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yaml
---
r: 173046
b: refs/heads/master
c: 8a50e51
h: refs/heads/master
v: v3
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H. Peter Anvin committed Nov 16, 2009
1 parent d949065 commit 30d3746
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Showing 2 changed files with 12 additions and 8 deletions.
2 changes: 1 addition & 1 deletion [refs]
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@@ -1,2 +1,2 @@
---
refs/heads/master: 196cf0d67acad70ebb2572da489d5cc7066cdd05
refs/heads/master: 8a50e5135af0c243e117e94e27feb8d149c879b4
18 changes: 11 additions & 7 deletions trunk/arch/x86/kernel/head_32.S
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Expand Up @@ -18,6 +18,8 @@
#include <asm/asm-offsets.h>
#include <asm/setup.h>
#include <asm/processor-flags.h>
#include <asm/msr-index.h>
#include <asm/cpufeature.h>
#include <asm/percpu.h>

/* Physical address */
Expand Down Expand Up @@ -297,25 +299,27 @@ ENTRY(startup_32_smp)
orl %edx,%eax
movl %eax,%cr4

btl $5, %eax # check if PAE is enabled
jnc 6f
testb $X86_CR4_PAE, %al # check if PAE is enabled
jz 6f

/* Check if extended functions are implemented */
movl $0x80000000, %eax
cpuid
cmpl $0x80000000, %eax
jbe 6f
/* Value must be in the range 0x80000001 to 0x8000ffff */
subl $0x80000001, %eax
cmpl $(0x8000ffff-0x80000001), %eax
ja 6f
mov $0x80000001, %eax
cpuid
/* Execute Disable bit supported? */
btl $20, %edx
btl $(X86_FEATURE_NX & 31), %edx
jnc 6f

/* Setup EFER (Extended Feature Enable Register) */
movl $0xc0000080, %ecx
movl $MSR_EFER, %ecx
rdmsr

btsl $11, %eax
btsl $_EFER_NX, %eax
/* Make changes effective */
wrmsr

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