6.1-stable review patch. If anyone has any objections, please let me know.
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From: Ard Biesheuvel ardb@kernel.org
commit e2ab9eab324cdf240de89741e4a1aa79919f0196 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/boot/compressed/head_64.S | 48 ++++++++++++++++++++++++++----------- 1 file changed, 34 insertions(+), 14 deletions(-)
--- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -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 movl %eax, %cr0
jmp startup_32 -SYM_FUNC_END(efi32_stub_entry) +SYM_FUNC_END(efi32_entry) + __HEAD #endif
.code64 @@ -847,7 +865,9 @@ 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