From 18281b257801947bb0b23c02df87d6acd92c6910 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Mon, 22 Jan 2024 17:37:35 +0000 Subject: [PATCH] bswap.h: Fix const_le64() macro MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The const_le64() macro introduced in commit 845d80a8c7b187 turns out to have a bug which means that on big-endian systems the compiler complains if the argument isn't already a 64-bit type. This hasn't caused a problem yet, because there are no in-tree uses, but it means it's not possible for anybody to add one without it failing CI. This example is from an attempted use of it with the argument '0', from the s390 CI runner's gcc: ../block/blklogwrites.c: In function ‘blk_log_writes_co_do_log’: ../include/qemu/bswap.h:148:36: error: left shift count >= width of type [-Werror=shift-count-overflow] 148 | ((((_x) & 0x00000000000000ffU) << 56) | \ | ^~ ../block/blklogwrites.c:409:27: note: in expansion of macro ‘const_le64’ 409 | .nr_entries = const_le64(0), | ^~~~~~~~~~ ../include/qemu/bswap.h:149:36: error: left shift count >= width of type [-Werror=shift-count-overflow] 149 | (((_x) & 0x000000000000ff00U) << 40) | \ | ^~ ../block/blklogwrites.c:409:27: note: in expansion of macro ‘const_le64’ 409 | .nr_entries = const_le64(0), | ^~~~~~~~~~ cc1: all warnings being treated as errors Fix this by making all the constants in the macro have the ULL suffix. This will cause them all to be 64-bit integers, which means the result of the logical & will also be an unsigned 64-bit type, even if the input to the macro is a smaller type, and so the shifts will be in range. Fixes: 845d80a8c7b187 ("qemu/bswap: Add const_le64()") Signed-off-by: Peter Maydell Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Thomas Huth Reviewed-by: Kevin Wolf Reviewed-by: Ira Weiny Message-id: 20240122173735.472951-1-peter.maydell@linaro.org --- include/qemu/bswap.h | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/include/qemu/bswap.h b/include/qemu/bswap.h index 933a66ee87..bd67468e5e 100644 --- a/include/qemu/bswap.h +++ b/include/qemu/bswap.h @@ -145,14 +145,14 @@ CPU_CONVERT(le, 64, uint64_t) */ #if HOST_BIG_ENDIAN # define const_le64(_x) \ - ((((_x) & 0x00000000000000ffU) << 56) | \ - (((_x) & 0x000000000000ff00U) << 40) | \ - (((_x) & 0x0000000000ff0000U) << 24) | \ - (((_x) & 0x00000000ff000000U) << 8) | \ - (((_x) & 0x000000ff00000000U) >> 8) | \ - (((_x) & 0x0000ff0000000000U) >> 24) | \ - (((_x) & 0x00ff000000000000U) >> 40) | \ - (((_x) & 0xff00000000000000U) >> 56)) + ((((_x) & 0x00000000000000ffULL) << 56) | \ + (((_x) & 0x000000000000ff00ULL) << 40) | \ + (((_x) & 0x0000000000ff0000ULL) << 24) | \ + (((_x) & 0x00000000ff000000ULL) << 8) | \ + (((_x) & 0x000000ff00000000ULL) >> 8) | \ + (((_x) & 0x0000ff0000000000ULL) >> 24) | \ + (((_x) & 0x00ff000000000000ULL) >> 40) | \ + (((_x) & 0xff00000000000000ULL) >> 56)) # define const_le32(_x) \ ((((_x) & 0x000000ffU) << 24) | \ (((_x) & 0x0000ff00U) << 8) | \