oprofile: Introduce new oprofile sample add function (oprofile_add_ext_hw_sample)

This patch introduces a new oprofile sample add function
(oprofile_add_ext_hw_sample) that can also take task_struct as an
argument, which is used by the hwsampler kernel module when copying
hardware samples to OProfile buffers.

Applied with following changes:
* removed #include <linux/module.h>
* whitespace changes
* removed conditional compilation (CONFIG_HAVE_HWSAMPLER)
* modified order of functions
* fix missing function definition in header file
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Maran Pakkirisamy <maranp@linux.vnet.ibm.com>
Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>

drivers/oprofile/cpu_buffer.c

@@ -258,8 +258,10 @@ op_add_sample(struct oprofile_cpu_buffer *cpu_buf,
  */
 static int
 log_sample(struct oprofile_cpu_buffer *cpu_buf, unsigned long pc,
-	   unsigned long backtrace, int is_kernel, unsigned long event)
+	   unsigned long backtrace, int is_kernel, unsigned long event,
+	   struct task_struct *task)
 {
+	struct task_struct *tsk = task ? task : current;
 	cpu_buf->sample_received++;
 
 	if (pc == ESCAPE_CODE) {
@@ -267,7 +269,7 @@ log_sample(struct oprofile_cpu_buffer *cpu_buf, unsigned long pc,
 		return 0;
 	}
 
-	if (op_add_code(cpu_buf, backtrace, is_kernel, current))
+	if (op_add_code(cpu_buf, backtrace, is_kernel, tsk))
 		goto fail;
 
 	if (op_add_sample(cpu_buf, pc, event))
@@ -292,7 +294,8 @@ static inline void oprofile_end_trace(struct oprofile_cpu_buffer *cpu_buf)
 
 static inline void
 __oprofile_add_ext_sample(unsigned long pc, struct pt_regs * const regs,
-			  unsigned long event, int is_kernel)
+			  unsigned long event, int is_kernel,
+			  struct task_struct *task)
 {
 	struct oprofile_cpu_buffer *cpu_buf = &__get_cpu_var(op_cpu_buffer);
 	unsigned long backtrace = oprofile_backtrace_depth;
@@ -301,7 +304,7 @@ __oprofile_add_ext_sample(unsigned long pc, struct pt_regs * const regs,
 	 * if log_sample() fail we can't backtrace since we lost the
 	 * source of this event
 	 */
-	if (!log_sample(cpu_buf, pc, backtrace, is_kernel, event))
+	if (!log_sample(cpu_buf, pc, backtrace, is_kernel, event, task))
 		/* failed */
 		return;
 
@@ -313,10 +316,17 @@ __oprofile_add_ext_sample(unsigned long pc, struct pt_regs * const regs,
 	oprofile_end_trace(cpu_buf);
 }
 
+void oprofile_add_ext_hw_sample(unsigned long pc, struct pt_regs * const regs,
+				unsigned long event, int is_kernel,
+				struct task_struct *task)
+{
+	__oprofile_add_ext_sample(pc, regs, event, is_kernel, task);
+}
+
 void oprofile_add_ext_sample(unsigned long pc, struct pt_regs * const regs,
 			     unsigned long event, int is_kernel)
 {
-	__oprofile_add_ext_sample(pc, regs, event, is_kernel);
+	__oprofile_add_ext_sample(pc, regs, event, is_kernel, NULL);
 }
 
 void oprofile_add_sample(struct pt_regs * const regs, unsigned long event)
@@ -332,7 +342,7 @@ void oprofile_add_sample(struct pt_regs * const regs, unsigned long event)
 		pc = ESCAPE_CODE; /* as this causes an early return. */
 	}
 
-	__oprofile_add_ext_sample(pc, regs, event, is_kernel);
+	__oprofile_add_ext_sample(pc, regs, event, is_kernel, NULL);
 }
 
 /*
@@ -403,7 +413,7 @@ int oprofile_write_commit(struct op_entry *entry)
 void oprofile_add_pc(unsigned long pc, int is_kernel, unsigned long event)
 {
 	struct oprofile_cpu_buffer *cpu_buf = &__get_cpu_var(op_cpu_buffer);
-	log_sample(cpu_buf, pc, 0, is_kernel, event);
+	log_sample(cpu_buf, pc, 0, is_kernel, event, NULL);
 }
 
 void oprofile_add_trace(unsigned long pc)

include/linux/oprofile.h

@@ -106,6 +106,13 @@ void oprofile_add_sample(struct pt_regs * const regs, unsigned long event);
 void oprofile_add_ext_sample(unsigned long pc, struct pt_regs * const regs,
 				unsigned long event, int is_kernel);
 
+/**
+ * Add an hardware sample.
+ */
+void oprofile_add_ext_hw_sample(unsigned long pc, struct pt_regs * const regs,
+	unsigned long event, int is_kernel,
+	struct task_struct *task);
+
 /* Use this instead when the PC value is not from the regs. Doesn't
  * backtrace. */
 void oprofile_add_pc(unsigned long pc, int is_kernel, unsigned long event);