diff options
| author | Andy Lutomirski <luto@kernel.org> | 2017-12-04 15:07:45 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-12-23 21:13:00 +0100 |
| commit | f7cfbee91559ca7e3e961a00ffac921208a115ad (patch) | |
| tree | 5057b5b52baccddbe6dd47b8a662305c1fda4c90 /arch | |
| parent | x86/mm/pti: Force entry through trampoline when PTI active (diff) | |
| download | linux-f7cfbee91559ca7e3e961a00ffac921208a115ad.tar.xz linux-f7cfbee91559ca7e3e961a00ffac921208a115ad.zip | |
x86/mm/pti: Share cpu_entry_area with user space page tables
Share the cpu entry area so the user space and kernel space page tables
have the same P4D page.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.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')
| -rw-r--r-- | arch/x86/mm/pti.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index d58bcee470fc..59290356f19f 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -265,6 +265,29 @@ pti_clone_pmds(unsigned long start, unsigned long end, pmdval_t clear) } /* + * Clone a single p4d (i.e. a top-level entry on 4-level systems and a + * next-level entry on 5-level systems. + */ +static void __init pti_clone_p4d(unsigned long addr) +{ + p4d_t *kernel_p4d, *user_p4d; + pgd_t *kernel_pgd; + + user_p4d = pti_user_pagetable_walk_p4d(addr); + kernel_pgd = pgd_offset_k(addr); + kernel_p4d = p4d_offset(kernel_pgd, addr); + *user_p4d = *kernel_p4d; +} + +/* + * Clone the CPU_ENTRY_AREA into the user space visible page table. + */ +static void __init pti_clone_user_shared(void) +{ + pti_clone_p4d(CPU_ENTRY_AREA_BASE); +} + +/* * Initialize kernel page table isolation */ void __init pti_init(void) @@ -273,4 +296,6 @@ void __init pti_init(void) return; pr_info("enabled\n"); + + pti_clone_user_shared(); } |