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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-03-13 14:45:49 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-03-13 14:45:49 -0800 |
| commit | 15c989d4d14b82f43cae7efc6a7794cdd556f274 (patch) | |
| tree | 3f1a22991aacf42acaf56467cbe79897146d3e32 /arch/x86/mm | |
| parent | 4e3eaddd142e2142c048c5052a0a9d2604fccfc6 (diff) | |
| parent | 0e152cd7c16832bd5cadee0c2e41d9959bc9b6f9 (diff) | |
Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, k8 nb: Fix boot crash: enable k8_northbridges unconditionally on AMD systems
x86, UV: Fix target_cpus() in x2apic_uv_x.c
x86: Reduce per cpu warning boot up messages
x86: Reduce per cpu MCA boot up messages
x86_64, cpa: Don't work hard in preserving kernel 2M mappings when using 4K already
Diffstat (limited to 'arch/x86/mm')
| -rw-r--r-- | arch/x86/mm/pageattr.c | 25 |
1 files changed, 23 insertions, 2 deletions
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 1d4eb93d333c..cf07c26d9a4a 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -291,8 +291,29 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address, */ if (kernel_set_to_readonly && within(address, (unsigned long)_text, - (unsigned long)__end_rodata_hpage_align)) - pgprot_val(forbidden) |= _PAGE_RW; + (unsigned long)__end_rodata_hpage_align)) { + unsigned int level; + + /* + * Don't enforce the !RW mapping for the kernel text mapping, + * if the current mapping is already using small page mapping. + * No need to work hard to preserve large page mappings in this + * case. + * + * This also fixes the Linux Xen paravirt guest boot failure + * (because of unexpected read-only mappings for kernel identity + * mappings). In this paravirt guest case, the kernel text + * mapping and the kernel identity mapping share the same + * page-table pages. Thus we can't really use different + * protections for the kernel text and identity mappings. Also, + * these shared mappings are made of small page mappings. + * Thus this don't enforce !RW mapping for small page kernel + * text mapping logic will help Linux Xen parvirt guest boot + * aswell. + */ + if (lookup_address(address, &level) && (level != PG_LEVEL_4K)) + pgprot_val(forbidden) |= _PAGE_RW; + } #endif prot = __pgprot(pgprot_val(prot) & ~pgprot_val(forbidden)); |