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Commit 85054035 authored by Marc Zyngier's avatar Marc Zyngier Committed by Will Deacon
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arm64: kernel: Init MDCR_EL2 even in the absence of a PMU 



Commit f436b2ac ("arm64: kernel: fix architected PMU registers
unconditional access") made sure we wouldn't access unimplemented
PMU registers, but also left MDCR_EL2 uninitialized in that case,
leading to trap bits being potentially left set.

Make sure we always write something in that register.

Fixes: f436b2ac ("arm64: kernel: fix architected PMU registers unconditional access")
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 9a1a1f40

arch/arm64/kernel/head.S

+2 −1
Original line number Diff line number Diff line
@@ -586,8 +586,9 @@ CPU_LE( movk x0, #0x30d0, lsl #16 ) // Clear EE and E0E on LE systems 
	b.lt	4f				// Skip if no PMU present

	mrs	x0, pmcr_el0			// Disable debug access traps

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

	msr	mdcr_el2, x0			// all PMU counters from EL1

4:

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

	msr	mdcr_el2, x0			// (if they exist)



	/* Stage-2 translation */

	msr	vttbr_el2, xzr