diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/boot/compressed/kaslr.c | 3 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/misc.h | 3 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/pagetable.c | 26 |
3 files changed, 22 insertions, 10 deletions
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index dff42177cb0c..54037c9f2def 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -478,6 +478,9 @@ unsigned char *choose_random_location(unsigned long input, boot_params->hdr.loadflags |= KASLR_FLAG; + /* Prepare to add new identity pagetables on demand. */ + initialize_identity_maps(); + /* Record the various known unsafe memory ranges. */ mem_avoid_init(input, input_size, output); diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index b6fec1ff10e4..09c4ddd02ac6 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -85,10 +85,13 @@ unsigned char *choose_random_location(unsigned long input_ptr, #endif #ifdef CONFIG_X86_64 +void initialize_identity_maps(void); void add_identity_map(unsigned long start, unsigned long size); void finalize_identity_maps(void); extern unsigned char _pgtable[]; #else +static inline void initialize_identity_maps(void) +{ } static inline void add_identity_map(unsigned long start, unsigned long size) { } static inline void finalize_identity_maps(void) diff --git a/arch/x86/boot/compressed/pagetable.c b/arch/x86/boot/compressed/pagetable.c index 34b95df14e69..6e31a6aac4d3 100644 --- a/arch/x86/boot/compressed/pagetable.c +++ b/arch/x86/boot/compressed/pagetable.c @@ -2,6 +2,9 @@ * This code is used on x86_64 to create page table identity mappings on * demand by building up a new set of page tables (or appending to the * existing ones), and then switching over to them when ready. + * + * Copyright (C) 2015-2016 Yinghai Lu + * Copyright (C) 2016 Kees Cook */ /* @@ -59,9 +62,21 @@ static struct alloc_pgt_data pgt_data; /* The top level page table entry pointer. */ static unsigned long level4p; +/* + * Mapping information structure passed to kernel_ident_mapping_init(). + * Due to relocation, pointers must be assigned at run time not build time. + */ +static struct x86_mapping_info mapping_info = { + .pmd_flag = __PAGE_KERNEL_LARGE_EXEC, +}; + /* Locates and clears a region for a new top level page table. */ -static void prepare_level4(void) +void initialize_identity_maps(void) { + /* Init mapping_info with run-time function/buffer pointers. */ + mapping_info.alloc_pgt_page = alloc_pgt_page; + mapping_info.context = &pgt_data; + /* * It should be impossible for this not to already be true, * but since calling this a second time would rewind the other @@ -96,17 +111,8 @@ static void prepare_level4(void) */ void add_identity_map(unsigned long start, unsigned long size) { - struct x86_mapping_info mapping_info = { - .alloc_pgt_page = alloc_pgt_page, - .context = &pgt_data, - .pmd_flag = __PAGE_KERNEL_LARGE_EXEC, - }; unsigned long end = start + size; - /* Make sure we have a top level page table ready to use. */ - if (!level4p) - prepare_level4(); - /* Align boundary to 2M. */ start = round_down(start, PMD_SIZE); end = round_up(end, PMD_SIZE); |