diff options
Diffstat (limited to 'arch/arm64/kernel/head.S')
| -rw-r--r-- | arch/arm64/kernel/head.S | 229 |
1 files changed, 175 insertions, 54 deletions
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index d019c3a58cc2..23cf8e9a295f 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -25,15 +25,18 @@ #include <linux/irqchip/arm-gic-v3.h> #include <asm/assembler.h> +#include <asm/boot.h> #include <asm/ptrace.h> #include <asm/asm-offsets.h> #include <asm/cache.h> #include <asm/cputype.h> +#include <asm/elf.h> #include <asm/kernel-pgtable.h> #include <asm/memory.h> #include <asm/pgtable-hwdef.h> #include <asm/pgtable.h> #include <asm/page.h> +#include <asm/smp.h> #include <asm/sysreg.h> #include <asm/thread_info.h> #include <asm/virt.h> @@ -48,9 +51,6 @@ #error TEXT_OFFSET must be less than 2MB #endif -#define KERNEL_START _text -#define KERNEL_END _end - /* * Kernel startup entry point. * --------------------------- @@ -67,12 +67,11 @@ * in the entry routines. */ __HEAD - +_head: /* * DO NOT MODIFY. Image header expected by Linux boot-loaders. */ #ifdef CONFIG_EFI -efi_head: /* * This add instruction has no meaningful effect except that * its opcode forms the magic "MZ" signature required by UEFI. @@ -83,9 +82,9 @@ efi_head: b stext // branch to kernel start, magic .long 0 // reserved #endif - .quad _kernel_offset_le // Image load offset from start of RAM, little-endian - .quad _kernel_size_le // Effective size of kernel image, little-endian - .quad _kernel_flags_le // Informative flags, little-endian + le64sym _kernel_offset_le // Image load offset from start of RAM, little-endian + le64sym _kernel_size_le // Effective size of kernel image, little-endian + le64sym _kernel_flags_le // Informative flags, little-endian .quad 0 // reserved .quad 0 // reserved .quad 0 // reserved @@ -94,14 +93,12 @@ efi_head: .byte 0x4d .byte 0x64 #ifdef CONFIG_EFI - .long pe_header - efi_head // Offset to the PE header. + .long pe_header - _head // Offset to the PE header. #else .word 0 // reserved #endif #ifdef CONFIG_EFI - .globl __efistub_stext_offset - .set __efistub_stext_offset, stext - efi_head .align 3 pe_header: .ascii "PE" @@ -121,11 +118,11 @@ optional_header: .short 0x20b // PE32+ format .byte 0x02 // MajorLinkerVersion .byte 0x14 // MinorLinkerVersion - .long _end - stext // SizeOfCode + .long _end - efi_header_end // SizeOfCode .long 0 // SizeOfInitializedData .long 0 // SizeOfUninitializedData - .long __efistub_entry - efi_head // AddressOfEntryPoint - .long __efistub_stext_offset // BaseOfCode + .long __efistub_entry - _head // AddressOfEntryPoint + .long efi_header_end - _head // BaseOfCode extra_header_fields: .quad 0 // ImageBase @@ -139,10 +136,10 @@ extra_header_fields: .short 0 // MinorSubsystemVersion .long 0 // Win32VersionValue - .long _end - efi_head // SizeOfImage + .long _end - _head // SizeOfImage // Everything before the kernel image is considered part of the header - .long __efistub_stext_offset // SizeOfHeaders + .long efi_header_end - _head // SizeOfHeaders .long 0 // CheckSum .short 0xa // Subsystem (EFI application) .short 0 // DllCharacteristics @@ -186,10 +183,10 @@ section_table: .byte 0 .byte 0 .byte 0 // end of 0 padding of section name - .long _end - stext // VirtualSize - .long __efistub_stext_offset // VirtualAddress - .long _edata - stext // SizeOfRawData - .long __efistub_stext_offset // PointerToRawData + .long _end - efi_header_end // VirtualSize + .long efi_header_end - _head // VirtualAddress + .long _edata - efi_header_end // SizeOfRawData + .long efi_header_end - _head // PointerToRawData .long 0 // PointerToRelocations (0 for executables) .long 0 // PointerToLineNumbers (0 for executables) @@ -198,19 +195,23 @@ section_table: .long 0xe0500020 // Characteristics (section flags) /* - * EFI will load stext onwards at the 4k section alignment + * EFI will load .text onwards at the 4k section alignment * described in the PE/COFF header. To ensure that instruction * sequences using an adrp and a :lo12: immediate will function - * correctly at this alignment, we must ensure that stext is + * correctly at this alignment, we must ensure that .text is * placed at a 4k boundary in the Image to begin with. */ .align 12 +efi_header_end: #endif + __INIT + ENTRY(stext) bl preserve_boot_args bl el2_setup // Drop to EL1, w20=cpu_boot_mode adrp x24, __PHYS_OFFSET + and x23, x24, MIN_KIMG_ALIGN - 1 // KASLR offset, defaults to 0 bl set_cpu_boot_mode_flag bl __create_page_tables // x25=TTBR0, x26=TTBR1 /* @@ -219,10 +220,10 @@ ENTRY(stext) * On return, the CPU will be ready for the MMU to be turned on and * the TCR will have been set. */ - ldr x27, =__mmap_switched // address to jump to after + bl __cpu_setup // initialise processor + adr_l x27, __primary_switch // address to jump to after // MMU has been enabled - adr_l lr, __enable_mmu // return (PIC) address - b __cpu_setup // initialise processor + b __enable_mmu ENDPROC(stext) /* @@ -311,7 +312,7 @@ 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 @@ -333,7 +334,7 @@ __create_page_tables: cmp x0, x6 b.lo 1b - ldr x7, =SWAPPER_MM_MMUFLAGS + mov x7, SWAPPER_MM_MMUFLAGS /* * Create the identity mapping. @@ -389,10 +390,13 @@ __create_page_tables: * Map the kernel image (starting with PHYS_OFFSET). */ mov x0, x26 // swapper_pg_dir - mov x5, #PAGE_OFFSET + mov_q x5, KIMAGE_VADDR + TEXT_OFFSET // compile time __va(_text) + add x5, x5, x23 // add KASLR displacement create_pgd_entry x0, x5, x3, x6 - ldr x6, =KERNEL_END // __va(KERNEL_END) - mov x3, x24 // phys offset + adrp x6, _end // runtime __pa(_end) + adrp x3, _text // runtime __pa(_text) + sub x6, x6, x3 // _end - _text + add x6, x6, x5 // runtime __va(_end) create_block_map x0, x7, x3, x5, x6 /* @@ -405,8 +409,7 @@ __create_page_tables: dmb sy bl __inval_cache_range - mov lr, x27 - ret + ret x28 ENDPROC(__create_page_tables) .ltorg @@ -414,30 +417,58 @@ ENDPROC(__create_page_tables) * The following fragment of code is executed with the MMU enabled. */ .set initial_sp, init_thread_union + THREAD_START_SP -__mmap_switched: - adr_l x6, __bss_start - adr_l x7, __bss_stop - -1: cmp x6, x7 - b.hs 2f - str xzr, [x6], #8 // Clear BSS - b 1b -2: +__primary_switched: + mov x28, lr // preserve LR + adr_l x8, vectors // load VBAR_EL1 with virtual + msr vbar_el1, x8 // vector table address + isb + + // Clear BSS + adr_l x0, __bss_start + mov x1, xzr + adr_l x2, __bss_stop + sub x2, x2, x0 + bl __pi_memset + dsb ishst // Make zero page visible to PTW + adr_l sp, initial_sp, x4 + mov x4, sp + and x4, x4, #~(THREAD_SIZE - 1) + msr sp_el0, x4 // Save thread_info str_l x21, __fdt_pointer, x5 // Save FDT pointer - str_l x24, memstart_addr, x6 // Save PHYS_OFFSET + + 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 + mov x29, #0 #ifdef CONFIG_KASAN bl kasan_early_init #endif +#ifdef CONFIG_RANDOMIZE_BASE + tst x23, ~(MIN_KIMG_ALIGN - 1) // already running randomized? + b.ne 0f + mov x0, x21 // pass FDT address in x0 + mov x1, x23 // pass modulo offset in x1 + bl kaslr_early_init // parse FDT for KASLR options + cbz x0, 0f // KASLR disabled? just proceed + orr x23, x23, x0 // record KASLR offset + ret x28 // we must enable KASLR, return + // to __enable_mmu() +0: +#endif b start_kernel -ENDPROC(__mmap_switched) +ENDPROC(__primary_switched) /* * end early head section, begin head code that is also used for * 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. @@ -544,7 +575,7 @@ ENDPROC(el2_setup) * Sets the __boot_cpu_mode flag depending on the CPU boot mode passed * in x20. See arch/arm64/include/asm/virt.h for more info. */ -ENTRY(set_cpu_boot_mode_flag) +set_cpu_boot_mode_flag: adr_l x1, __boot_cpu_mode cmp w20, #BOOT_CPU_MODE_EL2 b.ne 1f @@ -577,7 +608,7 @@ ENTRY(secondary_holding_pen) bl el2_setup // Drop to EL1, w20=cpu_boot_mode bl set_cpu_boot_mode_flag mrs x0, mpidr_el1 - ldr x1, =MPIDR_HWID_BITMASK + mov_q x1, MPIDR_HWID_BITMASK and x0, x0, x1 adr_l x3, secondary_holding_pen_release pen: ldr x4, [x3] @@ -597,7 +628,7 @@ ENTRY(secondary_entry) b secondary_startup ENDPROC(secondary_entry) -ENTRY(secondary_startup) +secondary_startup: /* * Common entry point for secondary CPUs. */ @@ -605,19 +636,48 @@ ENTRY(secondary_startup) adrp x26, swapper_pg_dir bl __cpu_setup // initialise processor - ldr x21, =secondary_data - ldr x27, =__secondary_switched // address to jump to after enabling the MMU + adr_l x27, __secondary_switch // address to jump to after enabling the MMU b __enable_mmu ENDPROC(secondary_startup) -ENTRY(__secondary_switched) - ldr x0, [x21] // get secondary_data.stack +__secondary_switched: + adr_l x5, vectors + msr vbar_el1, x5 + isb + + adr_l x0, secondary_data + ldr x0, [x0, #CPU_BOOT_STACK] // get secondary_data.stack mov sp, x0 + and x0, x0, #~(THREAD_SIZE - 1) + msr sp_el0, x0 // save thread_info mov x29, #0 b secondary_start_kernel ENDPROC(__secondary_switched) /* + * The booting CPU updates the failed status @__early_cpu_boot_status, + * with MMU turned off. + * + * update_early_cpu_boot_status tmp, status + * - Corrupts tmp1, tmp2 + * - Writes 'status' to __early_cpu_boot_status and makes sure + * it is committed to memory. + */ + + .macro update_early_cpu_boot_status status, tmp1, tmp2 + mov \tmp2, #\status + str_l \tmp2, __early_cpu_boot_status, \tmp1 + dmb sy + dc ivac, \tmp1 // Invalidate potentially stale cache line + .endm + + .pushsection .data..cacheline_aligned + .align L1_CACHE_SHIFT +ENTRY(__early_cpu_boot_status) + .long 0 + .popsection + +/* * Enable the MMU. * * x0 = SCTLR_EL1 value for turning on the MMU. @@ -629,13 +689,13 @@ ENDPROC(__secondary_switched) * If it isn't, park the CPU */ .section ".idmap.text", "ax" -__enable_mmu: +ENTRY(__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 b.ne __no_granule_support - ldr x5, =vectors - msr vbar_el1, x5 + update_early_cpu_boot_status 0, x1, x2 msr ttbr0_el1, x25 // load TTBR0 msr ttbr1_el1, x26 // load TTBR1 isb @@ -649,10 +709,71 @@ __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 + + tlbi vmalle1 // Remove any stale TLB entries + dsb nsh + + msr sctlr_el1, x19 // re-enable the MMU + isb + ic iallu // flush instructions fetched + dsb nsh // via old mapping + isb +#endif br x27 ENDPROC(__enable_mmu) __no_granule_support: + /* Indicate that this CPU can't boot and is stuck in the kernel */ + update_early_cpu_boot_status CPU_STUCK_IN_KERNEL, x1, x2 +1: wfe - b __no_granule_support + wfi + b 1b ENDPROC(__no_granule_support) + +__primary_switch: +#ifdef CONFIG_RELOCATABLE + /* + * Iterate over each entry in the relocation table, and apply the + * relocations in place. + */ + ldr w9, =__rela_offset // offset to reloc table + ldr w10, =__rela_size // size of reloc table + + mov_q x11, KIMAGE_VADDR // default virtual offset + add x11, x11, x23 // actual virtual offset + add x9, x9, x11 // __va(.rela) + add x10, x9, x10 // __va(.rela) + sizeof(.rela) + +0: cmp x9, x10 + b.hs 1f + ldp x11, x12, [x9], #24 + ldr x13, [x9, #-8] + cmp w12, #R_AARCH64_RELATIVE + b.ne 0b + add x13, x13, x23 // relocate + str x13, [x11, x23] + b 0b + +1: +#endif + ldr x8, =__primary_switched + br x8 +ENDPROC(__primary_switch) + +__secondary_switch: + ldr x8, =__secondary_switched + br x8 +ENDPROC(__secondary_switch) |