/* $NetBSD: vm_machdep.c,v 1.119 2025/02/28 20:11:21 hans Exp $ */ /* * Copyright (c) 1994 Ludd, University of Lule}, Sweden. * All rights reserved. * * 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. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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. */ #include __KERNEL_RCSID(0, "$NetBSD: vm_machdep.c,v 1.119 2025/02/28 20:11:21 hans Exp $"); #include "opt_execfmt.h" #include "opt_compat_ultrix.h" #include "opt_multiprocessor.h" #include "opt_cputype.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Finish a fork operation, with process p2 nearly set up. * Copy and update the pcb and trap frame, making the child ready to run. * * Rig the child's kernel stack so that it will start out in * cpu_lwp_bootstrap() and call child_return() with p2 as an * argument. This causes the newly-created child process to go * directly to user level with an apparent return value of 0 from * fork(), while the parent process returns normally. * * p1 is the process being forked; if p1 == &proc0, we are creating * a kernel thread, and the return path and argument are specified with * `func' and `arg'. * * If an alternate user-level stack is requested (with non-zero values * in both the stack and stacksize args), set up the user stack pointer * accordingly. * * cpu_lwp_fork() copies parent process trapframe and creates a fake CALLS * frame on top of it, so that it can safely call child_return(). * We also take away mapping for the fourth page after pcb, so that * we get something like a "red zone" for the kernel stack. */ void cpu_lwp_bootstrap(void); void cpu_lwp_fork(struct lwp *l1, struct lwp *l2, void *stack, size_t stacksize, void (*func)(void *), void *arg) { struct callsframe *cf; extern int sret; /* Return address in trap routine */ struct pcb * const pcb2 = lwp_getpcb(l2); #ifdef DIAGNOSTIC /* * if p1 != curlwp && p1 == &proc0, we're creating a kernel thread. */ if (l1 != curlwp && l1 != &lwp0) panic("cpu_lwp_fork: curlwp"); #endif /* * Clear new pcb */ memset(pcb2, 0, sizeof(*pcb2)); /* * Copy the trap frame. */ const vaddr_t uv = uvm_lwp_getuarea(l2); struct trapframe * const tf = (struct trapframe *)(uv + USPACE) - 1; l2->l_md.md_utf = tf; *tf = *l1->l_md.md_utf; /* * Activate address space for the new process. The PTEs have * already been allocated by way of pmap_create(). * This writes the page table registers to the PCB. */ pcb2->pcb_pm = NULL; pmap_activate(l2); /* Mark guard page invalid in kernel stack */ kvtopte((uintptr_t)uv + REDZONEADDR)->pg_v = 0; /* * Set up the calls frame above (below) the trapframe and populate * it with something good. This is so that we can simulate that we * called cpu_lwp_bootstrap with a CALLS insn and it can return to * sret. */ cf = (struct callsframe *)tf - 1; cf->ca_cond = 0; cf->ca_maskpsw = 0x20000000; /* CALLS stack frame, no registers */ cf->ca_ap = 0; cf->ca_fp = 0; cf->ca_pc = (uintptr_t)&sret; /* return PC; userspace trampoline */ cf->ca_argno = 1; cf->ca_arg1 = 0; /* unused */ /* * Set up internal defs in PCB. This matches the "fake" CALLS frame * that were constructed earlier. */ pcb2->pcb_onfault = NULL; pcb2->AP = (uintptr_t)&cf->ca_argno; pcb2->KSP = (uintptr_t)cf; pcb2->FP = (uintptr_t)cf; pcb2->PC = (uintptr_t)cpu_lwp_bootstrap + 2; pcb2->PSL = PSL_HIGHIPL; pcb2->ESP = (uintptr_t)&pcb2->pcb_onfault; pcb2->SSP = (uintptr_t)l2; /* pcb->R[0] (oldlwp) set by Swtchto */ pcb2->R[1] = (uintptr_t)l2; pcb2->R[2] = (uintptr_t)func; pcb2->R[3] = (uintptr_t)arg; pcb2->pcb_paddr = kvtophys(pcb2); /* * If specified, give the child a different stack. */ if (stack != NULL) tf->tf_sp = (uintptr_t)stack + stacksize; /* * Set the last return information after fork(). * This is only interesting if the child will return to userspace, * but doesn't hurt otherwise. */ tf->tf_r0 = l1->l_proc->p_pid; /* parent pid. (shouldn't be needed) */ tf->tf_r1 = 1; tf->tf_psl = PSL_U|PSL_PREVU; } vaddr_t cpu_lwp_pc(struct lwp *l) { return l->l_md.md_utf->tf_pc; } void cpu_lwp_free(struct lwp *l, int proc) { (void)l; (void)proc; } void cpu_lwp_free2(struct lwp *l) { (void)l; } #ifdef EXEC_AOUT int cpu_exec_aout_makecmds(struct lwp *l, struct exec_package *epp) { return ENOEXEC; } #endif int sys_sysarch(struct lwp *l, const struct sys_sysarch_args *uap, register_t *retval) { return (ENOSYS); } /* * Map in a bunch of pages read/writable for the kernel. */ void ioaccess(vaddr_t vaddr, paddr_t paddr, size_t npgs) { uint32_t *pte = (uint32_t *)kvtopte(vaddr); int i; for (i = 0; i < npgs; i++) pte[i] = PG_V | PG_KW | (PG_PFNUM(paddr) + i); } /* * Opposite to the above: just forget their mapping. */ void iounaccess(vaddr_t vaddr, size_t npgs) { uint32_t *pte = (uint32_t *)kvtopte(vaddr); int i; for (i = 0; i < npgs; i++) pte[i] = 0; mtpr(0, PR_TBIA); } /* * Map a user I/O request into kernel virtual address space. * Note: the pages are already locked by uvm_vslock(), so we * do not need to pass an access_type to pmap_enter(). */ int vmapbuf(struct buf *bp, vsize_t len) { #if VAX46 || VAX48 || VAX49 || VAX53 || VAXANY vaddr_t faddr, taddr, off; paddr_t pa; struct proc *p; if (vax_boardtype != VAX_BTYP_46 && vax_boardtype != VAX_BTYP_48 && vax_boardtype != VAX_BTYP_49 && vax_boardtype != VAX_BTYP_53) return 0; if ((bp->b_flags & B_PHYS) == 0) panic("vmapbuf"); p = bp->b_proc; bp->b_saveaddr = bp->b_data; faddr = trunc_page((vaddr_t)bp->b_saveaddr); off = (vaddr_t)bp->b_data - faddr; len = round_page(off + len); taddr = uvm_km_alloc(phys_map, len, 0, UVM_KMF_VAONLY | UVM_KMF_WAITVA); bp->b_data = (void *)(taddr + off); len = atop(len); while (len--) { if (pmap_extract(vm_map_pmap(&p->p_vmspace->vm_map), faddr, &pa) == false) panic("vmapbuf: null page frame"); pmap_enter(vm_map_pmap(phys_map), taddr, trunc_page(pa), VM_PROT_READ|VM_PROT_WRITE, PMAP_WIRED); faddr += PAGE_SIZE; taddr += PAGE_SIZE; } pmap_update(vm_map_pmap(phys_map)); #endif return 0; } /* * Unmap a previously-mapped user I/O request. */ void vunmapbuf(struct buf *bp, vsize_t len) { #if VAX46 || VAX48 || VAX49 || VAX53 || VAXANY vaddr_t addr, off; if (vax_boardtype != VAX_BTYP_46 && vax_boardtype != VAX_BTYP_48 && vax_boardtype != VAX_BTYP_49 && vax_boardtype != VAX_BTYP_53) return; if ((bp->b_flags & B_PHYS) == 0) panic("vunmapbuf"); addr = trunc_page((vaddr_t)bp->b_data); off = (vaddr_t)bp->b_data - addr; len = round_page(off + len); pmap_remove(vm_map_pmap(phys_map), addr, addr + len); pmap_update(vm_map_pmap(phys_map)); uvm_km_free(phys_map, addr, len, UVM_KMF_VAONLY); bp->b_data = bp->b_saveaddr; bp->b_saveaddr = NULL; #endif }