1 /*- 2 * Copyright (c) 1982, 1986 The Regents of the University of California. 3 * Copyright (c) 1989, 1990 William Jolitz 4 * Copyright (c) 1994 John Dyson 5 * Copyright (c) 2008 The DragonFly Project. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * the Systems Programming Group of the University of Utah Computer 10 * Science Department, and William Jolitz. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Berkeley and its contributors. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * from: @(#)vm_machdep.c 7.3 (Berkeley) 5/13/91 41 * Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$ 42 * $FreeBSD: src/sys/i386/i386/vm_machdep.c,v 1.132.2.9 2003/01/25 19:02:23 dillon Exp $ 43 */ 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/malloc.h> 48 #include <sys/proc.h> 49 #include <sys/buf.h> 50 #include <sys/interrupt.h> 51 #include <sys/vnode.h> 52 #include <sys/vmmeter.h> 53 #include <sys/kernel.h> 54 #include <sys/sysctl.h> 55 #include <sys/unistd.h> 56 57 #include <machine/clock.h> 58 #include <machine/cpu.h> 59 #include <machine/md_var.h> 60 #include <machine/smp.h> 61 #include <machine/pcb.h> 62 #include <machine/pcb_ext.h> 63 #include <machine/segments.h> 64 #include <machine/globaldata.h> /* npxthread */ 65 66 #include <vm/vm.h> 67 #include <vm/vm_param.h> 68 #include <sys/lock.h> 69 #include <vm/vm_kern.h> 70 #include <vm/vm_page.h> 71 #include <vm/vm_map.h> 72 #include <vm/vm_extern.h> 73 74 #include <sys/thread2.h> 75 76 #include <bus/isa/isa.h> 77 78 char machine[] = MACHINE; 79 SYSCTL_STRING(_hw, HW_MACHINE, machine, CTLFLAG_RD, 80 machine, 0, "Machine class"); 81 82 /* 83 * Finish a fork operation, with lwp lp2 nearly set up. 84 * Copy and update the pcb, set up the stack so that the child 85 * ready to run and return to user mode. 86 */ 87 void 88 cpu_fork(struct lwp *lp1, struct lwp *lp2, int flags) 89 { 90 struct pcb *pcb2; 91 92 if ((flags & RFPROC) == 0) { 93 if ((flags & RFMEM) == 0) { 94 /* unshare user LDT */ 95 struct pcb *pcb1 = lp1->lwp_thread->td_pcb; 96 struct pcb_ldt *pcb_ldt = pcb1->pcb_ldt; 97 if (pcb_ldt && pcb_ldt->ldt_refcnt > 1) { 98 pcb_ldt = user_ldt_alloc(pcb1,pcb_ldt->ldt_len); 99 user_ldt_free(pcb1); 100 pcb1->pcb_ldt = pcb_ldt; 101 set_user_ldt(pcb1); 102 } 103 } 104 return; 105 } 106 107 /* Ensure that lp1's pcb is up to date. */ 108 if (mdcpu->gd_npxthread == lp1->lwp_thread) 109 npxsave(lp1->lwp_thread->td_savefpu); 110 111 /* 112 * Copy lp1's PCB. This really only applies to the 113 * debug registers and FP state, but its faster to just copy the 114 * whole thing. Because we only save the PCB at switchout time, 115 * the register state may not be current. 116 */ 117 pcb2 = lp2->lwp_thread->td_pcb; 118 *pcb2 = *lp1->lwp_thread->td_pcb; 119 120 /* 121 * Create a new fresh stack for the new process. 122 * Copy the trap frame for the return to user mode as if from a 123 * syscall. This copies the user mode register values. 124 * 125 * pcb_rsp must allocate an additional call-return pointer below 126 * the trap frame which will be restored by cpu_heavy_restore from 127 * PCB_RIP, and the thread's td_sp pointer must allocate an 128 * additonal two quadwords below the pcb_rsp call-return pointer to 129 * hold the LWKT restore function pointer and rflags. 130 * 131 * The LWKT restore function pointer must be set to cpu_heavy_restore, 132 * which is our standard heavy-weight process switch-in function. 133 * YYY eventually we should shortcut fork_return and fork_trampoline 134 * to use the LWKT restore function directly so we can get rid of 135 * all the extra crap we are setting up. 136 */ 137 lp2->lwp_md.md_regs = (struct trapframe *)pcb2 - 1; 138 bcopy(lp1->lwp_md.md_regs, lp2->lwp_md.md_regs, sizeof(*lp2->lwp_md.md_regs)); 139 140 /* 141 * Set registers for trampoline to user mode. Leave space for the 142 * return address on stack. These are the kernel mode register values. 143 */ 144 pcb2->pcb_unused01 = 0; 145 pcb2->pcb_rbx = (unsigned long)fork_return; /* fork_trampoline argument */ 146 pcb2->pcb_rbp = 0; 147 pcb2->pcb_rsp = (unsigned long)lp2->lwp_md.md_regs - sizeof(void *); 148 pcb2->pcb_r12 = (unsigned long)lp2; /* fork_trampoline argument */ 149 pcb2->pcb_r13 = 0; 150 pcb2->pcb_r14 = 0; 151 pcb2->pcb_r15 = 0; 152 pcb2->pcb_rip = (unsigned long)fork_trampoline; 153 lp2->lwp_thread->td_sp = (char *)(pcb2->pcb_rsp - sizeof(void *)); 154 *(u_int64_t *)lp2->lwp_thread->td_sp = PSL_USER; 155 lp2->lwp_thread->td_sp -= sizeof(void *); 156 *(void **)lp2->lwp_thread->td_sp = (void *)cpu_heavy_restore; 157 158 /* 159 * pcb2->pcb_ldt: duplicated below, if necessary. 160 * pcb2->pcb_savefpu: cloned above. 161 * pcb2->pcb_flags: cloned above (always 0 here?). 162 * pcb2->pcb_onfault: cloned above (always NULL here?). 163 */ 164 165 /* 166 * XXX don't copy the i/o pages. this should probably be fixed. 167 */ 168 pcb2->pcb_ext = NULL; 169 170 /* Copy the LDT, if necessary. */ 171 if (pcb2->pcb_ldt != NULL) { 172 if (flags & RFMEM) { 173 pcb2->pcb_ldt->ldt_refcnt++; 174 } else { 175 pcb2->pcb_ldt = user_ldt_alloc(pcb2, 176 pcb2->pcb_ldt->ldt_len); 177 } 178 } 179 bcopy(&lp1->lwp_thread->td_tls, &lp2->lwp_thread->td_tls, 180 sizeof(lp2->lwp_thread->td_tls)); 181 /* 182 * Now, cpu_switch() can schedule the new lwp. 183 * pcb_rsp is loaded pointing to the cpu_switch() stack frame 184 * containing the return address when exiting cpu_switch. 185 * This will normally be to fork_trampoline(), which will have 186 * %rbx loaded with the new lwp's pointer. fork_trampoline() 187 * will set up a stack to call fork_return(lp, frame); to complete 188 * the return to user-mode. 189 */ 190 } 191 192 /* 193 * Prepare new lwp to return to the address specified in params. 194 */ 195 int 196 cpu_prepare_lwp(struct lwp *lp, struct lwp_params *params) 197 { 198 struct trapframe *regs = lp->lwp_md.md_regs; 199 void *bad_return = NULL; 200 int error; 201 202 regs->tf_rip = (long)params->func; 203 regs->tf_rsp = (long)params->stack; 204 /* Set up argument for function call */ 205 regs->tf_rdi = (long)params->arg; /* JG Can this be in userspace addresses? */ 206 /* 207 * Set up fake return address. As the lwp function may never return, 208 * we simply copy out a NULL pointer and force the lwp to receive 209 * a SIGSEGV if it returns anyways. 210 */ 211 regs->tf_rsp -= sizeof(void *); 212 error = copyout(&bad_return, (void *)regs->tf_rsp, sizeof(bad_return)); 213 if (error) 214 return (error); 215 216 cpu_set_fork_handler(lp, 217 (void (*)(void *, struct trapframe *))generic_lwp_return, lp); 218 return (0); 219 } 220 221 /* 222 * Intercept the return address from a freshly forked process that has NOT 223 * been scheduled yet. 224 * 225 * This is needed to make kernel threads stay in kernel mode. 226 */ 227 void 228 cpu_set_fork_handler(struct lwp *lp, void (*func)(void *, struct trapframe *), 229 void *arg) 230 { 231 /* 232 * Note that the trap frame follows the args, so the function 233 * is really called like this: func(arg, frame); 234 */ 235 lp->lwp_thread->td_pcb->pcb_rbx = (long)func; /* function */ 236 lp->lwp_thread->td_pcb->pcb_r12 = (long)arg; /* first arg */ 237 } 238 239 void 240 cpu_set_thread_handler(thread_t td, void (*rfunc)(void), void *func, void *arg) 241 { 242 td->td_pcb->pcb_rbx = (long)func; 243 td->td_pcb->pcb_r12 = (long)arg; 244 td->td_switch = cpu_lwkt_switch; 245 td->td_sp -= sizeof(void *); 246 *(void **)td->td_sp = rfunc; /* exit function on return */ 247 td->td_sp -= sizeof(void *); 248 *(void **)td->td_sp = cpu_kthread_restore; 249 } 250 251 void 252 cpu_lwp_exit(void) 253 { 254 struct thread *td = curthread; 255 struct pcb *pcb; 256 257 pcb = td->td_pcb; 258 259 /* Some i386 functionality was dropped */ 260 KKASSERT(pcb->pcb_ext == NULL); 261 262 /* 263 * disable all hardware breakpoints 264 */ 265 if (pcb->pcb_flags & PCB_DBREGS) { 266 reset_dbregs(); 267 pcb->pcb_flags &= ~PCB_DBREGS; 268 } 269 td->td_gd->gd_cnt.v_swtch++; 270 271 crit_enter_quick(td); 272 if (td->td_flags & TDF_TSLEEPQ) 273 tsleep_remove(td); 274 lwkt_deschedule_self(td); 275 lwkt_remove_tdallq(td); 276 cpu_thread_exit(); 277 } 278 279 /* 280 * Terminate the current thread. The caller must have already acquired 281 * the thread's rwlock and placed it on a reap list or otherwise notified 282 * a reaper of its existance. We set a special assembly switch function which 283 * releases td_rwlock after it has cleaned up the MMU state and switched 284 * out the stack. 285 * 286 * Must be caller from a critical section and with the thread descheduled. 287 */ 288 void 289 cpu_thread_exit(void) 290 { 291 npxexit(); 292 curthread->td_switch = cpu_exit_switch; 293 curthread->td_flags |= TDF_EXITING; 294 lwkt_switch(); 295 panic("cpu_thread_exit: lwkt_switch() unexpectedly returned"); 296 } 297 298 int 299 grow_stack(struct proc *p, u_long sp) 300 { 301 int rv; 302 303 rv = vm_map_growstack (p, sp); 304 if (rv != KERN_SUCCESS) 305 return (0); 306 307 return (1); 308 } 309 310 /* 311 * Used by /dev/kmem to determine if we can safely read or write 312 * the requested KVA range. Some portions of kernel memory are 313 * not governed by our virtual page table. 314 */ 315 extern int64_t _end; 316 extern void _start(void); 317 318 int 319 kvm_access_check(vm_offset_t saddr, vm_offset_t eaddr, int prot) 320 { 321 vm_offset_t addr; 322 323 if (saddr >= trunc_page((vm_offset_t)&_start) && eaddr <= round_page((vm_offset_t)&_end)) 324 return 0; 325 if (saddr < KvaStart) 326 return EFAULT; 327 if (eaddr >= KvaEnd) 328 return EFAULT; 329 for (addr = saddr; addr < eaddr; addr += PAGE_SIZE) { 330 if (pmap_extract(&kernel_pmap, addr) == 0) 331 return EFAULT; 332 } 333 if (!kernacc((caddr_t)saddr, eaddr - saddr, prot)) 334 return EFAULT; 335 return 0; 336 } 337