linux-kernel - [PATCH v5 4/6] arm64: initialise SCTLR2_EL1 at cpu_soft

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250917145618.1232329-5-yeoreum.yun@arm.com>
Date: Wed, 17 Sep 2025 15:56:16 +0100
From: Yeoreum Yun <yeoreum.yun@....com>
To: catalin.marinas@....com,
	will@...nel.org,
	broonie@...nel.org,
	oliver.upton@...ux.dev,
	anshuman.khandual@....com,
	robh@...nel.org,
	james.morse@....com,
	mark.rutland@....com,
	joey.gouly@....com,
	Dave.Martin@....com,
	ahmed.genidi@....com,
	kevin.brodsky@....com,
	scott@...amperecomputing.com,
	mbenes@...e.cz,
	james.clark@...aro.org,
	frederic@...nel.org,
	rafael@...nel.org,
	pavel@...nel.org,
	ryan.roberts@....com,
	suzuki.poulose@....com,
	maz@...nel.org
Cc: linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org,
	kvmarm@...ts.linux.dev,
	Yeoreum Yun <yeoreum.yun@....com>
Subject: [PATCH v5 4/6] arm64: initialise SCTLR2_EL1 at cpu_soft_restart()

Explicitly initialize the SCTLR2_ELx register before launching
a new kernel via kexec() to avoid leaving SCTLR2_ELx with an
arbitrary value when the new kernel runs.

Signed-off-by: Yeoreum Yun <yeoreum.yun@....com>
---
 arch/arm64/kernel/cpu-reset.S      | 3 +++
 arch/arm64/kvm/hyp/nvhe/hyp-init.S | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/arch/arm64/kernel/cpu-reset.S b/arch/arm64/kernel/cpu-reset.S
index c87445dde674..e2abc8f8c067 100644
--- a/arch/arm64/kernel/cpu-reset.S
+++ b/arch/arm64/kernel/cpu-reset.S
@@ -30,6 +30,9 @@
  * flat identity mapping.
  */
 SYM_TYPED_FUNC_START(cpu_soft_restart)
+	mov_q	x12, INIT_SCTLR2_EL1
+	set_sctlr2_elx	1, x12, x8
+
 	mov_q	x12, INIT_SCTLR_EL1_MMU_OFF
 	pre_disable_mmu_workaround
 	/*
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
index aada42522e7b..cc569656fe35 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
@@ -255,6 +255,9 @@ SYM_CODE_START(__kvm_handle_stub_hvc)
 	mov	x0, xzr
 reset:
 	/* Reset kvm back to the hyp stub. */
+	mov_q 	x5, INIT_SCTLR2_EL2
+	set_sctlr2_elx	2, x5, x4
+
 	mov_q	x5, INIT_SCTLR_EL2_MMU_OFF
 	pre_disable_mmu_workaround
 	msr	sctlr_el2, x5
-- 
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}