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ee18d64c1f
linux/arch/mips/kernel/signal.c
David Howells ee18d64c1f KEYS: Add a keyctl to install a process's session keyring on its parent [try #6] 
Add a keyctl to install a process's session keyring onto its parent.  This
replaces the parent's session keyring.  Because the COW credential code does
not permit one process to change another process's credentials directly, the
change is deferred until userspace next starts executing again.  Normally this
will be after a wait*() syscall.

To support this, three new security hooks have been provided:
cred_alloc_blank() to allocate unset security creds, cred_transfer() to fill in
the blank security creds and key_session_to_parent() - which asks the LSM if
the process may replace its parent's session keyring.

The replacement may only happen if the process has the same ownership details
as its parent, and the process has LINK permission on the session keyring, and
the session keyring is owned by the process, and the LSM permits it.

Note that this requires alteration to each architecture's notify_resume path.
This has been done for all arches barring blackfin, m68k* and xtensa, all of
which need assembly alteration to support TIF_NOTIFY_RESUME.  This allows the
replacement to be performed at the point the parent process resumes userspace
execution.

This allows the userspace AFS pioctl emulation to fully emulate newpag() and
the VIOCSETTOK and VIOCSETTOK2 pioctls, all of which require the ability to
alter the parent process's PAG membership.  However, since kAFS doesn't use
PAGs per se, but rather dumps the keys into the session keyring, the session
keyring of the parent must be replaced if, for example, VIOCSETTOK is passed
the newpag flag.

This can be tested with the following program:

	#include <stdio.h>
	#include <stdlib.h>
	#include <keyutils.h>

	#define KEYCTL_SESSION_TO_PARENT	18

	#define OSERROR(X, S) do { if ((long)(X) == -1) { perror(S); exit(1); } } while(0)

	int main(int argc, char **argv)
	{
		key_serial_t keyring, key;
		long ret;

		keyring = keyctl_join_session_keyring(argv[1]);
		OSERROR(keyring, "keyctl_join_session_keyring");

		key = add_key("user", "a", "b", 1, keyring);
		OSERROR(key, "add_key");

		ret = keyctl(KEYCTL_SESSION_TO_PARENT);
		OSERROR(ret, "KEYCTL_SESSION_TO_PARENT");

		return 0;
	}

Compiled and linked with -lkeyutils, you should see something like:

	[dhowells@andromeda ~]$ keyctl show
	Session Keyring
	       -3 --alswrv   4043  4043  keyring: _ses
	355907932 --alswrv   4043    -1   \_ keyring: _uid.4043
	[dhowells@andromeda ~]$ /tmp/newpag
	[dhowells@andromeda ~]$ keyctl show
	Session Keyring
	       -3 --alswrv   4043  4043  keyring: _ses
	1055658746 --alswrv   4043  4043   \_ user: a
	[dhowells@andromeda ~]$ /tmp/newpag hello
	[dhowells@andromeda ~]$ keyctl show
	Session Keyring
	       -3 --alswrv   4043  4043  keyring: hello
	340417692 --alswrv   4043  4043   \_ user: a

Where the test program creates a new session keyring, sticks a user key named
'a' into it and then installs it on its parent.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-09-02 21:29:22 +10:00

711 lines
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/*
* 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.
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 1994 - 2000 Ralf Baechle
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
*/
#include <linux/cache.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/personality.h>
#include <linux/smp.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/compiler.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <asm/abi.h>
#include <asm/asm.h>
#include <linux/bitops.h>
#include <asm/cacheflush.h>
#include <asm/fpu.h>
#include <asm/sim.h>
#include <asm/ucontext.h>
#include <asm/cpu-features.h>
#include <asm/war.h>
#include "signal-common.h"
/*
* Horribly complicated - with the bloody RM9000 workarounds enabled
* the signal trampolines is moving to the end of the structure so we can
* increase the alignment without breaking software compatibility.
*/
#if ICACHE_REFILLS_WORKAROUND_WAR == 0
struct sigframe {
u32 sf_ass[4]; /* argument save space for o32 */
u32 sf_code[2]; /* signal trampoline */
struct sigcontext sf_sc;
sigset_t sf_mask;
};
struct rt_sigframe {
u32 rs_ass[4]; /* argument save space for o32 */
u32 rs_code[2]; /* signal trampoline */
struct siginfo rs_info;
struct ucontext rs_uc;
};
#else
struct sigframe {
u32 sf_ass[4]; /* argument save space for o32 */
u32 sf_pad[2];
struct sigcontext sf_sc; /* hw context */
sigset_t sf_mask;
u32 sf_code[8] ____cacheline_aligned; /* signal trampoline */
};
struct rt_sigframe {
u32 rs_ass[4]; /* argument save space for o32 */
u32 rs_pad[2];
struct siginfo rs_info;
struct ucontext rs_uc;
u32 rs_code[8] ____cacheline_aligned; /* signal trampoline */
};
#endif
/*
* Helper routines
*/
static int protected_save_fp_context(struct sigcontext __user *sc)
{
int err;
while (1) {
lock_fpu_owner();
own_fpu_inatomic(1);
err = save_fp_context(sc); /* this might fail */
unlock_fpu_owner();
if (likely(!err))
break;
/* touch the sigcontext and try again */
err = __put_user(0, &sc->sc_fpregs[0]) |
__put_user(0, &sc->sc_fpregs[31]) |
__put_user(0, &sc->sc_fpc_csr);
if (err)
break; /* really bad sigcontext */
}
return err;
}
static int protected_restore_fp_context(struct sigcontext __user *sc)
{
int err, tmp;
while (1) {
lock_fpu_owner();
own_fpu_inatomic(0);
err = restore_fp_context(sc); /* this might fail */
unlock_fpu_owner();
if (likely(!err))
break;
/* touch the sigcontext and try again */
err = __get_user(tmp, &sc->sc_fpregs[0]) |
__get_user(tmp, &sc->sc_fpregs[31]) |
__get_user(tmp, &sc->sc_fpc_csr);
if (err)
break; /* really bad sigcontext */
}
return err;
}
int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
{
int err = 0;
int i;
unsigned int used_math;
err |= __put_user(regs->cp0_epc, &sc->sc_pc);
err |= __put_user(0, &sc->sc_regs[0]);
for (i = 1; i < 32; i++)
err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
#ifdef CONFIG_CPU_HAS_SMARTMIPS
err |= __put_user(regs->acx, &sc->sc_acx);
#endif
err |= __put_user(regs->hi, &sc->sc_mdhi);
err |= __put_user(regs->lo, &sc->sc_mdlo);
if (cpu_has_dsp) {
err |= __put_user(mfhi1(), &sc->sc_hi1);
err |= __put_user(mflo1(), &sc->sc_lo1);
err |= __put_user(mfhi2(), &sc->sc_hi2);
err |= __put_user(mflo2(), &sc->sc_lo2);
err |= __put_user(mfhi3(), &sc->sc_hi3);
err |= __put_user(mflo3(), &sc->sc_lo3);
err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
}
used_math = !!used_math();
err |= __put_user(used_math, &sc->sc_used_math);
if (used_math) {
/*
* Save FPU state to signal context. Signal handler
* will "inherit" current FPU state.
*/
err |= protected_save_fp_context(sc);
}
return err;
}
int fpcsr_pending(unsigned int __user *fpcsr)
{
int err, sig = 0;
unsigned int csr, enabled;
err = __get_user(csr, fpcsr);
enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
/*
* If the signal handler set some FPU exceptions, clear it and
* send SIGFPE.
*/
if (csr & enabled) {
csr &= ~enabled;
err |= __put_user(csr, fpcsr);
sig = SIGFPE;
}
return err ?: sig;
}
static int
check_and_restore_fp_context(struct sigcontext __user *sc)
{
int err, sig;
err = sig = fpcsr_pending(&sc->sc_fpc_csr);
if (err > 0)
err = 0;
err |= protected_restore_fp_context(sc);
return err ?: sig;
}
int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
{
unsigned int used_math;
unsigned long treg;
int err = 0;
int i;
/* Always make any pending restarted system calls return -EINTR */
current_thread_info()->restart_block.fn = do_no_restart_syscall;
err |= __get_user(regs->cp0_epc, &sc->sc_pc);
#ifdef CONFIG_CPU_HAS_SMARTMIPS
err |= __get_user(regs->acx, &sc->sc_acx);
#endif
err |= __get_user(regs->hi, &sc->sc_mdhi);
err |= __get_user(regs->lo, &sc->sc_mdlo);
if (cpu_has_dsp) {
err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
}
for (i = 1; i < 32; i++)
err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
err |= __get_user(used_math, &sc->sc_used_math);
conditional_used_math(used_math);
if (used_math) {
/* restore fpu context if we have used it before */
if (!err)
err = check_and_restore_fp_context(sc);
} else {
/* signal handler may have used FPU. Give it up. */
lose_fpu(0);
}
return err;
}
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->regs[29];
/*
* FPU emulator may have it's own trampoline active just
* above the user stack, 16-bytes before the next lowest
* 16 byte boundary. Try to avoid trashing it.
*/
sp -= 32;
/* This is the X/Open sanctioned signal stack switching. */
if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags (sp) == 0))
sp = current->sas_ss_sp + current->sas_ss_size;
return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK));
}
int install_sigtramp(unsigned int __user *tramp, unsigned int syscall)
{
int err;
/*
* Set up the return code ...
*
* li v0, __NR__foo_sigreturn
* syscall
*/
err = __put_user(0x24020000 + syscall, tramp + 0);
err |= __put_user(0x0000000c , tramp + 1);
if (ICACHE_REFILLS_WORKAROUND_WAR) {
err |= __put_user(0, tramp + 2);
err |= __put_user(0, tramp + 3);
err |= __put_user(0, tramp + 4);
err |= __put_user(0, tramp + 5);
err |= __put_user(0, tramp + 6);
err |= __put_user(0, tramp + 7);
}
flush_cache_sigtramp((unsigned long) tramp);
return err;
}
/*
* Atomically swap in the new signal mask, and wait for a signal.
*/
#ifdef CONFIG_TRAD_SIGNALS
asmlinkage int sys_sigsuspend(nabi_no_regargs struct pt_regs regs)
{
sigset_t newset;
sigset_t __user *uset;
uset = (sigset_t __user *) regs.regs[4];
if (copy_from_user(&newset, uset, sizeof(sigset_t)))
return -EFAULT;
sigdelsetmask(&newset, ~_BLOCKABLE);
spin_lock_irq(&current->sighand->siglock);
current->saved_sigmask = current->blocked;
current->blocked = newset;
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
current->state = TASK_INTERRUPTIBLE;
schedule();
set_thread_flag(TIF_RESTORE_SIGMASK);
return -ERESTARTNOHAND;
}
#endif
asmlinkage int sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
{
sigset_t newset;
sigset_t __user *unewset;
size_t sigsetsize;
/* XXX Don't preclude handling different sized sigset_t's. */
sigsetsize = regs.regs[5];
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
unewset = (sigset_t __user *) regs.regs[4];
if (copy_from_user(&newset, unewset, sizeof(newset)))
return -EFAULT;
sigdelsetmask(&newset, ~_BLOCKABLE);
spin_lock_irq(&current->sighand->siglock);
current->saved_sigmask = current->blocked;
current->blocked = newset;
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
current->state = TASK_INTERRUPTIBLE;
schedule();
set_thread_flag(TIF_RESTORE_SIGMASK);
return -ERESTARTNOHAND;
}
#ifdef CONFIG_TRAD_SIGNALS
SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
struct sigaction __user *, oact)
{
struct k_sigaction new_ka, old_ka;
int ret;
int err = 0;
if (act) {
old_sigset_t mask;
if (!access_ok(VERIFY_READ, act, sizeof(*act)))
return -EFAULT;
err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
err |= __get_user(mask, &act->sa_mask.sig[0]);
if (err)
return -EFAULT;
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)))
return -EFAULT;
err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
err |= __put_user(0, &oact->sa_mask.sig[1]);
err |= __put_user(0, &oact->sa_mask.sig[2]);
err |= __put_user(0, &oact->sa_mask.sig[3]);
if (err)
return -EFAULT;
}
return ret;
}
#endif
asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
{
const stack_t __user *uss = (const stack_t __user *) regs.regs[4];
stack_t __user *uoss = (stack_t __user *) regs.regs[5];
unsigned long usp = regs.regs[29];
return do_sigaltstack(uss, uoss, usp);
}
#ifdef CONFIG_TRAD_SIGNALS
asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
{
struct sigframe __user *frame;
sigset_t blocked;
int sig;
frame = (struct sigframe __user *) regs.regs[29];
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
goto badframe;
sigdelsetmask(&blocked, ~_BLOCKABLE);
spin_lock_irq(&current->sighand->siglock);
current->blocked = blocked;
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
sig = restore_sigcontext(&regs, &frame->sf_sc);
if (sig < 0)
goto badframe;
else if (sig)
force_sig(sig, current);
/*
* Don't let your children do this ...
*/
__asm__ __volatile__(
"move\t$29, %0\n\t"
"j\tsyscall_exit"
:/* no outputs */
:"r" (&regs));
/* Unreached */
badframe:
force_sig(SIGSEGV, current);
}
#endif /* CONFIG_TRAD_SIGNALS */
asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
{
struct rt_sigframe __user *frame;
sigset_t set;
stack_t st;
int sig;
frame = (struct rt_sigframe __user *) regs.regs[29];
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&set, &frame->rs_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);
sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
if (sig < 0)
goto badframe;
else if (sig)
force_sig(sig, current);
if (__copy_from_user(&st, &frame->rs_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((stack_t __user *)&st, NULL, regs.regs[29]);
/*
* Don't let your children do this ...
*/
__asm__ __volatile__(
"move\t$29, %0\n\t"
"j\tsyscall_exit"
:/* no outputs */
:"r" (&regs));
/* Unreached */
badframe:
force_sig(SIGSEGV, current);
}
#ifdef CONFIG_TRAD_SIGNALS
static int setup_frame(struct k_sigaction * ka, struct pt_regs *regs,
int signr, sigset_t *set)
{
struct sigframe __user *frame;
int err = 0;
frame = get_sigframe(ka, regs, sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
goto give_sigsegv;
err |= install_sigtramp(frame->sf_code, __NR_sigreturn);
err |= setup_sigcontext(regs, &frame->sf_sc);
err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
if (err)
goto give_sigsegv;
/*
* Arguments to signal handler:
*
* a0 = signal number
* a1 = 0 (should be cause)
* a2 = pointer to struct sigcontext
*
* $25 and c0_epc point to the signal handler, $29 points to the
* struct sigframe.
*/
regs->regs[ 4] = signr;
regs->regs[ 5] = 0;
regs->regs[ 6] = (unsigned long) &frame->sf_sc;
regs->regs[29] = (unsigned long) frame;
regs->regs[31] = (unsigned long) frame->sf_code;
regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
current->comm, current->pid,
frame, regs->cp0_epc, regs->regs[31]);
return 0;
give_sigsegv:
force_sigsegv(signr, current);
return -EFAULT;
}
#endif
static int setup_rt_frame(struct k_sigaction * ka, struct pt_regs *regs,
int signr, sigset_t *set, siginfo_t *info)
{
struct rt_sigframe __user *frame;
int err = 0;
frame = get_sigframe(ka, regs, sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
goto give_sigsegv;
err |= install_sigtramp(frame->rs_code, __NR_rt_sigreturn);
/* Create siginfo. */
err |= copy_siginfo_to_user(&frame->rs_info, info);
/* Create the ucontext. */
err |= __put_user(0, &frame->rs_uc.uc_flags);
err |= __put_user(NULL, &frame->rs_uc.uc_link);
err |= __put_user((void __user *)current->sas_ss_sp,
&frame->rs_uc.uc_stack.ss_sp);
err |= __put_user(sas_ss_flags(regs->regs[29]),
&frame->rs_uc.uc_stack.ss_flags);
err |= __put_user(current->sas_ss_size,
&frame->rs_uc.uc_stack.ss_size);
err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
if (err)
goto give_sigsegv;
/*
* Arguments to signal handler:
*
* a0 = signal number
* a1 = 0 (should be cause)
* a2 = pointer to ucontext
*
* $25 and c0_epc point to the signal handler, $29 points to
* the struct rt_sigframe.
*/
regs->regs[ 4] = signr;
regs->regs[ 5] = (unsigned long) &frame->rs_info;
regs->regs[ 6] = (unsigned long) &frame->rs_uc;
regs->regs[29] = (unsigned long) frame;
regs->regs[31] = (unsigned long) frame->rs_code;
regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
current->comm, current->pid,
frame, regs->cp0_epc, regs->regs[31]);
return 0;
give_sigsegv:
force_sigsegv(signr, current);
return -EFAULT;
}
struct mips_abi mips_abi = {
#ifdef CONFIG_TRAD_SIGNALS
.setup_frame = setup_frame,
#endif
.setup_rt_frame = setup_rt_frame,
.restart = __NR_restart_syscall
};
static int handle_signal(unsigned long sig, siginfo_t *info,
struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
{
int ret;
switch(regs->regs[0]) {
case ERESTART_RESTARTBLOCK:
case ERESTARTNOHAND:
regs->regs[2] = EINTR;
break;
case ERESTARTSYS:
if (!(ka->sa.sa_flags & SA_RESTART)) {
regs->regs[2] = EINTR;
break;
}
/* fallthrough */
case ERESTARTNOINTR: /* Userland will reload $v0. */
regs->regs[7] = regs->regs[26];
regs->cp0_epc -= 8;
}
regs->regs[0] = 0; /* Don't deal with this again. */
if (sig_uses_siginfo(ka))
ret = current->thread.abi->setup_rt_frame(ka, regs, sig, oldset, info);
else
ret = current->thread.abi->setup_frame(ka, regs, sig, oldset);
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;
}
static void do_signal(struct pt_regs *regs)
{
struct k_sigaction ka;
sigset_t *oldset;
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;
if (test_thread_flag(TIF_RESTORE_SIGMASK))
oldset = &current->saved_sigmask;
else
oldset = &current->blocked;
signr = get_signal_to_deliver(&info, &ka, regs, NULL);
if (signr > 0) {
/* Whee! Actually deliver the signal. */
if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
/*
* 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 TIF_RESTORE_SIGMASK flag.
*/
if (test_thread_flag(TIF_RESTORE_SIGMASK))
clear_thread_flag(TIF_RESTORE_SIGMASK);
}
return;
}
/*
* Who's code doesn't conform to the restartable syscall convention
* dies here!!! The li instruction, a single machine instruction,
* must directly be followed by the syscall instruction.
*/
if (regs->regs[0]) {
if (regs->regs[2] == ERESTARTNOHAND ||
regs->regs[2] == ERESTARTSYS ||
regs->regs[2] == ERESTARTNOINTR) {
regs->regs[7] = regs->regs[26];
regs->cp0_epc -= 8;
}
if (regs->regs[2] == ERESTART_RESTARTBLOCK) {
regs->regs[2] = current->thread.abi->restart;
regs->regs[7] = regs->regs[26];
regs->cp0_epc -= 4;
}
regs->regs[0] = 0; /* Don't deal with this again. */
}
/*
* If there's no signal to deliver, we just put the saved sigmask
* back
*/
if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
clear_thread_flag(TIF_RESTORE_SIGMASK);
sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
}
}
/*
* notification of userspace execution resumption
* - triggered by the TIF_WORK_MASK flags
*/
asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
__u32 thread_info_flags)
{
/* deal with pending signal delivery */
if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
do_signal(regs);
if (thread_info_flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
if (current->replacement_session_keyring)
key_replace_session_keyring();
}
}
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