diff options
| author | Ard Biesheuvel <ardb@kernel.org> | 2022-11-22 17:10:08 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-03-06 14:45:13 +0000 |
| commit | 88035744b91a187bcc23253a73ef3b1ccc08a2f9 (patch) | |
| tree | 6a68bbf26e09d7bcb64099ec7720de86e7bc1ca0 | |
| parent | ef12d049fa7b429a0f1842307e921da30ff2e97b (diff) | |
| download | linux-88035744b91a187bcc23253a73ef3b1ccc08a2f9.tar.gz | |
x86/boot/compressed: Simplify IDT/GDT preserve/restore in the EFI thunk
commit 630f337f0c4fd80390e8600adcab31550aea33df upstream.
Tweak the asm and remove some redundant instructions. While at it,
fix the associated comment for style and correctness.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20221122161017.2426828-9-ardb@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/boot/compressed/efi_mixed.S | 20 |
1 files changed, 7 insertions, 13 deletions
diff --git a/arch/x86/boot/compressed/efi_mixed.S b/arch/x86/boot/compressed/efi_mixed.S index 8844d8ed4b1c75..8b02e507d3bb05 100644 --- a/arch/x86/boot/compressed/efi_mixed.S +++ b/arch/x86/boot/compressed/efi_mixed.S @@ -96,24 +96,20 @@ SYM_FUNC_START(__efi64_thunk) leaq 0x20(%rsp), %rbx sgdt (%rbx) - - addq $16, %rbx - sidt (%rbx) + sidt 16(%rbx) leaq 1f(%rip), %rbp /* - * Switch to IDT and GDT with 32-bit segments. This is the firmware GDT - * and IDT that was installed when the kernel started executing. The - * pointers were saved by the efi32_entry() routine below. + * Switch to IDT and GDT with 32-bit segments. These are the firmware + * GDT and IDT that were installed when the kernel started executing. + * The pointers were saved by the efi32_entry() routine below. * * Pass the saved DS selector to the 32-bit code, and use far return to * restore the saved CS selector. */ - leaq efi32_boot_idt(%rip), %rax - lidt (%rax) - leaq efi32_boot_gdt(%rip), %rax - lgdt (%rax) + lidt efi32_boot_idt(%rip) + lgdt efi32_boot_gdt(%rip) movzwl efi32_boot_ds(%rip), %edx movzwq efi32_boot_cs(%rip), %rax @@ -187,9 +183,7 @@ SYM_FUNC_START_LOCAL(efi_enter32) */ cli - lidtl (%ebx) - subl $16, %ebx - + lidtl 16(%ebx) lgdtl (%ebx) movl %cr4, %eax |