diff options
| author | Ingo Molnar <mingo@elte.hu> | 2010-05-03 09:17:01 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-05-03 09:17:01 +0200 |
| commit | 53ba4f2fa73225113a488584df0d85d3cba52943 (patch) | |
| tree | d85b984d9818abc3ccc0237eb53b710d9e96c39e /arch/x86/mm/pageattr.c | |
| parent | bd6d29c25bb1a24a4c160ec5de43e0004e01f72b (diff) | |
| parent | 66f41d4c5c8a5deed66fdcc84509376c9a0bf9d8 (diff) | |
Merge commit 'v2.6.34-rc6' into core/locking
Diffstat (limited to 'arch/x86/mm/pageattr.c')
| -rw-r--r-- | arch/x86/mm/pageattr.c | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 1d4eb93d333..28195c350b9 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -6,13 +6,13 @@ #include <linux/bootmem.h> #include <linux/module.h> #include <linux/sched.h> -#include <linux/slab.h> #include <linux/mm.h> #include <linux/interrupt.h> #include <linux/seq_file.h> #include <linux/debugfs.h> #include <linux/pfn.h> #include <linux/percpu.h> +#include <linux/gfp.h> #include <asm/e820.h> #include <asm/processor.h> @@ -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)); |