[PATCH] arm64: cpufeature: fix CPU features mismatch message

From: Dmitry Baryshkov
Date: Tue Nov 16 2021 - 16:59:29 EST


Fix cpp magic involved in ARM64_FTR_REG/ARM64_FTR_REG_OVERRIDE macros.
Currently ARM64_FTR_REG parameters are expanded early, resulting in
cryptic debug messages:

[ 0.071123] CPU features: SANITY CHECK: Unexpected variation in (((3) << 19) | ((0) << 16) | ((0) << 12) | ((7) << 8) | ((0) << 5)). Boot CPU: 0x00022200101022, CPU4: 0x00022200101122

Make ARM64_FTR_REG to be expanded before parameters, resulting in proper
debug log:

[ 0.071163] CPU features: SANITY CHECK: Unexpected variation in SYS_ID_AA64MMFR0_EL1. Boot CPU: 0x00022200101022, CPU4: 0x00022200101122

Fixes: 8f266a5d878a ("arm64: cpufeature: Add global feature override facility")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
---
arch/arm64/kernel/cpufeature.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 6ec7036ef7e1..72e3e3819eb4 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -573,15 +573,17 @@ static const struct arm64_ftr_bits ftr_raz[] = {
ARM64_FTR_END,
};

-#define ARM64_FTR_REG_OVERRIDE(id, table, ovr) { \
+#define __ARM64_FTR_REG(id, _name, table, ovr) { \
.sys_id = id, \
.reg = &(struct arm64_ftr_reg){ \
- .name = #id, \
+ .name = _name, \
.override = (ovr), \
.ftr_bits = &((table)[0]), \
}}

-#define ARM64_FTR_REG(id, table) ARM64_FTR_REG_OVERRIDE(id, table, &no_override)
+#define ARM64_FTR_REG_OVERRIDE(id, table, ovr) __ARM64_FTR_REG(id, #id, table, ovr)
+
+#define ARM64_FTR_REG(id, table) __ARM64_FTR_REG(id, #id, table, &no_override)

struct arm64_ftr_override __ro_after_init id_aa64mmfr1_override;
struct arm64_ftr_override __ro_after_init id_aa64pfr1_override;
--
2.33.0