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source: trunk/kernel/libk/elf.c @ 655

Last change on this file since 655 was 651, checked in by alain, 5 years ago
1) Improve the VMM MMAP allocator: implement the "buddy" algorithm to allocate only aligned blocks. 2) fix a bug in the pthread_join() / pthread_exit() mmechanism.
File size: 11.1 KB

Line
1	/*
2	* elf.c - elf parser: find and map process CODE and DATA segments
3	*
4	* Authors Alain Greiner (2016,2017,2018,2019)
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_kernel_types.h>
26	#include <hal_special.h>
27	#include <hal_uspace.h>
28	#include <printk.h>
29	#include <process.h>
30	#include <thread.h>
31	#include <mapper.h>
32	#include <vseg.h>
33	#include <kmem.h>
34	#include <vfs.h>
35	#include <elf.h>
36	#include <syscalls.h>
37
38	///////////////////////////////////////////////////////////////////
39	// This static function checks the .elf header.
40	// - return true if legal header.
41	// - return false with an error message if illegal header.
42	///////////////////////////////////////////////////////////////////
43	static bool_t elf_isValidHeader(Elf_Ehdr *header)
44	{
45	if((header->e_ident[EI_CLASS] == ELFCLASS)
46	&& (header->e_ident[EI_DATA] == ELFDATA2LSB)
47	&& (header->e_ident[EI_VERSION] == EV_CURRENT)
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_machine != EM_MIPS) &&
64	(header->e_machine != EM_MIPS_RS3_LE) &&
65	(header->e_machine != EM_X86_64) )
66	printk("\n[ERROR] in %s : unexpected core / accept only MIPS or x86_64\n", __FUNCTION__ );
67
68	if( header->e_type != ET_EXEC )
69	printk("\n[ERROR] in %s : Elf is not executable binary\n", __FUNCTION__ );
70
71	return false;
72	}
73
74	///////////////////////////////////////////////////////////////////////////////////////
75	// This function loads the .elf header in the buffer allocated by the caller.
76	///////////////////////////////////////////////////////////////////////////////////////
77	// @ file : extended pointer on the remote file descriptor.
78	// @ buffer : pointer on buffer allocated by the caller.
79	// @ size : number of bytes to read.
80	///////////////////////////////////////////////////////////////////////////////////////
81	static error_t elf_header_load( xptr_t file_xp,
82	void * buffer,
83	uint32_t size )
84	{
85	error_t error;
86	xptr_t buf_xp;
87
88	buf_xp = XPTR( local_cxy , buffer );
89
90	// load .elf header
91	error = vfs_kernel_move( true, // to_buffer
92	file_xp,
93	buf_xp,
94	size );
95
96	if( error )
97	{
98	printk("\n[ERROR] in %s : cannot read ELF header size : %d\n",
99	__FUNCTION__ , size );
100	return -1;
101	}
102
103	Elf_Ehdr * header = (Elf_Ehdr *)buffer;
104
105	if( (header->e_ident[EI_MAG0] != ELFMAG0) \|\|
106	(header->e_ident[EI_MAG1] != ELFMAG1) \|\|
107	(header->e_ident[EI_MAG2] != ELFMAG2) \|\|
108	(header->e_ident[EI_MAG3] != ELFMAG3) )
109	{
110	printk("\n[ERROR] in %s : file not in ELF format\n", __FUNCTION__ );
111	return -1;
112	}
113
114	if( !(elf_isValidHeader( header ) ) )
115	{
116	printk("\n[ERROR] in %s : not supported Elf\n", __FUNCTION__ );
117	return -1;
118	}
119	return 0;
120
121	} // end elf_header_load()
122
123	///////////////////////////////////////////////////////////////////////////////////////
124	// This function registers in the process VMM the CODE and DATA segments.
125	///////////////////////////////////////////////////////////////////////////////////////
126	// @ file : extended pointer on the remote file descriptor.
127	// @ segs_base : local pointer on buffer containing the segments descriptors array
128	// @ segs_nr : number of segments in segment descriptors array.
129	// @ process : local pointer on process descriptor.
130	///////////////////////////////////////////////////////////////////////////////////////
131	static error_t elf_segments_register( xptr_t file_xp,
132	void * segs_base,
133	uint32_t nb_segs,
134	process_t * process )
135	{
136	uint32_t index;
137	intptr_t file_size;
138	intptr_t mem_size;
139	intptr_t file_offset;
140	intptr_t vbase;
141	uint32_t type;
142	uint32_t flags;
143	vseg_t * vseg;
144
145	Elf_Phdr * seg_ptr = (Elf_Phdr *)segs_base;
146
147	// loop on segments
148	for( index = 0 ; index < nb_segs ; index++ , seg_ptr++ )
149	{
150	if( seg_ptr->p_type != PT_LOAD)
151	continue;
152
153	// get segment attributes
154	vbase = seg_ptr->p_vaddr; // vseg base vaddr
155	mem_size = seg_ptr->p_memsz; // actual vseg size
156	file_offset = seg_ptr->p_offset; // vseg offset in .elf file
157	file_size = seg_ptr->p_filesz; // vseg size in .elf file
158	flags = seg_ptr->p_flags;
159
160	if( flags & PF_X ) // found CODE segment
161	{
162	type = VSEG_TYPE_CODE;
163	process->vmm.code_vpn_base = vbase >> CONFIG_PPM_PAGE_SHIFT;
164	}
165	else // found DATA segment
166	{
167	type = VSEG_TYPE_DATA;
168	process->vmm.data_vpn_base = vbase >> CONFIG_PPM_PAGE_SHIFT;
169	}
170
171	// get .elf file descriptor cluster and local pointer
172	cxy_t file_cxy = GET_CXY( file_xp );
173	vfs_file_t * file_ptr = (vfs_file_t *)GET_PTR( file_xp );
174
175	// get local pointer on .elf file mapper
176	mapper_t * mapper_ptr = (mapper_t *)hal_remote_lpt( XPTR( file_cxy ,
177	&file_ptr->mapper ) );
178	// register vseg in VMM
179	vseg = (vseg_t *)vmm_create_vseg( process,
180	type,
181	vbase,
182	mem_size,
183	file_offset,
184	file_size,
185	XPTR( file_cxy , mapper_ptr ),
186	local_cxy );
187	if( vseg == NULL )
188	{
189	printk("\n[ERROR] in %s : cannot map segment / base = %x / size = %x\n",
190	__FUNCTION__ , vbase , mem_size );
191	return -1;
192	}
193
194	// update reference counter in file descriptor
195	vfs_file_count_up( file_xp );
196
197	#if DEBUG_ELF_LOAD
198	uint32_t cycle = (uint32_t)hal_get_cycles();
199	thread_t * this = CURRENT_THREAD;
200	if( DEBUG_ELF_LOAD < cycle )
201	printk("\n[%s] thread[%x,%x] found %s vseg / base %x / size %x\n"
202	" file_size %x / file_offset %x / mapper_xp %l / cycle %d\n",
203	__FUNCTION__ , this->process->pid, this->trdid,
204	vseg_type_str(vseg->type) , vseg->min , vseg->max - vseg->min ,
205	vseg->file_size , vseg->file_offset , vseg->mapper_xp, cycle );
206	#endif
207
208	}
209
210	return 0;
211
212	} // end elf_segments_register()
213
214	//////////////////////////////////////////////
215	error_t elf_load_process( xptr_t file_xp,
216	process_t * process )
217	{
218	uint32_t new_offset; // unused, required by vfs_lseek()
219	kmem_req_t req; // kmem request for program header
220	Elf_Ehdr header; // local buffer for .elf header
221	void * segs_base; // pointer on buffer for segment descriptors array
222	uint32_t segs_size; // size of buffer for segment descriptors array
223	char name[CONFIG_VFS_MAX_NAME_LENGTH];
224	error_t error;
225
226	// get file name for error reporting and debug
227	cxy_t file_cxy = GET_CXY( file_xp );
228	vfs_file_t * file_ptr = GET_PTR( file_xp );
229	vfs_inode_t * inode = hal_remote_lpt( XPTR( file_cxy , &file_ptr->inode ) );
230	vfs_inode_get_name( XPTR( file_cxy , inode ) , name );
231
232	#if DEBUG_ELF_LOAD
233	uint32_t cycle = (uint32_t)hal_get_cycles();
234	thread_t * this = CURRENT_THREAD;
235	if( DEBUG_ELF_LOAD < cycle )
236	printk("\n[%s] thread[%x,%x] enter for <%s> / cycle %d\n",
237	__FUNCTION__, this->process->pid, this->trdid, name, cycle );
238	#endif
239
240	// load header in local buffer
241	error = elf_header_load( file_xp ,
242	&header,
243	sizeof(Elf_Ehdr) );
244	if( error )
245	{
246	printk("\n[ERROR] in %s : cannot get header for <%s>\n", __FUNCTION__ , name );
247	return -1;
248	}
249
250	#if (DEBUG_ELF_LOAD & 1)
251	if( DEBUG_ELF_LOAD < cycle )
252	printk("\n[%s] loaded elf header for <%s>\n", __FUNCTION__ , name );
253	#endif
254
255	if( header.e_phnum == 0 )
256	{
257	printk("\n[ERROR] in %s : no segments found\n", __FUNCTION__ );
258	return -1;
259	}
260
261	// compute buffer size for segment descriptors array
262	segs_size = sizeof(Elf_Phdr) * header.e_phnum;
263
264	// allocate memory for segment descriptors array
265	req.type = KMEM_KCM;
266	req.order = bits_log2(segs_size);
267	req.flags = AF_KERNEL;
268	segs_base = kmem_alloc( &req );
269
270	if( segs_base == NULL )
271	{
272	printk("\n[ERROR] in %s : no memory for segment descriptors\n", __FUNCTION__ );
273	return -1;
274	}
275
276	// set seek pointer in file descriptor to access segment descriptors array
277	error = vfs_lseek( file_xp , header.e_phoff, SEEK_SET , &new_offset );
278
279	if( error )
280	{
281	printk("\n[ERROR] in %s : cannot seek for descriptors array\n", __FUNCTION__ );
282	req.ptr = segs_base;
283	kmem_free( &req );
284	return -1;
285	}
286
287	#if (DEBUG_ELF_LOAD & 1)
288	if( DEBUG_ELF_LOAD < cycle )
289	printk("\n[%s] segments array allocated for <%s>\n", __FUNCTION__ , name );
290	#endif
291
292	// load seg descriptors array to local buffer
293	error = vfs_kernel_move( true, // to_buffer
294	file_xp,
295	XPTR( local_cxy , segs_base ),
296	segs_size );
297
298	if( error )
299	{
300	printk("\n[ERROR] in %s : cannot read segments descriptors\n", __FUNCTION__ );
301	req.ptr = segs_base;
302	kmem_free( &req );
303	return -1;
304	}
305
306	#if (DEBUG_ELF_LOAD & 1)
307	if( DEBUG_ELF_LOAD < cycle )
308	printk("\n[%s] loaded segments descriptors for <%s>\n", __FUNCTION__ , name );
309	#endif
310
311	// register loadable segments in process VMM
312	error = elf_segments_register( file_xp,
313	segs_base,
314	header.e_phnum,
315	process );
316	if( error )
317	{
318	req.ptr = segs_base;
319	kmem_free( &req );
320	return -1;
321	}
322
323	// register process entry point in VMM
324	process->vmm.entry_point = (intptr_t)header.e_entry;
325
326	// register extended pointer on .elf file descriptor
327	process->vfs_bin_xp = file_xp;
328
329	// release allocated memory for program header
330	req.ptr = segs_base;
331	kmem_free(&req);
332
333	#if DEBUG_ELF_LOAD
334	cycle = (uint32_t)hal_get_cycles();
335	if( DEBUG_ELF_LOAD < cycle )
336	printk("\n[%s] thread[%x,%x] exit for <%s> / entry_point %x / cycle %d\n",
337	__FUNCTION__, this->process->pid, this->trdid, name, header.e_entry, cycle );
338	#endif
339
340	return 0;
341
342	} // end elf_load_process()
343

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