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Thu, 24 Jul 2025 02:24:39 -0700 (PDT) From: Bartosz Golaszewski Date: Thu, 24 Jul 2025 11:24:29 +0200 Subject: [PATCH v3 01/15] lib: provide kmemdup_const() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250724-pinctrl-gpio-pinfuncs-v3-1-af4db9302de4@linaro.org> References: <20250724-pinctrl-gpio-pinfuncs-v3-0-af4db9302de4@linaro.org> In-Reply-To: <20250724-pinctrl-gpio-pinfuncs-v3-0-af4db9302de4@linaro.org> To: Linus Walleij , Bjorn Andersson , Konrad Dybcio , Alexey Klimov , Lorenzo Bianconi , Sean Wang , Matthias Brugger , AngeloGioacchino Del Regno , Paul Cercueil , Kees Cook , Andy Shevchenko , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Dong Aisheng , Fabio Estevam , Shawn Guo , Jacky Bai , Pengutronix Kernel Team , NXP S32 Linux Team , Sascha Hauer , Tony Lindgren , Haojian Zhuang , Geert Uytterhoeven Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, linux-hardening@vger.kernel.org, linux-mm@kvack.org, imx@lists.linux.dev, linux-omap@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Bartosz Golaszewski X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=2062; i=bartosz.golaszewski@linaro.org; h=from:subject:message-id; bh=4C1RHZTMKgGSo3gXRAvPeC6y45wc3aHImSFGh2Fz1QE=; b=owEBbQKS/ZANAwAKARGnLqAUcddyAcsmYgBogfvRcDL9XPXeHv8dyMY2ypjsvbwhNFFTJNmoy 2AX+ZslnGaJAjMEAAEKAB0WIQQWnetsC8PEYBPSx58Rpy6gFHHXcgUCaIH70QAKCRARpy6gFHHX ch0XD/9I+1OijkQL+cye+ZruBlaR1Ib2UfMF0QEOwEw0hfteX9fTl34LlB1334pIq4xxhDMyq4m FZH5qMf22U1fVmLVGDs7Py/y1aFeIly97+9z4U2zlOSQ6KH68lmB8I8pmA79F94Ls0nxwl9MXi9 A2WDTXvSoAA2nloXBT8D/2nv/HDVzSpY55mNCZn0QeI+lQwBhC02oOwDN3xg+aXfkSCzERHNLUX 6ccd3tZpTYjYcyaEzdS3Pr8xvrq/CKlcGx/7UWQO0XPKWcYr7NDzBhcuZ/Xnciwnmf+4bHDTfsj N+QXyPhCYpNecz+o9HYMzcZ49hkbaDDcHRzqJ1QAqMopPXRH2Y+uuN5IlTCvLCP0CxYJrSNK1Ir +t/tUQDIsNKH0oe60hktWfTdSPocCQ+A/e6joTSg7q7rwlh3PeajuYoz9tdr1v4bN3ZCgNI5NSy vb6WLdiiC8zV317SlA2fotQFgGqmCmNXHZ1MxIG8WdADW1csMF44skaq6TtMIu6B0JzqQVnJSCL 4ZhGqhYsud6CNJbYGa9BIZ+m3Kq6EysSbLmBPCEpH0cgs5Pui2X2PUIf6BHelaLNyHV0ckYn+Vx XUDG95SjgAiMT6Kq5zHT8VPY91QJwnLtOaPEAM/z3cF8qGMdmWR5fJT0BUlU6e7t3nqhfPtV96G w8wHIy7JPNlWP+w== X-Developer-Key: i=bartosz.golaszewski@linaro.org; a=openpgp; fpr=169DEB6C0BC3C46013D2C79F11A72EA01471D772 From: Bartosz Golaszewski Provide a function similar to strdup_const() but for copying blocks of memory that are likely to be placed in .rodata. Signed-off-by: Bartosz Golaszewski Acked-by: Lorenzo Stoakes --- include/linux/string.h | 1 + mm/util.c | 21 +++++++++++++++++++++ 2 files changed, 22 insertions(+) diff --git a/include/linux/string.h b/include/linux/string.h index fdd3442c6bcbd786e177b6e87358e1065a0ffafc..1a86d61de91204563e4179938c4= dfc77108e03aa 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -304,6 +304,7 @@ extern char *kstrndup(const char *s, size_t len, gfp_t = gfp); extern void *kmemdup_noprof(const void *src, size_t len, gfp_t gfp) __real= loc_size(2); #define kmemdup(...) alloc_hooks(kmemdup_noprof(__VA_ARGS__)) =20 +extern const void *kmemdup_const(const void *src, size_t len, gfp_t gfp); extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_si= ze(2); extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp); extern void *kmemdup_array(const void *src, size_t count, size_t element_s= ize, gfp_t gfp) diff --git a/mm/util.c b/mm/util.c index f814e6a59ab1d354b8cd04ebf3903626f6b23a6c..f4df9194b0c69c27ff06e6ba1d1= 137c559035470 100644 --- a/mm/util.c +++ b/mm/util.c @@ -142,6 +142,27 @@ void *kmemdup_noprof(const void *src, size_t len, gfp_= t gfp) } EXPORT_SYMBOL(kmemdup_noprof); =20 +/** + * kmemdup_const - conditionally duplicate a region of memory + * + * @src: memory region to duplicate + * @len: memory region length, + * @gfp: GFP mask to use + * + * Return: source address if it is in .rodata or the return value of kmemd= up() + * to which the function falls back otherwise. + * + * Note: the returned address must not be passed to kfree(), the caller mu= st + * use kfree_const() instead. + */ +const void *kmemdup_const(const void *src, size_t len, gfp_t gfp) +{ + if (is_kernel_rodata((unsigned long)src)) + return src; + + return kmemdup(src, len, gfp); +} + /** * kmemdup_array - duplicate a given array. * --=20 2.48.1