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x86/boot/compressed: Move 32-bit entrypoint code into .text section

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Move the code that stores the arguments passed to the EFI entrypoint
into the .text section, so that it can be moved into a separate
compilation unit in a subsequent patch.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20221122161017.2426828-3-ardb@kernel.org
This commit is contained in:
Ard Biesheuvel 2022-11-22 17:10:02 +01:00 committed by Borislav Petkov
parent cb8bda8ad4
commit e2ab9eab32
1 changed files with 34 additions and 14 deletions
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48
arch/x86/boot/compressed/head_64.S
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@ -303,24 +303,41 @@ SYM_FUNC_START(efi32_stub_entry)
popl %ecx
popl %edx
popl %esi
jmp efi32_entry
SYM_FUNC_END(efi32_stub_entry)
.text
/*
* This is the common EFI stub entry point for mixed mode.
*
* Arguments: %ecx image handle
* %edx EFI system table pointer
* %esi struct bootparams pointer (or NULL when not using
* the EFI handover protocol)
*
* Since this is the point of no return for ordinary execution, no registers
* are considered live except for the function parameters. [Note that the EFI
* stub may still exit and return to the firmware using the Exit() EFI boot
* service.]
*/
SYM_FUNC_START_LOCAL(efi32_entry)
call 1f
1: pop %ebp
subl $ rva(1b), %ebp
movl %esi, rva(efi32_boot_args+8)(%ebp)
SYM_INNER_LABEL(efi32_pe_stub_entry, SYM_L_LOCAL)
movl %ecx, rva(efi32_boot_args)(%ebp)
movl %edx, rva(efi32_boot_args+4)(%ebp)
movb $0, rva(efi_is64)(%ebp)
1: pop %ebx
/* Save firmware GDTR and code/data selectors */
sgdtl rva(efi32_boot_gdt)(%ebp)
movw %cs, rva(efi32_boot_cs)(%ebp)
movw %ds, rva(efi32_boot_ds)(%ebp)
sgdtl (efi32_boot_gdt - 1b)(%ebx)
movw %cs, (efi32_boot_cs - 1b)(%ebx)
movw %ds, (efi32_boot_ds - 1b)(%ebx)
/* Store firmware IDT descriptor */
sidtl rva(efi32_boot_idt)(%ebp)
sidtl (efi32_boot_idt - 1b)(%ebx)
/* Store boot arguments */
leal (efi32_boot_args - 1b)(%ebx), %ebx
movl %ecx, 0(%ebx)
movl %edx, 4(%ebx)
movl %esi, 8(%ebx)
movb $0x0, 12(%ebx) // efi_is64
/* Disable paging */
movl %cr0, %eax
@ -328,7 +345,8 @@ SYM_INNER_LABEL(efi32_pe_stub_entry, SYM_L_LOCAL)
movl %eax, %cr0
jmp startup_32
SYM_FUNC_END(efi32_stub_entry)
SYM_FUNC_END(efi32_entry)
__HEAD
#endif
.code64
@ -831,7 +849,9 @@ SYM_FUNC_START(efi32_pe_entry)
*/
subl %esi, %ebx
movl %ebx, rva(image_offset)(%ebp) // save image_offset
jmp efi32_pe_stub_entry
xorl %esi, %esi
jmp efi32_entry // pass %ecx, %edx, %esi
// no other registers remain live
2: popl %edi // restore callee-save registers
popl %ebx