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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/x86/power/hibernate_asm_32.S
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/* SPDX-License-Identifier: GPL-2.0 */

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/*

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 * This may not use any stack, nor any variable that is not "NoSave":

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 *

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 * Its rewriting one kernel image with another. What is stack in "old"

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 * image could very well be data page in "new" image, and overwriting

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 * your own stack under you is bad idea.

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 */

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#include <linux/linkage.h>

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#include <asm/segment.h>

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#include <asm/page_types.h>

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#include <asm/asm-offsets.h>

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#include <asm/processor-flags.h>

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#include <asm/frame.h>

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.text

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SYM_FUNC_START(swsusp_arch_suspend)

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	movl %esp, saved_context_esp

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	movl %ebx, saved_context_ebx

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	movl %ebp, saved_context_ebp

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	movl %esi, saved_context_esi

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	movl %edi, saved_context_edi

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	pushfl

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	popl saved_context_eflags

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	/* save cr3 */

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	movl	%cr3, %eax

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	movl	%eax, restore_cr3

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	FRAME_BEGIN

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	call swsusp_save

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	FRAME_END

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	RET

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SYM_FUNC_END(swsusp_arch_suspend)

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SYM_CODE_START(restore_image)

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	/* prepare to jump to the image kernel */

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	movl	restore_jump_address, %ebx

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	movl	restore_cr3, %ebp

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	movl	mmu_cr4_features, %ecx

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	/* jump to relocated restore code */

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	movl	relocated_restore_code, %eax

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	jmpl	*%eax

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SYM_CODE_END(restore_image)

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/* code below has been relocated to a safe page */

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SYM_CODE_START(core_restore_code)

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	movl	temp_pgt, %eax

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	movl	%eax, %cr3

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	jecxz	1f	# cr4 Pentium and higher, skip if zero

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	andl	$~(X86_CR4_PGE), %ecx

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	movl	%ecx, %cr4;  # turn off PGE

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	movl	%cr3, %eax;  # flush TLB

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	movl	%eax, %cr3

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1:

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	movl	restore_pblist, %edx

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	.p2align 4,,7

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copy_loop:

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	testl	%edx, %edx

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	jz	done

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	movl	pbe_address(%edx), %esi

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	movl	pbe_orig_address(%edx), %edi

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	movl	$(PAGE_SIZE >> 2), %ecx

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	rep movsl

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	movl	pbe_next(%edx), %edx

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	jmp	copy_loop

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	.p2align 4,,7

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done:

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	jmpl	*%ebx

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SYM_CODE_END(core_restore_code)

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	/* code below belongs to the image kernel */

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	.align PAGE_SIZE

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SYM_FUNC_START(restore_registers)

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	/* go back to the original page tables */

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	movl	%ebp, %cr3

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	movl	mmu_cr4_features, %ecx

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	jecxz	1f	# cr4 Pentium and higher, skip if zero

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	movl	%ecx, %cr4;  # turn PGE back on

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1:

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	movl saved_context_esp, %esp

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	movl saved_context_ebp, %ebp

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	movl saved_context_ebx, %ebx

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	movl saved_context_esi, %esi

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	movl saved_context_edi, %edi

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	pushl saved_context_eflags

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	popfl

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	/* Saved in save_processor_state. */

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	movl $saved_context, %eax

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	lgdt saved_context_gdt_desc(%eax)

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	xorl	%eax, %eax

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	/* tell the hibernation core that we've just restored the memory */

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	movl	%eax, in_suspend

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	RET

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SYM_FUNC_END(restore_registers)

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