[PATCH v3 1/5] arm64: cpufeature: Add scope for capability check
From: Suzuki K Poulose
Date: Thu Apr 21 2016 - 10:56:54 EST
Add scope parameter to the arm64_cpu_capabilities::matches(), so that
this can be reused for checking the capability on a given CPU vs the
system wide. The system uses the default scope associated with the
capability for initialising the CPU_HWCAPs and ELF_HWCAPs.
Cc: James Morse <james.morse@xxxxxxx>
Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
Cc: Andre Przywara <andre.przywara@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
---
Changes since V2:
- Rename SCOPE_CPU => SCOPE_LOCAL_CPU
- Add check for preemptible() for SCOPE_LOCAL_CPU checks
Changes since V1:
- Add a default scope for capabilities used by the system checks.
- Add WARN_ON() for !SCOPE_CPU for midr checks
---
arch/arm64/include/asm/cpufeature.h | 9 ++++++-
arch/arm64/kernel/cpu_errata.c | 4 ++-
arch/arm64/kernel/cpufeature.c | 47 ++++++++++++++++++++++-------------
3 files changed, 41 insertions(+), 19 deletions(-)
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index ca8fb4b..e501e4a 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -78,10 +78,17 @@ struct arm64_ftr_reg {
struct arm64_ftr_bits *ftr_bits;
};
+/* scope of capability check */
+enum {
+ SCOPE_SYSTEM,
+ SCOPE_LOCAL_CPU,
+};
+
struct arm64_cpu_capabilities {
const char *desc;
u16 capability;
- bool (*matches)(const struct arm64_cpu_capabilities *);
+ int def_scope; /* default scope */
+ bool (*matches)(const struct arm64_cpu_capabilities *caps, int scope);
void (*enable)(void *); /* Called on all active CPUs */
union {
struct { /* To be used for erratum handling only */
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 06afd04..2fdecd7 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -22,14 +22,16 @@
#include <asm/cpufeature.h>
static bool __maybe_unused
-is_affected_midr_range(const struct arm64_cpu_capabilities *entry)
+is_affected_midr_range(const struct arm64_cpu_capabilities *entry, int scope)
{
+ WARN_ON(scope != SCOPE_LOCAL_CPU || preemptible());
return MIDR_IS_CPU_MODEL_RANGE(read_cpuid_id(), entry->midr_model,
entry->midr_range_min,
entry->midr_range_max);
}
#define MIDR_RANGE(model, min, max) \
+ .def_scope = SCOPE_LOCAL_CPU, \
.matches = is_affected_midr_range, \
.midr_model = model, \
.midr_range_min = min, \
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 8c46621..e153489 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -71,7 +71,9 @@ DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
/* meta feature for alternatives */
static bool __maybe_unused
-cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry);
+cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused);
+
+static u64 __raw_read_system_reg(u32 sys_id);
static struct arm64_ftr_bits ftr_id_aa64isar0[] = {
ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 32, 32, 0),
@@ -633,19 +635,24 @@ feature_matches(u64 reg, const struct arm64_cpu_capabilities *entry)
}
static bool
-has_cpuid_feature(const struct arm64_cpu_capabilities *entry)
+has_cpuid_feature(const struct arm64_cpu_capabilities *entry, int scope)
{
u64 val;
- val = read_system_reg(entry->sys_reg);
+ WARN_ON(scope == SCOPE_LOCAL_CPU && preemptible());
+ if (scope == SCOPE_SYSTEM)
+ val = read_system_reg(entry->sys_reg);
+ else
+ val = __raw_read_system_reg(entry->sys_reg);
+
return feature_matches(val, entry);
}
-static bool has_useable_gicv3_cpuif(const struct arm64_cpu_capabilities *entry)
+static bool has_useable_gicv3_cpuif(const struct arm64_cpu_capabilities *entry, int scope)
{
bool has_sre;
- if (!has_cpuid_feature(entry))
+ if (!has_cpuid_feature(entry, scope))
return false;
has_sre = gic_enable_sre();
@@ -656,7 +663,7 @@ static bool has_useable_gicv3_cpuif(const struct arm64_cpu_capabilities *entry)
return has_sre;
}
-static bool has_no_hw_prefetch(const struct arm64_cpu_capabilities *entry)
+static bool has_no_hw_prefetch(const struct arm64_cpu_capabilities *entry, int __unused)
{
u32 midr = read_cpuid_id();
u32 rv_min, rv_max;
@@ -668,7 +675,7 @@ static bool has_no_hw_prefetch(const struct arm64_cpu_capabilities *entry)
return MIDR_IS_CPU_MODEL_RANGE(midr, MIDR_THUNDERX, rv_min, rv_max);
}
-static bool runs_at_el2(const struct arm64_cpu_capabilities *entry)
+static bool runs_at_el2(const struct arm64_cpu_capabilities *entry, int __unused)
{
return is_kernel_in_hyp_mode();
}
@@ -677,6 +684,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
{
.desc = "GIC system register CPU interface",
.capability = ARM64_HAS_SYSREG_GIC_CPUIF,
+ .def_scope = SCOPE_SYSTEM,
.matches = has_useable_gicv3_cpuif,
.sys_reg = SYS_ID_AA64PFR0_EL1,
.field_pos = ID_AA64PFR0_GIC_SHIFT,
@@ -687,6 +695,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
{
.desc = "Privileged Access Never",
.capability = ARM64_HAS_PAN,
+ .def_scope = SCOPE_SYSTEM,
.matches = has_cpuid_feature,
.sys_reg = SYS_ID_AA64MMFR1_EL1,
.field_pos = ID_AA64MMFR1_PAN_SHIFT,
@@ -699,6 +708,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
{
.desc = "LSE atomic instructions",
.capability = ARM64_HAS_LSE_ATOMICS,
+ .def_scope = SCOPE_SYSTEM,
.matches = has_cpuid_feature,
.sys_reg = SYS_ID_AA64ISAR0_EL1,
.field_pos = ID_AA64ISAR0_ATOMICS_SHIFT,
@@ -709,12 +719,14 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
{
.desc = "Software prefetching using PRFM",
.capability = ARM64_HAS_NO_HW_PREFETCH,
+ .def_scope = SCOPE_SYSTEM,
.matches = has_no_hw_prefetch,
},
#ifdef CONFIG_ARM64_UAO
{
.desc = "User Access Override",
.capability = ARM64_HAS_UAO,
+ .def_scope = SCOPE_SYSTEM,
.matches = has_cpuid_feature,
.sys_reg = SYS_ID_AA64MMFR2_EL1,
.field_pos = ID_AA64MMFR2_UAO_SHIFT,
@@ -725,17 +737,20 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
#ifdef CONFIG_ARM64_PAN
{
.capability = ARM64_ALT_PAN_NOT_UAO,
+ .def_scope = SCOPE_SYSTEM,
.matches = cpufeature_pan_not_uao,
},
#endif /* CONFIG_ARM64_PAN */
{
.desc = "Virtualization Host Extensions",
.capability = ARM64_HAS_VIRT_HOST_EXTN,
+ .def_scope = SCOPE_SYSTEM,
.matches = runs_at_el2,
},
{
.desc = "32-bit EL0 Support",
.capability = ARM64_HAS_32BIT_EL0,
+ .def_scope = SCOPE_SYSTEM,
.matches = has_cpuid_feature,
.sys_reg = SYS_ID_AA64PFR0_EL1,
.sign = FTR_UNSIGNED,
@@ -748,6 +763,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
#define HWCAP_CAP(reg, field, s, min_value, type, cap) \
{ \
.desc = #cap, \
+ .def_scope = SCOPE_SYSTEM, \
.matches = has_cpuid_feature, \
.sys_reg = reg, \
.field_pos = field, \
@@ -830,7 +846,7 @@ static bool cpus_have_elf_hwcap(const struct arm64_cpu_capabilities *cap)
static void __init setup_elf_hwcaps(const struct arm64_cpu_capabilities *hwcaps)
{
for (; hwcaps->matches; hwcaps++)
- if (hwcaps->matches(hwcaps))
+ if (hwcaps->matches(hwcaps, hwcaps->def_scope))
cap_set_elf_hwcap(hwcaps);
}
@@ -838,7 +854,7 @@ void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
const char *info)
{
for (; caps->matches; caps++) {
- if (!caps->matches(caps))
+ if (!caps->matches(caps, caps->def_scope))
continue;
if (!cpus_have_cap(caps->capability) && caps->desc)
@@ -929,28 +945,25 @@ static void
verify_local_elf_hwcaps(const struct arm64_cpu_capabilities *caps)
{
- for (; caps->matches; caps++) {
- if (!cpus_have_elf_hwcap(caps))
- continue;
- if (!feature_matches(__raw_read_system_reg(caps->sys_reg), caps)) {
+ for (; caps->matches; caps++)
+ if (cpus_have_elf_hwcap(caps) && !caps->matches(caps, SCOPE_LOCAL_CPU)) {
pr_crit("CPU%d: missing HWCAP: %s\n",
smp_processor_id(), caps->desc);
cpu_die_early();
}
- }
}
static void
verify_local_cpu_features(const struct arm64_cpu_capabilities *caps)
{
for (; caps->matches; caps++) {
- if (!cpus_have_cap(caps->capability) || !caps->sys_reg)
+ if (!cpus_have_cap(caps->capability))
continue;
/*
* If the new CPU misses an advertised feature, we cannot proceed
* further, park the cpu.
*/
- if (!feature_matches(__raw_read_system_reg(caps->sys_reg), caps)) {
+ if (!caps->matches(caps, SCOPE_LOCAL_CPU)) {
pr_crit("CPU%d: missing feature: %s\n",
smp_processor_id(), caps->desc);
cpu_die_early();
@@ -1021,7 +1034,7 @@ void __init setup_cpu_features(void)
}
static bool __maybe_unused
-cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry)
+cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused)
{
return (cpus_have_cap(ARM64_HAS_PAN) && !cpus_have_cap(ARM64_HAS_UAO));
}
--
1.7.9.5