Commit d14dd7e2 authored by Ari Kauppi's avatar Ari Kauppi Committed by Robert Richter
Browse files

ARM: oprofile: Fix backtraces in timer mode 



Always allow backtraces when using oprofile on ARM, even if a PMU
isn't present. Restores functionality originally introduced in commit
1b7b5698 ("oprofile: Always allow
backtraces on ARM") by Richard Purdie.

It is not that obvious, but there is now only one oprofile_arch_init()
function. So the .backtrace callback is available also in timer mode.

Implemented by removing code and using stubs for oprofile_perf_{init,
exit} provided by <linux/oprofile.h>. This allows cleaning of other
architecture specific implementations too.

Cc: stable@kernel.org # 37.x
Signed-off-by: default avatarAri Kauppi <kauppi@papupata.org>
Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarRobert Richter <robert.richter@amd.com>
parent 1ea1bdf7

arch/arm/oprofile/common.c

+2 −10
Original line number Diff line number Diff line
@@ -10,8 +10,6 @@ 
 */



#include <linux/cpumask.h>

#include <linux/err.h>

#include <linux/errno.h>

#include <linux/init.h>

#include <linux/mutex.h>

#include <linux/oprofile.h>
@@ -46,6 +44,7 @@ char *op_name_from_perf_id(void) 
		return NULL;

	}

}

#endif



static int report_trace(struct stackframe *frame, void *d)

{
@@ -111,6 +110,7 @@ static void arm_backtrace(struct pt_regs * const regs, unsigned int depth) 


int __init oprofile_arch_init(struct oprofile_operations *ops)

{

	/* provide backtrace support also in timer mode: */

	ops->backtrace		= arm_backtrace;



	return oprofile_perf_init(ops);
@@ -120,11 +120,3 @@ void __exit oprofile_arch_exit(void) 
{

	oprofile_perf_exit();

}
 
#else

int __init oprofile_arch_init(struct oprofile_operations *ops)

{

	pr_info("oprofile: hardware counters not available\n");

	return -ENODEV;

}

void __exit oprofile_arch_exit(void) {}

#endif /* CONFIG_HW_PERF_EVENTS */

include/linux/oprofile.h

+9 −0
Original line number Diff line number Diff line
@@ -16,6 +16,8 @@ 
#include <linux/types.h>

#include <linux/spinlock.h>

#include <linux/init.h>

#include <linux/errno.h>

#include <linux/printk.h>

#include <asm/atomic.h>

 

/* Each escaped entry is prefixed by ESCAPE_CODE
@@ -190,6 +192,13 @@ int oprofile_write_commit(struct op_entry *entry); 
int __init oprofile_perf_init(struct oprofile_operations *ops);

void oprofile_perf_exit(void);

char *op_name_from_perf_id(void);

#else

static inline int __init oprofile_perf_init(struct oprofile_operations *ops)

{

	pr_info("oprofile: hardware counters not available\n");

	return -ENODEV;

}

static inline void oprofile_perf_exit(void) { }

#endif /* CONFIG_HW_PERF_EVENTS */



#endif /* OPROFILE_H */

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