From: Christian Hoffmann <chrmhoffmann@gmail.com>
Date: Tue, 7 Feb 2023 21:12:53 +0000 (+0100)
Subject: Revert "arm64: entry: Free up another register on kpti's tramp_exit path"
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=219164d083aace73f78b6bbb178785bf6ba42764;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

Revert "arm64: entry: Free up another register on kpti's tramp_exit path"

This reverts commit a212d166a9d7c35e56ba11f15d6706eee3dd499b.

Change-Id: If3cc91ff73fce3af22768516835a7050958571ed
---

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 8e00c6b4074a..a07d4ffb6465 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -311,9 +311,6 @@ alternative_else_nop_endif
 	ldp	x24, x25, [sp, #16 * 12]
 	ldp	x26, x27, [sp, #16 * 13]
 	ldp	x28, x29, [sp, #16 * 14]
-
-	.if	\el == 0
-alternative_if_not ARM64_UNMAP_KERNEL_AT_EL0
 	ldr	lr, [sp, #S_LR]
 #ifdef CONFIG_AMLOGIC_VMAP
 	/* restore context sp and per-cpu vmap stack */
@@ -328,11 +325,12 @@ alternative_if_not ARM64_UNMAP_KERNEL_AT_EL0
 	.endif
 #endif /* CONFIG_AMLOGIC_VMAP */
 	add	sp, sp, #S_FRAME_SIZE		// restore sp
-	eret
-alternative_else_nop_endif
+
+	.if	\el == 0
+alternative_insn eret, nop, ARM64_UNMAP_KERNEL_AT_EL0
 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
 	bne	4f
-	msr	far_el1, x29
+	msr	far_el1, x30
 	tramp_alias	x30, tramp_exit_native, x29
 	br	x30
 4:
@@ -340,8 +338,6 @@ alternative_else_nop_endif
 	br	x30
 #endif
 	.else
-	ldr	lr, [sp, #S_LR]
-	add	sp, sp, #S_FRAME_SIZE		// restore sp
 	eret
 	.endif
 	.endm
@@ -1185,12 +1181,10 @@ alternative_endif
 	ldr	x30, [x30, x29]
 
 	msr	vbar_el1, x30
-	ldr	lr, [sp, #S_LR]
-	tramp_unmap_kernel	x29
+	tramp_unmap_kernel	x30
 	.if	\regsize == 64
-	mrs	x29, far_el1
+	mrs	x30, far_el1
 	.endif
-	add	sp, sp, #S_FRAME_SIZE		// restore sp
 	eret
 	.endm