Subject: [PATCH RFC 4.9 4/5] arm64: move !VHE work to end of el2_setup

From: Nathan Chancellor <[email-masked]>
Date: Fri, 7 Jan 2022 12:43:34 -0700

From: Mark Rutland <[email-masked]>

commit d61c97a7773d0848b4bf5c4697855c7ce117362c upstream.

We only need to initialise sctlr_el1 if we're installing an EL2 stub, so
we may as well defer this until we're doing so. Similarly, we can defer
intialising CPTR_EL2 until then, as we do not access any trapped
functionality as part of el2_setup.

This patch modified el2_setup accordingly, allowing us to remove a
branch and simplify the code flow.

Acked-by: Marc Zyngier <[email-masked]>
Signed-off-by: Mark Rutland <[email-masked]>
Cc: Will Deacon <[email-masked]>
Signed-off-by: Catalin Marinas <[email-masked]>
Signed-off-by: Nathan Chancellor <[email-masked]>
---
 arch/arm64/kernel/head.S | 37 +++++++++++++++++--------------------
 1 file changed, 17 insertions(+), 20 deletions(-)

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index b15abc6ae4af..c067b13e93cc 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -553,26 +553,6 @@ set_hcr:
 	msr	vpidr_el2, x0
 	msr	vmpidr_el2, x1
 
-	/*
-	 * When VHE is not in use, early init of EL2 and EL1 needs to be
-	 * done here.
-	 * When VHE _is_ in use, EL1 will not be used in the host and
-	 * requires no configuration, and all non-hyp-specific EL2 setup
-	 * will be done via the _EL1 system register aliases in __cpu_setup.
-	 */
-	cbnz	x2, 1f
-
-	/* sctlr_el1 */
-	mov	x0, #0x0800			// Set/clear RES{1,0} bits
-CPU_BE(	movk	x0, #0x33d0, lsl #16	)	// Set EE and E0E on BE systems
-CPU_LE(	movk	x0, #0x30d0, lsl #16	)	// Clear EE and E0E on LE systems
-	msr	sctlr_el1, x0
-
-	/* Coprocessor traps. */
-	mov	x0, #0x33ff
-	msr	cptr_el2, x0			// Disable copro. traps to EL2
-1:
-
 #ifdef CONFIG_COMPAT
 	msr	hstr_el2, xzr			// Disable CP15 traps to EL2
 #endif
@@ -598,6 +578,23 @@ CPU_LE(	movk	x0, #0x30d0, lsl #16	)	// Clear EE and E0E on LE systems
 	ret
 
 install_el2_stub:
+	/*
+	 * When VHE is not in use, early init of EL2 and EL1 needs to be
+	 * done here.
+	 * When VHE _is_ in use, EL1 will not be used in the host and
+	 * requires no configuration, and all non-hyp-specific EL2 setup
+	 * will be done via the _EL1 system register aliases in __cpu_setup.
+	 */
+	/* sctlr_el1 */
+	mov	x0, #0x0800			// Set/clear RES{1,0} bits
+CPU_BE(	movk	x0, #0x33d0, lsl #16	)	// Set EE and E0E on BE systems
+CPU_LE(	movk	x0, #0x30d0, lsl #16	)	// Clear EE and E0E on LE systems
+	msr	sctlr_el1, x0
+
+	/* Coprocessor traps. */
+	mov	x0, #0x33ff
+	msr	cptr_el2, x0			// Disable copro. traps to EL2
+
 	/* Hypervisor stub */
 	adrp	x0, __hyp_stub_vectors
 	add	x0, x0, #:lo12:__hyp_stub_vectors
-- 
2.34.1

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