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      1 /*	$NetBSD: kern_stub.c,v 1.55 2026/07/17 02:19:29 thorpej Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2007, 2008 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     26  * POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 /*
     30  * Copyright (c) 1982, 1986, 1991, 1993
     31  *	The Regents of the University of California.  All rights reserved.
     32  *
     33  * Redistribution and use in source and binary forms, with or without
     34  * modification, are permitted provided that the following conditions
     35  * are met:
     36  * 1. Redistributions of source code must retain the above copyright
     37  *    notice, this list of conditions and the following disclaimer.
     38  * 2. Redistributions in binary form must reproduce the above copyright
     39  *    notice, this list of conditions and the following disclaimer in the
     40  *    documentation and/or other materials provided with the distribution.
     41  * 3. Neither the name of the University nor the names of its contributors
     42  *    may be used to endorse or promote products derived from this software
     43  *    without specific prior written permission.
     44  *
     45  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     55  * SUCH DAMAGE.
     56  *
     57  *	@(#)subr_xxx.c	8.3 (Berkeley) 3/29/95
     58  */
     59 
     60 /*
     61  * Stubs for system calls and facilities not included in the system.
     62  */
     63 
     64 #include <sys/cdefs.h>
     65 __KERNEL_RCSID(0, "$NetBSD: kern_stub.c,v 1.55 2026/07/17 02:19:29 thorpej Exp $");
     66 
     67 #ifdef _KERNEL_OPT
     68 #include "opt_ktrace.h"
     69 #include "opt_sysv.h"
     70 #include "opt_modular.h"
     71 #endif
     72 
     73 #include <sys/param.h>
     74 
     75 #include <sys/bus.h>
     76 #include <sys/cpu.h>
     77 #include <sys/fstypes.h>
     78 #include <sys/intr.h>
     79 #include <sys/kernel.h>
     80 #include <sys/ktrace.h>
     81 #include <sys/module.h>
     82 #include <sys/proc.h>
     83 #include <sys/sdt.h>
     84 #include <sys/signalvar.h>
     85 #include <sys/syscall.h>
     86 #include <sys/userconf.h>
     87 
     88 bool default_bus_space_is_equal(bus_space_tag_t, bus_space_tag_t);
     89 bool default_bus_space_handle_is_equal(bus_space_tag_t, bus_space_handle_t,
     90     bus_space_handle_t);
     91 
     92 /*
     93  * SYSV Semaphores, Shared Memory, Message Queues
     94  */
     95 #ifndef MODULAR
     96 #ifndef SYSVMSG
     97 __strong_alias(msgctl1,enosys);
     98 #endif
     99 #ifndef SYSVSHM
    100 __strong_alias(shmctl1,enosys);
    101 #endif
    102 #ifndef SYSVSEM
    103  __strong_alias(semctl1,enosys);
    104 #endif
    105 #endif
    106 
    107 /*
    108  * ktrace stubs.  ktruser() goes to enosys as we want to fail the syscall,
    109  * but not kill the process: utrace() is a debugging feature.
    110  */
    111 #ifndef KTRACE
    112 __strong_alias(ktr_csw,nullop);		/* Probes */
    113 __strong_alias(ktr_emul,nullop);
    114 __strong_alias(ktr_geniov,nullop);
    115 __strong_alias(ktr_genio,nullop);
    116 __strong_alias(ktr_mibio,nullop);
    117 __strong_alias(ktr_namei,nullop);
    118 __strong_alias(ktr_namei2,nullop);
    119 __strong_alias(ktr_psig,nullop);
    120 __strong_alias(ktr_syscall,nullop);
    121 __strong_alias(ktr_sysret,nullop);
    122 __strong_alias(ktr_kuser,nullop);
    123 __strong_alias(ktr_mib,nullop);
    124 __strong_alias(ktr_execarg,nullop);
    125 __strong_alias(ktr_execenv,nullop);
    126 __strong_alias(ktr_execfd,nullop);
    127 __strong_alias(ktr_sigmask,nullop);
    128 
    129 __strong_alias(sys_fktrace,sys_nosys);	/* Syscalls */
    130 __strong_alias(sys_ktrace,sys_nosys);
    131 __strong_alias(sys_utrace,sys_nosys);
    132 
    133 int	ktrace_on;			/* Misc */
    134 __strong_alias(ktruser,enosys);
    135 __strong_alias(ktr_point,nullop);
    136 #endif	/* KTRACE */
    137 
    138 __weak_alias(device_register, voidop);
    139 __weak_alias(device_register_post_config, voidop);
    140 __weak_alias(spldebug_start, voidop);
    141 __weak_alias(spldebug_stop, voidop);
    142 __weak_alias(machdep_init,nullop);
    143 __weak_alias(pci_chipset_tag_create, eopnotsupp);
    144 __weak_alias(pci_chipset_tag_destroy, voidop);
    145 __weak_alias(bus_space_reserve, eopnotsupp);
    146 __weak_alias(bus_space_reserve_subregion, eopnotsupp);
    147 __weak_alias(bus_space_release, voidop);
    148 __weak_alias(bus_space_reservation_map, eopnotsupp);
    149 __weak_alias(bus_space_reservation_unmap, voidop);
    150 __weak_alias(bus_dma_tag_create, eopnotsupp);
    151 __weak_alias(bus_dma_tag_destroy, voidop);
    152 __weak_alias(bus_space_tag_create, eopnotsupp);
    153 __weak_alias(bus_space_tag_destroy, voidop);
    154 __strict_weak_alias(bus_space_is_equal, default_bus_space_is_equal);
    155 __strict_weak_alias(bus_space_handle_is_equal,
    156     default_bus_space_handle_is_equal);
    157 __weak_alias(userconf_bootinfo, voidop);
    158 __weak_alias(userconf_init, voidop);
    159 __weak_alias(userconf_prompt, voidop);
    160 
    161 #ifdef MODULAR
    162 __weak_alias(module_init_md, voidop);
    163 #endif
    164 
    165 __weak_alias(kobj_renamespace, nullop);
    166 
    167 __weak_alias(interrupt_get_count, nullop);
    168 __weak_alias(interrupt_get_assigned, voidop);
    169 __weak_alias(interrupt_get_available, voidop);
    170 __weak_alias(interrupt_get_devname, voidop);
    171 __weak_alias(interrupt_construct_intrids, nullret);
    172 __weak_alias(interrupt_destruct_intrids, voidop);
    173 __weak_alias(interrupt_distribute, eopnotsupp);
    174 __weak_alias(interrupt_distribute_handler, eopnotsupp);
    175 
    176 __weak_alias(ipi_register, trueop);	/* just a low non-zero value */
    177 __weak_alias(ipi_unregister, voidop);
    178 __weak_alias(ipi_trigger, voidop);
    179 __weak_alias(ipi_trigger_multi, voidop);
    180 __weak_alias(ipi_trigger_broadcast, voidop);
    181 
    182 __weak_alias(ipi_unicast, trueop);
    183 __weak_alias(ipi_multicast, voidop);
    184 __weak_alias(ipi_broadcast, voidop);
    185 __weak_alias(ipi_wait, voidop);
    186 
    187 /*
    188  * Scheduler activations system calls.  These need to remain until libc's
    189  * major version is bumped.
    190  */
    191 __strong_alias(sys_sa_register,sys_nosys);
    192 __strong_alias(sys_sa_stacks,sys_nosys);
    193 __strong_alias(sys_sa_enable,sys_nosys);
    194 __strong_alias(sys_sa_setconcurrency,sys_nosys);
    195 __strong_alias(sys_sa_yield,sys_nosys);
    196 __strong_alias(sys_sa_preempt,sys_nosys);
    197 __strong_alias(sys_sa_unblockyield,sys_nosys);
    198 
    199 /*
    200  * Stubs for compat_netbsd32.
    201  */
    202 __strong_alias(dosa_register,sys_nosys);
    203 __strong_alias(sa_stacks1,sys_nosys);
    204 
    205 /*
    206  * Stubs for drivers.  See sys/conf.h.
    207  */
    208 __strong_alias(devenodev,enodev);
    209 __strong_alias(deveopnotsupp,eopnotsupp);
    210 __strong_alias(devnullop,nullop);
    211 __strong_alias(ttyenodev,enodev);
    212 __strong_alias(ttyvenodev,voidop);
    213 __strong_alias(ttyvnullop,nullop);
    214 
    215 /*
    216  * Stubs for architectures that do not support kernel preemption.
    217  */
    218 #ifndef __HAVE_PREEMPTION
    219 bool
    220 cpu_kpreempt_enter(uintptr_t where, int s)
    221 {
    222 
    223 	return false;
    224 }
    225 
    226 void
    227 cpu_kpreempt_exit(uintptr_t where)
    228 {
    229 
    230 }
    231 
    232 bool
    233 cpu_kpreempt_disabled(void)
    234 {
    235 
    236 	return true;
    237 }
    238 #else
    239 # ifndef MULTIPROCESSOR
    240 #   error __HAVE_PREEMPTION requires MULTIPROCESSOR
    241 # endif
    242 #endif	/* !__HAVE_PREEMPTION */
    243 
    244 int
    245 sys_nosys(struct lwp *l, const void *v, register_t *retval)
    246 {
    247 
    248 	mutex_enter(&proc_lock);
    249 	psignal(l->l_proc, SIGSYS);
    250 	mutex_exit(&proc_lock);
    251 	return SET_ERROR(ENOSYS);
    252 }
    253 
    254 /*
    255  * Unsupported device function (e.g. writing to read-only device).
    256  */
    257 int
    258 enodev(void)
    259 {
    260 
    261 	return SET_ERROR(ENODEV);
    262 }
    263 
    264 /*
    265  * Unconfigured device function; driver not configured.
    266  */
    267 int
    268 enxio(void)
    269 {
    270 
    271 	return SET_ERROR(ENXIO);
    272 }
    273 
    274 /*
    275  * Unsupported ioctl function.
    276  */
    277 int
    278 enoioctl(void)
    279 {
    280 
    281 	return SET_ERROR(ENOTTY);
    282 }
    283 
    284 /*
    285  * Unsupported system function.
    286  * This is used for an otherwise-reasonable operation
    287  * that is not supported by the current system binary.
    288  */
    289 int
    290 enosys(void)
    291 {
    292 
    293 	return SET_ERROR(ENOSYS);
    294 }
    295 
    296 /*
    297  * Return error for operation not supported
    298  * on a specific object or file type.
    299  */
    300 int
    301 eopnotsupp(void)
    302 {
    303 
    304 	return SET_ERROR(EOPNOTSUPP);
    305 }
    306 
    307 /*
    308  * Generic null operation, void return value.
    309  */
    310 void
    311 voidop(void)
    312 {
    313 }
    314 
    315 /*
    316  * Generic null operation, always returns success.
    317  */
    318 int
    319 nullop(void *v)
    320 {
    321 
    322 	return (0);
    323 }
    324 
    325 /*
    326  * Generic "true" operation, always returns true (but as an int).
    327  */
    328 int
    329 trueop(void)
    330 {
    331 	return true;
    332 }
    333 
    334 /*
    335  * Generic null operation, always returns null.
    336  */
    337 void *
    338 nullret(void)
    339 {
    340 
    341 	return (NULL);
    342 }
    343 
    344 bool
    345 default_bus_space_handle_is_equal(bus_space_tag_t t,
    346     bus_space_handle_t h1, bus_space_handle_t h2)
    347 {
    348 
    349 	return memcmp(&h1, &h2, sizeof(h1)) == 0;
    350 }
    351 
    352 bool
    353 default_bus_space_is_equal(bus_space_tag_t t1, bus_space_tag_t t2)
    354 {
    355 
    356 	return memcmp(&t1, &t2, sizeof(t1)) == 0;
    357 }
    358 
    359 /* Stubs for architectures with no kernel FPU access.  */
    360 __weak_alias(kthread_fpu_enter_md, voidop);
    361 __weak_alias(kthread_fpu_exit_md, voidop);
    362