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 _thread_number = 0; 58 59 /* Populate the common initial environment for the threads. */ 60 61 _env.factory = L4_BASE_FACTORY_CAP; 62 _env.log = L4_BASE_LOG_CAP; 63 _env.scheduler = L4_BASE_SCHEDULER_CAP; 64 _env.mem_alloc = L4_EXEC_MA_CAP; 65 _env.parent = L4_EXEC_PARENT_CAP; 66 67 /* Capability details that are updated for each thread. Note that the region 68 mapper is redefined, but it would traditionally employ the given index. */ 69 70 _env.main_thread = L4_BASE_THREAD_CAP; 71 _env.rm = L4_EXEC_RM_CAP; 72 _env.first_free_cap = L4_EXEC_FIRST_FREE_CAP_INDEX; 73 74 /* Populate auxiliary information. */ 75 76 _aux.kip_ds = L4_EXEC_KIP_CAP; 77 _aux.dbg_lvl = 0; 78 _aux.ldr_flags = 0; 79 } 80 81 /* Capability index allocation. */ 82 83 l4_cap_idx_t Process::allocate_cap() 84 { 85 return (_env.first_free_cap++ << L4_CAP_SHIFT); 86 } 87 88 /* Task and thread initialisation. */ 89 90 long Process::create_task(unsigned int threads) 91 { 92 _task = ipc_cap_alloc(); 93 94 if (l4_is_invalid_cap(_task)) 95 return -L4_ENOMEM; 96 97 return l4_error(l4_factory_create_task(l4re_env()->factory, _task, get_utcb_fpage(0, threads))); 98 } 99 100 long Process::create_thread(l4_cap_idx_t *thread) 101 { 102 *thread = ipc_cap_alloc(); 103 104 if (l4_is_invalid_cap(*thread)) 105 return -L4_ENOMEM; 106 107 return l4_error(l4_factory_create_thread(l4re_env()->factory, *thread)); 108 } 109 110 /* Configure the task environment. */ 111 112 long Process::configure_task(l4_cap_idx_t *task, l4_cap_idx_t *rtask, unsigned int threads) 113 { 114 long err = create_task(threads); 115 116 if (err) 117 return err; 118 119 /* Map the KIP into the task. */ 120 121 l4_addr_t kip_start = (l4_addr_t) l4re_kip(); 122 123 err = l4_error(l4_task_map(_task, L4RE_THIS_TASK_CAP, 124 l4_fpage(kip_start, L4_PAGESHIFT, L4_FPAGE_RX), 125 kip_start)); 126 127 if (err) 128 return err; 129 130 /* Define capability mappings for the new task. */ 131 132 struct ipc_mapped_cap mapped_caps[] = { 133 {L4_BASE_TASK_CAP, _task, L4_CAP_FPAGE_RWS, 0}, 134 {_env.factory, l4re_env()->factory, L4_CAP_FPAGE_RWS, 0}, 135 {_env.log, l4re_env()->log, L4_CAP_FPAGE_RWS, 0}, 136 {_env.scheduler, l4re_env()->scheduler, L4_CAP_FPAGE_RWS, 0}, 137 {_env.mem_alloc, l4re_env()->mem_alloc, L4_CAP_FPAGE_RWS, 0}, 138 {0, L4_INVALID_CAP, 0, 0}, 139 }; 140 141 /* Return the capability details for the task. */ 142 143 *task = _task; 144 *rtask = L4_BASE_TASK_CAP; 145 146 return map_capabilities(mapped_caps, false); 147 } 148 149 /* Configure the thread environment, employing the given server as the region 150 mapper. Return the capability index for the server in the new task. */ 151 152 long Process::configure_thread(l4_cap_idx_t server, l4_cap_idx_t *mapped_cap) 153 { 154 /* Employ a distinct region mapper for each thread's environment, this acting 155 as pager. */ 156 157 if ((mapped_cap != NULL) && l4_is_valid_cap(*mapped_cap)) 158 { 159 _env.rm = *mapped_cap; 160 return L4_EOK; 161 } 162 else 163 { 164 _env.rm = allocate_cap(); 165 *mapped_cap = _env.rm; 166 return ipc_map_capability(_task, (struct ipc_mapped_cap) {_env.rm, server, L4_CAP_FPAGE_RWS, 0}); 167 } 168 } 169 170 /* Set the parent of the new thread. */ 171 172 long Process::set_parent(l4_cap_idx_t parent, l4_cap_idx_t *rparent) 173 { 174 *rparent = _env.parent; 175 return ipc_map_capability(_task, (struct ipc_mapped_cap) {_env.parent, parent, L4_CAP_FPAGE_RWS, 0}); 176 } 177 178 /* Map capabilities into the task, counting them if indicated. */ 179 180 long Process::map_capabilities(struct ipc_mapped_cap mapped_caps[], 181 bool to_count) 182 { 183 unsigned int num_mapped_caps; 184 long err = ipc_map_capabilities(_task, mapped_caps, to_count ? &num_mapped_caps : NULL); 185 186 if (to_count) 187 _env.first_free_cap += num_mapped_caps; 188 189 return err; 190 } 191 192 /* Create, initialise and start a thread. */ 193 194 long Process::thread_start(l4_addr_t program_start, Stack &st, l4_cap_idx_t *thread, l4_cap_idx_t *rthread) 195 { 196 long err; 197 198 err = create_thread(thread); 199 200 if (err) 201 return err; 202 203 /* Obtain UTCB area details for the thread. */ 204 205 l4_fpage_t utcb_fpage = get_utcb_fpage(_thread_number, 1); 206 207 _env.utcb_area = utcb_fpage; 208 _env.first_free_utcb = l4_fpage_memaddr(utcb_fpage); 209 210 /* Initialise the thread with pager, UTCB and task details. */ 211 212 l4_thread_control_start(); 213 l4_thread_control_pager(_env.rm); 214 l4_thread_control_exc_handler(_env.rm); 215 l4_thread_control_bind((l4_utcb_t *) l4_fpage_memaddr(_env.utcb_area), _task); 216 217 err = l4_error(l4_thread_control_commit(*thread)); 218 219 if (err) 220 { 221 ipc_cap_free(*thread); 222 return err; 223 } 224 225 /* Map the thread capability to the task using a distinct capability index. */ 226 227 _env.main_thread = allocate_cap(); 228 229 ipc_map_capability(_task, (struct ipc_mapped_cap) {_env.main_thread, *thread, L4_CAP_FPAGE_RWS, 0}); 230 231 /* Populate the initial environment in the thread. */ 232 233 st.set_l4re_aux(&_aux); 234 st.set_l4re_env(&_env); 235 236 /* Reserve some extra space for capabilities used by this thread. 237 NOTE: Surely the capability allocator should be able to avoid conflicts, 238 but concurrency issues have been observed before, leading to various 239 measures in libipc. */ 240 241 _env.first_free_cap += 0x20; 242 243 /* Set the start details. */ 244 245 err = l4_error(l4_thread_ex_regs(*thread, program_start, st.start_address(), 0)); 246 247 if (err) 248 return err; 249 250 /* Select a new thread. */ 251 252 _thread_number++; 253 254 /* Start the thread. */ 255 256 l4_sched_param_t sp = l4_sched_param(L4RE_MAIN_THREAD_PRIO); 257 258 *rthread = _env.main_thread; 259 return l4_error(l4_scheduler_run_thread(l4re_env()->scheduler, *thread, &sp)); 260 } 261 262 /* vim: tabstop=2 expandtab shiftwidth=2 263 */