trap.c revision 295041 
1/*-
2 * Copyright (c) 2015 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: head/sys/riscv/riscv/trap.c 295041 2016-01-29 15:12:31Z br $");
37
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/kernel.h>
41#include <sys/lock.h>
42#include <sys/mutex.h>
43#include <sys/pioctl.h>
44#include <sys/bus.h>
45#include <sys/proc.h>
46#include <sys/ptrace.h>
47#include <sys/syscall.h>
48#include <sys/sysent.h>
49
50#include <vm/vm.h>
51#include <vm/pmap.h>
52#include <vm/vm_kern.h>
53#include <vm/vm_map.h>
54#include <vm/vm_param.h>
55#include <vm/vm_extern.h>
56
57#include <machine/frame.h>
58#include <machine/pcb.h>
59#include <machine/pcpu.h>
60#include <machine/vmparam.h>
61
62#include <machine/resource.h>
63#include <machine/intr.h>
64
65extern register_t fsu_intr_fault;
66
67/* Called from exception.S */
68void do_trap_supervisor(struct trapframe *);
69void do_trap_user(struct trapframe *);
70
71static __inline void
72call_trapsignal(struct thread *td, int sig, int code, void *addr)
73{
74	ksiginfo_t ksi;
75
76	ksiginfo_init_trap(&ksi);
77	ksi.ksi_signo = sig;
78	ksi.ksi_code = code;
79	ksi.ksi_addr = addr;
80	trapsignal(td, &ksi);
81}
82
83int
84cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa)
85{
86	struct proc *p;
87	register_t *ap;
88	int nap;
89
90	nap = 8;
91	p = td->td_proc;
92	ap = &td->td_frame->tf_a[0];
93
94	sa->code = td->td_frame->tf_t[0];
95
96	if (sa->code == SYS_syscall || sa->code == SYS___syscall) {
97		sa->code = *ap++;
98		nap--;
99	}
100
101	if (p->p_sysent->sv_mask)
102		sa->code &= p->p_sysent->sv_mask;
103	if (sa->code >= p->p_sysent->sv_size)
104		sa->callp = &p->p_sysent->sv_table[0];
105	else
106		sa->callp = &p->p_sysent->sv_table[sa->code];
107
108	sa->narg = sa->callp->sy_narg;
109	memcpy(sa->args, ap, nap * sizeof(register_t));
110	if (sa->narg > nap)
111		panic("TODO: Could we have more then 8 args?");
112
113	td->td_retval[0] = 0;
114	td->td_retval[1] = 0;
115
116	return (0);
117}
118
119#include "../../kern/subr_syscall.c"
120
121static void
122dump_regs(struct trapframe *frame)
123{
124	int n;
125	int i;
126
127	n = (sizeof(frame->tf_t) / sizeof(frame->tf_t[0]));
128	for (i = 0; i < n; i++)
129		printf("t[%d] == 0x%016lx\n", i, frame->tf_t[i]);
130
131	n = (sizeof(frame->tf_s) / sizeof(frame->tf_s[0]));
132	for (i = 0; i < n; i++)
133		printf("s[%d] == 0x%016lx\n", i, frame->tf_s[i]);
134
135	n = (sizeof(frame->tf_a) / sizeof(frame->tf_a[0]));
136	for (i = 0; i < n; i++)
137		printf("a[%d] == 0x%016lx\n", i, frame->tf_a[i]);
138
139	printf("sepc == 0x%016lx\n", frame->tf_sepc);
140	printf("sstatus == 0x%016lx\n", frame->tf_sstatus);
141}
142
143static void
144svc_handler(struct trapframe *frame)
145{
146	struct syscall_args sa;
147	struct thread *td;
148	int error;
149
150	td = curthread;
151	td->td_frame = frame;
152
153	error = syscallenter(td, &sa);
154	syscallret(td, error, &sa);
155}
156
157static void
158data_abort(struct trapframe *frame, int lower)
159{
160	struct vm_map *map;
161	uint64_t sbadaddr;
162	struct thread *td;
163	struct pcb *pcb;
164	vm_prot_t ftype;
165	vm_offset_t va;
166	struct proc *p;
167	int ucode;
168	int error;
169	int sig;
170
171	td = curthread;
172	pcb = td->td_pcb;
173
174	/*
175	 * Special case for fuswintr and suswintr. These can't sleep so
176	 * handle them early on in the trap handler.
177	 */
178	if (__predict_false(pcb->pcb_onfault == (vm_offset_t)&fsu_intr_fault)) {
179		frame->tf_sepc = pcb->pcb_onfault;
180		return;
181	}
182
183	sbadaddr = frame->tf_sbadaddr;
184
185	p = td->td_proc;
186
187	if (lower)
188		map = &td->td_proc->p_vmspace->vm_map;
189	else {
190		/* The top bit tells us which range to use */
191		if ((sbadaddr >> 63) == 1)
192			map = kernel_map;
193		else
194			map = &td->td_proc->p_vmspace->vm_map;
195	}
196
197	va = trunc_page(sbadaddr);
198
199	if (frame->tf_scause == EXCP_STORE_ACCESS_FAULT) {
200		ftype = (VM_PROT_READ | VM_PROT_WRITE);
201	} else {
202		ftype = (VM_PROT_READ);
203	}
204
205	if (map != kernel_map) {
206		/*
207		 * Keep swapout from messing with us during this
208		 *	critical time.
209		 */
210		PROC_LOCK(p);
211		++p->p_lock;
212		PROC_UNLOCK(p);
213
214		/* Fault in the user page: */
215		error = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
216
217		PROC_LOCK(p);
218		--p->p_lock;
219		PROC_UNLOCK(p);
220	} else {
221		/*
222		 * Don't have to worry about process locking or stacks in the
223		 * kernel.
224		 */
225		error = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
226	}
227
228	if (error != KERN_SUCCESS) {
229		if (lower) {
230			sig = SIGSEGV;
231			if (error == KERN_PROTECTION_FAILURE)
232				ucode = SEGV_ACCERR;
233			else
234				ucode = SEGV_MAPERR;
235			call_trapsignal(td, sig, ucode, (void *)sbadaddr);
236		} else {
237			if (td->td_intr_nesting_level == 0 &&
238			    pcb->pcb_onfault != 0) {
239				frame->tf_a[0] = error;
240				frame->tf_sepc = pcb->pcb_onfault;
241				return;
242			}
243			dump_regs(frame);
244			panic("vm_fault failed: %lx, va 0x%016lx",
245				frame->tf_sepc, sbadaddr);
246		}
247	}
248
249	if (lower)
250		userret(td, frame);
251}
252
253void
254do_trap_supervisor(struct trapframe *frame)
255{
256	uint64_t exception;
257
258	exception = (frame->tf_scause & EXCP_MASK);
259	if (frame->tf_scause & EXCP_INTR) {
260		/* Interrupt */
261		riscv_cpu_intr(frame);
262		return;
263	}
264
265	CTR3(KTR_TRAP, "do_trap_supervisor: curthread: %p, sepc: %lx, frame: %p",
266	    curthread, frame->tf_sepc, frame);
267
268	switch(exception) {
269	case EXCP_LOAD_ACCESS_FAULT:
270	case EXCP_STORE_ACCESS_FAULT:
271	case EXCP_INSTR_ACCESS_FAULT:
272		data_abort(frame, 0);
273		break;
274	default:
275		dump_regs(frame);
276		panic("Unknown kernel exception %x badaddr %lx\n",
277			exception, frame->tf_sbadaddr);
278	}
279}
280
281void
282do_trap_user(struct trapframe *frame)
283{
284	uint64_t exception;
285
286	exception = (frame->tf_scause & EXCP_MASK);
287	if (frame->tf_scause & EXCP_INTR) {
288		/* Interrupt */
289		riscv_cpu_intr(frame);
290		return;
291	}
292
293	CTR3(KTR_TRAP, "do_trap_user: curthread: %p, sepc: %lx, frame: %p",
294	    curthread, frame->tf_sepc, frame);
295
296	switch(exception) {
297	case EXCP_LOAD_ACCESS_FAULT:
298	case EXCP_STORE_ACCESS_FAULT:
299	case EXCP_INSTR_ACCESS_FAULT:
300		data_abort(frame, 1);
301		break;
302	case EXCP_UMODE_ENV_CALL:
303		frame->tf_sepc += 4;	/* Next instruction */
304		svc_handler(frame);
305		break;
306	default:
307		dump_regs(frame);
308		panic("Unknown userland exception %x badaddr %lx\n",
309			exception, frame->tf_sbadaddr);
310	}
311}
312