The following commit has been merged into the x86/boot branch of tip:
Commit-ID: adf6819278ba34be1d29ffcdca5c2ccd2123f667
Gitweb: https://git.kernel.org/tip/adf6819278ba34be1d29ffcdca5c2ccd2123f667
Author: Uros Bizjak <ubizjak@xxxxxxxxx>
AuthorDate: Wed, 26 Feb 2025 16:36:56 +01:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Thu, 27 Feb 2025 10:14:00 +01:00
x86/bootflag: Micro-optimize sbf_write()
Change parity bit with XOR when !parity instead of masking bit out
and conditionally setting it when !parity.
Saves a couple of bytes in the object file.
Co-developed-by: "H. Peter Anvin" <hpa@xxxxxxxxx>
Signed-off-by: "H. Peter Anvin" <hpa@xxxxxxxxx>
Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20250226153709.6370-1-ubizjak@xxxxxxxxx
---
arch/x86/kernel/bootflag.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/x86/kernel/bootflag.c b/arch/x86/kernel/bootflag.c
index 4d89a2d..b935c3e 100644
--- a/arch/x86/kernel/bootflag.c
+++ b/arch/x86/kernel/bootflag.c
@@ -38,9 +38,8 @@ static void __init sbf_write(u8 v)
unsigned long flags;
if (sbf_port != -1) {
- v &= ~SBF_PARITY;
if (!parity(v))
- v |= SBF_PARITY;
+ v ^= SBF_PARITY;
printk(KERN_INFO "Simple Boot Flag at 0x%x set to 0x%x\n",
sbf_port, v);
|