mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 19:43:32 +00:00
186 lines
7.4 KiB
C
186 lines
7.4 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2021 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/bits/bits.h"
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#include "libc/dce.h"
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#include "libc/macros.internal.h"
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#include "libc/nt/efi.h"
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#include "libc/nt/thunk/msabi.h"
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#include "libc/runtime/e820.internal.h"
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#include "libc/runtime/internal.h"
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#include "libc/runtime/pc.internal.h"
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#include "libc/runtime/runtime.h"
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#include "libc/str/str.h"
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/* TODO: Why can't we change CR3? Could it really need PML5T? */
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/* TODO: Why does QEMU in UEFI mode take ten seconds to boot? */
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struct EfiArgs {
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char *Args[0x400 / sizeof(char *)];
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char ArgBlock[0xC00];
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};
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static const EFI_GUID kEfiLoadedImageProtocol = LOADED_IMAGE_PROTOCOL;
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/**
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* EFI Application Entrypoint.
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*
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* This entrypoint is mutually exclusive from WinMain since
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* Windows apps and EFI apps use the same PE binary format.
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* So if you want to trade away Windows so that you can use
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* UEFI instead of the normal BIOS boot process, do this:
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*
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* STATIC_YOINK("EfiMain");
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* int main() { ... }
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*
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* You can use QEMU to test this, but please note that UEFI
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* goes thousands of times slower than the normal BIOS boot
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*
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* qemu-system-x86_64 \
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* -bios OVMF.fd \
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* -nographic \
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* -net none \
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* -drive format=raw,file=fat:rw:o/tool/viz
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* FS0:
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* deathstar.com
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*
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* @see libc/dce.h
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*/
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__msabi noasan EFI_STATUS EfiMain(EFI_HANDLE ImageHandle,
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EFI_SYSTEM_TABLE *SystemTable) {
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int type, x87cw;
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struct mman *mm;
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uint32_t DescVersion;
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uintptr_t i, j, MapSize;
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struct EfiArgs *ArgBlock;
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EFI_LOADED_IMAGE *ImgInfo;
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EFI_MEMORY_DESCRIPTOR *Map;
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uintptr_t Args, MapKey, DescSize;
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uint64_t p, pe, cr4, *m, *pd, *sp, *pml4t, *pdt1, *pdt2, *pdpt1, *pdpt2;
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extern char __os asm("__hostos");
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__os = METAL;
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/*
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* Allocates and clears PC-compatible memory and copies image.
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*/
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SystemTable->BootServices->AllocatePages(
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AllocateAddress, EfiConventionalMemory,
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MAX(2 * 1024 * 1024, 1024 * 1024 + (_end - _base)) / 4096, 0);
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SystemTable->BootServices->SetMem(0, 0x80000, 0);
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SystemTable->BootServices->CopyMem((void *)(1024 * 1024), _base,
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_end - _base);
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/*
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* Converts UEFI shell arguments to argv.
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*/
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ArgBlock = (struct EfiArgs *)0x7e000;
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SystemTable->BootServices->HandleProtocol(ImageHandle,
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&kEfiLoadedImageProtocol, &ImgInfo);
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Args = GetDosArgv(ImgInfo->LoadOptions, ArgBlock->ArgBlock,
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sizeof(ArgBlock->ArgBlock), ArgBlock->Args,
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ARRAYLEN(ArgBlock->Args));
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/*
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* Asks UEFI which parts of our RAM we're allowed to use.
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*/
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Map = NULL;
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MapSize = 0;
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SystemTable->BootServices->GetMemoryMap(&MapSize, Map, &MapKey, &DescSize,
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&DescVersion);
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SystemTable->BootServices->AllocatePool(EfiLoaderData, MapSize, Map);
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SystemTable->BootServices->GetMemoryMap(&MapSize, Map, &MapKey, &DescSize,
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&DescVersion);
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asm("xor\t%0,%0" : "=r"(mm)); /* gcc assumes null isn't mapped */
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for (j = i = 0; i < MapSize / sizeof(EFI_MEMORY_DESCRIPTOR); ++i) {
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if (Map[i].Type != EfiConventionalMemory) continue;
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mm->e820[j].addr = Map[i].PhysicalStart;
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mm->e820[j].size = Map[i].NumberOfPages * 4096;
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mm->e820[j].type = kMemoryUsable;
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++j;
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}
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SystemTable->BootServices->FreePool(Map);
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/*
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* Sets up page tables.
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*/
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pd = (uint64_t *)0x79000;
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pdt1 = (uint64_t *)0x7b000;
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pdt2 = (uint64_t *)0x7a000;
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pdpt1 = (uint64_t *)0x7d000;
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pdpt2 = (uint64_t *)0x7c000;
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pml4t = (uint64_t *)0x7e000;
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for (i = 0; i < 512; ++i) {
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pd[i] = 0x1000 * i + PAGE_V + PAGE_RW;
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}
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pdt1[0] = (intptr_t)pd + PAGE_V + PAGE_RW;
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pdt2[0] = (intptr_t)pd + PAGE_V + PAGE_RW;
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pdpt1[0] = (intptr_t)pdt1 + PAGE_V + PAGE_RW;
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pdpt2[0] = (intptr_t)pdt2 + PAGE_V + PAGE_RW;
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pml4t[0] = (intptr_t)pdpt1 + PAGE_V + PAGE_RW;
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pml4t[256] = (intptr_t)pdpt2 + PAGE_V + PAGE_RW;
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__map_phdrs(mm, pml4t, 1024 * 1024);
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/*
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* Asks UEFI to handover control?
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*/
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SystemTable->BootServices->ExitBootServices(ImageHandle, MapKey);
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/*
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* Launches program.
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*/
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asm volatile("fldcw\t%3\n\t"
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"mov\t%4,%%cr3\n\t"
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".weak\tape_stack_vaddr\n\t"
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".weak\tape_stack_memsz\n\t"
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"movabs\t$ape_stack_vaddr,%%rsp\n\t"
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"add\t$ape_stack_memsz,%%rsp\n\t"
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"push\t$0\n\t" /* auxv[1][1] */
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"push\t$0\n\t" /* auxv[1][0] */
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"push\t(%1)\n\t" /* auxv[0][1] */
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"push\t$31\n\t" /* auxv[0][0] AT_EXECFN */
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"push\t$0\n\t" /* envp[0] */
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"sub\t%2,%%rsp\n\t"
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"mov\t%%rsp,%%rdi\n\t"
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"rep movsb\n\t" /* argv */
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"push\t%0\n\t" /* argc */
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"xor\t%%edi,%%edi\n\t"
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"xor\t%%eax,%%eax\n\t"
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"xor\t%%ebx,%%ebx\n\t"
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"xor\t%%ecx,%%ecx\n\t"
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"xor\t%%edx,%%edx\n\t"
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"xor\t%%edi,%%edi\n\t"
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"xor\t%%esi,%%esi\n\t"
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"xor\t%%ebp,%%ebp\n\t"
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"xor\t%%r8d,%%r8d\n\t"
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"xor\t%%r9d,%%r9d\n\t"
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"xor\t%%r10d,%%r10d\n\t"
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"xor\t%%r11d,%%r11d\n\t"
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"xor\t%%r12d,%%r12d\n\t"
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"xor\t%%r13d,%%r13d\n\t"
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"xor\t%%r14d,%%r14d\n\t"
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"xor\t%%r15d,%%r15d\n\t"
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".weak\t_start\n\t"
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"jmp\t_start"
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: /* no outputs */
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: "a"(Args), "S"(ArgBlock->Args), "c"((Args + 1) * 8),
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"m"(x87cw), "r"(pml4t)
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: "memory");
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unreachable;
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}
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