linux-kernel - [PATCH v14 2/5] arm64/gcs: Ensure FGTs for EL1 GCS instructions are disabled

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Message-Id: <20241005-arm64-gcs-v14-2-59060cd6092b@kernel.org>
Date: Sat, 05 Oct 2024 11:37:29 +0100
From: Mark Brown <broonie@...nel.org>
To: Catalin Marinas <catalin.marinas@....com>, 
 Will Deacon <will@...nel.org>, Marc Zyngier <maz@...nel.org>, 
 Oliver Upton <oliver.upton@...ux.dev>, Joey Gouly <joey.gouly@....com>, 
 Suzuki K Poulose <suzuki.poulose@....com>, Shuah Khan <shuah@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org, linux-doc@...r.kernel.org, 
 kvmarm@...ts.linux.dev, linux-kselftest@...r.kernel.org, 
 linux-kernel@...r.kernel.org, Mark Brown <broonie@...nel.org>
Subject: [PATCH v14 2/5] arm64/gcs: Ensure FGTs for EL1 GCS instructions
 are disabled

The initial EL2 setup for GCS did not include disabling of EL1 usage of
GCS instructions, also disable these traps.  This is the first disabling
of instruction traps, use x2 to store the value to be written.

Signed-off-by: Mark Brown <broonie@...nel.org>
---
 arch/arm64/include/asm/el2_setup.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h
index 27086a81eae34483a682681ab1be1959a339527a..99e887a5b2190f8810f1ed22d35b7acd26d2fd1e 100644
--- a/arch/arm64/include/asm/el2_setup.h
+++ b/arch/arm64/include/asm/el2_setup.h
@@ -170,6 +170,7 @@
 	cbz	x1, .Lskip_fgt_\@
 
 	mov	x0, xzr
+	mov     x2, xzr
 	mrs	x1, id_aa64dfr0_el1
 	ubfx	x1, x1, #ID_AA64DFR0_EL1_PMSVer_SHIFT, #4
 	cmp	x1, #3
@@ -217,10 +218,14 @@
 	orr	x0, x0, #HFGxTR_EL2_nGCS_EL1_MASK
 	orr	x0, x0, #HFGxTR_EL2_nGCS_EL0_MASK
 
+	orr	x2, x2, #HFGITR_EL2_nGCSEPP_MASK
+	orr	x2, x2, #HFGITR_EL2_nGCSSTR_EL1_MASK
+	orr	x2, x2, #HFGITR_EL2_nGCSPUSHM_EL1_MASK
+
 .Lset_fgt_\@:
 	msr_s	SYS_HFGRTR_EL2, x0
 	msr_s	SYS_HFGWTR_EL2, x0
-	msr_s	SYS_HFGITR_EL2, xzr
+	msr_s	SYS_HFGITR_EL2, x2
 
 	mrs	x1, id_aa64pfr0_el1		// AMU traps UNDEF without AMU
 	ubfx	x1, x1, #ID_AA64PFR0_EL1_AMU_SHIFT, #4

-- 
2.39.2