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cpu.c revision 1.70 
      1 /* $NetBSD: cpu.c,v 1.70 2012/03/03 21:15:15 reinoud 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 1.70 2012/03/03 21:15:15 reinoud 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 char cpu_model[48] = "virtual processor";
     77 
     78 typedef struct cpu_softc {
     79 	device_t	sc_dev;
     80 	struct cpu_info	*sc_ci;
     81 
     82 	ucontext_t	sc_ucp;
     83 	uint8_t		sc_ucp_stack[PAGE_SIZE];
     84 } cpu_softc_t;
     85 
     86 
     87 /* statics */
     88 static struct pcb lwp0pcb;
     89 static void *um_msgbuf;
     90 
     91 
     92 /* attachment */
     93 CFATTACH_DECL_NEW(cpu, sizeof(cpu_softc_t), cpu_match, cpu_attach, NULL, NULL);
     94 
     95 static int
     96 cpu_match(device_t parent, cfdata_t match, void *opaque)
     97 {
     98 	struct thunkbus_attach_args *taa = opaque;
     99 
    100 	if (taa->taa_type != THUNKBUS_TYPE_CPU)
    101 		return 0;
    102 
    103 	return 1;
    104 }
    105 
    106 static void
    107 cpu_attach(device_t parent, device_t self, void *opaque)
    108 {
    109 	cpu_softc_t *sc = device_private(self);
    110 
    111 	aprint_naive("\n");
    112 	aprint_normal("\n");
    113 
    114 	cpu_info_primary.ci_dev = self;
    115 	sc->sc_dev = self;
    116 	sc->sc_ci = &cpu_info_primary;
    117 
    118 	thunk_getcontext(&sc->sc_ucp);
    119 	sc->sc_ucp.uc_stack.ss_sp = sc->sc_ucp_stack;
    120 	sc->sc_ucp.uc_stack.ss_size = PAGE_SIZE - sizeof(register_t);
    121 	sc->sc_ucp.uc_flags = _UC_STACK | _UC_CPU | _UC_SIGMASK;
    122 	thunk_sigaddset(&sc->sc_ucp.uc_sigmask, SIGALRM);
    123 	thunk_sigaddset(&sc->sc_ucp.uc_sigmask, SIGIO);
    124 }
    125 
    126 void
    127 cpu_configure(void)
    128 {
    129 	if (config_rootfound("mainbus", NULL) == NULL)
    130 		panic("configure: mainbus not configured");
    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_setmcontext(struct lwp *l, const mcontext_t *mcp, unsigned int flags)
    290 {
    291 	struct pcb *pcb = lwp_getpcb(l);
    292 	ucontext_t *ucp = &pcb->pcb_userret_ucp;
    293 
    294 #ifdef CPU_DEBUG
    295 	thunk_printf_debug("cpu_setmcontext\n");
    296 #endif
    297 	memcpy(&ucp->uc_mcontext, mcp, sizeof(mcontext_t));
    298 	return 0;
    299 }
    300 
    301 void
    302 cpu_idle(void)
    303 {
    304 	struct cpu_info *ci = curcpu();
    305 
    306 	if (ci->ci_want_resched)
    307 		return;
    308 
    309 	thunk_idle();
    310 }
    311 
    312 void
    313 cpu_lwp_free(struct lwp *l, int proc)
    314 {
    315 #ifdef CPU_DEBUG
    316 	thunk_printf_debug("cpu_lwp_free (dummy)\n");
    317 #endif
    318 }
    319 
    320 void
    321 cpu_lwp_free2(struct lwp *l)
    322 {
    323 	struct pcb *pcb = lwp_getpcb(l);
    324 
    325 #ifdef CPU_DEBUG
    326 	thunk_printf_debug("cpu_lwp_free2\n");
    327 #endif
    328 
    329 	if (pcb == NULL)
    330 		return;
    331 	/* XXX nothing to do? */
    332 }
    333 
    334 static void
    335 cpu_lwp_trampoline(ucontext_t *ucp, void (*func)(void *), void *arg)
    336 {
    337 #ifdef CPU_DEBUG
    338 	thunk_printf_debug("cpu_lwp_trampoline called with func %p, arg %p\n", (void *) func, arg);
    339 #endif
    340 	/* init lwp */
    341 	lwp_startup(curcpu()->ci_stash, curlwp);
    342 
    343 	/* actual jump */
    344 	thunk_makecontext(ucp, (void (*)(void)) func, 1, arg, NULL, NULL, NULL);
    345 	thunk_setcontext(ucp);
    346 }
    347 
    348 void
    349 cpu_lwp_fork(struct lwp *l1, struct lwp *l2, void *stack, size_t stacksize,
    350     void (*func)(void *), void *arg)
    351 {
    352 	struct pcb *pcb1 = lwp_getpcb(l1);
    353 	struct pcb *pcb2 = lwp_getpcb(l2);
    354 
    355 #ifdef CPU_DEBUG
    356 	thunk_printf_debug("cpu_lwp_fork [%s/%p] -> [%s/%p] stack=%p stacksize=%d\n",
    357 	    l1 ? l1->l_name : "none", l1,
    358 	    l2 ? l2->l_name : "none", l2,
    359 	    stack, (int)stacksize);
    360 #endif
    361 
    362 	if (stack)
    363 		panic("%s: stack passed, can't handle\n", __func__);
    364 
    365 	/* copy the PCB and its switchframes from parent */
    366 	memcpy(pcb2, pcb1, sizeof(struct pcb));
    367 
    368 	/* refresh context */
    369 	if (thunk_getcontext(&pcb2->pcb_ucp))
    370 		panic("getcontext failed");
    371 
    372 	/* recalculate the system stack top */
    373 	pcb2->sys_stack_top = pcb2->sys_stack + TRAPSTACKSIZE;
    374 
    375 	/* get l2 its own stack */
    376 	pcb2->pcb_ucp.uc_stack.ss_sp = pcb2->sys_stack;
    377 	pcb2->pcb_ucp.uc_stack.ss_size = pcb2->sys_stack_top - pcb2->sys_stack;
    378 	pcb2->pcb_ucp.uc_link = &pcb2->pcb_userret_ucp;
    379 
    380 	thunk_sigemptyset(&pcb2->pcb_ucp.uc_sigmask);
    381 	pcb2->pcb_ucp.uc_flags = _UC_STACK | _UC_CPU | _UC_SIGMASK;
    382 	thunk_makecontext(&pcb2->pcb_ucp,
    383 	    (void (*)(void)) cpu_lwp_trampoline,
    384 	    3, &pcb2->pcb_ucp, func, arg, NULL);
    385 }
    386 
    387 void
    388 cpu_initclocks(void)
    389 {
    390 	extern timer_t clock_timerid;
    391 
    392 	thunk_timer_start(clock_timerid, HZ);
    393 }
    394 
    395 void
    396 cpu_startup(void)
    397 {
    398 	vaddr_t minaddr, maxaddr;
    399 	size_t msgbufsize = 32 * 1024;
    400 
    401 	/* get ourself a message buffer */
    402 	um_msgbuf = kmem_zalloc(msgbufsize, KM_SLEEP);
    403 	if (um_msgbuf == NULL)
    404 		panic("couldn't allocate msgbuf");
    405 	initmsgbuf(um_msgbuf, msgbufsize);
    406 
    407 	/* allocate a submap for physio, 1Mb enough? */
    408 	minaddr = 0;
    409 	phys_map = uvm_km_suballoc(kernel_map, &minaddr, &maxaddr,
    410 				   1024 * 1024, 0, false, NULL);
    411 
    412 	/* say hi! */
    413 	banner();
    414 
    415 	/* init lwp0 */
    416 	memset(&lwp0pcb, 0, sizeof(lwp0pcb));
    417 	thunk_getcontext(&lwp0pcb.pcb_ucp);
    418 	thunk_sigemptyset(&lwp0pcb.pcb_ucp.uc_sigmask);
    419 	lwp0pcb.pcb_ucp.uc_flags = _UC_STACK | _UC_CPU | _UC_SIGMASK;
    420 
    421 	uvm_lwp_setuarea(&lwp0, (vaddr_t) &lwp0pcb);
    422 	memcpy(&lwp0pcb.pcb_userret_ucp, &lwp0pcb.pcb_ucp, sizeof(ucontext_t));
    423 
    424 	/* set stack top */
    425 	lwp0pcb.sys_stack_top = lwp0pcb.sys_stack + TRAPSTACKSIZE;
    426 }
    427 
    428 void
    429 cpu_rootconf(void)
    430 {
    431 	extern char *usermode_root_device;
    432 	device_t rdev;
    433 
    434 	if (usermode_root_device != NULL) {
    435 		rdev = device_find_by_xname(usermode_root_device);
    436 	} else {
    437 		rdev = device_find_by_xname("ld0");
    438 		if (rdev == NULL)
    439 			rdev = device_find_by_xname("md0");
    440 	}
    441 
    442 	aprint_normal("boot device: %s\n",
    443 	    rdev ? device_xname(rdev) : "<unknown>");
    444 	setroot(rdev, 0);
    445 }
    446 
    447 bool
    448 cpu_intr_p(void)
    449 {
    450 	int idepth;
    451 
    452 	kpreempt_disable();
    453 	idepth = curcpu()->ci_idepth;
    454 	kpreempt_enable();
    455 
    456 	return (idepth >= 0);
    457 }
    458