Messages in this thread Patch in this message | | | From | Uros Bizjak <> | Subject | [PATCH v2] x86/boot/64: Use TEST %reg,%reg instead of CMP $0,%reg | Date | Thu, 29 Oct 2020 17:02:58 +0100 |
| |
Use TEST %reg,%reg which sets the zero flag in the same way as CMP $0,%reg, but the encoding uses one byte less.
v2: Correct commit subject
Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Reviewed-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Uros Bizjak <ubizjak@gmail.com> --- arch/x86/boot/compressed/head_64.S | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 017de6cc87dc..e94874f4bbc1 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -241,12 +241,12 @@ SYM_FUNC_START(startup_32) leal rva(startup_64)(%ebp), %eax #ifdef CONFIG_EFI_MIXED movl rva(efi32_boot_args)(%ebp), %edi - cmp $0, %edi + testl %edi, %edi jz 1f leal rva(efi64_stub_entry)(%ebp), %eax movl rva(efi32_boot_args+4)(%ebp), %esi movl rva(efi32_boot_args+8)(%ebp), %edx // saved bootparams pointer - cmpl $0, %edx + testl %edx, %edx jnz 1f /* * efi_pe_entry uses MS calling convention, which requires 32 bytes of @@ -592,7 +592,7 @@ SYM_CODE_START(trampoline_32bit_src) movl %eax, %cr0 /* Check what paging mode we want to be in after the trampoline */ - cmpl $0, %edx + testl %edx, %edx jz 1f /* We want 5-level paging: don't touch CR3 if it already points to 5-level page tables */ @@ -622,7 +622,7 @@ SYM_CODE_START(trampoline_32bit_src) /* Enable PAE and LA57 (if required) paging modes */ movl $X86_CR4_PAE, %eax - cmpl $0, %edx + testl %edx, %edx jz 1f orl $X86_CR4_LA57, %eax 1: -- 2.26.2
| |