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8efc0ab50e
linux/arch/frv/kernel/signal.c
David Howells 8efc0ab50e [PATCH] frv: fix signal handling 
The attached patch makes FRV signal handling work properly:

 (1) After do_notify_resume() has been called, the work flags must be checked
     again (there may be another signal to deliver or the process might require
     rescheduling for instance).

 (2) After the signal frame is set up on the userspace stack, ptrace() should
     be given an opportunity to single-step into the signal handler.

 (3) The error state from setting up a signal frame should be passed back up
     the call chain.

 (4) The segfault handler shouldn't be preemptively reset in the arch if we
     fail to deliver a SEGV signal: force_sig() will take care of that.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:33 -08:00

603 lines
15 KiB
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/* signal.c: FRV specific bits of signal handling
*
* Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
* - Derived from arch/m68k/kernel/signal.c
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/personality.h>
#include <linux/suspend.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/cacheflush.h>
#define DEBUG_SIG 0
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
struct fdpic_func_descriptor {
unsigned long text;
unsigned long GOT;
};
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(int history0, int history1, old_sigset_t mask)
{
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);
__frame->gr8 = -EINTR;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (do_signal(__frame, &saveset))
/* return the signal number as the return value of this function
* - this is an utterly evil hack. syscalls should not invoke do_signal()
* as entry.S sets regs->gr8 to the return value of the system call
* - we can't just use sigpending() as we'd have to discard SIG_IGN signals
* and call waitpid() if SIGCHLD needed discarding
* - this only works on the i386 because it passes arguments to the signal
* handler on the stack, and the return value in EAX is effectively
* discarded
*/
return __frame->gr8;
}
}
asmlinkage int sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize)
{
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);
__frame->gr8 = -EINTR;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (do_signal(__frame, &saveset))
/* return the signal number as the return value of this function
* - this is an utterly evil hack. syscalls should not invoke do_signal()
* as entry.S sets regs->gr8 to the return value of the system call
* - we can't just use sigpending() as we'd have to discard SIG_IGN signals
* and call waitpid() if SIGCHLD needed discarding
* - this only works on the i386 because it passes arguments to the signal
* handler on the stack, and the return value in EAX is effectively
* discarded
*/
return __frame->gr8;
}
}
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)
{
return do_sigaltstack(uss, uoss, __frame->sp);
}
/*
* Do a signal return; undo the signal stack.
*/
struct sigframe
{
void (*pretcode)(void);
int sig;
struct sigcontext sc;
unsigned long extramask[_NSIG_WORDS-1];
uint32_t retcode[2];
};
struct rt_sigframe
{
void (*pretcode)(void);
int sig;
struct siginfo *pinfo;
void *puc;
struct siginfo info;
struct ucontext uc;
uint32_t retcode[2];
};
static int restore_sigcontext(struct sigcontext __user *sc, int *_gr8)
{
struct user_context *user = current->thread.user;
unsigned long tbr, psr;
tbr = user->i.tbr;
psr = user->i.psr;
if (copy_from_user(user, &sc->sc_context, sizeof(sc->sc_context)))
goto badframe;
user->i.tbr = tbr;
user->i.psr = psr;
restore_user_regs(user);
user->i.syscallno = -1; /* disable syscall checks */
*_gr8 = user->i.gr[8];
return 0;
badframe:
return 1;
}
asmlinkage int sys_sigreturn(void)
{
struct sigframe __user *frame = (struct sigframe __user *) __frame->sp;
sigset_t set;
int gr8;
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
if (__get_user(set.sig[0], &frame->sc.sc_oldmask))
goto badframe;
if (_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(&frame->sc, &gr8))
goto badframe;
return gr8;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
asmlinkage int sys_rt_sigreturn(void)
{
struct rt_sigframe __user *frame = (struct rt_sigframe __user *) __frame->sp;
sigset_t set;
int gr8;
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(&frame->uc.uc_mcontext, &gr8))
goto badframe;
if (do_sigaltstack(&frame->uc.uc_stack, NULL, __frame->sp) == -EFAULT)
goto badframe;
return gr8;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
/*
* Set up a signal frame
*/
static int setup_sigcontext(struct sigcontext __user *sc, unsigned long mask)
{
save_user_regs(current->thread.user);
if (copy_to_user(&sc->sc_context, current->thread.user, sizeof(sc->sc_context)) != 0)
goto badframe;
/* non-iBCS2 extensions.. */
if (__put_user(mask, &sc->sc_oldmask) < 0)
goto badframe;
return 0;
badframe:
return 1;
}
/*****************************************************************************/
/*
* Determine which stack to use..
*/
static inline void __user *get_sigframe(struct k_sigaction *ka,
struct pt_regs *regs,
size_t frame_size)
{
unsigned long sp;
/* Default to using normal stack */
sp = regs->sp;
/* This is the X/Open sanctioned signal stack switching. */
if (ka->sa.sa_flags & SA_ONSTACK) {
if (! on_sig_stack(sp))
sp = current->sas_ss_sp + current->sas_ss_size;
}
return (void __user *) ((sp - frame_size) & ~7UL);
} /* end get_sigframe() */
/*****************************************************************************/
/*
*
*/
static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
struct pt_regs *regs)
{
struct sigframe __user *frame;
int rsig;
frame = get_sigframe(ka, regs, sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
goto give_sigsegv;
rsig = sig;
if (sig < 32 &&
__current_thread_info->exec_domain &&
__current_thread_info->exec_domain->signal_invmap)
rsig = __current_thread_info->exec_domain->signal_invmap[sig];
if (__put_user(rsig, &frame->sig) < 0)
goto give_sigsegv;
if (setup_sigcontext(&frame->sc, set->sig[0]))
goto give_sigsegv;
if (_NSIG_WORDS > 1) {
if (__copy_to_user(frame->extramask, &set->sig[1],
sizeof(frame->extramask)))
goto give_sigsegv;
}
/* Set up to return from userspace. If provided, use a stub
* already in userspace. */
if (ka->sa.sa_flags & SA_RESTORER) {
if (__put_user(ka->sa.sa_restorer, &frame->pretcode) < 0)
goto give_sigsegv;
}
else {
/* Set up the following code on the stack:
* setlos #__NR_sigreturn,gr7
* tira gr0,0
*/
if (__put_user((void (*)(void))frame->retcode, &frame->pretcode) ||
__put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) ||
__put_user(0xc0700000, &frame->retcode[1]))
goto give_sigsegv;
flush_icache_range((unsigned long) frame->retcode,
(unsigned long) (frame->retcode + 2));
}
/* set up registers for signal handler */
regs->sp = (unsigned long) frame;
regs->lr = (unsigned long) &frame->retcode;
regs->gr8 = sig;
if (get_personality & FDPIC_FUNCPTRS) {
struct fdpic_func_descriptor __user *funcptr =
(struct fdpic_func_descriptor *) ka->sa.sa_handler;
__get_user(regs->pc, &funcptr->text);
__get_user(regs->gr15, &funcptr->GOT);
} else {
regs->pc = (unsigned long) ka->sa.sa_handler;
regs->gr15 = 0;
}
set_fs(USER_DS);
/* the tracer may want to single-step inside the handler */
if (test_thread_flag(TIF_SINGLESTEP))
ptrace_notify(SIGTRAP);
#if DEBUG_SIG
printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
sig, current->comm, current->pid, frame, regs->pc,
frame->pretcode);
#endif
return 1;
give_sigsegv:
force_sig(SIGSEGV, current);
return 0;
} /* end setup_frame() */
/*****************************************************************************/
/*
*
*/
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 rsig;
frame = get_sigframe(ka, regs, sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
goto give_sigsegv;
rsig = sig;
if (sig < 32 &&
__current_thread_info->exec_domain &&
__current_thread_info->exec_domain->signal_invmap)
rsig = __current_thread_info->exec_domain->signal_invmap[sig];
if (__put_user(rsig, &frame->sig) ||
__put_user(&frame->info, &frame->pinfo) ||
__put_user(&frame->uc, &frame->puc))
goto give_sigsegv;
if (copy_siginfo_to_user(&frame->info, info))
goto give_sigsegv;
/* Create the ucontext. */
if (__put_user(0, &frame->uc.uc_flags) ||
__put_user(0, &frame->uc.uc_link) ||
__put_user((void*)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
__put_user(sas_ss_flags(regs->sp), &frame->uc.uc_stack.ss_flags) ||
__put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size))
goto give_sigsegv;
if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0]))
goto give_sigsegv;
if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
goto give_sigsegv;
/* Set up to return from userspace. If provided, use a stub
* already in userspace. */
if (ka->sa.sa_flags & SA_RESTORER) {
if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
goto give_sigsegv;
}
else {
/* Set up the following code on the stack:
* setlos #__NR_sigreturn,gr7
* tira gr0,0
*/
if (__put_user((void (*)(void))frame->retcode, &frame->pretcode) ||
__put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) ||
__put_user(0xc0700000, &frame->retcode[1]))
goto give_sigsegv;
flush_icache_range((unsigned long) frame->retcode,
(unsigned long) (frame->retcode + 2));
}
/* Set up registers for signal handler */
regs->sp = (unsigned long) frame;
regs->lr = (unsigned long) &frame->retcode;
regs->gr8 = sig;
regs->gr9 = (unsigned long) &frame->info;
if (get_personality & FDPIC_FUNCPTRS) {
struct fdpic_func_descriptor *funcptr =
(struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
__get_user(regs->pc, &funcptr->text);
__get_user(regs->gr15, &funcptr->GOT);
} else {
regs->pc = (unsigned long) ka->sa.sa_handler;
regs->gr15 = 0;
}
set_fs(USER_DS);
/* the tracer may want to single-step inside the handler */
if (test_thread_flag(TIF_SINGLESTEP))
ptrace_notify(SIGTRAP);
#if DEBUG_SIG
printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
sig, current->comm, current->pid, frame, regs->pc,
frame->pretcode);
#endif
return 1;
give_sigsegv:
force_sig(SIGSEGV, current);
return 0;
} /* end setup_rt_frame() */
/*****************************************************************************/
/*
* OK, we're invoking a handler
*/
static int handle_signal(unsigned long sig, siginfo_t *info,
struct k_sigaction *ka, sigset_t *oldset,
struct pt_regs *regs)
{
int ret;
/* Are we from a system call? */
if (in_syscall(regs)) {
/* If so, check system call restarting.. */
switch (regs->gr8) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
regs->gr8 = -EINTR;
break;
case -ERESTARTSYS:
if (!(ka->sa.sa_flags & SA_RESTART)) {
regs->gr8 = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
regs->gr8 = regs->orig_gr8;
regs->pc -= 4;
}
}
/* Set up the stack frame */
if (ka->sa.sa_flags & SA_SIGINFO)
ret = setup_rt_frame(sig, ka, info, oldset, regs);
else
ret = setup_frame(sig, ka, oldset, regs);
if (ret) {
spin_lock_irq(&current->sighand->siglock);
sigorsets(&current->blocked, &current->blocked,
&ka->sa.sa_mask);
if (!(ka->sa.sa_flags & SA_NODEFER))
sigaddset(&current->blocked, sig);
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
}
return ret;
} /* end handle_signal() */
/*****************************************************************************/
/*
* 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.
*/
int do_signal(struct pt_regs *regs, sigset_t *oldset)
{
struct k_sigaction ka;
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 1;
if (try_to_freeze())
goto no_signal;
if (!oldset)
oldset = &current->blocked;
signr = get_signal_to_deliver(&info, &ka, regs, NULL);
if (signr > 0)
return handle_signal(signr, &info, &ka, oldset, regs);
no_signal:
/* Did we come from a system call? */
if (regs->syscallno >= 0) {
/* Restart the system call - no handlers present */
if (regs->gr8 == -ERESTARTNOHAND ||
regs->gr8 == -ERESTARTSYS ||
regs->gr8 == -ERESTARTNOINTR) {
regs->gr8 = regs->orig_gr8;
regs->pc -= 4;
}
if (regs->gr8 == -ERESTART_RESTARTBLOCK){
regs->gr8 = __NR_restart_syscall;
regs->pc -= 4;
}
}
return 0;
} /* end do_signal() */
/*****************************************************************************/
/*
* notification of userspace execution resumption
* - triggered by current->work.notify_resume
*/
asmlinkage void do_notify_resume(__u32 thread_info_flags)
{
/* pending single-step? */
if (thread_info_flags & _TIF_SINGLESTEP)
clear_thread_flag(TIF_SINGLESTEP);
/* deal with pending signal delivery */
if (thread_info_flags & _TIF_SIGPENDING)
do_signal(__frame, NULL);
} /* end do_notify_resume() */
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