/*- * Copyright (c) 1982, 1986 The Regents of the University of California. * Copyright (c) 1989, 1990 William Jolitz * Copyright (c) 1994 John Dyson * 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 $Hdr: vm_machdep.c 1.16.1.1 89/06/23$ * $FreeBSD$ */ /* * Copyright (c) 1994, 1995, 1996 Carnegie-Mellon University. * All rights reserved. * * Author: Chris G. Demetriou * * Permission to use, copy, modify and distribute this software and * its documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie the * rights to redistribute these changes. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * quick version of vm_fault */ void vm_fault_quick(v, prot) caddr_t v; int prot; { if (prot & VM_PROT_WRITE) subyte(v, fubyte(v)); else fubyte(v); } /* * Finish a fork operation, with process p2 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(p1, p2) register struct proc *p1, *p2; { struct user *up = p2->p_addr; p2->p_md.md_tf = p1->p_md.md_tf; p2->p_md.md_flags = p1->p_md.md_flags & MDP_FPUSED; /* * Cache the physical address of the pcb, so we can * swap to it easily. */ p2->p_md.md_pcbpaddr = (void*) vtophys((vm_offset_t) &up->u_pcb); /* * Copy floating point state from the FP chip to the PCB * if this process has state stored there. */ if (p1 == fpcurproc) { alpha_pal_wrfen(1); savefpstate(&fpcurproc->p_addr->u_pcb.pcb_fp); alpha_pal_wrfen(0); } /* * Copy pcb and stack from proc p1 to p2. * We do this as cheaply as possible, copying only the active * part of the stack. The stack and pcb need to agree; */ p2->p_addr->u_pcb = p1->p_addr->u_pcb; p2->p_addr->u_pcb.pcb_hw.apcb_usp = alpha_pal_rdusp(); /* * Set the floating point state. */ if ((p2->p_addr->u_pcb.pcb_fp_control & IEEE_INHERIT) == 0) { p2->p_addr->u_pcb.pcb_fp_control = 0; p2->p_addr->u_pcb.pcb_fp.fpr_cr = (FPCR_DYN_NORMAL | FPCR_INVD | FPCR_DZED | FPCR_OVFD | FPCR_INED | FPCR_UNFD); } /* * Arrange for a non-local goto when the new process * is started, to resume here, returning nonzero from setjmp. */ #ifdef DIAGNOSTIC if (p1 != curproc) panic("cpu_fork: curproc"); if ((up->u_pcb.pcb_hw.apcb_flags & ALPHA_PCB_FLAGS_FEN) != 0) printf("DANGER WILL ROBINSON: FEN SET IN cpu_fork!\n"); #endif /* * create the child's kernel stack, from scratch. */ { struct trapframe *p2tf; /* * Pick a stack pointer, leaving room for a trapframe; * copy trapframe from parent so return to user mode * will be to right address, with correct registers. */ p2tf = p2->p_md.md_tf = (struct trapframe *) ((char *)p2->p_addr + USPACE - sizeof(struct trapframe)); bcopy(p1->p_md.md_tf, p2->p_md.md_tf, sizeof(struct trapframe)); /* * Set up return-value registers as fork() libc stub expects. */ p2tf->tf_regs[FRAME_V0] = 0; /* child's pid (linux) */ p2tf->tf_regs[FRAME_A3] = 0; /* no error */ p2tf->tf_regs[FRAME_A4] = 1; /* is child (FreeBSD) */ /* * Arrange for continuation at child_return(), which * will return to exception_return(). Note that the child * process doesn't stay in the kernel for long! * * This is an inlined version of cpu_set_kpc. */ up->u_pcb.pcb_hw.apcb_ksp = (u_int64_t)p2tf; up->u_pcb.pcb_context[0] = (u_int64_t)child_return; /* s0: pc */ up->u_pcb.pcb_context[1] = (u_int64_t)exception_return; /* s1: ra */ up->u_pcb.pcb_context[2] = (u_long) p2; /* s2: a0 */ up->u_pcb.pcb_context[7] = (u_int64_t)switch_trampoline; /* ra: assembly magic */ } } /* * 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(p, func, arg) struct proc *p; void (*func) __P((void *)); void *arg; { /* * Note that the trap frame follows the args, so the function * is really called like this: func(arg, frame); */ p->p_addr->u_pcb.pcb_context[0] = (u_long) func; p->p_addr->u_pcb.pcb_context[2] = (u_long) arg; } /* * cpu_exit is called as the last action during exit. * We release the address space of the process, block interrupts, * and call switch_exit. switch_exit switches to proc0's PCB and stack, * then jumps into the middle of cpu_switch, as if it were switching * from proc0. */ void cpu_exit(p) register struct proc *p; { if (p == fpcurproc) fpcurproc = NULL; (void) splhigh(); cnt.v_swtch++; cpu_switch(p); panic("cpu_exit"); } void cpu_wait(p) struct proc *p; { /* drop per-process resources */ pmap_dispose_proc(p); /* and clean-out the vmspace */ vmspace_free(p->p_vmspace); } /* * Dump the machine specific header information at the start of a core dump. */ int cpu_coredump(p, vp, cred) struct proc *p; struct vnode *vp; struct ucred *cred; { return (vn_rdwr(UIO_WRITE, vp, (caddr_t) p->p_addr, ctob(UPAGES), (off_t)0, UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, cred, (int *)NULL, p)); } #ifdef notyet static void setredzone(pte, vaddr) u_short *pte; caddr_t vaddr; { /* eventually do this by setting up an expand-down stack segment for ss0: selector, allowing stack access down to top of u. this means though that protection violations need to be handled thru a double fault exception that must do an integral task switch to a known good context, within which a dump can be taken. a sensible scheme might be to save the initial context used by sched (that has physical memory mapped 1:1 at bottom) and take the dump while still in mapped mode */ } #endif /* * Map an IO request into kernel virtual address space. * * All requests are (re)mapped into kernel VA space. * Notice that we use b_bufsize for the size of the buffer * to be mapped. b_bcount might be modified by the driver. */ void vmapbuf(bp) register struct buf *bp; { register caddr_t addr, v, kva; vm_offset_t pa; if ((bp->b_flags & B_PHYS) == 0) panic("vmapbuf"); for (v = bp->b_saveaddr, addr = (caddr_t)trunc_page(bp->b_data); addr < bp->b_data + bp->b_bufsize; addr += PAGE_SIZE, v += PAGE_SIZE) { /* * Do the vm_fault if needed; do the copy-on-write thing * when reading stuff off device into memory. */ vm_fault_quick(addr, (bp->b_flags&B_READ)?(VM_PROT_READ|VM_PROT_WRITE):VM_PROT_READ); pa = trunc_page(pmap_kextract((vm_offset_t) addr)); if (pa == 0) panic("vmapbuf: page not present"); vm_page_hold(PHYS_TO_VM_PAGE(pa)); pmap_kenter((vm_offset_t) v, pa); } kva = bp->b_saveaddr; bp->b_saveaddr = bp->b_data; bp->b_data = kva + (((vm_offset_t) bp->b_data) & PAGE_MASK); } /* * Free the io map PTEs associated with this IO operation. * We also invalidate the TLB entries and restore the original b_addr. */ void vunmapbuf(bp) register struct buf *bp; { register caddr_t addr; vm_offset_t pa; if ((bp->b_flags & B_PHYS) == 0) panic("vunmapbuf"); for (addr = (caddr_t)trunc_page(bp->b_data); addr < bp->b_data + bp->b_bufsize; addr += PAGE_SIZE) { pa = trunc_page(pmap_kextract((vm_offset_t) addr)); pmap_kremove((vm_offset_t) addr); vm_page_unhold(PHYS_TO_VM_PAGE(pa)); } bp->b_data = bp->b_saveaddr; } /* * Force reset the processor by invalidating the entire address space! */ void cpu_reset() { prom_halt(0); } int grow_stack(p, sp) struct proc *p; size_t sp; { int rv; rv = vm_map_growstack (p, sp); if (rv != KERN_SUCCESS) return (0); return (1); } static int cnt_prezero; SYSCTL_INT(_machdep, OID_AUTO, cnt_prezero, CTLFLAG_RD, &cnt_prezero, 0, ""); /* * Implement the pre-zeroed page mechanism. * This routine is called from the idle loop. */ #define ZIDLE_LO(v) ((v) * 2 / 3) #define ZIDLE_HI(v) ((v) * 4 / 5) int vm_page_zero_idle() { static int free_rover; static int zero_state; vm_page_t m; int s; /* * Attempt to maintain approximately 1/2 of our free pages in a * PG_ZERO'd state. Add some hysteresis to (attempt to) avoid * generally zeroing a page when the system is near steady-state. * Otherwise we might get 'flutter' during disk I/O / IPC or * fast sleeps. We also do not want to be continuously zeroing * pages because doing so may flush our L1 and L2 caches too much. */ if (zero_state && vm_page_zero_count >= ZIDLE_LO(cnt.v_free_count)) return(0); if (vm_page_zero_count >= ZIDLE_HI(cnt.v_free_count)) return(0); #ifdef SMP if (try_mplock()) { #endif s = splvm(); m = vm_page_list_find(PQ_FREE, free_rover, FALSE); zero_state = 0; if (m != NULL && (m->flags & PG_ZERO) == 0) { vm_page_queues[m->queue].lcnt--; TAILQ_REMOVE(vm_page_queues[m->queue].pl, m, pageq); m->queue = PQ_NONE; splx(s); #if 0 rel_mplock(); #endif pmap_zero_page(VM_PAGE_TO_PHYS(m)); #if 0 get_mplock(); #endif (void)splvm(); vm_page_flag_set(m, PG_ZERO); m->queue = PQ_FREE + m->pc; vm_page_queues[m->queue].lcnt++; TAILQ_INSERT_TAIL(vm_page_queues[m->queue].pl, m, pageq); ++vm_page_zero_count; ++cnt_prezero; if (vm_page_zero_count >= ZIDLE_HI(cnt.v_free_count)) zero_state = 1; } free_rover = (free_rover + PQ_PRIME2) & PQ_L2_MASK; splx(s); #ifdef SMP rel_mplock(); #endif return (1); #ifdef SMP } #endif return (0); } /* * Software interrupt handler for queued VM system processing. */ void swi_vm() { #if 0 if (busdma_swi_pending != 0) busdma_swi(); #endif } /* * Tell whether this address is in some physical memory region. * Currently used by the kernel coredump code in order to avoid * dumping the ``ISA memory hole'' which could cause indefinite hangs, * or other unpredictable behaviour. */ int is_physical_memory(addr) vm_offset_t addr; { /* * stuff other tests for known memory-mapped devices (PCI?) * here */ return 1; }