linux-kernel - [PATCH 12/23] x86, realmode: Remove indirect jumps in trampoline

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Date:	Tue,  8 May 2012 21:22:35 +0300
From:	Jarkko Sakkinen <jarkko.sakkinen@...el.com>
To:	linux-kernel@...r.kernel.org
Cc:	linux-kbuild@...r.kernel.org, Michal Marek <mmarek@...e.cz>,
	Sam Ravnborg <sam@...nborg.org>,
	Joseph Cihula <joseph.cihula@...el.com>,
	Shane Wang <shane.wang@...el.com>, hpa@...ux.intel.com
Subject: [PATCH 12/23] x86, realmode: Remove indirect jumps in trampoline_64.S

From: "H. Peter Anvin" <hpa@...ux.intel.com>

Remove indirect jumps in trampoline_64.S which are no longer
necessary: the realmode code can relocate the absolute jumps
correctly from the start.

Signed-off-by: H. Peter Anvin <hpa@...ux.intel.com>
---
 arch/x86/realmode/rm/trampoline_64.S |   15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)

diff --git a/arch/x86/realmode/rm/trampoline_64.S b/arch/x86/realmode/rm/trampoline_64.S
index 66c58cf..77b72b4 100644
--- a/arch/x86/realmode/rm/trampoline_64.S
+++ b/arch/x86/realmode/rm/trampoline_64.S
@@ -73,7 +73,7 @@ ENTRY(trampoline_data)
 	lmsw	%ax			# into protected mode
 
 	# flush prefetch and jump to startup_32
-	ljmpl	*(startup_32_vector)
+	ljmpl	$__KERNEL32_CS, $pa_startup_32
 
 no_longmode:
 	hlt
@@ -113,7 +113,7 @@ ENTRY(startup_32)
 	 * EFER.LMA = 1). Now we want to jump in 64bit mode, to do that we use
 	 * the new gdt/idt that has __KERNEL_CS with CS.L = 1.
 	 */
-	ljmpl	*(pa_startup_64_vector)
+	ljmpl	$__KERNEL_CS, $pa_startup_64
 
 	.section ".text64","ax"
 	.code64
@@ -144,17 +144,6 @@ tgdt:
 	.quad	0x00cf93000000ffff	# __KERNEL_DS
 tgdt_end:
 
-	.balign 4
-startup_32_vector:
-	.long	pa_startup_32
-	.word	__KERNEL32_CS, 0
-
-	.balign 4
-	.globl startup_64_vector
-startup_64_vector:
-	.long	pa_startup_64
-	.word	__KERNEL_CS, 0
-
 	.data
 	.balign 4
 GLOBAL(trampoline_status)
-- 
1.7.9.5

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