Commit 5402d25a authored by Anshuman Khandual's avatar Anshuman Khandual Committed by Peter Zijlstra
Browse files

perf: Capture branch privilege information 



Platforms like arm64 could capture privilege level information for all the
branch records. Hence this adds a new element in the struct branch_entry to
record the privilege level information, which could be requested through a
new event.attr.branch_sample_type based flag PERF_SAMPLE_BRANCH_PRIV_SAVE.
This flag helps user choose whether privilege information is captured.

Signed-off-by: default avatarAnshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarJames Clark <james.clark@arm.com>
Link: https://lkml.kernel.org/r/20220824044822.70230-4-anshuman.khandual@arm.com
parent b190bc4a

include/uapi/linux/perf_event.h

+13 −1
Original line number Diff line number Diff line
@@ -204,6 +204,8 @@ enum perf_branch_sample_type_shift { 


	PERF_SAMPLE_BRANCH_HW_INDEX_SHIFT	= 17, /* save low level index of raw branch records */



	PERF_SAMPLE_BRANCH_PRIV_SAVE_SHIFT	= 18, /* save privilege mode */



	PERF_SAMPLE_BRANCH_MAX_SHIFT		/* non-ABI */

};
@@ -233,6 +235,8 @@ enum perf_branch_sample_type { 


	PERF_SAMPLE_BRANCH_HW_INDEX	= 1U << PERF_SAMPLE_BRANCH_HW_INDEX_SHIFT,



	PERF_SAMPLE_BRANCH_PRIV_SAVE	= 1U << PERF_SAMPLE_BRANCH_PRIV_SAVE_SHIFT,



	PERF_SAMPLE_BRANCH_MAX		= 1U << PERF_SAMPLE_BRANCH_MAX_SHIFT,

};
@@ -282,6 +286,13 @@ enum { 
	PERF_BR_NEW_MAX,

};



enum {

	PERF_BR_PRIV_UNKNOWN	= 0,

	PERF_BR_PRIV_USER	= 1,

	PERF_BR_PRIV_KERNEL	= 2,

	PERF_BR_PRIV_HV		= 3,

};



#define PERF_SAMPLE_BRANCH_PLM_ALL \

	(PERF_SAMPLE_BRANCH_USER|\

	 PERF_SAMPLE_BRANCH_KERNEL|\
@@ -1402,7 +1413,8 @@ struct perf_branch_entry { 
		type:4,     /* branch type */

		spec:2,     /* branch speculation info */

		new_type:4, /* additional branch type */

		reserved:34;

		priv:3,     /* privilege level */

		reserved:31;

};



union perf_sample_weight {