/*- * Copyright (c) 1982, 1986 The Regents of the University of California. * Copyright (c) 1989, 1990 William Jolitz * Copyright (c) 1994 John Dyson * Copyright (c) 2008 The DragonFly Project. * All rights reserved. * * This code is derived from software contributed to Berkeley by * the Systems Programming Group of the University of Utah Computer * Science Department, and William Jolitz. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from: @(#)vm_machdep.c 7.3 (Berkeley) 5/13/91 * Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$ * $FreeBSD: src/sys/i386/i386/vm_machdep.c,v 1.132.2.9 2003/01/25 19:02:23 dillon Exp $ */ #include <sys/param.h> #include <sys/systm.h> #include <sys/malloc.h> #include <sys/proc.h> #include <sys/buf.h> #include <sys/interrupt.h> #include <sys/vnode.h> #include <sys/vmmeter.h> #include <sys/kernel.h> #include <sys/sysctl.h> #include <sys/unistd.h> #include <sys/lwp.h> #include <machine/clock.h> #include <machine/cpu.h> #include <machine/md_var.h> #include <machine/smp.h> #include <machine/pcb.h> #include <machine/pcb_ext.h> #include <machine/segments.h> #include <machine/globaldata.h> /* npxthread */ #include <vm/vm.h> #include <vm/vm_param.h> #include <sys/lock.h> #include <vm/vm_kern.h> #include <vm/vm_page.h> #include <vm/vm_map.h> #include <vm/vm_extern.h> #include <sys/thread2.h> #include <bus/isa/isa.h> char machine[] = MACHINE; SYSCTL_STRING(_hw, HW_MACHINE, machine, CTLFLAG_RD, machine, 0, "Machine class"); u_int cpu_vendor_id = 0; /* XXX */ /* * Finish a fork operation, with lwp lp2 nearly set up. * Copy and update the pcb, set up the stack so that the child * ready to run and return to user mode. */ void cpu_fork(struct lwp *lp1, struct lwp *lp2, int flags) { struct pcb *pcb2; if ((flags & RFPROC) == 0) { if ((flags & RFMEM) == 0) { /* unshare user LDT */ struct pcb *pcb1 = lp1->lwp_thread->td_pcb; struct pcb_ldt *pcb_ldt = pcb1->pcb_ldt; if (pcb_ldt && pcb_ldt->ldt_refcnt > 1) { pcb_ldt = user_ldt_alloc(pcb1,pcb_ldt->ldt_len); user_ldt_free(pcb1); pcb1->pcb_ldt = pcb_ldt; set_user_ldt(pcb1); } } return; } /* Ensure that lp1's pcb is up to date. */ if (mdcpu->gd_npxthread == lp1->lwp_thread) npxsave(lp1->lwp_thread->td_savefpu); /* * Copy lp1's PCB. This really only applies to the * debug registers and FP state, but its faster to just copy the * whole thing. Because we only save the PCB at switchout time, * the register state may not be current. */ pcb2 = lp2->lwp_thread->td_pcb; *pcb2 = *lp1->lwp_thread->td_pcb; /* * Create a new fresh stack for the new process. * Copy the trap frame for the return to user mode as if from a * syscall. This copies the user mode register values. * * pcb_rsp must allocate an additional call-return pointer below * the trap frame which will be restored by cpu_heavy_restore from * PCB_RIP, and the thread's td_sp pointer must allocate an * additonal two quadwords below the pcb_rsp call-return pointer to * hold the LWKT restore function pointer and rflags. * * The LWKT restore function pointer must be set to cpu_heavy_restore, * which is our standard heavy-weight process switch-in function. * YYY eventually we should shortcut fork_return and fork_trampoline * to use the LWKT restore function directly so we can get rid of * all the extra crap we are setting up. */ lp2->lwp_md.md_regs = (struct trapframe *)pcb2 - 1; bcopy(lp1->lwp_md.md_regs, lp2->lwp_md.md_regs, sizeof(*lp2->lwp_md.md_regs)); /* * Set registers for trampoline to user mode. Leave space for the * return address on stack. These are the kernel mode register values. */ pcb2->pcb_unused01 = 0; pcb2->pcb_rbx = (unsigned long)fork_return; /* fork_trampoline argument */ pcb2->pcb_rbp = 0; pcb2->pcb_rsp = (unsigned long)lp2->lwp_md.md_regs - sizeof(void *); pcb2->pcb_r12 = (unsigned long)lp2; /* fork_trampoline argument */ pcb2->pcb_r13 = 0; pcb2->pcb_r14 = 0; pcb2->pcb_r15 = 0; pcb2->pcb_rip = (unsigned long)fork_trampoline; lp2->lwp_thread->td_sp = (char *)(pcb2->pcb_rsp - sizeof(void *)); *(u_int64_t *)lp2->lwp_thread->td_sp = PSL_USER; lp2->lwp_thread->td_sp -= sizeof(void *); *(void **)lp2->lwp_thread->td_sp = (void *)cpu_heavy_restore; /* * pcb2->pcb_ldt: duplicated below, if necessary. * pcb2->pcb_savefpu: cloned above. * pcb2->pcb_flags: cloned above (always 0 here?). * pcb2->pcb_onfault: cloned above (always NULL here?). */ /* * XXX don't copy the i/o pages. this should probably be fixed. */ pcb2->pcb_ext = NULL; /* Copy the LDT, if necessary. */ if (pcb2->pcb_ldt != NULL) { if (flags & RFMEM) { atomic_add_int(&pcb2->pcb_ldt->ldt_refcnt, 1); } else { pcb2->pcb_ldt = user_ldt_alloc(pcb2, pcb2->pcb_ldt->ldt_len); } } bcopy(&lp1->lwp_thread->td_tls, &lp2->lwp_thread->td_tls, sizeof(lp2->lwp_thread->td_tls)); /* * Now, cpu_switch() can schedule the new lwp. * pcb_rsp is loaded pointing to the cpu_switch() stack frame * containing the return address when exiting cpu_switch. * This will normally be to fork_trampoline(), which will have * %rbx loaded with the new lwp's pointer. fork_trampoline() * will set up a stack to call fork_return(lp, frame); to complete * the return to user-mode. */ } /* * Prepare new lwp to return to the address specified in params. */ int cpu_prepare_lwp(struct lwp *lp, struct lwp_params *params) { struct trapframe *regs = lp->lwp_md.md_regs; void *bad_return = NULL; int error; regs->tf_rip = (long)params->lwp_func; regs->tf_rsp = (long)params->lwp_stack; /* Set up argument for function call */ regs->tf_rdi = (long)params->lwp_arg; /* JG Can this be in userspace addresses? */ /* * Set up fake return address. As the lwp function may never return, * we simply copy out a NULL pointer and force the lwp to receive * a SIGSEGV if it returns anyways. */ regs->tf_rsp -= sizeof(void *); error = copyout(&bad_return, (void *)regs->tf_rsp, sizeof(bad_return)); if (error) return (error); cpu_set_fork_handler(lp, (void (*)(void *, struct trapframe *))generic_lwp_return, lp); return (0); } /* * Intercept the return address from a freshly forked process that has NOT * been scheduled yet. * * This is needed to make kernel threads stay in kernel mode. */ void cpu_set_fork_handler(struct lwp *lp, void (*func)(void *, struct trapframe *), void *arg) { /* * Note that the trap frame follows the args, so the function * is really called like this: func(arg, frame); */ lp->lwp_thread->td_pcb->pcb_rbx = (long)func; /* function */ lp->lwp_thread->td_pcb->pcb_r12 = (long)arg; /* first arg */ } void cpu_set_thread_handler(thread_t td, void (*rfunc)(void), void *func, void *arg) { td->td_pcb->pcb_rbx = (long)func; td->td_pcb->pcb_r12 = (long)arg; td->td_switch = cpu_lwkt_switch; td->td_sp -= sizeof(void *); *(void **)td->td_sp = rfunc; /* exit function on return */ td->td_sp -= sizeof(void *); *(void **)td->td_sp = cpu_kthread_restore; } void cpu_lwp_exit(void) { struct thread *td = curthread; struct pcb *pcb; pcb = td->td_pcb; /* Some x86 functionality was dropped */ KKASSERT(pcb->pcb_ext == NULL); /* * disable all hardware breakpoints */ if (pcb->pcb_flags & PCB_DBREGS) { reset_dbregs(); pcb->pcb_flags &= ~PCB_DBREGS; } td->td_gd->gd_cnt.v_swtch++; crit_enter_quick(td); if (td->td_flags & TDF_TSLEEPQ) tsleep_remove(td); lwkt_deschedule_self(td); lwkt_remove_tdallq(td); cpu_thread_exit(); } /* * Terminate the current thread. The caller must have already acquired * the thread's rwlock and placed it on a reap list or otherwise notified * a reaper of its existance. We set a special assembly switch function which * releases td_rwlock after it has cleaned up the MMU state and switched * out the stack. * * Must be caller from a critical section and with the thread descheduled. */ void cpu_thread_exit(void) { npxexit(); curthread->td_switch = cpu_exit_switch; curthread->td_flags |= TDF_EXITING; lwkt_switch(); panic("cpu_thread_exit: lwkt_switch() unexpectedly returned"); } /* * Used by /dev/kmem to determine if we can safely read or write * the requested KVA range. Some portions of kernel memory are * not governed by our virtual page table. */ extern int64_t _end; extern void _start(void); int kvm_access_check(vm_offset_t saddr, vm_offset_t eaddr, int prot) { vm_offset_t addr; if (saddr >= trunc_page((vm_offset_t)&_start) && eaddr <= round_page((vm_offset_t)&_end)) { return 0; } if (saddr < KvaStart) return EFAULT; if (eaddr >= KvaEnd) return EFAULT; for (addr = saddr; addr < eaddr; addr += PAGE_SIZE) { if (pmap_kextract(addr) == 0) return EFAULT; } if (!kernacc((caddr_t)saddr, eaddr - saddr, prot)) return EFAULT; return 0; }
