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Commit 2fd37912 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Thomas Gleixner
Browse files

x86/entry/64: Simplify idtentry a little 



There's a bunch of duplication in idtentry, namely the
.Lfrom_usermode_switch_stack is a paranoid=0 copy of the normal flow.

Make this explicit by creating a idtentry_part helper macro.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: bp@alien8.de
Cc: torvalds@linux-foundation.org
Cc: hpa@zytor.com
Cc: dave.hansen@linux.intel.com
Cc: jgross@suse.com
Cc: zhe.he@windriver.com
Cc: joel@joelfernandes.org
Cc: devel@etsukata.com
Link: https://lkml.kernel.org/r/20190711114336.002429503@infradead.org
parent e67f1c11

arch/x86/entry/entry_64.S

+48 −54
Original line number Diff line number Diff line
@@ -864,6 +864,52 @@ apicinterrupt IRQ_WORK_VECTOR irq_work_interrupt smp_irq_work_interrupt 
 */

#define CPU_TSS_IST(x) PER_CPU_VAR(cpu_tss_rw) + (TSS_ist + (x) * 8)



.macro idtentry_part do_sym, has_error_code:req, paranoid:req, shift_ist=-1, ist_offset=0



	.if \paranoid

	call	paranoid_entry

	/* returned flag: ebx=0: need swapgs on exit, ebx=1: don't need it */

	.else

	call	error_entry

	.endif

	UNWIND_HINT_REGS



	.if \paranoid

	.if \shift_ist != -1

	TRACE_IRQS_OFF_DEBUG			/* reload IDT in case of recursion */

	.else

	TRACE_IRQS_OFF

	.endif

	.endif



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



	.if \has_error_code

	movq	ORIG_RAX(%rsp), %rsi		/* get error code */

	movq	$-1, ORIG_RAX(%rsp)		/* no syscall to restart */

	.else

	xorl	%esi, %esi			/* no error code */

	.endif



	.if \shift_ist != -1

	subq	$\ist_offset, CPU_TSS_IST(\shift_ist)

	.endif



	call	\do_sym



	.if \shift_ist != -1

	addq	$\ist_offset, CPU_TSS_IST(\shift_ist)

	.endif



	.if \paranoid

	/* this procedure expect "no swapgs" flag in ebx */

	jmp	paranoid_exit

	.else

	jmp	error_exit

	.endif



.endm



/**

 * idtentry - Generate an IDT entry stub

 * @sym:		Name of the generated entry point
@@ -934,47 +980,7 @@ ENTRY(\sym) 
.Lfrom_usermode_no_gap_\@:

	.endif



	.if \paranoid

	call	paranoid_entry

	.else

	call	error_entry

	.endif

	UNWIND_HINT_REGS

	/* returned flag: ebx=0: need swapgs on exit, ebx=1: don't need it */



	.if \paranoid

	.if \shift_ist != -1

	TRACE_IRQS_OFF_DEBUG			/* reload IDT in case of recursion */

	.else

	TRACE_IRQS_OFF

	.endif

	.endif



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



	.if \has_error_code

	movq	ORIG_RAX(%rsp), %rsi		/* get error code */

	movq	$-1, ORIG_RAX(%rsp)		/* no syscall to restart */

	.else

	xorl	%esi, %esi			/* no error code */

	.endif



	.if \shift_ist != -1

	subq	$\ist_offset, CPU_TSS_IST(\shift_ist)

	.endif



	call	\do_sym



	.if \shift_ist != -1

	addq	$\ist_offset, CPU_TSS_IST(\shift_ist)

	.endif



	/* these procedures expect "no swapgs" flag in ebx */

	.if \paranoid

	jmp	paranoid_exit

	.else

	jmp	error_exit

	.endif

	idtentry_part \do_sym, \has_error_code, \paranoid, \shift_ist, \ist_offset



	.if \paranoid == 1

	/*
@@ -983,21 +989,9 @@ ENTRY(\sym) 
	 * run in real process context if user_mode(regs).

	 */

.Lfrom_usermode_switch_stack_\@:

	call	error_entry



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



	.if \has_error_code

	movq	ORIG_RAX(%rsp), %rsi		/* get error code */

	movq	$-1, ORIG_RAX(%rsp)		/* no syscall to restart */

	.else

	xorl	%esi, %esi			/* no error code */

	idtentry_part \do_sym, \has_error_code, paranoid=0

	.endif



	call	\do_sym



	jmp	error_exit

	.endif

_ASM_NOKPROBE(\sym)

END(\sym)

.endm