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source: trunk/kernel/libk/elf.c @ 286

Last change on this file since 286 was 279, checked in by alain, 7 years ago
1) Introduce independant command fields for the various devices in the thread descriptor. 2) Introduce a new dev_pic_enable_ipi() function in the generic PIC device 3) Fix two bugs identified by Maxime in the scheduler initialisation, and in the sched_select(). 4) fix several bugs in the TSAR hal_kentry.S. 5) Introduce a third kgiet segment (besides kdata and kcode) in the TSAR bootloader.
File size: 10.7 KB

Line
1	/*
2	* elf.c - elf parser: find and map process CODE and DATA segments
3	*
4	* Authors Alain Greiner (2016)
5	*
6	* Copyright (c) UPMC Sorbonne Universites
7	*
8	* This file is part of ALMOS-MKH.
9	*
10	* ALMOS-MKH is free software; you can redistribute it and/or modify it
11	* under the terms of the GNU General Public License as published by
12	* the Free Software Foundation; version 2.0 of the License.
13	*
14	* ALMOS-MKH is distributed in the hope that it will be useful, but
15	* WITHOUT ANY WARRANTY; without even the implied warranty of
16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17	* General Public License for more details.
18	*
19	* You should have received a copy of the GNU General Public License
20	* along with ALMOS-MKH; if not, write to the Free Software Foundation,
21	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22	*/
23
24	#include <kernel_config.h>
25	#include <hal_types.h>
26	#include <hal_uspace.h>
27	#include <printk.h>
28	#include <process.h>
29	#include <vseg.h>
30	#include <kmem.h>
31	#include <vfs.h>
32	#include <elf.h>
33	#include <syscalls.h>
34
35	///////////////////////////////////////////////////////////////////
36	// This static function checks the .elf header.
37	// - return true if legal header.
38	// - return false with an error message if illegal header.
39	///////////////////////////////////////////////////////////////////
40	static bool_t elf_isValidHeader(Elf_Ehdr *header)
41	{
42	if((header->e_ident[EI_CLASS] == ELFCLASS)
43	&& (header->e_ident[EI_DATA] == ELFDATA2LSB)
44	&& (header->e_ident[EI_VERSION] == EV_CURRENT)
45	/*
46	&& (header->e_ident[EI_OSABI] == ELFOSABI_NONE)
47	*/
48	&& ((header->e_machine == EM_MIPS) \|\|
49	(header->e_machine == EM_MIPS_RS3_LE) \|\|
50	(header->e_machine == EM_X86_64))
51	&& (header->e_type == ET_EXEC))
52	return true;
53
54	if( header->e_ident[EI_CLASS] != ELFCLASS )
55	printk("\n[ERROR] in %s : Elf is not 32/64-Binary\n", __FUNCTION__ );
56
57	if( header->e_ident[EI_DATA] != ELFDATA2LSB )
58	printk("\n[ERROR] in %s : Elf is not 2's complement, little endian\n", __FUNCTION__ );
59
60	if( header->e_ident[EI_VERSION] != EV_CURRENT )
61	printk("\n[ERROR] in %s : Elf is not in Current Version\n", __FUNCTION__);
62	/*
63	if( header->e_ident[EI_OSABI] != ELFOSABI_NONE )
64	printk("\n[ERROR] in %s : Unexpected Elf ABI, need UNIX System V ABI\n", __FUNCTION__ );
65	*/
66	if( (header->e_machine != EM_MIPS) &&
67	(header->e_machine != EM_MIPS_RS3_LE) &&
68	(header->e_machine != EM_X86_64) )
69	printk("\n[ERROR] in %s : unexpected core / accept only MIPS or x86_64\n", __FUNCTION__ );
70
71	if( header->e_type != ET_EXEC )
72	printk("\n[ERROR] in %s : Elf is not executable binary\n", __FUNCTION__ );
73
74	return false;
75	}
76
77	///////////////////////////////////////////////////////////////////////////////////////
78	// This function loads the .elf header in the buffer allocated by the caller.
79	///////////////////////////////////////////////////////////////////////////////////////
80	// @ file : extended pointer on the remote file descriptor.
81	// @ buffer : pointer on buffer allocated by the caller.
82	// @ size : number of bytes to read.
83	///////////////////////////////////////////////////////////////////////////////////////
84	static error_t elf_header_load( xptr_t file_xp,
85	void * buffer,
86	uint32_t size )
87	{
88	uint32_t count;
89
90	// load .elf header
91	count = vfs_move( true, // to_buffer
92	false, // is_user
93	file_xp,
94	buffer,
95	size );
96
97	if( count != size )
98	{
99	printk("\n[ERROR] in %s : cannot read ELF header size : %d / done = %d\n",
100	__FUNCTION__ , size , count );
101	return -1;
102	}
103
104	Elf_Ehdr * header = (Elf_Ehdr *)buffer;
105
106	if( (header->e_ident[EI_MAG0] != ELFMAG0) \|\|
107	(header->e_ident[EI_MAG1] != ELFMAG1) \|\|
108	(header->e_ident[EI_MAG2] != ELFMAG2) \|\|
109	(header->e_ident[EI_MAG3] != ELFMAG3) )
110	{
111	printk("\n[ERROR] in %s : file %s not in ELF format\n", __FUNCTION__ );
112	return -1;
113	}
114
115	if( !(elf_isValidHeader( header ) ) )
116	{
117	printk("\n[ERROR] in %s : not supported Elf\n", __FUNCTION__ );
118	return -1;
119	}
120	return 0;
121
122	} // end elf_header_load()
123
124	///////////////////////////////////////////////////////////////////////////////////////
125	// This function registers in the process VMM the CODE and DATA segments.
126	///////////////////////////////////////////////////////////////////////////////////////
127	// @ file : extended pointer on the remote file descriptor.
128	// @ segs_base : local pointer on buffer containing the segments descriptors array
129	// @ segs_nr : number of segments in segment descriptors array.
130	// @ process : local pointer on process descriptor.
131	///////////////////////////////////////////////////////////////////////////////////////
132	static error_t elf_segments_load( xptr_t file_xp,
133	void * segs_base,
134	uint32_t nb_segs,
135	process_t * process )
136	{
137	error_t error;
138	uint32_t index;
139	uint32_t file_size;
140	uint32_t mem_size;
141	intptr_t start;
142	uint32_t type;
143	uint32_t flags;
144	uint32_t offset;
145	vseg_t * vseg;
146
147	Elf_Phdr * seg_ptr = (Elf_Phdr *)segs_base;
148
149	// loop on segments
150	for( index = 0 ; index < nb_segs ; index++ , seg_ptr++ )
151	{
152	if( seg_ptr->p_type != PT_LOAD)
153	continue;
154
155	// get segment attributes
156	start = seg_ptr->p_vaddr;
157	offset = seg_ptr->p_offset;
158	file_size = seg_ptr->p_filesz;
159	mem_size = seg_ptr->p_memsz;
160	flags = seg_ptr->p_flags;
161
162	// check alignment
163	if( start & CONFIG_PPM_PAGE_MASK )
164	{
165	printk("\n[WARNING] in %s : segment base not aligned = %x\n",
166	__FUNCTION__, start );
167	}
168
169	// check size
170	if( file_size != mem_size )
171	{
172	printk("\n[WARNING] in %s : base = %x / mem_size = %x / file_size = %x\n",
173	__FUNCTION__, start , mem_size , file_size);
174	}
175
176	// set seek on segment base in file
177	error = vfs_lseek( file_xp,
178	offset,
179	SEEK_SET,
180	NULL );
181
182	if( error )
183	{
184	printk("\n[ERROR] in %s : failed to seek\n", __FUNCTION__ );
185	return -1;
186	}
187
188	if( flags & PF_X ) // found CODE segment
189	{
190	type = VSEG_TYPE_CODE;
191	process->vmm.code_vpn_base = start >> CONFIG_PPM_PAGE_SHIFT;
192
193	elf_dmsg("\n[INFO] %s : found CODE vseg / base = %x / size = %x\n",
194	__FUNCTION__ , start , mem_size );
195	}
196	else // found DATA segment
197	{
198	type = VSEG_TYPE_DATA;
199	process->vmm.data_vpn_base = start >> CONFIG_PPM_PAGE_SHIFT;
200
201	elf_dmsg("\n[INFO] %s : found DATA vseg / base = %x / size = %x\n",
202	__FUNCTION__, start , mem_size );
203	}
204
205	// register vseg in VMM
206	vseg = (vseg_t *)vmm_create_vseg( process,
207	start,
208	mem_size,
209	type );
210	if( vseg == NULL )
211	{
212	printk("\n[ERROR] in %s : cannot map segment / base = %x / size = %x\n",
213	__FUNCTION__ , start , mem_size );
214	return -1;
215	}
216
217	vfs_file_count_up( file_xp );
218	}
219
220	return 0;
221
222	} // end elf_segments_load()
223
224	///////////////////////////////////////////////
225	error_t elf_load_process( char * pathname,
226	process_t * process)
227	{
228	kmem_req_t req; // kmem request for program header
229	Elf_Ehdr header; // local buffer for .elf header
230	void * segs_base; // pointer on buffer for segment descriptors array
231	uint32_t segs_size; // size of buffer for segment descriptors array
232	xptr_t file_xp; // extended pointer on created file descriptor
233	uint32_t file_id; // file descriptor index (unused)
234	uint32_t count; // bytes counter
235	error_t error;
236
237	elf_dmsg("\n[INFO] %s : enters for <%s>\n", __FUNCTION__ , pathname );
238
239	// avoid GCC warning
240	file_xp = XPTR_NULL;
241	file_id = -1;
242
243	// open file
244	error = vfs_open( process->vfs_cwd_xp,
245	pathname,
246	O_RDONLY,
247	0,
248	&file_xp,
249	&file_id );
250	if( error )
251	{
252	printk("\n[ERROR] in %s : failed to open file %s\n", __FUNCTION__ , pathname );
253	return -1;
254	}
255
256	elf_dmsg("\n[INFO] %s : file <%s> open\n", __FUNCTION__ , pathname );
257
258	// load header in local buffer
259	error = elf_header_load( file_xp ,
260	&header,
261	sizeof(Elf_Ehdr) );
262	if( error )
263	{
264	printk("\n[ERROR] in %s : cannot get header file %s\n", __FUNCTION__ , pathname );
265	vfs_close( file_xp , file_id );
266	return -1;
267	}
268
269	elf_dmsg("\n[INFO] %s : loaded elf header for %s\n", __FUNCTION__ , pathname );
270
271	if( header.e_phnum == 0 )
272	{
273	printk("\n[ERROR] in %s : no segments found\n", __FUNCTION__ );
274	vfs_close( file_xp , file_id );
275	return -1;
276	}
277
278	// compute buffer size for segment descriptors array
279	segs_size = sizeof(Elf_Phdr) * header.e_phnum;
280
281	// allocate memory for segment descriptors array
282	req.type = KMEM_GENERIC;
283	req.size = segs_size;
284	req.flags = AF_KERNEL;
285	segs_base = kmem_alloc( &req );
286
287	if( segs_base == NULL )
288	{
289	printk("\n[ERROR] in %s : no memory for segment descriptors\n", __FUNCTION__ );
290	vfs_close( file_xp , file_id );
291	return -1;
292	}
293
294	// set seek pointer in file descriptor to access segment descriptors array
295	error = vfs_lseek( file_xp , header.e_phoff, SEEK_SET , NULL );
296
297	if( error )
298	{
299	printk("\n[ERROR] in %s : cannot seek for descriptors array\n", __FUNCTION__ );
300	vfs_close( file_xp , file_id );
301	req.ptr = segs_base;
302	kmem_free( &req );
303	return -1;
304	}
305
306	// load seg descriptors array to local buffer
307	count = vfs_move( true, // to_buffer
308	false, // is_user
309	file_xp,
310	segs_base,
311	segs_size );
312
313	if( count != segs_size )
314	{
315	printk("\n[ERROR] in %s : cannot read segments descriptors\n", __FUNCTION__ );
316	vfs_close( file_xp , file_id );
317	req.ptr = segs_base;
318	kmem_free( &req );
319	return -1;
320	}
321
322	elf_dmsg("\n[INFO] %s loaded segments descriptors for %s \n", __FUNCTION__ , pathname );
323
324	// register loadable segments in process VMM
325	error = elf_segments_load( file_xp,
326	segs_base,
327	header.e_phnum,
328	process );
329	if( error )
330	{
331	vfs_close( file_xp , file_id );
332	req.ptr = segs_base;
333	kmem_free( &req );
334	return -1;
335	}
336
337	// register process entry point in VMM
338	process->vmm.entry_point = (intptr_t)header.e_entry;
339
340	// register extended pointer on .elf file descriptor
341	process->vfs_bin_xp = file_xp;
342
343	// release allocated memory for program header
344	req.ptr = segs_base;
345	kmem_free(&req);
346
347	elf_dmsg("\n[INFO] %s successfully completed / entry point = %x for %s]\n",
348	__FUNCTION__, (uint32_t) header.e_entry , pathname );
349
350	return 0;
351
352	} // end elf_load_process()
353

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