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 _end 44 45 __HEAD 46 47/* 48 * This macro gives the relative virtual address of X, i.e. the offset of X 49 * from startup_32. This is the same as the link-time virtual address of X, 50 * since startup_32 is at 0, but defining it this way tells the 51 * assembler/linker that we do not want the actual run-time address of X. This 52 * prevents the linker from trying to create unwanted run-time relocation 53 * entries for the reference when the compressed kernel is linked as PIE. 54 * 55 * A reference X(%reg) will result in the link-time VA of X being stored with 56 * the instruction, and a run-time R_X86_64_RELATIVE relocation entry that 57 * adds the 64-bit base address where the kernel is loaded. 58 * 59 * Replacing it with (X-startup_32)(%reg) results in the offset being stored, 60 * and no run-time relocation. 61 * 62 * The macro should be used as a displacement with a base register containing 63 * the run-time address of startup_32 [i.e. rva(X)(%reg)], or as an immediate 64 * [$ rva(X)]. 65 * 66 * This macro can only be used from within the .head.text section, since the 67 * expression requires startup_32 to be in the same section as the code being 68 * assembled. 69 */ 70#define rva(X) ((X) - startup_32) 71 72 .code32 73SYM_FUNC_START(startup_32) 74 /* 75 * 32bit entry is 0 and it is ABI so immutable! 76 * If we come here directly from a bootloader, 77 * kernel(text+data+bss+brk) ramdisk, zero_page, command line 78 * all need to be under the 4G limit. 79 */ 80 cld 81 cli 82 83/* 84 * Calculate the delta between where we were compiled to run 85 * at and where we were actually loaded at. This can only be done 86 * with a short local call on x86. Nothing else will tell us what 87 * address we are running at. The reserved chunk of the real-mode 88 * data at 0x1e4 (defined as a scratch field) are used as the stack 89 * for this calculation. Only 4 bytes are needed. 90 */ 91 leal (BP_scratch+4)(%esi), %esp 92 call 1f 931: popl %ebp 94 subl $ rva(1b), %ebp 95 96 /* Load new GDT with the 64bit segments using 32bit descriptor */ 97 leal rva(gdt)(%ebp), %eax 98 movl %eax, 2(%eax) 99 lgdt (%eax) 100 101 /* Load segment registers with our descriptors */ 102 movl $__BOOT_DS, %eax 103 movl %eax, %ds 104 movl %eax, %es 105 movl %eax, %fs 106 movl %eax, %gs 107 movl %eax, %ss 108 109/* setup a stack and make sure cpu supports long mode. */ 110 leal rva(boot_stack_end)(%ebp), %esp 111 112 call verify_cpu 113 testl %eax, %eax 114 jnz .Lno_longmode 115 116/* 117 * Compute the delta between where we were compiled to run at 118 * and where the code will actually run at. 119 * 120 * %ebp contains the address we are loaded at by the boot loader and %ebx 121 * contains the address where we should move the kernel image temporarily 122 * for safe in-place decompression. 123 */ 124 125#ifdef CONFIG_RELOCATABLE 126 movl %ebp, %ebx 127 128#ifdef CONFIG_EFI_STUB 129/* 130 * If we were loaded via the EFI LoadImage service, startup_32 will be at an 131 * offset to the start of the space allocated for the image. efi_pe_entry will 132 * set up image_offset to tell us where the image actually starts, so that we 133 * can use the full available buffer. 134 * image_offset = startup_32 - image_base 135 * Otherwise image_offset will be zero and has no effect on the calculations. 136 */ 137 subl rva(image_offset)(%ebp), %ebx 138#endif 139 140 movl BP_kernel_alignment(%esi), %eax 141 decl %eax 142 addl %eax, %ebx 143 notl %eax 144 andl %eax, %ebx 145 cmpl $LOAD_PHYSICAL_ADDR, %ebx 146 jae 1f 147#endif 148 movl $LOAD_PHYSICAL_ADDR, %ebx 1491: 150 151 /* Target address to relocate to for decompression */ 152 addl BP_init_size(%esi), %ebx 153 subl $ rva(_end), %ebx 154 155/* 156 * Prepare for entering 64 bit mode 157 */ 158 159 /* Enable PAE mode */ 160 movl %cr4, %eax 161 orl $X86_CR4_PAE, %eax 162 movl %eax, %cr4 163 164 /* 165 * Build early 4G boot pagetable 166 */ 167 /* 168 * If SEV is active then set the encryption mask in the page tables. 169 * This will insure that when the kernel is copied and decompressed 170 * it will be done so encrypted. 171 */ 172 call get_sev_encryption_bit 173 xorl %edx, %edx 174 testl %eax, %eax 175 jz 1f 176 subl $32, %eax /* Encryption bit is always above bit 31 */ 177 bts %eax, %edx /* Set encryption mask for page tables */ 1781: 179 180 /* Initialize Page tables to 0 */ 181 leal rva(pgtable)(%ebx), %edi 182 xorl %eax, %eax 183 movl $(BOOT_INIT_PGT_SIZE/4), %ecx 184 rep stosl 185 186 /* Build Level 4 */ 187 leal rva(pgtable + 0)(%ebx), %edi 188 leal 0x1007 (%edi), %eax 189 movl %eax, 0(%edi) 190 addl %edx, 4(%edi) 191 192 /* Build Level 3 */ 193 leal rva(pgtable + 0x1000)(%ebx), %edi 194 leal 0x1007(%edi), %eax 195 movl $4, %ecx 1961: movl %eax, 0x00(%edi) 197 addl %edx, 0x04(%edi) 198 addl $0x00001000, %eax 199 addl $8, %edi 200 decl %ecx 201 jnz 1b 202 203 /* Build Level 2 */ 204 leal rva(pgtable + 0x2000)(%ebx), %edi 205 movl $0x00000183, %eax 206 movl $2048, %ecx 2071: movl %eax, 0(%edi) 208 addl %edx, 4(%edi) 209 addl $0x00200000, %eax 210 addl $8, %edi 211 decl %ecx 212 jnz 1b 213 214 /* Enable the boot page tables */ 215 leal rva(pgtable)(%ebx), %eax 216 movl %eax, %cr3 217 218 /* Enable Long mode in EFER (Extended Feature Enable Register) */ 219 movl $MSR_EFER, %ecx 220 rdmsr 221 btsl $_EFER_LME, %eax 222 wrmsr 223 224 /* After gdt is loaded */ 225 xorl %eax, %eax 226 lldt %ax 227 movl $__BOOT_TSS, %eax 228 ltr %ax 229 230 /* 231 * Setup for the jump to 64bit mode 232 * 233 * When the jump is performend we will be in long mode but 234 * in 32bit compatibility mode with EFER.LME = 1, CS.L = 0, CS.D = 1 235 * (and in turn EFER.LMA = 1). To jump into 64bit mode we use 236 * the new gdt/idt that has __KERNEL_CS with CS.L = 1. 237 * We place all of the values on our mini stack so lret can 238 * used to perform that far jump. 239 */ 240 leal rva(startup_64)(%ebp), %eax 241#ifdef CONFIG_EFI_MIXED 242 movl rva(efi32_boot_args)(%ebp), %edi 243 cmp $0, %edi 244 jz 1f 245 leal rva(efi64_stub_entry)(%ebp), %eax 246 movl rva(efi32_boot_args+4)(%ebp), %esi 247 movl rva(efi32_boot_args+8)(%ebp), %edx // saved bootparams pointer 248 cmpl $0, %edx 249 jnz 1f 250 /* 251 * efi_pe_entry uses MS calling convention, which requires 32 bytes of 252 * shadow space on the stack even if all arguments are passed in 253 * registers. We also need an additional 8 bytes for the space that 254 * would be occupied by the return address, and this also results in 255 * the correct stack alignment for entry. 256 */ 257 subl $40, %esp 258 leal rva(efi_pe_entry)(%ebp), %eax 259 movl %edi, %ecx // MS calling convention 260 movl %esi, %edx 2611: 262#endif 263 pushl $__KERNEL_CS 264 pushl %eax 265 266 /* Enter paged protected Mode, activating Long Mode */ 267 movl $(X86_CR0_PG | X86_CR0_PE), %eax /* Enable Paging and Protected mode */ 268 movl %eax, %cr0 269 270 /* Jump from 32bit compatibility mode into 64bit mode. */ 271 lret 272SYM_FUNC_END(startup_32) 273 274#ifdef CONFIG_EFI_MIXED 275 .org 0x190 276SYM_FUNC_START(efi32_stub_entry) 277 add $0x4, %esp /* Discard return address */ 278 popl %ecx 279 popl %edx 280 popl %esi 281 282 call 1f 2831: pop %ebp 284 subl $ rva(1b), %ebp 285 286 movl %esi, rva(efi32_boot_args+8)(%ebp) 287SYM_INNER_LABEL(efi32_pe_stub_entry, SYM_L_LOCAL) 288 movl %ecx, rva(efi32_boot_args)(%ebp) 289 movl %edx, rva(efi32_boot_args+4)(%ebp) 290 movb $0, rva(efi_is64)(%ebp) 291 292 /* Save firmware GDTR and code/data selectors */ 293 sgdtl rva(efi32_boot_gdt)(%ebp) 294 movw %cs, rva(efi32_boot_cs)(%ebp) 295 movw %ds, rva(efi32_boot_ds)(%ebp) 296 297 /* Disable paging */ 298 movl %cr0, %eax 299 btrl $X86_CR0_PG_BIT, %eax 300 movl %eax, %cr0 301 302 jmp startup_32 303SYM_FUNC_END(efi32_stub_entry) 304#endif 305 306 .code64 307 .org 0x200 308SYM_CODE_START(startup_64) 309 /* 310 * 64bit entry is 0x200 and it is ABI so immutable! 311 * We come here either from startup_32 or directly from a 312 * 64bit bootloader. 313 * If we come here from a bootloader, kernel(text+data+bss+brk), 314 * ramdisk, zero_page, command line could be above 4G. 315 * We depend on an identity mapped page table being provided 316 * that maps our entire kernel(text+data+bss+brk), zero page 317 * and command line. 318 */ 319 320 cld 321 cli 322 323 /* Setup data segments. */ 324 xorl %eax, %eax 325 movl %eax, %ds 326 movl %eax, %es 327 movl %eax, %ss 328 movl %eax, %fs 329 movl %eax, %gs 330 331 /* 332 * Compute the decompressed kernel start address. It is where 333 * we were loaded at aligned to a 2M boundary. %rbp contains the 334 * decompressed kernel start address. 335 * 336 * If it is a relocatable kernel then decompress and run the kernel 337 * from load address aligned to 2MB addr, otherwise decompress and 338 * run the kernel from LOAD_PHYSICAL_ADDR 339 * 340 * We cannot rely on the calculation done in 32-bit mode, since we 341 * may have been invoked via the 64-bit entry point. 342 */ 343 344 /* Start with the delta to where the kernel will run at. */ 345#ifdef CONFIG_RELOCATABLE 346 leaq startup_32(%rip) /* - $startup_32 */, %rbp 347 348#ifdef CONFIG_EFI_STUB 349/* 350 * If we were loaded via the EFI LoadImage service, startup_32 will be at an 351 * offset to the start of the space allocated for the image. efi_pe_entry will 352 * set up image_offset to tell us where the image actually starts, so that we 353 * can use the full available buffer. 354 * image_offset = startup_32 - image_base 355 * Otherwise image_offset will be zero and has no effect on the calculations. 356 */ 357 movl image_offset(%rip), %eax 358 subq %rax, %rbp 359#endif 360 361 movl BP_kernel_alignment(%rsi), %eax 362 decl %eax 363 addq %rax, %rbp 364 notq %rax 365 andq %rax, %rbp 366 cmpq $LOAD_PHYSICAL_ADDR, %rbp 367 jae 1f 368#endif 369 movq $LOAD_PHYSICAL_ADDR, %rbp 3701: 371 372 /* Target address to relocate to for decompression */ 373 movl BP_init_size(%rsi), %ebx 374 subl $ rva(_end), %ebx 375 addq %rbp, %rbx 376 377 /* Set up the stack */ 378 leaq rva(boot_stack_end)(%rbx), %rsp 379 380 /* 381 * At this point we are in long mode with 4-level paging enabled, 382 * but we might want to enable 5-level paging or vice versa. 383 * 384 * The problem is that we cannot do it directly. Setting or clearing 385 * CR4.LA57 in long mode would trigger #GP. So we need to switch off 386 * long mode and paging first. 387 * 388 * We also need a trampoline in lower memory to switch over from 389 * 4- to 5-level paging for cases when the bootloader puts the kernel 390 * above 4G, but didn't enable 5-level paging for us. 391 * 392 * The same trampoline can be used to switch from 5- to 4-level paging 393 * mode, like when starting 4-level paging kernel via kexec() when 394 * original kernel worked in 5-level paging mode. 395 * 396 * For the trampoline, we need the top page table to reside in lower 397 * memory as we don't have a way to load 64-bit values into CR3 in 398 * 32-bit mode. 399 * 400 * We go though the trampoline even if we don't have to: if we're 401 * already in a desired paging mode. This way the trampoline code gets 402 * tested on every boot. 403 */ 404 405 /* Make sure we have GDT with 32-bit code segment */ 406 leaq gdt64(%rip), %rax 407 addq %rax, 2(%rax) 408 lgdt (%rax) 409 410 /* Reload CS so IRET returns to a CS actually in the GDT */ 411 pushq $__KERNEL_CS 412 leaq .Lon_kernel_cs(%rip), %rax 413 pushq %rax 414 lretq 415 416.Lon_kernel_cs: 417 418 /* 419 * paging_prepare() sets up the trampoline and checks if we need to 420 * enable 5-level paging. 421 * 422 * paging_prepare() returns a two-quadword structure which lands 423 * into RDX:RAX: 424 * - Address of the trampoline is returned in RAX. 425 * - Non zero RDX means trampoline needs to enable 5-level 426 * paging. 427 * 428 * RSI holds real mode data and needs to be preserved across 429 * this function call. 430 */ 431 pushq %rsi 432 movq %rsi, %rdi /* real mode address */ 433 call paging_prepare 434 popq %rsi 435 436 /* Save the trampoline address in RCX */ 437 movq %rax, %rcx 438 439 /* 440 * Load the address of trampoline_return() into RDI. 441 * It will be used by the trampoline to return to the main code. 442 */ 443 leaq trampoline_return(%rip), %rdi 444 445 /* Switch to compatibility mode (CS.L = 0 CS.D = 1) via far return */ 446 pushq $__KERNEL32_CS 447 leaq TRAMPOLINE_32BIT_CODE_OFFSET(%rax), %rax 448 pushq %rax 449 lretq 450trampoline_return: 451 /* Restore the stack, the 32-bit trampoline uses its own stack */ 452 leaq rva(boot_stack_end)(%rbx), %rsp 453 454 /* 455 * cleanup_trampoline() would restore trampoline memory. 456 * 457 * RDI is address of the page table to use instead of page table 458 * in trampoline memory (if required). 459 * 460 * RSI holds real mode data and needs to be preserved across 461 * this function call. 462 */ 463 pushq %rsi 464 leaq rva(top_pgtable)(%rbx), %rdi 465 call cleanup_trampoline 466 popq %rsi 467 468 /* Zero EFLAGS */ 469 pushq $0 470 popfq 471 472/* 473 * Copy the compressed kernel to the end of our buffer 474 * where decompression in place becomes safe. 475 */ 476 pushq %rsi 477 leaq (_bss-8)(%rip), %rsi 478 leaq rva(_bss-8)(%rbx), %rdi 479 movl $(_bss - startup_32), %ecx 480 shrl $3, %ecx 481 std 482 rep movsq 483 cld 484 popq %rsi 485 486 /* 487 * The GDT may get overwritten either during the copy we just did or 488 * during extract_kernel below. To avoid any issues, repoint the GDTR 489 * to the new copy of the GDT. 490 */ 491 leaq rva(gdt64)(%rbx), %rax 492 leaq rva(gdt)(%rbx), %rdx 493 movq %rdx, 2(%rax) 494 lgdt (%rax) 495 496/* 497 * Jump to the relocated address. 498 */ 499 leaq rva(.Lrelocated)(%rbx), %rax 500 jmp *%rax 501SYM_CODE_END(startup_64) 502 503#ifdef CONFIG_EFI_STUB 504 .org 0x390 505SYM_FUNC_START(efi64_stub_entry) 506SYM_FUNC_START_ALIAS(efi_stub_entry) 507 and $~0xf, %rsp /* realign the stack */ 508 movq %rdx, %rbx /* save boot_params pointer */ 509 call efi_main 510 movq %rbx,%rsi 511 leaq rva(startup_64)(%rax), %rax 512 jmp *%rax 513SYM_FUNC_END(efi64_stub_entry) 514SYM_FUNC_END_ALIAS(efi_stub_entry) 515#endif 516 517 .text 518SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated) 519 520/* 521 * Clear BSS (stack is currently empty) 522 */ 523 xorl %eax, %eax 524 leaq _bss(%rip), %rdi 525 leaq _ebss(%rip), %rcx 526 subq %rdi, %rcx 527 shrq $3, %rcx 528 rep stosq 529 530/* 531 * Do the extraction, and jump to the new kernel.. 532 */ 533 pushq %rsi /* Save the real mode argument */ 534 movq %rsi, %rdi /* real mode address */ 535 leaq boot_heap(%rip), %rsi /* malloc area for uncompression */ 536 leaq input_data(%rip), %rdx /* input_data */ 537 movl input_len(%rip), %ecx /* input_len */ 538 movq %rbp, %r8 /* output target address */ 539 movl output_len(%rip), %r9d /* decompressed length, end of relocs */ 540 call extract_kernel /* returns kernel location in %rax */ 541 popq %rsi 542 543/* 544 * Jump to the decompressed kernel. 545 */ 546 jmp *%rax 547SYM_FUNC_END(.Lrelocated) 548 549 .code32 550/* 551 * This is the 32-bit trampoline that will be copied over to low memory. 552 * 553 * RDI contains the return address (might be above 4G). 554 * ECX contains the base address of the trampoline memory. 555 * Non zero RDX means trampoline needs to enable 5-level paging. 556 */ 557SYM_CODE_START(trampoline_32bit_src) 558 /* Set up data and stack segments */ 559 movl $__KERNEL_DS, %eax 560 movl %eax, %ds 561 movl %eax, %ss 562 563 /* Set up new stack */ 564 leal TRAMPOLINE_32BIT_STACK_END(%ecx), %esp 565 566 /* Disable paging */ 567 movl %cr0, %eax 568 btrl $X86_CR0_PG_BIT, %eax 569 movl %eax, %cr0 570 571 /* Check what paging mode we want to be in after the trampoline */ 572 cmpl $0, %edx 573 jz 1f 574 575 /* We want 5-level paging: don't touch CR3 if it already points to 5-level page tables */ 576 movl %cr4, %eax 577 testl $X86_CR4_LA57, %eax 578 jnz 3f 579 jmp 2f 5801: 581 /* We want 4-level paging: don't touch CR3 if it already points to 4-level page tables */ 582 movl %cr4, %eax 583 testl $X86_CR4_LA57, %eax 584 jz 3f 5852: 586 /* Point CR3 to the trampoline's new top level page table */ 587 leal TRAMPOLINE_32BIT_PGTABLE_OFFSET(%ecx), %eax 588 movl %eax, %cr3 5893: 590 /* Set EFER.LME=1 as a precaution in case hypervsior pulls the rug */ 591 pushl %ecx 592 pushl %edx 593 movl $MSR_EFER, %ecx 594 rdmsr 595 btsl $_EFER_LME, %eax 596 wrmsr 597 popl %edx 598 popl %ecx 599 600 /* Enable PAE and LA57 (if required) paging modes */ 601 movl $X86_CR4_PAE, %eax 602 cmpl $0, %edx 603 jz 1f 604 orl $X86_CR4_LA57, %eax 6051: 606 movl %eax, %cr4 607 608 /* Calculate address of paging_enabled() once we are executing in the trampoline */ 609 leal .Lpaging_enabled - trampoline_32bit_src + TRAMPOLINE_32BIT_CODE_OFFSET(%ecx), %eax 610 611 /* Prepare the stack for far return to Long Mode */ 612 pushl $__KERNEL_CS 613 pushl %eax 614 615 /* Enable paging again */ 616 movl $(X86_CR0_PG | X86_CR0_PE), %eax 617 movl %eax, %cr0 618 619 lret 620SYM_CODE_END(trampoline_32bit_src) 621 622 .code64 623SYM_FUNC_START_LOCAL_NOALIGN(.Lpaging_enabled) 624 /* Return from the trampoline */ 625 jmp *%rdi 626SYM_FUNC_END(.Lpaging_enabled) 627 628 /* 629 * The trampoline code has a size limit. 630 * Make sure we fail to compile if the trampoline code grows 631 * beyond TRAMPOLINE_32BIT_CODE_SIZE bytes. 632 */ 633 .org trampoline_32bit_src + TRAMPOLINE_32BIT_CODE_SIZE 634 635 .code32 636SYM_FUNC_START_LOCAL_NOALIGN(.Lno_longmode) 637 /* This isn't an x86-64 CPU, so hang intentionally, we cannot continue */ 6381: 639 hlt 640 jmp 1b 641SYM_FUNC_END(.Lno_longmode) 642 643#include "../../kernel/verify_cpu.S" 644 645 .data 646SYM_DATA_START_LOCAL(gdt64) 647 .word gdt_end - gdt - 1 648 .quad gdt - gdt64 649SYM_DATA_END(gdt64) 650 .balign 8 651SYM_DATA_START_LOCAL(gdt) 652 .word gdt_end - gdt - 1 653 .long 0 654 .word 0 655 .quad 0x00cf9a000000ffff /* __KERNEL32_CS */ 656 .quad 0x00af9a000000ffff /* __KERNEL_CS */ 657 .quad 0x00cf92000000ffff /* __KERNEL_DS */ 658 .quad 0x0080890000000000 /* TS descriptor */ 659 .quad 0x0000000000000000 /* TS continued */ 660SYM_DATA_END_LABEL(gdt, SYM_L_LOCAL, gdt_end) 661 662#ifdef CONFIG_EFI_STUB 663SYM_DATA(image_offset, .long 0) 664#endif 665 666#ifdef CONFIG_EFI_MIXED 667SYM_DATA_LOCAL(efi32_boot_args, .long 0, 0, 0) 668SYM_DATA(efi_is64, .byte 1) 669 670#define ST32_boottime 60 // offsetof(efi_system_table_32_t, boottime) 671#define BS32_handle_protocol 88 // offsetof(efi_boot_services_32_t, handle_protocol) 672#define LI32_image_base 32 // offsetof(efi_loaded_image_32_t, image_base) 673 674 __HEAD 675 .code32 676SYM_FUNC_START(efi32_pe_entry) 677/* 678 * efi_status_t efi32_pe_entry(efi_handle_t image_handle, 679 * efi_system_table_32_t *sys_table) 680 */ 681 682 pushl %ebp 683 movl %esp, %ebp 684 pushl %eax // dummy push to allocate loaded_image 685 686 pushl %ebx // save callee-save registers 687 pushl %edi 688 689 call verify_cpu // check for long mode support 690 testl %eax, %eax 691 movl $0x80000003, %eax // EFI_UNSUPPORTED 692 jnz 2f 693 694 call 1f 6951: pop %ebx 696 subl $ rva(1b), %ebx 697 698 /* Get the loaded image protocol pointer from the image handle */ 699 leal -4(%ebp), %eax 700 pushl %eax // &loaded_image 701 leal rva(loaded_image_proto)(%ebx), %eax 702 pushl %eax // pass the GUID address 703 pushl 8(%ebp) // pass the image handle 704 705 /* 706 * Note the alignment of the stack frame. 707 * sys_table 708 * handle <-- 16-byte aligned on entry by ABI 709 * return address 710 * frame pointer 711 * loaded_image <-- local variable 712 * saved %ebx <-- 16-byte aligned here 713 * saved %edi 714 * &loaded_image 715 * &loaded_image_proto 716 * handle <-- 16-byte aligned for call to handle_protocol 717 */ 718 719 movl 12(%ebp), %eax // sys_table 720 movl ST32_boottime(%eax), %eax // sys_table->boottime 721 call *BS32_handle_protocol(%eax) // sys_table->boottime->handle_protocol 722 addl $12, %esp // restore argument space 723 testl %eax, %eax 724 jnz 2f 725 726 movl 8(%ebp), %ecx // image_handle 727 movl 12(%ebp), %edx // sys_table 728 movl -4(%ebp), %esi // loaded_image 729 movl LI32_image_base(%esi), %esi // loaded_image->image_base 730 movl %ebx, %ebp // startup_32 for efi32_pe_stub_entry 731 /* 732 * We need to set the image_offset variable here since startup_32() will 733 * use it before we get to the 64-bit efi_pe_entry() in C code. 734 */ 735 subl %esi, %ebx 736 movl %ebx, rva(image_offset)(%ebp) // save image_offset 737 jmp efi32_pe_stub_entry 738 7392: popl %edi // restore callee-save registers 740 popl %ebx 741 leave 742 ret 743SYM_FUNC_END(efi32_pe_entry) 744 745 .section ".rodata" 746 /* EFI loaded image protocol GUID */ 747 .balign 4 748SYM_DATA_START_LOCAL(loaded_image_proto) 749 .long 0x5b1b31a1 750 .word 0x9562, 0x11d2 751 .byte 0x8e, 0x3f, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b 752SYM_DATA_END(loaded_image_proto) 753#endif 754 755/* 756 * Stack and heap for uncompression 757 */ 758 .bss 759 .balign 4 760SYM_DATA_LOCAL(boot_heap, .fill BOOT_HEAP_SIZE, 1, 0) 761 762SYM_DATA_START_LOCAL(boot_stack) 763 .fill BOOT_STACK_SIZE, 1, 0 764 .balign 16 765SYM_DATA_END_LABEL(boot_stack, SYM_L_LOCAL, boot_stack_end) 766 767/* 768 * Space for page tables (not in .bss so not zeroed) 769 */ 770 .section ".pgtable","aw",@nobits 771 .balign 4096 772SYM_DATA_LOCAL(pgtable, .fill BOOT_PGT_SIZE, 1, 0) 773 774/* 775 * The page table is going to be used instead of page table in the trampoline 776 * memory. 777 */ 778SYM_DATA_LOCAL(top_pgtable, .fill PAGE_SIZE, 1, 0) 779