source: trunk/kernel/syscalls/sys_read.c @ 569

Last change on this file since 569 was 566, checked in by alain, 6 years ago

Complete restructuration of kernel locks.

File size: 8.8 KB
RevLine 
[1]1/*
[23]2 * sys_read.c - read bytes from a file
[1]3 *
[440]4 * Author     Alain Greiner (2016,2017,2018)
[1]5 *
[23]6 * Copyright (c) UPMC Sorbonne Universites
[1]7 *
[23]8 * This file is part of ALMOS-MKH.
9 *
10 * ALMOS-MKH is free software; you can redistribute it and/or modify it
[1]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 *
[23]14 * ALMOS-MKH is distributed in the hope that it will be useful, but
[1]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
[23]20 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
[1]21 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
[23]24#include <kernel_config.h>
[457]25#include <hal_kernel_types.h>
[23]26#include <hal_uspace.h>
[409]27#include <hal_irqmask.h>
[23]28#include <hal_special.h>
[1]29#include <errno.h>
[23]30#include <vfs.h>
31#include <vmm.h>
[1]32#include <thread.h>
[23]33#include <printk.h>
34#include <process.h>
[1]35
[506]36
[407]37extern uint32_t enter_sys_read;
[436]38extern uint32_t enter_devfs_read;
[407]39extern uint32_t enter_txt_read;
[436]40extern uint32_t enter_chdev_cmd_read;
41extern uint32_t enter_chdev_server_read;
42extern uint32_t enter_tty_cmd_read;
43extern uint32_t enter_tty_isr_read;
44extern uint32_t exit_tty_isr_read;
45extern uint32_t exit_tty_cmd_read;
46extern uint32_t exit_chdev_server_read;
47extern uint32_t exit_chdev_cmd_read;
[407]48extern uint32_t exit_txt_read;
[436]49extern uint32_t exit_devfs_read;
[407]50extern uint32_t exit_sys_read;
51
52
[23]53/////////////////////////////////
54int sys_read( uint32_t   file_id,
[407]55              void     * vaddr,
[23]56              uint32_t   count )
[1]57{
[23]58    error_t      error;
[440]59    vseg_t     * vseg;        // required for user space checking
[23]60        xptr_t       file_xp;     // remote file extended pointer
[407]61    uint32_t     nbytes;      // number of bytes actually read
[408]62    reg_t        save_sr;     // required to enable IRQs during syscall
[407]63
[446]64        thread_t  *  this             = CURRENT_THREAD;
65        process_t *  process          = this->process;
66    xptr_t       process_owner_xp = process->owner_xp;
[23]67 
[566]68#if (DEBUG_SYS_READ || CONFIG_INSTRUMENTATION_SYSCALLS)
69uint64_t     tm_start = hal_get_cycles();
70#endif
71
[438]72#if DEBUG_SYS_READ
73if( DEBUG_SYS_READ < tm_start )
[459]74printk("\n[DBG] %s : thread %x in process %x enter / vaddr %x / count %d / cycle %d\n",
75__FUNCTION__, this->trdid, process->pid, vaddr, count, (uint32_t)tm_start );
[433]76#endif
77
[438]78#if (DEBUG_SYS_READ & 1)
[436]79enter_sys_read = (uint32_t)tm_start;
80#endif
81
[23]82    // check file_id argument
83        if( file_id >= CONFIG_PROCESS_FILE_MAX_NR )
[1]84        {
[435]85
[438]86#if DEBUG_SYSCALLS_ERROR
[435]87printk("\n[ERROR] in %s : illegal file descriptor index = %d\n", __FUNCTION__ , file_id );
88#endif
[23]89                this->errno = EBADFD;
[1]90                return -1;
91        }
92
[23]93    // check user buffer in user space
[440]94    error = vmm_get_vseg( process , (intptr_t)vaddr , &vseg );
[23]95
96    if ( error )
97    {
[435]98
[438]99#if DEBUG_SYSCALLS_ERROR
[440]100printk("\n[ERROR] in %s : user buffer unmapped %x / thread %x / process %x\n",
101__FUNCTION__ , (intptr_t)vaddr, this->trdid, process->pid );
102vmm_display( process , false );
[435]103#endif
[23]104                this->errno = EINVAL;
105                return -1;
106    }
107
[408]108    // enable IRQs
[421]109    hal_enable_irq( &save_sr );
[408]110
[23]111    // get extended pointer on remote file descriptor
112    file_xp = process_fd_get_xptr( process , file_id );
113
114    if( file_xp == XPTR_NULL )
115    {
[435]116
[438]117#if DEBUG_SYSCALLS_ERROR
[435]118printk("\n[ERROR] in %s : undefined fd_id %d in process %x\n",
119__FUNCTION__ , file_id , process->pid );
120#endif
[23]121        this->errno = EBADFD;
122        return -1;
123    }
124
125    // get file descriptor cluster and local pointer
[436]126    vfs_file_t * file_ptr = GET_PTR( file_xp );
[23]127    cxy_t        file_cxy = GET_CXY( file_xp );
128
129    // check file readable
[566]130    uint32_t attr = hal_remote_l32( XPTR( file_cxy , &file_ptr->attr ) );
[23]131    if( (attr & FD_ATTR_READ_ENABLE) == 0 )
[1]132        {
[435]133
[438]134#if DEBUG_SYSCALLS_ERROR
[435]135printk("\n[ERROR] in %s : file %d not readable in process %x\n",
136__FUNCTION__ , file_id , process->pid );
137#endif
[23]138                this->errno = EBADFD;
[1]139                return -1;
140        }
[313]141   
[407]142    // get file type
[566]143    vfs_inode_type_t type = hal_remote_l32( XPTR( file_cxy , &file_ptr->type ) );
[313]144
[407]145    // action depend on file type
[421]146    if( type == INODE_TYPE_FILE )      // check file readable & read from mapper
[23]147    {
[421]148        // check file readable
[566]149        uint32_t attr = hal_remote_l32( XPTR( file_cxy , &file_ptr->attr ) );
[443]150
[421]151        if( (attr & FD_ATTR_READ_ENABLE) == 0 )
152            {
[435]153
[438]154#if DEBUG_SYSCALLS_ERROR
[435]155printk("\n[ERROR] in %s : file %d not readable in process %x\n",
156__FUNCTION__ , file_id , process->pid );
157#endif
[421]158                    this->errno = EBADFD;
159                    return -1;
160            }
161
162        // move count bytes from mapper
[407]163        nbytes = vfs_user_move( true,               // from mapper to buffer
164                                file_xp,
165                                vaddr, 
166                                count );
167    }
[446]168    else if( type == INODE_TYPE_DEV )  // check ownership & read from device
[407]169    {
[436]170        // get cluster and pointers on TXT_RX chdev
171        xptr_t    chdev_xp  = chdev_from_file( file_xp );
172        cxy_t     chdev_cxy = GET_CXY( chdev_xp );
173        chdev_t * chdev_ptr = GET_PTR( chdev_xp );
174
[446]175        volatile xptr_t    txt_owner_xp;   
176        uint32_t           iter = 0;
[436]177
178        while( 1 )
179        {
[446]180            // extended pointer on TXT owner process
[566]181            txt_owner_xp  = hal_remote_l64( XPTR( chdev_cxy , &chdev_ptr->ext.txt.owner_xp ) );
[436]182
183            // check TXT_RX ownership
[446]184            if ( process_owner_xp != txt_owner_xp )
[436]185            {
[446]186                if( (iter & 0xFFF) == 0 )
187                printk("\n[WARNING] in %s : thread %x in process %x wait TXT_RX / cycle %d\n",
188                __FUNCTION__, this->trdid, process->pid, (uint32_t)hal_get_cycles() );
189
[436]190                // deschedule without blocking
[446]191                sched_yield( "wait TXT_RX ownership" );
192
193                iter++;
[436]194            }
195            else
196            {
197                break;
198            }
199        }
200
[421]201        // move count bytes from device
[407]202        nbytes = devfs_user_move( true,             // from device to buffer
203                                  file_xp,
204                                  vaddr,
205                                  count );
[421]206
[407]207    }
208    else
209    {
210        nbytes = 0;
[492]211        assert( false , "file type %d non supported yet\n", type );
[407]212    }
213
214    if( nbytes != count )
215    {
[435]216
[438]217#if DEBUG_SYSCALLS_ERROR
[435]218printk("\n[ERROR] in %s cannot read data from file %d in process %x\n",
219__FUNCTION__ , file_id , process->pid );
220#endif
[313]221        this->errno = error;
222        return -1;
[23]223    }
224
[408]225    // restore IRQs
[421]226    hal_restore_irq( save_sr );
[408]227
[124]228    hal_fence();
[23]229
[566]230#if (DEBUG_SYS_READ || CONFIG_INSTRUMENTATION_SYSCALLS)
231uint64_t     tm_end = hal_get_cycles();
232#endif
233
[438]234#if DEBUG_SYS_READ
235if( DEBUG_SYS_READ < tm_end )
[566]236printk("\n[DBG] %s : thread %x in process %x exit / cycle %d\n",
237__FUNCTION__ , this->trdid, process->pid, (uint32_t)tm_end );
[409]238#endif
[23]239
[566]240#if CONFIG_INSTRUMENTATION_SYSCALLS
241hal_atomic_add( &syscalls_cumul_cost[SYS_READ] , tm_end - tm_start );
242hal_atomic_add( &syscalls_occurences[SYS_READ] , 1 );
243#endif
244
[438]245#if (DEBUG_SYS_READ & 1)
[418]246exit_sys_read = (uint32_t)tm_end;
[407]247
[443]248printk("\n***** timing to read one character *****\n"
[435]249" - enter_sys_read          = %d / delta %d\n"
250" - enter_devfs_read        = %d / delta %d\n"
251" - enter_txt_read          = %d / delta %d\n"
252" - enter_chdev_cmd_read    = %d / delta %d\n"
253" - enter_chdev_server_read = %d / delta %d\n"
254" - enter_tty_cmd_read      = %d / delta %d\n"
255" - enter_tty_isr_read      = %d / delta %d\n"
256" - exit_tty_isr_read       = %d / delta %d\n"
257" - exit_tty_cmd_read       = %d / delta %d\n"
258" - exit_chdev_server_read  = %d / delta %d\n"
259" - exit_chdev_cmd_read     = %d / delta %d\n"
260" - exit_txt_read           = %d / delta %d\n"
261" - exit_devfs_read         = %d / delta %d\n"
262" - exit_sys_read           = %d / delta %d\n",
263enter_sys_read          , 0 ,
264enter_devfs_read        , enter_devfs_read        - enter_sys_read          ,
265enter_txt_read          , enter_txt_read          - enter_devfs_read        ,
266enter_chdev_cmd_read    , enter_chdev_cmd_read    - enter_txt_read          ,
267enter_chdev_server_read , enter_chdev_server_read - enter_chdev_cmd_read    ,
268enter_tty_cmd_read      , enter_tty_cmd_read      - enter_chdev_server_read ,
269enter_tty_isr_read      , enter_tty_isr_read      - enter_tty_cmd_read      ,
270exit_tty_isr_read       , exit_tty_isr_read       - enter_tty_isr_read      ,
271exit_tty_cmd_read       , exit_tty_cmd_read       - exit_tty_isr_read       ,
272exit_chdev_server_read  , exit_chdev_server_read  - exit_tty_cmd_read       ,
273exit_chdev_cmd_read     , exit_chdev_cmd_read     - exit_chdev_server_read  ,
274exit_txt_read           , exit_txt_read           - exit_chdev_cmd_read     ,
275exit_devfs_read         , exit_devfs_read         - exit_txt_read           ,
276exit_sys_read           , exit_sys_read           - exit_devfs_read         );
[407]277#endif
278 
279        return nbytes;
280
[23]281}  // end sys_read()
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