[mirror_edk2.git] / MdePkg / Library / BaseLib / x86Thunk.c

/** @file\r
  Real Mode Thunk Functions for IA32 and X64.\r
\r
  Copyright (c) 2006, Intel Corporation<BR>\r
  All rights reserved. This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
  Module Name:  x86Thunk.c\r
\r
**/\r
\r
//\r
// Byte packed structure for a segment descriptor in a GDT/LDT\r
//\r
typedef union {\r
  struct {\r
    UINT32  LimitLow:16;\r
    UINT32  BaseLow:16;\r
    UINT32  BaseMid:8;\r
    UINT32  Type:4;\r
    UINT32  S:1;\r
    UINT32  DPL:2;\r
    UINT32  P:1;\r
    UINT32  LimitHigh:4;\r
    UINT32  AVL:1;\r
    UINT32  L:1;\r
    UINT32  DB:1;\r
    UINT32  G:1;\r
    UINT32  BaseHigh:8;\r
  } Bits;\r
  UINT64  Uint64;\r
} IA32_SEGMENT_DESCRIPTOR;\r
\r
extern CONST UINT8                  m16Start;\r
extern CONST UINT16                 m16Size;\r
extern CONST UINT16                 mThunk16Attr;\r
extern CONST UINT16                 m16Gdt;\r
extern CONST UINT16                 m16GdtrBase;\r
extern CONST UINT16                 mTransition;\r
\r
/**\r
  Invokes 16-bit code in big real mode and returns the updated register set.\r
\r
  This function transfers control to the 16-bit code specified by CS:EIP using\r
  the stack specified by SS:ESP in RegisterSet. The updated registers are saved\r
  on the real mode stack and the starting address of the save area is returned.\r
\r
  @param  RegisterSet Values of registers before invocation of 16-bit code.\r
  @param  Transition  Pointer to the transition code under 1MB.\r
\r
  @return The pointer to a IA32_REGISTER_SET structure containing the updated\r
          register values.\r
\r
**/\r
IA32_REGISTER_SET *\r
InternalAsmThunk16 (\r
  IN      IA32_REGISTER_SET         *RegisterSet,\r
  IN OUT  VOID                      *Transition\r
  );\r
\r
/**\r
  Retrieves the properties for 16-bit thunk functions.\r
\r
  Computes the size of the buffer and stack below 1MB required to use the\r
  AsmPrepareThunk16(), AsmThunk16() and AsmPrepareAndThunk16() functions. This\r
  buffer size is returned in RealModeBufferSize, and the stack size is returned\r
  in ExtraStackSize. If parameters are passed to the 16-bit real mode code,\r
  then the actual minimum stack size is ExtraStackSize plus the maximum number\r
  of bytes that need to be passed to the 16-bit real mode code.\r
\r
  If RealModeBufferSize is NULL, then ASSERT().\r
  If ExtraStackSize is NULL, then ASSERT().\r
\r
  @param  RealModeBufferSize  A pointer to the size of the buffer below 1MB\r
                              required to use the 16-bit thunk functions.\r
  @param  ExtraStackSize      A pointer to the extra size of stack below 1MB\r
                              that the 16-bit thunk functions require for\r
                              temporary storage in the transition to and from\r
                              16-bit real mode.\r
\r
**/\r
VOID\r
EFIAPI\r
AsmGetThunk16Properties (\r
  OUT     UINT32                    *RealModeBufferSize,\r
  OUT     UINT32                    *ExtraStackSize\r
  )\r
{\r
  ASSERT (RealModeBufferSize != NULL);\r
  ASSERT (ExtraStackSize != NULL);\r
\r
  *RealModeBufferSize = m16Size;\r
  *ExtraStackSize = sizeof (IA32_DWORD_REGS) + 8;\r
}\r
\r
/**\r
  Prepares all structures a code required to use AsmThunk16().\r
\r
  Prepares all structures and code required to use AsmThunk16().\r
\r
  If ThunkContext is NULL, then ASSERT().\r
\r
  @param  ThunkContext  A pointer to the context structure that describes the\r
                        16-bit real mode code to call.\r
\r
**/\r
VOID\r
EFIAPI\r
AsmPrepareThunk16 (\r
  OUT     THUNK_CONTEXT             *ThunkContext\r
  )\r
{\r
  IA32_SEGMENT_DESCRIPTOR           *RealModeGdt;\r
\r
  ASSERT (ThunkContext != NULL);\r
  ASSERT ((UINTN)ThunkContext->RealModeBuffer < 0x100000);\r
  ASSERT (ThunkContext->RealModeBufferSize >= m16Size);\r
  ASSERT ((UINTN)ThunkContext->RealModeBuffer + m16Size <= 0x100000);\r
\r
  CopyMem (ThunkContext->RealModeBuffer, &m16Start, m16Size);\r
\r
  //\r
  // Point RealModeGdt to the GDT to be used in transition\r
  //\r
  // RealModeGdt[0]: Reserved as NULL descriptor\r
  // RealModeGdt[1]: Code Segment\r
  // RealModeGdt[2]: Data Segment\r
  // RealModeGdt[3]: Call Gate\r
  //\r
  RealModeGdt = (IA32_SEGMENT_DESCRIPTOR*)(\r
                  (UINTN)ThunkContext->RealModeBuffer + m16Gdt);\r
\r
  //\r
  // Update Code & Data Segment Descriptor\r
  //\r
  RealModeGdt[1].Bits.BaseLow =\r
    (UINT32)(UINTN)ThunkContext->RealModeBuffer & ~0xf;\r
  RealModeGdt[1].Bits.BaseMid =\r
    (UINT32)(UINTN)ThunkContext->RealModeBuffer >> 16;\r
\r
  //\r
  // Update transition code entry point offset\r
  //\r
  *(UINT32*)((UINTN)ThunkContext->RealModeBuffer + mTransition) +=\r
    (UINT32)(UINTN)ThunkContext->RealModeBuffer & 0xf;\r
\r
  //\r
  // Update Segment Limits for both Code and Data Segment Descriptors\r
  //\r
  if ((ThunkContext->ThunkAttributes & THUNK_ATTRIBUTE_BIG_REAL_MODE) == 0) {\r
    //\r
    // Set segment limits to 64KB\r
    //\r
    RealModeGdt[1].Bits.LimitHigh = 0;\r
    RealModeGdt[1].Bits.G = 0;\r
    RealModeGdt[2].Bits.LimitHigh = 0;\r
    RealModeGdt[2].Bits.G = 0;\r
  }\r
\r
  //\r
  // Update GDTBASE for this thunk context\r
  //\r
  *(VOID**)((UINTN)ThunkContext->RealModeBuffer + m16GdtrBase) = RealModeGdt;\r
\r
  //\r
  // Update Thunk Attributes\r
  //\r
  *(UINT32*)((UINTN)ThunkContext->RealModeBuffer + mThunk16Attr) =\r
    ThunkContext->ThunkAttributes;\r
}\r
\r
/**\r
  Transfers control to a 16-bit real mode entry point and returns the results.\r
\r
  Transfers control to a 16-bit real mode entry point and returns the results.\r
  AsmPrepareThunk16() must be called with ThunkContext before this function is\r
  used. This function must be called with interrupts disabled.\r
\r
  If ThunkContext is NULL, then ASSERT().\r
  If AsmPrepareThunk16() was not previously called with ThunkContext, then ASSERT().\r
\r
  @param  ThunkContext  A pointer to the context structure that describes the\r
                        16-bit real mode code to call.\r
\r
**/\r
VOID\r
EFIAPI\r
AsmThunk16 (\r
  IN OUT  THUNK_CONTEXT             *ThunkContext\r
  )\r
{\r
  IA32_REGISTER_SET                 *UpdatedRegs;\r
\r
  ASSERT (ThunkContext != NULL);\r
  ASSERT ((UINTN)ThunkContext->RealModeBuffer < 0x100000);\r
  ASSERT (ThunkContext->RealModeBufferSize >= m16Size);\r
  ASSERT ((UINTN)ThunkContext->RealModeBuffer + m16Size <= 0x100000);\r
\r
  UpdatedRegs = InternalAsmThunk16 (\r
                  ThunkContext->RealModeState,\r
                  ThunkContext->RealModeBuffer\r
                  );\r
\r
  CopyMem (ThunkContext->RealModeState, UpdatedRegs, sizeof (*UpdatedRegs));\r
}\r
\r
/**\r
  Prepares all structures and code for a 16-bit real mode thunk, transfers\r
  control to a 16-bit real mode entry point, and returns the results.\r
\r
  Prepares all structures and code for a 16-bit real mode thunk, transfers\r
  control to a 16-bit real mode entry point, and returns the results. If the\r
  caller only need to perform a single 16-bit real mode thunk, then this\r
  service should be used. If the caller intends to make more than one 16-bit\r
  real mode thunk, then it is more efficient if AsmPrepareThunk16() is called\r
  once and AsmThunk16() can be called for each 16-bit real mode thunk. This\r
  function must be called with interrupts disabled.\r
\r
  If ThunkContext is NULL, then ASSERT().\r
\r
  @param  ThunkContext  A pointer to the context structure that describes the\r
                        16-bit real mode code to call.\r
\r
**/\r
VOID\r
EFIAPI\r
AsmPrepareAndThunk16 (\r
  IN OUT  THUNK_CONTEXT             *ThunkContext\r
  )\r
{\r
  AsmPrepareThunk16 (ThunkContext);\r
  AsmThunk16 (ThunkContext);\r
}\r
Commit	Line	Data
	1	/** @file\r
	2	Real Mode Thunk Functions for IA32 and X64.\r
	3	\r
	4	Copyright (c) 2006, Intel Corporation<BR>\r
	5	All rights reserved. This program and the accompanying materials\r
	6	are licensed and made available under the terms and conditions of the BSD License\r
	7	which accompanies this distribution. The full text of the license may be found at\r
	8	http://opensource.org/licenses/bsd-license.php\r
	9	\r
	10	THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
	11	WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
	12	\r
	13	Module Name: x86Thunk.c\r
	14	\r
	15	**/\r
	16	\r
	17	//\r
	18	// Byte packed structure for a segment descriptor in a GDT/LDT\r
	19	//\r
	20	typedef union {\r
	21	struct {\r
	22	UINT32 LimitLow:16;\r
	23	UINT32 BaseLow:16;\r
	24	UINT32 BaseMid:8;\r
	25	UINT32 Type:4;\r
	26	UINT32 S:1;\r
	27	UINT32 DPL:2;\r
	28	UINT32 P:1;\r
	29	UINT32 LimitHigh:4;\r
	30	UINT32 AVL:1;\r
	31	UINT32 L:1;\r
	32	UINT32 DB:1;\r
	33	UINT32 G:1;\r
	34	UINT32 BaseHigh:8;\r
	35	} Bits;\r
	36	UINT64 Uint64;\r
	37	} IA32_SEGMENT_DESCRIPTOR;\r
	38	\r
	39	extern CONST UINT8 m16Start;\r
	40	extern CONST UINT16 m16Size;\r
	41	extern CONST UINT16 mThunk16Attr;\r
	42	extern CONST UINT16 m16Gdt;\r
	43	extern CONST UINT16 m16GdtrBase;\r
	44	extern CONST UINT16 mTransition;\r
	45	\r
	46	/**\r
	47	Invokes 16-bit code in big real mode and returns the updated register set.\r
	48	\r
	49	This function transfers control to the 16-bit code specified by CS:EIP using\r
	50	the stack specified by SS:ESP in RegisterSet. The updated registers are saved\r
	51	on the real mode stack and the starting address of the save area is returned.\r
	52	\r
	53	@param RegisterSet Values of registers before invocation of 16-bit code.\r
	54	@param Transition Pointer to the transition code under 1MB.\r
	55	\r
	56	@return The pointer to a IA32_REGISTER_SET structure containing the updated\r
	57	register values.\r
	58	\r
	59	**/\r
	60	IA32_REGISTER_SET *\r
	61	InternalAsmThunk16 (\r
	62	IN IA32_REGISTER_SET *RegisterSet,\r
	63	IN OUT VOID *Transition\r
	64	);\r
	65	\r
	66	/**\r
	67	Retrieves the properties for 16-bit thunk functions.\r
	68	\r
	69	Computes the size of the buffer and stack below 1MB required to use the\r
	70	AsmPrepareThunk16(), AsmThunk16() and AsmPrepareAndThunk16() functions. This\r
	71	buffer size is returned in RealModeBufferSize, and the stack size is returned\r
	72	in ExtraStackSize. If parameters are passed to the 16-bit real mode code,\r
	73	then the actual minimum stack size is ExtraStackSize plus the maximum number\r
	74	of bytes that need to be passed to the 16-bit real mode code.\r
	75	\r
	76	If RealModeBufferSize is NULL, then ASSERT().\r
	77	If ExtraStackSize is NULL, then ASSERT().\r
	78	\r
	79	@param RealModeBufferSize A pointer to the size of the buffer below 1MB\r
	80	required to use the 16-bit thunk functions.\r
	81	@param ExtraStackSize A pointer to the extra size of stack below 1MB\r
	82	that the 16-bit thunk functions require for\r
	83	temporary storage in the transition to and from\r
	84	16-bit real mode.\r
	85	\r
	86	**/\r
	87	VOID\r
	88	EFIAPI\r
	89	AsmGetThunk16Properties (\r
	90	OUT UINT32 *RealModeBufferSize,\r
	91	OUT UINT32 *ExtraStackSize\r
	92	)\r
	93	{\r
	94	ASSERT (RealModeBufferSize != NULL);\r
	95	ASSERT (ExtraStackSize != NULL);\r
	96	\r
	97	*RealModeBufferSize = m16Size;\r
	98	*ExtraStackSize = sizeof (IA32_DWORD_REGS) + 8;\r
	99	}\r
	100	\r
	101	/**\r
	102	Prepares all structures a code required to use AsmThunk16().\r
	103	\r
	104	Prepares all structures and code required to use AsmThunk16().\r
	105	\r
	106	If ThunkContext is NULL, then ASSERT().\r
	107	\r
	108	@param ThunkContext A pointer to the context structure that describes the\r
	109	16-bit real mode code to call.\r
	110	\r
	111	**/\r
	112	VOID\r
	113	EFIAPI\r
	114	AsmPrepareThunk16 (\r
	115	OUT THUNK_CONTEXT *ThunkContext\r
	116	)\r
	117	{\r
	118	IA32_SEGMENT_DESCRIPTOR *RealModeGdt;\r
	119	\r
	120	ASSERT (ThunkContext != NULL);\r
	121	ASSERT ((UINTN)ThunkContext->RealModeBuffer < 0x100000);\r
	122	ASSERT (ThunkContext->RealModeBufferSize >= m16Size);\r
	123	ASSERT ((UINTN)ThunkContext->RealModeBuffer + m16Size <= 0x100000);\r
	124	\r
	125	CopyMem (ThunkContext->RealModeBuffer, &m16Start, m16Size);\r
	126	\r
	127	//\r
	128	// Point RealModeGdt to the GDT to be used in transition\r
	129	//\r
	130	// RealModeGdt[0]: Reserved as NULL descriptor\r
	131	// RealModeGdt[1]: Code Segment\r
	132	// RealModeGdt[2]: Data Segment\r
	133	// RealModeGdt[3]: Call Gate\r
	134	//\r
	135	RealModeGdt = (IA32_SEGMENT_DESCRIPTOR*)(\r
	136	(UINTN)ThunkContext->RealModeBuffer + m16Gdt);\r
	137	\r
	138	//\r
	139	// Update Code & Data Segment Descriptor\r
	140	//\r
	141	RealModeGdt[1].Bits.BaseLow =\r
	142	(UINT32)(UINTN)ThunkContext->RealModeBuffer & ~0xf;\r
	143	RealModeGdt[1].Bits.BaseMid =\r
	144	(UINT32)(UINTN)ThunkContext->RealModeBuffer >> 16;\r
	145	\r
	146	//\r
	147	// Update transition code entry point offset\r
	148	//\r
	149	(UINT32)((UINTN)ThunkContext->RealModeBuffer + mTransition) +=\r
	150	(UINT32)(UINTN)ThunkContext->RealModeBuffer & 0xf;\r
	151	\r
	152	//\r
	153	// Update Segment Limits for both Code and Data Segment Descriptors\r
	154	//\r
	155	if ((ThunkContext->ThunkAttributes & THUNK_ATTRIBUTE_BIG_REAL_MODE) == 0) {\r
	156	//\r
	157	// Set segment limits to 64KB\r
	158	//\r
	159	RealModeGdt[1].Bits.LimitHigh = 0;\r
	160	RealModeGdt[1].Bits.G = 0;\r
	161	RealModeGdt[2].Bits.LimitHigh = 0;\r
	162	RealModeGdt[2].Bits.G = 0;\r
	163	}\r
	164	\r
	165	//\r
	166	// Update GDTBASE for this thunk context\r
	167	//\r
	168	(VOID*)((UINTN)ThunkContext->RealModeBuffer + m16GdtrBase) = RealModeGdt;\r
	169	\r
	170	//\r
	171	// Update Thunk Attributes\r
	172	//\r
	173	(UINT32)((UINTN)ThunkContext->RealModeBuffer + mThunk16Attr) =\r
	174	ThunkContext->ThunkAttributes;\r
	175	}\r
	176	\r
	177	/**\r
	178	Transfers control to a 16-bit real mode entry point and returns the results.\r
	179	\r
	180	Transfers control to a 16-bit real mode entry point and returns the results.\r
	181	AsmPrepareThunk16() must be called with ThunkContext before this function is\r
	182	used. This function must be called with interrupts disabled.\r
	183	\r
	184	If ThunkContext is NULL, then ASSERT().\r
	185	If AsmPrepareThunk16() was not previously called with ThunkContext, then ASSERT().\r
	186	\r
	187	@param ThunkContext A pointer to the context structure that describes the\r
	188	16-bit real mode code to call.\r
	189	\r
	190	**/\r
	191	VOID\r
	192	EFIAPI\r
	193	AsmThunk16 (\r
	194	IN OUT THUNK_CONTEXT *ThunkContext\r
	195	)\r
	196	{\r
	197	IA32_REGISTER_SET *UpdatedRegs;\r
	198	\r
	199	ASSERT (ThunkContext != NULL);\r
	200	ASSERT ((UINTN)ThunkContext->RealModeBuffer < 0x100000);\r
	201	ASSERT (ThunkContext->RealModeBufferSize >= m16Size);\r
	202	ASSERT ((UINTN)ThunkContext->RealModeBuffer + m16Size <= 0x100000);\r
	203	\r
	204	UpdatedRegs = InternalAsmThunk16 (\r
	205	ThunkContext->RealModeState,\r
	206	ThunkContext->RealModeBuffer\r
	207	);\r
	208	\r
	209	CopyMem (ThunkContext->RealModeState, UpdatedRegs, sizeof (*UpdatedRegs));\r
	210	}\r
	211	\r
	212	/**\r
	213	Prepares all structures and code for a 16-bit real mode thunk, transfers\r
	214	control to a 16-bit real mode entry point, and returns the results.\r
	215	\r
	216	Prepares all structures and code for a 16-bit real mode thunk, transfers\r
	217	control to a 16-bit real mode entry point, and returns the results. If the\r
	218	caller only need to perform a single 16-bit real mode thunk, then this\r
	219	service should be used. If the caller intends to make more than one 16-bit\r
	220	real mode thunk, then it is more efficient if AsmPrepareThunk16() is called\r
	221	once and AsmThunk16() can be called for each 16-bit real mode thunk. This\r
	222	function must be called with interrupts disabled.\r
	223	\r
	224	If ThunkContext is NULL, then ASSERT().\r
	225	\r
	226	@param ThunkContext A pointer to the context structure that describes the\r
	227	16-bit real mode code to call.\r
	228	\r
	229	**/\r
	230	VOID\r
	231	EFIAPI\r
	232	AsmPrepareAndThunk16 (\r
	233	IN OUT THUNK_CONTEXT *ThunkContext\r
	234	)\r
	235	{\r
	236	AsmPrepareThunk16 (ThunkContext);\r
	237	AsmThunk16 (ThunkContext);\r
	238	}\r