Commit 91ebe8bc authored by Steven Rostedt (VMware)'s avatar Steven Rostedt (VMware)
Browse files

tracing/perf: Add interrupt_context_level() helper 

Now that there are three different instances of doing the addition trick
to the preempt_count() and NMI_MASK, HARDIRQ_MASK and SOFTIRQ_OFFSET
macros, it deserves a helper function defined in the preempt.h header.

Add the interrupt_context_level() helper and replace the three instances
that do that logic with it.

Link: https://lore.kernel.org/all/20211015142541.4badd8a9@gandalf.local.home/



Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 9b84fadc

include/linux/preempt.h

+21 −0
Original line number Diff line number Diff line
@@ -77,6 +77,27 @@ 
/* preempt_count() and related functions, depends on PREEMPT_NEED_RESCHED */

#include <asm/preempt.h>



/**

 * interrupt_context_level - return interrupt context level

 *

 * Returns the current interrupt context level.

 *  0 - normal context

 *  1 - softirq context

 *  2 - hardirq context

 *  3 - NMI context

 */

static __always_inline unsigned char interrupt_context_level(void)

{

	unsigned long pc = preempt_count();

	unsigned char level = 0;



	level += !!(pc & (NMI_MASK));

	level += !!(pc & (NMI_MASK | HARDIRQ_MASK));

	level += !!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET));



	return level;

}



#define nmi_count()	(preempt_count() & NMI_MASK)

#define hardirq_count()	(preempt_count() & HARDIRQ_MASK)

#ifdef CONFIG_PREEMPT_RT

include/linux/trace_recursion.h

+1 −6
Original line number Diff line number Diff line
@@ -136,12 +136,7 @@ enum { 


static __always_inline int trace_get_context_bit(void)

{

	unsigned long pc = preempt_count();

	unsigned char bit = 0;



	bit += !!(pc & (NMI_MASK));

	bit += !!(pc & (NMI_MASK | HARDIRQ_MASK));

	bit += !!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET));

	unsigned char bit = interrupt_context_level();



	return TRACE_CTX_NORMAL - bit;

}

kernel/events/internal.h

+1 −6
Original line number Diff line number Diff line
@@ -205,12 +205,7 @@ DEFINE_OUTPUT_COPY(__output_copy_user, arch_perf_out_copy_user) 


static inline int get_recursion_context(int *recursion)

{

	unsigned int pc = preempt_count();

	unsigned char rctx = 0;



	rctx += !!(pc & (NMI_MASK));

	rctx += !!(pc & (NMI_MASK | HARDIRQ_MASK));

	rctx += !!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET));

	unsigned char rctx = interrupt_context_level();



	if (recursion[rctx])

		return -1;

kernel/trace/ring_buffer.c

+1 −6
Original line number Diff line number Diff line
@@ -3167,12 +3167,7 @@ static __always_inline int 
trace_recursive_lock(struct ring_buffer_per_cpu *cpu_buffer)

{

	unsigned int val = cpu_buffer->current_context;

	unsigned long pc = preempt_count();

	int bit = 0;



	bit += !!(pc & (NMI_MASK));

	bit += !!(pc & (NMI_MASK | HARDIRQ_MASK));

	bit += !!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET));

	int bit = interrupt_context_level();



	bit = RB_CTX_NORMAL - bit;