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Fri, 31 Jul 2020 09:34:22 +0100 From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 0/2] arm64: Allow erratum 1418040 for late CPUs Date: Fri, 31 Jul 2020 09:33:56 +0100 Message-Id: <20200731083358.50058-1-maz@kernel.org> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: linux-arm-kernel@lists.infradead.org, saiprakash.ranjan@codeaurora.org, will@kernel.org, catalin.marinas@arm.com, suzuki.poulose@arm.com, swboyd@chromium.org, dianders@google.com, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200731_043425_109786_081FCEBD X-CRM114-Status: GOOD ( 13.65 ) X-Spam-Score: -5.2 (-----) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-5.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at https://www.dnswl.org/, high trust [198.145.29.99 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.0 DKIMWL_WL_HIGH DKIMwl.org - Whitelisted High sender X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sai Prakash Ranjan , kernel-team@android.com, Suzuki K Poulose , Catalin Marinas , Stephen Boyd , dianders@google.com, Will Deacon Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Erratum 1418040 currently prevents a late CPU from booting if none of the early CPUs are affected by it. This is because the handling is implemented as alternatives, and we have already got rid of them by the time userspace onlines a new CPU. A solution to this is to move everything into C code, and rely on static keys instead. Once this is done, the feature can be allowed for late CPUs. Note that CPUs affected by 1418040 also tend to miss AArch32-EL1, meaning they cannot be used as late CPUs when KVM is enabled and that their sibblings have AArch32-EL1. * From v1: - Dropped check for kernel threads - Added comment describing the switching logic - Made the errata handling function __always_inline Marc Zyngier (2): arm64: Move handling of erratum 1418040 into C code arm64: Allow booting of late CPUs affected by erratum 1418040 arch/arm64/kernel/cpu_errata.c | 2 ++ arch/arm64/kernel/entry.S | 21 -------------------- arch/arm64/kernel/process.c | 35 ++++++++++++++++++++++++++++++++++ 3 files changed, 37 insertions(+), 21 deletions(-)