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Commit 4d732138 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86/asm/entry/64: Clean up entry_64.S 



Make the 64-bit syscall entry code a bit more readable:

 - use consistent assembly coding style similar to the other entry_*.S files

 - remove old comments that are not true anymore

 - eliminate whitespace noise

 - use consistent vertical spacing

 - fix various comments

 - reorganize entry point generation tables to be more readable

No code changed:

  # arch/x86/entry/entry_64.o:

   text    data     bss     dec     hex filename
  12282       0       0   12282    2ffa entry_64.o.before
  12282       0       0   12282    2ffa entry_64.o.after

md5:
   cbab1f2d727a2a8a87618eeb79f391b7  entry_64.o.before.asm
   cbab1f2d727a2a8a87618eeb79f391b7  entry_64.o.after.asm

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 9dda1658

arch/x86/entry/entry_64.S

+404 −416
Original line number Diff line number Diff line
@@ -4,26 +4,20 @@ 
 *  Copyright (C) 1991, 1992  Linus Torvalds

 *  Copyright (C) 2000, 2001, 2002  Andi Kleen SuSE Labs

 *  Copyright (C) 2000  Pavel Machek <pavel@suse.cz>

 */



/*

 *

 * entry.S contains the system-call and fault low-level handling routines.

 *

 * Some of this is documented in Documentation/x86/entry_64.txt

 *

 * NOTE: This code handles signal-recognition, which happens every time

 * after an interrupt and after each system call.

 *

 * A note on terminology:

 * - iret frame:	Architecture defined interrupt frame from SS to RIP

 *			at the top of the kernel process stack.

 *

 * Some macro usage:

 * - ENTRY/END Define functions in the symbol table.

 * - TRACE_IRQ_* - Trace hard interrupt state for lock debugging.

 * - idtentry - Define exception entry points.

 * - ENTRY/END:		Define functions in the symbol table.

 * - TRACE_IRQ_*:	Trace hardirq state for lock debugging.

 * - idtentry:		Define exception entry points.

 */



#include <linux/linkage.h>

#include <asm/segment.h>

#include <asm/cache.h>
@@ -53,7 +47,6 @@ 
.code64

.section .entry.text, "ax"





#ifdef CONFIG_PARAVIRT

ENTRY(native_usergs_sysret64)

	swapgs
@@ -61,7 +54,6 @@ ENTRY(native_usergs_sysret64) 
ENDPROC(native_usergs_sysret64)

#endif /* CONFIG_PARAVIRT */





.macro TRACE_IRQS_IRETQ

#ifdef CONFIG_TRACE_IRQFLAGS

	bt	$9, EFLAGS(%rsp)		/* interrupts off? */
@@ -110,9 +102,9 @@ ENDPROC(native_usergs_sysret64) 
#endif



/*

 * 64bit SYSCALL instruction entry. Up to 6 arguments in registers.

 * 64-bit SYSCALL instruction entry. Up to 6 arguments in registers.

 *

 * 64bit SYSCALL saves rip to rcx, clears rflags.RF, then saves rflags to r11,

 * 64-bit SYSCALL saves rip to rcx, clears rflags.RF, then saves rflags to r11,

 * then loads new ss, cs, and rip from previously programmed MSRs.

 * rflags gets masked by a value from another MSR (so CLD and CLAC

 * are not needed). SYSCALL does not save anything on the stack
@@ -221,7 +213,7 @@ entry_SYSCALL_64_fastpath: 
	movq	EFLAGS(%rsp), %r11

	movq	RSP(%rsp), %rsp

	/*

	 * 64bit SYSRET restores rip from rcx,

	 * 64-bit SYSRET restores rip from rcx,

	 * rflags from r11 (but RF and VM bits are forced to 0),

	 * cs and ss are loaded from MSRs.

	 * Restoration of rflags re-enables interrupts.
@@ -294,9 +286,11 @@ GLOBAL(int_with_check) 
	andl	$~TS_COMPAT, TI_status(%rcx)

	jmp	syscall_return



	/* Either reschedule or signal or syscall exit tracking needed. */

	/* First do a reschedule test. */

	/* edx:	work, edi: workmask */

	/*

	 * Either reschedule or signal or syscall exit tracking needed.

	 * First do a reschedule test.

	 * edx:	work, edi: workmask

	 */

int_careful:

	bt	$TIF_NEED_RESCHED, %edx

	jnc	int_very_careful
@@ -318,7 +312,7 @@ int_very_careful: 
	testl	$_TIF_WORK_SYSCALL_EXIT, %edx

	jz	int_signal

	pushq	%rdi

	leaq 8(%rsp),%rdi	# &ptregs -> arg1

	leaq	8(%rsp), %rdi			/* &ptregs -> arg1 */

	call	syscall_trace_leave

	popq	%rdi

	andl	$~(_TIF_WORK_SYSCALL_EXIT|_TIF_SYSCALL_EMU), %edi
@@ -327,8 +321,8 @@ int_very_careful: 
int_signal:

	testl	$_TIF_DO_NOTIFY_MASK, %edx

	jz	1f

	movq %rsp,%rdi		# &ptregs -> arg1

	xorl %esi,%esi		# oldset -> arg2

	movq	%rsp, %rdi			/* &ptregs -> arg1 */

	xorl	%esi, %esi			/* oldset -> arg2 */

	call	do_notify_resume

1:	movl	$_TIF_WORK_MASK, %edi

int_restore_rest:
@@ -362,9 +356,11 @@ syscall_return: 
	.ifne __VIRTUAL_MASK_SHIFT - 47

	.error "virtual address width changed -- SYSRET checks need update"

	.endif



	/* Change top 16 bits to be the sign-extension of 47th bit */

	shl	$(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx

	sar	$(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx



	/* If this changed %rcx, it was not canonical */

	cmpq	%rcx, %r11

	jne	opportunistic_sysret_failed
@@ -505,13 +501,13 @@ ENTRY(ret_from_fork) 
	LOCK ; btr $TIF_FORK, TI_flags(%r8)



	pushq	$0x0002

	popfq				# reset kernel eflags

	popfq					/* reset kernel eflags */



	call schedule_tail			# rdi: 'prev' task parameter

	call	schedule_tail			/* rdi: 'prev' task parameter */



	RESTORE_EXTRA_REGS



	testb	$3, CS(%rsp)			# from kernel_thread?

	testb	$3, CS(%rsp)			/* from kernel_thread? */



	/*

	 * By the time we get here, we have no idea whether our pt_regs,
@@ -522,8 +518,10 @@ ENTRY(ret_from_fork) 
	 */

	jnz	int_ret_from_sys_call



	/* We came from kernel_thread */

	/* nb: we depend on RESTORE_EXTRA_REGS above */

	/*

	 * We came from kernel_thread

	 * nb: we depend on RESTORE_EXTRA_REGS above

	 */

	movq	%rbp, %rdi

	call	*%rbx

	movl	$0, RAX(%rsp)
@@ -617,9 +615,8 @@ ret_from_intr: 
	/* Interrupt came from user space */

retint_user:

	GET_THREAD_INFO(%rcx)

	/*

	 * %rcx: thread info. Interrupts off.

	 */



	/* %rcx: thread info. Interrupts are off. */

retint_with_reschedule:

	movl	$_TIF_WORK_MASK, %edi

retint_check:
@@ -643,7 +640,7 @@ retint_kernel: 
#ifdef CONFIG_PREEMPT

	/* Interrupts are off */

	/* Check if we need preemption */

	bt	$9,EFLAGS(%rsp)	/* interrupts were off? */

	bt	$9, EFLAGS(%rsp)		/* were interrupts off? */

	jnc	1f

0:	cmpl	$0, PER_CPU_VAR(__preempt_count)

	jnz	1f
@@ -732,8 +729,8 @@ retint_signal: 
	ENABLE_INTERRUPTS(CLBR_NONE)

	SAVE_EXTRA_REGS

	movq	$-1, ORIG_RAX(%rsp)

	xorl %esi,%esi		# oldset

	movq %rsp,%rdi		# &pt_regs

	xorl	%esi, %esi			/* oldset */

	movq	%rsp, %rdi			/* &pt_regs */

	call	do_notify_resume

	RESTORE_EXTRA_REGS

	DISABLE_INTERRUPTS(CLBR_NONE)
@@ -774,60 +771,45 @@ trace_apicinterrupt \num \sym 
.endm



#ifdef CONFIG_SMP

apicinterrupt3 IRQ_MOVE_CLEANUP_VECTOR \

	irq_move_cleanup_interrupt smp_irq_move_cleanup_interrupt

apicinterrupt3 REBOOT_VECTOR \

	reboot_interrupt smp_reboot_interrupt

apicinterrupt3 IRQ_MOVE_CLEANUP_VECTOR		irq_move_cleanup_interrupt	smp_irq_move_cleanup_interrupt

apicinterrupt3 REBOOT_VECTOR			reboot_interrupt		smp_reboot_interrupt

#endif



#ifdef CONFIG_X86_UV

apicinterrupt3 UV_BAU_MESSAGE \

	uv_bau_message_intr1 uv_bau_message_interrupt

apicinterrupt3 UV_BAU_MESSAGE			uv_bau_message_intr1		uv_bau_message_interrupt

#endif

apicinterrupt LOCAL_TIMER_VECTOR \

	apic_timer_interrupt smp_apic_timer_interrupt

apicinterrupt X86_PLATFORM_IPI_VECTOR \

	x86_platform_ipi smp_x86_platform_ipi



apicinterrupt LOCAL_TIMER_VECTOR		apic_timer_interrupt		smp_apic_timer_interrupt

apicinterrupt X86_PLATFORM_IPI_VECTOR		x86_platform_ipi		smp_x86_platform_ipi



#ifdef CONFIG_HAVE_KVM

apicinterrupt3 POSTED_INTR_VECTOR \

	kvm_posted_intr_ipi smp_kvm_posted_intr_ipi

apicinterrupt3 POSTED_INTR_WAKEUP_VECTOR \

	kvm_posted_intr_wakeup_ipi smp_kvm_posted_intr_wakeup_ipi

apicinterrupt3 POSTED_INTR_VECTOR		kvm_posted_intr_ipi		smp_kvm_posted_intr_ipi

apicinterrupt3 POSTED_INTR_WAKEUP_VECTOR	kvm_posted_intr_wakeup_ipi	smp_kvm_posted_intr_wakeup_ipi

#endif



#ifdef CONFIG_X86_MCE_THRESHOLD

apicinterrupt THRESHOLD_APIC_VECTOR \

	threshold_interrupt smp_threshold_interrupt

apicinterrupt THRESHOLD_APIC_VECTOR		threshold_interrupt		smp_threshold_interrupt

#endif



#ifdef CONFIG_X86_MCE_AMD

apicinterrupt DEFERRED_ERROR_VECTOR \

	deferred_error_interrupt smp_deferred_error_interrupt

apicinterrupt DEFERRED_ERROR_VECTOR		deferred_error_interrupt	smp_deferred_error_interrupt

#endif



#ifdef CONFIG_X86_THERMAL_VECTOR

apicinterrupt THERMAL_APIC_VECTOR \

	thermal_interrupt smp_thermal_interrupt

apicinterrupt THERMAL_APIC_VECTOR		thermal_interrupt		smp_thermal_interrupt

#endif



#ifdef CONFIG_SMP

apicinterrupt CALL_FUNCTION_SINGLE_VECTOR \

	call_function_single_interrupt smp_call_function_single_interrupt

apicinterrupt CALL_FUNCTION_VECTOR \

	call_function_interrupt smp_call_function_interrupt

apicinterrupt RESCHEDULE_VECTOR \

	reschedule_interrupt smp_reschedule_interrupt

apicinterrupt CALL_FUNCTION_SINGLE_VECTOR	call_function_single_interrupt	smp_call_function_single_interrupt

apicinterrupt CALL_FUNCTION_VECTOR		call_function_interrupt		smp_call_function_interrupt

apicinterrupt RESCHEDULE_VECTOR			reschedule_interrupt		smp_reschedule_interrupt

#endif



apicinterrupt ERROR_APIC_VECTOR \

	error_interrupt smp_error_interrupt

apicinterrupt SPURIOUS_APIC_VECTOR \

	spurious_interrupt smp_spurious_interrupt

apicinterrupt ERROR_APIC_VECTOR			error_interrupt			smp_error_interrupt

apicinterrupt SPURIOUS_APIC_VECTOR		spurious_interrupt		smp_spurious_interrupt



#ifdef CONFIG_IRQ_WORK

apicinterrupt IRQ_WORK_VECTOR \

	irq_work_interrupt smp_irq_work_interrupt

apicinterrupt IRQ_WORK_VECTOR			irq_work_interrupt		smp_irq_work_interrupt

#endif



/*
@@ -853,8 +835,8 @@ ENTRY(\sym) 


	.if \paranoid

	.if \paranoid == 1

	testb	$3, CS(%rsp)		/* If coming from userspace, switch */

	jnz 1f				/* stacks. */

	testb	$3, CS(%rsp)			/* If coming from userspace, switch stacks */

	jnz	1f

	.endif

	call	paranoid_entry

	.else
@@ -952,8 +934,10 @@ idtentry alignment_check do_alignment_check has_error_code=1 
idtentry simd_coprocessor_error		do_simd_coprocessor_error	has_error_code=0





	/* Reload gs selector with exception handling */

	/* edi:  new selector */

	/*

	 * Reload gs selector with exception handling

	 * edi:  new selector

	 */

ENTRY(native_load_gs_index)

	pushfq

	DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI)
@@ -982,7 +966,7 @@ ENTRY(do_softirq_own_stack) 
	mov	%rsp, %rbp

	incl	PER_CPU_VAR(irq_count)

	cmove	PER_CPU_VAR(irq_stack_ptr), %rsp

	push  %rbp			# backlink for old unwinder

	push	%rbp				/* frame pointer backlink */

	call	__do_softirq

	leaveq

	decl	PER_CPU_VAR(irq_count)
@@ -1005,16 +989,17 @@ idtentry xen_hypervisor_callback xen_do_hypervisor_callback has_error_code=0 
 * existing activation in its critical region -- if so, we pop the current

 * activation and restart the handler using the previous one.

 */

ENTRY(xen_do_hypervisor_callback)   # do_hypervisor_callback(struct *pt_regs)

ENTRY(xen_do_hypervisor_callback)		/* do_hypervisor_callback(struct *pt_regs) */



/*

 * Since we don't modify %rdi, evtchn_do_upall(struct *pt_regs) will

 * see the correct pointer to the pt_regs

 */

	movq %rdi, %rsp            # we don't return, adjust the stack frame

	movq	%rdi, %rsp			/* we don't return, adjust the stack frame */

11:	incl	PER_CPU_VAR(irq_count)

	movq	%rsp, %rbp

	cmovzq	PER_CPU_VAR(irq_stack_ptr), %rsp

	pushq %rbp			# backlink for old unwinder

	pushq	%rbp				/* frame pointer backlink */

	call	xen_evtchn_do_upcall

	popq	%rsp

	decl	PER_CPU_VAR(irq_count)
@@ -1082,16 +1067,20 @@ apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \ 
idtentry debug			do_debug		has_error_code=0	paranoid=1 shift_ist=DEBUG_STACK

idtentry int3			do_int3			has_error_code=0	paranoid=1 shift_ist=DEBUG_STACK

idtentry stack_segment		do_stack_segment	has_error_code=1



#ifdef CONFIG_XEN

idtentry xen_debug		do_debug		has_error_code=0

idtentry xen_int3		do_int3			has_error_code=0

idtentry xen_stack_segment	do_stack_segment	has_error_code=1

#endif



idtentry general_protection	do_general_protection	has_error_code=1

trace_idtentry page_fault	do_page_fault		has_error_code=1



#ifdef CONFIG_KVM_GUEST

idtentry async_page_fault	do_async_page_fault	has_error_code=1

#endif



#ifdef CONFIG_X86_MCE

idtentry machine_check					has_error_code=0	paranoid=1 do_sym=*machine_check_vector(%rip)

#endif
@@ -1124,8 +1113,9 @@ END(paranoid_entry) 
 * in syscall entry), so checking for preemption here would

 * be complicated.  Fortunately, we there's no good reason

 * to try to handle preemption here.

 *

 * On entry, ebx is "no swapgs" flag (1: don't need swapgs, 0: need it)

 */

/* On entry, ebx is "no swapgs" flag (1: don't need swapgs, 0: need it) */

ENTRY(paranoid_exit)

	DISABLE_INTERRUPTS(CLBR_NONE)

	TRACE_IRQS_OFF_DEBUG
@@ -1268,6 +1258,7 @@ ENTRY(nmi) 
	cmpq	%rdx, 4*8(%rsp)

	/* If the stack pointer is above the NMI stack, this is a normal NMI */

	ja	first_nmi



	subq	$EXCEPTION_STKSZ, %rdx

	cmpq	%rdx, 4*8(%rsp)

	/* If it is below the NMI stack, it is a normal NMI */
@@ -1349,9 +1340,7 @@ first_nmi: 
	/* Set the NMI executing variable on the stack. */

	pushq	$1



	/*

	 * Leave room for the "copied" frame

	 */

	/* Leave room for the "copied" frame */

	subq	$(5*8), %rsp



	/* Copy the stack frame to the Saved frame */
@@ -1444,4 +1433,3 @@ ENTRY(ignore_sysret) 
	mov	$-ENOSYS, %eax

	sysret

END(ignore_sysret)