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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/x86/lib/msr-reg.S
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/* SPDX-License-Identifier: GPL-2.0 */

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#include <linux/linkage.h>

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#include <linux/errno.h>

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#include <linux/cfi_types.h>

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#include <asm/asm.h>

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#include <asm/msr.h>

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#ifdef CONFIG_X86_64

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/*

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 * int {rdmsr,wrmsr}_safe_regs(u32 gprs[8]);

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 *

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 * reg layout: u32 gprs[eax, ecx, edx, ebx, esp, ebp, esi, edi]

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 *

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 */

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.macro op_safe_regs op

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SYM_TYPED_FUNC_START(\op\()_safe_regs)

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	pushq %rbx

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	pushq %r12

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	movq	%rdi, %r10	/* Save pointer */

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	xorl	%r11d, %r11d	/* Return value */

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	movl    (%rdi), %eax

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	movl    4(%rdi), %ecx

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	movl    8(%rdi), %edx

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	movl    12(%rdi), %ebx

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	movl    20(%rdi), %r12d

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	movl    24(%rdi), %esi

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	movl    28(%rdi), %edi

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1:	\op

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2:	movl    %eax, (%r10)

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	movl	%r11d, %eax	/* Return value */

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	movl    %ecx, 4(%r10)

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	movl    %edx, 8(%r10)

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	movl    %ebx, 12(%r10)

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	movl    %r12d, 20(%r10)

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	movl    %esi, 24(%r10)

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	movl    %edi, 28(%r10)

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	popq %r12

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	popq %rbx

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	RET

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3:

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	movl    $-EIO, %r11d

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	jmp     2b

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	_ASM_EXTABLE(1b, 3b)

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SYM_FUNC_END(\op\()_safe_regs)

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.endm

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#else /* X86_32 */

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.macro op_safe_regs op

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SYM_FUNC_START(\op\()_safe_regs)

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	pushl %ebx

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	pushl %ebp

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	pushl %esi

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	pushl %edi

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	pushl $0              /* Return value */

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	pushl %eax

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	movl    4(%eax), %ecx

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	movl    8(%eax), %edx

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	movl    12(%eax), %ebx

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	movl    20(%eax), %ebp

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	movl    24(%eax), %esi

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	movl    28(%eax), %edi

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	movl    (%eax), %eax

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1:	\op

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2:	pushl %eax

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	movl    4(%esp), %eax

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	popl (%eax)

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	addl    $4, %esp

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	movl    %ecx, 4(%eax)

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	movl    %edx, 8(%eax)

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	movl    %ebx, 12(%eax)

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	movl    %ebp, 20(%eax)

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	movl    %esi, 24(%eax)

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	movl    %edi, 28(%eax)

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	popl %eax

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	popl %edi

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	popl %esi

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	popl %ebp

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	popl %ebx

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	RET

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3:

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	movl    $-EIO, 4(%esp)

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	jmp     2b

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	_ASM_EXTABLE(1b, 3b)

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SYM_FUNC_END(\op\()_safe_regs)

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.endm

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#endif

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op_safe_regs rdmsr

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op_safe_regs wrmsr

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