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Wed, 06 Dec 2023 13:27:27 -0800 (PST) References: <20231122-arm64-gcs-v7-0-201c483bd775@kernel.org> <20231122-arm64-gcs-v7-22-201c483bd775@kernel.org> User-agent: mu4e 1.10.8; emacs 29.1 From: Thiago Jung Bauermann To: Mark Brown Cc: Catalin Marinas , Will Deacon , Jonathan Corbet , Andrew Morton , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Arnd Bergmann , Oleg Nesterov , Eric Biederman , Kees Cook , Shuah Khan , "Rick P. Edgecombe" , Deepak Gupta , Ard Biesheuvel , Szabolcs Nagy , "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Florian Weimer , Christian Brauner , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH v7 22/39] arm64/gcs: Implement shadow stack prctl() interface In-reply-to: <20231122-arm64-gcs-v7-22-201c483bd775@kernel.org> Date: Wed, 06 Dec 2023 18:27:25 -0300 Message-ID: <87edfzhvia.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain X-Rspam-User: X-Stat-Signature: smnh349qrxwwhoaf5uaa4d6cfi9wa7jz X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: D951D180019 X-HE-Tag: 1701898048-119822 X-HE-Meta: U2FsdGVkX18UTTCkwZsqDqjyJMzWNz1/LRcQ1DX0146n0qNnqftAdtNnh19mQNXn8BlxIim0kcBYEjmGeSBQ6aAG83iATSWPsAhtlL5DXe6u6lje+eGzS4Yb5STZFXeLfhL57iOcVj4D8syqY8wHI9Hj8pT7+ZsCNWvi1p8KmmHhJQQSe/yRVj+miRwWOJ6qS3kcG5NtePT/DA9kJb63HOsDxuuKsW3LxeN6abFYnLGXhaEjZpEOR1M81bZ0Ty2f7KD9UvNi113WXQORSKyDdm1d/jSozyTqqe2mPtJQRBK2IxkZAsX4j/ZfXVDYhUfbfuLCBC6+wkoZEu0QfNQxShHy3t0Btvsd5mXfGoUa8I1IbWzeJI0vcho/uExw5EuxpFyAi37/BaLAysZU9zDLuib2SwtCpWltcQyHXkc2Ivul7hWgYlWflkrj569S6M0ELpjYWg0hZ+EkUI5ghrHGvEURWmyoO9bnF7bYvXFEmxWYNTT1yLHocaoMWjVkDNUhSRAxOrn7QEqVNlUZcPml5tly0y3UGZ/JmgPRo3ESO2EM+H8/A10ndCBEhlvQv3rU+uFgBsd8HPwjsljKAr9DZVo51krBWNwISLmAb5wCcAe3B80o2Mjkn9yvRB7GbAM4vm0ctzVRKSrNvGicIWb8AYsfUnqRA8xufVWJdY9Cq9RqwrjsC1OR7w6PatDQS7+nOMXtsXVwA3Q3SgQ6kjflRldDujFTsjYv48MY5Cj3nw8TAqmyvES5L+4wFuu9ApQZE7NZ0a04GkNSas+2hE99xD6J4hX6p6ObPIZGsvzdcz7YPc+/yQqUgVkC2u6S09vQHW3LZN+FVszPDosZHRrjrZalZdXqB4eXUlTvqgdtJopXidNMr0b8Awt7dOZUxGjYM3LNyoVPQ4Bk0hjep95AJeCoJM+SHvDbXMXOP+IPUdF4XO1cL9LmAzfnY/iB/Yblw8q93HelgDoVfWWXD92 lgi234AC tF3UP9Qy7k1O+l4JdOu8EXVVt4Fzjm86c2WXjwlwMhKx7iLsC5t82oWye58qww6aUtO+SV2MpPAvl5iW/qVNu75aEj/m5X1JNekzx1BLRXEj9B6DM0cnekI6lgVTH2KhN7oNpMYaPDhsnrDcszP2PEv8xGusUjxnhqk8Oafd3ocB/4e/SDLiy5G43PDrRHvx+GEqSbcPw3H7BLYaUW5vZYSCFX+OVWBDGQW6iSnZHp0ZvcT/BLG96WV/49QiSGxt03Sl62SxJ+RhFzomXwpjl2coY+atCefD4Mz02xvKA+stPGJmwpayhkiLCkbLVbEMkUoppuLrbZdvhkkCnIp+9D+GRcMS2H7b7qJ+3KPLse6M7+VJy1c/xRjP38GivQZAN3Uiq5uy0IVRYcC+QHBBorW/qPPe/OODk/Wyx0obBlKuak3T3PV9gmDqppgGbkTivTg501ndEIhow9pNCV6ehbrJwDg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Mark Brown writes: > Implement the architecture neutral prtctl() interface for setting the > shadow stack status, this supports setting and reading the current GCS > configuration for the current thread. > > Userspace can enable basic GCS functionality and additionally also > support for GCS pushes and arbatrary GCS stores. It is expected that s/arbatrary/arbitrary/ > this prctl() will be called very early in application startup, for > example by the dynamic linker, and not subsequently adjusted during > normal operation. Users should carefully note that after enabling GCS > for a thread GCS will become active with no call stack so it is not > normally possible to return from the function that invoked the prctl(). -- Thiago