linux/arch/ia64/kernel/signal.c
Matt Fleming 7a076e4ff0 ia64: use set_current_blocked() and block_sigmask()
As described in e6fa16ab ("signal: sigprocmask() should do
retarget_shared_pending()") the modification of current->blocked is
incorrect as we need to check whether the signal we're about to block is
pending in the shared queue.

Also, use the new helper function introduced in commit 5e6292c0f2
("signal: add block_sigmask() for adding sigmask to current->blocked")
which centralises the code for updating current->blocked after
successfully delivering a signal and reduces the amount of duplicate code
across architectures.  In the past some architectures got this code wrong,
so using this helper function should stop that from happening again.

Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-05-21 23:52:34 -04:00

546 lines
18 KiB
C

/*
* Architecture-specific signal handling support.
*
* Copyright (C) 1999-2004 Hewlett-Packard Co
* David Mosberger-Tang <davidm@hpl.hp.com>
*
* Derived from i386 and Alpha versions.
*/
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/ptrace.h>
#include <linux/tracehook.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/smp.h>
#include <linux/stddef.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/unistd.h>
#include <linux/wait.h>
#include <asm/intrinsics.h>
#include <asm/uaccess.h>
#include <asm/rse.h>
#include <asm/sigcontext.h>
#include "sigframe.h"
#define DEBUG_SIG 0
#define STACK_ALIGN 16 /* minimal alignment for stack pointer */
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
#if _NSIG_WORDS > 1
# define PUT_SIGSET(k,u) __copy_to_user((u)->sig, (k)->sig, sizeof(sigset_t))
# define GET_SIGSET(k,u) __copy_from_user((k)->sig, (u)->sig, sizeof(sigset_t))
#else
# define PUT_SIGSET(k,u) __put_user((k)->sig[0], &(u)->sig[0])
# define GET_SIGSET(k,u) __get_user((k)->sig[0], &(u)->sig[0])
#endif
asmlinkage long
sys_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, long arg2,
long arg3, long arg4, long arg5, long arg6, long arg7,
struct pt_regs regs)
{
return do_sigaltstack(uss, uoss, regs.r12);
}
static long
restore_sigcontext (struct sigcontext __user *sc, struct sigscratch *scr)
{
unsigned long ip, flags, nat, um, cfm, rsc;
long err;
/* Always make any pending restarted system calls return -EINTR */
current_thread_info()->restart_block.fn = do_no_restart_syscall;
/* restore scratch that always needs gets updated during signal delivery: */
err = __get_user(flags, &sc->sc_flags);
err |= __get_user(nat, &sc->sc_nat);
err |= __get_user(ip, &sc->sc_ip); /* instruction pointer */
err |= __get_user(cfm, &sc->sc_cfm);
err |= __get_user(um, &sc->sc_um); /* user mask */
err |= __get_user(rsc, &sc->sc_ar_rsc);
err |= __get_user(scr->pt.ar_unat, &sc->sc_ar_unat);
err |= __get_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr);
err |= __get_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
err |= __get_user(scr->pt.pr, &sc->sc_pr); /* predicates */
err |= __get_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */
err |= __get_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */
err |= __copy_from_user(&scr->pt.r1, &sc->sc_gr[1], 8); /* r1 */
err |= __copy_from_user(&scr->pt.r8, &sc->sc_gr[8], 4*8); /* r8-r11 */
err |= __copy_from_user(&scr->pt.r12, &sc->sc_gr[12], 2*8); /* r12-r13 */
err |= __copy_from_user(&scr->pt.r15, &sc->sc_gr[15], 8); /* r15 */
scr->pt.cr_ifs = cfm | (1UL << 63);
scr->pt.ar_rsc = rsc | (3 << 2); /* force PL3 */
/* establish new instruction pointer: */
scr->pt.cr_iip = ip & ~0x3UL;
ia64_psr(&scr->pt)->ri = ip & 0x3;
scr->pt.cr_ipsr = (scr->pt.cr_ipsr & ~IA64_PSR_UM) | (um & IA64_PSR_UM);
scr->scratch_unat = ia64_put_scratch_nat_bits(&scr->pt, nat);
if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
/* Restore most scratch-state only when not in syscall. */
err |= __get_user(scr->pt.ar_ccv, &sc->sc_ar_ccv); /* ar.ccv */
err |= __get_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */
err |= __get_user(scr->pt.r14, &sc->sc_gr[14]); /* r14 */
err |= __copy_from_user(&scr->pt.ar_csd, &sc->sc_ar25, 2*8); /* ar.csd & ar.ssd */
err |= __copy_from_user(&scr->pt.r2, &sc->sc_gr[2], 2*8); /* r2-r3 */
err |= __copy_from_user(&scr->pt.r16, &sc->sc_gr[16], 16*8); /* r16-r31 */
}
if ((flags & IA64_SC_FLAG_FPH_VALID) != 0) {
struct ia64_psr *psr = ia64_psr(&scr->pt);
err |= __copy_from_user(current->thread.fph, &sc->sc_fr[32], 96*16);
psr->mfh = 0; /* drop signal handler's fph contents... */
preempt_disable();
if (psr->dfh)
ia64_drop_fpu(current);
else {
/* We already own the local fph, otherwise psr->dfh wouldn't be 0. */
__ia64_load_fpu(current->thread.fph);
ia64_set_local_fpu_owner(current);
}
preempt_enable();
}
return err;
}
int
copy_siginfo_to_user (siginfo_t __user *to, siginfo_t *from)
{
if (!access_ok(VERIFY_WRITE, to, sizeof(siginfo_t)))
return -EFAULT;
if (from->si_code < 0) {
if (__copy_to_user(to, from, sizeof(siginfo_t)))
return -EFAULT;
return 0;
} else {
int err;
/*
* If you change siginfo_t structure, please be sure this code is fixed
* accordingly. It should never copy any pad contained in the structure
* to avoid security leaks, but must copy the generic 3 ints plus the
* relevant union member.
*/
err = __put_user(from->si_signo, &to->si_signo);
err |= __put_user(from->si_errno, &to->si_errno);
err |= __put_user((short)from->si_code, &to->si_code);
switch (from->si_code >> 16) {
case __SI_FAULT >> 16:
err |= __put_user(from->si_flags, &to->si_flags);
err |= __put_user(from->si_isr, &to->si_isr);
case __SI_POLL >> 16:
err |= __put_user(from->si_addr, &to->si_addr);
err |= __put_user(from->si_imm, &to->si_imm);
break;
case __SI_TIMER >> 16:
err |= __put_user(from->si_tid, &to->si_tid);
err |= __put_user(from->si_overrun, &to->si_overrun);
err |= __put_user(from->si_ptr, &to->si_ptr);
break;
case __SI_RT >> 16: /* Not generated by the kernel as of now. */
case __SI_MESGQ >> 16:
err |= __put_user(from->si_uid, &to->si_uid);
err |= __put_user(from->si_pid, &to->si_pid);
err |= __put_user(from->si_ptr, &to->si_ptr);
break;
case __SI_CHLD >> 16:
err |= __put_user(from->si_utime, &to->si_utime);
err |= __put_user(from->si_stime, &to->si_stime);
err |= __put_user(from->si_status, &to->si_status);
default:
err |= __put_user(from->si_uid, &to->si_uid);
err |= __put_user(from->si_pid, &to->si_pid);
break;
}
return err;
}
}
long
ia64_rt_sigreturn (struct sigscratch *scr)
{
extern char ia64_strace_leave_kernel, ia64_leave_kernel;
struct sigcontext __user *sc;
struct siginfo si;
sigset_t set;
long retval;
sc = &((struct sigframe __user *) (scr->pt.r12 + 16))->sc;
/*
* When we return to the previously executing context, r8 and r10 have already
* been setup the way we want them. Indeed, if the signal wasn't delivered while
* in a system call, we must not touch r8 or r10 as otherwise user-level state
* could be corrupted.
*/
retval = (long) &ia64_leave_kernel;
if (test_thread_flag(TIF_SYSCALL_TRACE)
|| test_thread_flag(TIF_SYSCALL_AUDIT))
/*
* strace expects to be notified after sigreturn returns even though the
* context to which we return may not be in the middle of a syscall.
* Thus, the return-value that strace displays for sigreturn is
* meaningless.
*/
retval = (long) &ia64_strace_leave_kernel;
if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
goto give_sigsegv;
if (GET_SIGSET(&set, &sc->sc_mask))
goto give_sigsegv;
sigdelsetmask(&set, ~_BLOCKABLE);
set_current_blocked(&set);
if (restore_sigcontext(sc, scr))
goto give_sigsegv;
#if DEBUG_SIG
printk("SIG return (%s:%d): sp=%lx ip=%lx\n",
current->comm, current->pid, scr->pt.r12, scr->pt.cr_iip);
#endif
/*
* It is more difficult to avoid calling this function than to
* call it and ignore errors.
*/
do_sigaltstack(&sc->sc_stack, NULL, scr->pt.r12);
return retval;
give_sigsegv:
si.si_signo = SIGSEGV;
si.si_errno = 0;
si.si_code = SI_KERNEL;
si.si_pid = task_pid_vnr(current);
si.si_uid = current_uid();
si.si_addr = sc;
force_sig_info(SIGSEGV, &si, current);
return retval;
}
/*
* This does just the minimum required setup of sigcontext.
* Specifically, it only installs data that is either not knowable at
* the user-level or that gets modified before execution in the
* trampoline starts. Everything else is done at the user-level.
*/
static long
setup_sigcontext (struct sigcontext __user *sc, sigset_t *mask, struct sigscratch *scr)
{
unsigned long flags = 0, ifs, cfm, nat;
long err = 0;
ifs = scr->pt.cr_ifs;
if (on_sig_stack((unsigned long) sc))
flags |= IA64_SC_FLAG_ONSTACK;
if ((ifs & (1UL << 63)) == 0)
/* if cr_ifs doesn't have the valid bit set, we got here through a syscall */
flags |= IA64_SC_FLAG_IN_SYSCALL;
cfm = ifs & ((1UL << 38) - 1);
ia64_flush_fph(current);
if ((current->thread.flags & IA64_THREAD_FPH_VALID)) {
flags |= IA64_SC_FLAG_FPH_VALID;
err = __copy_to_user(&sc->sc_fr[32], current->thread.fph, 96*16);
}
nat = ia64_get_scratch_nat_bits(&scr->pt, scr->scratch_unat);
err |= __put_user(flags, &sc->sc_flags);
err |= __put_user(nat, &sc->sc_nat);
err |= PUT_SIGSET(mask, &sc->sc_mask);
err |= __put_user(cfm, &sc->sc_cfm);
err |= __put_user(scr->pt.cr_ipsr & IA64_PSR_UM, &sc->sc_um);
err |= __put_user(scr->pt.ar_rsc, &sc->sc_ar_rsc);
err |= __put_user(scr->pt.ar_unat, &sc->sc_ar_unat); /* ar.unat */
err |= __put_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr); /* ar.fpsr */
err |= __put_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
err |= __put_user(scr->pt.pr, &sc->sc_pr); /* predicates */
err |= __put_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */
err |= __put_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */
err |= __copy_to_user(&sc->sc_gr[1], &scr->pt.r1, 8); /* r1 */
err |= __copy_to_user(&sc->sc_gr[8], &scr->pt.r8, 4*8); /* r8-r11 */
err |= __copy_to_user(&sc->sc_gr[12], &scr->pt.r12, 2*8); /* r12-r13 */
err |= __copy_to_user(&sc->sc_gr[15], &scr->pt.r15, 8); /* r15 */
err |= __put_user(scr->pt.cr_iip + ia64_psr(&scr->pt)->ri, &sc->sc_ip);
if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
/* Copy scratch regs to sigcontext if the signal didn't interrupt a syscall. */
err |= __put_user(scr->pt.ar_ccv, &sc->sc_ar_ccv); /* ar.ccv */
err |= __put_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */
err |= __put_user(scr->pt.r14, &sc->sc_gr[14]); /* r14 */
err |= __copy_to_user(&sc->sc_ar25, &scr->pt.ar_csd, 2*8); /* ar.csd & ar.ssd */
err |= __copy_to_user(&sc->sc_gr[2], &scr->pt.r2, 2*8); /* r2-r3 */
err |= __copy_to_user(&sc->sc_gr[16], &scr->pt.r16, 16*8); /* r16-r31 */
}
return err;
}
/*
* Check whether the register-backing store is already on the signal stack.
*/
static inline int
rbs_on_sig_stack (unsigned long bsp)
{
return (bsp - current->sas_ss_sp < current->sas_ss_size);
}
static long
force_sigsegv_info (int sig, void __user *addr)
{
unsigned long flags;
struct siginfo si;
if (sig == SIGSEGV) {
/*
* Acquiring siglock around the sa_handler-update is almost
* certainly overkill, but this isn't a
* performance-critical path and I'd rather play it safe
* here than having to debug a nasty race if and when
* something changes in kernel/signal.c that would make it
* no longer safe to modify sa_handler without holding the
* lock.
*/
spin_lock_irqsave(&current->sighand->siglock, flags);
current->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
spin_unlock_irqrestore(&current->sighand->siglock, flags);
}
si.si_signo = SIGSEGV;
si.si_errno = 0;
si.si_code = SI_KERNEL;
si.si_pid = task_pid_vnr(current);
si.si_uid = current_uid();
si.si_addr = addr;
force_sig_info(SIGSEGV, &si, current);
return 0;
}
static long
setup_frame (int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set,
struct sigscratch *scr)
{
extern char __kernel_sigtramp[];
unsigned long tramp_addr, new_rbs = 0, new_sp;
struct sigframe __user *frame;
long err;
new_sp = scr->pt.r12;
tramp_addr = (unsigned long) __kernel_sigtramp;
if (ka->sa.sa_flags & SA_ONSTACK) {
int onstack = sas_ss_flags(new_sp);
if (onstack == 0) {
new_sp = current->sas_ss_sp + current->sas_ss_size;
/*
* We need to check for the register stack being on the
* signal stack separately, because it's switched
* separately (memory stack is switched in the kernel,
* register stack is switched in the signal trampoline).
*/
if (!rbs_on_sig_stack(scr->pt.ar_bspstore))
new_rbs = ALIGN(current->sas_ss_sp,
sizeof(long));
} else if (onstack == SS_ONSTACK) {
unsigned long check_sp;
/*
* If we are on the alternate signal stack and would
* overflow it, don't. Return an always-bogus address
* instead so we will die with SIGSEGV.
*/
check_sp = (new_sp - sizeof(*frame)) & -STACK_ALIGN;
if (!likely(on_sig_stack(check_sp)))
return force_sigsegv_info(sig, (void __user *)
check_sp);
}
}
frame = (void __user *) ((new_sp - sizeof(*frame)) & -STACK_ALIGN);
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
return force_sigsegv_info(sig, frame);
err = __put_user(sig, &frame->arg0);
err |= __put_user(&frame->info, &frame->arg1);
err |= __put_user(&frame->sc, &frame->arg2);
err |= __put_user(new_rbs, &frame->sc.sc_rbs_base);
err |= __put_user(0, &frame->sc.sc_loadrs); /* initialize to zero */
err |= __put_user(ka->sa.sa_handler, &frame->handler);
err |= copy_siginfo_to_user(&frame->info, info);
err |= __put_user(current->sas_ss_sp, &frame->sc.sc_stack.ss_sp);
err |= __put_user(current->sas_ss_size, &frame->sc.sc_stack.ss_size);
err |= __put_user(sas_ss_flags(scr->pt.r12), &frame->sc.sc_stack.ss_flags);
err |= setup_sigcontext(&frame->sc, set, scr);
if (unlikely(err))
return force_sigsegv_info(sig, frame);
scr->pt.r12 = (unsigned long) frame - 16; /* new stack pointer */
scr->pt.ar_fpsr = FPSR_DEFAULT; /* reset fpsr for signal handler */
scr->pt.cr_iip = tramp_addr;
ia64_psr(&scr->pt)->ri = 0; /* start executing in first slot */
ia64_psr(&scr->pt)->be = 0; /* force little-endian byte-order */
/*
* Force the interruption function mask to zero. This has no effect when a
* system-call got interrupted by a signal (since, in that case, scr->pt_cr_ifs is
* ignored), but it has the desirable effect of making it possible to deliver a
* signal with an incomplete register frame (which happens when a mandatory RSE
* load faults). Furthermore, it has no negative effect on the getting the user's
* dirty partition preserved, because that's governed by scr->pt.loadrs.
*/
scr->pt.cr_ifs = (1UL << 63);
/*
* Note: this affects only the NaT bits of the scratch regs (the ones saved in
* pt_regs), which is exactly what we want.
*/
scr->scratch_unat = 0; /* ensure NaT bits of r12 is clear */
#if DEBUG_SIG
printk("SIG deliver (%s:%d): sig=%d sp=%lx ip=%lx handler=%p\n",
current->comm, current->pid, sig, scr->pt.r12, frame->sc.sc_ip, frame->handler);
#endif
return 1;
}
static long
handle_signal (unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset,
struct sigscratch *scr)
{
if (!setup_frame(sig, ka, info, oldset, scr))
return 0;
block_sigmask(ka, sig);
/*
* Let tracing know that we've done the handler setup.
*/
tracehook_signal_handler(sig, info, ka, &scr->pt,
test_thread_flag(TIF_SINGLESTEP));
return 1;
}
/*
* 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.
*/
void
ia64_do_signal (struct sigscratch *scr, long in_syscall)
{
struct k_sigaction ka;
sigset_t *oldset;
siginfo_t info;
long restart = in_syscall;
long errno = scr->pt.r8;
/*
* In the ia64_leave_kernel code path, 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(&scr->pt))
return;
if (current_thread_info()->status & TS_RESTORE_SIGMASK)
oldset = &current->saved_sigmask;
else
oldset = &current->blocked;
/*
* This only loops in the rare cases of handle_signal() failing, in which case we
* need to push through a forced SIGSEGV.
*/
while (1) {
int signr = get_signal_to_deliver(&info, &ka, &scr->pt, NULL);
/*
* get_signal_to_deliver() may have run a debugger (via notify_parent())
* and the debugger may have modified the state (e.g., to arrange for an
* inferior call), thus it's important to check for restarting _after_
* get_signal_to_deliver().
*/
if ((long) scr->pt.r10 != -1)
/*
* A system calls has to be restarted only if one of the error codes
* ERESTARTNOHAND, ERESTARTSYS, or ERESTARTNOINTR is returned. If r10
* isn't -1 then r8 doesn't hold an error code and we don't need to
* restart the syscall, so we can clear the "restart" flag here.
*/
restart = 0;
if (signr <= 0)
break;
if (unlikely(restart)) {
switch (errno) {
case ERESTART_RESTARTBLOCK:
case ERESTARTNOHAND:
scr->pt.r8 = EINTR;
/* note: scr->pt.r10 is already -1 */
break;
case ERESTARTSYS:
if ((ka.sa.sa_flags & SA_RESTART) == 0) {
scr->pt.r8 = EINTR;
/* note: scr->pt.r10 is already -1 */
break;
}
case ERESTARTNOINTR:
ia64_decrement_ip(&scr->pt);
restart = 0; /* don't restart twice if handle_signal() fails... */
}
}
/*
* Whee! Actually deliver the signal. If the delivery failed, we need to
* continue to iterate in this loop so we can deliver the SIGSEGV...
*/
if (handle_signal(signr, &ka, &info, oldset, scr)) {
/*
* A signal was successfully delivered; the saved
* sigmask will have been stored in the signal frame,
* and will be restored by sigreturn, so we can simply
* clear the TS_RESTORE_SIGMASK flag.
*/
current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
return;
}
}
/* Did we come from a system call? */
if (restart) {
/* Restart the system call - no handlers present */
if (errno == ERESTARTNOHAND || errno == ERESTARTSYS || errno == ERESTARTNOINTR
|| errno == ERESTART_RESTARTBLOCK)
{
/*
* Note: the syscall number is in r15 which is saved in
* pt_regs so all we need to do here is adjust ip so that
* the "break" instruction gets re-executed.
*/
ia64_decrement_ip(&scr->pt);
if (errno == ERESTART_RESTARTBLOCK)
scr->pt.r15 = __NR_restart_syscall;
}
}
/* if there's no signal to deliver, we just put the saved sigmask
* back */
if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
}
}