Commit 4e21fc13 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 

Pull third pile of kernel_execve() patches from Al Viro:
 "The last bits of infrastructure for kernel_thread() et.al., with
  alpha/arm/x86 use of those.  Plus sanitizing the asm glue and
  do_notify_resume() on alpha, fixing the "disabled irq while running
  task_work stuff" breakage there.

  At that point the rest of kernel_thread/kernel_execve/sys_execve work
  can be done independently for different architectures.  The only
  pending bits that do depend on having all architectures converted are
  restrictred to fs/* and kernel/* - that'll obviously have to wait for
  the next cycle.

  I thought we'd have to wait for all of them done before we start
  eliminating the longjump-style insanity in kernel_execve(), but it
  turned out there's a very simple way to do that without flagday-style
  changes."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
  alpha: switch to saner kernel_execve() semantics
  arm: switch to saner kernel_execve() semantics
  x86, um: convert to saner kernel_execve() semantics
  infrastructure for saner ret_from_kernel_thread semantics
  make sure that kernel_thread() callbacks call do_exit() themselves
  make sure that we always have a return path from kernel_execve()
  ppc: eeh_event should just use kthread_run()
  don't bother with kernel_thread/kernel_execve for launching linuxrc
  alpha: get rid of switch_stack argument of do_work_pending()
  alpha: don't bother passing switch_stack separately from regs
  alpha: take SIGPENDING/NOTIFY_RESUME loop into signal.c
  alpha: simplify TIF_NEED_RESCHED handling
parents 8418263e 5522be6a

arch/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -274,6 +274,9 @@ config ARCH_WANT_OLD_COMPAT_IPC 
config GENERIC_KERNEL_THREAD

	bool



config GENERIC_KERNEL_EXECVE

	bool



config HAVE_ARCH_SECCOMP_FILTER

	bool

	help

arch/alpha/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ config ALPHA 
	select GENERIC_STRNCPY_FROM_USER

	select GENERIC_STRNLEN_USER

	select GENERIC_KERNEL_THREAD

	select GENERIC_KERNEL_EXECVE

	help

	  The Alpha is a 64-bit general-purpose processor designed and

	  marketed by the Digital Equipment Corporation of blessed memory,

arch/alpha/include/asm/unistd.h

+0 −1
Original line number Diff line number Diff line
@@ -482,7 +482,6 @@ 
#define __ARCH_WANT_SYS_SIGPENDING

#define __ARCH_WANT_SYS_RT_SIGSUSPEND

#define __ARCH_WANT_SYS_EXECVE

#define __ARCH_WANT_KERNEL_EXECVE



/* "Conditional" syscalls.  What we want is

arch/alpha/kernel/entry.S

+28 −59
Original line number Diff line number Diff line
@@ -311,7 +311,7 @@ entSys: 


	.align	4

ret_from_sys_call:

	cmovne	$26, 0, $19		/* $19 = 0 => non-restartable */

	cmovne	$26, 0, $18		/* $18 = 0 => non-restartable */

	ldq	$0, SP_OFF($sp)

	and	$0, 8, $0

	beq	$0, ret_to_kernel
@@ -320,8 +320,8 @@ ret_to_user: 
		sampling and the rti.  */

	lda	$16, 7

	call_pal PAL_swpipl

	ldl	$5, TI_FLAGS($8)

	and	$5, _TIF_WORK_MASK, $2

	ldl	$17, TI_FLAGS($8)

	and	$17, _TIF_WORK_MASK, $2

	bne	$2, work_pending

restore_all:

	RESTORE_ALL
@@ -341,10 +341,10 @@ $syscall_error: 
	 * frame to indicate that a negative return value wasn't an

	 * error number..

	 */

	ldq	$19, 0($sp)	/* old syscall nr (zero if success) */

	beq	$19, $ret_success

	ldq	$18, 0($sp)	/* old syscall nr (zero if success) */

	beq	$18, $ret_success



	ldq	$20, 72($sp)	/* .. and this a3 */

	ldq	$19, 72($sp)	/* .. and this a3 */

	subq	$31, $0, $0	/* with error in v0 */

	addq	$31, 1, $1	/* set a3 for errno return */

	stq	$0, 0($sp)
@@ -362,51 +362,35 @@ $ret_success: 
 * Do all cleanup when returning from all interrupts and system calls.

 *

 * Arguments:

 *       $5: TI_FLAGS.

 *       $8: current.

 *      $19: The old syscall number, or zero if this is not a return

 *      $17: TI_FLAGS.

 *      $18: The old syscall number, or zero if this is not a return

 *           from a syscall that errored and is possibly restartable.

 *      $20: The old a3 value

 *      $19: The old a3 value

 */



	.align	4

	.ent	work_pending

work_pending:

	and	$5, _TIF_NEED_RESCHED, $2

	beq	$2, $work_notifysig

	and	$17, _TIF_NOTIFY_RESUME | _TIF_SIGPENDING, $2

	bne	$2, $work_notifysig



$work_resched:

	subq	$sp, 16, $sp

	stq	$19, 0($sp)              /* save syscall nr */

	stq	$20, 8($sp)              /* and error indication (a3) */

	/*

	 * We can get here only if we returned from syscall without SIGPENDING

	 * or got through work_notifysig already.  Either case means no syscall

	 * restarts for us, so let $18 and $19 burn.

	 */

	jsr	$26, schedule

	ldq	$19, 0($sp)

	ldq	$20, 8($sp)

	addq	$sp, 16, $sp

	/* Make sure need_resched and sigpending don't change between

		sampling and the rti.  */

	lda	$16, 7

	call_pal PAL_swpipl

	ldl	$5, TI_FLAGS($8)

	and	$5, _TIF_WORK_MASK, $2

	beq	$2, restore_all

	and	$5, _TIF_NEED_RESCHED, $2

	bne	$2, $work_resched

	mov	0, $18

	br	ret_to_user



$work_notifysig:

	mov	$sp, $16

	bsr	$1, do_switch_stack

	mov	$sp, $17

	mov	$5, $18

	mov	$19, $9		/* save old syscall number */

	mov	$20, $10	/* save old a3 */

	and	$5, _TIF_SIGPENDING, $2

	cmovne	$2, 0, $9	/* we don't want double syscall restarts */

	jsr	$26, do_notify_resume

	mov	$9, $19

	mov	$10, $20

	jsr	$26, do_work_pending

	bsr	$1, undo_switch_stack

	br	ret_to_user

	br	restore_all

.end work_pending



/*
@@ -454,9 +438,9 @@ $strace_success: 


	.align	3

$strace_error:

	ldq	$19, 0($sp)	/* old syscall nr (zero if success) */

	beq	$19, $strace_success

	ldq	$20, 72($sp)	/* .. and this a3 */

	ldq	$18, 0($sp)	/* old syscall nr (zero if success) */

	beq	$18, $strace_success

	ldq	$19, 72($sp)	/* .. and this a3 */



	subq	$31, $0, $0	/* with error in v0 */

	addq	$31, 1, $1	/* set a3 for errno return */
@@ -464,11 +448,11 @@ $strace_error: 
	stq	$1, 72($sp)	/* a3 for return */



	bsr	$1, do_switch_stack

	mov	$19, $9		/* save old syscall number */

	mov	$20, $10	/* save old a3 */

	mov	$18, $9		/* save old syscall number */

	mov	$19, $10	/* save old a3 */

	jsr	$26, syscall_trace_leave

	mov	$9, $19

	mov	$10, $20

	mov	$9, $18

	mov	$10, $19

	bsr	$1, undo_switch_stack



	mov	$31, $26	/* tell "ret_from_sys_call" we can restart */
@@ -619,24 +603,9 @@ ret_from_kernel_thread: 
	mov	$9, $27

	mov	$10, $16

	jsr	$26, ($9)

	ldgp	$gp, 0($26)

	mov	$0, $16

	mov	$31, $26

	jmp	$31, sys_exit

.end ret_from_kernel_thread



	.globl	ret_from_kernel_execve

	.align	4

	.ent	ret_from_kernel_execve

ret_from_kernel_execve:

	mov	$16, $sp

	/* Avoid the HAE being gratuitously wrong, to avoid restoring it.  */

	ldq	$2, alpha_mv+HAE_CACHE

	stq	$2, 152($sp)		/* HAE */

	mov	$31, $19		/* to disable syscall restarts */

	br	$31, ret_to_user



.end	ret_from_kernel_execve

.end ret_from_kernel_thread





/*

arch/alpha/kernel/signal.c

+28 −20
Original line number Diff line number Diff line
@@ -298,8 +298,9 @@ get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size) 


static long

setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, 

		 struct switch_stack *sw, unsigned long mask, unsigned long sp)

		 unsigned long mask, unsigned long sp)

{

	struct switch_stack *sw = (struct switch_stack *)regs - 1;

	long i, err = 0;



	err |= __put_user(on_sig_stack((unsigned long)sc), &sc->sc_onstack);
@@ -354,7 +355,7 @@ setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, 


static int

setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,

	    struct pt_regs *regs, struct switch_stack * sw)

	    struct pt_regs *regs)

{

	unsigned long oldsp, r26, err = 0;

	struct sigframe __user *frame;
@@ -364,7 +365,7 @@ setup_frame(int sig, struct k_sigaction *ka, sigset_t *set, 
	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))

		return -EFAULT;



	err |= setup_sigcontext(&frame->sc, regs, sw, set->sig[0], oldsp);

	err |= setup_sigcontext(&frame->sc, regs, set->sig[0], oldsp);

	if (err)

		return -EFAULT;
@@ -401,7 +402,7 @@ setup_frame(int sig, struct k_sigaction *ka, sigset_t *set, 


static int

setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,

	       sigset_t *set, struct pt_regs *regs, struct switch_stack * sw)

	       sigset_t *set, struct pt_regs *regs)

{

	unsigned long oldsp, r26, err = 0;

	struct rt_sigframe __user *frame;
@@ -420,7 +421,7 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, 
	err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);

	err |= __put_user(sas_ss_flags(oldsp), &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, sw,

	err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, 

				set->sig[0], oldsp);

	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	if (err)
@@ -464,15 +465,15 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, 
 */

static inline void

handle_signal(int sig, struct k_sigaction *ka, siginfo_t *info,

	      struct pt_regs * regs, struct switch_stack *sw)

	      struct pt_regs * regs)

{

	sigset_t *oldset = sigmask_to_save();

	int ret;



	if (ka->sa.sa_flags & SA_SIGINFO)

		ret = setup_rt_frame(sig, ka, info, oldset, regs, sw);

		ret = setup_rt_frame(sig, ka, info, oldset, regs);

	else

		ret = setup_frame(sig, ka, oldset, regs, sw);

		ret = setup_frame(sig, ka, oldset, regs);



	if (ret) {

		force_sigsegv(sig, current);
@@ -519,8 +520,7 @@ syscall_restart(unsigned long r0, unsigned long r19, 
 * all (if we get here from anything but a syscall return, it will be 0)

 */

static void

do_signal(struct pt_regs * regs, struct switch_stack * sw,

	  unsigned long r0, unsigned long r19)

do_signal(struct pt_regs *regs, unsigned long r0, unsigned long r19)

{

	siginfo_t info;

	int signr;
@@ -537,7 +537,7 @@ do_signal(struct pt_regs * regs, struct switch_stack * sw, 
		/* Whee!  Actually deliver the signal.  */

		if (r0)

			syscall_restart(r0, r19, regs, &ka);

		handle_signal(signr, &ka, &info, regs, sw);

		handle_signal(signr, &ka, &info, regs);

		if (single_stepping) 

			ptrace_set_bpt(current); /* re-set bpt */

		return;
@@ -568,15 +568,23 @@ do_signal(struct pt_regs * regs, struct switch_stack * sw, 
}



void

do_notify_resume(struct pt_regs *regs, struct switch_stack *sw,

		 unsigned long thread_info_flags,

do_work_pending(struct pt_regs *regs, unsigned long thread_flags,

		 unsigned long r0, unsigned long r19)

{

	if (thread_info_flags & _TIF_SIGPENDING)

		do_signal(regs, sw, r0, r19);



	if (thread_info_flags & _TIF_NOTIFY_RESUME) {

	do {

		if (thread_flags & _TIF_NEED_RESCHED) {

			schedule();

		} else {

			local_irq_enable();

			if (thread_flags & _TIF_SIGPENDING) {

				do_signal(regs, r0, r19);

				r0 = 0;

			} else {

				clear_thread_flag(TIF_NOTIFY_RESUME);

				tracehook_notify_resume(regs);

			}

		}

		local_irq_disable();

		thread_flags = current_thread_info()->flags;

	} while (thread_flags & _TIF_WORK_MASK);

}

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