diff options
| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2012-10-11 10:55:04 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2012-10-11 10:55:04 +0100 |
| commit | a0f0dd57f4a85310d9936f1770a0424b49fef876 (patch) | |
| tree | 2f85b8b67dda13d19b02ca39e0fbef921cb1cf8b /arch/x86/kernel/head_32.S | |
| parent | 2a552d5e63d7fa602c9a9a0717008737f55625a6 (diff) | |
| parent | 846a136881b8f73c1f74250bf6acfaa309cab1f2 (diff) | |
Merge branch 'fixes' into for-linus
Conflicts:
arch/arm/kernel/smp.c
Diffstat (limited to 'arch/x86/kernel/head_32.S')
| -rw-r--r-- | arch/x86/kernel/head_32.S | 31 |
1 files changed, 16 insertions, 15 deletions
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index d42ab17b7397..957a47aec64e 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -287,27 +287,28 @@ ENTRY(startup_32_smp) leal -__PAGE_OFFSET(%ecx),%esp default_entry: - /* * New page tables may be in 4Mbyte page mode and may * be using the global pages. * * NOTE! If we are on a 486 we may have no cr4 at all! - * So we do not try to touch it unless we really have - * some bits in it to set. This won't work if the BSP - * implements cr4 but this AP does not -- very unlikely - * but be warned! The same applies to the pse feature - * if not equally supported. --macro - * - * NOTE! We have to correct for the fact that we're - * not yet offset PAGE_OFFSET.. + * Specifically, cr4 exists if and only if CPUID exists, + * which in turn exists if and only if EFLAGS.ID exists. */ -#define cr4_bits pa(mmu_cr4_features) - movl cr4_bits,%edx - andl %edx,%edx - jz 6f - movl %cr4,%eax # Turn on paging options (PSE,PAE,..) - orl %edx,%eax + movl $X86_EFLAGS_ID,%ecx + pushl %ecx + popfl + pushfl + popl %eax + pushl $0 + popfl + pushfl + popl %edx + xorl %edx,%eax + testl %ecx,%eax + jz 6f # No ID flag = no CPUID = no CR4 + + movl pa(mmu_cr4_features),%eax movl %eax,%cr4 testb $X86_CR4_PAE, %al # check if PAE is enabled |