From 571719f0d8eb0e3109f15d2cce31244a9a2d5e26 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= Date: Tue, 3 Apr 2012 18:01:03 -0700 Subject: [PATCH] ARM: etm: Add sysfs entry to enable return stack if supported MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Change-Id: Icb73d60324ad0ddfc3e8a450a28bb3d90c702788 Signed-off-by: Arve Hjønnevåg --- arch/arm/include/asm/hardware/coresight.h | 4 ++ arch/arm/kernel/etm.c | 51 ++++++++++++++++++++++- 2 files changed, 53 insertions(+), 2 deletions(-) diff --git a/arch/arm/include/asm/hardware/coresight.h b/arch/arm/include/asm/hardware/coresight.h index 727ba0f0d44b..dcf74d715f2b 100644 --- a/arch/arm/include/asm/hardware/coresight.h +++ b/arch/arm/include/asm/hardware/coresight.h @@ -20,12 +20,14 @@ #define TRACER_TRACE_DATA_BIT 3 #define TRACER_TIMESTAMP_BIT 4 #define TRACER_BRANCHOUTPUT_BIT 5 +#define TRACER_RETURN_STACK_BIT 6 #define TRACER_ACCESSED BIT(TRACER_ACCESSED_BIT) #define TRACER_RUNNING BIT(TRACER_RUNNING_BIT) #define TRACER_CYCLE_ACC BIT(TRACER_CYCLE_ACC_BIT) #define TRACER_TRACE_DATA BIT(TRACER_TRACE_DATA_BIT) #define TRACER_TIMESTAMP BIT(TRACER_TIMESTAMP_BIT) #define TRACER_BRANCHOUTPUT BIT(TRACER_BRANCHOUTPUT_BIT) +#define TRACER_RETURN_STACK BIT(TRACER_RETURN_STACK_BIT) #define TRACER_TIMEOUT 10000 @@ -62,6 +64,7 @@ #define ETMCTRL_BRANCH_OUTPUT (1 << 8) #define ETMCTRL_CYCLEACCURATE (1 << 12) #define ETMCTRL_TIMESTAMP_EN (1 << 28) +#define ETMCTRL_RETURN_STACK_EN (1 << 29) /* ETM configuration code register */ #define ETMR_CONFCODE (0x04) @@ -136,6 +139,7 @@ #define ETMIDR_VERSION_PFT_1_0 0x30 #define ETMR_CCE 0x1e8 +#define ETMCCER_RETURN_STACK_IMPLEMENTED BIT(23) #define ETMCCER_TIMESTAMPING_IMPLEMENTED BIT(22) #define ETMR_TRACEIDR 0x200 diff --git a/arch/arm/kernel/etm.c b/arch/arm/kernel/etm.c index ad1ee5790a0e..93d06ba0fb60 100644 --- a/arch/arm/kernel/etm.c +++ b/arch/arm/kernel/etm.c @@ -123,6 +123,9 @@ static int trace_start_etm(struct tracectx *t, int id) if (t->flags & TRACER_TIMESTAMP) v |= ETMCTRL_TIMESTAMP_EN; + if (t->flags & TRACER_RETURN_STACK) + v |= ETMCTRL_RETURN_STACK_EN; + etm_unlock(t, id); etm_writel(t, id, v, ETMR_CTRL); @@ -702,10 +705,13 @@ static ssize_t trace_branch_output_store(struct kobject *kobj, return -EINVAL; mutex_lock(&tracer.mutex); - if (branch_output) + if (branch_output) { tracer.flags |= TRACER_BRANCHOUTPUT; - else + /* Branch broadcasting is incompatible with the return stack */ + tracer.flags &= ~TRACER_RETURN_STACK; + } else { tracer.flags &= ~TRACER_BRANCHOUTPUT; + } mutex_unlock(&tracer.mutex); return n; @@ -715,6 +721,39 @@ static struct kobj_attribute trace_branch_output_attr = __ATTR(trace_branch_output, 0644, trace_branch_output_show, trace_branch_output_store); +static ssize_t trace_return_stack_show(struct kobject *kobj, + struct kobj_attribute *attr, + char *buf) +{ + return sprintf(buf, "%d\n", !!(tracer.flags & TRACER_RETURN_STACK)); +} + +static ssize_t trace_return_stack_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t n) +{ + unsigned int return_stack; + + if (sscanf(buf, "%u", &return_stack) != 1) + return -EINVAL; + + mutex_lock(&tracer.mutex); + if (return_stack) { + tracer.flags |= TRACER_RETURN_STACK; + /* Return stack is incompatible with branch broadcasting */ + tracer.flags &= ~TRACER_BRANCHOUTPUT; + } else { + tracer.flags &= ~TRACER_RETURN_STACK; + } + mutex_unlock(&tracer.mutex); + + return n; +} + +static struct kobj_attribute trace_return_stack_attr = + __ATTR(trace_return_stack, 0644, + trace_return_stack_show, trace_return_stack_store); + static ssize_t trace_timestamp_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) @@ -899,6 +938,14 @@ static int __devinit etm_probe(struct amba_device *dev, const struct amba_id *id dev_dbg(&dev->dev, "Failed to create trace_branch_output in sysfs\n"); + if (etmccer & ETMCCER_RETURN_STACK_IMPLEMENTED) { + ret = sysfs_create_file(&dev->dev.kobj, + &trace_return_stack_attr.attr); + if (ret) + dev_dbg(&dev->dev, + "Failed to create trace_return_stack in sysfs\n"); + } + if (etmccer & ETMCCER_TIMESTAMPING_IMPLEMENTED) { ret = sysfs_create_file(&dev->dev.kobj, &trace_timestamp_attr.attr); -- 2.39.5