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/param.h> 36 #include <sys/systm.h> 37 #include <sys/limits.h> 38 #include <sys/proc.h> 39 #include <sys/sf_buf.h> 40 #include <sys/signal.h> 41 #include <sys/unistd.h> 42 43 #include <vm/vm.h> 44 #include <vm/vm_page.h> 45 #include <vm/vm_map.h> 46 #include <vm/uma.h> 47 #include <vm/uma_int.h> 48 49 #include <machine/riscvreg.h> 50 #include <machine/cpu.h> 51 #include <machine/cpufunc.h> 52 #include <machine/pcb.h> 53 #include <machine/frame.h> 54 #include <machine/sbi.h> 55 56 #if __riscv_xlen == 64 57 #define TP_OFFSET 16 /* sizeof(struct tcb) */ 58 #endif 59 60 /* 61 * Finish a fork operation, with process p2 nearly set up. 62 * Copy and update the pcb, set up the stack so that the child 63 * ready to run and return to user mode. 64 */ 65 void 66 cpu_fork(struct thread *td1, struct proc *p2, struct thread *td2, int flags) 67 { 68 struct pcb *pcb2; 69 struct trapframe *tf; 70 71 if ((flags & RFPROC) == 0) 72 return; 73 74 /* RISCVTODO: save the FPU state here */ 75 76 pcb2 = (struct pcb *)(td2->td_kstack + 77 td2->td_kstack_pages * PAGE_SIZE) - 1; 78 79 td2->td_pcb = pcb2; 80 bcopy(td1->td_pcb, pcb2, sizeof(*pcb2)); 81 82 tf = (struct trapframe *)STACKALIGN((struct trapframe *)pcb2 - 1); 83 bcopy(td1->td_frame, tf, sizeof(*tf)); 84 85 /* Clear syscall error flag */ 86 tf->tf_t[0] = 0; 87 88 /* Arguments for child */ 89 tf->tf_a[0] = 0; 90 tf->tf_a[1] = 0; 91 tf->tf_sstatus |= (SSTATUS_SPIE); /* Enable interrupts. */ 92 tf->tf_sstatus &= ~(SSTATUS_SPP); /* User mode. */ 93 94 td2->td_frame = tf; 95 96 /* Set the return value registers for fork() */ 97 td2->td_pcb->pcb_s[0] = (uintptr_t)fork_return; 98 td2->td_pcb->pcb_s[1] = (uintptr_t)td2; 99 td2->td_pcb->pcb_ra = (uintptr_t)fork_trampoline; 100 td2->td_pcb->pcb_sp = (uintptr_t)td2->td_frame; 101 102 /* Setup to release spin count in fork_exit(). */ 103 td2->td_md.md_spinlock_count = 1; 104 td2->td_md.md_saved_sstatus_ie = (SSTATUS_SIE); 105 } 106 107 void 108 cpu_reset(void) 109 { 110 111 sbi_system_reset(SBI_SRST_TYPE_COLD_REBOOT, SBI_SRST_REASON_NONE); 112 113 while(1); 114 } 115 116 void 117 cpu_set_syscall_retval(struct thread *td, int error) 118 { 119 struct trapframe *frame; 120 121 frame = td->td_frame; 122 123 if (__predict_true(error == 0)) { 124 frame->tf_a[0] = td->td_retval[0]; 125 frame->tf_a[1] = td->td_retval[1]; 126 frame->tf_t[0] = 0; /* syscall succeeded */ 127 return; 128 } 129 130 switch (error) { 131 case ERESTART: 132 frame->tf_sepc -= 4; /* prev instruction */ 133 break; 134 case EJUSTRETURN: 135 break; 136 default: 137 frame->tf_a[0] = error; 138 frame->tf_t[0] = 1; /* syscall error */ 139 break; 140 } 141 } 142 143 /* 144 * Initialize machine state, mostly pcb and trap frame for a new 145 * thread, about to return to userspace. Put enough state in the new 146 * thread's PCB to get it to go back to the fork_return(), which 147 * finalizes the thread state and handles peculiarities of the first 148 * return to userspace for the new thread. 149 */ 150 void 151 cpu_copy_thread(struct thread *td, struct thread *td0) 152 { 153 154 bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe)); 155 bcopy(td0->td_pcb, td->td_pcb, sizeof(struct pcb)); 156 157 td->td_pcb->pcb_s[0] = (uintptr_t)fork_return; 158 td->td_pcb->pcb_s[1] = (uintptr_t)td; 159 td->td_pcb->pcb_ra = (uintptr_t)fork_trampoline; 160 td->td_pcb->pcb_sp = (uintptr_t)td->td_frame; 161 162 /* Setup to release spin count in fork_exit(). */ 163 td->td_md.md_spinlock_count = 1; 164 td->td_md.md_saved_sstatus_ie = (SSTATUS_SIE); 165 } 166 167 /* 168 * Set that machine state for performing an upcall that starts 169 * the entry function with the given argument. 170 */ 171 int 172 cpu_set_upcall(struct thread *td, void (*entry)(void *), void *arg, 173 stack_t *stack) 174 { 175 struct trapframe *tf; 176 177 tf = td->td_frame; 178 179 tf->tf_sp = STACKALIGN((uintptr_t)stack->ss_sp + stack->ss_size); 180 tf->tf_sepc = (register_t)entry; 181 tf->tf_a[0] = (register_t)arg; 182 return (0); 183 } 184 185 int 186 cpu_set_user_tls(struct thread *td, void *tls_base) 187 { 188 189 if ((uintptr_t)tls_base >= VM_MAXUSER_ADDRESS) 190 return (EINVAL); 191 192 /* 193 * The user TLS is set by modifying the trapframe's tp value, which 194 * will be restored when returning to userspace. 195 */ 196 td->td_frame->tf_tp = (register_t)tls_base + TP_OFFSET; 197 198 return (0); 199 } 200 201 void 202 cpu_thread_exit(struct thread *td) 203 { 204 } 205 206 void 207 cpu_thread_alloc(struct thread *td) 208 { 209 210 td->td_pcb = (struct pcb *)(td->td_kstack + 211 td->td_kstack_pages * PAGE_SIZE) - 1; 212 td->td_frame = (struct trapframe *)STACKALIGN( 213 (caddr_t)td->td_pcb - 8 - sizeof(struct trapframe)); 214 } 215 216 void 217 cpu_thread_free(struct thread *td) 218 { 219 } 220 221 void 222 cpu_thread_clean(struct thread *td) 223 { 224 } 225 226 /* 227 * Intercept the return address from a freshly forked process that has NOT 228 * been scheduled yet. 229 * 230 * This is needed to make kernel threads stay in kernel mode. 231 */ 232 void 233 cpu_fork_kthread_handler(struct thread *td, void (*func)(void *), void *arg) 234 { 235 236 td->td_pcb->pcb_s[0] = (uintptr_t)func; 237 td->td_pcb->pcb_s[1] = (uintptr_t)arg; 238 td->td_pcb->pcb_ra = (uintptr_t)fork_trampoline; 239 td->td_pcb->pcb_sp = (uintptr_t)td->td_frame; 240 } 241 242 void 243 cpu_exit(struct thread *td) 244 { 245 } 246 247 bool 248 cpu_exec_vmspace_reuse(struct proc *p __unused, vm_map_t map __unused) 249 { 250 251 return (true); 252 } 253 254 int 255 cpu_procctl(struct thread *td __unused, int idtype __unused, id_t id __unused, 256 int com __unused, void *data __unused) 257 { 258 259 return (EINVAL); 260 } 261 262 void 263 cpu_sync_core(void) 264 { 265 fence_i(); 266 } 267