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Petersen" , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 10/12] sata: sx4: fix pdc20621_get_from_dimm() on 64-bit Date: Tue, 26 Mar 2024 15:53:37 +0100 Message-Id: <20240326145348.3318887-1-arnd@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240326144741.3094687-1-arnd@kernel.org> References: <20240326144741.3094687-1-arnd@kernel.org> Precedence: bulk X-Mailing-List: linux-kbuild@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Arnd Bergmann gcc warns about a memcpy() with overlapping pointers because of an incorrect size calculation: In file included from include/linux/string.h:369, from drivers/ata/sata_sx4.c:66: In function 'memcpy_fromio', inlined from 'pdc20621_get_from_dimm.constprop' at drivers/ata/sata_sx4.c:962:2: include/linux/fortify-string.h:97:33: error: '__builtin_memcpy' accessing 4294934464 bytes at offsets 0 and [16, 16400] overlaps 6442385281 bytes at offset -2147450817 [-Werror=restrict] 97 | #define __underlying_memcpy __builtin_memcpy | ^ include/linux/fortify-string.h:620:9: note: in expansion of macro '__underlying_memcpy' 620 | __underlying_##op(p, q, __fortify_size); \ | ^~~~~~~~~~~~~ include/linux/fortify-string.h:665:26: note: in expansion of macro '__fortify_memcpy_chk' 665 | #define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s, \ | ^~~~~~~~~~~~~~~~~~~~ include/asm-generic/io.h:1184:9: note: in expansion of macro 'memcpy' 1184 | memcpy(buffer, __io_virt(addr), size); | ^~~~~~ The problem here is the overflow of an unsigned 32-bit number to a negative that gets converted into a signed 'long', keeping a large positive number. Replace the complex calculation with a more readable min() variant that avoids the warning. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Arnd Bergmann --- drivers/ata/sata_sx4.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/ata/sata_sx4.c b/drivers/ata/sata_sx4.c index b51d7a9d0d90..a482741eb181 100644 --- a/drivers/ata/sata_sx4.c +++ b/drivers/ata/sata_sx4.c @@ -957,8 +957,7 @@ static void pdc20621_get_from_dimm(struct ata_host *host, void *psource, offset -= (idx * window_size); idx++; - dist = ((long) (window_size - (offset + size))) >= 0 ? size : - (long) (window_size - offset); + dist = min(size, window_size - offset); memcpy_fromio(psource, dimm_mmio + offset / 4, dist); psource += dist; @@ -1005,8 +1004,7 @@ static void pdc20621_put_to_dimm(struct ata_host *host, void *psource, readl(mmio + PDC_DIMM_WINDOW_CTLR); offset -= (idx * window_size); idx++; - dist = ((long)(s32)(window_size - (offset + size))) >= 0 ? size : - (long) (window_size - offset); + dist = min(size, window_size - offset); memcpy_toio(dimm_mmio + offset / 4, psource, dist); writel(0x01, mmio + PDC_GENERAL_CTLR); readl(mmio + PDC_GENERAL_CTLR); -- 2.39.2