[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
EFIAPI\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
\r
  //\r
  // Extra 4 bytes for return address, and another 4 bytes for mode transition\r
  //\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
878ddf1f	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
97d92bda	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
878ddf1f	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
97d92bda	54	@param Transition Pointer to the transition code under 1MB.\r
878ddf1f	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
3f566587	61	EFIAPI\r
878ddf1f	62	InternalAsmThunk16 (\r
878ddf1f	63	IN IA32_REGISTER_SET *RegisterSet,\r
97d92bda	64	IN OUT VOID *Transition\r
878ddf1f	65	);\r
878ddf1f	66	\r
97d92bda	67	/**\r
	68	Retrieves the properties for 16-bit thunk functions.\r
	69	\r
	70	Computes the size of the buffer and stack below 1MB required to use the\r
	71	AsmPrepareThunk16(), AsmThunk16() and AsmPrepareAndThunk16() functions. This\r
	72	buffer size is returned in RealModeBufferSize, and the stack size is returned\r
	73	in ExtraStackSize. If parameters are passed to the 16-bit real mode code,\r
	74	then the actual minimum stack size is ExtraStackSize plus the maximum number\r
	75	of bytes that need to be passed to the 16-bit real mode code.\r
	76	\r
	77	If RealModeBufferSize is NULL, then ASSERT().\r
	78	If ExtraStackSize is NULL, then ASSERT().\r
	79	\r
	80	@param RealModeBufferSize A pointer to the size of the buffer below 1MB\r
	81	required to use the 16-bit thunk functions.\r
	82	@param ExtraStackSize A pointer to the extra size of stack below 1MB\r
	83	that the 16-bit thunk functions require for\r
	84	temporary storage in the transition to and from\r
	85	16-bit real mode.\r
	86	\r
	87	**/\r
	88	VOID\r
	89	EFIAPI\r
	90	AsmGetThunk16Properties (\r
	91	OUT UINT32 *RealModeBufferSize,\r
	92	OUT UINT32 *ExtraStackSize\r
	93	)\r
	94	{\r
	95	ASSERT (RealModeBufferSize != NULL);\r
	96	ASSERT (ExtraStackSize != NULL);\r
	97	\r
	98	*RealModeBufferSize = m16Size;\r
18c319ae	99	\r
	100	//\r
	101	// Extra 4 bytes for return address, and another 4 bytes for mode transition\r
	102	//\r
97d92bda	103	*ExtraStackSize = sizeof (IA32_DWORD_REGS) + 8;\r
	104	}\r
	105	\r
878ddf1f	106	/**\r
	107	Prepares all structures a code required to use AsmThunk16().\r
	108	\r
	109	Prepares all structures and code required to use AsmThunk16().\r
	110	\r
	111	If ThunkContext is NULL, then ASSERT().\r
	112	\r
	113	@param ThunkContext A pointer to the context structure that describes the\r
	114	16-bit real mode code to call.\r
	115	\r
	116	**/\r
	117	VOID\r
	118	EFIAPI\r
	119	AsmPrepareThunk16 (\r
	120	OUT THUNK_CONTEXT *ThunkContext\r
	121	)\r
	122	{\r
97d92bda	123	IA32_SEGMENT_DESCRIPTOR *RealModeGdt;\r
97d92bda	124	\r
878ddf1f	125	ASSERT (ThunkContext != NULL);\r
97d92bda	126	ASSERT ((UINTN)ThunkContext->RealModeBuffer < 0x100000);\r
	127	ASSERT (ThunkContext->RealModeBufferSize >= m16Size);\r
	128	ASSERT ((UINTN)ThunkContext->RealModeBuffer + m16Size <= 0x100000);\r
97d92bda	129	\r
	130	CopyMem (ThunkContext->RealModeBuffer, &m16Start, m16Size);\r
	131	\r
	132	//\r
	133	// Point RealModeGdt to the GDT to be used in transition\r
	134	//\r
	135	// RealModeGdt[0]: Reserved as NULL descriptor\r
	136	// RealModeGdt[1]: Code Segment\r
	137	// RealModeGdt[2]: Data Segment\r
	138	// RealModeGdt[3]: Call Gate\r
	139	//\r
	140	RealModeGdt = (IA32_SEGMENT_DESCRIPTOR*)(\r
	141	(UINTN)ThunkContext->RealModeBuffer + m16Gdt);\r
	142	\r
	143	//\r
	144	// Update Code & Data Segment Descriptor\r
	145	//\r
	146	RealModeGdt[1].Bits.BaseLow =\r
	147	(UINT32)(UINTN)ThunkContext->RealModeBuffer & ~0xf;\r
	148	RealModeGdt[1].Bits.BaseMid =\r
	149	(UINT32)(UINTN)ThunkContext->RealModeBuffer >> 16;\r
	150	\r
	151	//\r
	152	// Update transition code entry point offset\r
	153	//\r
	154	(UINT32)((UINTN)ThunkContext->RealModeBuffer + mTransition) +=\r
	155	(UINT32)(UINTN)ThunkContext->RealModeBuffer & 0xf;\r
	156	\r
	157	//\r
	158	// Update Segment Limits for both Code and Data Segment Descriptors\r
	159	//\r
	160	if ((ThunkContext->ThunkAttributes & THUNK_ATTRIBUTE_BIG_REAL_MODE) == 0) {\r
	161	//\r
	162	// Set segment limits to 64KB\r
	163	//\r
	164	RealModeGdt[1].Bits.LimitHigh = 0;\r
	165	RealModeGdt[1].Bits.G = 0;\r
	166	RealModeGdt[2].Bits.LimitHigh = 0;\r
	167	RealModeGdt[2].Bits.G = 0;\r
	168	}\r
	169	\r
	170	//\r
	171	// Update GDTBASE for this thunk context\r
	172	//\r
	173	(VOID*)((UINTN)ThunkContext->RealModeBuffer + m16GdtrBase) = RealModeGdt;\r
	174	\r
	175	//\r
	176	// Update Thunk Attributes\r
	177	//\r
	178	(UINT32)((UINTN)ThunkContext->RealModeBuffer + mThunk16Attr) =\r
	179	ThunkContext->ThunkAttributes;\r
878ddf1f	180	}\r
	181	\r
	182	/**\r
	183	Transfers control to a 16-bit real mode entry point and returns the results.\r
	184	\r
	185	Transfers control to a 16-bit real mode entry point and returns the results.\r
	186	AsmPrepareThunk16() must be called with ThunkContext before this function is\r
	187	used. This function must be called with interrupts disabled.\r
	188	\r
	189	If ThunkContext is NULL, then ASSERT().\r
	190	If AsmPrepareThunk16() was not previously called with ThunkContext, then ASSERT().\r
	191	\r
	192	@param ThunkContext A pointer to the context structure that describes the\r
	193	16-bit real mode code to call.\r
	194	\r
	195	**/\r
	196	VOID\r
	197	EFIAPI\r
	198	AsmThunk16 (\r
	199	IN OUT THUNK_CONTEXT *ThunkContext\r
	200	)\r
	201	{\r
97d92bda	202	IA32_REGISTER_SET *UpdatedRegs;\r
878ddf1f	203	\r
878ddf1f	204	ASSERT (ThunkContext != NULL);\r
97d92bda	205	ASSERT ((UINTN)ThunkContext->RealModeBuffer < 0x100000);\r
	206	ASSERT (ThunkContext->RealModeBufferSize >= m16Size);\r
	207	ASSERT ((UINTN)ThunkContext->RealModeBuffer + m16Size <= 0x100000);\r
878ddf1f	208	\r
97d92bda	209	UpdatedRegs = InternalAsmThunk16 (\r
	210	ThunkContext->RealModeState,\r
	211	ThunkContext->RealModeBuffer\r
	212	);\r
878ddf1f	213	\r
97d92bda	214	CopyMem (ThunkContext->RealModeState, UpdatedRegs, sizeof (*UpdatedRegs));\r
878ddf1f	215	}\r
	216	\r
	217	/**\r
	218	Prepares all structures and code for a 16-bit real mode thunk, transfers\r
	219	control to a 16-bit real mode entry point, and returns the results.\r
	220	\r
	221	Prepares all structures and code for a 16-bit real mode thunk, transfers\r
	222	control to a 16-bit real mode entry point, and returns the results. If the\r
	223	caller only need to perform a single 16-bit real mode thunk, then this\r
	224	service should be used. If the caller intends to make more than one 16-bit\r
	225	real mode thunk, then it is more efficient if AsmPrepareThunk16() is called\r
	226	once and AsmThunk16() can be called for each 16-bit real mode thunk. This\r
	227	function must be called with interrupts disabled.\r
	228	\r
	229	If ThunkContext is NULL, then ASSERT().\r
	230	\r
	231	@param ThunkContext A pointer to the context structure that describes the\r
	232	16-bit real mode code to call.\r
	233	\r
	234	**/\r
	235	VOID\r
	236	EFIAPI\r
	237	AsmPrepareAndThunk16 (\r
	238	IN OUT THUNK_CONTEXT *ThunkContext\r
	239	)\r
	240	{\r
	241	AsmPrepareThunk16 (ThunkContext);\r
	242	AsmThunk16 (ThunkContext);\r
	243	}\r