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Commit c73e36b7 authored by Denys Vlasenko's avatar Denys Vlasenko Committed by Ingo Molnar
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x86/asm/entry/32: Replace RESTORE_RSI_RDI with open-coded 32-bit reads 



This doesn't change much, but uses shorter 32-bit insns:

        -48 8b 74 24 68         mov    0x68(%rsp),%rsi
        -48 8b 7c 24 70         mov    0x70(%rsp),%rdi
        -48 8b 54 24 60         mov    0x60(%rsp),%rdx
        +8b 54 24 60            mov    0x60(%rsp),%edx
        +8b 74 24 68            mov    0x68(%rsp),%esi
        +8b 7c 24 70            mov    0x70(%rsp),%edi

and does the loads in pt_regs order.

Since these are the only uses of RESTORE_RSI_RDI[_RDX], drop
these macros.

Signed-off-by: default avatarDenys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1435954742-2545-1-git-send-email-dvlasenk@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 1c4c7159

arch/x86/entry/calling.h

+0 −6
Original line number Diff line number Diff line
@@ -193,12 +193,6 @@ For 32-bit we have the following conventions - kernel is built with 
	.macro RESTORE_C_REGS_EXCEPT_RCX_R11

	RESTORE_C_REGS_HELPER 1,0,0,1,1

	.endm

	.macro RESTORE_RSI_RDI

	RESTORE_C_REGS_HELPER 0,0,0,0,0

	.endm

	.macro RESTORE_RSI_RDI_RDX

	RESTORE_C_REGS_HELPER 0,0,0,0,1

	.endm



	.macro REMOVE_PT_GPREGS_FROM_STACK addskip=0

	subq $-(15*8+\addskip), %rsp

arch/x86/entry/entry_64_compat.S

+5 −2
Original line number Diff line number Diff line
@@ -140,7 +140,8 @@ sysexit_from_sys_call: 
	 */

	andl	$~TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)

	movl	RIP(%rsp), %ecx		/* User %eip */

	RESTORE_RSI_RDI

	movl	RSI(%rsp), %esi

	movl	RDI(%rsp), %edi

	xorl	%edx, %edx		/* Do not leak kernel information */

	xorq	%r8, %r8

	xorq	%r9, %r9
@@ -366,7 +367,9 @@ cstar_dispatch: 


sysretl_from_sys_call:

	andl	$~TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)

	RESTORE_RSI_RDI_RDX

	movl	RDX(%rsp), %edx

	movl	RSI(%rsp), %esi

	movl	RDI(%rsp), %edi

	movl	RIP(%rsp), %ecx

	movl	EFLAGS(%rsp), %r11d

	xorq	%r10, %r10