On Thu, 13 Feb 2025 16:12:48 +0000
Steven Price <steven.price@xxxxxxx> wrote:
> Assigning a string to an array which is too small to include the NUL
> byte at the end causes a warning on some compilers. But this function
> also has some other oddities like the 'header' array which is only ever
> used within sizeof().
>
> Tidy up the function by removing the 'header' array, allow the NUL byte
> to be present in git_sha_header, and calculate the length directly from
> git_sha_header.
>
> Reported-by: Will Deacon <will@xxxxxxxxxx>
> Fixes: 9d443deb0441 ("drm/panthor: Display FW version information")
> Signed-off-by: Steven Price <steven.price@xxxxxxx>
Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
> ---
> Note that there should be no functional change from this patch.
> ---
> drivers/gpu/drm/panthor/panthor_fw.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_fw.c b/drivers/gpu/drm/panthor/panthor_fw.c
> index 4a9c4afa9ad7..645fc6d2e63b 100644
> --- a/drivers/gpu/drm/panthor/panthor_fw.c
> +++ b/drivers/gpu/drm/panthor/panthor_fw.c
> @@ -636,8 +636,8 @@ static int panthor_fw_read_build_info(struct panthor_device *ptdev,
> u32 ehdr)
> {
> struct panthor_fw_build_info_hdr hdr;
> - char header[9];
> - const char git_sha_header[sizeof(header)] = "git_sha: ";
> + const char git_sha_header[] = "git_sha: ";
> + const int header_len = sizeof(git_sha_header) - 1;
> int ret;
>
> ret = panthor_fw_binary_iter_read(ptdev, iter, &hdr, sizeof(hdr));
> @@ -651,8 +651,7 @@ static int panthor_fw_read_build_info(struct panthor_device *ptdev,
> return 0;
> }
>
> - if (memcmp(git_sha_header, fw->data + hdr.meta_start,
> - sizeof(git_sha_header))) {
> + if (memcmp(git_sha_header, fw->data + hdr.meta_start, header_len)) {
> /* Not the expected header, this isn't metadata we understand */
> return 0;
> }
> @@ -665,7 +664,7 @@ static int panthor_fw_read_build_info(struct panthor_device *ptdev,
> }
>
> drm_info(&ptdev->base, "Firmware git sha: %s\n",
> - fw->data + hdr.meta_start + sizeof(git_sha_header));
> + fw->data + hdr.meta_start + header_len);
>
> return 0;
> }
