mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-08-05 16:54:27 +00:00
42c782fae3
Minimum version of binutils required to compile the kernel is 2.25. This version correctly handles the "rep" prefixes, so it is possible to remove the semicolon, which was used to support ancient versions of GNU as. Due to the semicolon, the compiler considers "rep; insn" (or its alternate "rep\n\tinsn" form) as two separate instructions. Removing the semicolon makes asm length calculations more accurate, consequently making scheduling and inlining decisions of the compiler more accurate. Removing the semicolon also enables assembler checks involving "rep" prefixes. Trying to assemble e.g. "rep addl %eax, %ebx" results in: Error: invalid instruction `add' after `rep' Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Pavel Machek <pavel@kernel.org> Cc: Rafael J. Wysocki <rafael@kernel.org> Link: https://lore.kernel.org/r/20250418071437.4144391-2-ubizjak@gmail.com
111 lines
2.4 KiB
ArmAsm
111 lines
2.4 KiB
ArmAsm
/* 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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