Index: src/third_party/bootstub/files/bootstub.c |
diff --git a/src/third_party/bootstub/files/bootstub.c b/src/third_party/bootstub/files/bootstub.c |
new file mode 100644 |
index 0000000000000000000000000000000000000000..e98dd36cb161abc2960c26a9343202519e308a72 |
--- /dev/null |
+++ b/src/third_party/bootstub/files/bootstub.c |
@@ -0,0 +1,186 @@ |
+// Copyright (c) 2010 The Chromium OS Authors. All rights reserved. |
+// |
+// This program is free software: you can redistribute it and/or modify |
+// it under the terms of the GNU General Public License as published by |
+// the Free Software Foundation, either version 3 of the License, or |
+// (at your option) any later version. |
+// |
+// This program is distributed in the hope that it will be useful, |
+// but WITHOUT ANY WARRANTY; without even the implied warranty of |
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
+// GNU General Public License for more details. |
+// |
+// You should have received a copy of the GNU General Public License |
+// along with this program. If not, see <http://www.gnu.org/licenses/>. |
+ |
+#include <efi.h> |
+#include <efilib.h> |
+ |
+// Here's a struct to locate the pointers we need to update in the zeropage |
+// structure. Everything else should already be hardcoded at compile time. |
+// See arch/x86/include/asm/bootparam.h in the kernel source for the real deal. |
+struct hacked_params { |
+ uint8_t pad0[0x1c0]; |
+ uint32_t v0206_efi_signature; /* 1c0 */ |
+ uint32_t v0206_efi_system_table; /* 1c4 */ |
+ uint32_t v0206_efi_mem_desc_size; /* 1c8 */ |
+ uint32_t v0206_efi_mem_desc_version; /* 1cc */ |
+ uint32_t v0206_efi_mmap; /* 1d0 */ |
+ uint32_t v0206_efi_mmap_size; /* 1d4 */ |
+ uint32_t v0206_efi_system_table_hi; /* 1d8 */ |
+ uint32_t v0206_efi_mmap_hi; /* 1dc */ |
+ uint8_t pad1[0x214 - 0x1e0]; |
+ uint32_t code32_start; /* 214 */ |
+ uint8_t pad2[0x228 - 0x218]; |
+ uint32_t cmd_line_ptr; /* 228 */ |
+} __attribute__ ((packed)); |
+ |
+ |
+// Find where the preloaded params struct is located in RAM. At the moment |
+// we're assuming that it immediately precedes the start of the bootstub, |
+// aligned to a 4K boundary, because that's where our build system puts it. |
Randall Spangler
2010/05/21 18:37:26
Does this also need a FIXME / reference?
|
+struct hacked_params *find_params_struct(UINTN bootstub_location) |
+{ |
+ return (struct hacked_params *)(bootstub_location - 0x1000); |
+} |
+ |
+// Replace any %D with the device letter, and replace any %P with the partition |
+// number. For example, ("root=/dev/sd%D%P",2,3) gives "root=/dev/sdc3". The |
+// input string must be mutable and end with a trailing '\0'. |
+void update_cmdline_inplace(char *src, int devnum, int partnum) |
+{ |
+ char *dst; |
+ |
+ // Use sane values (sda3) for ridiculous inputs. |
+ if (devnum < 0 || devnum > 25 || partnum < 1 || partnum > 99) |
+ { |
+ devnum = 0; |
+ partnum = 3; |
+ } |
+ |
+ for( dst = src; *src; src++, dst++ ) |
+ { |
+ if ( src[0] == '%' ) |
+ { |
+ switch (src[1]) |
+ { |
+ case 'P': |
+ if (partnum > 9) |
+ *dst++ = '0' + (partnum / 10); |
+ *dst = '0' + partnum % 10; |
+ src++; |
+ break; |
+ case 'D': |
+ *dst = 'a' + devnum; |
+ src++; |
+ break; |
+ default: |
+ *dst = *src; |
+ } |
+ } |
+ else if (dst != src) |
+ *dst = *src; |
+ } |
+ *dst = '\0'; |
+} |
+ |
+// This is handy to write status codes to the LEDs for debugging. |
+static __inline void port80w (unsigned short int value) |
+{ |
+ __asm__ __volatile__ ("outw %w0,$0x80": :"a" (value)); |
+} |
+ |
+ |
+// The code to switch to 32-bit mode and start the kernel. |
+extern void trampoline(unsigned long, void *); |
+ |
+ |
+// Reserve some space for the EFI memory map. |
+// Danger Will Robinson: this is just a guess at the size and alignment. If |
+// it's too small, the EFI GetMemoryMap() call will fail. |
+// FIXME: Make the size dynamic? Retry with larger size on failure? |
+static unsigned char mmap_buf[0x2000] __attribute__ ((aligned(0x200))); |
+ |
+// Parameters that we're given by the BIOS |
+typedef struct cros_boot_info { |
+ UINTN drive_number; // 0 - 25 |
+ UINTN partition_number; // 1 - 99 |
+ UINTN original_address; // our RAM address prior to execution |
+} cros_boot_info_t; |
+ |
+ |
+// Here's the entry point. It will be loaded by the BIOS as a standard EFI |
+// application, which means it will be relocated. |
+EFI_STATUS efi_main (EFI_HANDLE image, EFI_SYSTEM_TABLE *systab) |
+{ |
+ UINTN mmap_size = sizeof(mmap_buf); |
+ UINTN mmap_key = 0; |
+ UINTN desc_size = 0; |
+ UINT32 desc_version = 0; |
+ EFI_LOADED_IMAGE *loaded_image; |
+ EFI_GUID loaded_image_protocol = LOADED_IMAGE_PROTOCOL; |
+ |
+ // I'm here. |
+ port80w(0xc0de); |
+ |
+ // Find the parameters that the BIOS has passed to us. |
+ if (uefi_call_wrapper(systab->BootServices->HandleProtocol, 3, |
+ image, |
+ &loaded_image_protocol, |
+ &loaded_image) != 0) |
+ { |
+ uefi_call_wrapper(systab->ConOut->OutputString, 3, systab->ConOut, |
+ L"Can't locate protocol\r\n"); |
+ goto fail; |
+ } |
+ cros_boot_info_t *booting = loaded_image->LoadOptions; |
+ |
+ // Find the parameters that we're passing to the kernel. |
+ struct hacked_params *params = find_params_struct(booting->original_address); |
+ |
+ // Update the kernel command-line string with the correct rootfs device |
+ update_cmdline_inplace((char *)(unsigned long)(params->cmd_line_ptr), |
+ booting->drive_number, |
+ booting->partition_number + 1); |
+ |
+ // Obtain the EFI memory map. |
+ if (uefi_call_wrapper(systab->BootServices->GetMemoryMap, 5, |
+ &mmap_size, mmap_buf, &mmap_key, |
+ &desc_size, &desc_version) != 0) |
+ { |
+ uefi_call_wrapper(systab->ConOut->OutputString, 2, systab->ConOut, |
+ L"Can't get memory map\r\n"); |
+ goto fail; |
+ } |
+ |
+ // Update the pointers to the EFI memory map and system table. |
+ params->v0206_efi_signature = ('4' << 24 | '6' << 16 | 'L' << 8 | 'E'); |
+ params->v0206_efi_system_table = (uint32_t) (unsigned long)systab; |
+ params->v0206_efi_mem_desc_size = desc_size; |
+ params->v0206_efi_mem_desc_version = desc_version; |
+ params->v0206_efi_mmap = (uint32_t) (unsigned long)mmap_buf; |
+ params->v0206_efi_mmap_size = mmap_size; |
+ params->v0206_efi_mmap_hi = (uint32_t)((uint64_t)mmap_buf >> 32); |
+ params->v0206_efi_system_table_hi = (uint32_t) ((uint64_t)systab >> 32); |
+ |
+ |
+ // Done with BIOS. |
+ if (uefi_call_wrapper(systab->BootServices->ExitBootServices, 2, |
+ image, mmap_key) != 0) |
+ { |
+ uefi_call_wrapper(systab->ConOut->OutputString, 2, systab->ConOut, |
+ L"Can't exit boot services\r\n"); |
+ goto fail; |
+ } |
+ |
+ |
+ // Trampoline to 32-bit entry point. Should never return. |
+ trampoline(params->code32_start, params); |
+ |
+fail: |
+ |
+ // Bad Things happened. |
+ port80w(0xdead); |
+ |
+ return EFI_LOAD_ERROR; |
+} |