On Wed, Sep 13, 2023 at 01:34:11PM -0700, Randy Dunlap wrote:
>
>
> On 9/12/23 22:04, Stephen Rothwell wrote:
> > Hi all,
> >
> > Changes since 20230912:
> >
> > The bpf-next tree (I think) gained a boot time warning due to a semantic
> > interaction with changes in the bpf tree.
> >
> > The drm-misc tree gained a conflict against Linus' tree.
> >
> > Non-merge commits (relative to Linus' tree): 4427
> > 1907 files changed, 354449 insertions(+), 27039 deletions(-)
> >
> > ----------------------------------------------------------------------------
>
> on x86_64:
>
> drivers/media/common/siano/smscoreapi.o: warning: objtool: .text.unlikely: unexpected end of section
>
> Full randconfig file is attached.
Objtool is correct:
Disassembly of section .text.unlikely:
0000000000000000 <smscore_set_device_mode.cold>:
0: 48 83 05 00 00 00 00 01 addq $0x1,0x0(%rip) # 8 <__UNIQUE_ID___addressable_smscore_unregister_client433> 3: R_X86_64_PC32 .bss+0xa03
It's not really a functional bug, it's just gcov somehow keeping GCC
from finishing an optimization.
In smscore_load_firmware_from_file(), which gets inlined by
smscore_set_device_mode(), GCC is smart enough to know that
'coredev->device_flags & SMS_DEVICE_FAMILY2'
is always true, so it half-optimizes out the ':' condition:
rc = (coredev->device_flags & SMS_DEVICE_FAMILY2) ?
smscore_load_firmware_family2(coredev, fw_buf, fw_buf_size)
: loadfirmware_handler(coredev->context, fw_buf,
fw_buf_size);
Though it actually still keeps the branch. It goes to
smscore_set_device_mode.cold so it can set the GCOV "branch taken" bit
for the !SMS_DEVICE_FAMILY2 case. But then it just falls off the edge
off .text.unlikely.
Peter, any opinions how to handle this?
We could just make smscore_load_firmware_from_file() noinline.
Or we could hard-code the fact that smscore_load_firmware_from_file() is
only called in the SMS_DEVICE_FAMILY2 case, like:
diff --git a/drivers/media/common/siano/smscoreapi.c b/drivers/media/common/siano/smscoreapi.c
index 7d4bc2733f2b..58d951903e93 100644
--- a/drivers/media/common/siano/smscoreapi.c
+++ b/drivers/media/common/siano/smscoreapi.c
@@ -1127,19 +1127,19 @@ static char *smscore_get_fw_filename(struct smscore_device_t *coredev,
* @param coredev pointer to a coredev object returned by
* smscore_register_device
* @param filename null-terminated string specifies firmware file name
- * @param loadfirmware_handler device handler that loads firmware
*
* return: 0 on success, <0 on error.
*/
static int smscore_load_firmware_from_file(struct smscore_device_t *coredev,
- int mode,
- loadfirmware_t loadfirmware_handler)
+ int mode)
{
int rc = -ENOENT;
u8 *fw_buf;
u32 fw_buf_size;
const struct firmware *fw;
+ BUG_ON(coredev->device_flags != SMS_DEVICE_FAMILY2);
+
char *fw_filename = smscore_get_fw_filename(coredev, mode);
if (!fw_filename) {
pr_err("mode %d not supported on this device\n", mode);
@@ -1147,10 +1147,6 @@ static int smscore_load_firmware_from_file(struct smscore_device_t *coredev,
}
pr_debug("Firmware name: %s\n", fw_filename);
- if (!loadfirmware_handler &&
- !(coredev->device_flags & SMS_DEVICE_FAMILY2))
- return -EINVAL;
-
rc = request_firmware(&fw, fw_filename, coredev->device);
if (rc < 0) {
pr_err("failed to open firmware file '%s'\n", fw_filename);
@@ -1166,10 +1162,7 @@ static int smscore_load_firmware_from_file(struct smscore_device_t *coredev,
memcpy(fw_buf, fw->data, fw->size);
fw_buf_size = fw->size;
- rc = (coredev->device_flags & SMS_DEVICE_FAMILY2) ?
- smscore_load_firmware_family2(coredev, fw_buf, fw_buf_size)
- : loadfirmware_handler(coredev->context, fw_buf,
- fw_buf_size);
+ rc = smscore_load_firmware_family2(coredev, fw_buf, fw_buf_size);
}
kfree(fw_buf);
@@ -1353,8 +1346,7 @@ int smscore_set_device_mode(struct smscore_device_t *coredev, int mode)
}
if (!(coredev->modes_supported & (1 << mode))) {
- rc = smscore_load_firmware_from_file(coredev,
- mode, NULL);
+ rc = smscore_load_firmware_from_file(coredev, mode);
if (rc >= 0)
pr_debug("firmware download success\n");
} else {
