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      1 /*	$NetBSD: linux_sched.c,v 1.87 2025/11/10 15:41:38 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1999, 2019 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
      9  * NASA Ames Research Center; by Matthias Scheler.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     30  * POSSIBILITY OF SUCH DAMAGE.
     31  */
     32 
     33 /*
     34  * Linux compatibility module. Try to deal with scheduler related syscalls.
     35  */
     36 
     37 #include <sys/cdefs.h>
     38 __KERNEL_RCSID(0, "$NetBSD: linux_sched.c,v 1.87 2025/11/10 15:41:38 christos Exp $");
     39 
     40 #include <sys/param.h>
     41 #include <sys/mount.h>
     42 #include <sys/proc.h>
     43 #include <sys/systm.h>
     44 #include <sys/sysctl.h>
     45 #include <sys/syscallargs.h>
     46 #include <sys/wait.h>
     47 #include <sys/kauth.h>
     48 #include <sys/ptrace.h>
     49 #include <sys/atomic.h>
     50 
     51 #include <sys/cpu.h>
     52 
     53 #include <compat/linux/common/linux_types.h>
     54 #include <compat/linux/common/linux_signal.h>
     55 #include <compat/linux/common/linux_emuldata.h>
     56 #include <compat/linux/common/linux_ipc.h>
     57 #include <compat/linux/common/linux_sem.h>
     58 #include <compat/linux/common/linux_exec.h>
     59 #include <compat/linux/common/linux_machdep.h>
     60 
     61 #include <compat/linux/linux_syscallargs.h>
     62 
     63 #include <compat/linux/common/linux_sched.h>
     64 
     65 #include <compat/linux/common/linux_prctl.h>
     66 
     67 static int linux_clone_nptl(struct lwp *, const struct linux_sys_clone_args *,
     68     register_t *);
     69 
     70 /* Unlike Linux, dynamically calculate CPU mask size */
     71 #define	LINUX_CPU_MASK_SIZE (sizeof(long) * ((ncpu + LONG_BIT - 1) / LONG_BIT))
     72 
     73 #if DEBUG_LINUX
     74 #define DPRINTF(x, ...) uprintf(x, __VA_ARGS__)
     75 #else
     76 #define DPRINTF(x, ...)
     77 #endif
     78 
     79 static void
     80 linux_child_return(void *arg)
     81 {
     82 	struct lwp *l = arg;
     83 	struct proc *p = l->l_proc;
     84 	struct linux_emuldata *led = l->l_emuldata;
     85 	void *ctp = led->led_child_tidptr;
     86 	int error;
     87 
     88 	if (ctp) {
     89 		if ((error = copyout(&p->p_pid, ctp, sizeof(p->p_pid))) != 0)
     90 			printf("%s: LINUX_CLONE_CHILD_SETTID "
     91 			    "failed (child_tidptr = %p, tid = %d error =%d)\n",
     92 			    __func__, ctp, p->p_pid, error);
     93 	}
     94 	child_return(arg);
     95 }
     96 
     97 int
     98 linux_sys_clone(struct lwp *l, const struct linux_sys_clone_args *uap,
     99     register_t *retval)
    100 {
    101 	/* {
    102 		syscallarg(int) flags;
    103 		syscallarg(void *) stack;
    104 		syscallarg(void *) parent_tidptr;
    105 		syscallarg(void *) tls;
    106 		syscallarg(void *) child_tidptr;
    107 	} */
    108 	struct linux_emuldata *led;
    109 	int flags, sig, error;
    110 
    111 	/*
    112 	 * We don't support the Linux CLONE_PID or CLONE_PTRACE flags.
    113 	 */
    114 	if (SCARG(uap, flags) & (LINUX_CLONE_PID|LINUX_CLONE_PTRACE))
    115 		return EINVAL;
    116 
    117 	/*
    118 	 * Thread group implies shared signals. Shared signals
    119 	 * imply shared VM. This matches what Linux kernel does.
    120 	 */
    121 	if (SCARG(uap, flags) & LINUX_CLONE_THREAD
    122 	    && (SCARG(uap, flags) & LINUX_CLONE_SIGHAND) == 0)
    123 		return EINVAL;
    124 	if (SCARG(uap, flags) & LINUX_CLONE_SIGHAND
    125 	    && (SCARG(uap, flags) & LINUX_CLONE_VM) == 0)
    126 		return EINVAL;
    127 
    128 	/*
    129 	 * The thread group flavor is implemented totally differently.
    130 	 */
    131 	if (SCARG(uap, flags) & LINUX_CLONE_THREAD)
    132 		return linux_clone_nptl(l, uap, retval);
    133 
    134 	flags = 0;
    135 	if (SCARG(uap, flags) & LINUX_CLONE_VM)
    136 		flags |= FORK_SHAREVM;
    137 	if (SCARG(uap, flags) & LINUX_CLONE_FS)
    138 		flags |= FORK_SHARECWD;
    139 	if (SCARG(uap, flags) & LINUX_CLONE_FILES)
    140 		flags |= FORK_SHAREFILES;
    141 	if (SCARG(uap, flags) & LINUX_CLONE_SIGHAND)
    142 		flags |= FORK_SHARESIGS;
    143 	if (SCARG(uap, flags) & LINUX_CLONE_VFORK)
    144 		flags |= FORK_PPWAIT;
    145 
    146 	sig = SCARG(uap, flags) & LINUX_CLONE_CSIGNAL;
    147 	if (sig < 0 || sig >= LINUX__NSIG)
    148 		return EINVAL;
    149 	sig = linux_to_native_signo[sig];
    150 
    151 	if (SCARG(uap, flags) & LINUX_CLONE_CHILD_SETTID) {
    152 		led = l->l_emuldata;
    153 		led->led_child_tidptr = SCARG(uap, child_tidptr);
    154 	}
    155 
    156 	/*
    157 	 * Note that Linux does not provide a portable way of specifying
    158 	 * the stack area; the caller must know if the stack grows up
    159 	 * or down.  So, we pass a stack size of 0, so that the code
    160 	 * that makes this adjustment is a noop.
    161 	 */
    162 	if ((error = fork1(l, flags, sig, SCARG(uap, stack), 0,
    163 	    linux_child_return, NULL, retval)) != 0) {
    164 		DPRINTF("%s: fork1: error %d\n", __func__, error);
    165 		return error;
    166 	}
    167 
    168 	return 0;
    169 }
    170 
    171 
    172 int
    173 linux_sys_clone3(struct lwp *l, const struct linux_sys_clone3_args *uap, register_t *retval)
    174 {
    175 	struct linux_user_clone3_args cl_args;
    176 	struct linux_sys_clone_args clone_args;
    177 	int error;
    178 
    179 	if (SCARG(uap, size) != sizeof(cl_args)) {
    180 	    DPRINTF("%s: Invalid size less or more\n", __func__);
    181 	    return EINVAL;
    182 	}
    183 
    184 	error = copyin(SCARG(uap, cl_args), &cl_args, SCARG(uap, size));
    185 	if (error) {
    186 		DPRINTF("%s: Copyin failed: %d\n", __func__, error);
    187 		return error;
    188 	}
    189 
    190 	DPRINTF("%s: Flags: %#jx\n", __func__, (intmax_t)cl_args.flags);
    191 
    192 	/* Define allowed flags */
    193 	if (cl_args.flags & LINUX_CLONE_UNIMPLEMENTED_FLAGS) {
    194 		DPRINTF("%s: Unsupported flags for clone3: %#" PRIx64 "\n",
    195 		    __func__, cl_args.flags & LINUX_CLONE_UNIMPLEMENTED_FLAGS);
    196 		return EOPNOTSUPP;
    197 	}
    198 	if (cl_args.flags & ~LINUX_CLONE_ALLOWED_FLAGS) {
    199 		DPRINTF("%s: Disallowed flags for clone3: %#" PRIx64 "\n",
    200 		    __func__, cl_args.flags & ~LINUX_CLONE_ALLOWED_FLAGS);
    201 		return EINVAL;
    202 	}
    203 
    204 #if 0
    205 	// XXX: this is wrong, exit_signal is the signal to deliver to the
    206 	// process upon exit.
    207 	if ((cl_args.exit_signal & ~(uint64_t)LINUX_CLONE_CSIGNAL) != 0){
    208 		DPRINTF("%s: Disallowed flags for clone3: %#x\n", __func__,
    209 		    cl_args.exit_signal & ~(uint64_t)LINUX_CLONE_CSIGNAL);
    210 		return EINVAL;
    211 	}
    212 #endif
    213 
    214 	if (cl_args.stack == 0 && cl_args.stack_size != 0) {
    215 		DPRINTF("%s: Stack is NULL but stack size is not 0\n",
    216 		    __func__);
    217 		return EINVAL;
    218 	}
    219 	if (cl_args.stack != 0 && cl_args.stack_size == 0) {
    220 		DPRINTF("%s: Stack is not NULL but stack size is 0\n",
    221 		    __func__);
    222 		return EINVAL;
    223 	}
    224 
    225 	int flags = cl_args.flags & LINUX_CLONE_ALLOWED_FLAGS;
    226 #if 0
    227 	int sig = cl_args.exit_signal & LINUX_CLONE_CSIGNAL;
    228 #endif
    229 	// XXX: Pidfd member handling
    230 	// XXX: we don't have cgroups
    231 	// XXX: what to do with tid_set and tid_set_size
    232 	// XXX: clone3 has stacksize, instead implement clone as a clone3
    233 	// wrapper.
    234 	SCARG(&clone_args, flags) = flags;
    235 #ifdef __MACHINE_STACK_GROWS_UP
    236 	SCARG(&clone_args, stack) = (void *)(uintptr_t)cl_args.stack;
    237 #else
    238 	SCARG(&clone_args, stack) =
    239 	    (void *)(uintptr_t)((uintptr_t)cl_args.stack + cl_args.stack_size);
    240 #endif
    241 	SCARG(&clone_args, parent_tidptr) =
    242 	    (void *)(intptr_t)cl_args.parent_tid;
    243 	SCARG(&clone_args, tls) =
    244 	    (void *)(intptr_t)cl_args.tls;
    245 	SCARG(&clone_args, child_tidptr) =
    246 	    (void *)(intptr_t)cl_args.child_tid;
    247 
    248 	return linux_sys_clone(l, &clone_args, retval);
    249 }
    250 
    251 static int
    252 linux_clone_nptl(struct lwp *l, const struct linux_sys_clone_args *uap, register_t *retval)
    253 {
    254 	/* {
    255 		syscallarg(int) flags;
    256 		syscallarg(void *) stack;
    257 		syscallarg(void *) parent_tidptr;
    258 		syscallarg(void *) tls;
    259 		syscallarg(void *) child_tidptr;
    260 	} */
    261 	struct proc *p;
    262 	struct lwp *l2;
    263 	struct linux_emuldata *led;
    264 	void *parent_tidptr, *tls, *child_tidptr;
    265 	vaddr_t uaddr;
    266 	lwpid_t lid;
    267 	int flags, error;
    268 
    269 	p = l->l_proc;
    270 	flags = SCARG(uap, flags);
    271 	parent_tidptr = SCARG(uap, parent_tidptr);
    272 	tls = SCARG(uap, tls);
    273 	child_tidptr = SCARG(uap, child_tidptr);
    274 
    275 	uaddr = uvm_uarea_alloc();
    276 	if (__predict_false(uaddr == 0)) {
    277 		return ENOMEM;
    278 	}
    279 
    280 	error = lwp_create(l, p, uaddr, LWP_DETACHED,
    281 	    SCARG(uap, stack), 0, child_return, NULL, &l2, l->l_class,
    282 	    &l->l_sigmask, &l->l_sigstk);
    283 	if (__predict_false(error)) {
    284 		DPRINTF("%s: lwp_create error=%d\n", __func__, error);
    285 		uvm_uarea_free(uaddr);
    286 		return error;
    287 	}
    288 	lid = l2->l_lid;
    289 
    290 	/* LINUX_CLONE_CHILD_CLEARTID: clear TID in child's memory on exit() */
    291 	if (flags & LINUX_CLONE_CHILD_CLEARTID) {
    292 		led = l2->l_emuldata;
    293 		led->led_clear_tid = child_tidptr;
    294 	}
    295 
    296 	/* LINUX_CLONE_PARENT_SETTID: store child's TID in parent's memory */
    297 	if (flags & LINUX_CLONE_PARENT_SETTID) {
    298 		if ((error = copyout(&lid, parent_tidptr, sizeof(lid))) != 0)
    299 			printf("%s: LINUX_CLONE_PARENT_SETTID "
    300 			    "failed (parent_tidptr = %p tid = %d error=%d)\n",
    301 			    __func__, parent_tidptr, lid, error);
    302 	}
    303 
    304 	/* LINUX_CLONE_CHILD_SETTID: store child's TID in child's memory  */
    305 	if (flags & LINUX_CLONE_CHILD_SETTID) {
    306 		if ((error = copyout(&lid, child_tidptr, sizeof(lid))) != 0)
    307 			printf("%s: LINUX_CLONE_CHILD_SETTID "
    308 			    "failed (child_tidptr = %p, tid = %d error=%d)\n",
    309 			    __func__, child_tidptr, lid, error);
    310 	}
    311 
    312 	if (flags & LINUX_CLONE_SETTLS) {
    313 		error = LINUX_LWP_SETPRIVATE(l2, tls);
    314 		if (error) {
    315 			DPRINTF("%s: LINUX_LWP_SETPRIVATE %d\n", __func__,
    316 			    error);
    317 			lwp_exit(l2);
    318 			return error;
    319 		}
    320 	}
    321 
    322 	/* Set the new LWP running. */
    323 	lwp_start(l2, 0);
    324 
    325 	retval[0] = lid;
    326 	retval[1] = 0;
    327 	return 0;
    328 }
    329 
    330 /*
    331  * linux realtime priority
    332  *
    333  * - SCHED_RR and SCHED_FIFO tasks have priorities [1,99].
    334  *
    335  * - SCHED_OTHER tasks don't have realtime priorities.
    336  *   in particular, sched_param::sched_priority is always 0.
    337  */
    338 
    339 #define	LINUX_SCHED_RTPRIO_MIN	1
    340 #define	LINUX_SCHED_RTPRIO_MAX	99
    341 
    342 static int
    343 sched_linux2native(int linux_policy, struct linux_sched_param *linux_params,
    344     int *native_policy, struct sched_param *native_params)
    345 {
    346 
    347 	switch (linux_policy) {
    348 	case LINUX_SCHED_OTHER:
    349 		if (native_policy != NULL) {
    350 			*native_policy = SCHED_OTHER;
    351 		}
    352 		break;
    353 
    354 	case LINUX_SCHED_FIFO:
    355 		if (native_policy != NULL) {
    356 			*native_policy = SCHED_FIFO;
    357 		}
    358 		break;
    359 
    360 	case LINUX_SCHED_RR:
    361 		if (native_policy != NULL) {
    362 			*native_policy = SCHED_RR;
    363 		}
    364 		break;
    365 
    366 	default:
    367 		return EINVAL;
    368 	}
    369 
    370 	if (linux_params != NULL) {
    371 		int prio = linux_params->sched_priority;
    372 
    373 		KASSERT(native_params != NULL);
    374 
    375 		if (linux_policy == LINUX_SCHED_OTHER) {
    376 			if (prio != 0) {
    377 				return EINVAL;
    378 			}
    379 			native_params->sched_priority = PRI_NONE; /* XXX */
    380 		} else {
    381 			if (prio < LINUX_SCHED_RTPRIO_MIN ||
    382 			    prio > LINUX_SCHED_RTPRIO_MAX) {
    383 				return EINVAL;
    384 			}
    385 			native_params->sched_priority =
    386 			    (prio - LINUX_SCHED_RTPRIO_MIN)
    387 			    * (SCHED_PRI_MAX - SCHED_PRI_MIN)
    388 			    / (LINUX_SCHED_RTPRIO_MAX - LINUX_SCHED_RTPRIO_MIN)
    389 			    + SCHED_PRI_MIN;
    390 		}
    391 	}
    392 
    393 	return 0;
    394 }
    395 
    396 static int
    397 sched_native2linux(int native_policy, struct sched_param *native_params,
    398     int *linux_policy, struct linux_sched_param *linux_params)
    399 {
    400 
    401 	switch (native_policy) {
    402 	case SCHED_OTHER:
    403 		if (linux_policy != NULL) {
    404 			*linux_policy = LINUX_SCHED_OTHER;
    405 		}
    406 		break;
    407 
    408 	case SCHED_FIFO:
    409 		if (linux_policy != NULL) {
    410 			*linux_policy = LINUX_SCHED_FIFO;
    411 		}
    412 		break;
    413 
    414 	case SCHED_RR:
    415 		if (linux_policy != NULL) {
    416 			*linux_policy = LINUX_SCHED_RR;
    417 		}
    418 		break;
    419 
    420 	default:
    421 		panic("%s: unknown policy %d\n", __func__, native_policy);
    422 	}
    423 
    424 	if (native_params != NULL) {
    425 		int prio = native_params->sched_priority;
    426 
    427 		KASSERT(prio >= SCHED_PRI_MIN);
    428 		KASSERT(prio <= SCHED_PRI_MAX);
    429 		KASSERT(linux_params != NULL);
    430 
    431 		memset(linux_params, 0, sizeof(*linux_params));
    432 
    433 		DPRINTF("%s: native: policy %d, priority %d\n",
    434 		    __func__, native_policy, prio);
    435 
    436 		if (native_policy == SCHED_OTHER) {
    437 			linux_params->sched_priority = 0;
    438 		} else {
    439 			linux_params->sched_priority =
    440 			    (prio - SCHED_PRI_MIN)
    441 			    * (LINUX_SCHED_RTPRIO_MAX - LINUX_SCHED_RTPRIO_MIN)
    442 			    / (SCHED_PRI_MAX - SCHED_PRI_MIN)
    443 			    + LINUX_SCHED_RTPRIO_MIN;
    444 		}
    445 		DPRINTF("%s: linux: policy %d, priority %d\n",
    446 		    __func__, -1, linux_params->sched_priority);
    447 	}
    448 
    449 	return 0;
    450 }
    451 
    452 int
    453 linux_sys_sched_setparam(struct lwp *l, const struct linux_sys_sched_setparam_args *uap, register_t *retval)
    454 {
    455 	/* {
    456 		syscallarg(linux_pid_t) pid;
    457 		syscallarg(const struct linux_sched_param *) sp;
    458 	} */
    459 	int error, policy;
    460 	struct linux_sched_param lp;
    461 	struct sched_param sp;
    462 
    463 	if (SCARG(uap, pid) < 0 || SCARG(uap, sp) == NULL) {
    464 		error = EINVAL;
    465 		goto out;
    466 	}
    467 
    468 	error = copyin(SCARG(uap, sp), &lp, sizeof(lp));
    469 	if (error)
    470 		goto out;
    471 
    472 	/* We need the current policy in Linux terms. */
    473 	error = do_sched_getparam(SCARG(uap, pid), 0, &policy, NULL);
    474 	if (error)
    475 		goto out;
    476 	error = sched_native2linux(policy, NULL, &policy, NULL);
    477 	if (error)
    478 		goto out;
    479 
    480 	error = sched_linux2native(policy, &lp, &policy, &sp);
    481 	if (error)
    482 		goto out;
    483 
    484 	error = do_sched_setparam(SCARG(uap, pid), 0, policy, &sp);
    485 	if (error)
    486 		goto out;
    487 
    488  out:
    489 	return error;
    490 }
    491 
    492 int
    493 linux_sys_sched_getparam(struct lwp *l, const struct linux_sys_sched_getparam_args *uap, register_t *retval)
    494 {
    495 	/* {
    496 		syscallarg(linux_pid_t) pid;
    497 		syscallarg(struct linux_sched_param *) sp;
    498 	} */
    499 	struct linux_sched_param lp;
    500 	struct sched_param sp;
    501 	int error, policy;
    502 
    503 	if (SCARG(uap, pid) < 0 || SCARG(uap, sp) == NULL) {
    504 		error = EINVAL;
    505 		goto out;
    506 	}
    507 
    508 	error = do_sched_getparam(SCARG(uap, pid), 0, &policy, &sp);
    509 	if (error)
    510 		goto out;
    511 	DPRINTF("%s: native: policy %d, priority %d\n",
    512 	    __func__, policy, sp.sched_priority);
    513 
    514 	error = sched_native2linux(policy, &sp, NULL, &lp);
    515 	if (error)
    516 		goto out;
    517 	DPRINTF("%s: linux: policy %d, priority %d\n",
    518 	    __func__, policy, lp.sched_priority);
    519 
    520 	error = copyout(&lp, SCARG(uap, sp), sizeof(lp));
    521 	if (error)
    522 		goto out;
    523 
    524  out:
    525 	return error;
    526 }
    527 
    528 int
    529 linux_sys_sched_setscheduler(struct lwp *l, const struct linux_sys_sched_setscheduler_args *uap, register_t *retval)
    530 {
    531 	/* {
    532 		syscallarg(linux_pid_t) pid;
    533 		syscallarg(int) policy;
    534 		syscallarg(cont struct linux_sched_param *) sp;
    535 	} */
    536 	int error, policy;
    537 	struct linux_sched_param lp;
    538 	struct sched_param sp;
    539 
    540 	if (SCARG(uap, pid) < 0 || SCARG(uap, sp) == NULL) {
    541 		error = EINVAL;
    542 		goto out;
    543 	}
    544 
    545 	error = copyin(SCARG(uap, sp), &lp, sizeof(lp));
    546 	if (error)
    547 		goto out;
    548 	DPRINTF("%s: linux: policy %d, priority %d\n",
    549 	    __func__, SCARG(uap, policy), lp.sched_priority);
    550 
    551 	error = sched_linux2native(SCARG(uap, policy), &lp, &policy, &sp);
    552 	if (error)
    553 		goto out;
    554 	DPRINTF("%s: native: policy %d, priority %d\n",
    555 	    __func__, policy, sp.sched_priority);
    556 
    557 	error = do_sched_setparam(SCARG(uap, pid), 0, policy, &sp);
    558 	if (error)
    559 		goto out;
    560 
    561  out:
    562 	return error;
    563 }
    564 
    565 int
    566 linux_sys_sched_getscheduler(struct lwp *l, const struct linux_sys_sched_getscheduler_args *uap, register_t *retval)
    567 {
    568 	/* {
    569 		syscallarg(linux_pid_t) pid;
    570 	} */
    571 	int error, policy;
    572 
    573 	*retval = -1;
    574 
    575 	error = do_sched_getparam(SCARG(uap, pid), 0, &policy, NULL);
    576 	if (error)
    577 		goto out;
    578 
    579 	error = sched_native2linux(policy, NULL, &policy, NULL);
    580 	if (error)
    581 		goto out;
    582 
    583 	*retval = policy;
    584 
    585  out:
    586 	return error;
    587 }
    588 
    589 int
    590 linux_sys_sched_yield(struct lwp *l, const void *v, register_t *retval)
    591 {
    592 
    593 	yield();
    594 	return 0;
    595 }
    596 
    597 int
    598 linux_sys_sched_get_priority_max(struct lwp *l, const struct linux_sys_sched_get_priority_max_args *uap, register_t *retval)
    599 {
    600 	/* {
    601 		syscallarg(int) policy;
    602 	} */
    603 
    604 	switch (SCARG(uap, policy)) {
    605 	case LINUX_SCHED_OTHER:
    606 		*retval = 0;
    607 		break;
    608 	case LINUX_SCHED_FIFO:
    609 	case LINUX_SCHED_RR:
    610 		*retval = LINUX_SCHED_RTPRIO_MAX;
    611 		break;
    612 	default:
    613 		return EINVAL;
    614 	}
    615 
    616 	return 0;
    617 }
    618 
    619 int
    620 linux_sys_sched_get_priority_min(struct lwp *l, const struct linux_sys_sched_get_priority_min_args *uap, register_t *retval)
    621 {
    622 	/* {
    623 		syscallarg(int) policy;
    624 	} */
    625 
    626 	switch (SCARG(uap, policy)) {
    627 	case LINUX_SCHED_OTHER:
    628 		*retval = 0;
    629 		break;
    630 	case LINUX_SCHED_FIFO:
    631 	case LINUX_SCHED_RR:
    632 		*retval = LINUX_SCHED_RTPRIO_MIN;
    633 		break;
    634 	default:
    635 		return EINVAL;
    636 	}
    637 
    638 	return 0;
    639 }
    640 
    641 int
    642 linux_sys_exit(struct lwp *l, const struct linux_sys_exit_args *uap, register_t *retval)
    643 {
    644 
    645 	lwp_exit(l);
    646 	return 0;
    647 }
    648 
    649 #ifndef __m68k__
    650 /* Present on everything but m68k */
    651 int
    652 linux_sys_exit_group(struct lwp *l, const struct linux_sys_exit_group_args *uap, register_t *retval)
    653 {
    654 
    655 	return sys_exit(l, (const void *)uap, retval);
    656 }
    657 #endif /* !__m68k__ */
    658 
    659 int
    660 linux_sys_set_tid_address(struct lwp *l, const struct linux_sys_set_tid_address_args *uap, register_t *retval)
    661 {
    662 	/* {
    663 		syscallarg(int *) tidptr;
    664 	} */
    665 	struct linux_emuldata *led;
    666 
    667 	led = (struct linux_emuldata *)l->l_emuldata;
    668 	led->led_clear_tid = SCARG(uap, tid);
    669 	*retval = l->l_lid;
    670 
    671 	return 0;
    672 }
    673 
    674 /* ARGUSED1 */
    675 int
    676 linux_sys_gettid(struct lwp *l, const void *v, register_t *retval)
    677 {
    678 
    679 	*retval = l->l_lid;
    680 	return 0;
    681 }
    682 
    683 /*
    684  * The affinity syscalls assume that the layout of our cpu kcpuset is
    685  * the same as linux's: a linear bitmask.
    686  */
    687 int
    688 linux_sys_sched_getaffinity(struct lwp *l, const struct linux_sys_sched_getaffinity_args *uap, register_t *retval)
    689 {
    690 	/* {
    691 		syscallarg(linux_pid_t) pid;
    692 		syscallarg(unsigned int) len;
    693 		syscallarg(unsigned long *) mask;
    694 	} */
    695 	struct proc *p;
    696 	struct lwp *t;
    697 	kcpuset_t *kcset;
    698 	size_t size;
    699 	cpuid_t i;
    700 	int error;
    701 
    702 	size = LINUX_CPU_MASK_SIZE;
    703 	if (SCARG(uap, len) < size)
    704 		return EINVAL;
    705 
    706 	if (SCARG(uap, pid) == 0) {
    707 		p = curproc;
    708 		mutex_enter(p->p_lock);
    709 		t = curlwp;
    710 	} else {
    711 		t = lwp_find2(-1, SCARG(uap, pid));
    712 		if (__predict_false(t == NULL)) {
    713 			return ESRCH;
    714 		}
    715 		p = t->l_proc;
    716 		KASSERT(mutex_owned(p->p_lock));
    717 	}
    718 
    719 	/* Check the permission */
    720 	if (kauth_authorize_process(l->l_cred,
    721 	    KAUTH_PROCESS_SCHEDULER_GETAFFINITY, p, NULL, NULL, NULL)) {
    722 		mutex_exit(p->p_lock);
    723 		return EPERM;
    724 	}
    725 
    726 	kcpuset_create(&kcset, true);
    727 	lwp_lock(t);
    728 	if (t->l_affinity != NULL)
    729 		kcpuset_copy(kcset, t->l_affinity);
    730 	else {
    731 		/*
    732 		 * All available CPUs should be masked when affinity has not
    733 		 * been set.
    734 		 */
    735 		kcpuset_zero(kcset);
    736 		for (i = 0; i < ncpu; i++)
    737 			kcpuset_set(kcset, i);
    738 	}
    739 	lwp_unlock(t);
    740 	mutex_exit(p->p_lock);
    741 	error = kcpuset_copyout(kcset, (cpuset_t *)SCARG(uap, mask), size);
    742 	kcpuset_unuse(kcset, NULL);
    743 	*retval = size;
    744 	return error;
    745 }
    746 
    747 int
    748 linux_sys_sched_setaffinity(struct lwp *l, const struct linux_sys_sched_setaffinity_args *uap, register_t *retval)
    749 {
    750 	/* {
    751 		syscallarg(linux_pid_t) pid;
    752 		syscallarg(unsigned int) len;
    753 		syscallarg(unsigned long *) mask;
    754 	} */
    755 	struct sys__sched_setaffinity_args ssa;
    756 	size_t size;
    757 	pid_t pid;
    758 	lwpid_t lid;
    759 
    760 	size = LINUX_CPU_MASK_SIZE;
    761 	if (SCARG(uap, len) < size)
    762 		return EINVAL;
    763 
    764 	lid = SCARG(uap, pid);
    765 	if (lid != 0) {
    766 		/* Get the canonical PID for the process. */
    767 		mutex_enter(&proc_lock);
    768 		struct proc *p = proc_find_lwpid(SCARG(uap, pid));
    769 		if (p == NULL) {
    770 			mutex_exit(&proc_lock);
    771 			return ESRCH;
    772 		}
    773 		pid = p->p_pid;
    774 		mutex_exit(&proc_lock);
    775 	} else {
    776 		pid = curproc->p_pid;
    777 		lid = curlwp->l_lid;
    778 	}
    779 
    780 	SCARG(&ssa, pid) = pid;
    781 	SCARG(&ssa, lid) = lid;
    782 	SCARG(&ssa, size) = size;
    783 	SCARG(&ssa, cpuset) = (cpuset_t *)SCARG(uap, mask);
    784 
    785 	return sys__sched_setaffinity(l, &ssa, retval);
    786 }
    787 
    788 int
    789 linux_sys___prctl(struct lwp *l, const struct linux_sys___prctl_args *uap,
    790     register_t *retval)
    791 {
    792 	/* {
    793 		syscallarg(int)    code;
    794 		syscallarg(void *) args[LINUX_SYS_MAXSYSARGS];
    795 	} */
    796 
    797 	unsigned int c = SCARG(uap, code);
    798 
    799         /* TODO: add other commonly used prctl codes */
    800 	switch(c) {
    801 	case LINUX_PR_SET_NAME: {
    802 		struct sys__lwp_setname_args sls;
    803 		SCARG(&sls, name) = (char *) SCARG(uap, args[0]);
    804 		return sys__lwp_setname(l, &sls, retval);
    805 	}
    806 
    807 	case LINUX_PR_GET_NAME: {
    808 		struct sys__lwp_getname_args slg;
    809 		SCARG(&slg, name) = (char *) SCARG(uap, args[0]);
    810 		SCARG(&slg, len) = MAXCOMLEN;
    811 		return sys__lwp_getname(l, &slg, retval);
    812 		}
    813 	default:
    814 		printf("Unimplemented linux prctl code: (%d)", c);
    815 		return ENOSYS;
    816 	}
    817 
    818 }
    819