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Commit c38e5038 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86/asm/entry/64: Rename 'old_rsp' to 'rsp_scratch' 



Make clear that the usage of PER_CPU(old_rsp) is purely temporary,
by renaming it to 'rsp_scratch'.

Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
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: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 7fcb3bc3

arch/x86/kernel/entry_64.S

+5 −5
Original line number Diff line number Diff line
@@ -237,16 +237,16 @@ ENTRY(system_call) 
GLOBAL(system_call_after_swapgs)



	/*

	 * We use 'old_rsp' as a scratch register, hence this block must execute

	 * We use 'rsp_scratch' as a scratch register, hence this block must execute

	 * atomically in the face of possible interrupt-driven task preemption,

	 * so we can enable interrupts only after we're done with using old_rsp:

	 * so we can enable interrupts only after we're done with using rsp_scratch:

	 */

	movq	%rsp,PER_CPU_VAR(old_rsp)

	movq	%rsp,PER_CPU_VAR(rsp_scratch)

	/* kernel_stack is set so that 5 slots (iret frame) are preallocated */

	movq	PER_CPU_VAR(kernel_stack),%rsp

	ALLOC_PT_GPREGS_ON_STACK 8		/* +8: space for orig_ax */

	movq	%rcx,RIP(%rsp)

	movq	PER_CPU_VAR(old_rsp),%rcx

	movq	PER_CPU_VAR(rsp_scratch),%rcx

	movq	%r11,EFLAGS(%rsp)

	movq	%rcx,RSP(%rsp)

	/*
@@ -657,7 +657,7 @@ common_interrupt: 
	ASM_CLAC

	addq $-0x80,(%rsp)		/* Adjust vector to [-256,-1] range */

	interrupt do_IRQ

	/* 0(%rsp): old_rsp */

	/* 0(%rsp): rsp_scratch */

ret_from_intr:

	DISABLE_INTERRUPTS(CLBR_NONE)

	TRACE_IRQS_OFF

arch/x86/kernel/process_64.c

+1 −1
Original line number Diff line number Diff line
@@ -52,7 +52,7 @@ 


asmlinkage extern void ret_from_fork(void);



__visible DEFINE_PER_CPU(unsigned long, old_rsp);

__visible DEFINE_PER_CPU(unsigned long, rsp_scratch);



/* Prints also some state that isn't saved in the pt_regs */

void __show_regs(struct pt_regs *regs, int all)

arch/x86/xen/xen-asm_64.S

+4 −4
Original line number Diff line number Diff line
@@ -68,11 +68,11 @@ ENTRY(xen_sysret64) 
	 * We're already on the usermode stack at this point, but

	 * still with the kernel gs, so we can easily switch back

	 */

	movq %rsp, PER_CPU_VAR(old_rsp)

	movq %rsp, PER_CPU_VAR(rsp_scratch)

	movq PER_CPU_VAR(kernel_stack), %rsp



	pushq $__USER_DS

	pushq PER_CPU_VAR(old_rsp)

	pushq PER_CPU_VAR(rsp_scratch)

	pushq %r11

	pushq $__USER_CS

	pushq %rcx
@@ -87,11 +87,11 @@ ENTRY(xen_sysret32) 
	 * We're already on the usermode stack at this point, but

	 * still with the kernel gs, so we can easily switch back

	 */

	movq %rsp, PER_CPU_VAR(old_rsp)

	movq %rsp, PER_CPU_VAR(rsp_scratch)

	movq PER_CPU_VAR(kernel_stack), %rsp



	pushq $__USER32_DS

	pushq PER_CPU_VAR(old_rsp)

	pushq PER_CPU_VAR(rsp_scratch)

	pushq %r11

	pushq $__USER32_CS

	pushq %rcx