diff options
Diffstat (limited to 'arch/x86/mm/init_64.c')
| -rw-r--r-- | arch/x86/mm/init_64.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 76e33bd7c556..b9426fce5f3e 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -224,6 +224,24 @@ static void sync_global_pgds(unsigned long start, unsigned long end) } /* + * Make kernel mappings visible in all page tables in the system. + * This is necessary except when the init task populates kernel mappings + * during the boot process. In that case, all processes originating from + * the init task copies the kernel mappings, so there is no issue. + * Otherwise, missing synchronization could lead to kernel crashes due + * to missing page table entries for certain kernel mappings. + * + * Synchronization is performed at the top level, which is the PGD in + * 5-level paging systems. But in 4-level paging systems, however, + * pgd_populate() is a no-op, so synchronization is done at the P4D level. + * sync_global_pgds() handles this difference between paging levels. + */ +void arch_sync_kernel_mappings(unsigned long start, unsigned long end) +{ + sync_global_pgds(start, end); +} + +/* * NOTE: This function is marked __ref because it calls __init function * (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0. */ |