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267 lines
6.2 KiB
267 lines
6.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include <linux/signal.h> |
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#include <linux/uaccess.h> |
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#include <linux/syscalls.h> |
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#include <linux/tracehook.h> |
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#include <asm/traps.h> |
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#include <asm/ucontext.h> |
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#include <asm/vdso.h> |
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#include <abi/regdef.h> |
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#ifdef CONFIG_CPU_HAS_FPU |
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#include <abi/fpu.h> |
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static int restore_fpu_state(struct sigcontext __user *sc) |
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{ |
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int err = 0; |
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struct user_fp user_fp; |
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err = __copy_from_user(&user_fp, &sc->sc_user_fp, sizeof(user_fp)); |
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restore_from_user_fp(&user_fp); |
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return err; |
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} |
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static int save_fpu_state(struct sigcontext __user *sc) |
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{ |
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struct user_fp user_fp; |
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save_to_user_fp(&user_fp); |
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return __copy_to_user(&sc->sc_user_fp, &user_fp, sizeof(user_fp)); |
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} |
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#else |
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#define restore_fpu_state(sigcontext) (0) |
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#define save_fpu_state(sigcontext) (0) |
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#endif |
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struct rt_sigframe { |
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/* |
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* pad[3] is compatible with the same struct defined in |
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* gcc/libgcc/config/csky/linux-unwind.h |
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*/ |
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int pad[3]; |
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struct siginfo info; |
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struct ucontext uc; |
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}; |
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static long restore_sigcontext(struct pt_regs *regs, |
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struct sigcontext __user *sc) |
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{ |
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int err = 0; |
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/* sc_pt_regs is structured the same as the start of pt_regs */ |
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err |= __copy_from_user(regs, &sc->sc_pt_regs, sizeof(struct pt_regs)); |
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/* Restore the floating-point state. */ |
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err |= restore_fpu_state(sc); |
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return err; |
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} |
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SYSCALL_DEFINE0(rt_sigreturn) |
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{ |
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struct pt_regs *regs = current_pt_regs(); |
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struct rt_sigframe __user *frame; |
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sigset_t set; |
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/* Always make any pending restarted system calls return -EINTR */ |
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current->restart_block.fn = do_no_restart_syscall; |
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frame = (struct rt_sigframe __user *)regs->usp; |
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if (!access_ok(frame, sizeof(*frame))) |
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goto badframe; |
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if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) |
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goto badframe; |
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set_current_blocked(&set); |
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if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) |
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goto badframe; |
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if (restore_altstack(&frame->uc.uc_stack)) |
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goto badframe; |
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return regs->a0; |
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badframe: |
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force_sig(SIGSEGV); |
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return 0; |
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} |
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static int setup_sigcontext(struct rt_sigframe __user *frame, |
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struct pt_regs *regs) |
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{ |
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struct sigcontext __user *sc = &frame->uc.uc_mcontext; |
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int err = 0; |
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err |= __copy_to_user(&sc->sc_pt_regs, regs, sizeof(struct pt_regs)); |
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err |= save_fpu_state(sc); |
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return err; |
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} |
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static inline void __user *get_sigframe(struct ksignal *ksig, |
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struct pt_regs *regs, size_t framesize) |
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{ |
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unsigned long sp; |
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/* Default to using normal stack */ |
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sp = regs->usp; |
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/* |
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* If we are on the alternate signal stack and would overflow it, don't. |
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* Return an always-bogus address instead so we will die with SIGSEGV. |
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*/ |
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if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize))) |
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return (void __user __force *)(-1UL); |
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/* This is the X/Open sanctioned signal stack switching. */ |
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sp = sigsp(sp, ksig) - framesize; |
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/* Align the stack frame. */ |
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sp &= -8UL; |
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return (void __user *)sp; |
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} |
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static int |
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setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) |
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{ |
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struct rt_sigframe *frame; |
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int err = 0; |
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frame = get_sigframe(ksig, regs, sizeof(*frame)); |
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if (!access_ok(frame, sizeof(*frame))) |
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return -EFAULT; |
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err |= copy_siginfo_to_user(&frame->info, &ksig->info); |
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/* Create the ucontext. */ |
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err |= __put_user(0, &frame->uc.uc_flags); |
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err |= __put_user(NULL, &frame->uc.uc_link); |
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err |= __save_altstack(&frame->uc.uc_stack, regs->usp); |
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err |= setup_sigcontext(frame, regs); |
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err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); |
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if (err) |
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return -EFAULT; |
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/* Set up to return from userspace. */ |
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regs->lr = (unsigned long)VDSO_SYMBOL( |
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current->mm->context.vdso, rt_sigreturn); |
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/* |
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* Set up registers for signal handler. |
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* Registers that we don't modify keep the value they had from |
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* user-space at the time we took the signal. |
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* We always pass siginfo and mcontext, regardless of SA_SIGINFO, |
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* since some things rely on this (e.g. glibc's debug/segfault.c). |
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*/ |
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regs->pc = (unsigned long)ksig->ka.sa.sa_handler; |
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regs->usp = (unsigned long)frame; |
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regs->a0 = ksig->sig; /* a0: signal number */ |
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regs->a1 = (unsigned long)(&(frame->info)); /* a1: siginfo pointer */ |
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regs->a2 = (unsigned long)(&(frame->uc)); /* a2: ucontext pointer */ |
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return 0; |
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} |
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static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) |
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{ |
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sigset_t *oldset = sigmask_to_save(); |
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int ret; |
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rseq_signal_deliver(ksig, regs); |
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/* Are we from a system call? */ |
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if (in_syscall(regs)) { |
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/* Avoid additional syscall restarting via ret_from_exception */ |
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forget_syscall(regs); |
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/* If so, check system call restarting.. */ |
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switch (regs->a0) { |
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case -ERESTART_RESTARTBLOCK: |
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case -ERESTARTNOHAND: |
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regs->a0 = -EINTR; |
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break; |
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case -ERESTARTSYS: |
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if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { |
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regs->a0 = -EINTR; |
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break; |
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} |
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fallthrough; |
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case -ERESTARTNOINTR: |
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regs->a0 = regs->orig_a0; |
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regs->pc -= TRAP0_SIZE; |
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break; |
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} |
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} |
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/* Set up the stack frame */ |
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ret = setup_rt_frame(ksig, oldset, regs); |
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signal_setup_done(ret, ksig, 0); |
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} |
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static void do_signal(struct pt_regs *regs) |
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{ |
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struct ksignal ksig; |
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if (get_signal(&ksig)) { |
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/* Actually deliver the signal */ |
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handle_signal(&ksig, regs); |
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return; |
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} |
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/* Did we come from a system call? */ |
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if (in_syscall(regs)) { |
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/* Avoid additional syscall restarting via ret_from_exception */ |
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forget_syscall(regs); |
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/* Restart the system call - no handlers present */ |
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switch (regs->a0) { |
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case -ERESTARTNOHAND: |
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case -ERESTARTSYS: |
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case -ERESTARTNOINTR: |
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regs->a0 = regs->orig_a0; |
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regs->pc -= TRAP0_SIZE; |
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break; |
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case -ERESTART_RESTARTBLOCK: |
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regs->a0 = regs->orig_a0; |
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regs_syscallid(regs) = __NR_restart_syscall; |
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regs->pc -= TRAP0_SIZE; |
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break; |
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} |
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} |
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/* |
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* If there is no signal to deliver, we just put the saved |
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* sigmask back. |
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*/ |
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restore_saved_sigmask(); |
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} |
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/* |
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* notification of userspace execution resumption |
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* - triggered by the _TIF_WORK_MASK flags |
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*/ |
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asmlinkage void do_notify_resume(struct pt_regs *regs, |
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unsigned long thread_info_flags) |
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{ |
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if (thread_info_flags & _TIF_UPROBE) |
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uprobe_notify_resume(regs); |
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/* Handle pending signal delivery */ |
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if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) |
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do_signal(regs); |
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if (thread_info_flags & _TIF_NOTIFY_RESUME) { |
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tracehook_notify_resume(regs); |
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rseq_handle_notify_resume(NULL, regs); |
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} |
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}
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