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Peter Anvin" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen Subject: [PATCH -tip] x86/bootflag: Micro-optimize sbf_write() Date: Wed, 26 Feb 2025 16:36:56 +0100 Message-ID: <20250226153709.6370-1-ubizjak@gmail.com> X-Mailer: git-send-email 2.42.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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" Signed-off-by: "H. Peter Anvin" Signed-off-by: Uros Bizjak Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen --- 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 4d89a2d80d0f..b935c3e42bfd 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; =20 if (sbf_port !=3D -1) { - v &=3D ~SBF_PARITY; if (!parity(v)) - v |=3D SBF_PARITY; + v ^=3D SBF_PARITY; =20 printk(KERN_INFO "Simple Boot Flag at 0x%x set to 0x%x\n", sbf_port, v); --=20 2.42.0