; + case ERESTART_RESTARTBLOCK: + /* Set v0 to the restart_syscall and replay */ + regs->r0 = __NR_restart_syscall; + regs->pc -= 4; + break; + } + } + restore_saved_sigmask(); + } + if (single_stepping) + ptrace_set_bpt(current); /* re-set breakpoint */ +} + +void +do_work_pending(struct pt_regs *regs, unsigned long thread_flags, + unsigned long r0, unsigned long r19) +{ + do { + if (thread_flags & _TIF_NEED_RESCHED) { + schedule(); + } else { + local_irq_enable(); + if (thread_flags & (_TIF_SIGPENDING|_TIF_NOTIFY_SIGNAL)) { + do_signal(regs, r0, r19); + r0 = 0; + } else { + resume_user_mode_work(regs); + } + } + local_irq_disable(); + thread_flags = read_thread_flags(); + } while (thread_flags & _TIF_WORK_MASK); +} |