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Wed, 29 Nov 2023 03:17:54 -0800 (PST) Date: Wed, 29 Nov 2023 12:16:13 +0100 In-Reply-To: <20231129111555.3594833-43-ardb@google.com> Mime-Version: 1.0 References: <20231129111555.3594833-43-ardb@google.com> X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 X-Developer-Signature: v=1; a=openpgp-sha256; l=919; i=ardb@kernel.org; h=from:subject; bh=a8dxnbCVuIOcCgztU0s2Sx4pxOy3Vvr1K6j+DaQBlrs=; b=owGbwMvMwCFmkMcZplerG8N4Wi2JITVdtv5feVLau7oitV+Fe3lZ5L5xczKv4q+yjHCUCY27N r+oSbijlIVBjINBVkyRRWD233c7T0+UqnWeJQszh5UJZAgDF6cATKR2GiPDtRt1WpZ62qpBHmx7 +1s5Jhxsaj31fxf/rga9xTGCMxd9YWRolO+P/Tx7t0hRaPDHrS+Xzm6fePzfomNZt+dvL45Q7pn LBgA= X-Mailer: git-send-email 2.43.0.rc1.413.gea7ed67945-goog Message-ID: <20231129111555.3594833-60-ardb@google.com> Subject: [PATCH v6 17/41] arm64: idreg-override: avoid strlen() to check for empty strings From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org Cc: Ard Biesheuvel , Catalin Marinas , Will Deacon , Marc Zyngier , Mark Rutland , Ryan Roberts , Anshuman Khandual , Kees Cook X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231129_031756_317179_A54617E8 X-CRM114-Status: GOOD ( 14.08 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Ard Biesheuvel strlen() is a costly way to decide whether a string is empty, as in that case, the first character will be NUL so we can check for that directly. Signed-off-by: Ard Biesheuvel --- arch/arm64/kernel/idreg-override.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c index 1eca93446345..8b22ca523186 100644 --- a/arch/arm64/kernel/idreg-override.c +++ b/arch/arm64/kernel/idreg-override.c @@ -232,7 +232,7 @@ static void __init match_options(const char *cmdline) override = prel64_pointer(reg->override); - for (f = 0; strlen(reg->fields[f].name); f++) { + for (f = 0; reg->fields[f].name[0] != '\0'; f++) { u64 shift = reg->fields[f].shift; u64 width = reg->fields[f].width ?: 4; u64 mask = GENMASK_ULL(shift + width - 1, shift); -- 2.43.0.rc1.413.gea7ed67945-goog _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel