2 * Copyright (c) 2015-2017 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>
58 #if __riscv_xlen == 64
59 #define TP_OFFSET 16 /* sizeof(struct tcb) */
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.
68 cpu_fork(struct thread *td1, struct proc *p2, struct thread *td2, int flags)
74 if ((flags & RFPROC) == 0)
77 if (td1 == curthread) {
79 * Save the tp. These normally happen in cpu_switch,
80 * but if userland changes this then forks this may
83 __asm __volatile("mv %0, tp" : "=&r"(val));
84 td1->td_pcb->pcb_tp = val;
86 /* RISCVTODO: save the FPU state here */
89 pcb2 = (struct pcb *)(td2->td_kstack +
90 td2->td_kstack_pages * PAGE_SIZE) - 1;
93 bcopy(td1->td_pcb, pcb2, sizeof(*pcb2));
95 td2->td_pcb->pcb_l1addr =
96 vtophys(vmspace_pmap(td2->td_proc->p_vmspace)->pm_l1);
98 tf = (struct trapframe *)STACKALIGN((struct trapframe *)pcb2 - 1);
99 bcopy(td1->td_frame, tf, sizeof(*tf));
101 /* Clear syscall error flag */
104 /* Arguments for child */
107 tf->tf_sstatus |= (SSTATUS_SPIE); /* Enable interrupts. */
108 tf->tf_sstatus |= (SSTATUS_SUM); /* Supervisor can access userspace. */
109 tf->tf_sstatus &= ~(SSTATUS_SPP); /* User mode. */
113 /* Set the return value registers for fork() */
114 td2->td_pcb->pcb_s[0] = (uintptr_t)fork_return;
115 td2->td_pcb->pcb_s[1] = (uintptr_t)td2;
116 td2->td_pcb->pcb_ra = (uintptr_t)fork_trampoline;
117 td2->td_pcb->pcb_sp = (uintptr_t)td2->td_frame;
119 /* Setup to release spin count in fork_exit(). */
120 td2->td_md.md_spinlock_count = 1;
121 td2->td_md.md_saved_sstatus_ie = (SSTATUS_SIE);
134 cpu_thread_swapin(struct thread *td)
139 cpu_thread_swapout(struct thread *td)
144 cpu_set_syscall_retval(struct thread *td, int error)
146 struct trapframe *frame;
148 frame = td->td_frame;
152 frame->tf_a[0] = td->td_retval[0];
153 frame->tf_a[1] = td->td_retval[1];
154 frame->tf_t[0] = 0; /* syscall succeeded */
157 frame->tf_sepc -= 4; /* prev instruction */
162 frame->tf_a[0] = error;
163 frame->tf_t[0] = 1; /* syscall error */
169 * Initialize machine state, mostly pcb and trap frame for a new
170 * thread, about to return to userspace. Put enough state in the new
171 * thread's PCB to get it to go back to the fork_return(), which
172 * finalizes the thread state and handles peculiarities of the first
173 * return to userspace for the new thread.
176 cpu_copy_thread(struct thread *td, struct thread *td0)
179 bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe));
180 bcopy(td0->td_pcb, td->td_pcb, sizeof(struct pcb));
182 td->td_pcb->pcb_s[0] = (uintptr_t)fork_return;
183 td->td_pcb->pcb_s[1] = (uintptr_t)td;
184 td->td_pcb->pcb_ra = (uintptr_t)fork_trampoline;
185 td->td_pcb->pcb_sp = (uintptr_t)td->td_frame;
187 /* Setup to release spin count in fork_exit(). */
188 td->td_md.md_spinlock_count = 1;
189 td->td_md.md_saved_sstatus_ie = (SSTATUS_SIE);
193 * Set that machine state for performing an upcall that starts
194 * the entry function with the given argument.
197 cpu_set_upcall(struct thread *td, void (*entry)(void *), void *arg,
200 struct trapframe *tf;
204 tf->tf_sp = STACKALIGN((uintptr_t)stack->ss_sp + stack->ss_size);
205 tf->tf_sepc = (register_t)entry;
206 tf->tf_a[0] = (register_t)arg;
210 cpu_set_user_tls(struct thread *td, void *tls_base)
214 if ((uintptr_t)tls_base >= VM_MAXUSER_ADDRESS)
218 pcb->pcb_tp = (register_t)tls_base + TP_OFFSET;
220 __asm __volatile("mv tp, %0" :: "r"(pcb->pcb_tp));
226 cpu_thread_exit(struct thread *td)
231 cpu_thread_alloc(struct thread *td)
234 td->td_pcb = (struct pcb *)(td->td_kstack +
235 td->td_kstack_pages * PAGE_SIZE) - 1;
236 td->td_frame = (struct trapframe *)STACKALIGN(
237 (caddr_t)td->td_pcb - 8 - sizeof(struct trapframe));
241 cpu_thread_free(struct thread *td)
246 cpu_thread_clean(struct thread *td)
251 * Intercept the return address from a freshly forked process that has NOT
252 * been scheduled yet.
254 * This is needed to make kernel threads stay in kernel mode.
257 cpu_fork_kthread_handler(struct thread *td, void (*func)(void *), void *arg)
260 td->td_pcb->pcb_s[0] = (uintptr_t)func;
261 td->td_pcb->pcb_s[1] = (uintptr_t)arg;
262 td->td_pcb->pcb_ra = (uintptr_t)fork_trampoline;
263 td->td_pcb->pcb_sp = (uintptr_t)td->td_frame;
267 cpu_exit(struct thread *td)
275 /* Nothing to do here - busdma bounce buffers are not implemented. */