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kernel-ark/arch/m32r/kernel/signal.c
Steven Rostedt 69be8f1896 [PATCH] convert signal handling of NODEFER to act like other Unix boxes. 
It has been reported that the way Linux handles NODEFER for signals is
not consistent with the way other Unix boxes handle it.  I've written a
program to test the behavior of how this flag affects signals and had
several reports from people who ran this on various Unix boxes,
confirming that Linux seems to be unique on the way this is handled.

The way NODEFER affects signals on other Unix boxes is as follows:

1) If NODEFER is set, other signals in sa_mask are still blocked.

2) If NODEFER is set and the signal is in sa_mask, then the signal is
still blocked. (Note: this is the behavior of all tested but Linux _and_
NetBSD 2.0 *).

The way NODEFER affects signals on Linux:

1) If NODEFER is set, other signals are _not_ blocked regardless of
sa_mask (Even NetBSD doesn't do this).

2) If NODEFER is set and the signal is in sa_mask, then the signal being
handled is not blocked.

The patch converts signal handling in all current Linux architectures to
the way most Unix boxes work.

Unix boxes that were tested:  DU4, AIX 5.2, Irix 6.5, NetBSD 2.0, SFU
3.5 on WinXP, AIX 5.3, Mac OSX, and of course Linux 2.6.13-rcX.

* NetBSD was the only other Unix to behave like Linux on point #2. The
main concern was brought up by point #1 which even NetBSD isn't like
Linux.  So with this patch, we leave NetBSD as the lonely one that
behaves differently here with #2.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-08-29 10:03:11 -07:00

436 lines
9.9 KiB
C
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/*
* linux/arch/m32r/kernel/signal.c
*
* Copyright (c) 2003 Hitoshi Yamamoto
*
* Taken from i386 version.
* Copyright (C) 1991, 1992 Linus Torvalds
*
* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
* 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
*/
#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/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/personality.h>
#include <linux/suspend.h>
#include <asm/cacheflush.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#define DEBUG_SIG 0
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
int do_signal(struct pt_regs *, sigset_t *);
asmlinkage int
sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize,
unsigned long r2, unsigned long r3, unsigned long r4,
unsigned long r5, unsigned long r6, 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.r0 = -EINTR;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (do_signal(&regs, &saveset))
return regs.r0;
}
}
asmlinkage int
sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
unsigned long r2, unsigned long r3, unsigned long r4,
unsigned long r5, unsigned long r6, struct pt_regs regs)
{
return do_sigaltstack(uss, uoss, regs.spu);
}
/*
* Do a signal return; undo the signal stack.
*/
struct rt_sigframe
{
int sig;
struct siginfo *pinfo;
void *puc;
struct siginfo info;
struct ucontext uc;
// struct _fpstate fpstate;
};
static int
restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
int *r0_p)
{
unsigned int err = 0;
/* Always make any pending restarted system calls return -EINTR */
current_thread_info()->restart_block.fn = do_no_restart_syscall;
#define COPY(x) err |= __get_user(regs->x, &sc->sc_##x)
COPY(r4);
COPY(r5);
COPY(r6);
COPY(pt_regs);
/* COPY(r0); Skip r0 */
COPY(r1);
COPY(r2);
COPY(r3);
COPY(r7);
COPY(r8);
COPY(r9);
COPY(r10);
COPY(r11);
COPY(r12);
#if defined(CONFIG_ISA_M32R2) && defined(CONFIG_ISA_DSP_LEVEL2)
COPY(acc0h);
COPY(acc0l);
COPY(acc1h);
COPY(acc1l);
#elif defined(CONFIG_ISA_M32R2) || defined(CONFIG_ISA_M32R)
COPY(acch);
COPY(accl);
#else
#error unknown isa configuration
#endif
COPY(psw);
COPY(bpc);
COPY(bbpsw);
COPY(bbpc);
COPY(spu);
COPY(fp);
COPY(lr);
COPY(spi);
#undef COPY
regs->syscall_nr = -1; /* disable syscall checks */
err |= __get_user(*r0_p, &sc->sc_r0);
return err;
}
asmlinkage int
sys_rt_sigreturn(unsigned long r0, unsigned long r1,
unsigned long r2, unsigned long r3, unsigned long r4,
unsigned long r5, unsigned long r6, struct pt_regs regs)
{
struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs.spu;
sigset_t set;
stack_t st;
int result;
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, &result))
goto badframe;
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, regs.spu);
return result;
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;
#define COPY(x) err |= __put_user(regs->x, &sc->sc_##x)
COPY(r4);
COPY(r5);
COPY(r6);
COPY(pt_regs);
COPY(r0);
COPY(r1);
COPY(r2);
COPY(r3);
COPY(r7);
COPY(r8);
COPY(r9);
COPY(r10);
COPY(r11);
COPY(r12);
#if defined(CONFIG_ISA_M32R2) && defined(CONFIG_ISA_DSP_LEVEL2)
COPY(acc0h);
COPY(acc0l);
COPY(acc1h);
COPY(acc1l);
#elif defined(CONFIG_ISA_M32R2) || defined(CONFIG_ISA_M32R)
COPY(acch);
COPY(accl);
#else
#error unknown isa configuration
#endif
COPY(psw);
COPY(bpc);
COPY(bbpsw);
COPY(bbpc);
COPY(spu);
COPY(fp);
COPY(lr);
COPY(spi);
#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)
{
/* This is the X/Open sanctioned signal stack switching. */
if (ka->sa.sa_flags & SA_ONSTACK) {
if (sas_ss_flags(sp) == 0)
sp = current->sas_ss_sp + current->sas_ss_size;
}
return (void __user *)((sp - frame_size) & -8ul);
}
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->spu, 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(signal, &frame->sig);
if (err)
goto give_sigsegv;
err |= __put_user(&frame->info, &frame->pinfo);
err |= __put_user(&frame->uc, &frame->puc);
err |= copy_siginfo_to_user(&frame->info, info);
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(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
err |= __put_user(sas_ss_flags(regs->spu),
&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));
if (err)
goto give_sigsegv;
/* Set up to return from userspace. */
regs->lr = (unsigned long)ka->sa.sa_restorer;
/* Set up registers for signal handler */
regs->spu = (unsigned long)frame;
regs->r0 = signal; /* Arg for signal handler */
regs->r1 = (unsigned long)&frame->info;
regs->r2 = (unsigned long)&frame->uc;
regs->bpc = (unsigned long)ka->sa.sa_handler;
set_fs(USER_DS);
#if DEBUG_SIG
printk("SIG deliver (%s:%d): sp=%p pc=%p\n",
current->comm, current->pid, frame, regs->pc);
#endif
return;
give_sigsegv:
force_sigsegv(sig, current);
}
/*
* 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)
{
unsigned short inst;
/* Are we from a system call? */
if (regs->syscall_nr >= 0) {
/* If so, check system call restarting.. */
switch (regs->r0) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
regs->r0 = -EINTR;
break;
case -ERESTARTSYS:
if (!(ka->sa.sa_flags & SA_RESTART)) {
regs->r0 = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
regs->r0 = regs->orig_r0;
inst = *(unsigned short *)(regs->bpc - 2);
if ((inst & 0xfff0) == 0x10f0) /* trap ? */
regs->bpc -= 2;
else
regs->bpc -= 4;
}
}
/* Set up the stack frame */
setup_rt_frame(sig, ka, info, oldset, regs);
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);
}
/*
* 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)
{
siginfo_t info;
int signr;
struct k_sigaction ka;
unsigned short inst;
/*
* 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) {
/* Reenable any watchpoints before delivering the
* signal to user space. The processor register will
* have been cleared if the watchpoint triggered
* inside the kernel.
*/
/* Whee! Actually deliver the signal. */
handle_signal(signr, &ka, &info, oldset, regs);
return 1;
}
no_signal:
/* Did we come from a system call? */
if (regs->syscall_nr >= 0) {
/* Restart the system call - no handlers present */
if (regs->r0 == -ERESTARTNOHAND ||
regs->r0 == -ERESTARTSYS ||
regs->r0 == -ERESTARTNOINTR) {
regs->r0 = regs->orig_r0;
inst = *(unsigned short *)(regs->bpc - 2);
if ((inst & 0xfff0) == 0x10f0) /* trap ? */
regs->bpc -= 2;
else
regs->bpc -= 4;
}
if (regs->r0 == -ERESTART_RESTARTBLOCK){
regs->r0 = regs->orig_r0;
regs->r7 = __NR_restart_syscall;
inst = *(unsigned short *)(regs->bpc - 2);
if ((inst & 0xfff0) == 0x10f0) /* trap ? */
regs->bpc -= 2;
else
regs->bpc -= 4;
}
}
return 0;
}
/*
* notification of userspace execution resumption
* - triggered by current->work.notify_resume
*/
void do_notify_resume(struct pt_regs *regs, sigset_t *oldset,
__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(regs,oldset);
clear_thread_flag(TIF_IRET);
}
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