2 * Copyright (c) 2015-2016 Ruslan Bukin <br@bsdpad.com>
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.
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).
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
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.
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
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/limits.h>
42 #include <sys/sf_buf.h>
43 #include <sys/signal.h>
44 #include <sys/unistd.h>
47 #include <vm/vm_page.h>
48 #include <vm/vm_map.h>
50 #include <vm/uma_int.h>
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>
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.
64 cpu_fork(struct thread *td1, struct proc *p2, struct thread *td2, int flags)
69 if ((flags & RFPROC) == 0)
72 pcb2 = (struct pcb *)(td2->td_kstack +
73 td2->td_kstack_pages * PAGE_SIZE) - 1;
76 bcopy(td1->td_pcb, pcb2, sizeof(*pcb2));
78 td2->td_pcb->pcb_l1addr =
79 vtophys(vmspace_pmap(td2->td_proc->p_vmspace)->pm_l1);
81 tf = (struct trapframe *)STACKALIGN((struct trapframe *)pcb2 - 1);
82 bcopy(td1->td_frame, tf, sizeof(*tf));
84 /* Clear syscall error flag */
87 /* Arguments for child */
90 tf->tf_sstatus |= (SSTATUS_SPIE); /* Enable interrupts. */
91 tf->tf_sstatus &= ~(SSTATUS_SPP); /* User mode. */
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;
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);
116 cpu_thread_swapin(struct thread *td)
121 cpu_thread_swapout(struct thread *td)
126 cpu_set_syscall_retval(struct thread *td, int error)
128 struct trapframe *frame;
130 frame = td->td_frame;
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 */
139 frame->tf_sepc -= 4; /* prev instruction */
144 frame->tf_a[0] = error;
145 frame->tf_t[0] = 1; /* syscall error */
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.
158 cpu_copy_thread(struct thread *td, struct thread *td0)
161 bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe));
162 bcopy(td0->td_pcb, td->td_pcb, sizeof(struct pcb));
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;
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);
175 * Set that machine state for performing an upcall that starts
176 * the entry function with the given argument.
179 cpu_set_upcall(struct thread *td, void (*entry)(void *), void *arg,
182 struct trapframe *tf = td->td_frame;
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;
190 cpu_set_user_tls(struct thread *td, void *tls_base)
194 if ((uintptr_t)tls_base >= VM_MAXUSER_ADDRESS)
198 pcb->pcb_tp = (register_t)tls_base;
204 cpu_thread_exit(struct thread *td)
209 cpu_thread_alloc(struct thread *td)
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));
219 cpu_thread_free(struct thread *td)
224 cpu_thread_clean(struct thread *td)
229 * Intercept the return address from a freshly forked process that has NOT
230 * been scheduled yet.
232 * This is needed to make kernel threads stay in kernel mode.
235 cpu_fork_kthread_handler(struct thread *td, void (*func)(void *), void *arg)
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;
245 cpu_exit(struct thread *td)
253 /* Nothing to do here - busdma bounce buffers are not implemented. */