[RFC PATCH v2 13/15] tracing: of: Add cpumask property support

Masami Hiramatsu
2019-07-15T05:13:35Z

Add cpumask property for tracing. Note that this property accepts
a string cpumask, not a digit number.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
kernel/trace/trace.c | 41 ++++++++++++++++++++++++++++-------------
kernel/trace/trace_of.c | 14 ++++++++++++++
2 files changed, 42 insertions(+), 13 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 6f50c58a3ad4..251d9de14b12 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4437,20 +4437,12 @@ tracing_cpumask_read(struct file *filp, char __user *ubuf,
return count;
}

-static ssize_t
-tracing_cpumask_write(struct file *filp, const char __user *ubuf,
- size_t count, loff_t *ppos)
+int tracing_set_cpumask(struct trace_array *tr, cpumask_var_t tracing_cpumask_new)
{
- struct trace_array *tr = file_inode(filp)->i_private;
- cpumask_var_t tracing_cpumask_new;
- int err, cpu;
-
- if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
- return -ENOMEM;
+ int cpu;

- err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
- if (err)
- goto err_unlock;
+ if (!tr)
+ return -EINVAL;

local_irq_disable();
arch_spin_lock(&tr->max_lock);
@@ -4474,11 +4466,34 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf,
local_irq_enable();

cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
+
+ return 0;
+}
+
+static ssize_t
+tracing_cpumask_write(struct file *filp, const char __user *ubuf,
+ size_t count, loff_t *ppos)
+{
+ struct trace_array *tr = file_inode(filp)->i_private;
+ cpumask_var_t tracing_cpumask_new;
+ int err;
+
+ if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
+ return -ENOMEM;
+
+ err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
+ if (err)
+ goto err_free;
+
+ err = tracing_set_cpumask(tr, tracing_cpumask_new);
+ if (err)
+ goto err_free;
+
free_cpumask_var(tracing_cpumask_new);

return count;

-err_unlock:
+err_free:
free_cpumask_var(tracing_cpumask_new);

return err;
diff --git a/kernel/trace/trace_of.c b/kernel/trace/trace_of.c
index 7fe81c25dc59..14d6c9a8fd81 100644
--- a/kernel/trace/trace_of.c
+++ b/kernel/trace/trace_of.c
@@ -22,6 +22,8 @@ extern void __init trace_init_tracepoint_printk(void);
extern ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
unsigned long size, int cpu_id);
extern struct trace_array *trace_array_create(const char *name);
+extern int tracing_set_cpumask(struct trace_array *tr,
+ cpumask_var_t tracing_cpumask_new);

static void __init
trace_of_set_instance_options(struct trace_array *tr, struct device_node *node)
@@ -59,6 +61,18 @@ trace_of_set_instance_options(struct trace_array *tr, struct device_node *node)
pr_err("Failed to resize trace buffer to %d KB\n",
v >> 10);
}
+
+ err = of_property_read_string(node, "cpumask", &p);
+ if (!err) {
+ cpumask_var_t new_mask;
+
+ if (alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
+ if (cpumask_parse(p, new_mask) < 0 ||
+ tracing_set_cpumask(tr, new_mask) < 0)
+ pr_err("Failed to set new CPU mask %s\n", p);
+ free_cpumask_var(new_mask);
+ }
+ }
}

static void __init