diff options
Diffstat (limited to 'arch/arm64/kernel/head.S')
| -rw-r--r-- | arch/arm64/kernel/head.S | 59 |
1 files changed, 51 insertions, 8 deletions
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 4e69412a7323..319f896c6e74 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -210,6 +210,7 @@ section_table: ENTRY(stext) bl preserve_boot_args bl el2_setup // Drop to EL1, w20=cpu_boot_mode + mov x23, xzr // KASLR offset, defaults to 0 adrp x24, __PHYS_OFFSET bl set_cpu_boot_mode_flag bl __create_page_tables // x25=TTBR0, x26=TTBR1 @@ -313,7 +314,7 @@ ENDPROC(preserve_boot_args) __create_page_tables: adrp x25, idmap_pg_dir adrp x26, swapper_pg_dir - mov x27, lr + mov x28, lr /* * Invalidate the idmap and swapper page tables to avoid potential @@ -392,6 +393,7 @@ __create_page_tables: */ mov x0, x26 // swapper_pg_dir ldr x5, =KIMAGE_VADDR + add x5, x5, x23 // add KASLR displacement create_pgd_entry x0, x5, x3, x6 ldr w6, kernel_img_size add x6, x6, x5 @@ -408,8 +410,7 @@ __create_page_tables: dmb sy bl __inval_cache_range - mov lr, x27 - ret + ret x28 ENDPROC(__create_page_tables) kernel_img_size: @@ -421,6 +422,7 @@ kernel_img_size: */ .set initial_sp, init_thread_union + THREAD_START_SP __mmap_switched: + mov x28, lr // preserve LR adr_l x8, vectors // load VBAR_EL1 with virtual msr vbar_el1, x8 // vector table address isb @@ -449,19 +451,26 @@ __mmap_switched: ldr x13, [x9, #-8] cmp w12, #R_AARCH64_RELATIVE b.ne 1f - str x13, [x11] + add x13, x13, x23 // relocate + str x13, [x11, x23] b 0b 1: cmp w12, #R_AARCH64_ABS64 b.ne 0b add x12, x12, x12, lsl #1 // symtab offset: 24x top word add x12, x8, x12, lsr #(32 - 3) // ... shifted into bottom word + ldrsh w14, [x12, #6] // Elf64_Sym::st_shndx ldr x15, [x12, #8] // Elf64_Sym::st_value + cmp w14, #-0xf // SHN_ABS (0xfff1) ? + add x14, x15, x23 // relocate + csel x15, x14, x15, ne add x15, x13, x15 - str x15, [x11] + str x15, [x11, x23] b 0b -2: +2: adr_l x8, kimage_vaddr // make relocated kimage_vaddr + dc cvac, x8 // value visible to secondaries + dsb sy // with MMU off #endif adr_l sp, initial_sp, x4 @@ -470,7 +479,7 @@ __mmap_switched: msr sp_el0, x4 // Save thread_info str_l x21, __fdt_pointer, x5 // Save FDT pointer - ldr x4, =KIMAGE_VADDR // Save the offset between + ldr_l x4, kimage_vaddr // Save the offset between sub x4, x4, x24 // the kernel virtual and str_l x4, kimage_voffset, x5 // physical mappings @@ -478,6 +487,16 @@ __mmap_switched: #ifdef CONFIG_KASAN bl kasan_early_init #endif +#ifdef CONFIG_RANDOMIZE_BASE + cbnz x23, 0f // already running randomized? + mov x0, x21 // pass FDT address in x0 + bl kaslr_early_init // parse FDT for KASLR options + cbz x0, 0f // KASLR disabled? just proceed + mov x23, x0 // record KASLR offset + ret x28 // we must enable KASLR, return + // to __enable_mmu() +0: +#endif b start_kernel ENDPROC(__mmap_switched) @@ -486,6 +505,10 @@ ENDPROC(__mmap_switched) * hotplug and needs to have the same protections as the text region */ .section ".text","ax" + +ENTRY(kimage_vaddr) + .quad _text - TEXT_OFFSET + /* * If we're fortunate enough to boot at EL2, ensure that the world is * sane before dropping to EL1. @@ -651,7 +674,7 @@ ENTRY(secondary_startup) adrp x26, swapper_pg_dir bl __cpu_setup // initialise processor - ldr x8, =KIMAGE_VADDR + ldr x8, kimage_vaddr ldr w9, 0f sub x27, x8, w9, sxtw // address to jump to after enabling the MMU b __enable_mmu @@ -684,6 +707,7 @@ ENDPROC(__secondary_switched) */ .section ".idmap.text", "ax" __enable_mmu: + mrs x18, sctlr_el1 // preserve old SCTLR_EL1 value mrs x1, ID_AA64MMFR0_EL1 ubfx x2, x1, #ID_AA64MMFR0_TGRAN_SHIFT, 4 cmp x2, #ID_AA64MMFR0_TGRAN_SUPPORTED @@ -701,6 +725,25 @@ __enable_mmu: ic iallu dsb nsh isb +#ifdef CONFIG_RANDOMIZE_BASE + mov x19, x0 // preserve new SCTLR_EL1 value + blr x27 + + /* + * If we return here, we have a KASLR displacement in x23 which we need + * to take into account by discarding the current kernel mapping and + * creating a new one. + */ + msr sctlr_el1, x18 // disable the MMU + isb + bl __create_page_tables // recreate kernel mapping + + msr sctlr_el1, x19 // re-enable the MMU + isb + ic ialluis // flush instructions fetched + isb // via old mapping + add x27, x27, x23 // relocated __mmap_switched +#endif br x27 ENDPROC(__enable_mmu) |