| Message ID | 20250221095633.506678-1-sudeep.holla@arm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [1/2] firmware: arm_ffa: Explicitly cast return value from FFA_VERSION before comparison | expand |
diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c index 254aa57ddafd..a77bb205ff7d 100644 --- a/drivers/firmware/arm_ffa/driver.c +++ b/drivers/firmware/arm_ffa/driver.c @@ -144,7 +144,7 @@ static int ffa_version_check(u32 *version) .a0 = FFA_VERSION, .a1 = FFA_DRIVER_VERSION, }, &ver); - if (ver.a0 == FFA_RET_NOT_SUPPORTED) { + if ((s32)ver.a0 == FFA_RET_NOT_SUPPORTED) { pr_info("FFA_VERSION returned not supported\n"); return -EOPNOTSUPP; }
The return value ver.a0 is unsigned long type and FFA_RET_NOT_SUPPORTED is a negative value. Since the return value from the firmware can be just 32-bit even on 64-bit systems as FFA specification mentions it as int32 error code in w0 register, explicitly casting to s32 ensures correct sign interpretation when comparing against a signed error code FFA_RET_NOT_SUPPORTED. Without casting, comparison between unsigned long and a negative constant could lead to unintended results due to type promotions. Fixes: 3bbfe9871005 ("firmware: arm_ffa: Add initial Arm FFA driver support") Reported-by: Andrei Homescu <ahomescu@google.com> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> --- drivers/firmware/arm_ffa/driver.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)