| Message ID | 20240305184513.400364-1-giulio.benetti@benettiengineering.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] mmc-utils: mmc_cmds: fix type-punned warning on &ext_csd[] casting | expand |
> When building with -Werror=strict-aliasing error is thrown: > > mmc_cmds.c: In function 'do_ffu': > mmc_cmds.c:2972:2: error: dereferencing type-punned pointer will break strict- > aliasing rules [-Werror=strict-aliasing] > sect_done = htole32(*((__u32 > *)&ext_csd[EXT_CSD_NUM_OF_FW_SEC_PROG_0])); > ^ > cc1: all warnings being treated as errors > > Let's fix type-punned breaking strict-aliasing by implementing local > per_byte_htole32(__u8 *) and use it for the 2 present occurences of > htole32(). Let's also change sect_done type to __u32 for consistency. > > Suggested-by: Avri Altman <Avri.Altman@wdc.com> > Fixes: a1b594ca735e ("mmc-utils: ffu: Simplify ext_csd bytes parsing") > Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com> Reviewed-by: Avri Altman <avri.altman@wdc.com> > --- > V1->V2: > * implement local per_byte_htole32() as suggested by Avril Altman > --- > mmc_cmds.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/mmc_cmds.c b/mmc_cmds.c > index ae7b876..936e0c5 100644 > --- a/mmc_cmds.c > +++ b/mmc_cmds.c > @@ -58,6 +58,11 @@ > #define WPTYPE_PWRON 2 > #define WPTYPE_PERM 3 > > +static inline __u32 per_byte_htole32(__u8 *arr) > +{ > + return arr[0] | arr[1] << 8 | arr[2] << 16 | arr[3] << 24; > +} > + > int read_extcsd(int fd, __u8 *ext_csd) > { > int ret = 0; > @@ -2807,7 +2812,7 @@ static void set_ffu_single_cmd(struct > mmc_ioc_multi_cmd *multi_cmd, > __u8 *ext_csd, unsigned int bytes, __u8 *buf, > off_t offset) > { > - __u32 arg = htole32(*((__u32 *)&ext_csd[EXT_CSD_FFU_ARG_0])); > + __u32 arg = per_byte_htole32(&ext_csd[EXT_CSD_FFU_ARG_0]); > > /* send block count */ > set_single_cmd(&multi_cmd->cmds[1], MMC_SET_BLOCK_COUNT, 0, 0, > @@ -2827,7 +2832,7 @@ static void set_ffu_single_cmd(struct > mmc_ioc_multi_cmd *multi_cmd, > int do_ffu(int nargs, char **argv) > { > int dev_fd, img_fd; > - int sect_done = 0, retry = 3, ret = -EINVAL; > + int retry = 3, ret = -EINVAL; > unsigned int sect_size; > __u8 ext_csd[512]; > __u8 *buf = NULL; > @@ -2835,6 +2840,7 @@ int do_ffu(int nargs, char **argv) > char *device; > struct mmc_ioc_multi_cmd *multi_cmd = NULL; > unsigned int default_chunk = MMC_IOC_MAX_BYTES; > + __u32 sect_done = 0; > > assert (nargs == 3 || nargs == 4); > > @@ -2968,7 +2974,7 @@ do_retry: > } > > /* Test if we need to restart the download */ > - sect_done = htole32(*((__u32 > *)&ext_csd[EXT_CSD_NUM_OF_FW_SEC_PROG_0])); > + sect_done = > per_byte_htole32(&ext_csd[EXT_CSD_NUM_OF_FW_SEC_PROG_0]); > /* By spec, host should re-start download from the first sector if sect_done > is 0 */ > if (sect_done == 0) { > if (retry--) { > -- > 2.34.1
On Tue, 5 Mar 2024 at 19:52, Giulio Benetti <giulio.benetti@benettiengineering.com> wrote: > > When building with -Werror=strict-aliasing error is thrown: > > mmc_cmds.c: In function 'do_ffu': > mmc_cmds.c:2972:2: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] > sect_done = htole32(*((__u32 *)&ext_csd[EXT_CSD_NUM_OF_FW_SEC_PROG_0])); > ^ > cc1: all warnings being treated as errors > > Let's fix type-punned breaking strict-aliasing by implementing local > per_byte_htole32(__u8 *) and use it for the 2 present occurences of > htole32(). Let's also change sect_done type to __u32 for consistency. > > Suggested-by: Avri Altman <Avri.Altman@wdc.com> > Fixes: a1b594ca735e ("mmc-utils: ffu: Simplify ext_csd bytes parsing") > Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com> Applied to git.kernel.org/pub/scm/utils/mmc/mmc-utils.git master, thanks! Kind regards Uffe > --- > V1->V2: > * implement local per_byte_htole32() as suggested by Avril Altman > --- > mmc_cmds.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/mmc_cmds.c b/mmc_cmds.c > index ae7b876..936e0c5 100644 > --- a/mmc_cmds.c > +++ b/mmc_cmds.c > @@ -58,6 +58,11 @@ > #define WPTYPE_PWRON 2 > #define WPTYPE_PERM 3 > > +static inline __u32 per_byte_htole32(__u8 *arr) > +{ > + return arr[0] | arr[1] << 8 | arr[2] << 16 | arr[3] << 24; > +} > + > int read_extcsd(int fd, __u8 *ext_csd) > { > int ret = 0; > @@ -2807,7 +2812,7 @@ static void set_ffu_single_cmd(struct mmc_ioc_multi_cmd *multi_cmd, > __u8 *ext_csd, unsigned int bytes, __u8 *buf, > off_t offset) > { > - __u32 arg = htole32(*((__u32 *)&ext_csd[EXT_CSD_FFU_ARG_0])); > + __u32 arg = per_byte_htole32(&ext_csd[EXT_CSD_FFU_ARG_0]); > > /* send block count */ > set_single_cmd(&multi_cmd->cmds[1], MMC_SET_BLOCK_COUNT, 0, 0, > @@ -2827,7 +2832,7 @@ static void set_ffu_single_cmd(struct mmc_ioc_multi_cmd *multi_cmd, > int do_ffu(int nargs, char **argv) > { > int dev_fd, img_fd; > - int sect_done = 0, retry = 3, ret = -EINVAL; > + int retry = 3, ret = -EINVAL; > unsigned int sect_size; > __u8 ext_csd[512]; > __u8 *buf = NULL; > @@ -2835,6 +2840,7 @@ int do_ffu(int nargs, char **argv) > char *device; > struct mmc_ioc_multi_cmd *multi_cmd = NULL; > unsigned int default_chunk = MMC_IOC_MAX_BYTES; > + __u32 sect_done = 0; > > assert (nargs == 3 || nargs == 4); > > @@ -2968,7 +2974,7 @@ do_retry: > } > > /* Test if we need to restart the download */ > - sect_done = htole32(*((__u32 *)&ext_csd[EXT_CSD_NUM_OF_FW_SEC_PROG_0])); > + sect_done = per_byte_htole32(&ext_csd[EXT_CSD_NUM_OF_FW_SEC_PROG_0]); > /* By spec, host should re-start download from the first sector if sect_done is 0 */ > if (sect_done == 0) { > if (retry--) { > -- > 2.34.1 > >
diff --git a/mmc_cmds.c b/mmc_cmds.c index ae7b876..936e0c5 100644 --- a/mmc_cmds.c +++ b/mmc_cmds.c @@ -58,6 +58,11 @@ #define WPTYPE_PWRON 2 #define WPTYPE_PERM 3 +static inline __u32 per_byte_htole32(__u8 *arr) +{ + return arr[0] | arr[1] << 8 | arr[2] << 16 | arr[3] << 24; +} + int read_extcsd(int fd, __u8 *ext_csd) { int ret = 0; @@ -2807,7 +2812,7 @@ static void set_ffu_single_cmd(struct mmc_ioc_multi_cmd *multi_cmd, __u8 *ext_csd, unsigned int bytes, __u8 *buf, off_t offset) { - __u32 arg = htole32(*((__u32 *)&ext_csd[EXT_CSD_FFU_ARG_0])); + __u32 arg = per_byte_htole32(&ext_csd[EXT_CSD_FFU_ARG_0]); /* send block count */ set_single_cmd(&multi_cmd->cmds[1], MMC_SET_BLOCK_COUNT, 0, 0, @@ -2827,7 +2832,7 @@ static void set_ffu_single_cmd(struct mmc_ioc_multi_cmd *multi_cmd, int do_ffu(int nargs, char **argv) { int dev_fd, img_fd; - int sect_done = 0, retry = 3, ret = -EINVAL; + int retry = 3, ret = -EINVAL; unsigned int sect_size; __u8 ext_csd[512]; __u8 *buf = NULL; @@ -2835,6 +2840,7 @@ int do_ffu(int nargs, char **argv) char *device; struct mmc_ioc_multi_cmd *multi_cmd = NULL; unsigned int default_chunk = MMC_IOC_MAX_BYTES; + __u32 sect_done = 0; assert (nargs == 3 || nargs == 4); @@ -2968,7 +2974,7 @@ do_retry: } /* Test if we need to restart the download */ - sect_done = htole32(*((__u32 *)&ext_csd[EXT_CSD_NUM_OF_FW_SEC_PROG_0])); + sect_done = per_byte_htole32(&ext_csd[EXT_CSD_NUM_OF_FW_SEC_PROG_0]); /* By spec, host should re-start download from the first sector if sect_done is 0 */ if (sect_done == 0) { if (retry--) {
When building with -Werror=strict-aliasing error is thrown: mmc_cmds.c: In function 'do_ffu': mmc_cmds.c:2972:2: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] sect_done = htole32(*((__u32 *)&ext_csd[EXT_CSD_NUM_OF_FW_SEC_PROG_0])); ^ cc1: all warnings being treated as errors Let's fix type-punned breaking strict-aliasing by implementing local per_byte_htole32(__u8 *) and use it for the 2 present occurences of htole32(). Let's also change sect_done type to __u32 for consistency. Suggested-by: Avri Altman <Avri.Altman@wdc.com> Fixes: a1b594ca735e ("mmc-utils: ffu: Simplify ext_csd bytes parsing") Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com> --- V1->V2: * implement local per_byte_htole32() as suggested by Avril Altman --- mmc_cmds.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)