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/*
* linux/arch/arm/kernel/signal.c
*
* Copyright (C) 1995-2001 Russell King
*
* 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/config.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/personality.h>
#include <linux/tty.h>
#include <linux/elf.h>
#include <asm/pgalloc.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include "ptrace.h"
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
/*
* For ARM syscalls, we encode the syscall number into the instruction.
*/
#define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn))
#define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn))
/*
* For Thumb syscalls, we pass the syscall number via r7. We therefore
* need two 16-bit instructions.
*/
#define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
#define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
static const unsigned long retcodes[4] = {
SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN,
SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN
};
asmlinkage int do_signal(sigset_t *oldset, struct pt_regs * regs, int syscall);
int copy_siginfo_to_user(siginfo_t *to, siginfo_t *from)
{
int err = -EFAULT;;
if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
goto out;
if (from->si_code < 0)
return __copy_to_user(to, from, sizeof(siginfo_t));
/* If you change siginfo_t structure, please be sure
this code is fixed accordingly.
It should never copy any pad contained in the structure
to avoid security leaks, but must copy the generic
3 ints plus the relevant union member. */
err = __put_user(from->si_signo, &to->si_signo);
err |= __put_user(from->si_errno, &to->si_errno);
err |= __put_user((short)from->si_code, &to->si_code);
/* First 32bits of unions are always present. */
err |= __put_user(from->si_pid, &to->si_pid);
switch (from->si_code >> 16) {
case __SI_FAULT >> 16:
break;
case __SI_CHLD >> 16:
err |= __put_user(from->si_utime, &to->si_utime);
err |= __put_user(from->si_stime, &to->si_stime);
err |= __put_user(from->si_status, &to->si_status);
default:
err |= __put_user(from->si_uid, &to->si_uid);
break;
/* case __SI_RT: This is not generated by the kernel as of now. */
}
out:
return err;
}
/*
* atomically swap in the new signal mask, and wait for a signal.
*/
asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask, struct pt_regs *regs)
{
sigset_t saveset;
mask &= _BLOCKABLE;
spin_lock_irq(¤t->sigmask_lock);
saveset = current->blocked;
siginitset(¤t->blocked, mask);
recalc_sigpending(current);
spin_unlock_irq(¤t->sigmask_lock);
regs->ARM_r0 = -EINTR;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (do_signal(&saveset, regs, 0))
return regs->ARM_r0;
}
}
asmlinkage int
sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, 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->sigmask_lock);
saveset = current->blocked;
current->blocked = newset;
recalc_sigpending(current);
spin_unlock_irq(¤t->sigmask_lock);
regs->ARM_r0 = -EINTR;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (do_signal(&saveset, regs, 0))
return regs->ARM_r0;
}
}
asmlinkage int
sys_sigaction(int sig, const struct old_sigaction *act,
struct old_sigaction *oact)
{
struct k_sigaction new_ka, old_ka;
int ret;
if (act) {
old_sigset_t mask;
if (verify_area(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 (verify_area(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;
}
/*
* Do a signal return; undo the signal stack.
*/
struct sigframe
{
struct sigcontext sc;
unsigned long extramask[_NSIG_WORDS-1];
unsigned long retcode;
};
struct rt_sigframe
{
struct siginfo *pinfo;
void *puc;
struct siginfo info;
struct ucontext uc;
unsigned long retcode;
};
static int
restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc)
{
int err = 0;
__get_user_error(regs->ARM_r0, &sc->arm_r0, err);
__get_user_error(regs->ARM_r1, &sc->arm_r1, err);
__get_user_error(regs->ARM_r2, &sc->arm_r2, err);
__get_user_error(regs->ARM_r3, &sc->arm_r3, err);
__get_user_error(regs->ARM_r4, &sc->arm_r4, err);
__get_user_error(regs->ARM_r5, &sc->arm_r5, err);
__get_user_error(regs->ARM_r6, &sc->arm_r6, err);
__get_user_error(regs->ARM_r7, &sc->arm_r7, err);
__get_user_error(regs->ARM_r8, &sc->arm_r8, err);
__get_user_error(regs->ARM_r9, &sc->arm_r9, err);
__get_user_error(regs->ARM_r10, &sc->arm_r10, err);
__get_user_error(regs->ARM_fp, &sc->arm_fp, err);
__get_user_error(regs->ARM_ip, &sc->arm_ip, err);
__get_user_error(regs->ARM_sp, &sc->arm_sp, err);
__get_user_error(regs->ARM_lr, &sc->arm_lr, err);
__get_user_error(regs->ARM_pc, &sc->arm_pc, err);
#ifdef CONFIG_CPU_32
__get_user_error(regs->ARM_cpsr, &sc->arm_cpsr, err);
#endif
err |= !valid_user_regs(regs);
return err;
}
asmlinkage int sys_sigreturn(struct pt_regs *regs)
{
struct sigframe *frame;
sigset_t set;
/*
* Since we stacked the signal on a 64-bit boundary,
* then 'sp' should be word aligned here. If it's
* not, then the user is trying to mess with us.
*/
if (regs->ARM_sp & 7)
goto badframe;
frame = (struct sigframe *)regs->ARM_sp;
if (verify_area(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->sigmask_lock);
current->blocked = set;
recalc_sigpending(current);
spin_unlock_irq(¤t->sigmask_lock);
if (restore_sigcontext(regs, &frame->sc))
goto badframe;
/* Send SIGTRAP if we're single-stepping */
if (ptrace_cancel_bpt(current))
send_sig(SIGTRAP, current, 1);
return regs->ARM_r0;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
{
struct rt_sigframe *frame;
sigset_t set;
/*
* Since we stacked the signal on a 64-bit boundary,
* then 'sp' should be word aligned here. If it's
* not, then the user is trying to mess with us.
*/
if (regs->ARM_sp & 7)
goto badframe;
frame = (struct rt_sigframe *)regs->ARM_sp;
if (verify_area(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->sigmask_lock);
current->blocked = set;
recalc_sigpending(current);
spin_unlock_irq(¤t->sigmask_lock);
if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
goto badframe;
/* Send SIGTRAP if we're single-stepping */
if (ptrace_cancel_bpt(current))
send_sig(SIGTRAP, current, 1);
return regs->ARM_r0;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
static int
setup_sigcontext(struct sigcontext *sc, /*struct _fpstate *fpstate,*/
struct pt_regs *regs, unsigned long mask)
{
int err = 0;
__put_user_error(regs->ARM_r0, &sc->arm_r0, err);
__put_user_error(regs->ARM_r1, &sc->arm_r1, err);
__put_user_error(regs->ARM_r2, &sc->arm_r2, err);
__put_user_error(regs->ARM_r3, &sc->arm_r3, err);
__put_user_error(regs->ARM_r4, &sc->arm_r4, err);
__put_user_error(regs->ARM_r5, &sc->arm_r5, err);
__put_user_error(regs->ARM_r6, &sc->arm_r6, err);
__put_user_error(regs->ARM_r7, &sc->arm_r7, err);
__put_user_error(regs->ARM_r8, &sc->arm_r8, err);
__put_user_error(regs->ARM_r9, &sc->arm_r9, err);
__put_user_error(regs->ARM_r10, &sc->arm_r10, err);
__put_user_error(regs->ARM_fp, &sc->arm_fp, err);
__put_user_error(regs->ARM_ip, &sc->arm_ip, err);
__put_user_error(regs->ARM_sp, &sc->arm_sp, err);
__put_user_error(regs->ARM_lr, &sc->arm_lr, err);
__put_user_error(regs->ARM_pc, &sc->arm_pc, err);
#ifdef CONFIG_CPU_32
__put_user_error(regs->ARM_cpsr, &sc->arm_cpsr, err);
#endif
__put_user_error(current->thread.trap_no, &sc->trap_no, err);
__put_user_error(current->thread.error_code, &sc->error_code, err);
__put_user_error(current->thread.address, &sc->fault_address, err);
__put_user_error(mask, &sc->oldmask, err);
return err;
}
static inline void *
get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
{
unsigned long sp = regs->ARM_sp;
/*
* This is the X/Open sanctioned signal stack switching.
*/
if ((ka->sa.sa_flags & SA_ONSTACK) && sas_ss_flags(sp))
sp = current->sas_ss_sp + current->sas_ss_size;
/*
* ATPCS B01 mandates 8-byte alignment
*/
return (void *)((sp - framesize) & ~7);
}
static int
setup_return(struct pt_regs *regs, struct k_sigaction *ka,
unsigned long *rc, void *frame, int usig)
{
unsigned long handler = (unsigned long)ka->sa.sa_handler;
unsigned long retcode;
int thumb = 0;
#ifdef CONFIG_CPU_32
unsigned long cpsr = regs->ARM_cpsr;
/*
* Maybe we need to deliver a 32-bit signal to a 26-bit task.
*/
if (ka->sa.sa_flags & SA_THIRTYTWO)
cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
#ifdef CONFIG_ARM_THUMB
if (elf_hwcap & HWCAP_THUMB) {
/*
* The LSB of the handler determines if we're going to
* be using THUMB or ARM mode for this signal handler.
*/
thumb = handler & 1;
if (thumb)
cpsr |= T_BIT;
else
cpsr &= ~T_BIT;
}
#endif
#endif
if (ka->sa.sa_flags & SA_RESTORER) {
retcode = (unsigned long)ka->sa.sa_restorer;
} else {
unsigned int idx = thumb;
if (ka->sa.sa_flags & SA_SIGINFO)
idx += 2;
if (__put_user(retcodes[idx], rc))
return 1;
flush_icache_range((unsigned long)rc,
(unsigned long)(rc + 1));
retcode = ((unsigned long)rc) + thumb;
}
regs->ARM_r0 = usig;
regs->ARM_sp = (unsigned long)frame;
regs->ARM_lr = retcode;
regs->ARM_pc = handler & (thumb ? ~1 : ~3);
#ifdef CONFIG_CPU_32
regs->ARM_cpsr = cpsr;
#endif
return 0;
}
static int
setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
{
struct sigframe *frame = get_sigframe(ka, regs, sizeof(*frame));
int err = 0;
if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
return 1;
err |= setup_sigcontext(&frame->sc, /*&frame->fpstate,*/ regs, set->sig[0]);
if (_NSIG_WORDS > 1) {
err |= __copy_to_user(frame->extramask, &set->sig[1],
sizeof(frame->extramask));
}
if (err == 0)
err = setup_return(regs, ka, &frame->retcode, frame, usig);
return err;
}
static int
setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set, struct pt_regs *regs)
{
struct rt_sigframe *frame = get_sigframe(ka, regs, sizeof(*frame));
int err = 0;
if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
return 1;
__put_user_error(&frame->info, &frame->pinfo, err);
__put_user_error(&frame->uc, &frame->puc, err);
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, /*&frame->fpstate,*/
regs, set->sig[0]);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
if (err == 0)
err = setup_return(regs, ka, &frame->retcode, frame, usig);
if (err == 0) {
/*
* 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->ARM_r1 = (unsigned long)frame->pinfo;
regs->ARM_r2 = (unsigned long)frame->puc;
}
return err;
}
/*
* OK, we're invoking a handler
*/
static void
handle_signal(unsigned long sig, struct k_sigaction *ka,
siginfo_t *info, sigset_t *oldset, struct pt_regs * regs)
{
struct task_struct *tsk = current;
int usig = sig;
int ret;
/*
* translate the signal
*/
if (usig < 32 && tsk->exec_domain && tsk->exec_domain->signal_invmap)
usig = tsk->exec_domain->signal_invmap[usig];
/*
* Set up the stack frame
*/
if (ka->sa.sa_flags & SA_SIGINFO)
ret = setup_rt_frame(usig, ka, info, oldset, regs);
else
ret = setup_frame(usig, ka, oldset, regs);
/*
* Check that the resulting registers are actually sane.
*/
ret |= !valid_user_regs(regs);
if (ret == 0) {
if (ka->sa.sa_flags & SA_ONESHOT)
ka->sa.sa_handler = SIG_DFL;
if (!(ka->sa.sa_flags & SA_NODEFER)) {
spin_lock_irq(&tsk->sigmask_lock);
sigorsets(&tsk->blocked, &tsk->blocked,
&ka->sa.sa_mask);
sigaddset(&tsk->blocked, sig);
recalc_sigpending(tsk);
spin_unlock_irq(&tsk->sigmask_lock);
}
return;
}
if (sig == SIGSEGV)
ka->sa.sa_handler = SIG_DFL;
force_sig(SIGSEGV, tsk);
}
/*
* 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.
*/
asmlinkage int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
{
struct k_sigaction *ka;
siginfo_t info;
int single_stepping;
/*
* 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 0;
if (!oldset)
oldset = ¤t->blocked;
single_stepping = ptrace_cancel_bpt(current);
for (;;) {
unsigned long signr;
spin_lock_irq (¤t->sigmask_lock);
signr = dequeue_signal(¤t->blocked, &info);
spin_unlock_irq (¤t->sigmask_lock);
if (!signr)
break;
if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) {
/* Let the debugger run. */
current->exit_code = signr;
current->state = TASK_STOPPED;
notify_parent(current, SIGCHLD);
schedule();
single_stepping |= ptrace_cancel_bpt(current);
/* We're back. Did the debugger cancel the sig? */
if (!(signr = current->exit_code))
continue;
current->exit_code = 0;
/* The debugger continued. Ignore SIGSTOP. */
if (signr == SIGSTOP)
continue;
/* Update the siginfo structure. Is this good? */
if (signr != info.si_signo) {
info.si_signo = signr;
info.si_errno = 0;
info.si_code = SI_USER;
info.si_pid = current->p_pptr->pid;
info.si_uid = current->p_pptr->uid;
}
/* If the (new) signal is now blocked, requeue it. */
if (sigismember(¤t->blocked, signr)) {
send_sig_info(signr, &info, current);
continue;
}
}
ka = ¤t->sig->action[signr-1];
if (ka->sa.sa_handler == SIG_IGN) {
if (signr != SIGCHLD)
continue;
/* Check for SIGCHLD: it's special. */
while (sys_wait4(-1, NULL, WNOHANG, NULL) > 0)
/* nothing */;
continue;
}
if (ka->sa.sa_handler == SIG_DFL) {
int exit_code = signr;
/* Init gets no signals it doesn't want. */
if (current->pid == 1)
continue;
switch (signr) {
case SIGCONT: case SIGCHLD: case SIGWINCH:
continue;
case SIGTSTP: case SIGTTIN: case SIGTTOU:
if (is_orphaned_pgrp(current->pgrp))
continue;
/* FALLTHRU */
case SIGSTOP:
current->state = TASK_STOPPED;
current->exit_code = signr;
if (!(current->p_pptr->sig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
notify_parent(current, SIGCHLD);
schedule();
continue;
case SIGQUIT: case SIGILL: case SIGTRAP:
case SIGABRT: case SIGFPE: case SIGSEGV:
case SIGBUS: case SIGSYS: case SIGXCPU: case SIGXFSZ:
if (do_coredump(signr, regs))
exit_code |= 0x80;
/* FALLTHRU */
default:
sigaddset(¤t->pending.signal, signr);
recalc_sigpending(current);
current->flags |= PF_SIGNALED;
do_exit(exit_code);
/* NOTREACHED */
}
}
/* Are we from a system call? */
if (syscall) {
switch (regs->ARM_r0) {
case -ERESTARTNOHAND:
regs->ARM_r0 = -EINTR;
break;
case -ERESTARTSYS:
if (!(ka->sa.sa_flags & SA_RESTART)) {
regs->ARM_r0 = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
regs->ARM_r0 = regs->ARM_ORIG_r0;
regs->ARM_pc -= 4;
}
}
/* Whee! Actually deliver the signal. */
handle_signal(signr, ka, &info, oldset, regs);
if (single_stepping)
ptrace_set_bpt(current);
return 1;
}
if (syscall &&
(regs->ARM_r0 == -ERESTARTNOHAND ||
regs->ARM_r0 == -ERESTARTSYS ||
regs->ARM_r0 == -ERESTARTNOINTR)) {
regs->ARM_r0 = regs->ARM_ORIG_r0;
regs->ARM_pc -= 4;
}
if (single_stepping)
ptrace_set_bpt(current);
return 0;
}
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