1 /* 2 * Support for initialising programs in new tasks and threads. 3 * 4 * Copyright (C) 2022 Paul Boddie <paul@boddie.org.uk> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as 8 * published by the Free Software Foundation; either version 2 of 9 * the License, or (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, 19 * Boston, MA 02110-1301, USA 20 */ 21 22 #include <l4/sys/err.h> 23 #include <l4/sys/scheduler.h> 24 25 #include <exec/process.h> 26 #include <ipc/cap_alloc.h> 27 #include <ipc/map.h> 28 #include <mem/memory_utils.h> 29 30 31 32 /* Obtain a flexpage defining the UTCB area location and size in a new task. */ 33 34 static l4_fpage_t get_utcb_fpage(unsigned int page, unsigned int pages) 35 { 36 /* UTCB location and size. */ 37 38 int utcb_log2size = page_order(pages * Default_max_threads * L4_UTCB_OFFSET); 39 40 /* Round up to at least one page. */ 41 42 if (utcb_log2size < L4_PAGESHIFT) 43 utcb_log2size = L4_PAGESHIFT; 44 45 return l4_fpage(Utcb_area_start + page * (1UL << utcb_log2size), utcb_log2size, 0); 46 } 47 48 49 50 /* Initialise a new process, this being an abstraction for a new task with some 51 threads. */ 52 53 Process::Process(int reserved_threads) 54 { 55 _thread_number = 0; 56 57 /* Populate the common initial environment for the threads. */ 58 59 _env.factory = L4_BASE_FACTORY_CAP; 60 _env.log = L4_BASE_LOG_CAP; 61 _env.scheduler = L4_BASE_SCHEDULER_CAP; 62 _env.mem_alloc = L4_EXEC_MA_CAP; 63 64 /* Capability details that are updated for each thread. */ 65 66 _env.main_thread = L4_BASE_THREAD_CAP; 67 _env.rm = L4_EXEC_RM_CAP; 68 _env.first_free_cap = L4_EXEC_FIRST_FREE_CAP_INDEX; 69 70 /* Populate auxiliary information. */ 71 72 _aux.kip_ds = L4_EXEC_KIP_CAP; 73 _aux.dbg_lvl = 0; 74 _aux.ldr_flags = 0; 75 } 76 77 /* Capability index allocation. */ 78 79 l4_cap_idx_t Process::allocate_cap() 80 { 81 return (_env.first_free_cap++ << L4_CAP_SHIFT); 82 } 83 84 /* Task and thread initialisation. */ 85 86 long Process::create_task() 87 { 88 _task = ipc_cap_alloc(); 89 90 if (l4_is_invalid_cap(_task)) 91 return -L4_ENOMEM; 92 93 return l4_error(l4_factory_create_task(l4re_env()->factory, _task, get_utcb_fpage(0, 2))); 94 } 95 96 long Process::create_thread(l4_cap_idx_t *thread) 97 { 98 *thread = ipc_cap_alloc(); 99 100 if (l4_is_invalid_cap(*thread)) 101 return -L4_ENOMEM; 102 103 return l4_error(l4_factory_create_thread(l4re_env()->factory, *thread)); 104 } 105 106 /* Configure the task environment. */ 107 108 long Process::configure_task() 109 { 110 long err = create_task(); 111 112 if (err) 113 return err; 114 115 /* Map the KIP into the task. */ 116 117 l4_addr_t kip_start = (l4_addr_t) l4re_kip(); 118 119 err = l4_error(l4_task_map(_task, L4RE_THIS_TASK_CAP, 120 l4_fpage(kip_start, L4_PAGESHIFT, L4_FPAGE_RX), 121 kip_start)); 122 123 if (err) 124 return err; 125 126 /* Define capability mappings for the new task. */ 127 128 struct ipc_mapped_cap mapped_caps[] = { 129 {L4_BASE_TASK_CAP, _task, L4_CAP_FPAGE_RWS, 0}, 130 {_env.factory, l4re_env()->factory, L4_CAP_FPAGE_RWS, 0}, 131 {_env.log, l4re_env()->log, L4_CAP_FPAGE_RWS, 0}, 132 {_env.scheduler, l4re_env()->scheduler, L4_CAP_FPAGE_RWS, 0}, 133 {_env.mem_alloc, l4re_env()->mem_alloc, L4_CAP_FPAGE_RWS, 0}, 134 {0, L4_INVALID_CAP, 0, 0}, 135 }; 136 137 return map_capabilities(mapped_caps, false); 138 } 139 140 /* Configure the thread environment. */ 141 142 long Process::configure_thread(l4_cap_idx_t server, l4_cap_idx_t mapped_cap) 143 { 144 /* Employ a distinct region mapper for each thread's environment, this acting 145 as pager. */ 146 147 if (l4_is_valid_cap(mapped_cap)) 148 { 149 _env.rm = mapped_cap; 150 return L4_EOK; 151 } 152 else 153 { 154 _env.rm = allocate_cap(); 155 return ipc_map_capability(_task, (struct ipc_mapped_cap) {_env.rm, server, L4_CAP_FPAGE_RWS, 0}); 156 } 157 } 158 159 /* Map capabilities into the task, counting them if indicated. */ 160 161 long Process::map_capabilities(struct ipc_mapped_cap mapped_caps[], 162 bool to_count) 163 { 164 unsigned int num_mapped_caps; 165 long err = ipc_map_capabilities(_task, mapped_caps, to_count ? &num_mapped_caps : NULL); 166 167 if (to_count) 168 _env.first_free_cap += num_mapped_caps; 169 170 return err; 171 } 172 173 /* Create, initialise and start a thread. */ 174 175 long Process::thread_start(l4_addr_t program_start, Stack &st) 176 { 177 l4_cap_idx_t thread; 178 long err; 179 180 err = create_thread(&thread); 181 182 if (err) 183 return err; 184 185 /* Obtain UTCB area details for the thread. */ 186 187 l4_fpage_t utcb_fpage = get_utcb_fpage(_thread_number, 1); 188 189 _env.utcb_area = utcb_fpage; 190 _env.first_free_utcb = l4_fpage_memaddr(utcb_fpage); 191 192 /* Initialise the thread with pager, UTCB and task details. */ 193 194 l4_thread_control_start(); 195 l4_thread_control_pager(_env.rm); 196 l4_thread_control_exc_handler(_env.rm); 197 l4_thread_control_bind((l4_utcb_t *) l4_fpage_memaddr(_env.utcb_area), _task); 198 199 err = l4_error(l4_thread_control_commit(thread)); 200 201 if (err) 202 { 203 ipc_cap_free(thread); 204 return err; 205 } 206 207 /* Map the thread capability to the task using a distinct capability index. */ 208 209 _env.main_thread = allocate_cap(); 210 211 ipc_map_capability(_task, (struct ipc_mapped_cap) {_env.main_thread, thread, L4_CAP_FPAGE_RWS, 0}); 212 213 /* Populate the initial environment in the thread. */ 214 215 st.set_l4re_aux(&_aux); 216 st.set_l4re_env(&_env); 217 218 /* Reserve some extra space for capabilities used by this thread. 219 NOTE: Surely the capability allocator should be able to avoid conflicts, 220 but concurrency issues have been observed before, leading to various 221 measures in libipc. */ 222 223 _env.first_free_cap += 0x20; 224 225 /* Set the start details. */ 226 227 err = l4_error(l4_thread_ex_regs(thread, program_start, st.start_address(), 0)); 228 229 if (err) 230 return err; 231 232 /* Select a new thread. */ 233 234 _thread_number++; 235 236 /* Start the thread. */ 237 238 l4_sched_param_t sp = l4_sched_param(L4RE_MAIN_THREAD_PRIO); 239 240 return l4_error(l4_scheduler_run_thread(l4re_env()->scheduler, thread, &sp)); 241 } 242 243 /* vim: tabstop=2 expandtab shiftwidth=2 244 */