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      1 /* $NetBSD: cpu.c,v 1.84 2023/10/04 20:28:06 ad Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2007 Jared D. McNeill <jmcneill (at) invisible.ca>
      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 #include "opt_cpu.h"
     30 #include "opt_hz.h"
     31 
     32 #include <sys/cdefs.h>
     33 __KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.84 2023/10/04 20:28:06 ad Exp $");
     34 
     35 #include <sys/param.h>
     36 #include <sys/conf.h>
     37 #include <sys/proc.h>
     38 #include <sys/systm.h>
     39 #include <sys/device.h>
     40 #include <sys/reboot.h>
     41 #include <sys/lwp.h>
     42 #include <sys/cpu.h>
     43 #include <sys/mbuf.h>
     44 #include <sys/msgbuf.h>
     45 #include <sys/kmem.h>
     46 #include <sys/kernel.h>
     47 #include <sys/mount.h>
     48 
     49 #include <dev/cons.h>
     50 
     51 #include <machine/cpu.h>
     52 #include <machine/mainbus.h>
     53 #include <machine/pcb.h>
     54 #include <machine/machdep.h>
     55 #include <machine/thunk.h>
     56 
     57 #include <uvm/uvm_extern.h>
     58 #include <uvm/uvm_page.h>
     59 
     60 #if __GNUC_PREREQ__(4,4)
     61 #define cpu_unreachable()	__builtin_unreachable()
     62 #else
     63 #define cpu_unreachable()	do { thunk_abort(); } while (0)
     64 #endif
     65 
     66 static int	cpu_match(device_t, cfdata_t, void *);
     67 static void	cpu_attach(device_t, device_t, void *);
     68 
     69 /* XXX */
     70 //extern void *_lwp_getprivate(void);
     71 //extern int _lwp_setprivate(void *);
     72 
     73 
     74 struct cpu_info cpu_info_primary = {
     75 	.ci_dev = 0,
     76 	.ci_self = &cpu_info_primary,
     77 	.ci_idepth = -1,
     78 	.ci_curlwp = &lwp0,
     79 };
     80 
     81 typedef struct cpu_softc {
     82 	device_t	sc_dev;
     83 	struct cpu_info	*sc_ci;
     84 
     85 	ucontext_t	sc_ucp;
     86 	uint8_t		sc_ucp_stack[PAGE_SIZE];
     87 } cpu_softc_t;
     88 
     89 
     90 /* statics */
     91 static struct pcb lwp0pcb;
     92 static void *um_msgbuf;
     93 
     94 
     95 /* attachment */
     96 CFATTACH_DECL_NEW(cpu, sizeof(cpu_softc_t), cpu_match, cpu_attach, NULL, NULL);
     97 
     98 static int
     99 cpu_match(device_t parent, cfdata_t match, void *opaque)
    100 {
    101 	struct thunkbus_attach_args *taa = opaque;
    102 
    103 	if (taa->taa_type != THUNKBUS_TYPE_CPU)
    104 		return 0;
    105 
    106 	return 1;
    107 }
    108 
    109 static void
    110 cpu_attach(device_t parent, device_t self, void *opaque)
    111 {
    112 	cpu_softc_t *sc = device_private(self);
    113 
    114 	aprint_naive("\n");
    115 	aprint_normal("\n");
    116 
    117 	cpu_info_primary.ci_dev = self;
    118 	sc->sc_dev = self;
    119 	sc->sc_ci = &cpu_info_primary;
    120 
    121 	thunk_getcontext(&sc->sc_ucp);
    122 	sc->sc_ucp.uc_stack.ss_sp = sc->sc_ucp_stack;
    123 	sc->sc_ucp.uc_stack.ss_size = PAGE_SIZE - sizeof(register_t);
    124 	sc->sc_ucp.uc_flags = _UC_STACK | _UC_CPU | _UC_SIGMASK;
    125 	thunk_sigaddset(&sc->sc_ucp.uc_sigmask, SIGALRM);
    126 	thunk_sigaddset(&sc->sc_ucp.uc_sigmask, SIGIO);
    127 	thunk_sigaddset(&sc->sc_ucp.uc_sigmask, SIGINT);
    128 	thunk_sigaddset(&sc->sc_ucp.uc_sigmask, SIGTSTP);
    129 }
    130 
    131 void
    132 cpu_configure(void)
    133 {
    134 	cpu_setmodel("virtual processor");
    135 	if (config_rootfound("mainbus", NULL) == NULL)
    136 		panic("configure: mainbus not configured");
    137 
    138 	spl0();
    139 }
    140 
    141 
    142 /* main guts */
    143 void
    144 cpu_reboot(int howto, char *bootstr)
    145 {
    146 	extern void usermode_reboot(void);
    147 
    148 	if (cold)
    149 		howto |= RB_HALT;
    150 
    151 	if ((howto & RB_NOSYNC) == 0)
    152 		vfs_shutdown();
    153 	else
    154 		suspendsched();
    155 
    156 	doshutdownhooks();
    157 	pmf_system_shutdown(boothowto);
    158 
    159 	if ((howto & RB_POWERDOWN) == RB_POWERDOWN)
    160 		thunk_exit(0);
    161 
    162 	splhigh();
    163 
    164 	if (howto & RB_DUMP)
    165 		thunk_abort();
    166 
    167 	if (howto & RB_HALT) {
    168 		printf("\n");
    169 		printf("The operating system has halted.\n");
    170 		printf("Please press any key to reboot.\n\n");
    171 		cnpollc(1);
    172 		cngetc();
    173 		cnpollc(0);
    174 	}
    175 
    176 	printf("rebooting...\n");
    177 
    178 	usermode_reboot();
    179 
    180 	/* NOTREACHED */
    181 	cpu_unreachable();
    182 }
    183 
    184 void
    185 cpu_need_resched(struct cpu_info *ci, struct lwp *l, int flags)
    186 {
    187 	aston(ci);
    188 }
    189 
    190 void
    191 cpu_need_proftick(struct lwp *l)
    192 {
    193 }
    194 
    195 int
    196 cpu_lwp_setprivate(lwp_t *l, void *ptr)
    197 {
    198 	struct pcb *pcb = lwp_getpcb(l);
    199 
    200 	/* set both ucontexts up for TLS just in case */
    201 	pcb->pcb_ucp.uc_mcontext._mc_tlsbase =
    202 		(uintptr_t) ptr;
    203 	pcb->pcb_ucp.uc_flags |= _UC_TLSBASE;
    204 
    205 	pcb->pcb_userret_ucp.uc_mcontext._mc_tlsbase =
    206 		(uintptr_t) ptr;
    207 	pcb->pcb_userret_ucp.uc_flags |= _UC_TLSBASE;
    208 
    209 	return 0;
    210 }
    211 
    212 static
    213 void
    214 cpu_switchto_atomic(lwp_t *oldlwp, lwp_t *newlwp)
    215 {
    216 	struct pcb *oldpcb;
    217 	struct pcb *newpcb;
    218 	struct cpu_info *ci;
    219 	int s;
    220 
    221 	oldpcb = oldlwp ? lwp_getpcb(oldlwp) : NULL;
    222 	newpcb = lwp_getpcb(newlwp);
    223 	ci = curcpu();
    224 
    225 	s = splhigh();
    226 
    227 	ci->ci_stash = oldlwp;
    228 	if (oldpcb)
    229 		oldpcb->pcb_errno = thunk_geterrno();
    230 
    231 	thunk_seterrno(newpcb->pcb_errno);
    232 	curlwp = newlwp;
    233 
    234 	splx(s);
    235 
    236 	if (thunk_setcontext(&newpcb->pcb_ucp))
    237 		panic("setcontext failed");
    238 
    239 	/* not reached */
    240 }
    241 
    242 
    243 lwp_t *
    244 cpu_switchto(lwp_t *oldlwp, lwp_t *newlwp, bool returning)
    245 {
    246 	struct pcb *oldpcb = oldlwp ? lwp_getpcb(oldlwp) : NULL;
    247 	struct pcb *newpcb = lwp_getpcb(newlwp);
    248 	struct cpu_info *ci = curcpu();
    249 	cpu_softc_t *sc = device_private(ci->ci_dev);
    250 
    251 #ifdef CPU_DEBUG
    252 	thunk_printf_debug("cpu_switchto [%s,pid=%d,lid=%d] -> [%s,pid=%d,lid=%d]\n",
    253 	    oldlwp ? oldlwp->l_name : "none",
    254 	    oldlwp ? oldlwp->l_proc->p_pid : -1,
    255 	    oldlwp ? oldlwp->l_lid : -1,
    256 	    newlwp ? newlwp->l_name : "none",
    257 	    newlwp ? newlwp->l_proc->p_pid : -1,
    258 	    newlwp ? newlwp->l_lid : -1);
    259 	if (oldpcb) {
    260 		thunk_printf_debug("    oldpcb uc_link=%p, uc_stack.ss_sp=%p, "
    261 		    "uc_stack.ss_size=%d, l_private %p, uc_mcontext._mc_tlsbase=%p(%s)\n",
    262 		    oldpcb->pcb_ucp.uc_link,
    263 		    oldpcb->pcb_ucp.uc_stack.ss_sp,
    264 		    (int)oldpcb->pcb_ucp.uc_stack.ss_size,
    265 		    (void *) oldlwp->l_private,
    266 		    (void *) oldpcb->pcb_ucp.uc_mcontext._mc_tlsbase,
    267 		    oldpcb->pcb_ucp.uc_flags & _UC_TLSBASE? "ON":"off");
    268 	}
    269 	if (newpcb) {
    270 		thunk_printf_debug("    newpewcb uc_link=%p, uc_stack.ss_sp=%p, "
    271 		    "uc_stack.ss_size=%d, l_private %p, uc_mcontext._mc_tlsbase=%p(%s)\n",
    272 		    newpcb->pcb_ucp.uc_link,
    273 		    newpcb->pcb_ucp.uc_stack.ss_sp,
    274 		    (int)newpcb->pcb_ucp.uc_stack.ss_size,
    275 		    (void *) newlwp->l_private,
    276 		    (void *) newpcb->pcb_ucp.uc_mcontext._mc_tlsbase,
    277 		    newpcb->pcb_ucp.uc_flags & _UC_TLSBASE? "ON":"off");
    278 	}
    279 #endif /* !CPU_DEBUG */
    280 
    281 	/* create atomic switcher */
    282 	KASSERT(newlwp);
    283 	thunk_makecontext(&sc->sc_ucp, (void (*)(void)) cpu_switchto_atomic,
    284 			2, oldlwp, newlwp, NULL, NULL);
    285 	KASSERT(sc);
    286 	if (oldpcb) {
    287 		thunk_swapcontext(&oldpcb->pcb_ucp, &sc->sc_ucp);
    288 		/* returns here */
    289 	} else {
    290 		thunk_setcontext(&sc->sc_ucp);
    291 		/* never returns */
    292 	}
    293 
    294 #ifdef CPU_DEBUG
    295 	thunk_printf_debug("cpu_switchto: returning %p (was %p)\n", ci->ci_stash, oldlwp);
    296 #endif
    297 	return ci->ci_stash;
    298 }
    299 
    300 void
    301 cpu_dumpconf(void)
    302 {
    303 #ifdef CPU_DEBUG
    304 	thunk_printf_debug("cpu_dumpconf\n");
    305 #endif
    306 }
    307 
    308 void
    309 cpu_signotify(struct lwp *l)
    310 {
    311 }
    312 
    313 void
    314 cpu_getmcontext(struct lwp *l, mcontext_t *mcp, unsigned int *flags)
    315 {
    316 	struct pcb *pcb = lwp_getpcb(l);
    317 	ucontext_t *ucp = &pcb->pcb_userret_ucp;
    318 
    319 #ifdef CPU_DEBUG
    320 	thunk_printf_debug("cpu_getmcontext\n");
    321 #endif
    322 	memcpy(mcp, &ucp->uc_mcontext, sizeof(mcontext_t));
    323 
    324 	/* report we have the CPU FPU and TLSBASE registers */
    325 	mcp->_mc_tlsbase = (uintptr_t) l->l_private;
    326 	*flags = _UC_CPU | _UC_FPU | _UC_TLSBASE;
    327 
    328 	return;
    329 }
    330 
    331 int
    332 cpu_mcontext_validate(struct lwp *l, const mcontext_t *mcp)
    333 {
    334 	/*
    335 	 * can we check here? or should that be done in the target
    336 	 * specific places?
    337 	 */
    338 	/* XXX NO CHECKING! XXX */
    339 #ifdef CPU_DEBUG
    340 	thunk_printf_debug("cpu_mcontext_validate\n");
    341 #endif
    342 	return 0;
    343 }
    344 
    345 int
    346 cpu_setmcontext(struct lwp *l, const mcontext_t *mcp, unsigned int flags)
    347 {
    348 	struct pcb *pcb = lwp_getpcb(l);
    349 	ucontext_t *ucp = &pcb->pcb_userret_ucp;
    350 
    351 #ifdef CPU_DEBUG
    352 	thunk_printf_debug("cpu_setmcontext\n");
    353 #endif
    354 	if ((flags & _UC_CPU) != 0)
    355 		memcpy(&ucp->uc_mcontext.__gregs, &mcp->__gregs, sizeof(__gregset_t));
    356 	if ((flags & _UC_FPU) != 0)
    357 		memcpy(&ucp->uc_mcontext.__fpregs, &mcp->__fpregs, sizeof(__fpregset_t));
    358 	if ((flags & _UC_TLSBASE) != 0)
    359 		lwp_setprivate(l, (void *) (uintptr_t) mcp->_mc_tlsbase);
    360 
    361 #if 0
    362 	/*
    363 	 * XXX we ignore the set and clear stack since signals are done
    364 	 * slightly differently.
    365 	 */
    366 thunk_printf("%s: flags %x\n", __func__, flags);
    367 	mutex_enter(l->l_proc->p_lock);
    368 	if (flags & _UC_SETSTACK)
    369 		l->l_sigstk.ss_flags |= SS_ONSTACK;
    370 	if (flags & _UC_CLRSTACK)
    371 		l->l_sigstk.ss_flags &= ~SS_ONSTACK;
    372 	mutex_exit(l->l_proc->p_lock);
    373 #endif
    374 
    375 	ucp->uc_flags |= (flags & (_UC_CPU | _UC_FPU | _UC_TLSBASE));
    376 
    377 	return 0;
    378 }
    379 
    380 void
    381 cpu_idle(void)
    382 {
    383 	struct cpu_info *ci = curcpu();
    384 
    385 	if (ci->ci_want_resched)
    386 		return;
    387 
    388 	thunk_idle();
    389 }
    390 
    391 void
    392 cpu_lwp_free(struct lwp *l, int proc)
    393 {
    394 #ifdef CPU_DEBUG
    395 	thunk_printf_debug("cpu_lwp_free (dummy)\n");
    396 #endif
    397 }
    398 
    399 void
    400 cpu_lwp_free2(struct lwp *l)
    401 {
    402 	struct pcb *pcb = lwp_getpcb(l);
    403 
    404 #ifdef CPU_DEBUG
    405 	thunk_printf_debug("cpu_lwp_free2\n");
    406 #endif
    407 
    408 	if (pcb == NULL)
    409 		return;
    410 	/* XXX nothing to do? */
    411 }
    412 
    413 static void
    414 cpu_lwp_trampoline(ucontext_t *ucp, void (*func)(void *), void *arg)
    415 {
    416 #ifdef CPU_DEBUG
    417 	thunk_printf_debug("cpu_lwp_trampoline called with func %p, arg %p\n", (void *) func, arg);
    418 #endif
    419 	/* init lwp */
    420 	lwp_startup(curcpu()->ci_stash, curlwp);
    421 
    422 	/* actual jump */
    423 	thunk_makecontext(ucp, (void (*)(void)) func, 1, arg, NULL, NULL, NULL);
    424 	thunk_setcontext(ucp);
    425 }
    426 
    427 void
    428 cpu_lwp_fork(struct lwp *l1, struct lwp *l2, void *stack, size_t stacksize,
    429     void (*func)(void *), void *arg)
    430 {
    431 	struct pcb *pcb1 = lwp_getpcb(l1);
    432 	struct pcb *pcb2 = lwp_getpcb(l2);
    433 
    434 #ifdef CPU_DEBUG
    435 	thunk_printf_debug("cpu_lwp_fork [%s/%p] -> [%s/%p] stack=%p stacksize=%d\n",
    436 	    l1 ? l1->l_name : "none", l1,
    437 	    l2 ? l2->l_name : "none", l2,
    438 	    stack, (int)stacksize);
    439 #endif
    440 	if (stack)
    441 		panic("%s: stack passed, can't handle\n", __func__);
    442 
    443 	/* copy the PCB and its switchframes from parent */
    444 	memcpy(pcb2, pcb1, sizeof(struct pcb));
    445 
    446 	/* refresh context, XXX needed? */
    447 	if (thunk_getcontext(&pcb2->pcb_ucp))
    448 		panic("getcontext failed");
    449 
    450 	/* set up for TLS */
    451 	pcb2->pcb_ucp.uc_mcontext._mc_tlsbase = (intptr_t) l2->l_private;
    452 	pcb2->pcb_ucp.uc_flags |= _UC_TLSBASE;
    453 
    454 	/* recalculate the system stack top */
    455 	pcb2->sys_stack_top = pcb2->sys_stack + TRAPSTACKSIZE;
    456 
    457 	/* get l2 its own stack */
    458 	pcb2->pcb_ucp.uc_stack.ss_sp = pcb2->sys_stack;
    459 	pcb2->pcb_ucp.uc_stack.ss_size = pcb2->sys_stack_top - pcb2->sys_stack;
    460 	pcb2->pcb_ucp.uc_link = &pcb2->pcb_userret_ucp;
    461 
    462 	thunk_sigemptyset(&pcb2->pcb_ucp.uc_sigmask);
    463 
    464 	thunk_makecontext(&pcb2->pcb_ucp,
    465 	    (void (*)(void)) cpu_lwp_trampoline,
    466 	    3, &pcb2->pcb_ucp, func, arg, NULL);
    467 }
    468 
    469 void
    470 cpu_initclocks(void)
    471 {
    472 	extern timer_t clock_timerid;
    473 
    474 	thunk_timer_start(clock_timerid, HZ);
    475 }
    476 
    477 void
    478 cpu_startup(void)
    479 {
    480 	vaddr_t minaddr, maxaddr;
    481 	size_t msgbufsize = 32 * 1024;
    482 
    483 	/* get ourself a message buffer */
    484 	um_msgbuf = kmem_zalloc(msgbufsize, KM_SLEEP);
    485 	initmsgbuf(um_msgbuf, msgbufsize);
    486 
    487 	/* allocate a submap for physio, 1Mb enough? */
    488 	minaddr = 0;
    489 	phys_map = uvm_km_suballoc(kernel_map, &minaddr, &maxaddr,
    490 				   1024 * 1024, 0, false, NULL);
    491 
    492 	/* say hi! */
    493 	banner();
    494 
    495 	/* init lwp0 */
    496 	memset(&lwp0pcb, 0, sizeof(lwp0pcb));
    497 	thunk_getcontext(&lwp0pcb.pcb_ucp);
    498 	thunk_sigemptyset(&lwp0pcb.pcb_ucp.uc_sigmask);
    499 	lwp0pcb.pcb_ucp.uc_flags = _UC_STACK | _UC_CPU | _UC_SIGMASK;
    500 
    501 	uvm_lwp_setuarea(&lwp0, (vaddr_t) &lwp0pcb);
    502 	memcpy(&lwp0pcb.pcb_userret_ucp, &lwp0pcb.pcb_ucp, sizeof(ucontext_t));
    503 
    504 	/* set stack top */
    505 	lwp0pcb.sys_stack_top = lwp0pcb.sys_stack + TRAPSTACKSIZE;
    506 }
    507 
    508 void
    509 cpu_rootconf(void)
    510 {
    511 	extern char *usermode_root_device;
    512 	device_t rdev;
    513 
    514 	if (usermode_root_device != NULL) {
    515 		rdev = device_find_by_xname(usermode_root_device);
    516 	} else {
    517 		rdev = device_find_by_xname("ld0");
    518 		if (rdev == NULL)
    519 			rdev = device_find_by_xname("md0");
    520 	}
    521 
    522 	aprint_normal("boot device: %s\n",
    523 	    rdev ? device_xname(rdev) : "<unknown>");
    524 	booted_device = rdev;
    525 	rootconf();
    526 }
    527 
    528 bool
    529 cpu_intr_p(void)
    530 {
    531 	int idepth;
    532 	long pctr;
    533 	lwp_t *l;
    534 
    535 	l = curlwp;
    536 	do {
    537 		pctr = lwp_pctr();
    538 		idepth = l->l_cpu->ci_idepth;
    539 	} while (__predict_false(pctr != lwp_pctr()));
    540 
    541 	return idepth >= 0;
    542 }
    543