diff options
| author | Arnd Bergmann <arnd@arndb.de> | 2012-10-04 22:57:00 +0200 |
|---|---|---|
| committer | Arnd Bergmann <arnd@arndb.de> | 2012-10-04 22:57:51 +0200 |
| commit | c37d6154c0b9163c27e53cc1d0be3867b4abd760 (patch) | |
| tree | 7a24522c56d1cb284dff1d3c225bbdaba0901bb5 /arch/x86/kernel/head_32.S | |
| parent | e7a570ff7dff9af6e54ff5e580a61ec7652137a0 (diff) | |
| parent | 8a1ab3155c2ac7fbe5f2038d6e26efeb607a1498 (diff) | |
Merge branch 'disintegrate-asm-generic' of git://git.infradead.org/users/dhowells/linux-headers into asm-generic
Patches from David Howells <dhowells@redhat.com>:
This is to complete part of the UAPI disintegration for which the
preparatory patches were pulled recently.
Note that there are some fixup patches which are at the base of the
branch aimed at you, plus all arches get the asm-generic branch merged in too.
* 'disintegrate-asm-generic' of git://git.infradead.org/users/dhowells/linux-headers:
UAPI: (Scripted) Disintegrate include/asm-generic
UAPI: Fix conditional header installation handling (notably kvm_para.h on m68k)
c6x: remove c6x signal.h
UAPI: Split compound conditionals containing __KERNEL__ in Arm64
UAPI: Fix the guards on various asm/unistd.h files
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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 d42ab17b739..957a47aec64 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 |