| // 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/tracehook.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(VERIFY_READ, 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(VERIFY_WRITE, 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(VERIFY_READ, 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, 0, |
| current); |
| } |
| return; |
| |
| give_sigsegv: |
| force_sig(SIGSEGV, current); |
| } |
| |
| 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(VERIFY_READ, &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, 0, |
| current); |
| } |
| return; |
| |
| give_sigsegv: |
| force_sig(SIGSEGV, current); |
| } |
| |
| |
| /* |
| * 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(VERIFY_WRITE, 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(VERIFY_WRITE, 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) { |
| do_signal(regs, r0, r19); |
| r0 = 0; |
| } else { |
| clear_thread_flag(TIF_NOTIFY_RESUME); |
| tracehook_notify_resume(regs); |
| } |
| } |
| local_irq_disable(); |
| thread_flags = current_thread_info()->flags; |
| } while (thread_flags & _TIF_WORK_MASK); |
| } |