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linux_dsm_epyc7002/arch/v850/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

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/*
* arch/v850/kernel/signal.c -- Signal handling
*
* Copyright (C) 2001,02,03 NEC Electronics Corporation
* Copyright (C) 2001,02,03 Miles Bader <miles@gnu.org>
* Copyright (C) 1999,2000,2002 Niibe Yutaka & Kaz Kojima
* Copyright (C) 1991,1992 Linus Torvalds
*
* This file is subject to the terms and conditions of the GNU General
* Public License. See the file COPYING in the main directory of this
* archive for more details.
*
* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
*
* This file was derived from the sh version, arch/sh/kernel/signal.c
*/
#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/stddef.h>
#include <linux/personality.h>
#include <linux/tty.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/thread_info.h>
#include <asm/cacheflush.h>
#define DEBUG_SIG 0
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
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(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->gpr[GPR_RVAL] = -EINTR;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (do_signal(regs, &saveset))
return -EINTR;
}
}
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->gpr[GPR_RVAL] = -EINTR;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (do_signal(regs, &saveset))
return -EINTR;
}
}
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;
}
asmlinkage int
sys_sigaltstack(const stack_t *uss, stack_t *uoss,
struct pt_regs *regs)
{
return do_sigaltstack(uss, uoss, regs->gpr[GPR_SP]);
}
/*
* Do a signal return; undo the signal stack.
*/
struct sigframe
{
struct sigcontext sc;
unsigned long extramask[_NSIG_WORDS-1];
unsigned long tramp[2]; /* signal trampoline */
};
struct rt_sigframe
{
struct siginfo info;
struct ucontext uc;
unsigned long tramp[2]; /* signal trampoline */
};
static int
restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc, int *rval_p)
{
unsigned int err = 0;
#define COPY(x) err |= __get_user(regs->x, &sc->regs.x)
COPY(gpr[0]); COPY(gpr[1]); COPY(gpr[2]); COPY(gpr[3]);
COPY(gpr[4]); COPY(gpr[5]); COPY(gpr[6]); COPY(gpr[7]);
COPY(gpr[8]); COPY(gpr[9]); COPY(gpr[10]); COPY(gpr[11]);
COPY(gpr[12]); COPY(gpr[13]); COPY(gpr[14]); COPY(gpr[15]);
COPY(gpr[16]); COPY(gpr[17]); COPY(gpr[18]); COPY(gpr[19]);
COPY(gpr[20]); COPY(gpr[21]); COPY(gpr[22]); COPY(gpr[23]);
COPY(gpr[24]); COPY(gpr[25]); COPY(gpr[26]); COPY(gpr[27]);
COPY(gpr[28]); COPY(gpr[29]); COPY(gpr[30]); COPY(gpr[31]);
COPY(pc); COPY(psw);
COPY(ctpc); COPY(ctpsw); COPY(ctbp);
#undef COPY
return err;
}
asmlinkage int sys_sigreturn(struct pt_regs *regs)
{
struct sigframe *frame = (struct sigframe *)regs->gpr[GPR_SP];
sigset_t set;
int rval;
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, &rval))
goto badframe;
return rval;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
{
struct rt_sigframe *frame = (struct rt_sigframe *)regs->gpr[GPR_SP];
sigset_t set;
stack_t st;
int rval;
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, &rval))
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->gpr[GPR_SP]);
return rval;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
/*
* Set up a signal frame.
*/
static int
setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,
unsigned long mask)
{
int err = 0;
#define COPY(x) err |= __put_user(regs->x, &sc->regs.x)
COPY(gpr[0]); COPY(gpr[1]); COPY(gpr[2]); COPY(gpr[3]);
COPY(gpr[4]); COPY(gpr[5]); COPY(gpr[6]); COPY(gpr[7]);
COPY(gpr[8]); COPY(gpr[9]); COPY(gpr[10]); COPY(gpr[11]);
COPY(gpr[12]); COPY(gpr[13]); COPY(gpr[14]); COPY(gpr[15]);
COPY(gpr[16]); COPY(gpr[17]); COPY(gpr[18]); COPY(gpr[19]);
COPY(gpr[20]); COPY(gpr[21]); COPY(gpr[22]); COPY(gpr[23]);
COPY(gpr[24]); COPY(gpr[25]); COPY(gpr[26]); COPY(gpr[27]);
COPY(gpr[28]); COPY(gpr[29]); COPY(gpr[30]); COPY(gpr[31]);
COPY(pc); COPY(psw);
COPY(ctpc); COPY(ctpsw); COPY(ctbp);
#undef COPY
err |= __put_user(mask, &sc->oldmask);
return err;
}
/*
* Determine which stack to use..
*/
static inline void *
get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
{
/* Default to using normal stack */
unsigned long sp = regs->gpr[GPR_SP];
if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! on_sig_stack(sp))
sp = current->sas_ss_sp + current->sas_ss_size;
return (void *)((sp - frame_size) & -8UL);
}
static void setup_frame(int sig, struct k_sigaction *ka,
sigset_t *set, struct pt_regs *regs)
{
struct sigframe *frame;
int err = 0;
int signal;
frame = get_sigframe(ka, regs, 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 |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
if (_NSIG_WORDS > 1) {
err |= __copy_to_user(frame->extramask, &set->sig[1],
sizeof(frame->extramask));
}
/* Set up to return from userspace. If provided, use a stub
already in userspace. */
if (ka->sa.sa_flags & SA_RESTORER) {
regs->gpr[GPR_LP] = (unsigned long) ka->sa.sa_restorer;
} else {
/* Note, these encodings are _little endian_! */
/* addi __NR_sigreturn, r0, r12 */
err |= __put_user(0x6600 | (__NR_sigreturn << 16),
frame->tramp + 0);
/* trap 0 */
err |= __put_user(0x010007e0,
frame->tramp + 1);
regs->gpr[GPR_LP] = (unsigned long)frame->tramp;
flush_cache_sigtramp (regs->gpr[GPR_LP]);
}
if (err)
goto give_sigsegv;
/* Set up registers for signal handler. */
regs->pc = (v850_reg_t) ka->sa.sa_handler;
regs->gpr[GPR_SP] = (v850_reg_t)frame;
/* Signal handler args: */
regs->gpr[GPR_ARG0] = signal; /* arg 0: signum */
regs->gpr[GPR_ARG1] = (v850_reg_t)&frame->sc;/* arg 1: sigcontext */
set_fs(USER_DS);
#if DEBUG_SIG
printk("SIG deliver (%s:%d): sp=%p pc=%08lx ra=%08lx\n",
current->comm, current->pid, frame, regs->pc, );
#endif
return;
give_sigsegv:
force_sigsegv(sig, current);
}
static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set, struct pt_regs *regs)
{
struct rt_sigframe *frame;
int err = 0;
int signal;
frame = get_sigframe(ka, regs, 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 |= copy_siginfo_to_user(&frame->info, info);
/* Create the ucontext. */
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(0, &frame->uc.uc_link);
err |= __put_user((void *)current->sas_ss_sp,
&frame->uc.uc_stack.ss_sp);
err |= __put_user(sas_ss_flags(regs->gpr[GPR_SP]),
&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));
/* Set up to return from userspace. If provided, use a stub
already in userspace. */
if (ka->sa.sa_flags & SA_RESTORER) {
regs->gpr[GPR_LP] = (unsigned long) ka->sa.sa_restorer;
} else {
/* Note, these encodings are _little endian_! */
/* addi __NR_sigreturn, r0, r12 */
err |= __put_user(0x6600 | (__NR_sigreturn << 16),
frame->tramp + 0);
/* trap 0 */
err |= __put_user(0x010007e0,
frame->tramp + 1);
regs->gpr[GPR_LP] = (unsigned long)frame->tramp;
flush_cache_sigtramp (regs->gpr[GPR_LP]);
}
if (err)
goto give_sigsegv;
/* Set up registers for signal handler. */
regs->pc = (v850_reg_t) ka->sa.sa_handler;
regs->gpr[GPR_SP] = (v850_reg_t)frame;
/* Signal handler args: */
regs->gpr[GPR_ARG0] = signal; /* arg 0: signum */
regs->gpr[GPR_ARG1] = (v850_reg_t)&frame->info; /* arg 1: siginfo */
regs->gpr[GPR_ARG2] = (v850_reg_t)&frame->uc; /* arg 2: ucontext */
set_fs(USER_DS);
#if DEBUG_SIG
printk("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
current->comm, current->pid, frame, regs->pc, regs->pr);
#endif
return;
give_sigsegv:
force_sigsegv(sig, current);
}
/*
* OK, we're invoking a handler
*/
static void
handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
sigset_t *oldset, struct pt_regs * regs)
{
/* Are we from a system call? */
if (PT_REGS_SYSCALL (regs)) {
/* If so, check system call restarting.. */
switch (regs->gpr[GPR_RVAL]) {
case -ERESTART_RESTARTBLOCK:
current_thread_info()->restart_block.fn =
do_no_restart_syscall;
/* fall through */
case -ERESTARTNOHAND:
regs->gpr[GPR_RVAL] = -EINTR;
break;
case -ERESTARTSYS:
if (!(ka->sa.sa_flags & SA_RESTART)) {
regs->gpr[GPR_RVAL] = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
regs->gpr[12] = PT_REGS_SYSCALL (regs);
regs->pc -= 4; /* Size of `trap 0' insn. */
}
PT_REGS_SET_SYSCALL (regs, 0);
}
/* Set up the stack frame */
if (ka->sa.sa_flags & SA_SIGINFO)
setup_rt_frame(sig, ka, info, oldset, regs);
else
setup_frame(sig, ka, 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.
*
* 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.
*/
int do_signal(struct pt_regs *regs, sigset_t *oldset)
{
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 1;
if (!oldset)
oldset = &current->blocked;
signr = get_signal_to_deliver(&info, &ka, regs, NULL);
if (signr > 0) {
/* Whee! Actually deliver the signal. */
handle_signal(signr, &info, &ka, oldset, regs);
return 1;
}
/* Did we come from a system call? */
if (PT_REGS_SYSCALL (regs)) {
int rval = (int)regs->gpr[GPR_RVAL];
/* Restart the system call - no handlers present */
if (rval == -ERESTARTNOHAND
|| rval == -ERESTARTSYS
|| rval == -ERESTARTNOINTR)
{
regs->gpr[12] = PT_REGS_SYSCALL (regs);
regs->pc -= 4; /* Size of `trap 0' insn. */
}
else if (rval == -ERESTART_RESTARTBLOCK) {
regs->gpr[12] = __NR_restart_syscall;
regs->pc -= 4; /* Size of `trap 0' insn. */
}
}
return 0;
}
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