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Diffstat (limited to 'arch/arm64/kernel/head.S')
| -rw-r--r-- | arch/arm64/kernel/head.S | 902 |
1 files changed, 902 insertions, 0 deletions
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S new file mode 100644 index 000000000..7b236994f --- /dev/null +++ b/arch/arm64/kernel/head.S @@ -0,0 +1,902 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Low-level CPU initialisation + * Based on arch/arm/kernel/head.S + * + * Copyright (C) 1994-2002 Russell King + * Copyright (C) 2003-2012 ARM Ltd. + * Authors: Catalin Marinas <catalin.marinas@arm.com> + * Will Deacon <will.deacon@arm.com> + */ + +#include <linux/linkage.h> +#include <linux/init.h> +#include <linux/pgtable.h> + +#include <asm/asm_pointer_auth.h> +#include <asm/assembler.h> +#include <asm/boot.h> +#include <asm/bug.h> +#include <asm/ptrace.h> +#include <asm/asm-offsets.h> +#include <asm/cache.h> +#include <asm/cputype.h> +#include <asm/el2_setup.h> +#include <asm/elf.h> +#include <asm/image.h> +#include <asm/kernel-pgtable.h> +#include <asm/kvm_arm.h> +#include <asm/memory.h> +#include <asm/pgtable-hwdef.h> +#include <asm/page.h> +#include <asm/scs.h> +#include <asm/smp.h> +#include <asm/sysreg.h> +#include <asm/thread_info.h> +#include <asm/virt.h> + +#include "efi-header.S" + +#if (PAGE_OFFSET & 0x1fffff) != 0 +#error PAGE_OFFSET must be at least 2MB aligned +#endif + +/* + * Kernel startup entry point. + * --------------------------- + * + * The requirements are: + * MMU = off, D-cache = off, I-cache = on or off, + * x0 = physical address to the FDT blob. + * + * Note that the callee-saved registers are used for storing variables + * that are useful before the MMU is enabled. The allocations are described + * in the entry routines. + */ + __HEAD + /* + * DO NOT MODIFY. Image header expected by Linux boot-loaders. + */ + efi_signature_nop // special NOP to identity as PE/COFF executable + b primary_entry // branch to kernel start, magic + .quad 0 // 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 + .ascii ARM64_IMAGE_MAGIC // Magic number + .long .Lpe_header_offset // Offset to the PE header. + + __EFI_PE_HEADER + + .section ".idmap.text","a" + + /* + * The following callee saved general purpose registers are used on the + * primary lowlevel boot path: + * + * Register Scope Purpose + * x19 primary_entry() .. start_kernel() whether we entered with the MMU on + * x20 primary_entry() .. __primary_switch() CPU boot mode + * x21 primary_entry() .. start_kernel() FDT pointer passed at boot in x0 + * x22 create_idmap() .. start_kernel() ID map VA of the DT blob + * x23 primary_entry() .. start_kernel() physical misalignment/KASLR offset + * x24 __primary_switch() linear map KASLR seed + * x25 primary_entry() .. start_kernel() supported VA size + * x28 create_idmap() callee preserved temp register + */ +SYM_CODE_START(primary_entry) + bl record_mmu_state + bl preserve_boot_args + bl create_idmap + + /* + * If we entered with the MMU and caches on, clean the ID mapped part + * of the primary boot code to the PoC so we can safely execute it with + * the MMU off. + */ + cbz x19, 0f + adrp x0, __idmap_text_start + adr_l x1, __idmap_text_end + adr_l x2, dcache_clean_poc + blr x2 +0: mov x0, x19 + bl init_kernel_el // w0=cpu_boot_mode + mov x20, x0 + + /* + * The following calls CPU setup code, see arch/arm64/mm/proc.S for + * details. + * On return, the CPU will be ready for the MMU to be turned on and + * the TCR will have been set. + */ +#if VA_BITS > 48 + mrs_s x0, SYS_ID_AA64MMFR2_EL1 + tst x0, ID_AA64MMFR2_EL1_VARange_MASK + mov x0, #VA_BITS + mov x25, #VA_BITS_MIN + csel x25, x25, x0, eq + mov x0, x25 +#endif + bl __cpu_setup // initialise processor + b __primary_switch +SYM_CODE_END(primary_entry) + + __INIT +SYM_CODE_START_LOCAL(record_mmu_state) + mrs x19, CurrentEL + cmp x19, #CurrentEL_EL2 + mrs x19, sctlr_el1 + b.ne 0f + mrs x19, sctlr_el2 +0: +CPU_LE( tbnz x19, #SCTLR_ELx_EE_SHIFT, 1f ) +CPU_BE( tbz x19, #SCTLR_ELx_EE_SHIFT, 1f ) + tst x19, #SCTLR_ELx_C // Z := (C == 0) + and x19, x19, #SCTLR_ELx_M // isolate M bit + csel x19, xzr, x19, eq // clear x19 if Z + ret + + /* + * Set the correct endianness early so all memory accesses issued + * before init_kernel_el() occur in the correct byte order. Note that + * this means the MMU must be disabled, or the active ID map will end + * up getting interpreted with the wrong byte order. + */ +1: eor x19, x19, #SCTLR_ELx_EE + bic x19, x19, #SCTLR_ELx_M + b.ne 2f + pre_disable_mmu_workaround + msr sctlr_el2, x19 + b 3f +2: pre_disable_mmu_workaround + msr sctlr_el1, x19 +3: isb + mov x19, xzr + ret +SYM_CODE_END(record_mmu_state) + +/* + * Preserve the arguments passed by the bootloader in x0 .. x3 + */ +SYM_CODE_START_LOCAL(preserve_boot_args) + mov x21, x0 // x21=FDT + + adr_l x0, boot_args // record the contents of + stp x21, x1, [x0] // x0 .. x3 at kernel entry + stp x2, x3, [x0, #16] + + cbnz x19, 0f // skip cache invalidation if MMU is on + dmb sy // needed before dc ivac with + // MMU off + + add x1, x0, #0x20 // 4 x 8 bytes + b dcache_inval_poc // tail call +0: str_l x19, mmu_enabled_at_boot, x0 + ret +SYM_CODE_END(preserve_boot_args) + +SYM_FUNC_START_LOCAL(clear_page_tables) + /* + * Clear the init page tables. + */ + adrp x0, init_pg_dir + adrp x1, init_pg_end + sub x2, x1, x0 + mov x1, xzr + b __pi_memset // tail call +SYM_FUNC_END(clear_page_tables) + +/* + * Macro to populate page table entries, these entries can be pointers to the next level + * or last level entries pointing to physical memory. + * + * tbl: page table address + * rtbl: pointer to page table or physical memory + * index: start index to write + * eindex: end index to write - [index, eindex] written to + * flags: flags for pagetable entry to or in + * inc: increment to rtbl between each entry + * tmp1: temporary variable + * + * Preserves: tbl, eindex, flags, inc + * Corrupts: index, tmp1 + * Returns: rtbl + */ + .macro populate_entries, tbl, rtbl, index, eindex, flags, inc, tmp1 +.Lpe\@: phys_to_pte \tmp1, \rtbl + orr \tmp1, \tmp1, \flags // tmp1 = table entry + str \tmp1, [\tbl, \index, lsl #3] + add \rtbl, \rtbl, \inc // rtbl = pa next level + add \index, \index, #1 + cmp \index, \eindex + b.ls .Lpe\@ + .endm + +/* + * Compute indices of table entries from virtual address range. If multiple entries + * were needed in the previous page table level then the next page table level is assumed + * to be composed of multiple pages. (This effectively scales the end index). + * + * vstart: virtual address of start of range + * vend: virtual address of end of range - we map [vstart, vend] + * shift: shift used to transform virtual address into index + * order: #imm 2log(number of entries in page table) + * istart: index in table corresponding to vstart + * iend: index in table corresponding to vend + * count: On entry: how many extra entries were required in previous level, scales + * our end index. + * On exit: returns how many extra entries required for next page table level + * + * Preserves: vstart, vend + * Returns: istart, iend, count + */ + .macro compute_indices, vstart, vend, shift, order, istart, iend, count + ubfx \istart, \vstart, \shift, \order + ubfx \iend, \vend, \shift, \order + add \iend, \iend, \count, lsl \order + sub \count, \iend, \istart + .endm + +/* + * Map memory for specified virtual address range. Each level of page table needed supports + * multiple entries. If a level requires n entries the next page table level is assumed to be + * formed from n pages. + * + * tbl: location of page table + * rtbl: address to be used for first level page table entry (typically tbl + PAGE_SIZE) + * vstart: virtual address of start of range + * vend: virtual address of end of range - we map [vstart, vend - 1] + * flags: flags to use to map last level entries + * phys: physical address corresponding to vstart - physical memory is contiguous + * order: #imm 2log(number of entries in PGD table) + * + * If extra_shift is set, an extra level will be populated if the end address does + * not fit in 'extra_shift' bits. This assumes vend is in the TTBR0 range. + * + * Temporaries: istart, iend, tmp, count, sv - these need to be different registers + * Preserves: vstart, flags + * Corrupts: tbl, rtbl, vend, istart, iend, tmp, count, sv + */ + .macro map_memory, tbl, rtbl, vstart, vend, flags, phys, order, istart, iend, tmp, count, sv, extra_shift + sub \vend, \vend, #1 + add \rtbl, \tbl, #PAGE_SIZE + mov \count, #0 + + .ifnb \extra_shift + tst \vend, #~((1 << (\extra_shift)) - 1) + b.eq .L_\@ + compute_indices \vstart, \vend, #\extra_shift, #(PAGE_SHIFT - 3), \istart, \iend, \count + mov \sv, \rtbl + populate_entries \tbl, \rtbl, \istart, \iend, #PMD_TYPE_TABLE, #PAGE_SIZE, \tmp + mov \tbl, \sv + .endif +.L_\@: + compute_indices \vstart, \vend, #PGDIR_SHIFT, #\order, \istart, \iend, \count + mov \sv, \rtbl + populate_entries \tbl, \rtbl, \istart, \iend, #PMD_TYPE_TABLE, #PAGE_SIZE, \tmp + mov \tbl, \sv + +#if SWAPPER_PGTABLE_LEVELS > 3 + compute_indices \vstart, \vend, #PUD_SHIFT, #(PAGE_SHIFT - 3), \istart, \iend, \count + mov \sv, \rtbl + populate_entries \tbl, \rtbl, \istart, \iend, #PMD_TYPE_TABLE, #PAGE_SIZE, \tmp + mov \tbl, \sv +#endif + +#if SWAPPER_PGTABLE_LEVELS > 2 + compute_indices \vstart, \vend, #SWAPPER_TABLE_SHIFT, #(PAGE_SHIFT - 3), \istart, \iend, \count + mov \sv, \rtbl + populate_entries \tbl, \rtbl, \istart, \iend, #PMD_TYPE_TABLE, #PAGE_SIZE, \tmp + mov \tbl, \sv +#endif + + compute_indices \vstart, \vend, #SWAPPER_BLOCK_SHIFT, #(PAGE_SHIFT - 3), \istart, \iend, \count + bic \rtbl, \phys, #SWAPPER_BLOCK_SIZE - 1 + populate_entries \tbl, \rtbl, \istart, \iend, \flags, #SWAPPER_BLOCK_SIZE, \tmp + .endm + +/* + * Remap a subregion created with the map_memory macro with modified attributes + * or output address. The entire remapped region must have been covered in the + * invocation of map_memory. + * + * x0: last level table address (returned in first argument to map_memory) + * x1: start VA of the existing mapping + * x2: start VA of the region to update + * x3: end VA of the region to update (exclusive) + * x4: start PA associated with the region to update + * x5: attributes to set on the updated region + * x6: order of the last level mappings + */ +SYM_FUNC_START_LOCAL(remap_region) + sub x3, x3, #1 // make end inclusive + + // Get the index offset for the start of the last level table + lsr x1, x1, x6 + bfi x1, xzr, #0, #PAGE_SHIFT - 3 + + // Derive the start and end indexes into the last level table + // associated with the provided region + lsr x2, x2, x6 + lsr x3, x3, x6 + sub x2, x2, x1 + sub x3, x3, x1 + + mov x1, #1 + lsl x6, x1, x6 // block size at this level + + populate_entries x0, x4, x2, x3, x5, x6, x7 + ret +SYM_FUNC_END(remap_region) + +SYM_FUNC_START_LOCAL(create_idmap) + mov x28, lr + /* + * The ID map carries a 1:1 mapping of the physical address range + * covered by the loaded image, which could be anywhere in DRAM. This + * means that the required size of the VA (== PA) space is decided at + * boot time, and could be more than the configured size of the VA + * space for ordinary kernel and user space mappings. + * + * There are three cases to consider here: + * - 39 <= VA_BITS < 48, and the ID map needs up to 48 VA bits to cover + * the placement of the image. In this case, we configure one extra + * level of translation on the fly for the ID map only. (This case + * also covers 42-bit VA/52-bit PA on 64k pages). + * + * - VA_BITS == 48, and the ID map needs more than 48 VA bits. This can + * only happen when using 64k pages, in which case we need to extend + * the root level table rather than add a level. Note that we can + * treat this case as 'always extended' as long as we take care not + * to program an unsupported T0SZ value into the TCR register. + * + * - Combinations that would require two additional levels of + * translation are not supported, e.g., VA_BITS==36 on 16k pages, or + * VA_BITS==39/4k pages with 5-level paging, where the input address + * requires more than 47 or 48 bits, respectively. + */ +#if (VA_BITS < 48) +#define IDMAP_PGD_ORDER (VA_BITS - PGDIR_SHIFT) +#define EXTRA_SHIFT (PGDIR_SHIFT + PAGE_SHIFT - 3) + + /* + * If VA_BITS < 48, we have to configure an additional table level. + * First, we have to verify our assumption that the current value of + * VA_BITS was chosen such that all translation levels are fully + * utilised, and that lowering T0SZ will always result in an additional + * translation level to be configured. + */ +#if VA_BITS != EXTRA_SHIFT +#error "Mismatch between VA_BITS and page size/number of translation levels" +#endif +#else +#define IDMAP_PGD_ORDER (PHYS_MASK_SHIFT - PGDIR_SHIFT) +#define EXTRA_SHIFT + /* + * If VA_BITS == 48, we don't have to configure an additional + * translation level, but the top-level table has more entries. + */ +#endif + adrp x0, init_idmap_pg_dir + adrp x3, _text + adrp x6, _end + MAX_FDT_SIZE + SWAPPER_BLOCK_SIZE + mov_q x7, SWAPPER_RX_MMUFLAGS + + map_memory x0, x1, x3, x6, x7, x3, IDMAP_PGD_ORDER, x10, x11, x12, x13, x14, EXTRA_SHIFT + + /* Remap the kernel page tables r/w in the ID map */ + adrp x1, _text + adrp x2, init_pg_dir + adrp x3, init_pg_end + bic x4, x2, #SWAPPER_BLOCK_SIZE - 1 + mov_q x5, SWAPPER_RW_MMUFLAGS + mov x6, #SWAPPER_BLOCK_SHIFT + bl remap_region + + /* Remap the FDT after the kernel image */ + adrp x1, _text + adrp x22, _end + SWAPPER_BLOCK_SIZE + bic x2, x22, #SWAPPER_BLOCK_SIZE - 1 + bfi x22, x21, #0, #SWAPPER_BLOCK_SHIFT // remapped FDT address + add x3, x2, #MAX_FDT_SIZE + SWAPPER_BLOCK_SIZE + bic x4, x21, #SWAPPER_BLOCK_SIZE - 1 + mov_q x5, SWAPPER_RW_MMUFLAGS + mov x6, #SWAPPER_BLOCK_SHIFT + bl remap_region + + /* + * Since the page tables have been populated with non-cacheable + * accesses (MMU disabled), invalidate those tables again to + * remove any speculatively loaded cache lines. + */ + cbnz x19, 0f // skip cache invalidation if MMU is on + dmb sy + + adrp x0, init_idmap_pg_dir + adrp x1, init_idmap_pg_end + bl dcache_inval_poc +0: ret x28 +SYM_FUNC_END(create_idmap) + +SYM_FUNC_START_LOCAL(create_kernel_mapping) + adrp x0, init_pg_dir + mov_q x5, KIMAGE_VADDR // compile time __va(_text) +#ifdef CONFIG_RELOCATABLE + add x5, x5, x23 // add KASLR displacement +#endif + 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) + mov_q x7, SWAPPER_RW_MMUFLAGS + + map_memory x0, x1, x5, x6, x7, x3, (VA_BITS - PGDIR_SHIFT), x10, x11, x12, x13, x14 + + dsb ishst // sync with page table walker + ret +SYM_FUNC_END(create_kernel_mapping) + + /* + * Initialize CPU registers with task-specific and cpu-specific context. + * + * Create a final frame record at task_pt_regs(current)->stackframe, so + * that the unwinder can identify the final frame record of any task by + * its location in the task stack. We reserve the entire pt_regs space + * for consistency with user tasks and kthreads. + */ + .macro init_cpu_task tsk, tmp1, tmp2 + msr sp_el0, \tsk + + ldr \tmp1, [\tsk, #TSK_STACK] + add sp, \tmp1, #THREAD_SIZE + sub sp, sp, #PT_REGS_SIZE + + stp xzr, xzr, [sp, #S_STACKFRAME] + add x29, sp, #S_STACKFRAME + + scs_load_current + + adr_l \tmp1, __per_cpu_offset + ldr w\tmp2, [\tsk, #TSK_TI_CPU] + ldr \tmp1, [\tmp1, \tmp2, lsl #3] + set_this_cpu_offset \tmp1 + .endm + +/* + * The following fragment of code is executed with the MMU enabled. + * + * x0 = __pa(KERNEL_START) + */ +SYM_FUNC_START_LOCAL(__primary_switched) + adr_l x4, init_task + init_cpu_task x4, x5, x6 + + adr_l x8, vectors // load VBAR_EL1 with virtual + msr vbar_el1, x8 // vector table address + isb + + stp x29, x30, [sp, #-16]! + mov x29, sp + + str_l x21, __fdt_pointer, x5 // Save FDT pointer + + ldr_l x4, kimage_vaddr // Save the offset between + sub x4, x4, x0 // the kernel virtual and + str_l x4, kimage_voffset, x5 // physical mappings + + mov x0, x20 + bl set_cpu_boot_mode_flag + + // 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 + +#if VA_BITS > 48 + adr_l x8, vabits_actual // Set this early so KASAN early init + str x25, [x8] // ... observes the correct value + dc civac, x8 // Make visible to booting secondaries +#endif + +#ifdef CONFIG_RANDOMIZE_BASE + adrp x5, memstart_offset_seed // Save KASLR linear map seed + strh w24, [x5, :lo12:memstart_offset_seed] +#endif +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) + bl kasan_early_init +#endif + mov x0, x21 // pass FDT address in x0 + bl early_fdt_map // Try mapping the FDT early + mov x0, x20 // pass the full boot status + bl init_feature_override // Parse cpu feature overrides +#ifdef CONFIG_UNWIND_PATCH_PAC_INTO_SCS + bl scs_patch_vmlinux +#endif + mov x0, x20 + bl finalise_el2 // Prefer VHE if possible + ldp x29, x30, [sp], #16 + bl start_kernel + ASM_BUG() +SYM_FUNC_END(__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 ".idmap.text","a" + +/* + * Starting from EL2 or EL1, configure the CPU to execute at the highest + * reachable EL supported by the kernel in a chosen default state. If dropping + * from EL2 to EL1, configure EL2 before configuring EL1. + * + * Since we cannot always rely on ERET synchronizing writes to sysregs (e.g. if + * SCTLR_ELx.EOS is clear), we place an ISB prior to ERET. + * + * Returns either BOOT_CPU_MODE_EL1 or BOOT_CPU_MODE_EL2 in x0 if + * booted in EL1 or EL2 respectively, with the top 32 bits containing + * potential context flags. These flags are *not* stored in __boot_cpu_mode. + * + * x0: whether we are being called from the primary boot path with the MMU on + */ +SYM_FUNC_START(init_kernel_el) + mrs x1, CurrentEL + cmp x1, #CurrentEL_EL2 + b.eq init_el2 + +SYM_INNER_LABEL(init_el1, SYM_L_LOCAL) + mov_q x0, INIT_SCTLR_EL1_MMU_OFF + pre_disable_mmu_workaround + msr sctlr_el1, x0 + isb + mov_q x0, INIT_PSTATE_EL1 + msr spsr_el1, x0 + msr elr_el1, lr + mov w0, #BOOT_CPU_MODE_EL1 + eret + +SYM_INNER_LABEL(init_el2, SYM_L_LOCAL) + msr elr_el2, lr + + // clean all HYP code to the PoC if we booted at EL2 with the MMU on + cbz x0, 0f + adrp x0, __hyp_idmap_text_start + adr_l x1, __hyp_text_end + adr_l x2, dcache_clean_poc + blr x2 +0: + mov_q x0, HCR_HOST_NVHE_FLAGS + msr hcr_el2, x0 + isb + + init_el2_state + + /* Hypervisor stub */ + adr_l x0, __hyp_stub_vectors + msr vbar_el2, x0 + isb + + mov_q x1, INIT_SCTLR_EL1_MMU_OFF + + /* + * Fruity CPUs seem to have HCR_EL2.E2H set to RES1, + * making it impossible to start in nVHE mode. Is that + * compliant with the architecture? Absolutely not! + */ + mrs x0, hcr_el2 + and x0, x0, #HCR_E2H + cbz x0, 1f + + /* Set a sane SCTLR_EL1, the VHE way */ + pre_disable_mmu_workaround + msr_s SYS_SCTLR_EL12, x1 + mov x2, #BOOT_CPU_FLAG_E2H + b 2f + +1: + pre_disable_mmu_workaround + msr sctlr_el1, x1 + mov x2, xzr +2: + __init_el2_nvhe_prepare_eret + + mov w0, #BOOT_CPU_MODE_EL2 + orr x0, x0, x2 + eret +SYM_FUNC_END(init_kernel_el) + + /* + * This provides a "holding pen" for platforms to hold all secondary + * cores are held until we're ready for them to initialise. + */ +SYM_FUNC_START(secondary_holding_pen) + mov x0, xzr + bl init_kernel_el // w0=cpu_boot_mode + mrs x2, mpidr_el1 + mov_q x1, MPIDR_HWID_BITMASK + and x2, x2, x1 + adr_l x3, secondary_holding_pen_release +pen: ldr x4, [x3] + cmp x4, x2 + b.eq secondary_startup + wfe + b pen +SYM_FUNC_END(secondary_holding_pen) + + /* + * Secondary entry point that jumps straight into the kernel. Only to + * be used where CPUs are brought online dynamically by the kernel. + */ +SYM_FUNC_START(secondary_entry) + mov x0, xzr + bl init_kernel_el // w0=cpu_boot_mode + b secondary_startup +SYM_FUNC_END(secondary_entry) + +SYM_FUNC_START_LOCAL(secondary_startup) + /* + * Common entry point for secondary CPUs. + */ + mov x20, x0 // preserve boot mode + bl __cpu_secondary_check52bitva +#if VA_BITS > 48 + ldr_l x0, vabits_actual +#endif + bl __cpu_setup // initialise processor + adrp x1, swapper_pg_dir + adrp x2, idmap_pg_dir + bl __enable_mmu + ldr x8, =__secondary_switched + br x8 +SYM_FUNC_END(secondary_startup) + + .text +SYM_FUNC_START_LOCAL(__secondary_switched) + mov x0, x20 + bl set_cpu_boot_mode_flag + + mov x0, x20 + bl finalise_el2 + + str_l xzr, __early_cpu_boot_status, x3 + adr_l x5, vectors + msr vbar_el1, x5 + isb + + adr_l x0, secondary_data + ldr x2, [x0, #CPU_BOOT_TASK] + cbz x2, __secondary_too_slow + + init_cpu_task x2, x1, x3 + +#ifdef CONFIG_ARM64_PTR_AUTH + ptrauth_keys_init_cpu x2, x3, x4, x5 +#endif + + bl secondary_start_kernel + ASM_BUG() +SYM_FUNC_END(__secondary_switched) + +SYM_FUNC_START_LOCAL(__secondary_too_slow) + wfe + wfi + b __secondary_too_slow +SYM_FUNC_END(__secondary_too_slow) + +/* + * Sets the __boot_cpu_mode flag depending on the CPU boot mode passed + * in w0. See arch/arm64/include/asm/virt.h for more info. + */ +SYM_FUNC_START_LOCAL(set_cpu_boot_mode_flag) + adr_l x1, __boot_cpu_mode + cmp w0, #BOOT_CPU_MODE_EL2 + b.ne 1f + add x1, x1, #4 +1: str w0, [x1] // Save CPU boot mode + ret +SYM_FUNC_END(set_cpu_boot_mode_flag) + +/* + * 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 + adr_l \tmp1, __early_cpu_boot_status + str \tmp2, [\tmp1] + dmb sy + dc ivac, \tmp1 // Invalidate potentially stale cache line + .endm + +/* + * Enable the MMU. + * + * x0 = SCTLR_EL1 value for turning on the MMU. + * x1 = TTBR1_EL1 value + * x2 = ID map root table address + * + * Returns to the caller via x30/lr. This requires the caller to be covered + * by the .idmap.text section. + * + * Checks if the selected granule size is supported by the CPU. + * If it isn't, park the CPU + */ + .section ".idmap.text","a" +SYM_FUNC_START(__enable_mmu) + mrs x3, ID_AA64MMFR0_EL1 + ubfx x3, x3, #ID_AA64MMFR0_EL1_TGRAN_SHIFT, 4 + cmp x3, #ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MIN + b.lt __no_granule_support + cmp x3, #ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MAX + b.gt __no_granule_support + phys_to_ttbr x2, x2 + msr ttbr0_el1, x2 // load TTBR0 + load_ttbr1 x1, x1, x3 + + set_sctlr_el1 x0 + + ret +SYM_FUNC_END(__enable_mmu) + +SYM_FUNC_START(__cpu_secondary_check52bitva) +#if VA_BITS > 48 + ldr_l x0, vabits_actual + cmp x0, #52 + b.ne 2f + + mrs_s x0, SYS_ID_AA64MMFR2_EL1 + and x0, x0, ID_AA64MMFR2_EL1_VARange_MASK + cbnz x0, 2f + + update_early_cpu_boot_status \ + CPU_STUCK_IN_KERNEL | CPU_STUCK_REASON_52_BIT_VA, x0, x1 +1: wfe + wfi + b 1b + +#endif +2: ret +SYM_FUNC_END(__cpu_secondary_check52bitva) + +SYM_FUNC_START_LOCAL(__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 | CPU_STUCK_REASON_NO_GRAN, x1, x2 +1: + wfe + wfi + b 1b +SYM_FUNC_END(__no_granule_support) + +#ifdef CONFIG_RELOCATABLE +SYM_FUNC_START_LOCAL(__relocate_kernel) + /* + * Iterate over each entry in the relocation table, and apply the + * relocations in place. + */ + adr_l x9, __rela_start + adr_l x10, __rela_end + mov_q x11, KIMAGE_VADDR // default virtual offset + add x11, x11, x23 // actual virtual offset + +0: cmp x9, x10 + b.hs 1f + ldp x12, x13, [x9], #24 + ldr x14, [x9, #-8] + cmp w13, #R_AARCH64_RELATIVE + b.ne 0b + add x14, x14, x23 // relocate + str x14, [x12, x23] + b 0b + +1: +#ifdef CONFIG_RELR + /* + * Apply RELR relocations. + * + * RELR is a compressed format for storing relative relocations. The + * encoded sequence of entries looks like: + * [ AAAAAAAA BBBBBBB1 BBBBBBB1 ... AAAAAAAA BBBBBB1 ... ] + * + * i.e. start with an address, followed by any number of bitmaps. The + * address entry encodes 1 relocation. The subsequent bitmap entries + * encode up to 63 relocations each, at subsequent offsets following + * the last address entry. + * + * The bitmap entries must have 1 in the least significant bit. The + * assumption here is that an address cannot have 1 in lsb. Odd + * addresses are not supported. Any odd addresses are stored in the RELA + * section, which is handled above. + * + * Excluding the least significant bit in the bitmap, each non-zero + * bit in the bitmap represents a relocation to be applied to + * a corresponding machine word that follows the base address + * word. The second least significant bit represents the machine + * word immediately following the initial address, and each bit + * that follows represents the next word, in linear order. As such, + * a single bitmap can encode up to 63 relocations in a 64-bit object. + * + * In this implementation we store the address of the next RELR table + * entry in x9, the address being relocated by the current address or + * bitmap entry in x13 and the address being relocated by the current + * bit in x14. + */ + adr_l x9, __relr_start + adr_l x10, __relr_end + +2: cmp x9, x10 + b.hs 7f + ldr x11, [x9], #8 + tbnz x11, #0, 3f // branch to handle bitmaps + add x13, x11, x23 + ldr x12, [x13] // relocate address entry + add x12, x12, x23 + str x12, [x13], #8 // adjust to start of bitmap + b 2b + +3: mov x14, x13 +4: lsr x11, x11, #1 + cbz x11, 6f + tbz x11, #0, 5f // skip bit if not set + ldr x12, [x14] // relocate bit + add x12, x12, x23 + str x12, [x14] + +5: add x14, x14, #8 // move to next bit's address + b 4b + +6: /* + * Move to the next bitmap's address. 8 is the word size, and 63 is the + * number of significant bits in a bitmap entry. + */ + add x13, x13, #(8 * 63) + b 2b + +7: +#endif + ret + +SYM_FUNC_END(__relocate_kernel) +#endif + +SYM_FUNC_START_LOCAL(__primary_switch) + adrp x1, reserved_pg_dir + adrp x2, init_idmap_pg_dir + bl __enable_mmu +#ifdef CONFIG_RELOCATABLE + adrp x23, KERNEL_START + and x23, x23, MIN_KIMG_ALIGN - 1 +#ifdef CONFIG_RANDOMIZE_BASE + mov x0, x22 + adrp x1, init_pg_end + mov sp, x1 + mov x29, xzr + bl __pi_kaslr_early_init + and x24, x0, #SZ_2M - 1 // capture memstart offset seed + bic x0, x0, #SZ_2M - 1 + orr x23, x23, x0 // record kernel offset +#endif +#endif + bl clear_page_tables + bl create_kernel_mapping + + adrp x1, init_pg_dir + load_ttbr1 x1, x1, x2 +#ifdef CONFIG_RELOCATABLE + bl __relocate_kernel +#endif + ldr x8, =__primary_switched + adrp x0, KERNEL_START // __pa(KERNEL_START) + br x8 +SYM_FUNC_END(__primary_switch) |