Syncboot/gnu-efi/apps/debughook.c
Curle d588e232c4 Major overhaul of this branch.
This branch has been dedicated to purely the UEFI bootloader.
As such, all other code has been removed.

This code can be compiled with Visual Studio, gcc or llvm.
2019-07-17 21:10:29 +01:00

98 lines
2.0 KiB
C

#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}};
#if defined(__clang__)
# define _OPTNONE __attribute__((optnone))
#else
# define _OPTNONE __attribute__((__optimize__("0")))
#endif
static _OPTNONE void
DebugHook(void)
{
EFI_GUID guid = DUMMY_GUID;
UINT8 *data = NULL;
UINTN dataSize = 0;
EFI_STATUS efi_status;
register volatile unsigned long long 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 > 4294967294ULL)
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;
}