diff options
| author | Andy Lutomirski <luto@kernel.org> | 2016-05-10 14:10:29 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-05-20 09:10:03 +0200 |
| commit | dc4fac84f8e66b147921ebdc385e767d5def7422 (patch) | |
| tree | 7867ab702abfe0cc1cfb39acd99e18a259812849 /arch/x86/mm | |
| parent | d696ca016d579d43fc043f28ba656d9305fba651 (diff) | |
x86/mm: Switch from TASK_SIZE to TASK_SIZE_MAX in the page fault code
x86's page fault handlers had two TASK_SIZE uses that should have
been TASK_SIZE_MAX. I don't think that either one had a visible
effect, but this makes the code clearer and should save a few bytes
of text.
(And I eventually want to eradicate TASK_SIZE. This will help.)
Reported-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ruslan Kabatsayev <b7.10110111@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1242fb23b0d05c3069dbf5758ac55d26bc114bef.1462914565.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/mm')
| -rw-r--r-- | arch/x86/mm/fault.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 5ce1ed02f7e8..7d1fa7cd2374 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -292,7 +292,7 @@ void vmalloc_sync_all(void) return; for (address = VMALLOC_START & PMD_MASK; - address >= TASK_SIZE && address < FIXADDR_TOP; + address >= TASK_SIZE_MAX && address < FIXADDR_TOP; address += PMD_SIZE) { struct page *page; @@ -854,8 +854,13 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code, return; } #endif - /* Kernel addresses are always protection faults: */ - if (address >= TASK_SIZE) + + /* + * To avoid leaking information about the kernel page table + * layout, pretend that user-mode accesses to kernel addresses + * are always protection faults. + */ + if (address >= TASK_SIZE_MAX) error_code |= PF_PROT; if (likely(show_unhandled_signals)) |