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authorMark Rutland <mark.rutland@arm.com>2023-12-12 17:09:10 +0000
committerWill Deacon <will@kernel.org>2023-12-13 16:02:01 +0000
commiteb15d707c252c3fb56e3ea57a185976c67e5a07f (patch)
tree7e201f6332d5c11452e34e23c054544d18a50644
parent63a2d92e1461396cd83742cbaf20af240b7a94e9 (diff)
arm64: Align boot cpucap handling with system cpucap handling
Currently the detection+enablement of boot cpucaps is separate from the patching of boot cpucap alternatives, which means there's a period where cpus_have_cap($CAP) and alternative_has_cap($CAP) may be mismatched. It would be preferable to manage the boot cpucaps in the same way as the system cpucaps, both for clarity and to minimize the risk of accidental usage of code relying upon an alternative which has not yet been patched. This patch aligns the handling of boot cpucaps with the handling of system cpucaps: * The existing setup_boot_cpu_capabilities() function is moved to be closer to the setup_system_capabilities() and setup_system_features() functions so that they're more clearly related and more likely to be updated together in future. * The patching of boot cpucap alternatives is moved into setup_boot_cpu_capabilities(), immediately after boot cpucaps are detected and enabled. * A new setup_boot_cpu_features() function is added to mirror setup_system_features(); this handles initialization of cpucap data structures and calls setup_boot_cpu_capabilities(). This makes init_cpu_features() a closer mirror to update_cpu_features(), and makes smp_prepare_boot_cpu() a closer mirror to smp_cpus_done(). Importantly, while these changes alter the structure of the code, they retain the existing order of calls to: init_cpu_features(); // prefix initializing feature regs init_cpucap_indirect_list(); detect_system_supports_pseudo_nmi(); update_cpu_capabilities(SCOPE_BOOT_CPU | SCOPE_LOCAL_CPU); enable_cpu_capabilities(SCOPE_BOOT_CPU); apply_boot_alternatives(); ... and hence there should be no functional change as a result of this patch; this is purely a structural cleanup. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20231212170910.3745497-3-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org>
-rw-r--r--arch/arm64/include/asm/cpufeature.h1
-rw-r--r--arch/arm64/kernel/cpufeature.c57
-rw-r--r--arch/arm64/kernel/smp.c9
3 files changed, 33 insertions, 34 deletions
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index f6d416fe49b0..2ea24c5cb900 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -617,6 +617,7 @@ static inline bool id_aa64pfr1_mte(u64 pfr1)
return val >= ID_AA64PFR1_EL1_MTE_MTE2;
}
+void __init setup_boot_cpu_features(void);
void __init setup_system_features(void);
void __init setup_user_features(void);
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 5f1320c38aa2..e976538c11ac 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1081,25 +1081,6 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
if (id_aa64pfr1_mte(info->reg_id_aa64pfr1))
init_cpu_ftr_reg(SYS_GMID_EL1, info->reg_gmid);
-
- /*
- * Initialize the indirect array of CPU capabilities pointers before we
- * handle the boot CPU below.
- */
- init_cpucap_indirect_list();
-
- /*
- * Detect broken pseudo-NMI. Must be called _before_ the call to
- * setup_boot_cpu_capabilities() since it interacts with
- * can_use_gic_priorities().
- */
- detect_system_supports_pseudo_nmi();
-
- /*
- * Detect and enable early CPU capabilities based on the boot CPU,
- * after we have initialised the CPU feature infrastructure.
- */
- setup_boot_cpu_capabilities();
}
static void update_cpu_ftr_reg(struct arm64_ftr_reg *reg, u64 new)
@@ -3255,14 +3236,6 @@ void check_local_cpu_capabilities(void)
verify_local_cpu_capabilities();
}
-static void __init setup_boot_cpu_capabilities(void)
-{
- /* Detect capabilities with either SCOPE_BOOT_CPU or SCOPE_LOCAL_CPU */
- update_cpu_capabilities(SCOPE_BOOT_CPU | SCOPE_LOCAL_CPU);
- /* Enable the SCOPE_BOOT_CPU capabilities alone right away */
- enable_cpu_capabilities(SCOPE_BOOT_CPU);
-}
-
bool this_cpu_has_cap(unsigned int n)
{
if (!WARN_ON(preemptible()) && n < ARM64_NCAPS) {
@@ -3318,6 +3291,36 @@ unsigned long cpu_get_elf_hwcap2(void)
return elf_hwcap[1];
}
+static void __init setup_boot_cpu_capabilities(void)
+{
+ /*
+ * The boot CPU's feature register values have been recorded. Detect
+ * boot cpucaps and local cpucaps for the boot CPU, then enable and
+ * patch alternatives for the available boot cpucaps.
+ */
+ update_cpu_capabilities(SCOPE_BOOT_CPU | SCOPE_LOCAL_CPU);
+ enable_cpu_capabilities(SCOPE_BOOT_CPU);
+ apply_boot_alternatives();
+}
+
+void __init setup_boot_cpu_features(void)
+{
+ /*
+ * Initialize the indirect array of CPU capabilities pointers before we
+ * handle the boot CPU.
+ */
+ init_cpucap_indirect_list();
+
+ /*
+ * Detect broken pseudo-NMI. Must be called _before_ the call to
+ * setup_boot_cpu_capabilities() since it interacts with
+ * can_use_gic_priorities().
+ */
+ detect_system_supports_pseudo_nmi();
+
+ setup_boot_cpu_capabilities();
+}
+
static void __init setup_system_capabilities(void)
{
/*
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 85384dc9a89d..4ced34f62dab 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -453,14 +453,9 @@ void __init smp_prepare_boot_cpu(void)
* freed shortly, so we must move over to the runtime per-cpu area.
*/
set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
- cpuinfo_store_boot_cpu();
- /*
- * We now know enough about the boot CPU to apply the
- * alternatives that cannot wait until interrupt handling
- * and/or scheduling is enabled.
- */
- apply_boot_alternatives();
+ cpuinfo_store_boot_cpu();
+ setup_boot_cpu_features();
/* Conditionally switch to GIC PMR for interrupt masking */
if (system_uses_irq_prio_masking())