Commit 73760931 authored by Anshuman Khandual's avatar Anshuman Khandual Committed by Benjamin Herrenschmidt
Browse files

powerpc/perf: Add basic assembly code to read BHRB entries on POWER8 



This patch adds the basic assembly code to read BHRB buffer. BHRB entries
are valid only after a PMU interrupt has happened (when MMCR0[PMAO]=1)
and BHRB has been freezed. BHRB read should not be attempted when it is
still enabled (MMCR0[PMAE]=1) and getting updated, as this can produce
non-deterministic results.

Signed-off-by: default avatarAnshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 95213959

arch/powerpc/perf/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ subdir-ccflags-$(CONFIG_PPC_WERROR) := -Werror 


obj-$(CONFIG_PERF_EVENTS)	+= callchain.o



obj-$(CONFIG_PPC_PERF_CTRS)	+= core-book3s.o

obj-$(CONFIG_PPC_PERF_CTRS)	+= core-book3s.o bhrb.o

obj64-$(CONFIG_PPC_PERF_CTRS)	+= power4-pmu.o ppc970-pmu.o power5-pmu.o \

				   power5+-pmu.o power6-pmu.o power7-pmu.o \

				   power8-pmu.o

arch/powerpc/perf/bhrb.S

0 → 100644
+44 −0
Original line number Diff line number Diff line 
/*

 * Basic assembly code to read BHRB entries

 *

 * Copyright 2013 Anshuman Khandual, IBM Corporation.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version

 * 2 of the License, or (at your option) any later version.

 */

#include <asm/ppc_asm.h>

#include <asm/ppc-opcode.h>



	.text



.balign 8



/* r3 = n  (where n = [0-31])

 * The maximum number of BHRB entries supported with PPC_MFBHRBE instruction

 * is 1024. We have limited number of table entries here as POWER8 implements

 * 32 BHRB entries.

 */



/* .global read_bhrb */

_GLOBAL(read_bhrb)

	cmpldi	r3,31

	bgt	1f

	ld	r4,bhrb_table@got(r2)

	sldi	r3,r3,3

	add	r3,r4,r3

	mtctr	r3

	bctr

1:	li	r3,0

	blr



#define MFBHRB_TABLE1(n) PPC_MFBHRBE(R3,n); blr

#define MFBHRB_TABLE2(n) MFBHRB_TABLE1(n); MFBHRB_TABLE1(n+1)

#define MFBHRB_TABLE4(n) MFBHRB_TABLE2(n); MFBHRB_TABLE2(n+2)

#define MFBHRB_TABLE8(n) MFBHRB_TABLE4(n); MFBHRB_TABLE4(n+4)

#define MFBHRB_TABLE16(n) MFBHRB_TABLE8(n); MFBHRB_TABLE8(n+8)

#define MFBHRB_TABLE32(n) MFBHRB_TABLE16(n); MFBHRB_TABLE16(n+16)



bhrb_table:

	MFBHRB_TABLE32(0)

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