From: David Woodhouse <dwmw@amazon.co.uk>
Date: Sat, 25 Feb 2023 13:48:34 +0000 (+0000)
Subject: macro for realmode stack
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=refs%2Fheads%2Fparallel-6.2-rc8-brfirst;p=users%2Fdwmw2%2Flinux.git

macro for realmode stack
---

diff --git a/arch/x86/realmode/rm/trampoline_64.S b/arch/x86/realmode/rm/trampoline_64.S
index 49ebc1636ffde..da4ecf0fa9a84 100644
--- a/arch/x86/realmode/rm/trampoline_64.S
+++ b/arch/x86/realmode/rm/trampoline_64.S
@@ -37,6 +37,24 @@
 	.text
 	.code16
 
+.macro LOAD_REALMODE_ESP
+	/*
+         * Make sure only one CPU fiddles with the realmode stack
+         */
+.Llock_rm\@:
+	btl	$0, tr_lock
+	jnc	2f
+	pause
+	jmp	.Llock_rm\@
+2:
+	lock
+	btsl	$0, tr_lock
+	jc	.Llock_rm\@
+
+	# Setup stack
+	movl	$rm_stack_end, %esp
+.endm
+
 	.balign	PAGE_SIZE
 SYM_CODE_START(trampoline_start)
 	cli			# We should be safe anyway
@@ -49,21 +67,7 @@ SYM_CODE_START(trampoline_start)
 	mov	%ax, %es
 	mov	%ax, %ss
 
-	/*
-	 * Make sure only one CPU fiddles with the realmode stack
-	 */
-.Llock_rm:
-	btl	$0, tr_lock
-	jnc	2f
-	pause
-	jmp	.Llock_rm
-2:
-	lock
-	btsl	$0, tr_lock
-	jc	.Llock_rm
-
-	# Setup stack
-	movl	$rm_stack_end, %esp
+	LOAD_REALMODE_ESP
 
 	call	verify_cpu		# Verify the cpu supports long mode
 	testl   %eax, %eax		# Check for return code
@@ -106,8 +110,7 @@ SYM_CODE_START(sev_es_trampoline_start)
 	mov	%ax, %es
 	mov	%ax, %ss
 
-	# Setup stack
-	movl	$rm_stack_end, %esp
+	LOAD_REALMODE_ESP
 
 	jmp	.Lswitch_to_protected
 SYM_CODE_END(sev_es_trampoline_start)
@@ -190,7 +193,7 @@ SYM_CODE_START(pa_trampoline_compat)
 	 * In compatibility mode.  Prep ESP and DX for startup_32, then disable
 	 * paging and complete the switch to legacy 32-bit mode.
 	 */
-	movl	$rm_stack_end, %esp
+	LOAD_REALMODE_ESP
 	movw	$__KERNEL_DS, %dx
 
 	movl	$(CR0_STATE & ~X86_CR0_PG), %eax