1 /*- 2 * Copyright (c) 2015-2018 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 #if __riscv_xlen == 64 59 #define TP_OFFSET 16 /* sizeof(struct tcb) */ 60 #endif 61 62 /* 63 * Finish a fork operation, with process p2 nearly set up. 64 * Copy and update the pcb, set up the stack so that the child 65 * ready to run and return to user mode. 66 */ 67 void 68 cpu_fork(struct thread *td1, struct proc *p2, struct thread *td2, int flags) 69 { 70 struct pcb *pcb2; 71 struct trapframe *tf; 72 register_t val; 73 74 if ((flags & RFPROC) == 0) 75 return; 76 77 if (td1 == curthread) { 78 /* 79 * Save the tp. These normally happen in cpu_switch, 80 * but if userland changes this then forks this may 81 * not have happened. 82 */ 83 __asm __volatile("mv %0, tp" : "=&r"(val)); 84 td1->td_pcb->pcb_tp = val; 85 86 /* RISCVTODO: save the FPU state here */ 87 } 88 89 pcb2 = (struct pcb *)(td2->td_kstack + 90 td2->td_kstack_pages * PAGE_SIZE) - 1; 91 92 td2->td_pcb = pcb2; 93 bcopy(td1->td_pcb, pcb2, sizeof(*pcb2)); 94 95 tf = (struct trapframe *)STACKALIGN((struct trapframe *)pcb2 - 1); 96 bcopy(td1->td_frame, tf, sizeof(*tf)); 97 98 /* Clear syscall error flag */ 99 tf->tf_t[0] = 0; 100 101 /* Arguments for child */ 102 tf->tf_a[0] = 0; 103 tf->tf_a[1] = 0; 104 tf->tf_sstatus |= (SSTATUS_SPIE); /* Enable interrupts. */ 105 tf->tf_sstatus &= ~(SSTATUS_SPP); /* User mode. */ 106 107 td2->td_frame = tf; 108 109 /* Set the return value registers for fork() */ 110 td2->td_pcb->pcb_s[0] = (uintptr_t)fork_return; 111 td2->td_pcb->pcb_s[1] = (uintptr_t)td2; 112 td2->td_pcb->pcb_ra = (uintptr_t)fork_trampoline; 113 td2->td_pcb->pcb_sp = (uintptr_t)td2->td_frame; 114 115 /* Setup to release spin count in fork_exit(). */ 116 td2->td_md.md_spinlock_count = 1; 117 td2->td_md.md_saved_sstatus_ie = (SSTATUS_SIE); 118 } 119 120 void 121 cpu_reset(void) 122 { 123 124 sbi_shutdown(); 125 126 while(1); 127 } 128 129 void 130 cpu_thread_swapin(struct thread *td) 131 { 132 } 133 134 void 135 cpu_thread_swapout(struct thread *td) 136 { 137 } 138 139 void 140 cpu_set_syscall_retval(struct thread *td, int error) 141 { 142 struct trapframe *frame; 143 144 frame = td->td_frame; 145 146 switch (error) { 147 case 0: 148 frame->tf_a[0] = td->td_retval[0]; 149 frame->tf_a[1] = td->td_retval[1]; 150 frame->tf_t[0] = 0; /* syscall succeeded */ 151 break; 152 case ERESTART: 153 frame->tf_sepc -= 4; /* prev instruction */ 154 break; 155 case EJUSTRETURN: 156 break; 157 default: 158 frame->tf_a[0] = error; 159 frame->tf_t[0] = 1; /* syscall error */ 160 break; 161 } 162 } 163 164 /* 165 * Initialize machine state, mostly pcb and trap frame for a new 166 * thread, about to return to userspace. Put enough state in the new 167 * thread's PCB to get it to go back to the fork_return(), which 168 * finalizes the thread state and handles peculiarities of the first 169 * return to userspace for the new thread. 170 */ 171 void 172 cpu_copy_thread(struct thread *td, struct thread *td0) 173 { 174 175 bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe)); 176 bcopy(td0->td_pcb, td->td_pcb, sizeof(struct pcb)); 177 178 td->td_pcb->pcb_s[0] = (uintptr_t)fork_return; 179 td->td_pcb->pcb_s[1] = (uintptr_t)td; 180 td->td_pcb->pcb_ra = (uintptr_t)fork_trampoline; 181 td->td_pcb->pcb_sp = (uintptr_t)td->td_frame; 182 183 /* Setup to release spin count in fork_exit(). */ 184 td->td_md.md_spinlock_count = 1; 185 td->td_md.md_saved_sstatus_ie = (SSTATUS_SIE); 186 } 187 188 /* 189 * Set that machine state for performing an upcall that starts 190 * the entry function with the given argument. 191 */ 192 void 193 cpu_set_upcall(struct thread *td, void (*entry)(void *), void *arg, 194 stack_t *stack) 195 { 196 struct trapframe *tf; 197 198 tf = td->td_frame; 199 200 tf->tf_sp = STACKALIGN((uintptr_t)stack->ss_sp + stack->ss_size); 201 tf->tf_sepc = (register_t)entry; 202 tf->tf_a[0] = (register_t)arg; 203 } 204 205 int 206 cpu_set_user_tls(struct thread *td, void *tls_base) 207 { 208 struct pcb *pcb; 209 210 if ((uintptr_t)tls_base >= VM_MAXUSER_ADDRESS) 211 return (EINVAL); 212 213 pcb = td->td_pcb; 214 pcb->pcb_tp = (register_t)tls_base + TP_OFFSET; 215 if (td == curthread) 216 __asm __volatile("mv tp, %0" :: "r"(pcb->pcb_tp)); 217 218 return (0); 219 } 220 221 void 222 cpu_thread_exit(struct thread *td) 223 { 224 } 225 226 void 227 cpu_thread_alloc(struct thread *td) 228 { 229 230 td->td_pcb = (struct pcb *)(td->td_kstack + 231 td->td_kstack_pages * PAGE_SIZE) - 1; 232 td->td_frame = (struct trapframe *)STACKALIGN( 233 (caddr_t)td->td_pcb - 8 - sizeof(struct trapframe)); 234 } 235 236 void 237 cpu_thread_free(struct thread *td) 238 { 239 } 240 241 void 242 cpu_thread_clean(struct thread *td) 243 { 244 } 245 246 /* 247 * Intercept the return address from a freshly forked process that has NOT 248 * been scheduled yet. 249 * 250 * This is needed to make kernel threads stay in kernel mode. 251 */ 252 void 253 cpu_fork_kthread_handler(struct thread *td, void (*func)(void *), void *arg) 254 { 255 256 td->td_pcb->pcb_s[0] = (uintptr_t)func; 257 td->td_pcb->pcb_s[1] = (uintptr_t)arg; 258 td->td_pcb->pcb_ra = (uintptr_t)fork_trampoline; 259 td->td_pcb->pcb_sp = (uintptr_t)td->td_frame; 260 } 261 262 void 263 cpu_exit(struct thread *td) 264 { 265 } 266 267 void 268 swi_vm(void *v) 269 { 270 271 /* Nothing to do here - busdma bounce buffers are not implemented. */ 272 } 273