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linux/arch/arm26/kernel/signal.c

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/*
* linux/arch/arm26/kernel/signal.c
*
* Copyright (C) 1995-2002 Russell King
* Copyright (C) 2003 Ian Molton (ARM26)
*
* FIXME!!! This is probably very broken (13/05/2003)
*
* 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/personality.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/elf.h>
#include <asm/pgalloc.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/unistd.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))
static int do_signal(sigset_t *oldset, struct pt_regs * regs, int syscall);
/*
* 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(&current->sighand->siglock);
saveset = current->blocked;
siginitset(&current->blocked, mask);
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
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(&current->sighand->siglock);
saveset = current->blocked;
current->blocked = newset;
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
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 (!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;
}
/*
* 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);
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 (!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(&current->sighand->siglock);
current->blocked = set;
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
if (restore_sigcontext(regs, &frame->sc))
goto badframe;
/* Send SIGTRAP if we're single-stepping */
if (current->ptrace & PT_SINGLESTEP) {
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 (!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(&current->sighand->siglock);
current->blocked = set;
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
goto badframe;
/* Send SIGTRAP if we're single-stepping */
if (current->ptrace & PT_SINGLESTEP) {
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);
__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;
if (ka->sa.sa_flags & SA_RESTORER) {
retcode = (unsigned long)ka->sa.sa_restorer;
} else {
if (__put_user((ka->sa.sa_flags & SA_SIGINFO)?SWI_SYS_RT_SIGRETURN:SWI_SYS_SIGRETURN, rc))
return 1;
retcode = ((unsigned long)rc);
}
regs->ARM_r0 = usig;
regs->ARM_sp = (unsigned long)frame;
regs->ARM_lr = retcode;
regs->ARM_pc = handler & ~3;
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;
}
static inline void restart_syscall(struct pt_regs *regs)
{
regs->ARM_r0 = regs->ARM_ORIG_r0;
regs->ARM_pc -= 4;
}
/*
* OK, we're invoking a handler
*/
static void
handle_signal(unsigned long sig, siginfo_t *info, sigset_t *oldset,
struct pt_regs * regs, int syscall)
{
struct thread_info *thread = current_thread_info();
struct task_struct *tsk = current;
struct k_sigaction *ka = &tsk->sighand->action[sig-1];
int usig = sig;
int ret;
/*
* If we were from a system call, check for system call restarting...
*/
if (syscall) {
switch (regs->ARM_r0) {
case -ERESTART_RESTARTBLOCK:
current_thread_info()->restart_block.fn =
do_no_restart_syscall;
case -ERESTARTNOHAND:
regs->ARM_r0 = -EINTR;
break;
case -ERESTARTSYS:
if (!(ka->sa.sa_flags & SA_RESTART)) {
regs->ARM_r0 = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
restart_syscall(regs);
}
}
/*
* translate the signal
*/
if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
usig = thread->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->sighand->siglock);
sigorsets(&tsk->blocked, &tsk->blocked,
&ka->sa.sa_mask);
sigaddset(&tsk->blocked, sig);
recalc_sigpending();
spin_unlock_irq(&tsk->sighand->siglock);
}
return;
}
force_sigsegv(sig, 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.
*/
static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
{
siginfo_t info;
int signr;
/*
* 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 (current->ptrace & PT_SINGLESTEP)
ptrace_cancel_bpt(current);
signr = get_signal_to_deliver(&info, regs, NULL);
if (signr > 0) {
handle_signal(signr, &info, oldset, regs, syscall);
if (current->ptrace & PT_SINGLESTEP)
ptrace_set_bpt(current);
return 1;
}
/*
* No signal to deliver to the process - restart the syscall.
*/
if (syscall) {
if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) {
u32 *usp;
regs->ARM_sp -= 12;
usp = (u32 *)regs->ARM_sp;
put_user(regs->ARM_pc, &usp[0]);
/* swi __NR_restart_syscall */
put_user(0xef000000 | __NR_restart_syscall, &usp[1]);
/* ldr pc, [sp], #12 */
// FIXME!!! is #12 correct there?
put_user(0xe49df00c, &usp[2]);
regs->ARM_pc = regs->ARM_sp + 4;
}
if (regs->ARM_r0 == -ERESTARTNOHAND ||
regs->ARM_r0 == -ERESTARTSYS ||
regs->ARM_r0 == -ERESTARTNOINTR) {
restart_syscall(regs);
}
}
if (current->ptrace & PT_SINGLESTEP)
ptrace_set_bpt(current);
return 0;
}
asmlinkage void
do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
{
if (thread_flags & _TIF_SIGPENDING)
do_signal(&current->blocked, regs, syscall);
}
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