text: /*
   * crt_x86_64.c
   *
   * Copyright (C) 2021 bzt (bztsrc@gitlab)
   *
   * Permission is hereby granted, free of charge, to any person
   * obtaining a copy of this software and associated documentation
   * files (the "Software"), to deal in the Software without
   * restriction, including without limitation the rights to use, copy,
   * modify, merge, publish, distribute, sublicense, and/or sell copies
   * of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be
   * included in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
   * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
   * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   * DEALINGS IN THE SOFTWARE.
   *
   * This file is part of the POSIX-UEFI package.
   * @brief C runtime, bootstraps an EFI application to call standard main()
   *
   */
  
  #include <uefi.h>
  
  /* this is implemented by the application */
  extern int main(int argc, char_t **argv);
  
  /* definitions for elf relocations */
  typedef uint64_t Elf64_Xword;
  typedef	int64_t  Elf64_Sxword;
  typedef uint64_t Elf64_Addr;
  typedef struct
  {
    Elf64_Sxword  d_tag;              /* Dynamic entry type */
    union
      {
        Elf64_Xword d_val;            /* Integer value */
        Elf64_Addr d_ptr;             /* Address value */
      } d_un;
  } Elf64_Dyn;
  #define DT_NULL             0       /* Marks end of dynamic section */
  #define DT_RELA             7       /* Address of Rela relocs */
  #define DT_RELASZ           8       /* Total size of Rela relocs */
  #define DT_RELAENT          9       /* Size of one Rela reloc */
  typedef struct
  {
    Elf64_Addr    r_offset;           /* Address */
    Elf64_Xword   r_info;             /* Relocation type and symbol index */
  } Elf64_Rel;
  #define ELF64_R_TYPE(i)     ((i) & 0xffffffff)
  #define R_X86_64_RELATIVE   8       /* Adjust by program base */
  
  /* globals to store system table pointers */
  efi_handle_t IM = NULL;
  efi_system_table_t *ST = NULL;
  efi_boot_services_t *BS = NULL;
  efi_runtime_services_t *RT = NULL;
  efi_loaded_image_protocol_t *LIP = NULL;
  #ifndef UEFI_NO_UTF8
  char *__argvutf8 = NULL;
  #endif
  
  /* we only need one .o file, so use inline Assembly here */
  void bootstrap()
  {
      __asm__ __volatile__ (
      /* call init in C */
      "	.align 4\n"
  #ifndef __clang__
      "	.globl _start\n"
      "_start:\n"
      "	lea ImageBase(%rip), %rdi\n"
      "	lea _DYNAMIC(%rip), %rsi\n"
      "	call uefi_init\n"
      "	ret\n"
  
      /* fake a relocation record, so that EFI won't complain */
      " 	.data\n"
      "dummy:	.long	0\n"
      " 	.section .reloc, \"a\"\n"
      "label1:\n"
      "	.long	dummy-label1\n"
      " 	.long	10\n"
      "    .word 0\n"
      ".text\n"
  #else
      "	.globl __chkstk\n"
      "__chkstk:\n"
      "	ret\n"
  #endif
      );
  
      /* setjmp and longjmp */
      __asm__ __volatile__ (
      "	.globl	setjmp\n"
      "setjmp:\n"
      "	pop	%rsi\n"
      "	movq	%rbx,0x00(%rdi)\n"
      "	movq	%rsp,0x08(%rdi)\n"
      "	push	%rsi\n"
      "	movq	%rbp,0x10(%rdi)\n"
      "	movq	%r12,0x18(%rdi)\n"
      "	movq	%r13,0x20(%rdi)\n"
      "	movq	%r14,0x28(%rdi)\n"
      "	movq	%r15,0x30(%rdi)\n"
      "	movq	%rsi,0x38(%rdi)\n"
      "	xor	%rax,%rax\n"
      "	ret\n"
      );
      __asm__ __volatile__ (
      "	.globl	longjmp\n"
      "longjmp:\n"
      "	movl	%esi, %eax\n"
      "	movq	0x00(%rdi), %rbx\n"
      "	movq	0x08(%rdi), %rsp\n"
      "	movq	0x10(%rdi), %rbp\n"
      "	movq	0x18(%rdi), %r12\n"
      "	movq	0x20(%rdi), %r13\n"
      "	movq	0x28(%rdi), %r14\n"
      "	movq	0x30(%rdi), %r15\n"
      "	xor	%rdx,%rdx\n"
      "	mov	$1,%rcx\n"
      "	cmp	%rax,%rdx\n"
      "	cmove	%rcx,%rax\n"
      "	jmp	*0x38(%rdi)\n"
      );
  }
  
  /**
   * Initialize POSIX-UEFI and call the application's main() function
   */
  efi_status_t uefi_init (
  #ifndef __clang__
      uintptr_t ldbase, Elf64_Dyn *dyn, efi_system_table_t *systab, efi_handle_t image
  #else
      efi_handle_t image, efi_system_table_t *systab
  #endif
  ) {
      efi_guid_t shpGuid = EFI_SHELL_PARAMETERS_PROTOCOL_GUID;
      efi_shell_parameters_protocol_t *shp = NULL;
      efi_guid_t shiGuid = SHELL_INTERFACE_PROTOCOL_GUID;
      efi_shell_interface_protocol_t *shi = NULL;
      efi_guid_t lipGuid = EFI_LOADED_IMAGE_PROTOCOL_GUID;
      efi_status_t status;
      int argc = 0, i, ret;
      wchar_t **argv = NULL;
  #ifndef UEFI_NO_UTF8
      int j;
      char *s;
  #endif
  #ifndef __clang__
      long relsz = 0, relent = 0;
      Elf64_Rel *rel = 0;
      uintptr_t *addr;
      /* handle relocations */
      for (i = 0; dyn[i].d_tag != DT_NULL; ++i) {
          switch (dyn[i].d_tag) {
              case DT_RELA: rel = (Elf64_Rel*)((unsigned long)dyn[i].d_un.d_ptr + ldbase); break;
              case DT_RELASZ: relsz = dyn[i].d_un.d_val; break;
              case DT_RELAENT: relent = dyn[i].d_un.d_val; break;
              default: break;
          }
      }
      if (rel && relent) {
          while (relsz > 0) {
              if(ELF64_R_TYPE (rel->r_info) == R_X86_64_RELATIVE)
                  { addr = (unsigned long *)(ldbase + rel->r_offset); *addr += ldbase; }
              rel = (Elf64_Rel*) ((char *) rel + relent);
              relsz -= relent;
          }
      }
  #else
      (void)i;
  #endif
      /* make sure SSE is enabled, because some say there are buggy firmware in the wild not doing that */
      __asm__ __volatile__ (
      "	movq %cr0, %rax\n"
      "	andb $0xF1, %al\n"
      "	movq %rax, %cr0\n"
      "	movq %cr4, %rax\n"
      "	orw $3 << 9, %ax\n"
      "	mov %rax, %cr4\n"
      );
      /* failsafes, should never happen */
      if(!image || !systab || !systab->BootServices || !systab->BootServices->HandleProtocol ||
          !systab->BootServices->OpenProtocol || !systab->BootServices->AllocatePool || !systab->BootServices->FreePool)
              return EFI_UNSUPPORTED;
      /* save EFI pointers and loaded image into globals */
      IM = image;
      ST = systab;
      BS = systab->BootServices;
      RT = systab->RuntimeServices;
      BS->HandleProtocol(image, &lipGuid, (void **)&LIP);
      /* get command line arguments */
      status = BS->OpenProtocol(image, &shpGuid, (void **)&shp, image, NULL, EFI_OPEN_PROTOCOL_GET_PROTOCOL);
      if(!EFI_ERROR(status) && shp) { argc = shp->Argc; argv = shp->Argv; }
      else {
          /* if shell 2.0 failed, fallback to shell 1.0 interface */
          status = BS->OpenProtocol(image, &shiGuid, (void **)&shi, image, NULL, EFI_OPEN_PROTOCOL_GET_PROTOCOL);
          if(!EFI_ERROR(status) && shi) { argc = shi->Argc; argv = shi->Argv; }
      }
      /* call main */
  #ifndef UEFI_NO_UTF8
      if(argc && argv) {
          ret = (argc + 1) * (sizeof(uintptr_t) + 1);
          for(i = 0; i < argc; i++)
              for(j = 0; argv[i] && argv[i][j]; j++)
                  ret += argv[i][j] < 0x80 ? 1 : (argv[i][j] < 0x800 ? 2 : 3);
          status = BS->AllocatePool(LIP ? LIP->ImageDataType : EfiLoaderData, ret, (void **)&__argvutf8);
          if(EFI_ERROR(status) || !__argvutf8) { argc = 0; __argvutf8 = NULL; }
          else {
              s = __argvutf8 + argc * sizeof(uintptr_t);
              *((uintptr_t*)s) = (uintptr_t)0; s += sizeof(uintptr_t);
              for(i = 0; i < argc; i++) {
                  *((uintptr_t*)(__argvutf8 + i * sizeof(uintptr_t))) = (uintptr_t)s;
                  for(j = 0; argv[i] && argv[i][j]; j++) {
                      if(argv[i][j]<0x80) { *s++ = argv[i][j]; } else
                      if(argv[i][j]<0x800) { *s++ = ((argv[i][j]>>6)&0x1F)|0xC0; *s++ = (argv[i][j]&0x3F)|0x80; } else
                      { *s++ = ((argv[i][j]>>12)&0x0F)|0xE0; *s++ = ((argv[i][j]>>6)&0x3F)|0x80; *s++ = (argv[i][j]&0x3F)|0x80; }
                  }
                  *s++ = 0;
              }
          }
      }
      ret = main(argc, (char**)__argvutf8);
      if(__argvutf8) BS->FreePool(__argvutf8);
  #else
      ret = main(argc, argv);
  #endif
      return ret ? EFIERR(ret) : EFI_SUCCESS;
  }
  