Commit 5d73fc70 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
Browse files

x86/entry/32: Migrate to C exit path 



This removes the hybrid asm-and-C implementation of exit work.

Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/2baa438619ea6c027b40ec9fceacca52f09c74d09.1438378274.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent c5f69fde

arch/x86/entry/entry_32.S

+11 −51
Original line number Diff line number Diff line
@@ -256,14 +256,10 @@ ret_from_intr: 


ENTRY(resume_userspace)

	LOCKDEP_SYS_EXIT

	DISABLE_INTERRUPTS(CLBR_ANY)		# make sure we don't miss an interrupt

						# setting need_resched or sigpending

						# between sampling and the iret

	DISABLE_INTERRUPTS(CLBR_ANY)

	TRACE_IRQS_OFF

	movl	TI_flags(%ebp), %ecx

	andl	$_TIF_WORK_MASK, %ecx		# is there any work to be done on

						# int/exception return?

	jne	work_pending

	movl	%esp, %eax

	call	prepare_exit_to_usermode

	jmp	restore_all

END(ret_from_exception)
@@ -341,7 +337,7 @@ sysenter_after_call: 
	TRACE_IRQS_OFF

	movl	TI_flags(%ebp), %ecx

	testl	$_TIF_ALLWORK_MASK, %ecx

	jnz	syscall_exit_work

	jnz	syscall_exit_work_irqs_off

sysenter_exit:

/* if something modifies registers it must also disable sysexit */

	movl	PT_EIP(%esp), %edx
@@ -377,13 +373,7 @@ syscall_after_call: 
	movl	%eax, PT_EAX(%esp)		# store the return value

syscall_exit:

	LOCKDEP_SYS_EXIT

	DISABLE_INTERRUPTS(CLBR_ANY)		# make sure we don't miss an interrupt

						# setting need_resched or sigpending

						# between sampling and the iret

	TRACE_IRQS_OFF

	movl	TI_flags(%ebp), %ecx

	testl	$_TIF_ALLWORK_MASK, %ecx	# current->work

	jnz	syscall_exit_work

	jmp	syscall_exit_work



restore_all:

	TRACE_IRQS_IRET
@@ -460,35 +450,6 @@ ldt_ss: 
#endif

ENDPROC(entry_INT80_32)



	# perform work that needs to be done immediately before resumption

	ALIGN

work_pending:

	testb	$_TIF_NEED_RESCHED, %cl

	jz	work_notifysig

work_resched:

	call	schedule

	LOCKDEP_SYS_EXIT

	DISABLE_INTERRUPTS(CLBR_ANY)		# make sure we don't miss an interrupt

						# setting need_resched or sigpending

						# between sampling and the iret

	TRACE_IRQS_OFF

	movl	TI_flags(%ebp), %ecx

	andl	$_TIF_WORK_MASK, %ecx		# is there any work to be done other

						# than syscall tracing?

	jz	restore_all

	testb	$_TIF_NEED_RESCHED, %cl

	jnz	work_resched



work_notifysig:					# deal with pending signals and

						# notify-resume requests

	TRACE_IRQS_ON

	ENABLE_INTERRUPTS(CLBR_NONE)

	movl	%esp, %eax

	xorl	%edx, %edx

	call	do_notify_resume

	jmp	resume_userspace

END(work_pending)



	# perform syscall exit tracing

	ALIGN

syscall_trace_entry:
@@ -503,15 +464,14 @@ END(syscall_trace_entry) 


	# perform syscall exit tracing

	ALIGN

syscall_exit_work:

	testl	$_TIF_WORK_SYSCALL_EXIT, %ecx

	jz	work_pending

syscall_exit_work_irqs_off:

	TRACE_IRQS_ON

	ENABLE_INTERRUPTS(CLBR_ANY)		# could let syscall_trace_leave() call

						# schedule() instead

	ENABLE_INTERRUPTS(CLBR_ANY)



syscall_exit_work:

	movl	%esp, %eax

	call	syscall_trace_leave

	jmp	resume_userspace

	call	syscall_return_slowpath

	jmp	restore_all

END(syscall_exit_work)



syscall_fault:

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