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cpu.c revision 1.73 
      1 /* $NetBSD: cpu.c,v 1.73 2014/03/24 20:06:33 christos 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 1.73 2014/03/24 20:06:33 christos 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 struct cpu_info cpu_info_primary = {
     70 	.ci_dev = 0,
     71 	.ci_self = &cpu_info_primary,
     72 	.ci_idepth = -1,
     73 	.ci_curlwp = &lwp0,
     74 };
     75 
     76 typedef struct cpu_softc {
     77 	device_t	sc_dev;
     78 	struct cpu_info	*sc_ci;
     79 
     80 	ucontext_t	sc_ucp;
     81 	uint8_t		sc_ucp_stack[PAGE_SIZE];
     82 } cpu_softc_t;
     83 
     84 
     85 /* statics */
     86 static struct pcb lwp0pcb;
     87 static void *um_msgbuf;
     88 
     89 
     90 /* attachment */
     91 CFATTACH_DECL_NEW(cpu, sizeof(cpu_softc_t), cpu_match, cpu_attach, NULL, NULL);
     92 
     93 static int
     94 cpu_match(device_t parent, cfdata_t match, void *opaque)
     95 {
     96 	struct thunkbus_attach_args *taa = opaque;
     97 
     98 	if (taa->taa_type != THUNKBUS_TYPE_CPU)
     99 		return 0;
    100 
    101 	return 1;
    102 }
    103 
    104 static void
    105 cpu_attach(device_t parent, device_t self, void *opaque)
    106 {
    107 	cpu_softc_t *sc = device_private(self);
    108 
    109 	aprint_naive("\n");
    110 	aprint_normal("\n");
    111 
    112 	cpu_info_primary.ci_dev = self;
    113 	sc->sc_dev = self;
    114 	sc->sc_ci = &cpu_info_primary;
    115 
    116 	thunk_getcontext(&sc->sc_ucp);
    117 	sc->sc_ucp.uc_stack.ss_sp = sc->sc_ucp_stack;
    118 	sc->sc_ucp.uc_stack.ss_size = PAGE_SIZE - sizeof(register_t);
    119 	sc->sc_ucp.uc_flags = _UC_STACK | _UC_CPU | _UC_SIGMASK;
    120 	thunk_sigaddset(&sc->sc_ucp.uc_sigmask, SIGALRM);
    121 	thunk_sigaddset(&sc->sc_ucp.uc_sigmask, SIGIO);
    122 }
    123 
    124 void
    125 cpu_configure(void)
    126 {
    127 	cpu_setmodel("virtual processor");
    128 	if (config_rootfound("mainbus", NULL) == NULL)
    129 		panic("configure: mainbus not configured");
    130 
    131 
    132 	spl0();
    133 }
    134 
    135 
    136 /* main guts */
    137 void
    138 cpu_reboot(int howto, char *bootstr)
    139 {
    140 	extern void usermode_reboot(void);
    141 
    142 	if (cold)
    143 		howto |= RB_HALT;
    144 
    145 	if ((howto & RB_NOSYNC) == 0)
    146 		vfs_shutdown();
    147 	else
    148 		suspendsched();
    149 
    150 	doshutdownhooks();
    151 	pmf_system_shutdown(boothowto);
    152 
    153 	if ((howto & RB_POWERDOWN) == RB_POWERDOWN)
    154 		thunk_exit(0);
    155 
    156 	splhigh();
    157 
    158 	if (howto & RB_DUMP)
    159 		thunk_abort();
    160 
    161 	if (howto & RB_HALT) {
    162 		printf("\n");
    163 		printf("The operating system has halted.\n");
    164 		printf("Please press any key to reboot.\n\n");
    165 		cnpollc(1);
    166 		cngetc();
    167 		cnpollc(0);
    168 	}
    169 
    170 	printf("rebooting...\n");
    171 
    172 	usermode_reboot();
    173 
    174 	/* NOTREACHED */
    175 	cpu_unreachable();
    176 }
    177 
    178 void
    179 cpu_need_resched(struct cpu_info *ci, int flags)
    180 {
    181 	ci->ci_want_resched |= flags;
    182 	aston(ci);
    183 }
    184 
    185 void
    186 cpu_need_proftick(struct lwp *l)
    187 {
    188 }
    189 
    190 static
    191 void
    192 cpu_switchto_atomic(lwp_t *oldlwp, lwp_t *newlwp)
    193 {
    194 	struct pcb *oldpcb = oldlwp ? lwp_getpcb(oldlwp) : NULL;
    195 	struct pcb *newpcb = lwp_getpcb(newlwp);
    196 	struct cpu_info *ci = curcpu();
    197 
    198 	ci->ci_stash = oldlwp;
    199 
    200 	if (oldpcb)
    201 		oldpcb->pcb_errno = thunk_geterrno();
    202 
    203 	thunk_seterrno(newpcb->pcb_errno);
    204 
    205 	curlwp = newlwp;
    206 	if (thunk_setcontext(&newpcb->pcb_ucp))
    207 		panic("setcontext failed");
    208 	/* not reached */
    209 }
    210 
    211 lwp_t *
    212 cpu_switchto(lwp_t *oldlwp, lwp_t *newlwp, bool returning)
    213 {
    214 	struct pcb *oldpcb = oldlwp ? lwp_getpcb(oldlwp) : NULL;
    215 	struct pcb *newpcb = lwp_getpcb(newlwp);
    216 	struct cpu_info *ci = curcpu();
    217 	cpu_softc_t *sc = device_private(ci->ci_dev);
    218 
    219 #ifdef CPU_DEBUG
    220 	thunk_printf_debug("cpu_switchto [%s,pid=%d,lid=%d] -> [%s,pid=%d,lid=%d]\n",
    221 	    oldlwp ? oldlwp->l_name : "none",
    222 	    oldlwp ? oldlwp->l_proc->p_pid : -1,
    223 	    oldlwp ? oldlwp->l_lid : -1,
    224 	    newlwp ? newlwp->l_name : "none",
    225 	    newlwp ? newlwp->l_proc->p_pid : -1,
    226 	    newlwp ? newlwp->l_lid : -1);
    227 	if (oldpcb) {
    228 		thunk_printf_debug("    oldpcb uc_link=%p, uc_stack.ss_sp=%p, "
    229 		    "uc_stack.ss_size=%d\n",
    230 		    oldpcb->pcb_ucp.uc_link,
    231 		    oldpcb->pcb_ucp.uc_stack.ss_sp,
    232 		    (int)oldpcb->pcb_ucp.uc_stack.ss_size);
    233 	}
    234 	if (newpcb) {
    235 		thunk_printf_debug("    newpcb uc_link=%p, uc_stack.ss_sp=%p, "
    236 		    "uc_stack.ss_size=%d\n",
    237 		    newpcb->pcb_ucp.uc_link,
    238 		    newpcb->pcb_ucp.uc_stack.ss_sp,
    239 		    (int)newpcb->pcb_ucp.uc_stack.ss_size);
    240 	}
    241 #endif /* !CPU_DEBUG */
    242 
    243 	/* create atomic switcher */
    244 	thunk_makecontext(&sc->sc_ucp, (void (*)(void)) cpu_switchto_atomic,
    245 			2, oldlwp, newlwp, NULL, NULL);
    246 
    247 	KASSERT(sc);
    248 	if (oldpcb) {
    249 		thunk_swapcontext(&oldpcb->pcb_ucp, &sc->sc_ucp);
    250 		/* returns here */
    251 	} else {
    252 		thunk_setcontext(&sc->sc_ucp);
    253 		/* never returns */
    254 	}
    255 
    256 #ifdef CPU_DEBUG
    257 	thunk_printf_debug("cpu_switchto: returning %p (was %p)\n", ci->ci_stash, oldlwp);
    258 #endif
    259 	return ci->ci_stash;
    260 }
    261 
    262 void
    263 cpu_dumpconf(void)
    264 {
    265 #ifdef CPU_DEBUG
    266 	thunk_printf_debug("cpu_dumpconf\n");
    267 #endif
    268 }
    269 
    270 void
    271 cpu_signotify(struct lwp *l)
    272 {
    273 }
    274 
    275 void
    276 cpu_getmcontext(struct lwp *l, mcontext_t *mcp, unsigned int *flags)
    277 {
    278 	struct pcb *pcb = lwp_getpcb(l);
    279 	ucontext_t *ucp = &pcb->pcb_userret_ucp;
    280 
    281 #ifdef CPU_DEBUG
    282 	thunk_printf_debug("cpu_getmcontext\n");
    283 #endif
    284 	memcpy(mcp, &ucp->uc_mcontext, sizeof(mcontext_t));
    285 	return;
    286 }
    287 
    288 int
    289 cpu_mcontext_validate(struct lwp *l, const mcontext_t *mcp)
    290 {
    291 	/*
    292 	 * can we check here? or should that be done in the target
    293 	 * specific places?
    294 	 */
    295 	return 0;
    296 }
    297 
    298 int
    299 cpu_setmcontext(struct lwp *l, const mcontext_t *mcp, unsigned int flags)
    300 {
    301 	struct pcb *pcb = lwp_getpcb(l);
    302 	ucontext_t *ucp = &pcb->pcb_userret_ucp;
    303 
    304 #ifdef CPU_DEBUG
    305 	thunk_printf_debug("cpu_setmcontext\n");
    306 #endif
    307 	memcpy(&ucp->uc_mcontext, mcp, sizeof(mcontext_t));
    308 	return 0;
    309 }
    310 
    311 void
    312 cpu_idle(void)
    313 {
    314 	struct cpu_info *ci = curcpu();
    315 
    316 	if (ci->ci_want_resched)
    317 		return;
    318 
    319 	thunk_idle();
    320 }
    321 
    322 void
    323 cpu_lwp_free(struct lwp *l, int proc)
    324 {
    325 #ifdef CPU_DEBUG
    326 	thunk_printf_debug("cpu_lwp_free (dummy)\n");
    327 #endif
    328 }
    329 
    330 void
    331 cpu_lwp_free2(struct lwp *l)
    332 {
    333 	struct pcb *pcb = lwp_getpcb(l);
    334 
    335 #ifdef CPU_DEBUG
    336 	thunk_printf_debug("cpu_lwp_free2\n");
    337 #endif
    338 
    339 	if (pcb == NULL)
    340 		return;
    341 	/* XXX nothing to do? */
    342 }
    343 
    344 static void
    345 cpu_lwp_trampoline(ucontext_t *ucp, void (*func)(void *), void *arg)
    346 {
    347 #ifdef CPU_DEBUG
    348 	thunk_printf_debug("cpu_lwp_trampoline called with func %p, arg %p\n", (void *) func, arg);
    349 #endif
    350 	/* init lwp */
    351 	lwp_startup(curcpu()->ci_stash, curlwp);
    352 
    353 	/* actual jump */
    354 	thunk_makecontext(ucp, (void (*)(void)) func, 1, arg, NULL, NULL, NULL);
    355 	thunk_setcontext(ucp);
    356 }
    357 
    358 void
    359 cpu_lwp_fork(struct lwp *l1, struct lwp *l2, void *stack, size_t stacksize,
    360     void (*func)(void *), void *arg)
    361 {
    362 	struct pcb *pcb1 = lwp_getpcb(l1);
    363 	struct pcb *pcb2 = lwp_getpcb(l2);
    364 
    365 #ifdef CPU_DEBUG
    366 	thunk_printf_debug("cpu_lwp_fork [%s/%p] -> [%s/%p] stack=%p stacksize=%d\n",
    367 	    l1 ? l1->l_name : "none", l1,
    368 	    l2 ? l2->l_name : "none", l2,
    369 	    stack, (int)stacksize);
    370 #endif
    371 
    372 	if (stack)
    373 		panic("%s: stack passed, can't handle\n", __func__);
    374 
    375 	/* copy the PCB and its switchframes from parent */
    376 	memcpy(pcb2, pcb1, sizeof(struct pcb));
    377 
    378 	/* refresh context */
    379 	if (thunk_getcontext(&pcb2->pcb_ucp))
    380 		panic("getcontext failed");
    381 
    382 	/* recalculate the system stack top */
    383 	pcb2->sys_stack_top = pcb2->sys_stack + TRAPSTACKSIZE;
    384 
    385 	/* get l2 its own stack */
    386 	pcb2->pcb_ucp.uc_stack.ss_sp = pcb2->sys_stack;
    387 	pcb2->pcb_ucp.uc_stack.ss_size = pcb2->sys_stack_top - pcb2->sys_stack;
    388 	pcb2->pcb_ucp.uc_link = &pcb2->pcb_userret_ucp;
    389 
    390 	thunk_sigemptyset(&pcb2->pcb_ucp.uc_sigmask);
    391 	pcb2->pcb_ucp.uc_flags = _UC_STACK | _UC_CPU | _UC_SIGMASK;
    392 	thunk_makecontext(&pcb2->pcb_ucp,
    393 	    (void (*)(void)) cpu_lwp_trampoline,
    394 	    3, &pcb2->pcb_ucp, func, arg, NULL);
    395 }
    396 
    397 void
    398 cpu_initclocks(void)
    399 {
    400 	extern timer_t clock_timerid;
    401 
    402 	thunk_timer_start(clock_timerid, HZ);
    403 }
    404 
    405 void
    406 cpu_startup(void)
    407 {
    408 	vaddr_t minaddr, maxaddr;
    409 	size_t msgbufsize = 32 * 1024;
    410 
    411 	/* get ourself a message buffer */
    412 	um_msgbuf = kmem_zalloc(msgbufsize, KM_SLEEP);
    413 	if (um_msgbuf == NULL)
    414 		panic("couldn't allocate msgbuf");
    415 	initmsgbuf(um_msgbuf, msgbufsize);
    416 
    417 	/* allocate a submap for physio, 1Mb enough? */
    418 	minaddr = 0;
    419 	phys_map = uvm_km_suballoc(kernel_map, &minaddr, &maxaddr,
    420 				   1024 * 1024, 0, false, NULL);
    421 
    422 	/* say hi! */
    423 	banner();
    424 
    425 	/* init lwp0 */
    426 	memset(&lwp0pcb, 0, sizeof(lwp0pcb));
    427 	thunk_getcontext(&lwp0pcb.pcb_ucp);
    428 	thunk_sigemptyset(&lwp0pcb.pcb_ucp.uc_sigmask);
    429 	lwp0pcb.pcb_ucp.uc_flags = _UC_STACK | _UC_CPU | _UC_SIGMASK;
    430 
    431 	uvm_lwp_setuarea(&lwp0, (vaddr_t) &lwp0pcb);
    432 	memcpy(&lwp0pcb.pcb_userret_ucp, &lwp0pcb.pcb_ucp, sizeof(ucontext_t));
    433 
    434 	/* set stack top */
    435 	lwp0pcb.sys_stack_top = lwp0pcb.sys_stack + TRAPSTACKSIZE;
    436 }
    437 
    438 void
    439 cpu_rootconf(void)
    440 {
    441 	extern char *usermode_root_device;
    442 	device_t rdev;
    443 
    444 	if (usermode_root_device != NULL) {
    445 		rdev = device_find_by_xname(usermode_root_device);
    446 	} else {
    447 		rdev = device_find_by_xname("ld0");
    448 		if (rdev == NULL)
    449 			rdev = device_find_by_xname("md0");
    450 	}
    451 
    452 	aprint_normal("boot device: %s\n",
    453 	    rdev ? device_xname(rdev) : "<unknown>");
    454 	booted_device = rdev;
    455 	rootconf();
    456 }
    457 
    458 bool
    459 cpu_intr_p(void)
    460 {
    461 	int idepth;
    462 
    463 	kpreempt_disable();
    464 	idepth = curcpu()->ci_idepth;
    465 	kpreempt_enable();
    466 
    467 	return (idepth >= 0);
    468 }
    469