zircon/bootloader/src/zircon.c

// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <cmdline.h>
#include <inttypes.h>
#include <stdio.h>
#include <string.h>
#include <xefi.h>
#include <zircon/boot/image.h>
#include <zircon/pixelformat.h>

#include <efi/protocol/graphics-output.h>
#include <efi/runtime-services.h>

#include "osboot.h"

static efi_guid zircon_guid = ZIRCON_VENDOR_GUID;
static char16_t crashlog_name[] = ZIRCON_CRASHLOG_EFIVAR;

static size_t get_last_crashlog(efi_system_table* sys, void* ptr, size_t max) {
  efi_runtime_services* rs = sys->RuntimeServices;

  uint32_t attr = ZIRCON_CRASHLOG_EFIATTR;
  size_t sz = max;
  efi_status r = rs->GetVariable(crashlog_name, &zircon_guid, &attr, &sz, ptr);
  if (r == EFI_SUCCESS) {
    // Erase it
    rs->SetVariable(crashlog_name, &zircon_guid, ZIRCON_CRASHLOG_EFIATTR, 0, NULL);
  } else {
    sz = 0;
  }
  return sz;
}

static unsigned char scratch[32768];

static void start_zircon(uint64_t entry, void* bootdata) {
#if __x86_64__
  // ebx = 0, ebp = 0, edi = 0, esi = bootdata
  __asm__ __volatile__(
      "movl $0, %%ebp \n"
      "cli \n"
      "jmp *%[entry] \n" ::[entry] "a"(entry),
      [ bootdata ] "S"(bootdata), "b"(0), "D"(0));
#elif defined(__aarch64__)
  __asm__(
      "mov x0, %[zbi]\n"  // Argument register.
      "mov x29, xzr\n"    // Clear FP.
      "mov x30, xzr\n"    // Clear LR.
      "br %[entry]\n" ::[entry] "r"(entry),
      [ zbi ] "r"(bootdata)
      : "x0", "x29", "x30");
#else
#error "add code for other arches here"
#endif
  __builtin_unreachable();
}

static int add_bootdata(void** ptr, size_t* avail, zbi_header_t* bd, void* data) {
  size_t len = ZBI_ALIGN(bd->length);
  if ((sizeof(zbi_header_t) + len) > *avail) {
    printf("boot: no room for bootdata type=%08x size=%08x\n", bd->type, bd->length);
    return -1;
  }
  bd->flags |= ZBI_FLAG_VERSION;
  bd->reserved0 = 0;
  bd->reserved1 = 0;
  bd->magic = ZBI_ITEM_MAGIC;
  bd->crc32 = ZBI_ITEM_NO_CRC32;

  memcpy(*ptr, bd, sizeof(zbi_header_t));
  memcpy((*ptr) + sizeof(zbi_header_t), data, len);
  len += sizeof(zbi_header_t);
  (*ptr) += len;
  (*avail) -= len;

  return 0;
}

size_t image_getsize(void* image, size_t sz) {
  if (sz < sizeof(zircon_kernel_t)) {
    return 0;
  }
  zircon_kernel_t* kernel = image;
  if ((kernel->hdr_file.type != ZBI_TYPE_CONTAINER) || (kernel->hdr_file.magic != ZBI_ITEM_MAGIC) ||
      (kernel->hdr_kernel.type != ZBI_TYPE_KERNEL_X64) ||
      (kernel->hdr_kernel.magic != ZBI_ITEM_MAGIC)) {
    return 0;
  }
  return ZBI_ALIGN(kernel->hdr_file.length) + sizeof(zbi_header_t);
}

static int header_check(void* image, size_t sz, uint64_t* _entry, size_t* _flen, size_t* _klen) {
  zbi_header_t* bd = image;
  size_t flen, klen;
  uint64_t entry;

  if (!(bd->flags & ZBI_FLAG_VERSION)) {
    printf("boot: v1 bootdata kernel no longer supported\n");
    return -1;
  }
  zircon_kernel_t* kernel = image;
  if ((sz < sizeof(zircon_kernel_t)) || (kernel->hdr_kernel.type != ZBI_TYPE_KERNEL_X64) ||
      ((kernel->hdr_kernel.flags & ZBI_FLAG_VERSION) == 0)) {
    printf("boot: invalid zircon kernel header\n");
    return -1;
  }
  flen = ZBI_ALIGN(kernel->hdr_file.length);
  klen = ZBI_ALIGN(kernel->hdr_kernel.length);
  entry = kernel->data_kernel.entry;
  if (flen > (sz - sizeof(zbi_header_t))) {
    printf("boot: invalid zircon kernel header (bad flen)\n");
    return -1;
  }

  if (klen > (sz - (sizeof(zbi_header_t) * 2))) {
    printf("boot: invalid zircon kernel header (bad klen)\n");
    return -1;
  }
  if (_entry) {
    *_entry = entry;
  }
  if (_flen) {
    *_flen = flen;
    *_klen = klen;
  }

  return 0;
}

static int item_check(zbi_header_t* bd, size_t sz) {
  if (sz > 0x7FFFFFFF) {
    // disallow 2GB+ items to avoid wrap on align issues
    return -1;
  }
  if ((bd->magic != ZBI_ITEM_MAGIC) || ((bd->flags & ZBI_FLAG_VERSION) == 0) ||
      (ZBI_ALIGN(bd->length) > sz)) {
    return -1;
  } else {
    return 0;
  }
}

// TODO: verify crc32 when present
unsigned identify_image(void* image, size_t sz) {
  if (sz == 0) {
    return IMAGE_EMPTY;
  }
  if (sz < sizeof(zbi_header_t)) {
    printf("image is too small\n");
    return IMAGE_INVALID;
  }
  zbi_header_t* bd = image;
  sz -= sizeof(zbi_header_t);
  if ((bd->type != ZBI_TYPE_CONTAINER) || item_check(bd, sz)) {
    printf("image has invalid header\n");
    return IMAGE_INVALID;
  }
  image += sizeof(zbi_header_t);
  unsigned n = 0;
  unsigned r = 0;
  while (sz > sizeof(zbi_header_t)) {
    bd = image;
    sz -= sizeof(zbi_header_t);
    if (item_check(image, sz)) {
      printf("image has invalid bootitem\n");
      return IMAGE_INVALID;
    }
    if (ZBI_IS_KERNEL_BOOTITEM(bd->type)) {
      if (n != 0) {
        printf("image has kernel in middle\n");
        return IMAGE_INVALID;
      } else {
        r = IMAGE_KERNEL;
      }
    }
    if (bd->type == ZBI_TYPE_STORAGE_BOOTFS) {
      if ((r == IMAGE_KERNEL) || (r == IMAGE_COMBO)) {
        r = IMAGE_COMBO;
      } else {
        r = IMAGE_RAMDISK;
      }
    }
    image += ZBI_ALIGN(bd->length) + sizeof(zbi_header_t);
    sz -= ZBI_ALIGN(bd->length);
    n++;
  }

  return r;
}

int boot_zircon(efi_handle img, efi_system_table* sys, void* image, size_t isz, void* ramdisk,
                size_t rsz, void* cmdline, size_t csz) {
  efi_boot_services* bs = sys->BootServices;
  uint64_t entry;

  if (header_check(image, isz, &entry, NULL, NULL)) {
    return -1;
  }
  if ((ramdisk == NULL) || (rsz < sizeof(zbi_header_t))) {
    printf("boot: ramdisk missing or too small\n");
    return -1;
  }
  if (isz > kernel_zone_size) {
    printf("boot: kernel image too large\n");
    return -1;
  }

  zbi_header_t* hdr0 = ramdisk;
  if ((hdr0->type != ZBI_TYPE_CONTAINER) || (hdr0->extra != ZBI_CONTAINER_MAGIC) ||
      !(hdr0->flags & ZBI_FLAG_VERSION)) {
    printf("boot: ramdisk has invalid bootdata header\n");
    return -1;
  }

  if ((hdr0->length > (rsz - sizeof(zbi_header_t)))) {
    printf("boot: ramdisk has invalid bootdata length\n");
    return -1;
  }

  // osboot ensures we have FRONT_BYTES ahead of the
  // ramdisk to prepend our own bootdata items.
  void* bptr = ramdisk - FRONT_BYTES;
  size_t blen = FRONT_BYTES;

  // We create a new container header of the same size
  // as the one at the start of the ramdisk
  zbi_header_t hdr = ZBI_CONTAINER_HEADER(hdr0->length + FRONT_BYTES);
  memcpy(bptr, &hdr, sizeof(hdr));
  bptr += sizeof(hdr);

  // pass kernel commandline
  hdr.type = ZBI_TYPE_CMDLINE;
  hdr.length = csz;
  hdr.extra = 0;
  hdr.flags = ZBI_FLAG_VERSION;
  if (add_bootdata(&bptr, &blen, &hdr, cmdline)) {
    return -1;
  }

  // pass ACPI root pointer
  uint64_t rsdp = find_acpi_root(img, sys);
  if (rsdp != 0) {
    hdr.type = ZBI_TYPE_ACPI_RSDP;
    hdr.length = sizeof(rsdp);
    if (add_bootdata(&bptr, &blen, &hdr, &rsdp)) {
      return -1;
    }
  }

  // pass SMBIOS entry point pointer
  uint64_t smbios = find_smbios(img, sys);
  if (smbios != 0) {
    hdr.type = ZBI_TYPE_SMBIOS;
    hdr.length = sizeof(smbios);
    if (add_bootdata(&bptr, &blen, &hdr, &smbios)) {
      return -1;
    }
  }

  // pass EFI system table
  uint64_t addr = (uintptr_t)sys;
  hdr.type = ZBI_TYPE_EFI_SYSTEM_TABLE;
  hdr.length = sizeof(sys);
  if (add_bootdata(&bptr, &blen, &hdr, &addr)) {
    return -1;
  }

  // pass framebuffer data
  efi_graphics_output_protocol* gop = NULL;
  bs->LocateProtocol(&GraphicsOutputProtocol, NULL, (void**)&gop);
  if (gop) {
    zbi_swfb_t fb = {
        .base = gop->Mode->FrameBufferBase,
        .width = gop->Mode->Info->HorizontalResolution,
        .height = gop->Mode->Info->VerticalResolution,
        .stride = gop->Mode->Info->PixelsPerScanLine,
        .format = get_zx_pixel_format(gop),
    };
    hdr.type = ZBI_TYPE_FRAMEBUFFER;
    hdr.length = sizeof(fb);
    if (add_bootdata(&bptr, &blen, &hdr, &fb)) {
      return -1;
    }
  }

  memcpy((void*)kernel_zone_base, image, isz);

  // Obtain the system memory map
  size_t msize, dsize;
  for (int attempts = 0;; attempts++) {
    efi_memory_descriptor* mmap = (efi_memory_descriptor*)(scratch + sizeof(uint64_t));
    uint32_t dversion = 0;
    size_t mkey = 0;
    msize = sizeof(scratch) - sizeof(uint64_t);
    dsize = 0;
    efi_status r = sys->BootServices->GetMemoryMap(&msize, mmap, &mkey, &dsize, &dversion);
    if (r != EFI_SUCCESS) {
      printf("boot: cannot GetMemoryMap()\n");
      goto fail;
    }

    r = sys->BootServices->ExitBootServices(img, mkey);
    if (r == EFI_SUCCESS) {
      break;
    }
    if (r == EFI_INVALID_PARAMETER) {
      if (attempts > 0) {
        printf("boot: cannot ExitBootServices(): %s\n", xefi_strerror(r));
        goto fail;
      }
      // Attempting to exit may cause us to have to re-grab the
      // memory map, but if it happens more than once something's
      // broken.
      continue;
    }
    printf("boot: cannot ExitBootServices(): %s\n", xefi_strerror(r));
    goto fail;
  }
  memcpy(scratch, &dsize, sizeof(uint64_t));

  // install memory map
  hdr.type = ZBI_TYPE_EFI_MEMORY_MAP;
  hdr.length = msize + sizeof(uint64_t);
  if (add_bootdata(&bptr, &blen, &hdr, scratch)) {
    goto fail;
  }

  // obtain the last crashlog if we can
  size_t sz = get_last_crashlog(sys, scratch, 4096);
  if (sz > 0) {
    hdr.type = ZBI_TYPE_CRASHLOG;
    hdr.length = sz;
    add_bootdata(&bptr, &blen, &hdr, scratch);
  }

  // fill the remaining gap between pre-data and ramdisk image
  if ((blen < sizeof(hdr)) || (blen & 7)) {
    goto fail;
  }
  hdr.type = ZBI_TYPE_DISCARD;
  hdr.length = blen - sizeof(hdr);
  hdr.flags = ZBI_FLAG_VERSION;
  memcpy(bptr, &hdr, sizeof(hdr));

  // jump to the kernel
  start_zircon(entry, ramdisk - FRONT_BYTES);

fail:
  return -1;
}

static char cmdline[CMDLINE_MAX];

int zedboot(efi_handle img, efi_system_table* sys, void* image, size_t sz) {
  size_t flen, klen;
  if (header_check(image, sz, NULL, &flen, &klen)) {
    return -1;
  }

  // ramdisk portion is file - headers - kernel len
  uint32_t rlen = flen - sizeof(zbi_header_t) - klen;
  uint32_t roff = (sizeof(zbi_header_t) * 2) + klen;
  if (rlen == 0) {
    printf("zedboot: no ramdisk?!\n");
    return -1;
  }

  // allocate space for the ramdisk
  efi_boot_services* bs = sys->BootServices;
  size_t rsz = rlen + sizeof(zbi_header_t) + FRONT_BYTES;
  size_t pages = BYTES_TO_PAGES(rsz);
  void* ramdisk = NULL;
  efi_status r =
      bs->AllocatePages(AllocateAnyPages, EfiLoaderData, pages, (efi_physical_addr*)&ramdisk);
  if (r) {
    printf("zedboot: cannot allocate ramdisk buffer\n");
    return -1;
  }

  ramdisk += FRONT_BYTES;
  *(zbi_header_t*)ramdisk = (zbi_header_t)ZBI_CONTAINER_HEADER(rlen);
  memcpy(ramdisk + sizeof(zbi_header_t), image + roff, rlen);
  rlen += sizeof(zbi_header_t);

  printf("ramdisk @ %p\n", ramdisk);

  size_t csz = cmdline_to_string(cmdline, sizeof(cmdline));

  // shrink original image header to include only the kernel
  zircon_kernel_t* kernel = image;
  kernel->hdr_file.length = sizeof(zbi_header_t) + klen;

  return boot_zircon(img, sys, image, roff, ramdisk, rlen, cmdline, csz);
}

int boot_kernel(efi_handle img, efi_system_table* sys, void* image, size_t sz, void* ramdisk,
                size_t rsz) {
  size_t csz = cmdline_to_string(cmdline, sizeof(cmdline));

  zbi_header_t* bd = image;
  if ((bd->type == ZBI_TYPE_CONTAINER) && (bd->extra == ZBI_CONTAINER_MAGIC)) {
    return boot_zircon(img, sys, image, sz, ramdisk, rsz, cmdline, csz);
  } else {
    return -1;
  }
}