1 /* 2 * Support for initialising programs in new tasks and threads. 3 * 4 * Copyright (C) 2022, 2023 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(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 utcb_log2size = page_order(pages * (1UL << utcb_log2size)); 46 47 return l4_fpage(Utcb_area_start + page * (1UL << utcb_log2size), utcb_log2size, 0); 48 } 49 50 51 52 /* Initialise a new process, this being an abstraction for a new task with some 53 threads. */ 54 55 Process::Process() 56 { 57 reset(); 58 } 59 60 void Process::reset() 61 { 62 _thread_number = 0; 63 64 /* Populate the common initial environment for the threads. */ 65 66 _env.factory = L4_BASE_FACTORY_CAP; 67 _env.log = L4_BASE_LOG_CAP; 68 _env.scheduler = L4_BASE_SCHEDULER_CAP; 69 _env.mem_alloc = L4_EXEC_MA_CAP; 70 _env.parent = L4_EXEC_PARENT_CAP; 71 72 /* Capability details that are updated for each thread. Note that the region 73 mapper is redefined, but it would traditionally employ the given index. */ 74 75 _env.main_thread = L4_BASE_THREAD_CAP; 76 _env.rm = L4_EXEC_RM_CAP; 77 _env.first_free_cap = L4_EXEC_FIRST_FREE_CAP_INDEX; 78 79 /* Populate auxiliary information. */ 80 81 _aux.kip_ds = L4_EXEC_KIP_CAP; 82 _aux.dbg_lvl = 0; 83 _aux.ldr_flags = 0; 84 } 85 86 /* Capability index allocation. */ 87 88 l4_cap_idx_t Process::allocate_cap() 89 { 90 return (_env.first_free_cap++ << L4_CAP_SHIFT); 91 } 92 93 /* Task and thread initialisation. */ 94 95 long Process::create_task(unsigned int threads) 96 { 97 /* Reset the process if it has already been used. */ 98 99 if (_thread_number) 100 reset(); 101 102 _task = ipc_cap_alloc(); 103 104 if (l4_is_invalid_cap(_task)) 105 return -L4_ENOMEM; 106 107 return l4_error(l4_factory_create_task(l4re_env()->factory, _task, get_utcb_fpage(0, threads))); 108 } 109 110 long Process::create_thread(l4_cap_idx_t *thread) 111 { 112 *thread = ipc_cap_alloc(); 113 114 if (l4_is_invalid_cap(*thread)) 115 return -L4_ENOMEM; 116 117 return l4_error(l4_factory_create_thread(l4re_env()->factory, *thread)); 118 } 119 120 /* Configure the task environment. */ 121 122 long Process::configure_task(l4_cap_idx_t *task, l4_cap_idx_t *mapped_task, unsigned int threads) 123 { 124 long err = create_task(threads); 125 126 if (err) 127 return err; 128 129 /* Map the KIP into the task. */ 130 131 l4_addr_t kip_start = (l4_addr_t) l4re_kip(); 132 133 err = l4_error(l4_task_map(_task, L4RE_THIS_TASK_CAP, 134 l4_fpage(kip_start, L4_PAGESHIFT, L4_FPAGE_RX), 135 kip_start)); 136 137 if (err) 138 return err; 139 140 /* Define capability mappings for the new task. */ 141 142 struct ipc_mapped_cap mapped_caps[] = { 143 {L4_BASE_TASK_CAP, _task, L4_CAP_FPAGE_RWS, 0}, 144 {_env.factory, l4re_env()->factory, L4_CAP_FPAGE_RWS, 0}, 145 {_env.log, l4re_env()->log, L4_CAP_FPAGE_RWS, 0}, 146 {_env.scheduler, l4re_env()->scheduler, L4_CAP_FPAGE_RWS, 0}, 147 {_env.mem_alloc, l4re_env()->mem_alloc, L4_CAP_FPAGE_RWS, 0}, 148 {0, L4_INVALID_CAP, 0, 0}, 149 }; 150 151 /* Return the capability details for the task. */ 152 153 *task = _task; 154 *mapped_task = L4_BASE_TASK_CAP; 155 156 return map_capabilities(mapped_caps, false); 157 } 158 159 /* Configure the thread environment, employing the given capability for the 160 region mapper, returning its capability details in the new task. */ 161 162 long Process::configure_thread(l4_cap_idx_t rm, l4_cap_idx_t *mapped_rm) 163 { 164 /* Employ a distinct region mapper for each thread's environment, this acting 165 as pager. */ 166 167 if ((mapped_rm != NULL) && l4_is_valid_cap(*mapped_rm)) 168 { 169 _env.rm = *mapped_rm; 170 return L4_EOK; 171 } 172 else 173 { 174 _env.rm = allocate_cap(); 175 *mapped_rm = _env.rm; 176 return ipc_map_capability(_task, (struct ipc_mapped_cap) {_env.rm, rm, L4_CAP_FPAGE_RWS, 0}); 177 } 178 } 179 180 /* Set the parent of the new thread. */ 181 182 long Process::set_parent(l4_cap_idx_t parent, l4_cap_idx_t *mapped_parent) 183 { 184 *mapped_parent = _env.parent; 185 return ipc_map_capability(_task, (struct ipc_mapped_cap) {_env.parent, parent, L4_CAP_FPAGE_RWS, 0}); 186 } 187 188 /* Map capabilities into the task, counting them if indicated. If capability 189 indexes are obtained using the allocate_cap method, then they do not need to 190 be counted again. */ 191 192 long Process::map_capabilities(struct ipc_mapped_cap mapped_caps[], 193 bool to_count) 194 { 195 unsigned int num_mapped_caps; 196 long err = ipc_map_capabilities(_task, mapped_caps, to_count ? &num_mapped_caps : NULL); 197 198 if (to_count) 199 _env.first_free_cap += num_mapped_caps; 200 201 return err; 202 } 203 204 /* Create, initialise and start a thread. */ 205 206 long Process::thread_start(l4_addr_t program_start, Stack &st, 207 l4_cap_idx_t *thread, l4_cap_idx_t *mapped_thread) 208 { 209 long err; 210 211 err = create_thread(thread); 212 213 if (err) 214 return err; 215 216 /* Obtain UTCB area details for the thread. */ 217 218 l4_fpage_t utcb_fpage = get_utcb_fpage(_thread_number, 1); 219 220 _env.utcb_area = utcb_fpage; 221 _env.first_free_utcb = l4_fpage_memaddr(utcb_fpage) + L4_UTCB_OFFSET; 222 223 /* Initialise the thread with pager, UTCB and task details. */ 224 225 l4_thread_control_start(); 226 l4_thread_control_pager(_env.rm); 227 l4_thread_control_exc_handler(_env.rm); 228 l4_thread_control_bind((l4_utcb_t *) l4_fpage_memaddr(_env.utcb_area), _task); 229 230 err = l4_error(l4_thread_control_commit(*thread)); 231 232 if (err) 233 { 234 ipc_cap_free(*thread); 235 return err; 236 } 237 238 /* Map the thread capability to the task using a distinct capability index. */ 239 240 _env.main_thread = allocate_cap(); 241 242 ipc_map_capability(_task, (struct ipc_mapped_cap) {_env.main_thread, *thread, L4_CAP_FPAGE_RWS, 0}); 243 244 /* Populate the initial environment in the thread. */ 245 246 st.set_l4re_aux(&_aux); 247 st.set_l4re_env(&_env); 248 249 /* Reserve some extra space for capabilities used by this thread. 250 NOTE: Surely the capability allocator should be able to avoid conflicts, 251 but concurrency issues have been observed before, leading to various 252 measures in libipc. */ 253 254 _env.first_free_cap += 0x20; 255 256 /* Set the start details. */ 257 258 err = l4_error(l4_thread_ex_regs(*thread, program_start, st.start_address(), 0)); 259 260 if (err) 261 return err; 262 263 /* Select a new thread. */ 264 265 _thread_number++; 266 267 /* Start the thread. */ 268 269 l4_sched_param_t sp = l4_sched_param(L4RE_MAIN_THREAD_PRIO); 270 271 *mapped_thread = _env.main_thread; 272 return l4_error(l4_scheduler_run_thread(l4re_env()->scheduler, *thread, &sp)); 273 } 274 275 /* vim: tabstop=2 expandtab shiftwidth=2 276 */