| 1 | /*
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| 2 | * sys_read.c - Kernel function implementing the "read" system call.
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| 3 | *
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| 4 | * Author Alain Greiner (2016,2017,2018,2019)
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| 5 | *
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| 6 | * Copyright (c) UPMC Sorbonne Universites
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| 7 | *
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| 8 | * This file is part of ALMOS-MKH.
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| 9 | *
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| 10 | * ALMOS-MKH is free software; you can redistribute it and/or modify it
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| 11 | * under the terms of the GNU General Public License as published by
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| 12 | * the Free Software Foundation; version 2.0 of the License.
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| 13 | *
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| 14 | * ALMOS-MKH is distributed in the hope that it will be useful, but
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| 15 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 17 | * General Public License for more details.
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| 18 | *
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| 19 | * You should have received a copy of the GNU General Public License
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| 20 | * along with ALMOS-MKH; if not, write to the Free Software Foundation,
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| 21 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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| 22 | */
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| 23 |
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| 24 | #include <kernel_config.h>
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| 25 | #include <hal_kernel_types.h>
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| 26 | #include <hal_vmm.h>
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| 27 | #include <hal_uspace.h>
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| 28 | #include <hal_irqmask.h>
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| 29 | #include <hal_special.h>
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| 30 | #include <errno.h>
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| 31 | #include <vfs.h>
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| 32 | #include <vmm.h>
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| 33 | #include <thread.h>
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| 34 | #include <printk.h>
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| 35 | #include <process.h>
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| 36 |
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| 37 |
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| 38 | extern uint32_t enter_sys_read;
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| 39 | extern uint32_t enter_devfs_read;
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| 40 | extern uint32_t enter_txt_read;
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| 41 | extern uint32_t enter_chdev_cmd_read;
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| 42 | extern uint32_t enter_chdev_server_read;
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| 43 | extern uint32_t enter_tty_cmd_read;
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| 44 | extern uint32_t enter_tty_isr_read;
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| 45 | extern uint32_t exit_tty_isr_read;
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| 46 | extern uint32_t exit_tty_cmd_read;
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| 47 | extern uint32_t exit_chdev_server_read;
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| 48 | extern uint32_t exit_chdev_cmd_read;
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| 49 | extern uint32_t exit_txt_read;
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| 50 | extern uint32_t exit_devfs_read;
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| 51 | extern uint32_t exit_sys_read;
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| 52 |
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| 53 |
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| 54 | /////////////////////////////////
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| 55 | int sys_read( uint32_t file_id,
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| 56 | void * vaddr,
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| 57 | uint32_t count )
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| 58 | {
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| 59 | error_t error;
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| 60 | vseg_t * vseg; // required for user space checking
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| 61 | xptr_t file_xp; // remote file extended pointer
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| 62 | vfs_file_t * file_ptr; // remote file local pointer
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| 63 | cxy_t file_cxy; // remote file cluster identifier
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| 64 | uint32_t file_type; // file type
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| 65 | uint32_t file_offset; // file offset
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| 66 | uint32_t file_attr; // file attributes
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| 67 | vfs_inode_t * inode_ptr; // local pointer on file inode
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| 68 | uint32_t nbytes; // number of bytes actually read
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| 69 | reg_t save_sr; // required to enable IRQs during syscall
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| 70 |
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| 71 | thread_t * this = CURRENT_THREAD;
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| 72 | process_t * process = this->process;
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| 73 | xptr_t process_owner_xp = process->owner_xp;
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| 74 |
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| 75 | #if (DEBUG_SYS_READ || CONFIG_INSTRUMENTATION_SYSCALLS)
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| 76 | uint64_t tm_start = hal_get_cycles();
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| 77 | #endif
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| 78 |
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| 79 | #if DEBUG_SYS_READ
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| 80 | if( DEBUG_SYS_READ < tm_start )
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| 81 | printk("\n[%s] thread[%x,%x] enter / vaddr %x / count %d / cycle %d\n",
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| 82 | __FUNCTION__, process->pid, this->trdid, vaddr, count, (uint32_t)tm_start );
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| 83 | #endif
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| 84 |
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| 85 | #if (DEBUG_SYS_READ & 1)
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| 86 | enter_sys_read = (uint32_t)tm_start;
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| 87 | #endif
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| 88 |
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| 89 | // check file_id argument
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| 90 | if( file_id >= CONFIG_PROCESS_FILE_MAX_NR )
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| 91 | {
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| 92 |
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| 93 | #if DEBUG_SYSCALLS_ERROR
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| 94 | printk("\n[ERROR] in %s : thread[%x,%x] illegal file descriptor index %d\n",
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| 95 | __FUNCTION__ , process->pid, this->trdid, file_id );
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| 96 | #endif
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| 97 | this->errno = EBADFD;
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| 98 | return -1;
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| 99 | }
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| 100 |
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| 101 | // check user buffer in user space
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| 102 | error = vmm_get_vseg( process , (intptr_t)vaddr , &vseg );
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| 103 |
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| 104 | if ( error )
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| 105 | {
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| 106 |
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| 107 | #if DEBUG_SYSCALLS_ERROR
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| 108 | printk("\n[ERROR] in %s : thread[%x,%x] user buffer unmapped %x\n",
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| 109 | __FUNCTION__ , process->pid, this->trdid, (intptr_t)vaddr );
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| 110 | #endif
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| 111 | this->errno = EINVAL;
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| 112 | return -1;
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| 113 | }
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| 114 |
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| 115 | // get extended pointer on remote file descriptor
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| 116 | file_xp = process_fd_get_xptr_from_local( process , file_id );
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| 117 |
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| 118 | if( file_xp == XPTR_NULL )
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| 119 | {
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| 120 |
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| 121 | #if DEBUG_SYSCALLS_ERROR
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| 122 | printk("\n[ERROR] in %s : thread[%x,%x] undefined fd_id %d\n",
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| 123 | __FUNCTION__, process->pid, this->trdid, file_id );
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| 124 | #endif
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| 125 | this->errno = EBADFD;
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| 126 | return -1;
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| 127 | }
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| 128 |
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| 129 | // get file descriptor cluster and local pointer
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| 130 | file_ptr = GET_PTR( file_xp );
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| 131 | file_cxy = GET_CXY( file_xp );
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| 132 |
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| 133 | // get inode, file type, offset and attributes
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| 134 | inode_ptr = hal_remote_lpt( XPTR( file_cxy , &file_ptr->inode ) );
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| 135 | file_type = hal_remote_l32( XPTR( file_cxy , &file_ptr->type ) );
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| 136 | file_offset = hal_remote_l32( XPTR( file_cxy , &file_ptr->offset ) );
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| 137 | file_attr = hal_remote_l32( XPTR( file_cxy , &file_ptr->attr ) );
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| 138 |
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| 139 | // enable IRQs
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| 140 | hal_enable_irq( &save_sr );
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| 141 |
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| 142 | // action depend on file type:
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| 143 |
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| 144 | if( file_type == INODE_TYPE_FILE ) // read from file mapper
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| 145 | {
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| 146 | // check file readable
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| 147 | if( (file_attr & FD_ATTR_READ_ENABLE) == 0 )
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| 148 | {
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| 149 |
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| 150 | #if DEBUG_SYSCALLS_ERROR
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| 151 | printk("\n[ERROR] in %s : thread[%x,%x] file %d not readable\n",
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| 152 | __FUNCTION__, process->pid, this->trdid, file_id );
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| 153 | #endif
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| 154 | hal_restore_irq( save_sr );
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| 155 | this->errno = EBADFD;
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| 156 | return -1;
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| 157 | }
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| 158 |
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| 159 | // try to move count bytes from mapper
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| 160 | nbytes = vfs_user_move( true, // from mapper to buffer
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| 161 | file_xp,
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| 162 | vaddr,
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| 163 | count );
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| 164 | }
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| 165 | else if( file_type == INODE_TYPE_DEV ) // read from TXT device
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| 166 | {
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| 167 | // get cluster and pointers on TXT_RX chdev
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| 168 | xptr_t chdev_xp = chdev_from_file( file_xp );
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| 169 | cxy_t chdev_cxy = GET_CXY( chdev_xp );
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| 170 | chdev_t * chdev_ptr = GET_PTR( chdev_xp );
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| 171 |
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| 172 | volatile xptr_t txt_owner_xp;
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| 173 | uint32_t iter = 0;
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| 174 |
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| 175 | while( 1 )
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| 176 | {
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| 177 | // extended pointer on TXT owner process
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| 178 | txt_owner_xp = hal_remote_l64( XPTR( chdev_cxy , &chdev_ptr->ext.txt.owner_xp ) );
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| 179 |
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| 180 | // wait for TXT_RX ownership
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| 181 | if ( process_owner_xp != txt_owner_xp )
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| 182 | {
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| 183 | if( (iter & 0xFFF) == 0 )
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| 184 | printk("\n[WARNING] in %s : thread[%x,%x] wait TXT_RX / cycle %d\n",
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| 185 | __FUNCTION__, process->pid, this->trdid, (uint32_t)hal_get_cycles() );
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| 186 |
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| 187 | // deschedule without blocking
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| 188 | sched_yield( "wait TXT_RX ownership" );
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| 189 |
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| 190 | iter++;
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| 191 | }
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| 192 | else
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| 193 | {
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| 194 | break;
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| 195 | }
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| 196 | }
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| 197 |
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| 198 | // try to move count bytes from TXT device
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| 199 | nbytes = devfs_user_move( true, // from device to buffer
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| 200 | file_xp,
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| 201 | vaddr,
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| 202 | count );
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| 203 | }
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| 204 | else // not FILE and not DEV
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| 205 | {
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| 206 |
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| 207 | #if DEBUG_SYSCALLS_ERROR
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| 208 | printk("\n[ERROR] in %s : thread[%x,%x] / illegal inode type %\n",
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| 209 | __FUNCTION__, vfs_inode_type_str( file_type ) );
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| 210 | #endif
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| 211 | this->errno = EBADFD;
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| 212 | hal_restore_irq( save_sr );
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| 213 | return -1;
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| 214 | }
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| 215 |
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| 216 | // check error
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| 217 | if( nbytes == 0xFFFFFFFF )
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| 218 | {
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| 219 |
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| 220 | #if DEBUG_SYSCALLS_ERROR
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| 221 | printk("\n[ERROR] in %s : thread[%x,‰x] cannot read data from file %d\n",
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| 222 | __FUNCTION__, process->pid, this->trdid, file_id );
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| 223 | #endif
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| 224 | this->errno = EIO;
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| 225 | hal_restore_irq( save_sr );
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| 226 | return -1;
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| 227 | }
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| 228 |
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| 229 | // restore IRQs
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| 230 | hal_restore_irq( save_sr );
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| 231 |
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| 232 | hal_fence();
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| 233 |
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| 234 | #if (DEBUG_SYS_READ || CONFIG_INSTRUMENTATION_SYSCALLS)
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| 235 | uint64_t tm_end = hal_get_cycles();
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| 236 | #endif
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| 237 |
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| 238 | #if DEBUG_SYS_READ
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| 239 | if( DEBUG_SYS_READ < tm_end )
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| 240 | printk("\n[%s] thread[%x,%x] exit / cycle %d\n",
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| 241 | __FUNCTION__ , process->pid, this->trdid, (uint32_t)tm_end );
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| 242 | #endif
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| 243 |
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| 244 | #if CONFIG_INSTRUMENTATION_SYSCALLS
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| 245 | hal_atomic_add( &syscalls_cumul_cost[SYS_READ] , tm_end - tm_start );
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| 246 | hal_atomic_add( &syscalls_occurences[SYS_READ] , 1 );
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| 247 | #endif
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| 248 |
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| 249 | #if (DEBUG_SYS_READ & 1)
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| 250 | exit_sys_read = (uint32_t)tm_end;
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| 251 |
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| 252 | printk("\n***** timing to read one character *****\n"
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| 253 | " - enter_sys_read = %d / delta %d\n"
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| 254 | " - enter_devfs_read = %d / delta %d\n"
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| 255 | " - enter_txt_read = %d / delta %d\n"
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| 256 | " - enter_chdev_cmd_read = %d / delta %d\n"
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| 257 | " - enter_chdev_server_read = %d / delta %d\n"
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| 258 | " - enter_tty_cmd_read = %d / delta %d\n"
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| 259 | " - enter_tty_isr_read = %d / delta %d\n"
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| 260 | " - exit_tty_isr_read = %d / delta %d\n"
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| 261 | " - exit_tty_cmd_read = %d / delta %d\n"
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| 262 | " - exit_chdev_server_read = %d / delta %d\n"
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| 263 | " - exit_chdev_cmd_read = %d / delta %d\n"
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| 264 | " - exit_txt_read = %d / delta %d\n"
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| 265 | " - exit_devfs_read = %d / delta %d\n"
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| 266 | " - exit_sys_read = %d / delta %d\n",
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| 267 | enter_sys_read , 0 ,
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| 268 | enter_devfs_read , enter_devfs_read - enter_sys_read ,
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| 269 | enter_txt_read , enter_txt_read - enter_devfs_read ,
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| 270 | enter_chdev_cmd_read , enter_chdev_cmd_read - enter_txt_read ,
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| 271 | enter_chdev_server_read , enter_chdev_server_read - enter_chdev_cmd_read ,
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| 272 | enter_tty_cmd_read , enter_tty_cmd_read - enter_chdev_server_read ,
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| 273 | enter_tty_isr_read , enter_tty_isr_read - enter_tty_cmd_read ,
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| 274 | exit_tty_isr_read , exit_tty_isr_read - enter_tty_isr_read ,
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| 275 | exit_tty_cmd_read , exit_tty_cmd_read - exit_tty_isr_read ,
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| 276 | exit_chdev_server_read , exit_chdev_server_read - exit_tty_cmd_read ,
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| 277 | exit_chdev_cmd_read , exit_chdev_cmd_read - exit_chdev_server_read ,
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| 278 | exit_txt_read , exit_txt_read - exit_chdev_cmd_read ,
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| 279 | exit_devfs_read , exit_devfs_read - exit_txt_read ,
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| 280 | exit_sys_read , exit_sys_read - exit_devfs_read );
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| 281 | #endif
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| 282 |
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| 283 | return nbytes;
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| 284 |
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| 285 | } // end sys_read()
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