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authorMartin Fuzzey <mfuzzey@parkeon.com>2016-01-13 23:36:26 -0500
committerWill Deacon <will.deacon@arm.com>2016-01-25 18:37:44 +0000
commit8d1a0ae724ad74ef7946a45e3b2d3e01f39df02b (patch)
tree95c4e633c5ef8ae16bd3233ecee9f5e1e2b66623
parent92e963f50fc74041b5e9e744c330dca48e04f08d (diff)
downloadop-kernel-dev-8d1a0ae724ad74ef7946a45e3b2d3e01f39df02b.zip
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ARM: perf: Set ARMv7 SDER SUNIDEN bit
ARMv7 counters other than the CPU cycle counter only work if the Secure Debug Enable Register (SDER) SUNIDEN bit is set. Since access to the SDER is only possible in secure state, it will only be done if the device tree property "secure-reg-access" is set. Without this: Performance counter stats for 'sleep 1': 14606094 cycles # 0.000 GHz 0 instructions # 0.00 insns per cycle After applying: Performance counter stats for 'sleep 1': 5843809 cycles 2566484 instructions # 0.44 insns per cycle 1.020144000 seconds time elapsed Some platforms (eg i.MX53) may also need additional platform specific setup. Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Martin Fuzzey <mfuzzey@parkeon.com> Signed-off-by: Pooya Keshavarzi <Pooya.Keshavarzi@de.bosch.com> Signed-off-by: George G. Davis <george_davis@mentor.com> [will: add warning if property is found on arm64] Signed-off-by: Will Deacon <will.deacon@arm.com>
-rw-r--r--Documentation/devicetree/bindings/arm/pmu.txt10
-rw-r--r--arch/arm/kernel/perf_event_v7.c13
-rw-r--r--drivers/perf/arm_pmu.c9
-rw-r--r--include/linux/perf/arm_pmu.h1
4 files changed, 32 insertions, 1 deletions
diff --git a/Documentation/devicetree/bindings/arm/pmu.txt b/Documentation/devicetree/bindings/arm/pmu.txt
index 5651883..b6056d3 100644
--- a/Documentation/devicetree/bindings/arm/pmu.txt
+++ b/Documentation/devicetree/bindings/arm/pmu.txt
@@ -46,6 +46,16 @@ Optional properties:
- qcom,no-pc-write : Indicates that this PMU doesn't support the 0xc and 0xd
events.
+- secure-reg-access : Indicates that the ARMv7 Secure Debug Enable Register
+ (SDER) is accessible. This will cause the driver to do
+ any setup required that is only possible in ARMv7 secure
+ state. If not present the ARMv7 SDER will not be touched,
+ which means the PMU may fail to operate unless external
+ code (bootloader or security monitor) has performed the
+ appropriate initialisation. Note that this property is
+ not valid for non-ARMv7 CPUs or ARMv7 CPUs booting Linux
+ in Non-secure state.
+
Example:
pmu {
diff --git a/arch/arm/kernel/perf_event_v7.c b/arch/arm/kernel/perf_event_v7.c
index 4152158..1506385 100644
--- a/arch/arm/kernel/perf_event_v7.c
+++ b/arch/arm/kernel/perf_event_v7.c
@@ -712,6 +712,11 @@ static const struct attribute_group *armv7_pmuv2_attr_groups[] = {
#define ARMV7_EXCLUDE_USER (1 << 30)
#define ARMV7_INCLUDE_HYP (1 << 27)
+/*
+ * Secure debug enable reg
+ */
+#define ARMV7_SDER_SUNIDEN BIT(1) /* Permit non-invasive debug */
+
static inline u32 armv7_pmnc_read(void)
{
u32 val;
@@ -1094,7 +1099,13 @@ static int armv7pmu_set_event_filter(struct hw_perf_event *event,
static void armv7pmu_reset(void *info)
{
struct arm_pmu *cpu_pmu = (struct arm_pmu *)info;
- u32 idx, nb_cnt = cpu_pmu->num_events;
+ u32 idx, nb_cnt = cpu_pmu->num_events, val;
+
+ if (cpu_pmu->secure_access) {
+ asm volatile("mrc p15, 0, %0, c1, c1, 1" : "=r" (val));
+ val |= ARMV7_SDER_SUNIDEN;
+ asm volatile("mcr p15, 0, %0, c1, c1, 1" : : "r" (val));
+ }
/* The counter and interrupt enable registers are unknown at reset. */
for (idx = ARMV7_IDX_CYCLE_COUNTER; idx < nb_cnt; ++idx) {
diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 166637f..eb5bee0 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -889,6 +889,15 @@ int arm_pmu_device_probe(struct platform_device *pdev,
if (node && (of_id = of_match_node(of_table, pdev->dev.of_node))) {
init_fn = of_id->data;
+ pmu->secure_access = of_property_read_bool(pdev->dev.of_node,
+ "secure-reg-access");
+
+ /* arm64 systems boot only as non-secure */
+ if (IS_ENABLED(CONFIG_ARM64) && pmu->secure_access) {
+ pr_warn("ignoring \"secure-reg-access\" property for arm64\n");
+ pmu->secure_access = false;
+ }
+
ret = of_pmu_irq_cfg(pmu);
if (!ret)
ret = init_fn(pmu);
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index 83b5e34..2d5eaaa 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -104,6 +104,7 @@ struct arm_pmu {
atomic_t active_events;
struct mutex reserve_mutex;
u64 max_period;
+ bool secure_access; /* 32-bit ARM only */
struct platform_device *plat_device;
struct pmu_hw_events __percpu *hw_events;
struct notifier_block hotplug_nb;
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