From: Thomas Gleixner <t...@linutronix.de> PAGE_NX and PAGE_GLOBAL might not be supported, or migth be disabled on the command line, but Kaiser sets them unconditionally.
Add proper protection against that. Signed-off-by: Thomas Gleixner <t...@linutronix.de> Cc: Andy Lutomirski <l...@kernel.org> Cc: Borislav Petkov <b...@alien8.de> Cc: Brian Gerst <brge...@gmail.com> Cc: Dave Hansen <dave.han...@linux.intel.com> Cc: Denys Vlasenko <dvlas...@redhat.com> Cc: Josh Poimboeuf <jpoim...@redhat.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Rik van Riel <r...@redhat.com> Cc: daniel.gr...@iaik.tugraz.at Cc: hu...@google.com Cc: keesc...@google.com Cc: linux...@kvack.org Cc: michael.schw...@iaik.tugraz.at Cc: moritz.l...@iaik.tugraz.at Cc: richard.fell...@student.tugraz.at Link: http://lkml.kernel.org/r/20171126232414.313869...@linutronix.de Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/x86/include/asm/pgtable_64.h | 3 ++- arch/x86/mm/kaiser.c | 12 +++++++++++- 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h index 0c6e14f1e274..1c9f1f803ad8 100644 --- a/arch/x86/include/asm/pgtable_64.h +++ b/arch/x86/include/asm/pgtable_64.h @@ -222,7 +222,8 @@ static inline pgd_t kaiser_set_shadow_pgd(pgd_t *pgdp, pgd_t pgd) * wrong CR3 value, userspace will crash * instead of running. */ - pgd.pgd |= _PAGE_NX; + if (__supported_pte_mask & _PAGE_NX) + pgd.pgd |= _PAGE_NX; } } else if (pgd_userspace_access(*pgdp)) { /* diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c index 10c0e9e6bf6b..6e3c5da5f7e8 100644 --- a/arch/x86/mm/kaiser.c +++ b/arch/x86/mm/kaiser.c @@ -42,6 +42,8 @@ #define KAISER_WALK_ATOMIC 0x1 +static pteval_t kaiser_pte_mask __ro_after_init = ~(_PAGE_NX | _PAGE_GLOBAL); + /* * At runtime, the only things we map are some things for CPU * hotplug, and stacks for new processes. No two CPUs will ever @@ -244,11 +246,14 @@ static pte_t *kaiser_shadow_pagetable_walk(unsigned long address, int kaiser_add_user_map(const void *__start_addr, unsigned long size, unsigned long flags) { - pte_t *pte; unsigned long start_addr = (unsigned long)__start_addr; unsigned long address = start_addr & PAGE_MASK; unsigned long end_addr = PAGE_ALIGN(start_addr + size); unsigned long target_address; + pte_t *pte; + + /* Clear not supported bits */ + flags &= kaiser_pte_mask; for (; address < end_addr; address += PAGE_SIZE) { target_address = get_pa_from_kernel_map(address); @@ -308,6 +313,11 @@ static void __init kaiser_init_all_pgds(void) pgd_t *pgd; int i; + if (__supported_pte_mask & _PAGE_NX) + kaiser_pte_mask |= _PAGE_NX; + if (boot_cpu_has(X86_FEATURE_PGE)) + kaiser_pte_mask |= _PAGE_GLOBAL; + pgd = kernel_to_shadow_pgdp(pgd_offset_k(0UL)); for (i = PTRS_PER_PGD / 2; i < PTRS_PER_PGD; i++) { /* -- 2.14.1
