From: Borislav Petkov <bp@alien8.de>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: X86 ML <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
Borislav Petkov <bp@suse.de>
Subject: [PATCH 1/4] x86, head_32: Remove i386 pieces
Date: Mon, 11 Feb 2013 15:22:15 +0100 [thread overview]
Message-ID: <1360592538-10643-2-git-send-email-bp@alien8.de> (raw)
In-Reply-To: <1360592538-10643-1-git-send-email-bp@alien8.de>
From: Borislav Petkov <bp@suse.de>
Remove code fragments detecting a 386 CPU since we don't support those
anymore. Also, do not do alignment checks because they're done only at
CPL3. Also, no need to preserve EFLAGS.
Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/kernel/head_32.S | 22 +++++-----------------
1 file changed, 5 insertions(+), 17 deletions(-)
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index 0b8c825fc264..f4d919e2cd2b 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -405,30 +405,21 @@ default_entry:
jz 1f # Did we do this already?
call *%eax
1:
-
-/* check if it is 486 or 386. */
+
/*
- * XXX - this does a lot of unnecessary setup. Alignment checks don't
- * apply at our cpl of 0 and the stack ought to be aligned already, and
- * we don't need to preserve eflags.
+ * Check if it is 486
*/
movl $-1,X86_CPUID # -1 for no CPUID initially
- movb $3,X86 # at least 386
+ movb $4,X86 # at least 486
pushfl # push EFLAGS
popl %eax # get EFLAGS
movl %eax,%ecx # save original EFLAGS
- xorl $0x240000,%eax # flip AC and ID bits in EFLAGS
+ xorl $0x200000,%eax # flip ID bit in EFLAGS
pushl %eax # copy to EFLAGS
popfl # set EFLAGS
pushfl # get new EFLAGS
popl %eax # put it in eax
xorl %ecx,%eax # change in flags
- pushl %ecx # restore original EFLAGS
- popfl
- testl $0x40000,%eax # check if AC bit changed
- je is386
-
- movb $4,X86 # at least 486
testl $0x200000,%eax # check if ID bit changed
je is486
@@ -456,10 +447,7 @@ default_entry:
movl %edx,X86_CAPABILITY
is486: movl $0x50022,%ecx # set AM, WP, NE and MP
- jmp 2f
-
-is386: movl $2,%ecx # set MP
-2: movl %cr0,%eax
+ movl %cr0,%eax
andl $0x80000011,%eax # Save PG,PE,ET
orl %ecx,%eax
movl %eax,%cr0
--
1.8.1.3.535.ga923c31
next prev parent reply other threads:[~2013-02-11 14:22 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-11 14:22 [PATCH 0/4 -v3] x86, head_32: Some cleanups Borislav Petkov
2013-02-11 14:22 ` Borislav Petkov [this message]
2013-02-13 0:07 ` [tip:x86/asm] x86, head_32: Remove i386 pieces tip-bot for Borislav Petkov
2013-02-11 14:22 ` [PATCH 2/4] x86: Detect CPUID support early at boot Borislav Petkov
2013-02-13 0:09 ` [tip:x86/asm] " tip-bot for Borislav Petkov
2013-02-11 14:22 ` [PATCH 3/4] x86, head_32: Remove second CPUID detection from default_entry Borislav Petkov
2013-02-11 15:49 ` H. Peter Anvin
2013-02-11 17:15 ` Borislav Petkov
2013-02-11 17:21 ` H. Peter Anvin
2013-02-13 0:10 ` [tip:x86/asm] " tip-bot for Borislav Petkov
2013-02-11 14:22 ` [PATCH 4/4] x86, head_32: Give the 6 label a real name Borislav Petkov
2013-02-13 0:11 ` [tip:x86/asm] " tip-bot for Borislav Petkov
2013-02-11 16:56 ` [PATCH 0/4 -v3] x86, head_32: Some cleanups H. Peter Anvin
-- strict thread matches above, loose matches on Subject: below --
2013-02-03 16:14 [PATCH 0/4] " Borislav Petkov
2013-02-03 16:14 ` [PATCH 1/4] x86, head_32: Remove i386 pieces Borislav Petkov
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