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Subject[PATCH 2/2] arm64: capabilities: Group handling of features and errata workarounds
Date
We can now handle each capability entry independent of whether
it is a feature or an errata workaround. This patch consolidates
the handling of the capabilities, by grouping them, to streamline
the code flow.

Cc: Dave Martin <dave.martin@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
arch/arm64/kernel/cpufeature.c | 99 +++++++++++++++++++++---------------------
1 file changed, 50 insertions(+), 49 deletions(-)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index e1a56fa889a5..31d1e02ed5be 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -504,8 +504,7 @@ static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new)
}

extern const struct arm64_cpu_capabilities arm64_errata[];
-static void update_cpu_errata_workarounds(void);
-static void update_cpu_local_features(void);
+static void update_cpu_local_capabilities(void);

void __init init_cpu_features(struct cpuinfo_arm64 *info)
{
@@ -554,8 +553,7 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
* Run the errata work around checks on the boot CPU, once we have
* initialised the cpu feature infrastructure.
*/
- update_cpu_errata_workarounds();
- update_cpu_local_features();
+ update_cpu_local_capabilities();
}

static void update_cpu_ftr_reg(struct arm64_ftr_reg *reg, u64 new)
@@ -1223,8 +1221,8 @@ static bool __this_cpu_has_cap(const struct arm64_cpu_capabilities *cap_array,
return false;
}

-static void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
- u16 scope_mask, const char *info)
+static void __update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
+ u16 scope_mask, const char *info)
{
scope_mask &= ARM64_CPUCAP_SCOPE_MASK;
for (; caps->matches; caps++) {
@@ -1238,6 +1236,15 @@ static void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
}
}

+/* Detect all capabilities which match the given scope_mask */
+static void update_cpu_capabilities(u16 scope_mask)
+{
+ __update_cpu_capabilities(arm64_features, scope_mask,
+ "detected feature:");
+ __update_cpu_capabilities(arm64_errata, scope_mask,
+ "enabling work around for");
+}
+
static int __enable_cpu_capability(void *arg)
{
const struct arm64_cpu_capabilities *cap = arg;
@@ -1251,7 +1258,7 @@ static int __enable_cpu_capability(void *arg)
* CPUs
*/
static void __init
-enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps, u16 scope_mask)
+__enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps, u16 scope_mask)
{
scope_mask &= ARM64_CPUCAP_SCOPE_MASK;
for (; caps->matches; caps++) {
@@ -1330,6 +1337,13 @@ static bool __verify_local_cpu_caps(const struct arm64_cpu_capabilities *caps_li
return true;
}

+/* Verify this CPU against all the capabilities that match the scope */
+static bool verify_local_cpu_caps(u16 scope_mask)
+{
+ return __verify_local_cpu_caps(arm64_features, scope_mask) &&
+ __verify_local_cpu_caps(arm64_errata, scope_mask);
+}
+
/*
* Check for CPU features that are used in early boot
* based on the Boot CPU value.
@@ -1352,12 +1366,6 @@ verify_local_elf_hwcaps(const struct arm64_cpu_capabilities *caps)
}
}

-static void verify_local_cpu_features(void)
-{
- if (!__verify_local_cpu_caps(arm64_features, ARM64_CPUCAP_SCOPE_ALL))
- cpu_die_early();
-}
-
static void verify_sve_features(void)
{
u64 safe_zcr = read_sanitised_ftr_reg(SYS_ZCR_EL1);
@@ -1376,28 +1384,29 @@ static void verify_sve_features(void)
}

/*
- * The CPU Errata work arounds are detected and applied at boot time
- * and the related information is freed soon after. If the new CPU requires
- * an errata not detected at boot, fail this CPU.
+ * Check for all capablities within the scope of local CPU.
+ * This is run on all boot time activated CPUs.
*/
-static void verify_local_cpu_errata_workarounds(void)
+static void update_cpu_local_capabilities(void)
{
- if (!__verify_local_cpu_caps(arm64_errata, ARM64_CPUCAP_SCOPE_ALL))
- cpu_die_early();
+ update_cpu_capabilities(ARM64_CPUCAP_SCOPE_LOCAL_CPU);
}

-static void update_cpu_errata_workarounds(void)
+/*
+ * Check for all capablities with a system wide scope.
+ * This is run only once after all the boot CPUs are
+ * brought online.
+ */
+static void update_system_capabilities(void)
{
- update_cpu_capabilities(arm64_errata,
- ARM64_CPUCAP_SCOPE_LOCAL_CPU,
- "enabling workaround for");
+ update_cpu_capabilities(ARM64_CPUCAP_SCOPE_SYSTEM);
}

-static void update_cpu_local_features(void)
+/* Enable all the capabilities matching the given scope mask */
+static void enable_cpu_capabilities(u16 scope_mask)
{
- update_cpu_capabilities(arm64_features,
- ARM64_CPUCAP_SCOPE_LOCAL_CPU,
- "detected feature:");
+ __enable_cpu_capabilities(arm64_errata, scope_mask);
+ __enable_cpu_capabilities(arm64_features, scope_mask);
}

/*
@@ -1410,8 +1419,8 @@ static void update_cpu_local_features(void)
*/
static void verify_local_cpu_capabilities(void)
{
- verify_local_cpu_errata_workarounds();
- verify_local_cpu_features();
+ if (!verify_local_cpu_caps(ARM64_CPUCAP_SCOPE_ALL))
+ cpu_die_early();
verify_local_elf_hwcaps(arm64_elf_hwcaps);

if (system_supports_32bit_el0())
@@ -1438,28 +1447,21 @@ void check_local_cpu_capabilities(void)
* Otherwise, this CPU should verify that it has all the system
* advertised capabilities.
*/
- if (!sys_caps_initialised) {
- update_cpu_errata_workarounds();
- update_cpu_local_features();
- } else {
+ if (!sys_caps_initialised)
+ update_cpu_local_capabilities();
+ else
verify_local_cpu_capabilities();
- }
}

-static void __init setup_feature_capabilities(void)
+static void __init setup_system_capabilities(void)
{
- update_cpu_capabilities(arm64_features,
- ARM64_CPUCAP_SCOPE_SYSTEM,
- "detected feature:");
- enable_cpu_capabilities(arm64_features, ARM64_CPUCAP_SCOPE_ALL);
-}
-
-static void __init setup_errata_workarounds(void)
-{
- update_cpu_capabilities(arm64_errata,
- ARM64_CPUCAP_SCOPE_SYSTEM,
- "enabling workaround for");
- enable_cpu_capabilities(arm64_errata, ARM64_CPUCAP_SCOPE_ALL);
+ /*
+ * We have finalised the system wide safe feature registers,
+ * finalise the capabilities that depend on it.
+ */
+ update_system_capabilities();
+ /* Enable all the available capabilities */
+ enable_cpu_capabilities(ARM64_CPUCAP_SCOPE_ALL);
}

DEFINE_STATIC_KEY_FALSE(arm64_const_caps_ready);
@@ -1484,8 +1486,7 @@ void __init setup_cpu_features(void)
int cls;

/* Finalise the CPU capabilities */
- setup_feature_capabilities();
- setup_errata_workarounds();
+ setup_system_capabilities();
mark_const_caps_ready();
setup_elf_hwcaps(arm64_elf_hwcaps);

--
2.14.3
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