From 861f40fa0edfe38806a2a6e7201bfed821906d2d Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 27 Sep 2021 11:37:57 +0200 Subject: [PATCH] am65-cpsw: avoid null pointer arithmetic clang warns about arithmetic on NULL pointers: drivers/net/ethernet/ti/am65-cpsw-ethtool.c:71:2: error: performing pointer subtraction with a null pointer has undefined behavior [-Werror,-Wnull-pointer-subtraction] AM65_CPSW_REGDUMP_REC(AM65_CPSW_REGDUMP_MOD_NUSS, 0x0, 0x1c), ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/net/ethernet/ti/am65-cpsw-ethtool.c:64:29: note: expanded from macro 'AM65_CPSW_REGDUMP_REC' .hdr.len = (((u32 *)(end)) - ((u32 *)(start)) + 1) * sizeof(u32) * 2 + \ ^ ~~~~~~~~~~~~~~~~ The expression here is easily changed to a calculation based on integers that is no less readable. Signed-off-by: Arnd Bergmann Signed-off-by: David S. Miller --- drivers/net/ethernet/ti/am65-cpsw-ethtool.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/ti/am65-cpsw-ethtool.c b/drivers/net/ethernet/ti/am65-cpsw-ethtool.c index 6e4d4f9..b05de9b 100644 --- a/drivers/net/ethernet/ti/am65-cpsw-ethtool.c +++ b/drivers/net/ethernet/ti/am65-cpsw-ethtool.c @@ -61,7 +61,7 @@ struct am65_cpsw_regdump_item { #define AM65_CPSW_REGDUMP_REC(mod, start, end) { \ .hdr.module_id = (mod), \ - .hdr.len = (((u32 *)(end)) - ((u32 *)(start)) + 1) * sizeof(u32) * 2 + \ + .hdr.len = (end + 4 - start) * 2 + \ sizeof(struct am65_cpsw_regdump_hdr), \ .start_ofs = (start), \ .end_ofs = end, \ -- 2.7.4