| #include <efi.h> |
| #include <efilib.h> |
| |
| EFI_STATUS |
| GetVariableAttr(CHAR16 *var, UINT8 **data, UINTN *len, EFI_GUID owner, |
| UINT32 *attributes) |
| { |
| EFI_STATUS efi_status; |
| |
| *len = 0; |
| |
| efi_status = uefi_call_wrapper(RT->GetVariable, 5, var, &owner, |
| NULL, len, NULL); |
| if (efi_status != EFI_BUFFER_TOO_SMALL) |
| return efi_status; |
| |
| *data = AllocateZeroPool(*len); |
| if (!*data) |
| return EFI_OUT_OF_RESOURCES; |
| |
| efi_status = uefi_call_wrapper(RT->GetVariable, 5, var, &owner, |
| attributes, len, *data); |
| |
| if (efi_status != EFI_SUCCESS) { |
| FreePool(*data); |
| *data = NULL; |
| } |
| return efi_status; |
| } |
| |
| EFI_STATUS |
| GetVariable(CHAR16 *var, UINT8 **data, UINTN *len, EFI_GUID owner) |
| { |
| return GetVariableAttr(var, data, len, owner, NULL); |
| } |
| |
| EFI_GUID DUMMY_GUID = |
| {0x55aad538, 0x8f82, 0x4e2a, {0xa4,0xf0,0xbe, 0x59, 0x13, 0xb6, 0x5f, 0x1e}}; |
| |
| static void |
| __attribute__((__optimize__("0"))) |
| DebugHook(void) |
| { |
| EFI_GUID guid = DUMMY_GUID; |
| UINT8 *data = NULL; |
| UINTN dataSize = 0; |
| EFI_STATUS efi_status; |
| register volatile UINTN x = 0; |
| extern char _text, _data; |
| |
| if (x) |
| return; |
| |
| efi_status = GetVariable(L"DUMMY_DEBUG", &data, &dataSize, guid); |
| if (EFI_ERROR(efi_status)) { |
| return; |
| } |
| |
| Print(L"add-symbol-file /usr/lib/debug/boot/efi/debughook.debug " |
| L"0x%08x -s .data 0x%08x\n", &_text, &_data); |
| |
| Print(L"Pausing for debugger attachment.\n"); |
| Print(L"To disable this, remove the EFI variable DUMMY_DEBUG-%g .\n", |
| &guid); |
| x = 1; |
| while (x++) { |
| /* Make this so it can't /totally/ DoS us. */ |
| #if defined(__x86_64__) || defined(__i386__) || defined(__i686__) |
| if (x > 4294967294) |
| break; |
| __asm__ __volatile__("pause"); |
| #elif defined(__aarch64__) |
| if (x > 1000) |
| break; |
| __asm__ __volatile__("wfi"); |
| #else |
| if (x > 12000) |
| break; |
| uefi_call_wrapper(BS->Stall, 1, 5000); |
| #endif |
| } |
| x = 1; |
| } |
| |
| |
| EFI_STATUS |
| efi_main (EFI_HANDLE image, EFI_SYSTEM_TABLE *systab) |
| { |
| InitializeLib(image, systab); |
| DebugHook(); |
| return EFI_SUCCESS; |
| } |
