diff options
| -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(); } |