diff options
Diffstat (limited to 'arch/hexagon/kernel/signal.c')
| -rw-r--r-- | arch/hexagon/kernel/signal.c | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/arch/hexagon/kernel/signal.c b/arch/hexagon/kernel/signal.c new file mode 100644 index 000000000..bcba31e9e --- /dev/null +++ b/arch/hexagon/kernel/signal.c @@ -0,0 +1,256 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Signal support for Hexagon processor + * + * Copyright (c) 2010-2012, The Linux Foundation. All rights reserved. + */ + +#include <linux/linkage.h> +#include <linux/syscalls.h> +#include <linux/sched/task_stack.h> + +#include <asm/registers.h> +#include <asm/thread_info.h> +#include <asm/unistd.h> +#include <linux/uaccess.h> +#include <asm/ucontext.h> +#include <asm/cacheflush.h> +#include <asm/signal.h> +#include <asm/vdso.h> + +struct rt_sigframe { + unsigned long tramp[2]; + struct siginfo info; + struct ucontext uc; +}; + +static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, + size_t frame_size) +{ + unsigned long sp = sigsp(regs->r29, ksig); + + return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1)); +} + +static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) +{ + unsigned long tmp; + int err = 0; + + err |= copy_to_user(&sc->sc_regs.r0, ®s->r00, + 32*sizeof(unsigned long)); + + err |= __put_user(regs->sa0, &sc->sc_regs.sa0); + err |= __put_user(regs->lc0, &sc->sc_regs.lc0); + err |= __put_user(regs->sa1, &sc->sc_regs.sa1); + err |= __put_user(regs->lc1, &sc->sc_regs.lc1); + err |= __put_user(regs->m0, &sc->sc_regs.m0); + err |= __put_user(regs->m1, &sc->sc_regs.m1); + err |= __put_user(regs->usr, &sc->sc_regs.usr); + err |= __put_user(regs->preds, &sc->sc_regs.p3_0); + err |= __put_user(regs->gp, &sc->sc_regs.gp); + err |= __put_user(regs->ugp, &sc->sc_regs.ugp); +#if CONFIG_HEXAGON_ARCH_VERSION >= 4 + err |= __put_user(regs->cs0, &sc->sc_regs.cs0); + err |= __put_user(regs->cs1, &sc->sc_regs.cs1); +#endif + tmp = pt_elr(regs); err |= __put_user(tmp, &sc->sc_regs.pc); + tmp = pt_cause(regs); err |= __put_user(tmp, &sc->sc_regs.cause); + tmp = pt_badva(regs); err |= __put_user(tmp, &sc->sc_regs.badva); + + return err; +} + +static int restore_sigcontext(struct pt_regs *regs, + struct sigcontext __user *sc) +{ + unsigned long tmp; + int err = 0; + + err |= copy_from_user(®s->r00, &sc->sc_regs.r0, + 32 * sizeof(unsigned long)); + + err |= __get_user(regs->sa0, &sc->sc_regs.sa0); + err |= __get_user(regs->lc0, &sc->sc_regs.lc0); + err |= __get_user(regs->sa1, &sc->sc_regs.sa1); + err |= __get_user(regs->lc1, &sc->sc_regs.lc1); + err |= __get_user(regs->m0, &sc->sc_regs.m0); + err |= __get_user(regs->m1, &sc->sc_regs.m1); + err |= __get_user(regs->usr, &sc->sc_regs.usr); + err |= __get_user(regs->preds, &sc->sc_regs.p3_0); + err |= __get_user(regs->gp, &sc->sc_regs.gp); + err |= __get_user(regs->ugp, &sc->sc_regs.ugp); +#if CONFIG_HEXAGON_ARCH_VERSION >= 4 + err |= __get_user(regs->cs0, &sc->sc_regs.cs0); + err |= __get_user(regs->cs1, &sc->sc_regs.cs1); +#endif + err |= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp); + + return err; +} + +/* + * Setup signal stack frame with siginfo structure + */ +static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, + struct pt_regs *regs) +{ + int err = 0; + struct rt_sigframe __user *frame; + struct hexagon_vdso *vdso = current->mm->context.vdso; + + frame = get_sigframe(ksig, regs, sizeof(struct rt_sigframe)); + + if (!access_ok(frame, sizeof(struct rt_sigframe))) + return -EFAULT; + + if (copy_siginfo_to_user(&frame->info, &ksig->info)) + return -EFAULT; + + /* The on-stack signal trampoline is no longer executed; + * however, the libgcc signal frame unwinding code checks for + * the presence of these two numeric magic values. + */ + err |= __put_user(0x7800d166, &frame->tramp[0]); + err |= __put_user(0x5400c004, &frame->tramp[1]); + err |= setup_sigcontext(regs, &frame->uc.uc_mcontext); + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); + err |= __save_altstack(&frame->uc.uc_stack, user_stack_pointer(regs)); + if (err) + return -EFAULT; + + /* Load r0/r1 pair with signumber/siginfo pointer... */ + regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32) + | (unsigned long long)ksig->sig; + regs->r02 = (unsigned long) &frame->uc; + regs->r31 = (unsigned long) vdso->rt_signal_trampoline; + pt_psp(regs) = (unsigned long) frame; + pt_set_elr(regs, (unsigned long)ksig->ka.sa.sa_handler); + + return 0; +} + +/* + * Setup invocation of signal handler + */ +static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) +{ + int ret; + + /* + * If we're handling a signal that aborted a system call, + * set up the error return value before adding the signal + * frame to the stack. + */ + + if (regs->syscall_nr >= 0) { + switch (regs->r00) { + case -ERESTART_RESTARTBLOCK: + case -ERESTARTNOHAND: + regs->r00 = -EINTR; + break; + case -ERESTARTSYS: + if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { + regs->r00 = -EINTR; + break; + } + fallthrough; + case -ERESTARTNOINTR: + regs->r06 = regs->syscall_nr; + pt_set_elr(regs, pt_elr(regs) - 4); + regs->r00 = regs->restart_r0; + break; + default: + break; + } + } + + /* + * Set up the stack frame; not doing the SA_SIGINFO thing. We + * only set up the rt_frame flavor. + */ + /* If there was an error on setup, no signal was delivered. */ + ret = setup_rt_frame(ksig, sigmask_to_save(), regs); + + signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); +} + +/* + * Called from return-from-event code. + */ +void do_signal(struct pt_regs *regs) +{ + struct ksignal ksig; + + if (!user_mode(regs)) + return; + + if (get_signal(&ksig)) { + handle_signal(&ksig, regs); + return; + } + + /* + * No (more) signals; if we came from a system call, handle the restart. + */ + + if (regs->syscall_nr >= 0) { + switch (regs->r00) { + case -ERESTARTNOHAND: + case -ERESTARTSYS: + case -ERESTARTNOINTR: + regs->r06 = regs->syscall_nr; + break; + case -ERESTART_RESTARTBLOCK: + regs->r06 = __NR_restart_syscall; + break; + default: + goto no_restart; + } + pt_set_elr(regs, pt_elr(regs) - 4); + regs->r00 = regs->restart_r0; + } + +no_restart: + /* If there's no signal to deliver, put the saved sigmask back */ + restore_saved_sigmask(); +} + +/* + * Architecture-specific wrappers for signal-related system calls + */ + +asmlinkage int sys_rt_sigreturn(void) +{ + struct pt_regs *regs = current_pt_regs(); + struct rt_sigframe __user *frame; + sigset_t blocked; + + /* Always make any pending restarted system calls return -EINTR */ + current->restart_block.fn = do_no_restart_syscall; + + frame = (struct rt_sigframe __user *)pt_psp(regs); + if (!access_ok(frame, sizeof(*frame))) + goto badframe; + if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked))) + goto badframe; + + set_current_blocked(&blocked); + + if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) + goto badframe; + + /* Restore the user's stack as well */ + pt_psp(regs) = regs->r29; + + regs->syscall_nr = -1; + + if (restore_altstack(&frame->uc.uc_stack)) + goto badframe; + + return regs->r00; + +badframe: + force_sig(SIGSEGV); + return 0; +} |