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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id w64-20020a17090a6bc600b00219025945dcsm5429454pjj.19.2022.12.01.15.45.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Dec 2022 15:45:17 -0800 (PST) Date: Thu, 1 Dec 2022 15:45:16 -0800 From: Kees Cook To: Ard Biesheuvel Cc: linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, Sami Tolvanen Subject: Re: [PATCH] arm64: efi: Make runtime service wrapper more robust Message-ID: <202212011544.2AA7C8A5@keescook> References: <20221128094939.801232-1-ardb@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20221128094939.801232-1-ardb@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221201_154519_558486_1E82D190 X-CRM114-Status: GOOD ( 11.54 ) 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 On Mon, Nov 28, 2022 at 10:49:39AM +0100, Ard Biesheuvel wrote: > Prevent abuse of the runtime service wrapper code by avoiding restoring > the shadow call stack pointer from the ordinary stack, or the stack > pointer itself from a GPR. Also, given that the exception recovery > routine is never called in an ordinary way, it doesn't need BTI landing > pads so it can be SYM_CODE rather than SYM_FUNC. Does this mean x18 is now being spilled to the stack? (Do we already spill it in other places?) -- Kees Cook _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel