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| author | Dave Hansen <dave.hansen@linux.intel.com> | 2017-12-04 15:07:39 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-12-23 21:13:00 +0100 |
| commit | d9e9a6418065bb376e5de8d93ce346939b9a37a6 (patch) | |
| tree | 202972fb21b78383a906dc20ebc17798e8aa0a7d /arch/x86/include/asm/pgalloc.h | |
| parent | 1c4de1ff4fe50453b968579ee86fac3da80dd783 (diff) | |
| download | linux-0-day-d9e9a6418065bb376e5de8d93ce346939b9a37a6.tar.gz linux-0-day-d9e9a6418065bb376e5de8d93ce346939b9a37a6.tar.xz | |
x86/mm/pti: Allocate a separate user PGD
Kernel page table isolation requires to have two PGDs. One for the kernel,
which contains the full kernel mapping plus the user space mapping and one
for user space which contains the user space mappings and the minimal set
of kernel mappings which are required by the architecture to be able to
transition from and to user space.
Add the necessary preliminaries.
[ tglx: Split out from the big kaiser dump. EFI fixup from Kirill ]
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.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 4b5e1eafada73..aff42e1da6ee1 100644 --- a/arch/x86/include/asm/pgalloc.h +++ b/arch/x86/include/asm/pgalloc.h @@ -30,6 +30,17 @@ static inline void paravirt_release_p4d(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. */ |