From 70492cfce2a4d41e87bf46989028a90f4bc6b38f Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Tue, 2 Sep 2025 18:20:53 +0100 Subject: [PATCH] firmware: smccc: Fix Arm SMCCC SOC_ID name call Commit 5f9c23abc477 ("firmware: smccc: Support optional Arm SMCCC SOC_ID name") introduced the SOC_ID name string call, which reports a human readable string describing the SoC, as returned by firmware. The SMCCC spec v1.6 describes this feature as AArch64 only, since we rely on 8 characters to be transmitted per register. Consequently the SMCCC call must use the AArch64 calling convention, which requires bit 30 of the FID to be set. The spec is a bit confusing here, since it mentions that in the parameter description ("2: SoC name (optionally implemented for SMC64 calls, ..."), but still prints the FID explicitly as 0x80000002. But as this FID is using the SMC32 calling convention (correct for the other two calls), it will not match what any SMCCC conformant firmware is expecting, so any call would return NOT_SUPPORTED. Add a 64-bit version of the ARCH_SOC_ID FID macro, and use that for the SoC name version of the call to fix the issue. Fixes: 5f9c23abc477 ("firmware: smccc: Support optional Arm SMCCC SOC_ID name") Signed-off-by: Andre Przywara Link: https://patch.msgid.link/20250902172053.304911-1-andre.przywara@arm.com Signed-off-by: Sudeep Holla --- drivers/firmware/smccc/soc_id.c | 2 +- include/linux/arm-smccc.h | 5 +++++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/smccc/soc_id.c b/drivers/firmware/smccc/soc_id.c index 2f7475e66b3ca..a909d5e6dee50 100644 --- a/drivers/firmware/smccc/soc_id.c +++ b/drivers/firmware/smccc/soc_id.c @@ -60,7 +60,7 @@ static char __init *smccc_soc_name_init(void) * to the ARM_SMCCC_ARCH_SOC_ID function. Fetch it if * available. */ - args.a0 = ARM_SMCCC_ARCH_SOC_ID; + args.a0 = ARM_SMCCC_ARCH_SOC_ID64; args.a1 = 2; /* SOC_ID name */ arm_smccc_1_2_invoke(&args, &res); diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h index 50b47eba7d015..976c5f8001ff2 100644 --- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h @@ -90,6 +90,11 @@ ARM_SMCCC_SMC_32, \ 0, 2) +#define ARM_SMCCC_ARCH_SOC_ID64 \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_64, \ + 0, 2) + #define ARM_SMCCC_ARCH_WORKAROUND_1 \ ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ ARM_SMCCC_SMC_32, \ -- 2.47.3