linux-kernel - [PATCH v2 09/15] x86/entry_32: Convert X86_INVD

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Date:	Tue, 24 Feb 2015 12:14:51 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	X86 ML <x86@...nel.org>
Cc:	Andy Lutomirski <luto@...capital.net>,
	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH v2 09/15] x86/entry_32: Convert X86_INVD_BUG to ALTERNATIVE macro

From: Borislav Petkov <bp@...e.de>

Booting a 486 kernel on an AMD guest with this patch applied, says:

  apply_alternatives: feat: 0*32+25, old: (c160a475, len: 5), repl: (c19557d4, len: 5)
  c160a475: alt_insn: 68 10 35 00 c1
  c19557d4: rpl_insn: 68 80 39 00 c1

which is:

  old insn VA: 0xc160a475, CPU feat: X86_FEATURE_XMM, size: 5
  simd_coprocessor_error:
           c160a475:      68 10 35 00 c1          push $0xc1003510 <do_general_protection>
  repl insn: 0xc19557d4, size: 5
           c160a475:      68 80 39 00 c1          push $0xc1003980 <do_simd_coprocessor_error>

Signed-off-by: Borislav Petkov <bp@...e.de>
---
 arch/x86/kernel/entry_32.S | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index d23c9a1d40e1..b910577d1ff9 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -816,15 +816,9 @@ ENTRY(simd_coprocessor_error)
 	pushl_cfi $0
 #ifdef CONFIG_X86_INVD_BUG
 	/* AMD 486 bug: invd from userspace calls exception 19 instead of #GP */
-661:	pushl_cfi $do_general_protection
-662:
-.section .altinstructions,"a"
-	altinstruction_entry 661b, 663f, X86_FEATURE_XMM, 662b-661b, 664f-663f, 0
-.previous
-.section .altinstr_replacement,"ax"
-663:	pushl $do_simd_coprocessor_error
-664:
-.previous
+	ALTERNATIVE "pushl_cfi $do_general_protection",	\
+		    "pushl $do_simd_coprocessor_error", \
+		    X86_FEATURE_XMM
 #else
 	pushl_cfi $do_simd_coprocessor_error
 #endif
-- 
2.2.0.33.gc18b867

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