1 /*- 2 * Copyright (c) 2015-2016 Ruslan Bukin <br@bsdpad.com> 3 * All rights reserved. 4 * 5 * Portions of this software were developed by SRI International and the 6 * University of Cambridge Computer Laboratory under DARPA/AFRL contract 7 * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme. 8 * 9 * Portions of this software were developed by the University of Cambridge 10 * Computer Laboratory as part of the CTSRD Project, with support from the 11 * UK Higher Education Innovation Fund (HEIF). 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/limits.h> 41 #include <sys/proc.h> 42 #include <sys/sf_buf.h> 43 #include <sys/signal.h> 44 #include <sys/unistd.h> 45 46 #include <vm/vm.h> 47 #include <vm/vm_page.h> 48 #include <vm/vm_map.h> 49 #include <vm/uma.h> 50 #include <vm/uma_int.h> 51 52 #include <machine/riscvreg.h> 53 #include <machine/cpu.h> 54 #include <machine/pcb.h> 55 #include <machine/frame.h> 56 #include <machine/sbi.h> 57 58 /* 59 * Finish a fork operation, with process p2 nearly set up. 60 * Copy and update the pcb, set up the stack so that the child 61 * ready to run and return to user mode. 62 */ 63 void 64 cpu_fork(struct thread *td1, struct proc *p2, struct thread *td2, int flags) 65 { 66 struct pcb *pcb2; 67 struct trapframe *tf; 68 69 if ((flags & RFPROC) == 0) 70 return; 71 72 pcb2 = (struct pcb *)(td2->td_kstack + 73 td2->td_kstack_pages * PAGE_SIZE) - 1; 74 75 td2->td_pcb = pcb2; 76 bcopy(td1->td_pcb, pcb2, sizeof(*pcb2)); 77 78 td2->td_pcb->pcb_l1addr = 79 vtophys(vmspace_pmap(td2->td_proc->p_vmspace)->pm_l1); 80 81 tf = (struct trapframe *)STACKALIGN((struct trapframe *)pcb2 - 1); 82 bcopy(td1->td_frame, tf, sizeof(*tf)); 83 84 /* Clear syscall error flag */ 85 tf->tf_t[0] = 0; 86 87 /* Arguments for child */ 88 tf->tf_a[0] = 0; 89 tf->tf_a[1] = 0; 90 tf->tf_sstatus |= (SSTATUS_SPIE); /* Enable interrupts. */ 91 tf->tf_sstatus &= ~(SSTATUS_SPP); /* User mode. */ 92 93 td2->td_frame = tf; 94 95 /* Set the return value registers for fork() */ 96 td2->td_pcb->pcb_s[0] = (uintptr_t)fork_return; 97 td2->td_pcb->pcb_s[1] = (uintptr_t)td2; 98 td2->td_pcb->pcb_ra = (uintptr_t)fork_trampoline; 99 td2->td_pcb->pcb_sp = (uintptr_t)td2->td_frame; 100 101 /* Setup to release spin count in fork_exit(). */ 102 td2->td_md.md_spinlock_count = 1; 103 td2->td_md.md_saved_sstatus_ie = (SSTATUS_SIE); 104 } 105 106 void 107 cpu_reset(void) 108 { 109 110 sbi_shutdown(); 111 112 while(1); 113 } 114 115 void 116 cpu_thread_swapin(struct thread *td) 117 { 118 } 119 120 void 121 cpu_thread_swapout(struct thread *td) 122 { 123 } 124 125 void 126 cpu_set_syscall_retval(struct thread *td, int error) 127 { 128 struct trapframe *frame; 129 130 frame = td->td_frame; 131 132 switch (error) { 133 case 0: 134 frame->tf_a[0] = td->td_retval[0]; 135 frame->tf_a[1] = td->td_retval[1]; 136 frame->tf_t[0] = 0; /* syscall succeeded */ 137 break; 138 case ERESTART: 139 frame->tf_sepc -= 4; /* prev instruction */ 140 break; 141 case EJUSTRETURN: 142 break; 143 default: 144 frame->tf_a[0] = error; 145 frame->tf_t[0] = 1; /* syscall error */ 146 break; 147 } 148 } 149 150 /* 151 * Initialize machine state, mostly pcb and trap frame for a new 152 * thread, about to return to userspace. Put enough state in the new 153 * thread's PCB to get it to go back to the fork_return(), which 154 * finalizes the thread state and handles peculiarities of the first 155 * return to userspace for the new thread. 156 */ 157 void 158 cpu_copy_thread(struct thread *td, struct thread *td0) 159 { 160 161 bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe)); 162 bcopy(td0->td_pcb, td->td_pcb, sizeof(struct pcb)); 163 164 td->td_pcb->pcb_s[0] = (uintptr_t)fork_return; 165 td->td_pcb->pcb_s[1] = (uintptr_t)td; 166 td->td_pcb->pcb_ra = (uintptr_t)fork_trampoline; 167 td->td_pcb->pcb_sp = (uintptr_t)td->td_frame; 168 169 /* Setup to release spin count in fork_exit(). */ 170 td->td_md.md_spinlock_count = 1; 171 td->td_md.md_saved_sstatus_ie = (SSTATUS_SIE); 172 } 173 174 /* 175 * Set that machine state for performing an upcall that starts 176 * the entry function with the given argument. 177 */ 178 void 179 cpu_set_upcall(struct thread *td, void (*entry)(void *), void *arg, 180 stack_t *stack) 181 { 182 struct trapframe *tf = td->td_frame; 183 184 tf->tf_sp = STACKALIGN((uintptr_t)stack->ss_sp + stack->ss_size); 185 tf->tf_sepc = (register_t)entry; 186 tf->tf_a[0] = (register_t)arg; 187 } 188 189 int 190 cpu_set_user_tls(struct thread *td, void *tls_base) 191 { 192 struct pcb *pcb; 193 194 if ((uintptr_t)tls_base >= VM_MAXUSER_ADDRESS) 195 return (EINVAL); 196 197 pcb = td->td_pcb; 198 pcb->pcb_tp = (register_t)tls_base; 199 200 return (0); 201 } 202 203 void 204 cpu_thread_exit(struct thread *td) 205 { 206 } 207 208 void 209 cpu_thread_alloc(struct thread *td) 210 { 211 212 td->td_pcb = (struct pcb *)(td->td_kstack + 213 td->td_kstack_pages * PAGE_SIZE) - 1; 214 td->td_frame = (struct trapframe *)STACKALIGN( 215 (caddr_t)td->td_pcb - 8 - sizeof(struct trapframe)); 216 } 217 218 void 219 cpu_thread_free(struct thread *td) 220 { 221 } 222 223 void 224 cpu_thread_clean(struct thread *td) 225 { 226 } 227 228 /* 229 * Intercept the return address from a freshly forked process that has NOT 230 * been scheduled yet. 231 * 232 * This is needed to make kernel threads stay in kernel mode. 233 */ 234 void 235 cpu_fork_kthread_handler(struct thread *td, void (*func)(void *), void *arg) 236 { 237 238 td->td_pcb->pcb_s[0] = (uintptr_t)func; 239 td->td_pcb->pcb_s[1] = (uintptr_t)arg; 240 td->td_pcb->pcb_ra = (uintptr_t)fork_trampoline; 241 td->td_pcb->pcb_sp = (uintptr_t)td->td_frame; 242 } 243 244 void 245 cpu_exit(struct thread *td) 246 { 247 } 248 249 void 250 swi_vm(void *v) 251 { 252 253 /* Nothing to do here - busdma bounce buffers are not implemented. */ 254 } 255