1 /* $NetBSD: vm_machdep.c,v 1.20 2023/10/06 11:53:27 skrll Exp $ */ 2 3 /* 4 * Copyright (c) 2006 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * 8 * Author: 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* Comments on functions from alpha/vm_machdep.c */ 33 34 #include <sys/cdefs.h> /* RCS ID & Copyright macro defns */ 35 36 #include <sys/param.h> 37 #include <sys/proc.h> 38 #include <sys/systm.h> 39 #include <sys/cpu.h> 40 #include <sys/atomic.h> 41 42 #include <machine/frame.h> 43 #include <machine/md_var.h> 44 #include <machine/pcb.h> 45 46 #include <uvm/uvm_extern.h> 47 48 void lwp_trampoline(void); 49 50 void 51 cpu_lwp_free(struct lwp *l, int proc) 52 { 53 54 /* XXX: Not yet. */ 55 (void)l; 56 (void)proc; 57 } 58 59 void 60 cpu_lwp_free2(struct lwp *l) 61 { 62 63 (void)l; 64 } 65 66 /* 67 * The cpu_switchto() function saves the context of the LWP which is 68 * currently running on the processor, and restores the context of the LWP 69 * specified by newlwp. man cpu_switchto(9) 70 */ 71 lwp_t * 72 cpu_switchto(lwp_t *oldlwp, lwp_t *newlwp, bool returning) 73 { 74 const struct lwp *l = curlwp; 75 struct pcb *oldpcb = oldlwp ? lwp_getpcb(oldlwp) : NULL; 76 struct pcb *newpcb = lwp_getpcb(newlwp); 77 struct cpu_info *ci = curcpu(); 78 register uint64_t reg9 __asm("r9"); 79 80 KASSERT(newlwp != NULL); 81 82 /* 83 * Issue barriers to coordinate mutex_exit on this CPU with 84 * mutex_vector_enter on another CPU. 85 * 86 * 1. Any prior mutex_exit by oldlwp must be visible to other 87 * CPUs before we set ci_curlwp := newlwp on this one, 88 * requiring a store-before-store barrier. 89 * 90 * 2. ci_curlwp := newlwp must be visible on all other CPUs 91 * before any subsequent mutex_exit by newlwp can even test 92 * whether there might be waiters, requiring a 93 * store-before-load barrier. 94 * 95 * See kern_mutex.c for details -- this is necessary for 96 * adaptive mutexes to detect whether the lwp is on the CPU in 97 * order to safely block without requiring atomic r/m/w in 98 * mutex_exit. 99 */ 100 membar_producer(); /* store-before-store */ 101 ci->ci_curlwp = newlwp; 102 membar_sync(); /* store-before-load */ 103 104 /* required for lwp_startup, copy oldlwp into r9, "mov r9=in0" */ 105 __asm __volatile("mov %0=%1" : "=r"(reg9) : "r"(oldlwp)); 106 107 /* XXX handle RAS eventually */ 108 109 if (oldlwp == NULL) { 110 restorectx(newpcb); 111 } else { 112 KASSERT(oldlwp == l); 113 swapctx(oldpcb, newpcb); 114 } 115 116 /* return oldlwp for the original thread that called cpu_switchto */ 117 return ((lwp_t *)reg9); 118 } 119 120 /* 121 * Finish a fork operation, with process p2 nearly set up. 122 * Copy and update the pcb and trap frame, making the child ready to run. 123 * 124 * Rig the child's kernel stack so that it will start out in 125 * lwp_trampoline() and call child_return() with p2 as an 126 * argument. This causes the newly-created child process to go 127 * directly to user level with an apparent return value of 0 from 128 * fork(), while the parent process returns normally. 129 * 130 * p1 is the process being forked; if p1 == &proc0, we are creating 131 * a kernel thread, and the return path and argument are specified with 132 * `func' and `arg'. 133 * 134 * If an alternate user-level stack is requested (with non-zero values 135 * in both the stack and stacksize args), set up the user stack pointer 136 * accordingly. 137 */ 138 void 139 cpu_lwp_fork(struct lwp *l1, struct lwp *l2, void *stack, size_t stacksize, 140 void (*func)(void *), void *arg) 141 { 142 vaddr_t ua1 = uvm_lwp_getuarea(l1); 143 vaddr_t ua2 = uvm_lwp_getuarea(l2); 144 struct pcb *pcb1 = lwp_getpcb(l1); 145 struct pcb *pcb2 = lwp_getpcb(l2); 146 147 struct trapframe *tf; 148 uint64_t ndirty; 149 150 /* 151 * Save the preserved registers and the high FP registers in the 152 * PCB if we're the parent (ie l1 == curlwp) so that we have 153 * a valid PCB. This also causes a RSE flush. We don't have to 154 * do that otherwise, because there wouldn't be anything important 155 * to save. 156 * 157 * Copy pcb from lwp l1 to l2. 158 */ 159 if (l1 == curlwp) { 160 /* Sync the PCB before we copy it. */ 161 if (savectx(pcb1) != 0) 162 panic("unexpected return from savectx()"); 163 /* ia64_highfp_save(td1); XXX */ 164 } else { 165 KASSERT(l1 == &lwp0); 166 } 167 168 /* 169 * create the child's kernel stack and backing store. We basically 170 * create an image of the parent's stack and backing store and 171 * adjust where necessary. 172 */ 173 *pcb2 = *pcb1; 174 175 l2->l_md.md_flags = l1->l_md.md_flags; 176 l2->l_md.md_tf = (struct trapframe *)(ua2 + UAREA_TF_OFFSET); 177 l2->l_md.user_stack = NULL; 178 l2->l_md.user_stack_size = 0; 179 KASSERT(l2->l_md.md_astpending == 0); 180 181 /* 182 * Copy the trapframe. 183 */ 184 tf = l2->l_md.md_tf; 185 *tf = *l1->l_md.md_tf; 186 187 /* XXX need something like this, but still not correct */ 188 ndirty = tf->tf_special.ndirty + (tf->tf_special.bspstore & 0x1ffUL); 189 memcpy((void *)(ua2 + UAREA_BSPSTORE_OFFSET), 190 (void *)(ua1 + UAREA_BSPSTORE_OFFSET), ndirty); 191 192 /* 193 * If specified, give the child a different stack. 194 */ 195 if (stack != NULL) { 196 l2->l_md.user_stack = stack; 197 l2->l_md.user_stack_size = stacksize; 198 tf->tf_special.sp = (unsigned long)stack + UAREA_SP_OFFSET; 199 tf->tf_special.bspstore = (unsigned long)stack + UAREA_BSPSTORE_OFFSET; 200 201 memcpy(stack, (void *)(ua1 + UAREA_BSPSTORE_OFFSET), ndirty); 202 } 203 204 /* Set-up the return values as expected by the fork() libc stub. */ 205 if (tf->tf_special.psr & IA64_PSR_IS) { 206 tf->tf_scratch.gr8 = 0; 207 tf->tf_scratch.gr10 = 1; 208 } else { 209 tf->tf_scratch.gr8 = 0; 210 tf->tf_scratch.gr9 = 1; 211 tf->tf_scratch.gr10 = 0; 212 } 213 214 pcb2->pcb_special.bspstore = ua2 + UAREA_BSPSTORE_OFFSET + ndirty; 215 pcb2->pcb_special.pfs = 0; 216 pcb2->pcb_special.sp = ua2 + UAREA_SP_OFFSET; 217 pcb2->pcb_special.rp = (unsigned long)FDESC_FUNC(lwp_trampoline); 218 tf->tf_scratch.gr2 = (unsigned long)FDESC_FUNC(func); 219 tf->tf_scratch.gr3 = (unsigned long)arg; 220 221 return; 222 } 223 224 /* 225 * Map a user I/O request into kernel virtual address space. 226 * Note: the pages are already locked by uvm_vslock(), so we 227 * do not need to pass an access_type to pmap_enter(). 228 */ 229 int 230 vmapbuf(struct buf *bp, vsize_t len) 231 { 232 panic("XXX %s implement", __func__); 233 return 0; 234 } 235 236 /* 237 * Unmap a previously-mapped user I/O request. 238 */ 239 void 240 vunmapbuf(struct buf *bp, vsize_t len) 241 { 242 panic("XXX %s implement", __func__); 243 return; 244 } 245
Indexes created Sun Oct 25 00:26:45 UTC 2026