Commit e0e21764 authored by Yicong Yang's avatar Yicong Yang Committed by Junhao He
Browse files

arm64: arm_pmuv3: Correctly extract and check the PMUVer 

maillist inclusion
category: bugifx
bugzilla: https://gitee.com/openeuler/kernel/issues/I9J01A
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/commit/?h=for-next/perf&id=b782e8d07baac95a5ce3f8773cc61f4ed7d0ccbc



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Currently we're using "sbfx" to extract the PMUVer from ID_AA64DFR0_EL1
and skip the init/reset if no PMU present when the extracted PMUVer is
negative or is zero. However for PMUv3p8 the PMUVer will be 0b1000 and
PMUVer extracted by "sbfx" will always be negative and we'll skip the
init/reset in __init_el2_debug/reset_pmuserenr_el0 unexpectedly.

So this patch use "ubfx" instead of "sbfx" to extract the PMUVer. If
the PMUVer is implementation defined (0b1111) or not implemented(0b0000)
then skip the reset/init. Previously we'll also skip the init/reset
if the PMUVer is higher than the version we known (currently PMUv3p9),
with this patch we'll only skip if the PMU is not implemented or
implementation defined. This keeps consistence with how we probe
the PMU in the driver with pmuv3_implemented().

Signed-off-by: default avatarYicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/20240411123030.7201-1-yangyicong@huawei.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
Signed-off-by: default avatarJunhao He <hejunhao3@huawei.com>
parent 27467fc2

arch/arm64/include/asm/assembler.h

+4 −3
Original line number Diff line number Diff line
@@ -516,9 +516,10 @@ alternative_endif 
 */

	.macro	reset_pmuserenr_el0, tmpreg

	mrs	\tmpreg, id_aa64dfr0_el1

	sbfx	\tmpreg, \tmpreg, #ID_AA64DFR0_EL1_PMUVer_SHIFT, #4

	cmp	\tmpreg, #1			// Skip if no PMU present

	b.lt	9000f

	ubfx	\tmpreg, \tmpreg, #ID_AA64DFR0_EL1_PMUVer_SHIFT, #4

	cmp	\tmpreg, #ID_AA64DFR0_EL1_PMUVer_NI

	ccmp	\tmpreg, #ID_AA64DFR0_EL1_PMUVer_IMP_DEF, #4, ne

	b.eq	9000f				// Skip if no PMU present or IMP_DEF

	msr	pmuserenr_el0, xzr		// Disable PMU access from EL0

9000:

	.endm

arch/arm64/include/asm/el2_setup.h

+5 −4
Original line number Diff line number Diff line
@@ -59,13 +59,14 @@ 


.macro __init_el2_debug

	mrs	x1, id_aa64dfr0_el1

	sbfx	x0, x1, #ID_AA64DFR0_EL1_PMUVer_SHIFT, #4

	cmp	x0, #1

	b.lt	.Lskip_pmu_\@			// Skip if no PMU present

	ubfx	x0, x1, #ID_AA64DFR0_EL1_PMUVer_SHIFT, #4

	cmp	x0, #ID_AA64DFR0_EL1_PMUVer_NI

	ccmp	x0, #ID_AA64DFR0_EL1_PMUVer_IMP_DEF, #4, ne

	b.eq	.Lskip_pmu_\@			// Skip if no PMU present or IMP_DEF

	mrs	x0, pmcr_el0			// Disable debug access traps

	ubfx	x0, x0, #11, #5			// to EL2 and allow access to

.Lskip_pmu_\@:

	csel	x2, xzr, x0, lt			// all PMU counters from EL1

	csel	x2, xzr, x0, eq			// all PMU counters from EL1



	/* Statistical profiling */

	ubfx	x0, x1, #ID_AA64DFR0_EL1_PMSVer_SHIFT, #4