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Mon, 27 Nov 2023 02:21:46 -0800 (PST) Date: Mon, 27 Nov 2023 11:21:42 +0100 Mime-Version: 1.0 X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 X-Developer-Signature: v=1; a=openpgp-sha256; l=1038; i=ardb@kernel.org; h=from:subject; bh=ZYgTKo98EjNEAb+Wx9pUwGsWdHA/KVSKQH3sRbnlAC0=; b=owGbwMvMwCFmkMcZplerG8N4Wi2JITUld9tXT5lFETwLDtsGrNY/LP1K9+xTi0+ZF5Yd6Ngft HeHoK1fRykLgxgHg6yYIovA7L/vdp6eKFXrPEsWZg4rE8gQBi5OAZhIcDgjw46nv8VLfk1fm2i8 fM++oFXeNxfu2LFqQcVsPsbEkqJPOywYGSaY9wkrrFj9sS1w+t7jE4T7H+rdtFdr/ejPPmNJDtP hOYwA X-Mailer: git-send-email 2.43.0.rc1.413.gea7ed67945-goog Message-ID: <20231127102141.2241123-2-ardb@google.com> Subject: [PATCH] arm64: Avoid enabling KPTI unnecessarily From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org Cc: catalin.marinas@arm.com, will@kernel.org, maz@kernel.org, mark.rutland@arm.com, Ard Biesheuvel X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231127_022149_478339_E9A94252 X-CRM114-Status: GOOD ( 11.61 ) 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 Commit 42c5a3b04bf6 refactored the KPTI init code in a way that results in the use of non-global kernel mappings even on systems that have no need for it, and even when KPTI has been disabled explicitly via the command line. Ensure that this only happens when we have decided (based on the detected CPU features) that KPTI should be enabled. Fixes: 42c5a3b04bf6 ("arm64: Split kpti_install_ng_mappings()") Signed-off-by: Ard Biesheuvel --- arch/arm64/kernel/cpufeature.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 646591c67e7a..4b1762b9c37c 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -3352,7 +3352,8 @@ void __init setup_system_features(void) */ enable_cpu_capabilities(SCOPE_ALL & ~SCOPE_BOOT_CPU); - kpti_install_ng_mappings(); + if (arm64_kernel_unmapped_at_el0()) + kpti_install_ng_mappings(); sve_setup(); sme_setup(); -- 2.39.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel