From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: Mark Rutland <mark.rutland@arm.com>,
Vladimir Murzin <vladimir.murzin@arm.com>,
Arnd Bergmann <arnd@arndb.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Linus Walleij <linusw@kernel.org>,
linux-kernel@vger.kernel.org, Mostafa Saleh <smostafa@google.com>,
Marc Zyngier <maz@kernel.org>,
David Hildenbrand <david@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>,
Oliver Upton <oupton@kernel.org>, Will Deacon <will@kernel.org>,
Ard Biesheuvel <ardb@kernel.org>
Subject: [PATCH 12/21] KVM: arm64: Preserve handler/thread bit of EL1 mode in __finalise_el2()
Date: Mon, 7 Sep 2026 17:42:37 +0100 [thread overview]
Message-ID: <20260907164247.17223-13-will@kernel.org> (raw)
In-Reply-To: <20260907164247.17223-1-will@kernel.org>
__finalise_el2() unconditionally returns to EL2h when VHE is being used.
In preparation for handling callers from both EL1h and EL1t, preserve
the handler/thread bit of the calling mode when rewriting the exception
level in the SPSR.
Signed-off-by: Will Deacon <will@kernel.org>
---
arch/arm64/include/uapi/asm/ptrace.h | 1 +
arch/arm64/kernel/hyp-stub.S | 7 ++++---
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/uapi/asm/ptrace.h b/arch/arm64/include/uapi/asm/ptrace.h
index 15649a253a57..25d9d9a0a6f7 100644
--- a/arch/arm64/include/uapi/asm/ptrace.h
+++ b/arch/arm64/include/uapi/asm/ptrace.h
@@ -37,6 +37,7 @@
#define PSR_MODE_EL3t 0x0000000c
#define PSR_MODE_EL3h 0x0000000d
#define PSR_MODE_MASK 0x0000000f
+#define PSR_MODE_h_BIT 0x00000001
/* AArch32 CPSR bits */
#define PSR_MODE32_BIT 0x00000010
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 37c6976e44a4..f61778cccd3c 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -149,10 +149,11 @@ SYM_CODE_START_LOCAL(__finalise_el2)
isb
- // Hack the exception return to stay at EL2
+ // Hack the exception return to stay at EL2 ...
mrs x0, spsr_el1
- and x0, x0, #~PSR_MODE_MASK
- mov x1, #PSR_MODE_EL2h
+ // ... preserving the 'h' bit so we don't swizzle SP.
+ and x0, x0, #(~PSR_MODE_MASK | PSR_MODE_h_BIT)
+ mov x1, #PSR_MODE_EL2t
orr x0, x0, x1
msr spsr_el1, x0
--
2.55.0.979.g7e5102b832-goog
next prev parent reply other threads:[~2026-09-07 16:43 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-07 16:42 [PATCH 00/21] arm64: Move overflow sp into SP_EL1 and kernel sp into SP_EL0 Will Deacon
2026-09-07 16:42 ` [PATCH 01/21] arm64: entry: Defer setting of TPIDRRO_EL0 until exit to userspace Will Deacon
2026-09-11 7:53 ` Jinjie Ruan
2026-09-07 16:42 ` [PATCH 02/21] arm64: entry: Only check for stack overflow on exceptions from EL1 Will Deacon
2026-09-07 16:42 ` [PATCH 03/21] arm64: stackprotector: Temporarily disable per-task stackprotector Will Deacon
2026-09-07 16:42 ` [PATCH 04/21] arm64: bpf: Add support for generating reads of TPIDRRO_EL0 Will Deacon
2026-09-07 16:42 ` [PATCH 05/21] KVM: arm64: Protect TPIDRRO_EL0 across guest entry/exit Will Deacon
2026-09-07 16:42 ` [PATCH 06/21] arm64: Store 'current' in TPIDRRO_EL0 instead of SP_EL0 Will Deacon
2026-09-08 13:19 ` David Laight
2026-09-11 12:57 ` Will Deacon
2026-09-07 16:42 ` [PATCH 07/21] selftests/bpf: arm64: Use TPIDRRO_EL0 instead of SP_EL0 for 'current' Will Deacon
2026-09-07 16:42 ` [PATCH 08/21] scripts/gdb: " Will Deacon
2026-09-07 16:42 ` [PATCH 09/21] arm64: stackprotector: Re-enable per-task stackprotector Will Deacon
2026-09-07 16:42 ` [PATCH 10/21] arm64: percpu: Specialise set_my_cpu_offset() for the primary CPU Will Deacon
2026-09-07 16:42 ` [PATCH 11/21] arm64: percpu: Annotate __kern_my_cpu_offset() as '__always_inline' Will Deacon
2026-09-07 16:42 ` Will Deacon [this message]
2026-09-07 16:42 ` [PATCH 13/21] arm64: sdei: Guard most of asm/sdei.h with CONFIG_ARM_SDE_INTERFACE Will Deacon
2026-09-07 16:42 ` [PATCH 14/21] arm64: sdei: Support SDEI events from kernel handler and thread modes Will Deacon
2026-09-07 16:42 ` [PATCH 15/21] arm64: entry: Point SP_EL0 at the overflow stack Will Deacon
2026-09-07 16:42 ` [PATCH 16/21] arm64: entry: Implement EL1t exception handlers for " Will Deacon
2026-09-07 16:42 ` [PATCH 17/21] arm64: entry: Use SPSel to switch to " Will Deacon
2026-09-07 16:42 ` [PATCH 18/21] arm64: entry: Split up kernel_ventry macro into separate helper macros Will Deacon
2026-09-07 16:42 ` [PATCH 19/21] arm64: entry: The great stack switcheroo Will Deacon
2026-09-08 11:30 ` Will Deacon
2026-09-07 16:42 ` [PATCH 20/21] arm64: tracing: Advertise a mode of EL1t in synthetic kernel regs Will Deacon
2026-09-07 16:42 ` [PATCH 21/21] arm64: Rename 'overflow_stack' and OVERFLOW_STACK_SIZE Will Deacon
2026-09-09 10:39 ` [PATCH 00/21] arm64: Move overflow sp into SP_EL1 and kernel sp into SP_EL0 Vladimir Murzin
2026-09-09 11:29 ` Will Deacon
2026-09-10 13:49 ` Vladimir Murzin
2026-09-11 12:57 ` Will Deacon
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