/* * sys_read.c - Kernel function implementing the "read" system call. * * Author Alain Greiner (2016,2017,2018,2019) * * Copyright (c) UPMC Sorbonne Universites * * This file is part of ALMOS-MKH. * * ALMOS-MKH is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2.0 of the License. * * ALMOS-MKH is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with ALMOS-MKH; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #include #include #include #include #include #include #include #include #include #include #include #include extern uint32_t enter_sys_read; extern uint32_t enter_devfs_read; extern uint32_t enter_txt_read; extern uint32_t enter_chdev_cmd_read; extern uint32_t enter_chdev_server_read; extern uint32_t enter_tty_cmd_read; extern uint32_t enter_tty_isr_read; extern uint32_t exit_tty_isr_read; extern uint32_t exit_tty_cmd_read; extern uint32_t exit_chdev_server_read; extern uint32_t exit_chdev_cmd_read; extern uint32_t exit_txt_read; extern uint32_t exit_devfs_read; extern uint32_t exit_sys_read; ///////////////////////////////// int sys_read( uint32_t file_id, void * vaddr, uint32_t count ) { error_t error; vseg_t * vseg; // required for user space checking xptr_t file_xp; // remote file extended pointer vfs_file_t * file_ptr; // remote file local pointer cxy_t file_cxy; // remote file cluster identifier uint32_t file_type; // file type uint32_t file_offset; // file offset uint32_t file_attr; // file attributes vfs_inode_t * inode_ptr; // local pointer on file inode uint32_t nbytes; // number of bytes actually read reg_t save_sr; // required to enable IRQs during syscall thread_t * this = CURRENT_THREAD; process_t * process = this->process; xptr_t process_owner_xp = process->owner_xp; #if (DEBUG_SYS_READ || CONFIG_INSTRUMENTATION_SYSCALLS) uint64_t tm_start = hal_get_cycles(); #endif #if DEBUG_SYS_READ if( DEBUG_SYS_READ < tm_start ) printk("\n[%s] thread[%x,%x] enter / vaddr %x / count %d / cycle %d\n", __FUNCTION__, process->pid, this->trdid, vaddr, count, (uint32_t)tm_start ); #endif #if (DEBUG_SYS_READ & 1) enter_sys_read = (uint32_t)tm_start; #endif // check file_id argument if( file_id >= CONFIG_PROCESS_FILE_MAX_NR ) { #if DEBUG_SYSCALLS_ERROR printk("\n[ERROR] in %s : thread[%x,%x] illegal file descriptor index %d\n", __FUNCTION__ , process->pid, this->trdid, file_id ); #endif this->errno = EBADFD; return -1; } // check user buffer in user space error = vmm_get_vseg( process , (intptr_t)vaddr , &vseg ); if ( error ) { #if DEBUG_SYSCALLS_ERROR printk("\n[ERROR] in %s : thread[%x,%x] user buffer unmapped %x\n", __FUNCTION__ , process->pid, this->trdid, (intptr_t)vaddr ); #endif this->errno = EINVAL; return -1; } // get extended pointer on remote file descriptor file_xp = process_fd_get_xptr_from_local( process , file_id ); if( file_xp == XPTR_NULL ) { #if DEBUG_SYSCALLS_ERROR printk("\n[ERROR] in %s : thread[%x,%x] undefined fd_id %d\n", __FUNCTION__, process->pid, this->trdid, file_id ); #endif this->errno = EBADFD; return -1; } // get file descriptor cluster and local pointer file_ptr = GET_PTR( file_xp ); file_cxy = GET_CXY( file_xp ); // get inode, file type, offset and attributes inode_ptr = hal_remote_lpt( XPTR( file_cxy , &file_ptr->inode ) ); file_type = hal_remote_l32( XPTR( file_cxy , &file_ptr->type ) ); file_offset = hal_remote_l32( XPTR( file_cxy , &file_ptr->offset ) ); file_attr = hal_remote_l32( XPTR( file_cxy , &file_ptr->attr ) ); // enable IRQs hal_enable_irq( &save_sr ); // action depend on file type: if( file_type == INODE_TYPE_FILE ) // read from file mapper { // check file readable if( (file_attr & FD_ATTR_READ_ENABLE) == 0 ) { #if DEBUG_SYSCALLS_ERROR printk("\n[ERROR] in %s : thread[%x,%x] file %d not readable\n", __FUNCTION__, process->pid, this->trdid, file_id ); #endif hal_restore_irq( save_sr ); this->errno = EBADFD; return -1; } // try to move count bytes from mapper nbytes = vfs_user_move( true, // from mapper to buffer file_xp, vaddr, count ); } else if( file_type == INODE_TYPE_DEV ) // read from TXT device { // get cluster and pointers on TXT_RX chdev xptr_t chdev_xp = chdev_from_file( file_xp ); cxy_t chdev_cxy = GET_CXY( chdev_xp ); chdev_t * chdev_ptr = GET_PTR( chdev_xp ); volatile xptr_t txt_owner_xp; uint32_t iter = 0; while( 1 ) { // extended pointer on TXT owner process txt_owner_xp = hal_remote_l64( XPTR( chdev_cxy , &chdev_ptr->ext.txt.owner_xp ) ); // wait for TXT_RX ownership if ( process_owner_xp != txt_owner_xp ) { if( (iter & 0xFFF) == 0 ) printk("\n[WARNING] in %s : thread[%x,%x] wait TXT_RX / cycle %d\n", __FUNCTION__, process->pid, this->trdid, (uint32_t)hal_get_cycles() ); // deschedule without blocking sched_yield( "wait TXT_RX ownership" ); iter++; } else { break; } } // try to move count bytes from TXT device nbytes = devfs_user_move( true, // from device to buffer file_xp, vaddr, count ); } else // not FILE and not DEV { #if DEBUG_SYSCALLS_ERROR printk("\n[ERROR] in %s : thread[%x,%x] / illegal inode type %\n", __FUNCTION__, vfs_inode_type_str( file_type ) ); #endif this->errno = EBADFD; hal_restore_irq( save_sr ); return -1; } // check error if( nbytes == 0xFFFFFFFF ) { #if DEBUG_SYSCALLS_ERROR printk("\n[ERROR] in %s : thread[%x,‰x] cannot read data from file %d\n", __FUNCTION__, process->pid, this->trdid, file_id ); #endif this->errno = EIO; hal_restore_irq( save_sr ); return -1; } // restore IRQs hal_restore_irq( save_sr ); hal_fence(); #if (DEBUG_SYS_READ || CONFIG_INSTRUMENTATION_SYSCALLS) uint64_t tm_end = hal_get_cycles(); #endif #if DEBUG_SYS_READ if( DEBUG_SYS_READ < tm_end ) printk("\n[%s] thread[%x,%x] exit / cycle %d\n", __FUNCTION__ , process->pid, this->trdid, (uint32_t)tm_end ); #endif #if CONFIG_INSTRUMENTATION_SYSCALLS hal_atomic_add( &syscalls_cumul_cost[SYS_READ] , tm_end - tm_start ); hal_atomic_add( &syscalls_occurences[SYS_READ] , 1 ); #endif #if (DEBUG_SYS_READ & 1) exit_sys_read = (uint32_t)tm_end; printk("\n***** timing to read one character *****\n" " - enter_sys_read = %d / delta %d\n" " - enter_devfs_read = %d / delta %d\n" " - enter_txt_read = %d / delta %d\n" " - enter_chdev_cmd_read = %d / delta %d\n" " - enter_chdev_server_read = %d / delta %d\n" " - enter_tty_cmd_read = %d / delta %d\n" " - enter_tty_isr_read = %d / delta %d\n" " - exit_tty_isr_read = %d / delta %d\n" " - exit_tty_cmd_read = %d / delta %d\n" " - exit_chdev_server_read = %d / delta %d\n" " - exit_chdev_cmd_read = %d / delta %d\n" " - exit_txt_read = %d / delta %d\n" " - exit_devfs_read = %d / delta %d\n" " - exit_sys_read = %d / delta %d\n", enter_sys_read , 0 , enter_devfs_read , enter_devfs_read - enter_sys_read , enter_txt_read , enter_txt_read - enter_devfs_read , enter_chdev_cmd_read , enter_chdev_cmd_read - enter_txt_read , enter_chdev_server_read , enter_chdev_server_read - enter_chdev_cmd_read , enter_tty_cmd_read , enter_tty_cmd_read - enter_chdev_server_read , enter_tty_isr_read , enter_tty_isr_read - enter_tty_cmd_read , exit_tty_isr_read , exit_tty_isr_read - enter_tty_isr_read , exit_tty_cmd_read , exit_tty_cmd_read - exit_tty_isr_read , exit_chdev_server_read , exit_chdev_server_read - exit_tty_cmd_read , exit_chdev_cmd_read , exit_chdev_cmd_read - exit_chdev_server_read , exit_txt_read , exit_txt_read - exit_chdev_cmd_read , exit_devfs_read , exit_devfs_read - exit_txt_read , exit_sys_read , exit_sys_read - exit_devfs_read ); #endif return nbytes; } // end sys_read()