1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * Low-level CPU initialisation 4 * Based on arch/arm/kernel/head.S 5 * 6 * Copyright (C) 1994-2002 Russell King 7 * Copyright (C) 2003-2012 ARM Ltd. 8 * Authors: Catalin Marinas <catalin.marinas@arm.com> 9 * Will Deacon <will.deacon@arm.com> 10 */ 11 12#include <linux/linkage.h> 13#include <linux/init.h> 14#include <linux/pgtable.h> 15 16#include <asm/asm_pointer_auth.h> 17#include <asm/assembler.h> 18#include <asm/boot.h> 19#include <asm/bug.h> 20#include <asm/ptrace.h> 21#include <asm/asm-offsets.h> 22#include <asm/cache.h> 23#include <asm/cputype.h> 24#include <asm/el2_setup.h> 25#include <asm/elf.h> 26#include <asm/image.h> 27#include <asm/kernel-pgtable.h> 28#include <asm/kvm_arm.h> 29#include <asm/memory.h> 30#include <asm/pgtable-hwdef.h> 31#include <asm/page.h> 32#include <asm/scs.h> 33#include <asm/smp.h> 34#include <asm/sysreg.h> 35#include <asm/thread_info.h> 36#include <asm/virt.h> 37 38#include "efi-header.S" 39 40#if (PAGE_OFFSET & 0x1fffff) != 0 41#error PAGE_OFFSET must be at least 2MB aligned 42#endif 43 44/* 45 * Kernel startup entry point. 46 * --------------------------- 47 * 48 * The requirements are: 49 * MMU = off, D-cache = off, I-cache = on or off, 50 * x0 = physical address to the FDT blob. 51 * 52 * Note that the callee-saved registers are used for storing variables 53 * that are useful before the MMU is enabled. The allocations are described 54 * in the entry routines. 55 */ 56 __HEAD 57 /* 58 * DO NOT MODIFY. Image header expected by Linux boot-loaders. 59 */ 60 efi_signature_nop // special NOP to identity as PE/COFF executable 61 b primary_entry // branch to kernel start, magic 62 .quad 0 // Image load offset from start of RAM, little-endian 63 le64sym _kernel_size_le // Effective size of kernel image, little-endian 64 le64sym _kernel_flags_le // Informative flags, little-endian 65 .quad 0 // reserved 66 .quad 0 // reserved 67 .quad 0 // reserved 68 .ascii ARM64_IMAGE_MAGIC // Magic number 69 .long .Lpe_header_offset // Offset to the PE header. 70 71 __EFI_PE_HEADER 72 73 .section ".idmap.text","a" 74 75 /* 76 * The following callee saved general purpose registers are used on the 77 * primary lowlevel boot path: 78 * 79 * Register Scope Purpose 80 * x19 primary_entry() .. start_kernel() whether we entered with the MMU on 81 * x20 primary_entry() .. __primary_switch() CPU boot mode 82 * x21 primary_entry() .. start_kernel() FDT pointer passed at boot in x0 83 * x22 create_idmap() .. start_kernel() ID map VA of the DT blob 84 * x23 primary_entry() .. start_kernel() physical misalignment/KASLR offset 85 * x24 __primary_switch() linear map KASLR seed 86 * x25 primary_entry() .. start_kernel() supported VA size 87 * x28 create_idmap() callee preserved temp register 88 */ 89SYM_CODE_START(primary_entry) 90 bl record_mmu_state 91 bl preserve_boot_args 92 bl create_idmap 93 94 /* 95 * If we entered with the MMU and caches on, clean the ID mapped part 96 * of the primary boot code to the PoC so we can safely execute it with 97 * the MMU off. 98 */ 99 cbz x19, 0f 100 adrp x0, __idmap_text_start 101 adr_l x1, __idmap_text_end 102 adr_l x2, dcache_clean_poc 103 blr x2 1040: mov x0, x19 105 bl init_kernel_el // w0=cpu_boot_mode 106 mov x20, x0 107 108 /* 109 * The following calls CPU setup code, see arch/arm64/mm/proc.S for 110 * details. 111 * On return, the CPU will be ready for the MMU to be turned on and 112 * the TCR will have been set. 113 */ 114#if VA_BITS > 48 115 mrs_s x0, SYS_ID_AA64MMFR2_EL1 116 tst x0, #0xf << ID_AA64MMFR2_EL1_VARange_SHIFT 117 mov x0, #VA_BITS 118 mov x25, #VA_BITS_MIN 119 csel x25, x25, x0, eq 120 mov x0, x25 121#endif 122 bl __cpu_setup // initialise processor 123 b __primary_switch 124SYM_CODE_END(primary_entry) 125 126 __INIT 127SYM_CODE_START_LOCAL(record_mmu_state) 128 mrs x19, CurrentEL 129 cmp x19, #CurrentEL_EL2 130 mrs x19, sctlr_el1 131 b.ne 0f 132 mrs x19, sctlr_el2 1330: 134CPU_LE( tbnz x19, #SCTLR_ELx_EE_SHIFT, 1f ) 135CPU_BE( tbz x19, #SCTLR_ELx_EE_SHIFT, 1f ) 136 tst x19, #SCTLR_ELx_C // Z := (C == 0) 137 and x19, x19, #SCTLR_ELx_M // isolate M bit 138 csel x19, xzr, x19, eq // clear x19 if Z 139 ret 140 141 /* 142 * Set the correct endianness early so all memory accesses issued 143 * before init_kernel_el() occur in the correct byte order. Note that 144 * this means the MMU must be disabled, or the active ID map will end 145 * up getting interpreted with the wrong byte order. 146 */ 1471: eor x19, x19, #SCTLR_ELx_EE 148 bic x19, x19, #SCTLR_ELx_M 149 b.ne 2f 150 pre_disable_mmu_workaround 151 msr sctlr_el2, x19 152 b 3f 1532: pre_disable_mmu_workaround 154 msr sctlr_el1, x19 1553: isb 156 mov x19, xzr 157 ret 158SYM_CODE_END(record_mmu_state) 159 160/* 161 * Preserve the arguments passed by the bootloader in x0 .. x3 162 */ 163SYM_CODE_START_LOCAL(preserve_boot_args) 164 mov x21, x0 // x21=FDT 165 166 adr_l x0, boot_args // record the contents of 167 stp x21, x1, [x0] // x0 .. x3 at kernel entry 168 stp x2, x3, [x0, #16] 169 170 cbnz x19, 0f // skip cache invalidation if MMU is on 171 dmb sy // needed before dc ivac with 172 // MMU off 173 174 add x1, x0, #0x20 // 4 x 8 bytes 175 b dcache_inval_poc // tail call 1760: str_l x19, mmu_enabled_at_boot, x0 177 ret 178SYM_CODE_END(preserve_boot_args) 179 180SYM_FUNC_START_LOCAL(clear_page_tables) 181 /* 182 * Clear the init page tables. 183 */ 184 adrp x0, init_pg_dir 185 adrp x1, init_pg_end 186 sub x2, x1, x0 187 mov x1, xzr 188 b __pi_memset // tail call 189SYM_FUNC_END(clear_page_tables) 190 191/* 192 * Macro to populate page table entries, these entries can be pointers to the next level 193 * or last level entries pointing to physical memory. 194 * 195 * tbl: page table address 196 * rtbl: pointer to page table or physical memory 197 * index: start index to write 198 * eindex: end index to write - [index, eindex] written to 199 * flags: flags for pagetable entry to or in 200 * inc: increment to rtbl between each entry 201 * tmp1: temporary variable 202 * 203 * Preserves: tbl, eindex, flags, inc 204 * Corrupts: index, tmp1 205 * Returns: rtbl 206 */ 207 .macro populate_entries, tbl, rtbl, index, eindex, flags, inc, tmp1 208.Lpe\@: phys_to_pte \tmp1, \rtbl 209 orr \tmp1, \tmp1, \flags // tmp1 = table entry 210 str \tmp1, [\tbl, \index, lsl #3] 211 add \rtbl, \rtbl, \inc // rtbl = pa next level 212 add \index, \index, #1 213 cmp \index, \eindex 214 b.ls .Lpe\@ 215 .endm 216 217/* 218 * Compute indices of table entries from virtual address range. If multiple entries 219 * were needed in the previous page table level then the next page table level is assumed 220 * to be composed of multiple pages. (This effectively scales the end index). 221 * 222 * vstart: virtual address of start of range 223 * vend: virtual address of end of range - we map [vstart, vend] 224 * shift: shift used to transform virtual address into index 225 * order: #imm 2log(number of entries in page table) 226 * istart: index in table corresponding to vstart 227 * iend: index in table corresponding to vend 228 * count: On entry: how many extra entries were required in previous level, scales 229 * our end index. 230 * On exit: returns how many extra entries required for next page table level 231 * 232 * Preserves: vstart, vend 233 * Returns: istart, iend, count 234 */ 235 .macro compute_indices, vstart, vend, shift, order, istart, iend, count 236 ubfx \istart, \vstart, \shift, \order 237 ubfx \iend, \vend, \shift, \order 238 add \iend, \iend, \count, lsl \order 239 sub \count, \iend, \istart 240 .endm 241 242/* 243 * Map memory for specified virtual address range. Each level of page table needed supports 244 * multiple entries. If a level requires n entries the next page table level is assumed to be 245 * formed from n pages. 246 * 247 * tbl: location of page table 248 * rtbl: address to be used for first level page table entry (typically tbl + PAGE_SIZE) 249 * vstart: virtual address of start of range 250 * vend: virtual address of end of range - we map [vstart, vend - 1] 251 * flags: flags to use to map last level entries 252 * phys: physical address corresponding to vstart - physical memory is contiguous 253 * order: #imm 2log(number of entries in PGD table) 254 * 255 * If extra_shift is set, an extra level will be populated if the end address does 256 * not fit in 'extra_shift' bits. This assumes vend is in the TTBR0 range. 257 * 258 * Temporaries: istart, iend, tmp, count, sv - these need to be different registers 259 * Preserves: vstart, flags 260 * Corrupts: tbl, rtbl, vend, istart, iend, tmp, count, sv 261 */ 262 .macro map_memory, tbl, rtbl, vstart, vend, flags, phys, order, istart, iend, tmp, count, sv, extra_shift 263 sub \vend, \vend, #1 264 add \rtbl, \tbl, #PAGE_SIZE 265 mov \count, #0 266 267 .ifnb \extra_shift 268 tst \vend, #~((1 << (\extra_shift)) - 1) 269 b.eq .L_\@ 270 compute_indices \vstart, \vend, #\extra_shift, #(PAGE_SHIFT - 3), \istart, \iend, \count 271 mov \sv, \rtbl 272 populate_entries \tbl, \rtbl, \istart, \iend, #PMD_TYPE_TABLE, #PAGE_SIZE, \tmp 273 mov \tbl, \sv 274 .endif 275.L_\@: 276 compute_indices \vstart, \vend, #PGDIR_SHIFT, #\order, \istart, \iend, \count 277 mov \sv, \rtbl 278 populate_entries \tbl, \rtbl, \istart, \iend, #PMD_TYPE_TABLE, #PAGE_SIZE, \tmp 279 mov \tbl, \sv 280 281#if SWAPPER_PGTABLE_LEVELS > 3 282 compute_indices \vstart, \vend, #PUD_SHIFT, #(PAGE_SHIFT - 3), \istart, \iend, \count 283 mov \sv, \rtbl 284 populate_entries \tbl, \rtbl, \istart, \iend, #PMD_TYPE_TABLE, #PAGE_SIZE, \tmp 285 mov \tbl, \sv 286#endif 287 288#if SWAPPER_PGTABLE_LEVELS > 2 289 compute_indices \vstart, \vend, #SWAPPER_TABLE_SHIFT, #(PAGE_SHIFT - 3), \istart, \iend, \count 290 mov \sv, \rtbl 291 populate_entries \tbl, \rtbl, \istart, \iend, #PMD_TYPE_TABLE, #PAGE_SIZE, \tmp 292 mov \tbl, \sv 293#endif 294 295 compute_indices \vstart, \vend, #SWAPPER_BLOCK_SHIFT, #(PAGE_SHIFT - 3), \istart, \iend, \count 296 bic \rtbl, \phys, #SWAPPER_BLOCK_SIZE - 1 297 populate_entries \tbl, \rtbl, \istart, \iend, \flags, #SWAPPER_BLOCK_SIZE, \tmp 298 .endm 299 300/* 301 * Remap a subregion created with the map_memory macro with modified attributes 302 * or output address. The entire remapped region must have been covered in the 303 * invocation of map_memory. 304 * 305 * x0: last level table address (returned in first argument to map_memory) 306 * x1: start VA of the existing mapping 307 * x2: start VA of the region to update 308 * x3: end VA of the region to update (exclusive) 309 * x4: start PA associated with the region to update 310 * x5: attributes to set on the updated region 311 * x6: order of the last level mappings 312 */ 313SYM_FUNC_START_LOCAL(remap_region) 314 sub x3, x3, #1 // make end inclusive 315 316 // Get the index offset for the start of the last level table 317 lsr x1, x1, x6 318 bfi x1, xzr, #0, #PAGE_SHIFT - 3 319 320 // Derive the start and end indexes into the last level table 321 // associated with the provided region 322 lsr x2, x2, x6 323 lsr x3, x3, x6 324 sub x2, x2, x1 325 sub x3, x3, x1 326 327 mov x1, #1 328 lsl x6, x1, x6 // block size at this level 329 330 populate_entries x0, x4, x2, x3, x5, x6, x7 331 ret 332SYM_FUNC_END(remap_region) 333 334SYM_FUNC_START_LOCAL(create_idmap) 335 mov x28, lr 336 /* 337 * The ID map carries a 1:1 mapping of the physical address range 338 * covered by the loaded image, which could be anywhere in DRAM. This 339 * means that the required size of the VA (== PA) space is decided at 340 * boot time, and could be more than the configured size of the VA 341 * space for ordinary kernel and user space mappings. 342 * 343 * There are three cases to consider here: 344 * - 39 <= VA_BITS < 48, and the ID map needs up to 48 VA bits to cover 345 * the placement of the image. In this case, we configure one extra 346 * level of translation on the fly for the ID map only. (This case 347 * also covers 42-bit VA/52-bit PA on 64k pages). 348 * 349 * - VA_BITS == 48, and the ID map needs more than 48 VA bits. This can 350 * only happen when using 64k pages, in which case we need to extend 351 * the root level table rather than add a level. Note that we can 352 * treat this case as 'always extended' as long as we take care not 353 * to program an unsupported T0SZ value into the TCR register. 354 * 355 * - Combinations that would require two additional levels of 356 * translation are not supported, e.g., VA_BITS==36 on 16k pages, or 357 * VA_BITS==39/4k pages with 5-level paging, where the input address 358 * requires more than 47 or 48 bits, respectively. 359 */ 360#if (VA_BITS < 48) 361#define IDMAP_PGD_ORDER (VA_BITS - PGDIR_SHIFT) 362#define EXTRA_SHIFT (PGDIR_SHIFT + PAGE_SHIFT - 3) 363 364 /* 365 * If VA_BITS < 48, we have to configure an additional table level. 366 * First, we have to verify our assumption that the current value of 367 * VA_BITS was chosen such that all translation levels are fully 368 * utilised, and that lowering T0SZ will always result in an additional 369 * translation level to be configured. 370 */ 371#if VA_BITS != EXTRA_SHIFT 372#error "Mismatch between VA_BITS and page size/number of translation levels" 373#endif 374#else 375#define IDMAP_PGD_ORDER (PHYS_MASK_SHIFT - PGDIR_SHIFT) 376#define EXTRA_SHIFT 377 /* 378 * If VA_BITS == 48, we don't have to configure an additional 379 * translation level, but the top-level table has more entries. 380 */ 381#endif 382 adrp x0, init_idmap_pg_dir 383 adrp x3, _text 384 adrp x6, _end + MAX_FDT_SIZE + SWAPPER_BLOCK_SIZE 385 mov x7, SWAPPER_RX_MMUFLAGS 386 387 map_memory x0, x1, x3, x6, x7, x3, IDMAP_PGD_ORDER, x10, x11, x12, x13, x14, EXTRA_SHIFT 388 389 /* Remap the kernel page tables r/w in the ID map */ 390 adrp x1, _text 391 adrp x2, init_pg_dir 392 adrp x3, init_pg_end 393 bic x4, x2, #SWAPPER_BLOCK_SIZE - 1 394 mov x5, SWAPPER_RW_MMUFLAGS 395 mov x6, #SWAPPER_BLOCK_SHIFT 396 bl remap_region 397 398 /* Remap the FDT after the kernel image */ 399 adrp x1, _text 400 adrp x22, _end + SWAPPER_BLOCK_SIZE 401 bic x2, x22, #SWAPPER_BLOCK_SIZE - 1 402 bfi x22, x21, #0, #SWAPPER_BLOCK_SHIFT // remapped FDT address 403 add x3, x2, #MAX_FDT_SIZE + SWAPPER_BLOCK_SIZE 404 bic x4, x21, #SWAPPER_BLOCK_SIZE - 1 405 mov x5, SWAPPER_RW_MMUFLAGS 406 mov x6, #SWAPPER_BLOCK_SHIFT 407 bl remap_region 408 409 /* 410 * Since the page tables have been populated with non-cacheable 411 * accesses (MMU disabled), invalidate those tables again to 412 * remove any speculatively loaded cache lines. 413 */ 414 cbnz x19, 0f // skip cache invalidation if MMU is on 415 dmb sy 416 417 adrp x0, init_idmap_pg_dir 418 adrp x1, init_idmap_pg_end 419 bl dcache_inval_poc 4200: ret x28 421SYM_FUNC_END(create_idmap) 422 423SYM_FUNC_START_LOCAL(create_kernel_mapping) 424 adrp x0, init_pg_dir 425 mov_q x5, KIMAGE_VADDR // compile time __va(_text) 426#ifdef CONFIG_RELOCATABLE 427 add x5, x5, x23 // add KASLR displacement 428#endif 429 adrp x6, _end // runtime __pa(_end) 430 adrp x3, _text // runtime __pa(_text) 431 sub x6, x6, x3 // _end - _text 432 add x6, x6, x5 // runtime __va(_end) 433 mov x7, SWAPPER_RW_MMUFLAGS 434 435 map_memory x0, x1, x5, x6, x7, x3, (VA_BITS - PGDIR_SHIFT), x10, x11, x12, x13, x14 436 437 dsb ishst // sync with page table walker 438 ret 439SYM_FUNC_END(create_kernel_mapping) 440 441 /* 442 * Initialize CPU registers with task-specific and cpu-specific context. 443 * 444 * Create a final frame record at task_pt_regs(current)->stackframe, so 445 * that the unwinder can identify the final frame record of any task by 446 * its location in the task stack. We reserve the entire pt_regs space 447 * for consistency with user tasks and kthreads. 448 */ 449 .macro init_cpu_task tsk, tmp1, tmp2 450 msr sp_el0, \tsk 451 452 ldr \tmp1, [\tsk, #TSK_STACK] 453 add sp, \tmp1, #THREAD_SIZE 454 sub sp, sp, #PT_REGS_SIZE 455 456 stp xzr, xzr, [sp, #S_STACKFRAME] 457 add x29, sp, #S_STACKFRAME 458 459 scs_load_current 460 461 adr_l \tmp1, __per_cpu_offset 462 ldr w\tmp2, [\tsk, #TSK_TI_CPU] 463 ldr \tmp1, [\tmp1, \tmp2, lsl #3] 464 set_this_cpu_offset \tmp1 465 .endm 466 467/* 468 * The following fragment of code is executed with the MMU enabled. 469 * 470 * x0 = __pa(KERNEL_START) 471 */ 472SYM_FUNC_START_LOCAL(__primary_switched) 473 adr_l x4, init_task 474 init_cpu_task x4, x5, x6 475 476 adr_l x8, vectors // load VBAR_EL1 with virtual 477 msr vbar_el1, x8 // vector table address 478 isb 479 480 stp x29, x30, [sp, #-16]! 481 mov x29, sp 482 483 str_l x21, __fdt_pointer, x5 // Save FDT pointer 484 485 ldr_l x4, kimage_vaddr // Save the offset between 486 sub x4, x4, x0 // the kernel virtual and 487 str_l x4, kimage_voffset, x5 // physical mappings 488 489 mov x0, x20 490 bl set_cpu_boot_mode_flag 491 492 // Clear BSS 493 adr_l x0, __bss_start 494 mov x1, xzr 495 adr_l x2, __bss_stop 496 sub x2, x2, x0 497 bl __pi_memset 498 dsb ishst // Make zero page visible to PTW 499 500#if VA_BITS > 48 501 adr_l x8, vabits_actual // Set this early so KASAN early init 502 str x25, [x8] // ... observes the correct value 503 dc civac, x8 // Make visible to booting secondaries 504#endif 505 506#ifdef CONFIG_RANDOMIZE_BASE 507 adrp x5, memstart_offset_seed // Save KASLR linear map seed 508 strh w24, [x5, :lo12:memstart_offset_seed] 509#endif 510#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) 511 bl kasan_early_init 512#endif 513 mov x0, x21 // pass FDT address in x0 514 bl early_fdt_map // Try mapping the FDT early 515 mov x0, x20 // pass the full boot status 516 bl init_feature_override // Parse cpu feature overrides 517#ifdef CONFIG_UNWIND_PATCH_PAC_INTO_SCS 518 bl scs_patch_vmlinux 519#endif 520 mov x0, x20 521 bl finalise_el2 // Prefer VHE if possible 522 ldp x29, x30, [sp], #16 523 bl start_kernel 524 ASM_BUG() 525SYM_FUNC_END(__primary_switched) 526 527/* 528 * end early head section, begin head code that is also used for 529 * hotplug and needs to have the same protections as the text region 530 */ 531 .section ".idmap.text","a" 532 533/* 534 * Starting from EL2 or EL1, configure the CPU to execute at the highest 535 * reachable EL supported by the kernel in a chosen default state. If dropping 536 * from EL2 to EL1, configure EL2 before configuring EL1. 537 * 538 * Since we cannot always rely on ERET synchronizing writes to sysregs (e.g. if 539 * SCTLR_ELx.EOS is clear), we place an ISB prior to ERET. 540 * 541 * Returns either BOOT_CPU_MODE_EL1 or BOOT_CPU_MODE_EL2 in x0 if 542 * booted in EL1 or EL2 respectively, with the top 32 bits containing 543 * potential context flags. These flags are *not* stored in __boot_cpu_mode. 544 * 545 * x0: whether we are being called from the primary boot path with the MMU on 546 */ 547SYM_FUNC_START(init_kernel_el) 548 mrs x1, CurrentEL 549 cmp x1, #CurrentEL_EL2 550 b.eq init_el2 551 552SYM_INNER_LABEL(init_el1, SYM_L_LOCAL) 553 mov_q x0, INIT_SCTLR_EL1_MMU_OFF 554 pre_disable_mmu_workaround 555 msr sctlr_el1, x0 556 isb 557 mov_q x0, INIT_PSTATE_EL1 558 msr spsr_el1, x0 559 msr elr_el1, lr 560 mov w0, #BOOT_CPU_MODE_EL1 561 eret 562 563SYM_INNER_LABEL(init_el2, SYM_L_LOCAL) 564 msr elr_el2, lr 565 566 // clean all HYP code to the PoC if we booted at EL2 with the MMU on 567 cbz x0, 0f 568 adrp x0, __hyp_idmap_text_start 569 adr_l x1, __hyp_text_end 570 adr_l x2, dcache_clean_poc 571 blr x2 5720: 573 mov_q x0, HCR_HOST_NVHE_FLAGS 574 msr hcr_el2, x0 575 isb 576 577 init_el2_state 578 579 /* Hypervisor stub */ 580 adr_l x0, __hyp_stub_vectors 581 msr vbar_el2, x0 582 isb 583 584 mov_q x1, INIT_SCTLR_EL1_MMU_OFF 585 586 /* 587 * Fruity CPUs seem to have HCR_EL2.E2H set to RES1, 588 * making it impossible to start in nVHE mode. Is that 589 * compliant with the architecture? Absolutely not! 590 */ 591 mrs x0, hcr_el2 592 and x0, x0, #HCR_E2H 593 cbz x0, 1f 594 595 /* Set a sane SCTLR_EL1, the VHE way */ 596 pre_disable_mmu_workaround 597 msr_s SYS_SCTLR_EL12, x1 598 mov x2, #BOOT_CPU_FLAG_E2H 599 b 2f 600 6011: 602 pre_disable_mmu_workaround 603 msr sctlr_el1, x1 604 mov x2, xzr 6052: 606 mov w0, #BOOT_CPU_MODE_EL2 607 orr x0, x0, x2 608 eret 609SYM_FUNC_END(init_kernel_el) 610 611 /* 612 * This provides a "holding pen" for platforms to hold all secondary 613 * cores are held until we're ready for them to initialise. 614 */ 615SYM_FUNC_START(secondary_holding_pen) 616 mov x0, xzr 617 bl init_kernel_el // w0=cpu_boot_mode 618 mrs x2, mpidr_el1 619 mov_q x1, MPIDR_HWID_BITMASK 620 and x2, x2, x1 621 adr_l x3, secondary_holding_pen_release 622pen: ldr x4, [x3] 623 cmp x4, x2 624 b.eq secondary_startup 625 wfe 626 b pen 627SYM_FUNC_END(secondary_holding_pen) 628 629 /* 630 * Secondary entry point that jumps straight into the kernel. Only to 631 * be used where CPUs are brought online dynamically by the kernel. 632 */ 633SYM_FUNC_START(secondary_entry) 634 mov x0, xzr 635 bl init_kernel_el // w0=cpu_boot_mode 636 b secondary_startup 637SYM_FUNC_END(secondary_entry) 638 639SYM_FUNC_START_LOCAL(secondary_startup) 640 /* 641 * Common entry point for secondary CPUs. 642 */ 643 mov x20, x0 // preserve boot mode 644 bl __cpu_secondary_check52bitva 645#if VA_BITS > 48 646 ldr_l x0, vabits_actual 647#endif 648 bl __cpu_setup // initialise processor 649 adrp x1, swapper_pg_dir 650 adrp x2, idmap_pg_dir 651 bl __enable_mmu 652 ldr x8, =__secondary_switched 653 br x8 654SYM_FUNC_END(secondary_startup) 655 656 .text 657SYM_FUNC_START_LOCAL(__secondary_switched) 658 mov x0, x20 659 bl set_cpu_boot_mode_flag 660 661 mov x0, x20 662 bl finalise_el2 663 664 str_l xzr, __early_cpu_boot_status, x3 665 adr_l x5, vectors 666 msr vbar_el1, x5 667 isb 668 669 adr_l x0, secondary_data 670 ldr x2, [x0, #CPU_BOOT_TASK] 671 cbz x2, __secondary_too_slow 672 673 init_cpu_task x2, x1, x3 674 675#ifdef CONFIG_ARM64_PTR_AUTH 676 ptrauth_keys_init_cpu x2, x3, x4, x5 677#endif 678 679 bl secondary_start_kernel 680 ASM_BUG() 681SYM_FUNC_END(__secondary_switched) 682 683SYM_FUNC_START_LOCAL(__secondary_too_slow) 684 wfe 685 wfi 686 b __secondary_too_slow 687SYM_FUNC_END(__secondary_too_slow) 688 689/* 690 * Sets the __boot_cpu_mode flag depending on the CPU boot mode passed 691 * in w0. See arch/arm64/include/asm/virt.h for more info. 692 */ 693SYM_FUNC_START_LOCAL(set_cpu_boot_mode_flag) 694 adr_l x1, __boot_cpu_mode 695 cmp w0, #BOOT_CPU_MODE_EL2 696 b.ne 1f 697 add x1, x1, #4 6981: str w0, [x1] // Save CPU boot mode 699 ret 700SYM_FUNC_END(set_cpu_boot_mode_flag) 701 702/* 703 * The booting CPU updates the failed status @__early_cpu_boot_status, 704 * with MMU turned off. 705 * 706 * update_early_cpu_boot_status tmp, status 707 * - Corrupts tmp1, tmp2 708 * - Writes 'status' to __early_cpu_boot_status and makes sure 709 * it is committed to memory. 710 */ 711 712 .macro update_early_cpu_boot_status status, tmp1, tmp2 713 mov \tmp2, #\status 714 adr_l \tmp1, __early_cpu_boot_status 715 str \tmp2, [\tmp1] 716 dmb sy 717 dc ivac, \tmp1 // Invalidate potentially stale cache line 718 .endm 719 720/* 721 * Enable the MMU. 722 * 723 * x0 = SCTLR_EL1 value for turning on the MMU. 724 * x1 = TTBR1_EL1 value 725 * x2 = ID map root table address 726 * 727 * Returns to the caller via x30/lr. This requires the caller to be covered 728 * by the .idmap.text section. 729 * 730 * Checks if the selected granule size is supported by the CPU. 731 * If it isn't, park the CPU 732 */ 733 .section ".idmap.text","a" 734SYM_FUNC_START(__enable_mmu) 735 mrs x3, ID_AA64MMFR0_EL1 736 ubfx x3, x3, #ID_AA64MMFR0_EL1_TGRAN_SHIFT, 4 737 cmp x3, #ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MIN 738 b.lt __no_granule_support 739 cmp x3, #ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MAX 740 b.gt __no_granule_support 741 phys_to_ttbr x2, x2 742 msr ttbr0_el1, x2 // load TTBR0 743 load_ttbr1 x1, x1, x3 744 745 set_sctlr_el1 x0 746 747 ret 748SYM_FUNC_END(__enable_mmu) 749 750SYM_FUNC_START(__cpu_secondary_check52bitva) 751#if VA_BITS > 48 752 ldr_l x0, vabits_actual 753 cmp x0, #52 754 b.ne 2f 755 756 mrs_s x0, SYS_ID_AA64MMFR2_EL1 757 and x0, x0, #(0xf << ID_AA64MMFR2_EL1_VARange_SHIFT) 758 cbnz x0, 2f 759 760 update_early_cpu_boot_status \ 761 CPU_STUCK_IN_KERNEL | CPU_STUCK_REASON_52_BIT_VA, x0, x1 7621: wfe 763 wfi 764 b 1b 765 766#endif 7672: ret 768SYM_FUNC_END(__cpu_secondary_check52bitva) 769 770SYM_FUNC_START_LOCAL(__no_granule_support) 771 /* Indicate that this CPU can't boot and is stuck in the kernel */ 772 update_early_cpu_boot_status \ 773 CPU_STUCK_IN_KERNEL | CPU_STUCK_REASON_NO_GRAN, x1, x2 7741: 775 wfe 776 wfi 777 b 1b 778SYM_FUNC_END(__no_granule_support) 779 780#ifdef CONFIG_RELOCATABLE 781SYM_FUNC_START_LOCAL(__relocate_kernel) 782 /* 783 * Iterate over each entry in the relocation table, and apply the 784 * relocations in place. 785 */ 786 adr_l x9, __rela_start 787 adr_l x10, __rela_end 788 mov_q x11, KIMAGE_VADDR // default virtual offset 789 add x11, x11, x23 // actual virtual offset 790 7910: cmp x9, x10 792 b.hs 1f 793 ldp x12, x13, [x9], #24 794 ldr x14, [x9, #-8] 795 cmp w13, #R_AARCH64_RELATIVE 796 b.ne 0b 797 add x14, x14, x23 // relocate 798 str x14, [x12, x23] 799 b 0b 800 8011: 802#ifdef CONFIG_RELR 803 /* 804 * Apply RELR relocations. 805 * 806 * RELR is a compressed format for storing relative relocations. The 807 * encoded sequence of entries looks like: 808 * [ AAAAAAAA BBBBBBB1 BBBBBBB1 ... AAAAAAAA BBBBBB1 ... ] 809 * 810 * i.e. start with an address, followed by any number of bitmaps. The 811 * address entry encodes 1 relocation. The subsequent bitmap entries 812 * encode up to 63 relocations each, at subsequent offsets following 813 * the last address entry. 814 * 815 * The bitmap entries must have 1 in the least significant bit. The 816 * assumption here is that an address cannot have 1 in lsb. Odd 817 * addresses are not supported. Any odd addresses are stored in the RELA 818 * section, which is handled above. 819 * 820 * Excluding the least significant bit in the bitmap, each non-zero 821 * bit in the bitmap represents a relocation to be applied to 822 * a corresponding machine word that follows the base address 823 * word. The second least significant bit represents the machine 824 * word immediately following the initial address, and each bit 825 * that follows represents the next word, in linear order. As such, 826 * a single bitmap can encode up to 63 relocations in a 64-bit object. 827 * 828 * In this implementation we store the address of the next RELR table 829 * entry in x9, the address being relocated by the current address or 830 * bitmap entry in x13 and the address being relocated by the current 831 * bit in x14. 832 */ 833 adr_l x9, __relr_start 834 adr_l x10, __relr_end 835 8362: cmp x9, x10 837 b.hs 7f 838 ldr x11, [x9], #8 839 tbnz x11, #0, 3f // branch to handle bitmaps 840 add x13, x11, x23 841 ldr x12, [x13] // relocate address entry 842 add x12, x12, x23 843 str x12, [x13], #8 // adjust to start of bitmap 844 b 2b 845 8463: mov x14, x13 8474: lsr x11, x11, #1 848 cbz x11, 6f 849 tbz x11, #0, 5f // skip bit if not set 850 ldr x12, [x14] // relocate bit 851 add x12, x12, x23 852 str x12, [x14] 853 8545: add x14, x14, #8 // move to next bit's address 855 b 4b 856 8576: /* 858 * Move to the next bitmap's address. 8 is the word size, and 63 is the 859 * number of significant bits in a bitmap entry. 860 */ 861 add x13, x13, #(8 * 63) 862 b 2b 863 8647: 865#endif 866 ret 867 868SYM_FUNC_END(__relocate_kernel) 869#endif 870 871SYM_FUNC_START_LOCAL(__primary_switch) 872 adrp x1, reserved_pg_dir 873 adrp x2, init_idmap_pg_dir 874 bl __enable_mmu 875#ifdef CONFIG_RELOCATABLE 876 adrp x23, KERNEL_START 877 and x23, x23, MIN_KIMG_ALIGN - 1 878#ifdef CONFIG_RANDOMIZE_BASE 879 mov x0, x22 880 adrp x1, init_pg_end 881 mov sp, x1 882 mov x29, xzr 883 bl __pi_kaslr_early_init 884 and x24, x0, #SZ_2M - 1 // capture memstart offset seed 885 bic x0, x0, #SZ_2M - 1 886 orr x23, x23, x0 // record kernel offset 887#endif 888#endif 889 bl clear_page_tables 890 bl create_kernel_mapping 891 892 adrp x1, init_pg_dir 893 load_ttbr1 x1, x1, x2 894#ifdef CONFIG_RELOCATABLE 895 bl __relocate_kernel 896#endif 897 ldr x8, =__primary_switched 898 adrp x0, KERNEL_START // __pa(KERNEL_START) 899 br x8 900SYM_FUNC_END(__primary_switch) 901