[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
// Include common header file for this module.\r
//\r
#include <BaseLibInternals.h>\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
e1f414b6	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	// Include common header file for this module.\r
	19	//\r
f734a10a A	20	#include <BaseLibInternals.h>\r
f734a10a A	21	\r
e1f414b6	22	\r
	23	//\r
	24	// Byte packed structure for a segment descriptor in a GDT/LDT\r
	25	//\r
	26	typedef union {\r
	27	struct {\r
	28	UINT32 LimitLow:16;\r
	29	UINT32 BaseLow:16;\r
	30	UINT32 BaseMid:8;\r
	31	UINT32 Type:4;\r
	32	UINT32 S:1;\r
	33	UINT32 DPL:2;\r
	34	UINT32 P:1;\r
	35	UINT32 LimitHigh:4;\r
	36	UINT32 AVL:1;\r
	37	UINT32 L:1;\r
	38	UINT32 DB:1;\r
	39	UINT32 G:1;\r
	40	UINT32 BaseHigh:8;\r
	41	} Bits;\r
	42	UINT64 Uint64;\r
	43	} IA32_SEGMENT_DESCRIPTOR;\r
	44	\r
	45	extern CONST UINT8 m16Start;\r
	46	extern CONST UINT16 m16Size;\r
	47	extern CONST UINT16 mThunk16Attr;\r
	48	extern CONST UINT16 m16Gdt;\r
	49	extern CONST UINT16 m16GdtrBase;\r
	50	extern CONST UINT16 mTransition;\r
	51	\r
	52	/**\r
	53	Invokes 16-bit code in big real mode and returns the updated register set.\r
	54	\r
	55	This function transfers control to the 16-bit code specified by CS:EIP using\r
	56	the stack specified by SS:ESP in RegisterSet. The updated registers are saved\r
	57	on the real mode stack and the starting address of the save area is returned.\r
	58	\r
	59	@param RegisterSet Values of registers before invocation of 16-bit code.\r
	60	@param Transition Pointer to the transition code under 1MB.\r
	61	\r
	62	@return The pointer to a IA32_REGISTER_SET structure containing the updated\r
	63	register values.\r
	64	\r
	65	**/\r
	66	IA32_REGISTER_SET *\r
	67	EFIAPI\r
	68	InternalAsmThunk16 (\r
	69	IN IA32_REGISTER_SET *RegisterSet,\r
	70	IN OUT VOID *Transition\r
	71	);\r
	72	\r
	73	/**\r
	74	Retrieves the properties for 16-bit thunk functions.\r
	75	\r
	76	Computes the size of the buffer and stack below 1MB required to use the\r
	77	AsmPrepareThunk16(), AsmThunk16() and AsmPrepareAndThunk16() functions. This\r
	78	buffer size is returned in RealModeBufferSize, and the stack size is returned\r
	79	in ExtraStackSize. If parameters are passed to the 16-bit real mode code,\r
	80	then the actual minimum stack size is ExtraStackSize plus the maximum number\r
	81	of bytes that need to be passed to the 16-bit real mode code.\r
	82	\r
	83	If RealModeBufferSize is NULL, then ASSERT().\r
	84	If ExtraStackSize is NULL, then ASSERT().\r
	85	\r
86	@param RealModeBufferSize A pointer to the size of the buffer below 1MB\r
87	required to use the 16-bit thunk functions.\r
88	@param ExtraStackSize A pointer to the extra size of stack below 1MB\r
89	that the 16-bit thunk functions require for\r
90	temporary storage in the transition to and from\r
91	16-bit real mode.\r
92	\r
93	**/\r
94	VOID\r
95	EFIAPI\r
96	AsmGetThunk16Properties (\r
97	OUT UINT32 *RealModeBufferSize,\r
98	OUT UINT32 *ExtraStackSize\r
99	)\r
100	{\r
101	ASSERT (RealModeBufferSize != NULL);\r
102	ASSERT (ExtraStackSize != NULL);\r
103	\r
104	*RealModeBufferSize = m16Size;\r
105	\r
106	//\r
107	// Extra 4 bytes for return address, and another 4 bytes for mode transition\r
108	//\r
109	*ExtraStackSize = sizeof (IA32_DWORD_REGS) + 8;\r
110	}\r
111	\r
112	/**\r
113	Prepares all structures a code required to use AsmThunk16().\r
114	\r
115	Prepares all structures and code required to use AsmThunk16().\r
116	\r
117	If ThunkContext is NULL, then ASSERT().\r
118	\r
119	@param ThunkContext A pointer to the context structure that describes the\r
120	16-bit real mode code to call.\r
121	\r
122	**/\r
123	VOID\r
124	EFIAPI\r
125	AsmPrepareThunk16 (\r
126	OUT THUNK_CONTEXT *ThunkContext\r
127	)\r
128	{\r
129	IA32_SEGMENT_DESCRIPTOR *RealModeGdt;\r
130	\r
131	ASSERT (ThunkContext != NULL);\r
132	ASSERT ((UINTN)ThunkContext->RealModeBuffer < 0x100000);\r
133	ASSERT (ThunkContext->RealModeBufferSize >= m16Size);\r
134	ASSERT ((UINTN)ThunkContext->RealModeBuffer + m16Size <= 0x100000);\r
135	\r
136	CopyMem (ThunkContext->RealModeBuffer, &m16Start, m16Size);\r
137	\r
138	//\r
139	// Point RealModeGdt to the GDT to be used in transition\r
140	//\r
141	// RealModeGdt[0]: Reserved as NULL descriptor\r
142	// RealModeGdt[1]: Code Segment\r
143	// RealModeGdt[2]: Data Segment\r
144	// RealModeGdt[3]: Call Gate\r
145	//\r
146	RealModeGdt = (IA32_SEGMENT_DESCRIPTOR*)(\r
147	(UINTN)ThunkContext->RealModeBuffer + m16Gdt);\r
148	\r
149	//\r
150	// Update Code & Data Segment Descriptor\r
151	//\r
152	RealModeGdt[1].Bits.BaseLow =\r
153	(UINT32)(UINTN)ThunkContext->RealModeBuffer & ~0xf;\r
154	RealModeGdt[1].Bits.BaseMid =\r
155	(UINT32)(UINTN)ThunkContext->RealModeBuffer >> 16;\r
156	\r
157	//\r
158	// Update transition code entry point offset\r
159	//\r
160	(UINT32)((UINTN)ThunkContext->RealModeBuffer + mTransition) +=\r
161	(UINT32)(UINTN)ThunkContext->RealModeBuffer & 0xf;\r
162	\r
163	//\r
164	// Update Segment Limits for both Code and Data Segment Descriptors\r
165	//\r
166	if ((ThunkContext->ThunkAttributes & THUNK_ATTRIBUTE_BIG_REAL_MODE) == 0) {\r
167	//\r
168	// Set segment limits to 64KB\r
169	//\r
170	RealModeGdt[1].Bits.LimitHigh = 0;\r
171	RealModeGdt[1].Bits.G = 0;\r
172	RealModeGdt[2].Bits.LimitHigh = 0;\r
173	RealModeGdt[2].Bits.G = 0;\r
174	}\r
175	\r
176	//\r
177	// Update GDTBASE for this thunk context\r
178	//\r
179	(VOID*)((UINTN)ThunkContext->RealModeBuffer + m16GdtrBase) = RealModeGdt;\r
180	\r
181	//\r
182	// Update Thunk Attributes\r
183	//\r
184	(UINT32)((UINTN)ThunkContext->RealModeBuffer + mThunk16Attr) =\r
185	ThunkContext->ThunkAttributes;\r
186	}\r
187	\r
188	/**\r
189	Transfers control to a 16-bit real mode entry point and returns the results.\r
190	\r
191	Transfers control to a 16-bit real mode entry point and returns the results.\r
192	AsmPrepareThunk16() must be called with ThunkContext before this function is\r
193	used. This function must be called with interrupts disabled.\r
194	\r
195	If ThunkContext is NULL, then ASSERT().\r
196	If AsmPrepareThunk16() was not previously called with ThunkContext, then ASSERT().\r
197	\r
198	@param ThunkContext A pointer to the context structure that describes the\r
199	16-bit real mode code to call.\r
200	\r
201	**/\r
202	VOID\r
203	EFIAPI\r
204	AsmThunk16 (\r
205	IN OUT THUNK_CONTEXT *ThunkContext\r
206	)\r
207	{\r
208	IA32_REGISTER_SET *UpdatedRegs;\r
209	\r
210	ASSERT (ThunkContext != NULL);\r
211	ASSERT ((UINTN)ThunkContext->RealModeBuffer < 0x100000);\r
212	ASSERT (ThunkContext->RealModeBufferSize >= m16Size);\r
213	ASSERT ((UINTN)ThunkContext->RealModeBuffer + m16Size <= 0x100000);\r
214	\r
215	UpdatedRegs = InternalAsmThunk16 (\r
216	ThunkContext->RealModeState,\r
217	ThunkContext->RealModeBuffer\r
218	);\r
219	\r
220	CopyMem (ThunkContext->RealModeState, UpdatedRegs, sizeof (*UpdatedRegs));\r
221	}\r
222	\r
223	/**\r
224	Prepares all structures and code for a 16-bit real mode thunk, transfers\r
225	control to a 16-bit real mode entry point, and returns the results.\r
226	\r
227	Prepares all structures and code for a 16-bit real mode thunk, transfers\r
228	control to a 16-bit real mode entry point, and returns the results. If the\r
229	caller only need to perform a single 16-bit real mode thunk, then this\r
230	service should be used. If the caller intends to make more than one 16-bit\r
231	real mode thunk, then it is more efficient if AsmPrepareThunk16() is called\r
232	once and AsmThunk16() can be called for each 16-bit real mode thunk. This\r
233	function must be called with interrupts disabled.\r
234	\r
235	If ThunkContext is NULL, then ASSERT().\r
236	\r
237	@param ThunkContext A pointer to the context structure that describes the\r
238	16-bit real mode code to call.\r
239	\r
240	**/\r
241	VOID\r
242	EFIAPI\r
243	AsmPrepareAndThunk16 (\r
244	IN OUT THUNK_CONTEXT *ThunkContext\r
245	)\r
246	{\r
247	AsmPrepareThunk16 (ThunkContext);\r
248	AsmThunk16 (ThunkContext);\r
249	}\r