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