1/*-
2 * Copyright (c) 2014 Andrew Turner
3 * Copyright (c) 2015-2017 Ruslan Bukin <br@bsdpad.com>
4 * All rights reserved.
5 *
6 * Portions of this software were developed by SRI International and the
7 * University of Cambridge Computer Laboratory under DARPA/AFRL contract
8 * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme.
9 *
10 * Portions of this software were developed by the University of Cambridge
11 * Computer Laboratory as part of the CTSRD Project, with support from the
12 * UK Higher Education Innovation Fund (HEIF).
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 *    notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 *    notice, this list of conditions and the following disclaimer in the
21 *    documentation and/or other materials provided with the distribution.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include <sys/param.h>
37#include <sys/systm.h>
38#include <sys/exec.h>
39#include <sys/imgact.h>
40#include <sys/kdb.h>
41#include <sys/kernel.h>
42#include <sys/ktr.h>
43#include <sys/limits.h>
44#include <sys/lock.h>
45#include <sys/mutex.h>
46#include <sys/proc.h>
47#include <sys/ptrace.h>
48#include <sys/reg.h>
49#include <sys/rwlock.h>
50#include <sys/sched.h>
51#include <sys/signalvar.h>
52#include <sys/syscallsubr.h>
53#include <sys/sysent.h>
54#include <sys/sysproto.h>
55#include <sys/ucontext.h>
56
57#include <machine/cpu.h>
58#include <machine/fpe.h>
59#include <machine/kdb.h>
60#include <machine/pcb.h>
61#include <machine/pte.h>
62#include <machine/riscvreg.h>
63#include <machine/sbi.h>
64#include <machine/trap.h>
65
66#include <vm/vm.h>
67#include <vm/vm_param.h>
68#include <vm/pmap.h>
69#include <vm/vm_map.h>
70
71static void get_fpcontext(struct thread *td, mcontext_t *mcp);
72static void set_fpcontext(struct thread *td, mcontext_t *mcp);
73
74_Static_assert(sizeof(mcontext_t) == 864, "mcontext_t size incorrect");
75_Static_assert(sizeof(ucontext_t) == 936, "ucontext_t size incorrect");
76_Static_assert(sizeof(siginfo_t) == 80, "siginfo_t size incorrect");
77
78int
79fill_regs(struct thread *td, struct reg *regs)
80{
81	struct trapframe *frame;
82
83	frame = td->td_frame;
84	regs->sepc = frame->tf_sepc;
85	regs->sstatus = frame->tf_sstatus;
86	regs->ra = frame->tf_ra;
87	regs->sp = frame->tf_sp;
88	regs->gp = frame->tf_gp;
89	regs->tp = frame->tf_tp;
90
91	memcpy(regs->t, frame->tf_t, sizeof(regs->t));
92	memcpy(regs->s, frame->tf_s, sizeof(regs->s));
93	memcpy(regs->a, frame->tf_a, sizeof(regs->a));
94
95	return (0);
96}
97
98int
99set_regs(struct thread *td, struct reg *regs)
100{
101	struct trapframe *frame;
102
103	frame = td->td_frame;
104	frame->tf_sepc = regs->sepc;
105	frame->tf_ra = regs->ra;
106	frame->tf_sp = regs->sp;
107	frame->tf_gp = regs->gp;
108	frame->tf_tp = regs->tp;
109
110	memcpy(frame->tf_t, regs->t, sizeof(frame->tf_t));
111	memcpy(frame->tf_s, regs->s, sizeof(frame->tf_s));
112	memcpy(frame->tf_a, regs->a, sizeof(frame->tf_a));
113
114	return (0);
115}
116
117int
118fill_fpregs(struct thread *td, struct fpreg *regs)
119{
120	struct pcb *pcb;
121
122	pcb = td->td_pcb;
123
124	if ((pcb->pcb_fpflags & PCB_FP_STARTED) != 0) {
125		/*
126		 * If we have just been running FPE instructions we will
127		 * need to save the state to memcpy it below.
128		 */
129		if (td == curthread)
130			fpe_state_save(td);
131
132		memcpy(regs->fp_x, pcb->pcb_x, sizeof(regs->fp_x));
133		regs->fp_fcsr = pcb->pcb_fcsr;
134	} else
135		memset(regs, 0, sizeof(*regs));
136
137	return (0);
138}
139
140int
141set_fpregs(struct thread *td, struct fpreg *regs)
142{
143	struct trapframe *frame;
144	struct pcb *pcb;
145
146	frame = td->td_frame;
147	pcb = td->td_pcb;
148
149	memcpy(pcb->pcb_x, regs->fp_x, sizeof(regs->fp_x));
150	pcb->pcb_fcsr = regs->fp_fcsr;
151	pcb->pcb_fpflags |= PCB_FP_STARTED;
152	frame->tf_sstatus &= ~SSTATUS_FS_MASK;
153	frame->tf_sstatus |= SSTATUS_FS_CLEAN;
154
155	return (0);
156}
157
158int
159fill_dbregs(struct thread *td, struct dbreg *regs)
160{
161
162	panic("fill_dbregs");
163}
164
165int
166set_dbregs(struct thread *td, struct dbreg *regs)
167{
168
169	panic("set_dbregs");
170}
171
172void
173exec_setregs(struct thread *td, struct image_params *imgp, uintptr_t stack)
174{
175	struct trapframe *tf;
176	struct pcb *pcb;
177
178	tf = td->td_frame;
179	pcb = td->td_pcb;
180
181	memset(tf, 0, sizeof(struct trapframe));
182
183	tf->tf_a[0] = stack;
184	tf->tf_sp = STACKALIGN(stack);
185	tf->tf_ra = imgp->entry_addr;
186	tf->tf_sepc = imgp->entry_addr;
187
188	pcb->pcb_fpflags &= ~PCB_FP_STARTED;
189}
190
191/* Sanity check these are the same size, they will be memcpy'd to and from */
192CTASSERT(sizeof(((struct trapframe *)0)->tf_a) ==
193    sizeof((struct gpregs *)0)->gp_a);
194CTASSERT(sizeof(((struct trapframe *)0)->tf_s) ==
195    sizeof((struct gpregs *)0)->gp_s);
196CTASSERT(sizeof(((struct trapframe *)0)->tf_t) ==
197    sizeof((struct gpregs *)0)->gp_t);
198CTASSERT(sizeof(((struct trapframe *)0)->tf_a) ==
199    sizeof((struct reg *)0)->a);
200CTASSERT(sizeof(((struct trapframe *)0)->tf_s) ==
201    sizeof((struct reg *)0)->s);
202CTASSERT(sizeof(((struct trapframe *)0)->tf_t) ==
203    sizeof((struct reg *)0)->t);
204
205int
206get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
207{
208	struct trapframe *tf = td->td_frame;
209
210	memcpy(mcp->mc_gpregs.gp_t, tf->tf_t, sizeof(mcp->mc_gpregs.gp_t));
211	memcpy(mcp->mc_gpregs.gp_s, tf->tf_s, sizeof(mcp->mc_gpregs.gp_s));
212	memcpy(mcp->mc_gpregs.gp_a, tf->tf_a, sizeof(mcp->mc_gpregs.gp_a));
213
214	if (clear_ret & GET_MC_CLEAR_RET) {
215		mcp->mc_gpregs.gp_a[0] = 0;
216		mcp->mc_gpregs.gp_t[0] = 0; /* clear syscall error */
217	}
218
219	mcp->mc_gpregs.gp_ra = tf->tf_ra;
220	mcp->mc_gpregs.gp_sp = tf->tf_sp;
221	mcp->mc_gpregs.gp_gp = tf->tf_gp;
222	mcp->mc_gpregs.gp_tp = tf->tf_tp;
223	mcp->mc_gpregs.gp_sepc = tf->tf_sepc;
224	mcp->mc_gpregs.gp_sstatus = tf->tf_sstatus;
225	get_fpcontext(td, mcp);
226
227	return (0);
228}
229
230int
231set_mcontext(struct thread *td, mcontext_t *mcp)
232{
233	struct trapframe *tf;
234
235	tf = td->td_frame;
236
237	/*
238	 * Permit changes to the USTATUS bits of SSTATUS.
239	 *
240	 * Ignore writes to read-only bits (SD, XS).
241	 *
242	 * Ignore writes to the FS field as set_fpcontext() will set
243	 * it explicitly.
244	 */
245	if (((mcp->mc_gpregs.gp_sstatus ^ tf->tf_sstatus) &
246	    ~(SSTATUS_SD | SSTATUS_XS_MASK | SSTATUS_FS_MASK | SSTATUS_UPIE |
247	    SSTATUS_UIE)) != 0)
248		return (EINVAL);
249
250	memcpy(tf->tf_t, mcp->mc_gpregs.gp_t, sizeof(tf->tf_t));
251	memcpy(tf->tf_s, mcp->mc_gpregs.gp_s, sizeof(tf->tf_s));
252	memcpy(tf->tf_a, mcp->mc_gpregs.gp_a, sizeof(tf->tf_a));
253
254	tf->tf_ra = mcp->mc_gpregs.gp_ra;
255	tf->tf_sp = mcp->mc_gpregs.gp_sp;
256	tf->tf_gp = mcp->mc_gpregs.gp_gp;
257	tf->tf_sepc = mcp->mc_gpregs.gp_sepc;
258	tf->tf_sstatus = mcp->mc_gpregs.gp_sstatus;
259	set_fpcontext(td, mcp);
260
261	return (0);
262}
263
264static void
265get_fpcontext(struct thread *td, mcontext_t *mcp)
266{
267	struct pcb *curpcb;
268
269	critical_enter();
270
271	curpcb = curthread->td_pcb;
272
273	KASSERT(td->td_pcb == curpcb, ("Invalid fpe pcb"));
274
275	if ((curpcb->pcb_fpflags & PCB_FP_STARTED) != 0) {
276		/*
277		 * If we have just been running FPE instructions we will
278		 * need to save the state to memcpy it below.
279		 */
280		fpe_state_save(td);
281
282		KASSERT((curpcb->pcb_fpflags & ~PCB_FP_USERMASK) == 0,
283		    ("Non-userspace FPE flags set in get_fpcontext"));
284		memcpy(mcp->mc_fpregs.fp_x, curpcb->pcb_x,
285		    sizeof(mcp->mc_fpregs.fp_x));
286		mcp->mc_fpregs.fp_fcsr = curpcb->pcb_fcsr;
287		mcp->mc_fpregs.fp_flags = curpcb->pcb_fpflags;
288		mcp->mc_flags |= _MC_FP_VALID;
289	}
290
291	critical_exit();
292}
293
294static void
295set_fpcontext(struct thread *td, mcontext_t *mcp)
296{
297	struct pcb *curpcb;
298
299	td->td_frame->tf_sstatus &= ~SSTATUS_FS_MASK;
300	td->td_frame->tf_sstatus |= SSTATUS_FS_OFF;
301
302	critical_enter();
303
304	if ((mcp->mc_flags & _MC_FP_VALID) != 0) {
305		curpcb = curthread->td_pcb;
306		/* FPE usage is enabled, override registers. */
307		memcpy(curpcb->pcb_x, mcp->mc_fpregs.fp_x,
308		    sizeof(mcp->mc_fpregs.fp_x));
309		curpcb->pcb_fcsr = mcp->mc_fpregs.fp_fcsr;
310		curpcb->pcb_fpflags = mcp->mc_fpregs.fp_flags & PCB_FP_USERMASK;
311		td->td_frame->tf_sstatus |= SSTATUS_FS_CLEAN;
312	}
313
314	critical_exit();
315}
316
317int
318sys_sigreturn(struct thread *td, struct sigreturn_args *uap)
319{
320	ucontext_t uc;
321	int error;
322
323	if (copyin(uap->sigcntxp, &uc, sizeof(uc)))
324		return (EFAULT);
325
326	error = set_mcontext(td, &uc.uc_mcontext);
327	if (error != 0)
328		return (error);
329
330	/* Restore signal mask. */
331	kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask, NULL, 0);
332
333	return (EJUSTRETURN);
334}
335
336void
337sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
338{
339	struct sigframe *fp, frame;
340	struct sysentvec *sysent;
341	struct trapframe *tf;
342	struct sigacts *psp;
343	struct thread *td;
344	struct proc *p;
345	int onstack;
346	int sig;
347
348	td = curthread;
349	p = td->td_proc;
350	PROC_LOCK_ASSERT(p, MA_OWNED);
351
352	sig = ksi->ksi_signo;
353	psp = p->p_sigacts;
354	mtx_assert(&psp->ps_mtx, MA_OWNED);
355
356	tf = td->td_frame;
357	onstack = sigonstack(tf->tf_sp);
358
359	CTR4(KTR_SIG, "sendsig: td=%p (%s) catcher=%p sig=%d", td, p->p_comm,
360	    catcher, sig);
361
362	/* Allocate and validate space for the signal handler context. */
363	if ((td->td_pflags & TDP_ALTSTACK) != 0 && !onstack &&
364	    SIGISMEMBER(psp->ps_sigonstack, sig)) {
365		fp = (struct sigframe *)((uintptr_t)td->td_sigstk.ss_sp +
366		    td->td_sigstk.ss_size);
367	} else {
368		fp = (struct sigframe *)td->td_frame->tf_sp;
369	}
370
371	/* Make room, keeping the stack aligned */
372	fp--;
373	fp = (struct sigframe *)STACKALIGN(fp);
374
375	/* Fill in the frame to copy out */
376	bzero(&frame, sizeof(frame));
377	get_mcontext(td, &frame.sf_uc.uc_mcontext, 0);
378	frame.sf_si = ksi->ksi_info;
379	frame.sf_uc.uc_sigmask = *mask;
380	frame.sf_uc.uc_stack = td->td_sigstk;
381	frame.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK) != 0 ?
382	    (onstack ? SS_ONSTACK : 0) : SS_DISABLE;
383	mtx_unlock(&psp->ps_mtx);
384	PROC_UNLOCK(td->td_proc);
385
386	/* Copy the sigframe out to the user's stack. */
387	if (copyout(&frame, fp, sizeof(*fp)) != 0) {
388		/* Process has trashed its stack. Kill it. */
389		CTR2(KTR_SIG, "sendsig: sigexit td=%p fp=%p", td, fp);
390		PROC_LOCK(p);
391		sigexit(td, SIGILL);
392	}
393
394	tf->tf_a[0] = sig;
395	tf->tf_a[1] = (register_t)&fp->sf_si;
396	tf->tf_a[2] = (register_t)&fp->sf_uc;
397
398	tf->tf_sepc = (register_t)catcher;
399	tf->tf_sp = (register_t)fp;
400
401	sysent = p->p_sysent;
402	if (PROC_HAS_SHP(p))
403		tf->tf_ra = (register_t)PROC_SIGCODE(p);
404	else
405		tf->tf_ra = (register_t)(PROC_PS_STRINGS(p) -
406		    *(sysent->sv_szsigcode));
407
408	CTR3(KTR_SIG, "sendsig: return td=%p pc=%#x sp=%#x", td, tf->tf_sepc,
409	    tf->tf_sp);
410
411	PROC_LOCK(p);
412	mtx_lock(&psp->ps_mtx);
413}
414