diff options
| -rw-r--r-- | arch/arm64/kernel/kaslr.c | 4 | ||||
| -rw-r--r-- | arch/arm64/mm/init.c | 22 |
2 files changed, 24 insertions, 2 deletions
diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c index 8b32a1f8f09f..582983920054 100644 --- a/arch/arm64/kernel/kaslr.c +++ b/arch/arm64/kernel/kaslr.c @@ -21,6 +21,7 @@ #include <asm/sections.h> u64 __read_mostly module_alloc_base; +u16 __initdata memstart_offset_seed; static __init u64 get_kaslr_seed(void *fdt) { @@ -123,6 +124,9 @@ u64 __init kaslr_early_init(u64 dt_phys) mask = ((1UL << (VA_BITS - 2)) - 1) & ~(SZ_2M - 1); offset = seed & mask; + /* use the top 16 bits to randomize the linear region */ + memstart_offset_seed = seed >> 48; + /* * The kernel Image should not extend across a 1GB/32MB/512MB alignment * boundary (for 4KB/16KB/64KB granule kernels, respectively). If this diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index c0ea54bd9995..e1f425fe5a81 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -196,6 +196,23 @@ void __init arm64_memblock_init(void) memblock_add(__pa(_text), (u64)(_end - _text)); } + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { + extern u16 memstart_offset_seed; + u64 range = linear_region_size - + (memblock_end_of_DRAM() - memblock_start_of_DRAM()); + + /* + * If the size of the linear region exceeds, by a sufficient + * margin, the size of the region that the available physical + * memory spans, randomize the linear region as well. + */ + if (memstart_offset_seed > 0 && range >= ARM64_MEMSTART_ALIGN) { + range = range / ARM64_MEMSTART_ALIGN + 1; + memstart_addr -= ARM64_MEMSTART_ALIGN * + ((range * memstart_offset_seed) >> 16); + } + } + /* * Register the kernel text, kernel data, initrd, and initial * pagetables with memblock. @@ -365,12 +382,13 @@ void __init mem_init(void) #ifdef CONFIG_SPARSEMEM_VMEMMAP MLG((unsigned long)vmemmap, (unsigned long)vmemmap + VMEMMAP_SIZE), - MLM((unsigned long)virt_to_page(PAGE_OFFSET), + MLM((unsigned long)phys_to_page(memblock_start_of_DRAM()), (unsigned long)virt_to_page(high_memory)), #endif MLK(FIXADDR_START, FIXADDR_TOP), MLM(PCI_IO_START, PCI_IO_END), - MLM(PAGE_OFFSET, (unsigned long)high_memory)); + MLM(__phys_to_virt(memblock_start_of_DRAM()), + (unsigned long)high_memory)); #undef MLK #undef MLM |