source: trunk/kernel/syscalls/sys_read.c@ 640

Last change on this file since 640 was 635, checked in by alain, 7 years ago

This version is a major evolution: The physical memory allocators,
defined in the kmem.c, ppm.c, and kcm.c files have been modified
to support remote accesses. The RPCs that were previously user
to allocate physical memory in a remote cluster have been removed.
This has been done to cure a dead-lock in case of concurrent page-faults.

This version 2.2 has been tested on a (4 clusters / 2 cores per cluster)
TSAR architecture, for both the "sort" and the "fft" applications.
File size: 9.3 KB
Line 
1/*
2 * sys_read.c - Kernel function implementing the "read" system call.
3 *
4 * Author 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_vmm.h>
27#include <hal_uspace.h>
28#include <hal_irqmask.h>
29#include <hal_special.h>
30#include <errno.h>
31#include <vfs.h>
32#include <vmm.h>
33#include <thread.h>
34#include <printk.h>
35#include <process.h>
36
37
38extern uint32_t enter_sys_read;
39extern uint32_t enter_devfs_read;
40extern uint32_t enter_txt_read;
41extern uint32_t enter_chdev_cmd_read;
42extern uint32_t enter_chdev_server_read;
43extern uint32_t enter_tty_cmd_read;
44extern uint32_t enter_tty_isr_read;
45extern uint32_t exit_tty_isr_read;
46extern uint32_t exit_tty_cmd_read;
47extern uint32_t exit_chdev_server_read;
48extern uint32_t exit_chdev_cmd_read;
49extern uint32_t exit_txt_read;
50extern uint32_t exit_devfs_read;
51extern uint32_t exit_sys_read;
52
53
54/////////////////////////////////
55int sys_read( uint32_t file_id,
56 void * vaddr,
57 uint32_t count )
58{
59 error_t error;
60 vseg_t * vseg; // required for user space checking
61 xptr_t file_xp; // remote file extended pointer
62 vfs_file_t * file_ptr; // remote file local pointer
63 cxy_t file_cxy; // remote file cluster identifier
64 uint32_t file_type; // file type
65 uint32_t file_attr; // file_attribute
66 uint32_t nbytes; // number of bytes actually read
67 reg_t save_sr; // required to enable IRQs during syscall
68
69 thread_t * this = CURRENT_THREAD;
70 process_t * process = this->process;
71 xptr_t process_owner_xp = process->owner_xp;
72
73#if (DEBUG_SYS_READ || CONFIG_INSTRUMENTATION_SYSCALLS)
74uint64_t tm_start = hal_get_cycles();
75#endif
76
77#if DEBUG_SYS_READ
78if( DEBUG_SYS_READ < tm_start )
79printk("\n[%s] thread[%x,%x] enter / vaddr %x / count %d / cycle %d\n",
80__FUNCTION__, process->pid, this->trdid, vaddr, count, (uint32_t)tm_start );
81#endif
82
83#if (DEBUG_SYS_READ & 1)
84enter_sys_read = (uint32_t)tm_start;
85#endif
86
87 // check file_id argument
88 if( file_id >= CONFIG_PROCESS_FILE_MAX_NR )
89 {
90
91#if DEBUG_SYSCALLS_ERROR
92printk("\n[ERROR] in %s : thread[%x,%x] illegal file descriptor index %d\n",
93__FUNCTION__ , process->pid, this->trdid, file_id );
94#endif
95 this->errno = EBADFD;
96 return -1;
97 }
98
99 // check user buffer in user space
100 error = vmm_get_vseg( process , (intptr_t)vaddr , &vseg );
101
102 if ( error )
103 {
104
105#if DEBUG_SYSCALLS_ERROR
106printk("\n[ERROR] in %s : thread[%x,%x] user buffer unmapped %x\n",
107__FUNCTION__ , process->pid, this->trdid, (intptr_t)vaddr );
108#endif
109 this->errno = EINVAL;
110 return -1;
111 }
112
113 // get extended pointer on remote file descriptor
114 file_xp = process_fd_get_xptr( process , file_id );
115
116 if( file_xp == XPTR_NULL )
117 {
118
119#if DEBUG_SYSCALLS_ERROR
120printk("\n[ERROR] in %s : thread[%x,%x] undefined fd_id %d\n",
121__FUNCTION__, process->pid, this->trdid, file_id );
122#endif
123 this->errno = EBADFD;
124 return -1;
125 }
126
127 // get file descriptor cluster and local pointer
128 file_ptr = GET_PTR( file_xp );
129 file_cxy = GET_CXY( file_xp );
130
131 // get file type and attributes
132 file_type = hal_remote_l32( XPTR( file_cxy , &file_ptr->type ) );
133 file_attr = hal_remote_l32( XPTR( file_cxy , &file_ptr->attr ) );
134
135 // enable IRQs
136 hal_enable_irq( &save_sr );
137
138 // action depend on file type
139 if( file_type == INODE_TYPE_FILE ) // read from file mapper
140 {
141 // check file readable
142 if( (file_attr & FD_ATTR_READ_ENABLE) == 0 )
143 {
144
145#if DEBUG_SYSCALLS_ERROR
146printk("\n[ERROR] in %s : thread[%x,%x] file %d not readable\n",
147__FUNCTION__, process->pid, this->trdid, file_id );
148#endif
149 hal_restore_irq( save_sr );
150 this->errno = EBADFD;
151 return -1;
152 }
153
154 // move count bytes from mapper
155 nbytes = vfs_user_move( true, // from mapper to buffer
156 file_xp,
157 vaddr,
158 count );
159 if( nbytes != count )
160 {
161
162#if DEBUG_SYSCALLS_ERROR
163printk("\n[ERROR] in %s : thread[%x,‰x] cannot read %d bytes from file %d\n",
164__FUNCTION__, process->pid, this->trdid, count, file_id );
165#endif
166 this->errno = EIO;
167 hal_restore_irq( save_sr );
168 return -1;
169 }
170 }
171 else if( file_type == INODE_TYPE_DEV ) // read from TXT device
172 {
173 // get cluster and pointers on TXT_RX chdev
174 xptr_t chdev_xp = chdev_from_file( file_xp );
175 cxy_t chdev_cxy = GET_CXY( chdev_xp );
176 chdev_t * chdev_ptr = GET_PTR( chdev_xp );
177
178 volatile xptr_t txt_owner_xp;
179 uint32_t iter = 0;
180
181 while( 1 )
182 {
183 // extended pointer on TXT owner process
184 txt_owner_xp = hal_remote_l64( XPTR( chdev_cxy , &chdev_ptr->ext.txt.owner_xp ) );
185
186 // check TXT_RX ownership
187 if ( process_owner_xp != txt_owner_xp )
188 {
189 if( (iter & 0xFFF) == 0 )
190 printk("\n[WARNING] in %s : thread[%x,%x] wait TXT_RX / cycle %d\n",
191 __FUNCTION__, process->pid, this->trdid, (uint32_t)hal_get_cycles() );
192
193 // deschedule without blocking
194 sched_yield( "wait TXT_RX ownership" );
195
196 iter++;
197 }
198 else
199 {
200 break;
201 }
202 }
203
204 // move count bytes from device
205 nbytes = devfs_user_move( true, // from device to buffer
206 file_xp,
207 vaddr,
208 count );
209 if( nbytes != count )
210 {
211
212#if DEBUG_SYSCALLS_ERROR
213printk("\n[ERROR] in %s : thread[%x,‰x] cannot read data from file %d\n",
214__FUNCTION__, process->pid, this->trdid, file_id );
215#endif
216 this->errno = EIO;
217 hal_restore_irq( save_sr );
218 return -1;
219 }
220 }
221 else // not FILE and not DEV
222 {
223
224#if DEBUG_SYSCALLS_ERROR
225printk("\n[ERROR] in %s : thread[%x,%x] / illegal inode type %\n",
226__FUNCTION__, vfs_inode_type_str( file_type ) );
227#endif
228 this->errno = EBADFD;
229 hal_restore_irq( save_sr );
230 return -1;
231 }
232
233 // restore IRQs
234 hal_restore_irq( save_sr );
235
236 hal_fence();
237
238#if (DEBUG_SYS_READ || CONFIG_INSTRUMENTATION_SYSCALLS)
239uint64_t tm_end = hal_get_cycles();
240#endif
241
242#if DEBUG_SYS_READ
243if( DEBUG_SYS_READ < tm_end )
244printk("\n[%s] thread[%x,%x] exit / cycle %d\n",
245__FUNCTION__ , process->pid, this->trdid, (uint32_t)tm_end );
246#endif
247
248#if CONFIG_INSTRUMENTATION_SYSCALLS
249hal_atomic_add( &syscalls_cumul_cost[SYS_READ] , tm_end - tm_start );
250hal_atomic_add( &syscalls_occurences[SYS_READ] , 1 );
251#endif
252
253#if (DEBUG_SYS_READ & 1)
254exit_sys_read = (uint32_t)tm_end;
255
256printk("\n***** timing to read one character *****\n"
257" - enter_sys_read = %d / delta %d\n"
258" - enter_devfs_read = %d / delta %d\n"
259" - enter_txt_read = %d / delta %d\n"
260" - enter_chdev_cmd_read = %d / delta %d\n"
261" - enter_chdev_server_read = %d / delta %d\n"
262" - enter_tty_cmd_read = %d / delta %d\n"
263" - enter_tty_isr_read = %d / delta %d\n"
264" - exit_tty_isr_read = %d / delta %d\n"
265" - exit_tty_cmd_read = %d / delta %d\n"
266" - exit_chdev_server_read = %d / delta %d\n"
267" - exit_chdev_cmd_read = %d / delta %d\n"
268" - exit_txt_read = %d / delta %d\n"
269" - exit_devfs_read = %d / delta %d\n"
270" - exit_sys_read = %d / delta %d\n",
271enter_sys_read , 0 ,
272enter_devfs_read , enter_devfs_read - enter_sys_read ,
273enter_txt_read , enter_txt_read - enter_devfs_read ,
274enter_chdev_cmd_read , enter_chdev_cmd_read - enter_txt_read ,
275enter_chdev_server_read , enter_chdev_server_read - enter_chdev_cmd_read ,
276enter_tty_cmd_read , enter_tty_cmd_read - enter_chdev_server_read ,
277enter_tty_isr_read , enter_tty_isr_read - enter_tty_cmd_read ,
278exit_tty_isr_read , exit_tty_isr_read - enter_tty_isr_read ,
279exit_tty_cmd_read , exit_tty_cmd_read - exit_tty_isr_read ,
280exit_chdev_server_read , exit_chdev_server_read - exit_tty_cmd_read ,
281exit_chdev_cmd_read , exit_chdev_cmd_read - exit_chdev_server_read ,
282exit_txt_read , exit_txt_read - exit_chdev_cmd_read ,
283exit_devfs_read , exit_devfs_read - exit_txt_read ,
284exit_sys_read , exit_sys_read - exit_devfs_read );
285#endif
286
287 return nbytes;
288
289} // end sys_read()
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