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 * $DragonFly: src/sys/platform/pc64/amd64/vm_machdep.c,v 1.3 2008/08/29 17:07:10 dillon Exp $ 44 */ 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/malloc.h> 49 #include <sys/proc.h> 50 #include <sys/buf.h> 51 #include <sys/interrupt.h> 52 #include <sys/vnode.h> 53 #include <sys/vmmeter.h> 54 #include <sys/kernel.h> 55 #include <sys/sysctl.h> 56 #include <sys/unistd.h> 57 58 #include <machine/clock.h> 59 #include <machine/cpu.h> 60 #include <machine/md_var.h> 61 #include <machine/smp.h> 62 #include <machine/pcb.h> 63 #include <machine/pcb_ext.h> 64 #include <machine/segments.h> 65 #include <machine/globaldata.h> /* npxthread */ 66 67 #include <vm/vm.h> 68 #include <vm/vm_param.h> 69 #include <sys/lock.h> 70 #include <vm/vm_kern.h> 71 #include <vm/vm_page.h> 72 #include <vm/vm_map.h> 73 #include <vm/vm_extern.h> 74 75 #include <sys/thread2.h> 76 77 #include <bus/isa/isa.h> 78 79 char machine[] = MACHINE; 80 SYSCTL_STRING(_hw, HW_MACHINE, machine, CTLFLAG_RD, 81 machine, 0, "Machine class"); 82 83 /* 84 * Finish a fork operation, with lwp lp2 nearly set up. 85 * Copy and update the pcb, set up the stack so that the child 86 * ready to run and return to user mode. 87 */ 88 void 89 cpu_fork(struct lwp *lp1, struct lwp *lp2, int flags) 90 { 91 struct pcb *pcb2; 92 93 if ((flags & RFPROC) == 0) { 94 if ((flags & RFMEM) == 0) { 95 /* unshare user LDT */ 96 struct pcb *pcb1 = lp1->lwp_thread->td_pcb; 97 struct pcb_ldt *pcb_ldt = pcb1->pcb_ldt; 98 if (pcb_ldt && pcb_ldt->ldt_refcnt > 1) { 99 pcb_ldt = user_ldt_alloc(pcb1,pcb_ldt->ldt_len); 100 user_ldt_free(pcb1); 101 pcb1->pcb_ldt = pcb_ldt; 102 set_user_ldt(pcb1); 103 } 104 } 105 return; 106 } 107 108 /* Ensure that lp1's pcb is up to date. */ 109 if (mdcpu->gd_npxthread == lp1->lwp_thread) 110 npxsave(lp1->lwp_thread->td_savefpu); 111 112 /* 113 * Copy lp1's PCB. This really only applies to the 114 * debug registers and FP state, but its faster to just copy the 115 * whole thing. Because we only save the PCB at switchout time, 116 * the register state may not be current. 117 */ 118 pcb2 = lp2->lwp_thread->td_pcb; 119 *pcb2 = *lp1->lwp_thread->td_pcb; 120 121 /* 122 * Create a new fresh stack for the new process. 123 * Copy the trap frame for the return to user mode as if from a 124 * syscall. This copies the user mode register values. 125 * 126 * pcb_rsp must allocate an additional call-return pointer below 127 * the trap frame which will be restored by cpu_heavy_restore from 128 * PCB_RIP, and the thread's td_sp pointer must allocate an 129 * additonal two quadwords below the pcb_rsp call-return pointer to 130 * hold the LWKT restore function pointer and rflags. 131 * 132 * The LWKT restore function pointer must be set to cpu_heavy_restore, 133 * which is our standard heavy-weight process switch-in function. 134 * YYY eventually we should shortcut fork_return and fork_trampoline 135 * to use the LWKT restore function directly so we can get rid of 136 * all the extra crap we are setting up. 137 */ 138 lp2->lwp_md.md_regs = (struct trapframe *)pcb2 - 1; 139 bcopy(lp1->lwp_md.md_regs, lp2->lwp_md.md_regs, sizeof(*lp2->lwp_md.md_regs)); 140 141 /* 142 * Set registers for trampoline to user mode. Leave space for the 143 * return address on stack. These are the kernel mode register values. 144 */ 145 pcb2->pcb_unused01 = 0; 146 pcb2->pcb_rbx = (unsigned long)fork_return; /* fork_trampoline argument */ 147 pcb2->pcb_rbp = 0; 148 pcb2->pcb_rsp = (unsigned long)lp2->lwp_md.md_regs - sizeof(void *); 149 pcb2->pcb_r12 = (unsigned long)lp2; /* fork_trampoline argument */ 150 pcb2->pcb_r13 = 0; 151 pcb2->pcb_r14 = 0; 152 pcb2->pcb_r15 = 0; 153 pcb2->pcb_rip = (unsigned long)fork_trampoline; 154 lp2->lwp_thread->td_sp = (char *)(pcb2->pcb_rsp - sizeof(void *)); 155 *(u_int64_t *)lp2->lwp_thread->td_sp = PSL_USER; 156 lp2->lwp_thread->td_sp -= sizeof(void *); 157 *(void **)lp2->lwp_thread->td_sp = (void *)cpu_heavy_restore; 158 159 /* 160 * pcb2->pcb_ldt: duplicated below, if necessary. 161 * pcb2->pcb_savefpu: cloned above. 162 * pcb2->pcb_flags: cloned above (always 0 here?). 163 * pcb2->pcb_onfault: cloned above (always NULL here?). 164 */ 165 166 /* 167 * XXX don't copy the i/o pages. this should probably be fixed. 168 */ 169 pcb2->pcb_ext = 0; 170 171 /* Copy the LDT, if necessary. */ 172 if (pcb2->pcb_ldt != 0) { 173 if (flags & RFMEM) { 174 pcb2->pcb_ldt->ldt_refcnt++; 175 } else { 176 pcb2->pcb_ldt = user_ldt_alloc(pcb2, 177 pcb2->pcb_ldt->ldt_len); 178 } 179 } 180 bcopy(&lp1->lwp_thread->td_tls, &lp2->lwp_thread->td_tls, 181 sizeof(lp2->lwp_thread->td_tls)); 182 /* 183 * Now, cpu_switch() can schedule the new lwp. 184 * pcb_rsp is loaded pointing to the cpu_switch() stack frame 185 * containing the return address when exiting cpu_switch. 186 * This will normally be to fork_trampoline(), which will have 187 * %rbx loaded with the new lwp's pointer. fork_trampoline() 188 * will set up a stack to call fork_return(lp, frame); to complete 189 * the return to user-mode. 190 */ 191 } 192 193 /* 194 * Prepare new lwp to return to the address specified in params. 195 */ 196 int 197 cpu_prepare_lwp(struct lwp *lp, struct lwp_params *params) 198 { 199 struct trapframe *regs = lp->lwp_md.md_regs; 200 void *bad_return = NULL; 201 int error; 202 203 regs->tf_rip = (long)params->func; 204 regs->tf_rsp = (long)params->stack; 205 /* Set up argument for function call */ 206 regs->tf_rdi = (long)params->arg; /* JG Can this be in userspace addresses? */ 207 /* 208 * Set up fake return address. As the lwp function may never return, 209 * we simply copy out a NULL pointer and force the lwp to receive 210 * a SIGSEGV if it returns anyways. 211 */ 212 regs->tf_rsp -= sizeof(void *); 213 error = copyout(&bad_return, (void *)regs->tf_rsp, sizeof(bad_return)); 214 if (error) 215 return (error); 216 217 cpu_set_fork_handler(lp, 218 (void (*)(void *, struct trapframe *))generic_lwp_return, lp); 219 return (0); 220 } 221 222 /* 223 * Intercept the return address from a freshly forked process that has NOT 224 * been scheduled yet. 225 * 226 * This is needed to make kernel threads stay in kernel mode. 227 */ 228 void 229 cpu_set_fork_handler(struct lwp *lp, void (*func)(void *, struct trapframe *), 230 void *arg) 231 { 232 /* 233 * Note that the trap frame follows the args, so the function 234 * is really called like this: func(arg, frame); 235 */ 236 lp->lwp_thread->td_pcb->pcb_rbx = (long)func; /* function */ 237 lp->lwp_thread->td_pcb->pcb_r12 = (long)arg; /* first arg */ 238 } 239 240 void 241 cpu_set_thread_handler(thread_t td, void (*rfunc)(void), void *func, void *arg) 242 { 243 td->td_pcb->pcb_rbx = (long)func; 244 td->td_pcb->pcb_r12 = (long)arg; 245 td->td_switch = cpu_lwkt_switch; 246 td->td_sp -= sizeof(void *); 247 *(void **)td->td_sp = rfunc; /* exit function on return */ 248 td->td_sp -= sizeof(void *); 249 *(void **)td->td_sp = cpu_kthread_restore; 250 } 251 252 void 253 cpu_lwp_exit(void) 254 { 255 struct thread *td = curthread; 256 struct pcb *pcb; 257 npxexit(); 258 pcb = td->td_pcb; 259 KKASSERT(pcb->pcb_ext == NULL); /* Some i386 functionality was dropped */ 260 if (pcb->pcb_flags & PCB_DBREGS) { 261 /* 262 * disable all hardware breakpoints 263 */ 264 reset_dbregs(); 265 pcb->pcb_flags &= ~PCB_DBREGS; 266 } 267 td->td_gd->gd_cnt.v_swtch++; 268 269 crit_enter_quick(td); 270 lwkt_deschedule_self(td); 271 lwkt_remove_tdallq(td); 272 cpu_thread_exit(); 273 } 274 275 /* 276 * Terminate the current thread. The caller must have already acquired 277 * the thread's rwlock and placed it on a reap list or otherwise notified 278 * a reaper of its existance. We set a special assembly switch function which 279 * releases td_rwlock after it has cleaned up the MMU state and switched 280 * out the stack. 281 * 282 * Must be caller from a critical section and with the thread descheduled. 283 */ 284 void 285 cpu_thread_exit(void) 286 { 287 curthread->td_switch = cpu_exit_switch; 288 curthread->td_flags |= TDF_EXITING; 289 lwkt_switch(); 290 panic("cpu_thread_exit: lwkt_switch() unexpectedly returned"); 291 } 292 293 /* 294 * Process Reaper. Called after the caller has acquired the thread's 295 * rwlock and removed it from the reap list. 296 */ 297 void 298 cpu_proc_wait(struct proc *p) 299 { 300 /* drop per-process resources */ 301 pmap_dispose_proc(p); 302 } 303 304 int 305 grow_stack(struct proc *p, u_long sp) 306 { 307 int rv; 308 309 rv = vm_map_growstack (p, sp); 310 if (rv != KERN_SUCCESS) 311 return (0); 312 313 return (1); 314 } 315 316 /* 317 * Tell whether this address is in some physical memory region. 318 * Currently used by the kernel coredump code in order to avoid 319 * dumping the ``ISA memory hole'' which could cause indefinite hangs, 320 * or other unpredictable behaviour. 321 */ 322 323 int 324 is_physical_memory(vm_offset_t addr) 325 { 326 return 1; 327 } 328 329 /* 330 * Used by /dev/kmem to determine if we can safely read or write 331 * the requested KVA range. Some portions of kernel memory are 332 * not governed by our virtual page table. 333 */ 334 extern int64_t _end; 335 extern void _start(void); 336 337 int 338 kvm_access_check(vm_offset_t saddr, vm_offset_t eaddr, int prot) 339 { 340 vm_offset_t addr; 341 342 if (saddr >= trunc_page((vm_offset_t)&_start) && eaddr <= round_page((vm_offset_t)&_end)) 343 return 0; 344 if (saddr < KvaStart) 345 return EFAULT; 346 if (eaddr >= KvaEnd) 347 return EFAULT; 348 for (addr = saddr; addr < eaddr; addr += PAGE_SIZE) { 349 if (pmap_extract(&kernel_pmap, addr) == 0) 350 return EFAULT; 351 } 352 if (!kernacc((caddr_t)saddr, eaddr - saddr, prot)) 353 return EFAULT; 354 return 0; 355 } 356