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[PATCH v5 5/7] arm64: head: Init PMSCR_EL2.{PA,PCT} when entered at EL2 without VHE

From Will Deacon <will.deacon@arm.com>
Newsgroups linux.kernel
Subject [PATCH v5 5/7] arm64: head: Init PMSCR_EL2.{PA,PCT} when entered at EL2 without VHE
Date 2017-09-28 16:20 +0200
Message-ID <uuHPt-1Bi-23@gated-at.bofh.it> (permalink)
References <uuHFM-1y2-21@gated-at.bofh.it>
Organization linux.* mail to news gateway

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When booting at EL2, ensure that we permit the EL1 host to sample
physical addresses and physical counter values using SPE.

Signed-off-by: Will Deacon <will.deacon@arm.com>
---
 arch/arm64/kernel/head.S | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 7434ec0c7a27..c370e270ae55 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -479,14 +479,21 @@ set_hcr:
 
 	/* Statistical profiling */
 	ubfx	x0, x1, #32, #4			// Check ID_AA64DFR0_EL1 PMSVer
-	cbz	x0, 6f				// Skip if SPE not present
-	cbnz	x2, 5f				// VHE?
+	cbz	x0, 7f				// Skip if SPE not present
+	cbnz	x2, 6f				// VHE?
+	mrs_s	x4, SYS_PMBIDR_EL1		// If SPE available at EL2,
+	and	x4, x4, #(1 << SYS_PMBIDR_EL1_P_SHIFT)
+	cbnz	x4, 5f				// then permit sampling of physical
+	mov	x4, #(1 << SYS_PMSCR_EL2_PCT_SHIFT | \
+		      1 << SYS_PMSCR_EL2_PA_SHIFT)
+	msr_s	SYS_PMSCR_EL2, x4		// addresses and physical counter
+5:
 	mov	x1, #(MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT)
 	orr	x3, x3, x1			// If we don't have VHE, then
-	b	6f				// use EL1&0 translation.
-5:						// For VHE, use EL2 translation
+	b	7f				// use EL1&0 translation.
+6:						// For VHE, use EL2 translation
 	orr	x3, x3, #MDCR_EL2_TPMS		// and disable access from EL1
-6:
+7:
 	msr	mdcr_el2, x3			// Configure debug traps
 
 	/* Stage-2 translation */
-- 
2.1.4

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Thread

[PATCH v5 0/7] Add support for the ARMv8.2 Statistical Profiling Extension Will Deacon <will.deacon@arm.com> - 2017-09-28 16:20 +0200
  [PATCH v5 4/7] arm64: sysreg: Move SPE registers and PSB into common header files Will Deacon <will.deacon@arm.com> - 2017-09-28 16:20 +0200
    Re: [PATCH v5 4/7] arm64: sysreg: Move SPE registers and PSB into  common header files Mark Rutland <mark.rutland@arm.com> - 2017-10-02 12:00 +0200
    Re: [PATCH v5 4/7] arm64: sysreg: Move SPE registers and PSB into  common header files Marc Zyngier <marc.zyngier@arm.com> - 2017-10-02 12:00 +0200
  [PATCH v5 7/7] dt-bindings: Document devicetree binding for ARM SPE Will Deacon <will.deacon@arm.com> - 2017-09-28 16:20 +0200
    Re: [PATCH v5 7/7] dt-bindings: Document devicetree binding for ARM  SPE Mark Rutland <mark.rutland@arm.com> - 2017-10-02 12:10 +0200
  [PATCH v5 6/7] drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension Will Deacon <will.deacon@arm.com> - 2017-09-28 16:20 +0200
    Re: [PATCH v5 6/7] drivers/perf: Add support for ARMv8.2  Statistical Profiling Extension Kim Phillips <kim.phillips@arm.com> - 2017-09-30 00:20 +0200
      Re: [PATCH v5 6/7] drivers/perf: Add support for ARMv8.2 Statistical  Profiling Extension Arnaldo Carvalho de Melo <acme@redhat.com> - 2017-10-02 22:50 +0200
  [PATCH v5 2/7] perf/core: Export AUX buffer helpers to modules Will Deacon <will.deacon@arm.com> - 2017-09-28 16:20 +0200
  [PATCH v5 5/7] arm64: head: Init PMSCR_EL2.{PA,PCT} when entered at EL2 without VHE Will Deacon <will.deacon@arm.com> - 2017-09-28 16:20 +0200
    Re: [PATCH v5 5/7] arm64: head: Init PMSCR_EL2.{PA,PCT} when entered  at EL2 without VHE Mark Rutland <mark.rutland@arm.com> - 2017-10-02 12:10 +0200

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