/*
* Copyright (C) 2004-2006 Atmel Corporation
*
* Based on linux/arch/sh/kernel/signal.c
* Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
* Copyright (C) 1991, 1992 Linus Torvalds
*
* 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/sched.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/tracehook.h>
#include <asm/uaccess.h>
#include <asm/ucontext.h>
#include <asm/syscalls.h>
struct rt_sigframe
{
struct siginfo info;
struct ucontext uc;
unsigned long retcode;
};
static int
restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
{
int err = 0;
#define COPY(x) err |= __get_user(regs->x, &sc->x)
COPY(sr);
COPY(pc);
COPY(lr);
COPY(sp);
COPY(r12);
COPY(r11);
COPY(r10);
COPY(r9);
COPY(r8);
COPY(r7);
COPY(r6);
COPY(r5);
COPY(r4);
COPY(r3);
COPY(r2);
COPY(r1);
COPY(r0);
#undef COPY
/*
* Don't allow anyone to pretend they're running in supervisor
* mode or something...
*/
err |= !valid_user_regs(regs);
return err;
}
asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
{
struct rt_sigframe __user *frame;
sigset_t set;
/* Always make any pending restarted system calls return -EINTR */
current_thread_info()->restart_block.fn = do_no_restart_syscall;
frame = (struct rt_sigframe __user *)regs->sp;
pr_debug("SIG return: frame = %p\n", frame);
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
goto badframe;
set_current_blocked(&set);
if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
goto badframe;
if (restore_altstack(&frame->uc.uc_stack))
goto badframe;
pr_debug("Context restored: pc = %08lx, lr = %08lx, sp = %08lx\n",
regs->pc, regs->lr, regs->sp);
return regs->r12;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
static int
setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
{
int err = 0;
#define COPY(x) err |= __put_user(regs->x, &sc->x)
COPY(sr);
COPY(pc);
COPY(lr);
COPY(sp);
COPY(r12);
COPY(r11);
COPY(r10);
COPY(r9);
COPY(r8);
COPY(r7);
COPY(r6);
COPY(r5);
COPY(r4);
COPY(r3);
COPY(r2);
COPY(r1);
COPY(r0);
#undef COPY
return err;
}
static inline void __user *
get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
{
unsigned long sp = regs->sp;
if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
sp = current->sas_ss_sp + current->sas_ss_size;
return (void __user *)((sp - framesize) & ~3);
}
static int
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;
frame = get_sigframe(ka, regs, sizeof(*frame));
err = -EFAULT;
if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
goto out;
/*
* Set up the return code:
*
* mov r8, __NR_rt_sigreturn
* scall
*
* Note: This will blow up since we're using a non-executable
* stack. Better use SA_RESTORER.
*/
#if __NR_rt_sigreturn > 127
# error __NR_rt_sigreturn must be < 127 to fit in a short mov
#endif
err = __put_user(0x3008d733 | (__NR_rt_sigreturn << 20),
&frame->retcode);
err |= copy_siginfo_to_user(&frame->info, info);
/* Set up the ucontext */
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(NULL, &frame->uc.uc_link);
err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
err |= setup_sigcontext(&frame->uc.uc_mcontext, regs);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
if (err)
goto out;
regs->r12 = sig;
regs->r11 = (unsigned long) &frame->info;
regs->r10 = (unsigned long) &frame->uc;
regs->sp = (unsigned long) frame;
if (ka->sa.sa_flags & SA_RESTORER)
regs->lr = (unsigned long)ka->sa.sa_restorer;
else {
printk(KERN_NOTICE "[%s:%d] did not set SA_RESTORER\n",
current->comm, current->pid);
regs->lr = (unsigned long) &frame->retcode;
}
pr_debug("SIG deliver [%s:%d]: sig=%d sp=0x%lx pc=0x%lx->0x%p lr=0x%lx\n",
current->comm, current->pid, sig, regs->sp,
regs->pc, ka->sa.sa_handler, regs->lr);
regs->pc = (unsigned long) ka->sa.sa_handler;
out:
return err;
}
static inline void setup_syscall_restart(struct pt_regs *regs)
{
if (regs->r12 == -ERESTART_RESTARTBLOCK)
regs->r8 = __NR_restart_syscall;
else
regs->r12 = regs->r12_orig;
regs->pc -= 2;
}
static inline void
handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
struct pt_regs *regs, int syscall)
{
int ret;
/*
* Set up the stack frame
*/
ret = setup_rt_frame(sig, ka, info, sigmask_to_save(), regs);
/*
* Check that the resulting registers are sane
*/
ret |= !valid_user_regs(regs);
/*
* Block the signal if we were successful.
*/
if (ret != 0)
force_sigsegv(sig, current);
else
signal_delivered(sig, info, ka, regs, 0);
}
/*
* 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.
*/
static void do_signal(struct pt_regs *regs, int syscall)
{
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;
signr = get_signal_to_deliver(&info, &ka, regs, NULL);
if (syscall) {
switch (regs->r12) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
if (signr > 0) {
regs->r12 = -EINTR;
break;
}
/* fall through */
case -ERESTARTSYS:
if (signr > 0 && !(ka.sa.sa_flags & SA_RESTART)) {
regs->r12 = -EINTR;
break;
}
/* fall through */
case -ERESTARTNOINTR:
setup_syscall_restart(regs);
}
}
if (signr == 0) {
/* No signal to deliver -- put the saved sigmask back */
restore_saved_sigmask();
return;
}
handle_signal(signr, &ka, &info, regs, syscall);
}
asmlinkage void do_notify_resume(struct pt_regs *regs, struct thread_info *ti)
{
int syscall = 0;
if ((sysreg_read(SR) & MODE_MASK) == MODE_SUPERVISOR)
syscall = 1;
if (ti->flags & _TIF_SIGPENDING)
do_signal(regs, syscall);
if (ti->flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
}