diff options
| author | Jiri Kosina <jkosina@suse.cz> | 2010-04-23 02:08:44 +0200 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.cz> | 2010-04-23 02:08:44 +0200 |
| commit | 6c9468e9eb1252eaefd94ce7f06e1be9b0b641b1 (patch) | |
| tree | 797676a336b050bfa1ef879377c07e541b9075d6 /arch/x86/mm/pageattr.c | |
| parent | 4cb3ca7cd7e2cae8d1daf5345ec99a1e8502cf3f (diff) | |
| parent | c81eddb0e3728661d1585fbc564449c94165cc36 (diff) | |
Merge branch 'master' into for-next
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)); |