diff options
| author | Pavel Tatashin <pasha.tatashin@oracle.com> | 2018-01-15 19:44:14 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-17 11:39:00 +0300 |
| commit | 1b92c48a2eeb8e4c77a27c93052ba95dc6e1cdda (patch) | |
| tree | 151dcd613c9f071b88260ce155ea3348fd784e85 /arch/x86/include/asm/pgalloc.h | |
| parent | 92e8f204947484f642b77836c0ce9f710d83f836 (diff) | |
| download | linux-1b92c48a2eeb8e4c77a27c93052ba95dc6e1cdda.tar.xz | |
x86/pti/efi: broken conversion from efi to kernel page table
The page table order must be increased for EFI table in order to avoid a
bug where NMI tries to change the page table to kernel page table, while
efi page table is active.
For more disccussion about this bug, see this thread:
http://lkml.iu.edu/hypermail/linux/kernel/1801.1/00951.html
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/include/asm/pgalloc.h')
| -rw-r--r-- | arch/x86/include/asm/pgalloc.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/include/asm/pgalloc.h b/arch/x86/include/asm/pgalloc.h index b6d425999f99..1178a51b77f3 100644 --- a/arch/x86/include/asm/pgalloc.h +++ b/arch/x86/include/asm/pgalloc.h @@ -27,6 +27,17 @@ static inline void paravirt_release_pud(unsigned long pfn) {} */ extern gfp_t __userpte_alloc_gfp; +#ifdef CONFIG_PAGE_TABLE_ISOLATION +/* + * Instead of one PGD, we acquire two PGDs. Being order-1, it is + * both 8k in size and 8k-aligned. That lets us just flip bit 12 + * in a pointer to swap between the two 4k halves. + */ +#define PGD_ALLOCATION_ORDER 1 +#else +#define PGD_ALLOCATION_ORDER 0 +#endif + /* * Allocate and free page tables. */ |