diff options
Diffstat (limited to 'arch/c6x/kernel/signal.c')
| -rw-r--r-- | arch/c6x/kernel/signal.c | 377 |
1 files changed, 377 insertions, 0 deletions
diff --git a/arch/c6x/kernel/signal.c b/arch/c6x/kernel/signal.c new file mode 100644 index 00000000000..304f675826e --- /dev/null +++ b/arch/c6x/kernel/signal.c @@ -0,0 +1,377 @@ +/* + * Port on Texas Instruments TMS320C6x architecture + * + * Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated + * Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com) + * + * Updated for 2.6.34: Mark Salter <msalter@redhat.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/kernel.h> +#include <linux/uaccess.h> +#include <linux/syscalls.h> +#include <linux/tracehook.h> + +#include <asm/ucontext.h> +#include <asm/cacheflush.h> + + +#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) + +/* + * Do a signal return, undo the signal stack. + */ + +#define RETCODE_SIZE (9 << 2) /* 9 instructions = 36 bytes */ + +struct rt_sigframe { + struct siginfo __user *pinfo; + void __user *puc; + struct siginfo info; + struct ucontext uc; + unsigned long retcode[RETCODE_SIZE >> 2]; +}; + +static int restore_sigcontext(struct pt_regs *regs, + struct sigcontext __user *sc) +{ + int err = 0; + + /* The access_ok check was done by caller, so use __get_user here */ +#define COPY(x) (err |= __get_user(regs->x, &sc->sc_##x)) + + COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8); + COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9); + COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9); + + COPY(a16); COPY(a17); COPY(a18); COPY(a19); + COPY(a20); COPY(a21); COPY(a22); COPY(a23); + COPY(a24); COPY(a25); COPY(a26); COPY(a27); + COPY(a28); COPY(a29); COPY(a30); COPY(a31); + COPY(b16); COPY(b17); COPY(b18); COPY(b19); + COPY(b20); COPY(b21); COPY(b22); COPY(b23); + COPY(b24); COPY(b25); COPY(b26); COPY(b27); + COPY(b28); COPY(b29); COPY(b30); COPY(b31); + + COPY(csr); COPY(pc); + +#undef COPY + + return err; +} + +asmlinkage int do_rt_sigreturn(struct pt_regs *regs) +{ + struct rt_sigframe __user *frame; + sigset_t set; + + /* + * Since we stacked the signal on a dword boundary, + * 'sp' should be dword aligned here. If it's + * not, then the user is trying to mess with us. + */ + if (regs->sp & 7) + goto badframe; + + frame = (struct rt_sigframe __user *) ((unsigned long) regs->sp + 8); + + if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) + goto badframe; + if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) + goto badframe; + + sigdelsetmask(&set, ~_BLOCKABLE); + spin_lock_irq(¤t->sighand->siglock); + current->blocked = set; + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) + goto badframe; + + return regs->a4; + +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, + unsigned long mask) +{ + int err = 0; + + err |= __put_user(mask, &sc->sc_mask); + + /* The access_ok check was done by caller, so use __put_user here */ +#define COPY(x) (err |= __put_user(regs->x, &sc->sc_##x)) + + COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8); + COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9); + COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9); + + COPY(a16); COPY(a17); COPY(a18); COPY(a19); + COPY(a20); COPY(a21); COPY(a22); COPY(a23); + COPY(a24); COPY(a25); COPY(a26); COPY(a27); + COPY(a28); COPY(a29); COPY(a30); COPY(a31); + COPY(b16); COPY(b17); COPY(b18); COPY(b19); + COPY(b20); COPY(b21); COPY(b22); COPY(b23); + COPY(b24); COPY(b25); COPY(b26); COPY(b27); + COPY(b28); COPY(b29); COPY(b30); COPY(b31); + + COPY(csr); COPY(pc); + +#undef COPY + + return err; +} + +static inline void __user *get_sigframe(struct k_sigaction *ka, + struct pt_regs *regs, + unsigned long framesize) +{ + unsigned long sp = regs->sp; + + /* + * This is the X/Open sanctioned signal stack switching. + */ + if ((ka->sa.sa_flags & SA_ONSTACK) && sas_ss_flags(sp) == 0) + sp = current->sas_ss_sp + current->sas_ss_size; + + /* + * No matter what happens, 'sp' must be dword + * aligned. Otherwise, nasty things will happen + */ + return (void __user *)((sp - framesize) & ~7); +} + +static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info, + sigset_t *set, struct pt_regs *regs) +{ + struct rt_sigframe __user *frame; + unsigned long __user *retcode; + int err = 0; + + frame = get_sigframe(ka, regs, sizeof(*frame)); + + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) + goto segv_and_exit; + + err |= __put_user(&frame->info, &frame->pinfo); + err |= __put_user(&frame->uc, &frame->puc); + err |= copy_siginfo_to_user(&frame->info, info); + + /* Clear all the bits of the ucontext we don't use. */ + err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext)); + + err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]); + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); + + /* Set up to return from userspace */ + retcode = (unsigned long __user *) &frame->retcode; + + /* The access_ok check was done above, so use __put_user here */ +#define COPY(x) (err |= __put_user(x, retcode++)) + + COPY(0x0000002AUL | (__NR_rt_sigreturn << 7)); + /* MVK __NR_rt_sigreturn,B0 */ + COPY(0x10000000UL); /* SWE */ + COPY(0x00006000UL); /* NOP 4 */ + COPY(0x00006000UL); /* NOP 4 */ + COPY(0x00006000UL); /* NOP 4 */ + COPY(0x00006000UL); /* NOP 4 */ + COPY(0x00006000UL); /* NOP 4 */ + COPY(0x00006000UL); /* NOP 4 */ + COPY(0x00006000UL); /* NOP 4 */ + +#undef COPY + + if (err) + goto segv_and_exit; + + flush_icache_range((unsigned long) &frame->retcode, + (unsigned long) &frame->retcode + RETCODE_SIZE); + + retcode = (unsigned long __user *) &frame->retcode; + + /* Change user context to branch to signal handler */ + regs->sp = (unsigned long) frame - 8; + regs->b3 = (unsigned long) retcode; + regs->pc = (unsigned long) ka->sa.sa_handler; + + /* Give the signal number to the handler */ + regs->a4 = signr; + + /* + * For realtime signals we must also set the second and third + * arguments for the signal handler. + * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06 + */ + regs->b4 = (unsigned long)&frame->info; + regs->a6 = (unsigned long)&frame->uc; + + return 0; + +segv_and_exit: + force_sigsegv(signr, current); + return -EFAULT; +} + +static inline void +handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler) +{ + switch (regs->a4) { + case -ERESTARTNOHAND: + if (!has_handler) + goto do_restart; + regs->a4 = -EINTR; + break; + + case -ERESTARTSYS: + if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) { + regs->a4 = -EINTR; + break; + } + /* fallthrough */ + case -ERESTARTNOINTR: +do_restart: + regs->a4 = regs->orig_a4; + regs->pc -= 4; + break; + } +} + +/* + * handle the actual delivery of a signal to userspace + */ +static int handle_signal(int sig, + siginfo_t *info, struct k_sigaction *ka, + sigset_t *oldset, struct pt_regs *regs, + int syscall) +{ + int ret; + + /* Are we from a system call? */ + if (syscall) { + /* If so, check system call restarting.. */ + switch (regs->a4) { + case -ERESTART_RESTARTBLOCK: + case -ERESTARTNOHAND: + regs->a4 = -EINTR; + break; + + case -ERESTARTSYS: + if (!(ka->sa.sa_flags & SA_RESTART)) { + regs->a4 = -EINTR; + break; + } + + /* fallthrough */ + case -ERESTARTNOINTR: + regs->a4 = regs->orig_a4; + regs->pc -= 4; + } + } + + /* Set up the stack frame */ + ret = setup_rt_frame(sig, ka, info, oldset, regs); + if (ret == 0) { + spin_lock_irq(¤t->sighand->siglock); + sigorsets(¤t->blocked, ¤t->blocked, + &ka->sa.sa_mask); + if (!(ka->sa.sa_flags & SA_NODEFER)) + sigaddset(¤t->blocked, sig); + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + } + + return ret; +} + +/* + * handle a potential signal + */ +static void do_signal(struct pt_regs *regs, int syscall) +{ + struct k_sigaction ka; + siginfo_t info; + sigset_t *oldset; + int signr; + + /* we want the common case to go fast, which is why we may in certain + * cases get here from kernel mode */ + if (!user_mode(regs)) + return; + + if (test_thread_flag(TIF_RESTORE_SIGMASK)) + oldset = ¤t->saved_sigmask; + else + oldset = ¤t->blocked; + + signr = get_signal_to_deliver(&info, &ka, regs, NULL); + if (signr > 0) { + if (handle_signal(signr, &info, &ka, oldset, + regs, syscall) == 0) { + /* a signal was successfully delivered; the saved + * sigmask will have been stored in the signal frame, + * and will be restored by sigreturn, so we can simply + * clear the TIF_RESTORE_SIGMASK flag */ + if (test_thread_flag(TIF_RESTORE_SIGMASK)) + clear_thread_flag(TIF_RESTORE_SIGMASK); + + tracehook_signal_handler(signr, &info, &ka, regs, 0); + } + + return; + } + + /* did we come from a system call? */ + if (syscall) { + /* restart the system call - no handlers present */ + switch (regs->a4) { + case -ERESTARTNOHAND: + case -ERESTARTSYS: + case -ERESTARTNOINTR: + regs->a4 = regs->orig_a4; + regs->pc -= 4; + break; + + case -ERESTART_RESTARTBLOCK: + regs->a4 = regs->orig_a4; + regs->b0 = __NR_restart_syscall; + regs->pc -= 4; + break; + } + } + + /* if there's no signal to deliver, we just put the saved sigmask + * back */ + if (test_thread_flag(TIF_RESTORE_SIGMASK)) { + clear_thread_flag(TIF_RESTORE_SIGMASK); + sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); + } +} + +/* + * notification of userspace execution resumption + * - triggered by current->work.notify_resume + */ +asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags, + int syscall) +{ + /* deal with pending signal delivery */ + if (thread_info_flags & ((1 << TIF_SIGPENDING) | + (1 << TIF_RESTORE_SIGMASK))) + do_signal(regs, syscall); + + if (thread_info_flags & (1 << TIF_NOTIFY_RESUME)) { + clear_thread_flag(TIF_NOTIFY_RESUME); + tracehook_notify_resume(regs); + if (current->replacement_session_keyring) + key_replace_session_keyring(); + } +} |