1/* SPDX-License-Identifier: GPL-2.0 */ 2/* 3 * linux/boot/head.S 4 * 5 * Copyright (C) 1991, 1992, 1993 Linus Torvalds 6 */ 7 8/* 9 * head.S contains the 32-bit startup code. 10 * 11 * NOTE!!! Startup happens at absolute address 0x00001000, which is also where 12 * the page directory will exist. The startup code will be overwritten by 13 * the page directory. [According to comments etc elsewhere on a compressed 14 * kernel it will end up at 0x1000 + 1Mb I hope so as I assume this. - AC] 15 * 16 * Page 0 is deliberately kept safe, since System Management Mode code in 17 * laptops may need to access the BIOS data stored there. This is also 18 * useful for future device drivers that either access the BIOS via VM86 19 * mode. 20 */ 21 22/* 23 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996 24 */ 25 .code32 26 .text 27 28#include <linux/init.h> 29#include <linux/linkage.h> 30#include <asm/segment.h> 31#include <asm/boot.h> 32#include <asm/msr.h> 33#include <asm/processor-flags.h> 34#include <asm/asm-offsets.h> 35#include <asm/bootparam.h> 36#include "pgtable.h" 37 38/* 39 * Locally defined symbols should be marked hidden: 40 */ 41 .hidden _bss 42 .hidden _ebss 43 .hidden _got 44 .hidden _egot 45 46 __HEAD 47 .code32 48SYM_FUNC_START(startup_32) 49 /* 50 * 32bit entry is 0 and it is ABI so immutable! 51 * If we come here directly from a bootloader, 52 * kernel(text+data+bss+brk) ramdisk, zero_page, command line 53 * all need to be under the 4G limit. 54 */ 55 cld 56 cli 57 58/* 59 * Calculate the delta between where we were compiled to run 60 * at and where we were actually loaded at. This can only be done 61 * with a short local call on x86. Nothing else will tell us what 62 * address we are running at. The reserved chunk of the real-mode 63 * data at 0x1e4 (defined as a scratch field) are used as the stack 64 * for this calculation. Only 4 bytes are needed. 65 */ 66 leal (BP_scratch+4)(%esi), %esp 67 call 1f 681: popl %ebp 69 subl $1b, %ebp 70 71 /* Load new GDT with the 64bit segments using 32bit descriptor */ 72 leal gdt(%ebp), %eax 73 movl %eax, 2(%eax) 74 lgdt (%eax) 75 76 /* Load segment registers with our descriptors */ 77 movl $__BOOT_DS, %eax 78 movl %eax, %ds 79 movl %eax, %es 80 movl %eax, %fs 81 movl %eax, %gs 82 movl %eax, %ss 83 84/* setup a stack and make sure cpu supports long mode. */ 85 leal boot_stack_end(%ebp), %esp 86 87 call verify_cpu 88 testl %eax, %eax 89 jnz .Lno_longmode 90 91/* 92 * Compute the delta between where we were compiled to run at 93 * and where the code will actually run at. 94 * 95 * %ebp contains the address we are loaded at by the boot loader and %ebx 96 * contains the address where we should move the kernel image temporarily 97 * for safe in-place decompression. 98 */ 99 100#ifdef CONFIG_RELOCATABLE 101 movl %ebp, %ebx 102 103#ifdef CONFIG_EFI_STUB 104/* 105 * If we were loaded via the EFI LoadImage service, startup_32 will be at an 106 * offset to the start of the space allocated for the image. efi_pe_entry will 107 * set up image_offset to tell us where the image actually starts, so that we 108 * can use the full available buffer. 109 * image_offset = startup_32 - image_base 110 * Otherwise image_offset will be zero and has no effect on the calculations. 111 */ 112 subl image_offset(%ebp), %ebx 113#endif 114 115 movl BP_kernel_alignment(%esi), %eax 116 decl %eax 117 addl %eax, %ebx 118 notl %eax 119 andl %eax, %ebx 120 cmpl $LOAD_PHYSICAL_ADDR, %ebx 121 jae 1f 122#endif 123 movl $LOAD_PHYSICAL_ADDR, %ebx 1241: 125 126 /* Target address to relocate to for decompression */ 127 addl BP_init_size(%esi), %ebx 128 subl $_end, %ebx 129 130/* 131 * Prepare for entering 64 bit mode 132 */ 133 134 /* Enable PAE mode */ 135 movl %cr4, %eax 136 orl $X86_CR4_PAE, %eax 137 movl %eax, %cr4 138 139 /* 140 * Build early 4G boot pagetable 141 */ 142 /* 143 * If SEV is active then set the encryption mask in the page tables. 144 * This will insure that when the kernel is copied and decompressed 145 * it will be done so encrypted. 146 */ 147 call get_sev_encryption_bit 148 xorl %edx, %edx 149 testl %eax, %eax 150 jz 1f 151 subl $32, %eax /* Encryption bit is always above bit 31 */ 152 bts %eax, %edx /* Set encryption mask for page tables */ 1531: 154 155 /* Initialize Page tables to 0 */ 156 leal pgtable(%ebx), %edi 157 xorl %eax, %eax 158 movl $(BOOT_INIT_PGT_SIZE/4), %ecx 159 rep stosl 160 161 /* Build Level 4 */ 162 leal pgtable + 0(%ebx), %edi 163 leal 0x1007 (%edi), %eax 164 movl %eax, 0(%edi) 165 addl %edx, 4(%edi) 166 167 /* Build Level 3 */ 168 leal pgtable + 0x1000(%ebx), %edi 169 leal 0x1007(%edi), %eax 170 movl $4, %ecx 1711: movl %eax, 0x00(%edi) 172 addl %edx, 0x04(%edi) 173 addl $0x00001000, %eax 174 addl $8, %edi 175 decl %ecx 176 jnz 1b 177 178 /* Build Level 2 */ 179 leal pgtable + 0x2000(%ebx), %edi 180 movl $0x00000183, %eax 181 movl $2048, %ecx 1821: movl %eax, 0(%edi) 183 addl %edx, 4(%edi) 184 addl $0x00200000, %eax 185 addl $8, %edi 186 decl %ecx 187 jnz 1b 188 189 /* Enable the boot page tables */ 190 leal pgtable(%ebx), %eax 191 movl %eax, %cr3 192 193 /* Enable Long mode in EFER (Extended Feature Enable Register) */ 194 movl $MSR_EFER, %ecx 195 rdmsr 196 btsl $_EFER_LME, %eax 197 wrmsr 198 199 /* After gdt is loaded */ 200 xorl %eax, %eax 201 lldt %ax 202 movl $__BOOT_TSS, %eax 203 ltr %ax 204 205 /* 206 * Setup for the jump to 64bit mode 207 * 208 * When the jump is performend we will be in long mode but 209 * in 32bit compatibility mode with EFER.LME = 1, CS.L = 0, CS.D = 1 210 * (and in turn EFER.LMA = 1). To jump into 64bit mode we use 211 * the new gdt/idt that has __KERNEL_CS with CS.L = 1. 212 * We place all of the values on our mini stack so lret can 213 * used to perform that far jump. 214 */ 215 pushl $__KERNEL_CS 216 leal startup_64(%ebp), %eax 217#ifdef CONFIG_EFI_MIXED 218 movl efi32_boot_args(%ebp), %edi 219 cmp $0, %edi 220 jz 1f 221 leal efi64_stub_entry(%ebp), %eax 222 movl efi32_boot_args+4(%ebp), %esi 223 movl efi32_boot_args+8(%ebp), %edx // saved bootparams pointer 224 cmpl $0, %edx 225 jnz 1f 226 leal efi_pe_entry(%ebp), %eax 227 movl %edi, %ecx // MS calling convention 228 movl %esi, %edx 2291: 230#endif 231 pushl %eax 232 233 /* Enter paged protected Mode, activating Long Mode */ 234 movl $(X86_CR0_PG | X86_CR0_PE), %eax /* Enable Paging and Protected mode */ 235 movl %eax, %cr0 236 237 /* Jump from 32bit compatibility mode into 64bit mode. */ 238 lret 239SYM_FUNC_END(startup_32) 240 241#ifdef CONFIG_EFI_MIXED 242 .org 0x190 243SYM_FUNC_START(efi32_stub_entry) 244 add $0x4, %esp /* Discard return address */ 245 popl %ecx 246 popl %edx 247 popl %esi 248 249 call 1f 2501: pop %ebp 251 subl $1b, %ebp 252 253 movl %esi, efi32_boot_args+8(%ebp) 254SYM_INNER_LABEL(efi32_pe_stub_entry, SYM_L_LOCAL) 255 movl %ecx, efi32_boot_args(%ebp) 256 movl %edx, efi32_boot_args+4(%ebp) 257 movb $0, efi_is64(%ebp) 258 259 /* Save firmware GDTR and code/data selectors */ 260 sgdtl efi32_boot_gdt(%ebp) 261 movw %cs, efi32_boot_cs(%ebp) 262 movw %ds, efi32_boot_ds(%ebp) 263 264 /* Disable paging */ 265 movl %cr0, %eax 266 btrl $X86_CR0_PG_BIT, %eax 267 movl %eax, %cr0 268 269 jmp startup_32 270SYM_FUNC_END(efi32_stub_entry) 271#endif 272 273 .code64 274 .org 0x200 275SYM_CODE_START(startup_64) 276 /* 277 * 64bit entry is 0x200 and it is ABI so immutable! 278 * We come here either from startup_32 or directly from a 279 * 64bit bootloader. 280 * If we come here from a bootloader, kernel(text+data+bss+brk), 281 * ramdisk, zero_page, command line could be above 4G. 282 * We depend on an identity mapped page table being provided 283 * that maps our entire kernel(text+data+bss+brk), zero page 284 * and command line. 285 */ 286 287 cld 288 cli 289 290 /* Setup data segments. */ 291 xorl %eax, %eax 292 movl %eax, %ds 293 movl %eax, %es 294 movl %eax, %ss 295 movl %eax, %fs 296 movl %eax, %gs 297 298 /* 299 * Compute the decompressed kernel start address. It is where 300 * we were loaded at aligned to a 2M boundary. %rbp contains the 301 * decompressed kernel start address. 302 * 303 * If it is a relocatable kernel then decompress and run the kernel 304 * from load address aligned to 2MB addr, otherwise decompress and 305 * run the kernel from LOAD_PHYSICAL_ADDR 306 * 307 * We cannot rely on the calculation done in 32-bit mode, since we 308 * may have been invoked via the 64-bit entry point. 309 */ 310 311 /* Start with the delta to where the kernel will run at. */ 312#ifdef CONFIG_RELOCATABLE 313 leaq startup_32(%rip) /* - $startup_32 */, %rbp 314 315#ifdef CONFIG_EFI_STUB 316/* 317 * If we were loaded via the EFI LoadImage service, startup_32 will be at an 318 * offset to the start of the space allocated for the image. efi_pe_entry will 319 * set up image_offset to tell us where the image actually starts, so that we 320 * can use the full available buffer. 321 * image_offset = startup_32 - image_base 322 * Otherwise image_offset will be zero and has no effect on the calculations. 323 */ 324 movl image_offset(%rip), %eax 325 subq %rax, %rbp 326#endif 327 328 movl BP_kernel_alignment(%rsi), %eax 329 decl %eax 330 addq %rax, %rbp 331 notq %rax 332 andq %rax, %rbp 333 cmpq $LOAD_PHYSICAL_ADDR, %rbp 334 jae 1f 335#endif 336 movq $LOAD_PHYSICAL_ADDR, %rbp 3371: 338 339 /* Target address to relocate to for decompression */ 340 movl BP_init_size(%rsi), %ebx 341 subl $_end, %ebx 342 addq %rbp, %rbx 343 344 /* Set up the stack */ 345 leaq boot_stack_end(%rbx), %rsp 346 347 /* 348 * paging_prepare() and cleanup_trampoline() below can have GOT 349 * references. Adjust the table with address we are running at. 350 * 351 * Zero RAX for adjust_got: the GOT was not adjusted before; 352 * there's no adjustment to undo. 353 */ 354 xorq %rax, %rax 355 356 /* 357 * Calculate the address the binary is loaded at and use it as 358 * a GOT adjustment. 359 */ 360 call 1f 3611: popq %rdi 362 subq $1b, %rdi 363 364 call .Ladjust_got 365 366 /* 367 * At this point we are in long mode with 4-level paging enabled, 368 * but we might want to enable 5-level paging or vice versa. 369 * 370 * The problem is that we cannot do it directly. Setting or clearing 371 * CR4.LA57 in long mode would trigger #GP. So we need to switch off 372 * long mode and paging first. 373 * 374 * We also need a trampoline in lower memory to switch over from 375 * 4- to 5-level paging for cases when the bootloader puts the kernel 376 * above 4G, but didn't enable 5-level paging for us. 377 * 378 * The same trampoline can be used to switch from 5- to 4-level paging 379 * mode, like when starting 4-level paging kernel via kexec() when 380 * original kernel worked in 5-level paging mode. 381 * 382 * For the trampoline, we need the top page table to reside in lower 383 * memory as we don't have a way to load 64-bit values into CR3 in 384 * 32-bit mode. 385 * 386 * We go though the trampoline even if we don't have to: if we're 387 * already in a desired paging mode. This way the trampoline code gets 388 * tested on every boot. 389 */ 390 391 /* Make sure we have GDT with 32-bit code segment */ 392 leaq gdt64(%rip), %rax 393 addq %rax, 2(%rax) 394 lgdt (%rax) 395 396 /* 397 * paging_prepare() sets up the trampoline and checks if we need to 398 * enable 5-level paging. 399 * 400 * paging_prepare() returns a two-quadword structure which lands 401 * into RDX:RAX: 402 * - Address of the trampoline is returned in RAX. 403 * - Non zero RDX means trampoline needs to enable 5-level 404 * paging. 405 * 406 * RSI holds real mode data and needs to be preserved across 407 * this function call. 408 */ 409 pushq %rsi 410 movq %rsi, %rdi /* real mode address */ 411 call paging_prepare 412 popq %rsi 413 414 /* Save the trampoline address in RCX */ 415 movq %rax, %rcx 416 417 /* 418 * Load the address of trampoline_return() into RDI. 419 * It will be used by the trampoline to return to the main code. 420 */ 421 leaq trampoline_return(%rip), %rdi 422 423 /* Switch to compatibility mode (CS.L = 0 CS.D = 1) via far return */ 424 pushq $__KERNEL32_CS 425 leaq TRAMPOLINE_32BIT_CODE_OFFSET(%rax), %rax 426 pushq %rax 427 lretq 428trampoline_return: 429 /* Restore the stack, the 32-bit trampoline uses its own stack */ 430 leaq boot_stack_end(%rbx), %rsp 431 432 /* 433 * cleanup_trampoline() would restore trampoline memory. 434 * 435 * RDI is address of the page table to use instead of page table 436 * in trampoline memory (if required). 437 * 438 * RSI holds real mode data and needs to be preserved across 439 * this function call. 440 */ 441 pushq %rsi 442 leaq top_pgtable(%rbx), %rdi 443 call cleanup_trampoline 444 popq %rsi 445 446 /* Zero EFLAGS */ 447 pushq $0 448 popfq 449 450 /* 451 * Previously we've adjusted the GOT with address the binary was 452 * loaded at. Now we need to re-adjust for relocation address. 453 * 454 * Calculate the address the binary is loaded at, so that we can 455 * undo the previous GOT adjustment. 456 */ 457 call 1f 4581: popq %rax 459 subq $1b, %rax 460 461 /* The new adjustment is the relocation address */ 462 movq %rbx, %rdi 463 call .Ladjust_got 464 465/* 466 * Copy the compressed kernel to the end of our buffer 467 * where decompression in place becomes safe. 468 */ 469 pushq %rsi 470 leaq (_bss-8)(%rip), %rsi 471 leaq (_bss-8)(%rbx), %rdi 472 movq $_bss /* - $startup_32 */, %rcx 473 shrq $3, %rcx 474 std 475 rep movsq 476 cld 477 popq %rsi 478 479 /* 480 * The GDT may get overwritten either during the copy we just did or 481 * during extract_kernel below. To avoid any issues, repoint the GDTR 482 * to the new copy of the GDT. 483 */ 484 leaq gdt64(%rbx), %rax 485 leaq gdt(%rbx), %rdx 486 movq %rdx, 2(%rax) 487 lgdt (%rax) 488 489/* 490 * Jump to the relocated address. 491 */ 492 leaq .Lrelocated(%rbx), %rax 493 jmp *%rax 494SYM_CODE_END(startup_64) 495 496#ifdef CONFIG_EFI_STUB 497 .org 0x390 498SYM_FUNC_START(efi64_stub_entry) 499SYM_FUNC_START_ALIAS(efi_stub_entry) 500 and $~0xf, %rsp /* realign the stack */ 501 movq %rdx, %rbx /* save boot_params pointer */ 502 call efi_main 503 movq %rbx,%rsi 504 leaq startup_64(%rax), %rax 505 jmp *%rax 506SYM_FUNC_END(efi64_stub_entry) 507SYM_FUNC_END_ALIAS(efi_stub_entry) 508#endif 509 510 .text 511SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated) 512 513/* 514 * Clear BSS (stack is currently empty) 515 */ 516 xorl %eax, %eax 517 leaq _bss(%rip), %rdi 518 leaq _ebss(%rip), %rcx 519 subq %rdi, %rcx 520 shrq $3, %rcx 521 rep stosq 522 523/* 524 * Do the extraction, and jump to the new kernel.. 525 */ 526 pushq %rsi /* Save the real mode argument */ 527 movq %rsi, %rdi /* real mode address */ 528 leaq boot_heap(%rip), %rsi /* malloc area for uncompression */ 529 leaq input_data(%rip), %rdx /* input_data */ 530 movl $z_input_len, %ecx /* input_len */ 531 movq %rbp, %r8 /* output target address */ 532 movl $z_output_len, %r9d /* decompressed length, end of relocs */ 533 call extract_kernel /* returns kernel location in %rax */ 534 popq %rsi 535 536/* 537 * Jump to the decompressed kernel. 538 */ 539 jmp *%rax 540SYM_FUNC_END(.Lrelocated) 541 542/* 543 * Adjust the global offset table 544 * 545 * RAX is the previous adjustment of the table to undo (use 0 if it's the 546 * first time we touch GOT). 547 * RDI is the new adjustment to apply. 548 */ 549.Ladjust_got: 550 /* Walk through the GOT adding the address to the entries */ 551 leaq _got(%rip), %rdx 552 leaq _egot(%rip), %rcx 5531: 554 cmpq %rcx, %rdx 555 jae 2f 556 subq %rax, (%rdx) /* Undo previous adjustment */ 557 addq %rdi, (%rdx) /* Apply the new adjustment */ 558 addq $8, %rdx 559 jmp 1b 5602: 561 ret 562 563 .code32 564/* 565 * This is the 32-bit trampoline that will be copied over to low memory. 566 * 567 * RDI contains the return address (might be above 4G). 568 * ECX contains the base address of the trampoline memory. 569 * Non zero RDX means trampoline needs to enable 5-level paging. 570 */ 571SYM_CODE_START(trampoline_32bit_src) 572 /* Set up data and stack segments */ 573 movl $__KERNEL_DS, %eax 574 movl %eax, %ds 575 movl %eax, %ss 576 577 /* Set up new stack */ 578 leal TRAMPOLINE_32BIT_STACK_END(%ecx), %esp 579 580 /* Disable paging */ 581 movl %cr0, %eax 582 btrl $X86_CR0_PG_BIT, %eax 583 movl %eax, %cr0 584 585 /* Check what paging mode we want to be in after the trampoline */ 586 cmpl $0, %edx 587 jz 1f 588 589 /* We want 5-level paging: don't touch CR3 if it already points to 5-level page tables */ 590 movl %cr4, %eax 591 testl $X86_CR4_LA57, %eax 592 jnz 3f 593 jmp 2f 5941: 595 /* We want 4-level paging: don't touch CR3 if it already points to 4-level page tables */ 596 movl %cr4, %eax 597 testl $X86_CR4_LA57, %eax 598 jz 3f 5992: 600 /* Point CR3 to the trampoline's new top level page table */ 601 leal TRAMPOLINE_32BIT_PGTABLE_OFFSET(%ecx), %eax 602 movl %eax, %cr3 6033: 604 /* Set EFER.LME=1 as a precaution in case hypervsior pulls the rug */ 605 pushl %ecx 606 pushl %edx 607 movl $MSR_EFER, %ecx 608 rdmsr 609 btsl $_EFER_LME, %eax 610 wrmsr 611 popl %edx 612 popl %ecx 613 614 /* Enable PAE and LA57 (if required) paging modes */ 615 movl $X86_CR4_PAE, %eax 616 cmpl $0, %edx 617 jz 1f 618 orl $X86_CR4_LA57, %eax 6191: 620 movl %eax, %cr4 621 622 /* Calculate address of paging_enabled() once we are executing in the trampoline */ 623 leal .Lpaging_enabled - trampoline_32bit_src + TRAMPOLINE_32BIT_CODE_OFFSET(%ecx), %eax 624 625 /* Prepare the stack for far return to Long Mode */ 626 pushl $__KERNEL_CS 627 pushl %eax 628 629 /* Enable paging again */ 630 movl $(X86_CR0_PG | X86_CR0_PE), %eax 631 movl %eax, %cr0 632 633 lret 634SYM_CODE_END(trampoline_32bit_src) 635 636 .code64 637SYM_FUNC_START_LOCAL_NOALIGN(.Lpaging_enabled) 638 /* Return from the trampoline */ 639 jmp *%rdi 640SYM_FUNC_END(.Lpaging_enabled) 641 642 /* 643 * The trampoline code has a size limit. 644 * Make sure we fail to compile if the trampoline code grows 645 * beyond TRAMPOLINE_32BIT_CODE_SIZE bytes. 646 */ 647 .org trampoline_32bit_src + TRAMPOLINE_32BIT_CODE_SIZE 648 649 .code32 650SYM_FUNC_START_LOCAL_NOALIGN(.Lno_longmode) 651 /* This isn't an x86-64 CPU, so hang intentionally, we cannot continue */ 6521: 653 hlt 654 jmp 1b 655SYM_FUNC_END(.Lno_longmode) 656 657#include "../../kernel/verify_cpu.S" 658 659 .data 660SYM_DATA_START_LOCAL(gdt64) 661 .word gdt_end - gdt - 1 662 .quad gdt - gdt64 663SYM_DATA_END(gdt64) 664 .balign 8 665SYM_DATA_START_LOCAL(gdt) 666 .word gdt_end - gdt - 1 667 .long 0 668 .word 0 669 .quad 0x00cf9a000000ffff /* __KERNEL32_CS */ 670 .quad 0x00af9a000000ffff /* __KERNEL_CS */ 671 .quad 0x00cf92000000ffff /* __KERNEL_DS */ 672 .quad 0x0080890000000000 /* TS descriptor */ 673 .quad 0x0000000000000000 /* TS continued */ 674SYM_DATA_END_LABEL(gdt, SYM_L_LOCAL, gdt_end) 675 676#ifdef CONFIG_EFI_STUB 677SYM_DATA(image_offset, .long 0) 678#endif 679 680#ifdef CONFIG_EFI_MIXED 681SYM_DATA_LOCAL(efi32_boot_args, .long 0, 0, 0) 682SYM_DATA(efi_is64, .byte 1) 683 684#define ST32_boottime 60 // offsetof(efi_system_table_32_t, boottime) 685#define BS32_handle_protocol 88 // offsetof(efi_boot_services_32_t, handle_protocol) 686#define LI32_image_base 32 // offsetof(efi_loaded_image_32_t, image_base) 687 688 .text 689 .code32 690SYM_FUNC_START(efi32_pe_entry) 691/* 692 * efi_status_t efi32_pe_entry(efi_handle_t image_handle, 693 * efi_system_table_32_t *sys_table) 694 */ 695 696 pushl %ebp 697 movl %esp, %ebp 698 pushl %eax // dummy push to allocate loaded_image 699 700 pushl %ebx // save callee-save registers 701 pushl %edi 702 703 call verify_cpu // check for long mode support 704 testl %eax, %eax 705 movl $0x80000003, %eax // EFI_UNSUPPORTED 706 jnz 2f 707 708 call 1f 7091: pop %ebx 710 subl $1b, %ebx 711 712 /* Get the loaded image protocol pointer from the image handle */ 713 leal -4(%ebp), %eax 714 pushl %eax // &loaded_image 715 leal loaded_image_proto(%ebx), %eax 716 pushl %eax // pass the GUID address 717 pushl 8(%ebp) // pass the image handle 718 719 /* 720 * Note the alignment of the stack frame. 721 * sys_table 722 * handle <-- 16-byte aligned on entry by ABI 723 * return address 724 * frame pointer 725 * loaded_image <-- local variable 726 * saved %ebx <-- 16-byte aligned here 727 * saved %edi 728 * &loaded_image 729 * &loaded_image_proto 730 * handle <-- 16-byte aligned for call to handle_protocol 731 */ 732 733 movl 12(%ebp), %eax // sys_table 734 movl ST32_boottime(%eax), %eax // sys_table->boottime 735 call *BS32_handle_protocol(%eax) // sys_table->boottime->handle_protocol 736 addl $12, %esp // restore argument space 737 testl %eax, %eax 738 jnz 2f 739 740 movl 8(%ebp), %ecx // image_handle 741 movl 12(%ebp), %edx // sys_table 742 movl -4(%ebp), %esi // loaded_image 743 movl LI32_image_base(%esi), %esi // loaded_image->image_base 744 movl %ebx, %ebp // startup_32 for efi32_pe_stub_entry 745 /* 746 * We need to set the image_offset variable here since startup_32() will 747 * use it before we get to the 64-bit efi_pe_entry() in C code. 748 */ 749 subl %esi, %ebx 750 movl %ebx, image_offset(%ebp) // save image_offset 751 jmp efi32_pe_stub_entry 752 7532: popl %edi // restore callee-save registers 754 popl %ebx 755 leave 756 ret 757SYM_FUNC_END(efi32_pe_entry) 758 759 .section ".rodata" 760 /* EFI loaded image protocol GUID */ 761 .balign 4 762SYM_DATA_START_LOCAL(loaded_image_proto) 763 .long 0x5b1b31a1 764 .word 0x9562, 0x11d2 765 .byte 0x8e, 0x3f, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b 766SYM_DATA_END(loaded_image_proto) 767#endif 768 769/* 770 * Stack and heap for uncompression 771 */ 772 .bss 773 .balign 4 774SYM_DATA_LOCAL(boot_heap, .fill BOOT_HEAP_SIZE, 1, 0) 775 776SYM_DATA_START_LOCAL(boot_stack) 777 .fill BOOT_STACK_SIZE, 1, 0 778SYM_DATA_END_LABEL(boot_stack, SYM_L_LOCAL, boot_stack_end) 779 780/* 781 * Space for page tables (not in .bss so not zeroed) 782 */ 783 .section ".pgtable","aw",@nobits 784 .balign 4096 785SYM_DATA_LOCAL(pgtable, .fill BOOT_PGT_SIZE, 1, 0) 786 787/* 788 * The page table is going to be used instead of page table in the trampoline 789 * memory. 790 */ 791SYM_DATA_LOCAL(top_pgtable, .fill PAGE_SIZE, 1, 0) 792