diff options
author | Paul Mundt <lethal@linux-sh.org> | 2007-11-10 20:07:57 +0900 |
---|---|---|
committer | Paul Mundt <lethal@linux-sh.org> | 2008-01-28 13:18:43 +0900 |
commit | f7a7b15344e2bccdd1c73d42685edfe7d43ec5b7 (patch) | |
tree | 87280639daf814c9a818994926785faf9daded88 /arch/sh/kernel/signal_64.c | |
parent | 76168c21b78a0bd684d4687d14a2bd76bcf92762 (diff) |
sh: Move in the SH-5 signal trampoline impl.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/kernel/signal_64.c')
-rw-r--r-- | arch/sh/kernel/signal_64.c | 754 |
1 files changed, 754 insertions, 0 deletions
diff --git a/arch/sh/kernel/signal_64.c b/arch/sh/kernel/signal_64.c new file mode 100644 index 00000000000..96ba81f324b --- /dev/null +++ b/arch/sh/kernel/signal_64.c @@ -0,0 +1,754 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * arch/sh64/kernel/signal.c + * + * Copyright (C) 2000, 2001 Paolo Alberelli + * Copyright (C) 2003 Paul Mundt + * Copyright (C) 2004 Richard Curnow + * + * Started from sh version. + * + */ +#include <linux/rwsem.h> +#include <linux/sched.h> +#include <linux/mm.h> +#include <linux/smp.h> +#include <linux/kernel.h> +#include <linux/signal.h> +#include <linux/errno.h> +#include <linux/wait.h> +#include <linux/personality.h> +#include <linux/freezer.h> +#include <linux/ptrace.h> +#include <linux/unistd.h> +#include <linux/stddef.h> +#include <asm/ucontext.h> +#include <asm/uaccess.h> +#include <asm/pgtable.h> +#include <asm/cacheflush.h> + +#define REG_RET 9 +#define REG_ARG1 2 +#define REG_ARG2 3 +#define REG_ARG3 4 +#define REG_SP 15 +#define REG_PR 18 +#define REF_REG_RET regs->regs[REG_RET] +#define REF_REG_SP regs->regs[REG_SP] +#define DEREF_REG_PR regs->regs[REG_PR] + +#define DEBUG_SIG 0 + +#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) + +asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset); + +/* + * Atomically swap in the new signal mask, and wait for a signal. + */ + +asmlinkage int +sys_sigsuspend(old_sigset_t mask, + unsigned long r3, unsigned long r4, unsigned long r5, + unsigned long r6, unsigned long r7, + struct pt_regs * regs) +{ + sigset_t saveset; + + mask &= _BLOCKABLE; + spin_lock_irq(¤t->sighand->siglock); + saveset = current->blocked; + siginitset(¤t->blocked, mask); + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + REF_REG_RET = -EINTR; + while (1) { + current->state = TASK_INTERRUPTIBLE; + schedule(); + regs->pc += 4; /* because sys_sigreturn decrements the pc */ + if (do_signal(regs, &saveset)) { + /* pc now points at signal handler. Need to decrement + it because entry.S will increment it. */ + regs->pc -= 4; + return -EINTR; + } + } +} + +asmlinkage int +sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, + unsigned long r4, unsigned long r5, unsigned long r6, + unsigned long r7, + struct pt_regs * regs) +{ + sigset_t saveset, newset; + + /* XXX: Don't preclude handling different sized sigset_t's. */ + if (sigsetsize != sizeof(sigset_t)) + return -EINVAL; + + if (copy_from_user(&newset, unewset, sizeof(newset))) + return -EFAULT; + sigdelsetmask(&newset, ~_BLOCKABLE); + spin_lock_irq(¤t->sighand->siglock); + saveset = current->blocked; + current->blocked = newset; + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + REF_REG_RET = -EINTR; + while (1) { + current->state = TASK_INTERRUPTIBLE; + schedule(); + regs->pc += 4; /* because sys_sigreturn decrements the pc */ + if (do_signal(regs, &saveset)) { + /* pc now points at signal handler. Need to decrement + it because entry.S will increment it. */ + regs->pc -= 4; + return -EINTR; + } + } +} + +asmlinkage int +sys_sigaction(int sig, const struct old_sigaction __user *act, + struct old_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_restorer, &act->sa_restorer)) + return -EFAULT; + __get_user(new_ka.sa.sa_flags, &act->sa_flags); + __get_user(mask, &act->sa_mask); + siginitset(&new_ka.sa.sa_mask, mask); + } + + 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_restorer, &oact->sa_restorer)) + return -EFAULT; + __put_user(old_ka.sa.sa_flags, &oact->sa_flags); + __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); + } + + return ret; +} + +asmlinkage int +sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, + unsigned long r4, unsigned long r5, unsigned long r6, + unsigned long r7, + struct pt_regs * regs) +{ + return do_sigaltstack(uss, uoss, REF_REG_SP); +} + + +/* + * Do a signal return; undo the signal stack. + */ + +struct sigframe +{ + struct sigcontext sc; + unsigned long extramask[_NSIG_WORDS-1]; + long long retcode[2]; +}; + +struct rt_sigframe +{ + struct siginfo __user *pinfo; + void *puc; + struct siginfo info; + struct ucontext uc; + long long retcode[2]; +}; + +#ifdef CONFIG_SH_FPU +static inline int +restore_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc) +{ + int err = 0; + int fpvalid; + + err |= __get_user (fpvalid, &sc->sc_fpvalid); + conditional_used_math(fpvalid); + if (! fpvalid) + return err; + + if (current == last_task_used_math) { + last_task_used_math = NULL; + regs->sr |= SR_FD; + } + + err |= __copy_from_user(¤t->thread.fpu.hard, &sc->sc_fpregs[0], + (sizeof(long long) * 32) + (sizeof(int) * 1)); + + return err; +} + +static inline int +setup_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc) +{ + int err = 0; + int fpvalid; + + fpvalid = !!used_math(); + err |= __put_user(fpvalid, &sc->sc_fpvalid); + if (! fpvalid) + return err; + + if (current == last_task_used_math) { + grab_fpu(); + fpsave(¤t->thread.fpu.hard); + release_fpu(); + last_task_used_math = NULL; + regs->sr |= SR_FD; + } + + err |= __copy_to_user(&sc->sc_fpregs[0], ¤t->thread.fpu.hard, + (sizeof(long long) * 32) + (sizeof(int) * 1)); + clear_used_math(); + + return err; +} +#else +static inline int +restore_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc) +{ + return 0; +} +static inline int +setup_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc) +{ + return 0; +} +#endif + +static int +restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, long long *r2_p) +{ + unsigned int err = 0; + unsigned long long current_sr, new_sr; +#define SR_MASK 0xffff8cfd + +#define COPY(x) err |= __get_user(regs->x, &sc->sc_##x) + + COPY(regs[0]); COPY(regs[1]); COPY(regs[2]); COPY(regs[3]); + COPY(regs[4]); COPY(regs[5]); COPY(regs[6]); COPY(regs[7]); + COPY(regs[8]); COPY(regs[9]); COPY(regs[10]); COPY(regs[11]); + COPY(regs[12]); COPY(regs[13]); COPY(regs[14]); COPY(regs[15]); + COPY(regs[16]); COPY(regs[17]); COPY(regs[18]); COPY(regs[19]); + COPY(regs[20]); COPY(regs[21]); COPY(regs[22]); COPY(regs[23]); + COPY(regs[24]); COPY(regs[25]); COPY(regs[26]); COPY(regs[27]); + COPY(regs[28]); COPY(regs[29]); COPY(regs[30]); COPY(regs[31]); + COPY(regs[32]); COPY(regs[33]); COPY(regs[34]); COPY(regs[35]); + COPY(regs[36]); COPY(regs[37]); COPY(regs[38]); COPY(regs[39]); + COPY(regs[40]); COPY(regs[41]); COPY(regs[42]); COPY(regs[43]); + COPY(regs[44]); COPY(regs[45]); COPY(regs[46]); COPY(regs[47]); + COPY(regs[48]); COPY(regs[49]); COPY(regs[50]); COPY(regs[51]); + COPY(regs[52]); COPY(regs[53]); COPY(regs[54]); COPY(regs[55]); + COPY(regs[56]); COPY(regs[57]); COPY(regs[58]); COPY(regs[59]); + COPY(regs[60]); COPY(regs[61]); COPY(regs[62]); + COPY(tregs[0]); COPY(tregs[1]); COPY(tregs[2]); COPY(tregs[3]); + COPY(tregs[4]); COPY(tregs[5]); COPY(tregs[6]); COPY(tregs[7]); + + /* Prevent the signal handler manipulating SR in a way that can + crash the kernel. i.e. only allow S, Q, M, PR, SZ, FR to be + modified */ + current_sr = regs->sr; + err |= __get_user(new_sr, &sc->sc_sr); + regs->sr &= SR_MASK; + regs->sr |= (new_sr & ~SR_MASK); + + COPY(pc); + +#undef COPY + + /* Must do this last in case it sets regs->sr.fd (i.e. after rest of sr + * has been restored above.) */ + err |= restore_sigcontext_fpu(regs, sc); + + regs->syscall_nr = -1; /* disable syscall checks */ + err |= __get_user(*r2_p, &sc->sc_regs[REG_RET]); + return err; +} + +asmlinkage int sys_sigreturn(unsigned long r2, unsigned long r3, + unsigned long r4, unsigned long r5, + unsigned long r6, unsigned long r7, + struct pt_regs * regs) +{ + struct sigframe __user *frame = (struct sigframe __user *) (long) REF_REG_SP; + sigset_t set; + long long ret; + + if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) + goto badframe; + + if (__get_user(set.sig[0], &frame->sc.oldmask) + || (_NSIG_WORDS > 1 + && __copy_from_user(&set.sig[1], &frame->extramask, + sizeof(frame->extramask)))) + 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->sc, &ret)) + goto badframe; + regs->pc -= 4; + + return (int) ret; + +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +asmlinkage int sys_rt_sigreturn(unsigned long r2, unsigned long r3, + unsigned long r4, unsigned long r5, + unsigned long r6, unsigned long r7, + struct pt_regs * regs) +{ + struct rt_sigframe __user *frame = (struct rt_sigframe __user *) (long) REF_REG_SP; + sigset_t set; + stack_t __user st; + long long ret; + + 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, &ret)) + goto badframe; + regs->pc -= 4; + + if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st))) + goto badframe; + /* It is more difficult to avoid calling this function than to + call it and ignore errors. */ + do_sigaltstack(&st, NULL, REF_REG_SP); + + return (int) ret; + +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +/* + * Set up a signal frame. + */ + +static int +setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, + unsigned long mask) +{ + int err = 0; + + /* Do this first, otherwise is this sets sr->fd, that value isn't preserved. */ + err |= setup_sigcontext_fpu(regs, sc); + +#define COPY(x) err |= __put_user(regs->x, &sc->sc_##x) + + COPY(regs[0]); COPY(regs[1]); COPY(regs[2]); COPY(regs[3]); + COPY(regs[4]); COPY(regs[5]); COPY(regs[6]); COPY(regs[7]); + COPY(regs[8]); COPY(regs[9]); COPY(regs[10]); COPY(regs[11]); + COPY(regs[12]); COPY(regs[13]); COPY(regs[14]); COPY(regs[15]); + COPY(regs[16]); COPY(regs[17]); COPY(regs[18]); COPY(regs[19]); + COPY(regs[20]); COPY(regs[21]); COPY(regs[22]); COPY(regs[23]); + COPY(regs[24]); COPY(regs[25]); COPY(regs[26]); COPY(regs[27]); + COPY(regs[28]); COPY(regs[29]); COPY(regs[30]); COPY(regs[31]); + COPY(regs[32]); COPY(regs[33]); COPY(regs[34]); COPY(regs[35]); + COPY(regs[36]); COPY(regs[37]); COPY(regs[38]); COPY(regs[39]); + COPY(regs[40]); COPY(regs[41]); COPY(regs[42]); COPY(regs[43]); + COPY(regs[44]); COPY(regs[45]); COPY(regs[46]); COPY(regs[47]); + COPY(regs[48]); COPY(regs[49]); COPY(regs[50]); COPY(regs[51]); + COPY(regs[52]); COPY(regs[53]); COPY(regs[54]); COPY(regs[55]); + COPY(regs[56]); COPY(regs[57]); COPY(regs[58]); COPY(regs[59]); + COPY(regs[60]); COPY(regs[61]); COPY(regs[62]); + COPY(tregs[0]); COPY(tregs[1]); COPY(tregs[2]); COPY(tregs[3]); + COPY(tregs[4]); COPY(tregs[5]); COPY(tregs[6]); COPY(tregs[7]); + COPY(sr); COPY(pc); + +#undef COPY + + err |= __put_user(mask, &sc->oldmask); + + return err; +} + +/* + * Determine which stack to use.. + */ +static inline void __user * +get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size) +{ + if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp)) + sp = current->sas_ss_sp + current->sas_ss_size; + + return (void __user *)((sp - frame_size) & -8ul); +} + +void sa_default_restorer(void); /* See comments below */ +void sa_default_rt_restorer(void); /* See comments below */ + +static void setup_frame(int sig, struct k_sigaction *ka, + sigset_t *set, struct pt_regs *regs) +{ + struct sigframe __user *frame; + int err = 0; + int signal; + + frame = get_sigframe(ka, regs->regs[REG_SP], sizeof(*frame)); + + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) + goto give_sigsegv; + + signal = current_thread_info()->exec_domain + && current_thread_info()->exec_domain->signal_invmap + && sig < 32 + ? current_thread_info()->exec_domain->signal_invmap[sig] + : sig; + + err |= setup_sigcontext(&frame->sc, regs, set->sig[0]); + + /* Give up earlier as i386, in case */ + if (err) + goto give_sigsegv; + + if (_NSIG_WORDS > 1) { + err |= __copy_to_user(frame->extramask, &set->sig[1], + sizeof(frame->extramask)); } + + /* Give up earlier as i386, in case */ + if (err) + goto give_sigsegv; + + /* Set up to return from userspace. If provided, use a stub + already in userspace. */ + if (ka->sa.sa_flags & SA_RESTORER) { + DEREF_REG_PR = (unsigned long) ka->sa.sa_restorer | 0x1; + + /* + * On SH5 all edited pointers are subject to NEFF + */ + DEREF_REG_PR = (DEREF_REG_PR & NEFF_SIGN) ? + (DEREF_REG_PR | NEFF_MASK) : DEREF_REG_PR; + } else { + /* + * Different approach on SH5. + * . Endianness independent asm code gets placed in entry.S . + * This is limited to four ASM instructions corresponding + * to two long longs in size. + * . err checking is done on the else branch only + * . flush_icache_range() is called upon __put_user() only + * . all edited pointers are subject to NEFF + * . being code, linker turns ShMedia bit on, always + * dereference index -1. + */ + DEREF_REG_PR = (unsigned long) frame->retcode | 0x01; + DEREF_REG_PR = (DEREF_REG_PR & NEFF_SIGN) ? + (DEREF_REG_PR | NEFF_MASK) : DEREF_REG_PR; + + if (__copy_to_user(frame->retcode, + (unsigned long long)sa_default_restorer & (~1), 16) != 0) + goto give_sigsegv; + + /* Cohere the trampoline with the I-cache. */ + flush_cache_sigtramp(DEREF_REG_PR-1, DEREF_REG_PR-1+16); + } + + /* + * Set up registers for signal handler. + * All edited pointers are subject to NEFF. + */ + regs->regs[REG_SP] = (unsigned long) frame; + regs->regs[REG_SP] = (regs->regs[REG_SP] & NEFF_SIGN) ? + (regs->regs[REG_SP] | NEFF_MASK) : regs->regs[REG_SP]; + regs->regs[REG_ARG1] = signal; /* Arg for signal handler */ + + /* FIXME: + The glibc profiling support for SH-5 needs to be passed a sigcontext + so it can retrieve the PC. At some point during 2003 the glibc + support was changed to receive the sigcontext through the 2nd + argument, but there are still versions of libc.so in use that use + the 3rd argument. Until libc.so is stabilised, pass the sigcontext + through both 2nd and 3rd arguments. + */ + + regs->regs[REG_ARG2] = (unsigned long long)(unsigned long)(signed long)&frame->sc; + regs->regs[REG_ARG3] = (unsigned long long)(unsigned long)(signed long)&frame->sc; + + regs->pc = (unsigned long) ka->sa.sa_handler; + regs->pc = (regs->pc & NEFF_SIGN) ? (regs->pc | NEFF_MASK) : regs->pc; + + set_fs(USER_DS); + +#if DEBUG_SIG + /* Broken %016Lx */ + printk("SIG deliver (#%d,%s:%d): sp=%p pc=%08Lx%08Lx link=%08Lx%08Lx\n", + signal, + current->comm, current->pid, frame, + regs->pc >> 32, regs->pc & 0xffffffff, + DEREF_REG_PR >> 32, DEREF_REG_PR & 0xffffffff); +#endif + + return; + +give_sigsegv: + force_sigsegv(sig, current); +} + +static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, + sigset_t *set, struct pt_regs *regs) +{ + struct rt_sigframe __user *frame; + int err = 0; + int signal; + + frame = get_sigframe(ka, regs->regs[REG_SP], sizeof(*frame)); + + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) + goto give_sigsegv; + + signal = current_thread_info()->exec_domain + && current_thread_info()->exec_domain->signal_invmap + && sig < 32 + ? current_thread_info()->exec_domain->signal_invmap[sig] + : sig; + + err |= __put_user(&frame->info, &frame->pinfo); + err |= __put_user(&frame->uc, &frame->puc); + err |= copy_siginfo_to_user(&frame->info, info); + + /* Give up earlier as i386, in case */ + if (err) + goto give_sigsegv; + + /* Create the ucontext. */ + err |= __put_user(0, &frame->uc.uc_flags); + err |= __put_user(0, &frame->uc.uc_link); + err |= __put_user((void *)current->sas_ss_sp, + &frame->uc.uc_stack.ss_sp); + err |= __put_user(sas_ss_flags(regs->regs[REG_SP]), + &frame->uc.uc_stack.ss_flags); + err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); + err |= setup_sigcontext(&frame->uc.uc_mcontext, + regs, set->sig[0]); + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); + + /* Give up earlier as i386, in case */ + if (err) + goto give_sigsegv; + + /* Set up to return from userspace. If provided, use a stub + already in userspace. */ + if (ka->sa.sa_flags & SA_RESTORER) { + DEREF_REG_PR = (unsigned long) ka->sa.sa_restorer | 0x1; + + /* + * On SH5 all edited pointers are subject to NEFF + */ + DEREF_REG_PR = (DEREF_REG_PR & NEFF_SIGN) ? + (DEREF_REG_PR | NEFF_MASK) : DEREF_REG_PR; + } else { + /* + * Different approach on SH5. + * . Endianness independent asm code gets placed in entry.S . + * This is limited to four ASM instructions corresponding + * to two long longs in size. + * . err checking is done on the else branch only + * . flush_icache_range() is called upon __put_user() only + * . all edited pointers are subject to NEFF + * . being code, linker turns ShMedia bit on, always + * dereference index -1. + */ + + DEREF_REG_PR = (unsigned long) frame->retcode | 0x01; + DEREF_REG_PR = (DEREF_REG_PR & NEFF_SIGN) ? + (DEREF_REG_PR | NEFF_MASK) : DEREF_REG_PR; + + if (__copy_to_user(frame->retcode, + (unsigned long long)sa_default_rt_restorer & (~1), 16) != 0) + goto give_sigsegv; + + flush_icache_range(DEREF_REG_PR-1, DEREF_REG_PR-1+15); + } + + /* + * Set up registers for signal handler. + * All edited pointers are subject to NEFF. + */ + regs->regs[REG_SP] = (unsigned long) frame; + regs->regs[REG_SP] = (regs->regs[REG_SP] & NEFF_SIGN) ? + (regs->regs[REG_SP] | NEFF_MASK) : regs->regs[REG_SP]; + regs->regs[REG_ARG1] = signal; /* Arg for signal handler */ + regs->regs[REG_ARG2] = (unsigned long long)(unsigned long)(signed long)&frame->info; + regs->regs[REG_ARG3] = (unsigned long long)(unsigned long)(signed long)&frame->uc.uc_mcontext; + regs->pc = (unsigned long) ka->sa.sa_handler; + regs->pc = (regs->pc & NEFF_SIGN) ? (regs->pc | NEFF_MASK) : regs->pc; + + set_fs(USER_DS); + +#if DEBUG_SIG + /* Broken %016Lx */ + printk("SIG deliver (#%d,%s:%d): sp=%p pc=%08Lx%08Lx link=%08Lx%08Lx\n", + signal, + current->comm, current->pid, frame, + regs->pc >> 32, regs->pc & 0xffffffff, + DEREF_REG_PR >> 32, DEREF_REG_PR & 0xffffffff); +#endif + + return; + +give_sigsegv: + force_sigsegv(sig, current); +} + +/* + * OK, we're invoking a handler + */ + +static void +handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, + sigset_t *oldset, struct pt_regs * regs) +{ + /* Are we from a system call? */ + if (regs->syscall_nr >= 0) { + /* If so, check system call restarting.. */ + switch (regs->regs[REG_RET]) { + case -ERESTART_RESTARTBLOCK: + case -ERESTARTNOHAND: + regs->regs[REG_RET] = -EINTR; + break; + + case -ERESTARTSYS: + if (!(ka->sa.sa_flags & SA_RESTART)) { + regs->regs[REG_RET] = -EINTR; + break; + } + /* fallthrough */ + case -ERESTARTNOINTR: + /* Decode syscall # */ + regs->regs[REG_RET] = regs->syscall_nr; + regs->pc -= 4; + } + } + + /* Set up the stack frame */ + if (ka->sa.sa_flags & SA_SIGINFO) + setup_rt_frame(sig, ka, info, oldset, regs); + else + setup_frame(sig, ka, oldset, regs); + + 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); +} + +/* + * 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. + */ +int do_signal(struct pt_regs *regs, sigset_t *oldset) +{ + siginfo_t info; + int signr; + struct k_sigaction ka; + + /* + * We want the common case to go fast, which + * is why we may in certain cases get here from + * kernel mode. Just return without doing anything + * if so. + */ + if (!user_mode(regs)) + return 1; + + if (try_to_freeze()) + goto no_signal; + + if (test_thread_flag(TIF_RESTORE_SIGMASK)) + oldset = ¤t->saved_sigmask; + else if (!oldset) + oldset = ¤t->blocked; + + signr = get_signal_to_deliver(&info, &ka, regs, 0); + + if (signr > 0) { + /* Whee! Actually deliver the signal. */ + handle_signal(signr, &info, &ka, oldset, regs); + + /* + * If a signal was successfully delivered, the saved sigmask + * is in its frame, and we can clear the TIF_RESTORE_SIGMASK + * flag. + */ + if (test_thread_flag(TIF_RESTORE_SIGMASK)) + clear_thread_flag(TIF_RESTORE_SIGMASK); + + return 1; + } + +no_signal: + /* Did we come from a system call? */ + if (regs->syscall_nr >= 0) { + /* Restart the system call - no handlers present */ + switch (regs->regs[REG_RET]) { + case -ERESTARTNOHAND: + case -ERESTARTSYS: + case -ERESTARTNOINTR: + /* Decode Syscall # */ + regs->regs[REG_RET] = regs->syscall_nr; + regs->pc -= 4; + break; + + case -ERESTART_RESTARTBLOCK: + regs->regs[REG_RET] = __NR_restart_syscall; + regs->pc -= 4; + break; + } + } + + /* No signal to deliver -- 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); + } + + return 0; +} |