linux-kernel - [PATCH 05/11] arm64: save/restore SCTLR2_EL1 when cpu

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Message-Id: <20250804121724.3681531-6-yeoreum.yun@arm.com>
Date: Mon,  4 Aug 2025 13:17:18 +0100
From: Yeoreum Yun <yeoreum.yun@....com>
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	Yeoreum Yun <yeoreum.yun@....com>
Subject: [PATCH 05/11] arm64: save/restore SCTLR2_EL1 when cpu_suspend()/resume()

save/restore SCTLR2_EL1 when cpu_suspend()/resume().

Signed-off-by: Yeoreum Yun <yeoreum.yun@....com>
---
 arch/arm64/include/asm/suspend.h |  2 +-
 arch/arm64/mm/proc.S             | 26 ++++++++++++++++++--------
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/include/asm/suspend.h b/arch/arm64/include/asm/suspend.h
index 0cde2f473971..eb60c9735553 100644
--- a/arch/arm64/include/asm/suspend.h
+++ b/arch/arm64/include/asm/suspend.h
@@ -2,7 +2,7 @@
 #ifndef __ASM_SUSPEND_H
 #define __ASM_SUSPEND_H

-#define NR_CTX_REGS 13
+#define NR_CTX_REGS 14
 #define NR_CALLEE_SAVED_REGS 12

 /*
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 54dccfd6aa11..155d930b6d99 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -87,8 +87,14 @@ SYM_FUNC_START(cpu_do_suspend)
 	mrs	x9, mdscr_el1
 	mrs	x10, oslsr_el1
 	mrs	x11, sctlr_el1
-	get_this_cpu_offset x12
-	mrs	x13, sp_el0
+alternative_if_not ARM64_HAS_SCTLR2
+	mov	x12, xzr
+alternative_else
+	mrs_s	x12, SYS_SCTLR2_EL1
+alternative_endif
+	get_this_cpu_offset x13
+	mrs	x14, sp_el0
+
 	stp	x2, x3, [x0]
 	stp	x4, x5, [x0, #16]
 	stp	x6, x7, [x0, #32]
@@ -99,7 +105,7 @@ SYM_FUNC_START(cpu_do_suspend)
 	 * Save x18 as it may be used as a platform register, e.g. by shadow
 	 * call stack.
 	 */
-	str	x18, [x0, #96]
+	stp	x14, x18, [x0, #96]
 	ret
 SYM_FUNC_END(cpu_do_suspend)

@@ -120,8 +126,8 @@ SYM_FUNC_START(cpu_do_resume)
 	 * the buffer to minimize the risk of exposure when used for shadow
 	 * call stack.
 	 */
-	ldr	x18, [x0, #96]
-	str	xzr, [x0, #96]
+	ldp	x15, x18, [x0, #96]
+	str	xzr, [x0, #104]
 	msr	tpidr_el0, x2
 	msr	tpidrro_el0, x3
 	msr	contextidr_el1, x4
@@ -136,8 +142,12 @@ SYM_FUNC_START(cpu_do_resume)
 	msr	mdscr_el1, x10

 	msr	sctlr_el1, x12
-	set_this_cpu_offset x13
-	msr	sp_el0, x14
+alternative_if ARM64_HAS_SCTLR2
+	msr_s	SYS_SCTLR2_EL1, x13
+alternative_else_nop_endif
+
+	set_this_cpu_offset x14
+	msr	sp_el0, x15
 	/*
 	 * Restore oslsr_el1 by writing oslar_el1
 	 */
@@ -151,7 +161,7 @@ alternative_if ARM64_HAS_RAS_EXTN
 	msr_s	SYS_DISR_EL1, xzr
 alternative_else_nop_endif

-	ptrauth_keys_install_kernel_nosync x14, x1, x2, x3
+	ptrauth_keys_install_kernel_nosync x15, x1, x2, x3
 	isb
 	ret
 SYM_FUNC_END(cpu_do_resume)
--
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}