diff options
| -rw-r--r-- | arch/x86/boot/compressed/pagetable.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/arch/x86/boot/compressed/pagetable.c b/arch/x86/boot/compressed/pagetable.c index 8e69df96492e..28029be47fbb 100644 --- a/arch/x86/boot/compressed/pagetable.c +++ b/arch/x86/boot/compressed/pagetable.c @@ -63,7 +63,7 @@ static void *alloc_pgt_page(void *context) static struct alloc_pgt_data pgt_data; /* The top level page table entry pointer. */ -static unsigned long level4p; +static unsigned long top_level_pgt; /* * Mapping information structure passed to kernel_ident_mapping_init(). @@ -91,9 +91,15 @@ void initialize_identity_maps(void) * If we came here via startup_32(), cr3 will be _pgtable already * and we must append to the existing area instead of entirely * overwriting it. + * + * With 5-level paging, we use '_pgtable' to allocate the p4d page table, + * the top-level page table is allocated separately. + * + * p4d_offset(top_level_pgt, 0) would cover both the 4- and 5-level + * cases. On 4-level paging it's equal to 'top_level_pgt'. */ - level4p = read_cr3_pa(); - if (level4p == (unsigned long)_pgtable) { + top_level_pgt = read_cr3_pa(); + if (p4d_offset((pgd_t *)top_level_pgt, 0) == (p4d_t *)_pgtable) { debug_putstr("booted via startup_32()\n"); pgt_data.pgt_buf = _pgtable + BOOT_INIT_PGT_SIZE; pgt_data.pgt_buf_size = BOOT_PGT_SIZE - BOOT_INIT_PGT_SIZE; @@ -103,7 +109,7 @@ void initialize_identity_maps(void) pgt_data.pgt_buf = _pgtable; pgt_data.pgt_buf_size = BOOT_PGT_SIZE; memset(pgt_data.pgt_buf, 0, pgt_data.pgt_buf_size); - level4p = (unsigned long)alloc_pgt_page(&pgt_data); + top_level_pgt = (unsigned long)alloc_pgt_page(&pgt_data); } } @@ -123,7 +129,7 @@ void add_identity_map(unsigned long start, unsigned long size) return; /* Build the mapping. */ - kernel_ident_mapping_init(&mapping_info, (pgd_t *)level4p, + kernel_ident_mapping_init(&mapping_info, (pgd_t *)top_level_pgt, start, end); } @@ -134,5 +140,5 @@ void add_identity_map(unsigned long start, unsigned long size) */ void finalize_identity_maps(void) { - write_cr3(level4p); + write_cr3(top_level_pgt); } |