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firmware: arm_ffa: Explicitly cast return value from FFA_VERSION before comparison

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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: 3bbfe98710 ("firmware: arm_ffa: Add initial Arm FFA driver support")
Reported-by: Andrei Homescu <ahomescu@google.com>
Message-Id: <20250221095633.506678-1-sudeep.holla@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
This commit is contained in:
Sudeep Holla 2025-02-21 09:56:31 +00:00
parent 9472fe20d3
commit cecf6a5041
1 changed files with 1 additions and 1 deletions
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2
drivers/firmware/arm_ffa/driver.c
View File

@ -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;
}