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From: Alexandru Elisei <alexandru.elisei@arm.com>
To: mark.rutland@arm.com, linux-arm-kernel@lists.infradead.org
Subject: [boot-wrapper PATCH] aarch64: Do not trap PMSNEVFR_EL1
Date: Tue, 17 Aug 2021 17:34:20 +0100	[thread overview]
Message-ID: <20210817163420.813631-1-alexandru.elisei@arm.com> (raw)

FEAT_PMUv1p2 adds a new register, PMSNEVFR_EL1, and a new MDCR_EL3 trap bit
for it, EnPMSN. Set the bit to 1 to allow lower exception levels direct
access to the register.

Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
---
 arch/aarch64/boot.S | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/aarch64/boot.S b/arch/aarch64/boot.S
index 2215f7ed3a1f..8951f1e4676a 100644
--- a/arch/aarch64/boot.S
+++ b/arch/aarch64/boot.S
@@ -88,8 +88,12 @@ ASM_FUNC(_start)
 	cbz	x1, 1f
 
 	// Enable SPE for the non-secure world.
-	ldr	x1, =(0x3 << 12)
-	orr	x0, x0, x1
+	ldr	x2, =(0x3 << 12)
+	orr	x0, x0, x2
+	cmp	x1, #3
+	b.lt	1
+	// Do not trap PMSNEVFR_EL1.
+	orr	x0, x0, #(1 << 36)
 
 1:	mrs	x1, id_aa64dfr0_el1
 	ubfx	x1, x1, #44, #4
-- 
2.32.0


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             reply	other threads:[~2021-08-17 16:35 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-17 16:34 Alexandru Elisei [this message]
2021-08-18 14:12 ` [boot-wrapper PATCH] aarch64: Do not trap PMSNEVFR_EL1 Mark Rutland

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