In commit 892f7237b3ff ("arm64: Delay initialisation of
cpuinfo_arm64::reg_{zcr,smcr}") we moved access to ZCR, SMCR and SMIDR
later in the boot process in order to ensure that we don't attempt to
interact with them if SVE or SME is disabled on the command line.
Unfortunately when initialising the boot CPU in init_cpu_features() we work
on a copy of the struct cpuinfo_arm64 for the boot CPU used only during
boot, not the percpu copy used by the sysfs code.
Fix this by moving the handling for SMIDR_EL1 for the boot CPU to
cpuinfo_store_boot_cpu() so it can operate on the percpu copy of the data.
This reduces the potential for error that could come from having both the
percpu and boot CPU copies in init_cpu_features().
This issue wasn't apparent when testing on emulated platforms that do not
report values in this ID register.
Fixes: 892f7237b3ff ("arm64: Delay initialisation of cpuinfo_arm64::reg_{zcr,smcr}")
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
arch/arm64/kernel/cpufeature.c | 6 ------
arch/arm64/kernel/cpuinfo.c | 11 +++++++++++
2 files changed, 11 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 6ce71f444ed84f9056196bb21bbfac61c9687e30..b88102fd2c20f77e25af6df513fda09a484e882e 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1167,12 +1167,6 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
id_aa64pfr1_sme(read_sanitised_ftr_reg(SYS_ID_AA64PFR1_EL1))) {
unsigned long cpacr = cpacr_save_enable_kernel_sme();
- /*
- * We mask out SMPS since even if the hardware
- * supports priorities the kernel does not at present
- * and we block access to them.
- */
- info->reg_smidr = read_cpuid(SMIDR_EL1) & ~SMIDR_EL1_SMPS;
vec_init_vq_map(ARM64_VEC_SME);
cpacr_restore(cpacr);
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index d79e88fccdfce427507e7a34c5959ce6309cbd12..b7d403da71e5a01ed3943eb37e7a00af238771a2 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -499,4 +499,15 @@ void __init cpuinfo_store_boot_cpu(void)
boot_cpu_data = *info;
init_cpu_features(&boot_cpu_data);
+
+ /* SMIDR_EL1 needs to be stored in the percpu data for sysfs */
+ if (IS_ENABLED(CONFIG_ARM64_SME) &&
+ id_aa64pfr1_sme(read_sanitised_ftr_reg(SYS_ID_AA64PFR1_EL1))) {
+ /*
+ * We mask out SMPS since even if the hardware
+ * supports priorities the kernel does not at present
+ * and we block access to them.
+ */
+ info->reg_smidr = read_cpuid(SMIDR_EL1) & ~SMIDR_EL1_SMPS;
+ }
}
---
base-commit: fac04efc5c793dccbd07e2d59af9f90b7fc0dca4
change-id: 20241213-arm64-fix-boot-cpu-smidr-386b8db292b2
Best regards,
--
Mark Brown <broonie@xxxxxxxxxx>
