sig_machdep.c revision 1.55 
1/*	$NetBSD: sig_machdep.c,v 1.55 2023/12/20 15:29:06 thorpej Exp $	*/
2
3/*
4 * Copyright (C) 1995, 1996 Wolfgang Solfrank.
5 * Copyright (C) 1995, 1996 TooLs GmbH.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by TooLs GmbH.
19 * 4. The name of TooLs GmbH may not be used to endorse or promote products
20 *    derived from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
27 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
28 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
29 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
30 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
31 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34#include <sys/cdefs.h>
35__KERNEL_RCSID(0, "$NetBSD: sig_machdep.c,v 1.55 2023/12/20 15:29:06 thorpej Exp $");
36
37#ifdef _KERNEL_OPT
38#include "opt_altivec.h"
39#include "opt_ppcarch.h"
40#endif
41
42#include <sys/param.h>
43#include <sys/mount.h>
44#include <sys/proc.h>
45#include <sys/syscallargs.h>
46#include <sys/systm.h>
47#include <sys/ucontext.h>
48#include <sys/cpu.h>
49
50#include <uvm/uvm_extern.h>
51
52#include <powerpc/fpu.h>
53#include <powerpc/altivec.h>
54#include <powerpc/pcb.h>
55#include <powerpc/psl.h>
56
57/* Assert that the sizes of these two structures are multiples of 16. */
58CTASSERT((sizeof(siginfo_t) & (CALLFRAMELEN-1)) == 0);
59CTASSERT((sizeof(ucontext_t) & (CALLFRAMELEN-1)) == 0);
60
61/*
62 * Send a signal to process.
63 */
64void
65sendsig_siginfo(const ksiginfo_t *ksi, const sigset_t *mask)
66{
67	struct lwp * const l = curlwp;
68	struct proc * const p = l->l_proc;
69	struct trapframe * const tf = l->l_md.md_utf;
70	stack_t * const ss = &l->l_sigstk;
71	const struct sigact_sigdesc * const sd =
72	    &p->p_sigacts->sa_sigdesc[ksi->ksi_signo];
73	/* save handler before sendsig_reset trashes it! */
74	const void * const handler = sd->sd_sigact.sa_handler;
75	ucontext_t uc;
76	vaddr_t sp, sip, ucp;
77	int onstack, error;
78
79	/* Do we need to jump onto the signal stack? */
80	onstack = (ss->ss_flags & (SS_DISABLE | SS_ONSTACK)) == 0 &&
81	    (sd->sd_sigact.sa_flags & SA_ONSTACK) != 0;
82
83	/* Find top of stack.  */
84	sp = (onstack ? (vaddr_t)ss->ss_sp + ss->ss_size : tf->tf_fixreg[1]);
85
86	/* Ensure it is aligned. */
87	sp &= ~(CALLFRAMELEN-1);
88
89	/* Allocate space for the ucontext.  */
90	sp -= sizeof(ucontext_t);
91
92	/* Allocate space for the siginfo.  */
93	sp -= sizeof(siginfo_t);
94
95#if 0	/* Not needed; see CTASSERTs above. */
96	/* Align it again. */
97	sp &= ~(CALLFRAMELEN-1);
98#endif
99
100	sip = sp;
101	ucp = sp + sizeof(siginfo_t);
102
103	KASSERT((sip & (CALLFRAMELEN-1)) == 0);
104	KASSERT((ucp & (CALLFRAMELEN-1)) == 0);
105
106	/*
107	 * Now allocate space for a call frame, so that there's
108	 * space for the ABI-mandated stack linkage area in the
109	 * event the signal handler calls a another function.
110	 */
111	sp -= CALLFRAMELEN;
112
113	/* Save register context. */
114	memset(&uc, 0, sizeof(uc));
115	uc.uc_flags = _UC_SIGMASK;
116	uc.uc_flags |= (ss->ss_flags & SS_ONSTACK) ?
117	    _UC_SETSTACK : _UC_CLRSTACK;
118	uc.uc_sigmask = *mask;
119	uc.uc_link = l->l_ctxlink;
120	sendsig_reset(l, ksi->ksi_signo);
121	mutex_exit(p->p_lock);
122	cpu_getmcontext(l, &uc.uc_mcontext, &uc.uc_flags);
123
124	/*
125	 * Copy the siginfo and ucontext onto the user's stack.
126	 */
127	error = (copyout(&ksi->ksi_info, (void *)sip, sizeof(ksi->ksi_info)) != 0 ||
128	    copyout(&uc, (void *)ucp, sizeof(uc)) != 0);
129	mutex_enter(p->p_lock);
130
131	if (error) {
132		/*
133		 * Process has trashed its stack; give it an illegal
134		 * instruction to halt it in its tracks.
135		 */
136		sigexit(l, SIGILL);
137		/* NOTREACHED */
138	}
139
140	/*
141	 * Build context to run handler in.  Note the trampoline version
142	 * numbers are coordinated with machine-dependent code in libc.
143	 */
144	switch (sd->sd_vers) {
145	case __SIGTRAMP_SIGINFO_VERSION:	/* siginfo sigtramp */
146		tf->tf_fixreg[1]  = (register_t)sp;
147		tf->tf_fixreg[3]  = (register_t)ksi->ksi_signo;
148		tf->tf_fixreg[4]  = (register_t)sip;
149		tf->tf_fixreg[5]  = (register_t)ucp;
150		/* Preserve ucp across call to signal function */
151		tf->tf_fixreg[30] = (register_t)ucp;
152		tf->tf_lr         = (register_t)sd->sd_tramp;
153		tf->tf_srr0       = (register_t)handler;
154		break;
155
156	default:
157		goto nosupport;
158	}
159
160	/* Remember that we're now on the signal stack. */
161	if (onstack)
162		ss->ss_flags |= SS_ONSTACK;
163	return;
164
165 nosupport:
166	/* Don't know what trampoline version; kill it. */
167	printf("sendsig_siginfo(sig %d): bad version %d\n",
168	    ksi->ksi_signo, sd->sd_vers);
169	sigexit(l, SIGILL);
170	/* NOTREACHED */
171}
172
173void
174cpu_getmcontext(struct lwp *l, mcontext_t *mcp, unsigned int *flagp)
175{
176	const struct trapframe * const tf = l->l_md.md_utf;
177	__greg_t * const gr = mcp->__gregs;
178#if defined(PPC_HAVE_FPU)
179	struct pcb * const pcb = lwp_getpcb(l);
180#endif
181
182	/* Save GPR context. */
183	(void)memcpy(gr, &tf->tf_fixreg, 32 * sizeof (gr[0])); /* GR0-31 */
184	gr[_REG_CR]  = tf->tf_cr;
185	gr[_REG_LR]  = tf->tf_lr;
186	gr[_REG_PC]  = tf->tf_srr0;
187	gr[_REG_MSR] = tf->tf_srr1 & PSL_USERSRR1;
188#ifdef PPC_HAVE_FPU
189	gr[_REG_MSR] |= pcb->pcb_flags & (PCB_FE0|PCB_FE1);
190#endif
191	gr[_REG_CTR] = tf->tf_ctr;
192	gr[_REG_XER] = tf->tf_xer;
193#ifdef PPC_OEA
194	gr[_REG_MQ]  = tf->tf_mq;
195#else
196	gr[_REG_MQ]  = 0;
197#endif
198
199	*flagp |= _UC_CPU;
200	*flagp |= _UC_TLSBASE;
201
202#ifdef PPC_HAVE_FPU
203	/* Save FPU context, if any. */
204	if (!fpu_save_to_mcontext(l, mcp, flagp))
205#endif
206		memset(&mcp->__fpregs, 0, sizeof(mcp->__fpregs));
207
208#if defined(ALTIVEC) || defined(PPC_HAVE_SPE)
209	/* Save vector context, if any. */
210	if (!vec_save_to_mcontext(l, mcp, flagp))
211#endif
212		memset(&mcp->__vrf, 0, sizeof (mcp->__vrf));
213}
214
215int
216cpu_mcontext_validate(struct lwp *l, const mcontext_t *mcp)
217{
218	return 0;
219}
220
221int
222cpu_setmcontext(struct lwp *l, const mcontext_t *mcp, unsigned int flags)
223{
224	struct trapframe * const tf = l->l_md.md_utf;
225	const __greg_t * const gr = mcp->__gregs;
226	struct proc * const p = l->l_proc;
227	int error;
228
229	/* Restore GPR context, if any. */
230	if (flags & _UC_CPU) {
231		error = cpu_mcontext_validate(l, mcp);
232		if (error)
233			return error;
234
235#ifdef PPC_HAVE_FPU
236		/*
237		 * Always save the FP exception mode in the PCB.
238		 */
239		struct pcb * const pcb = lwp_getpcb(l);
240		pcb->pcb_flags &= ~(PCB_FE0|PCB_FE1);
241		pcb->pcb_flags |= gr[_REG_MSR] & (PCB_FE0|PCB_FE1);
242#endif
243
244		/*
245		 * R2 is the TLS register so avoid updating it here.
246		 */
247
248		__greg_t save_r2 = tf->tf_fixreg[_REG_R2];
249		(void)memcpy(&tf->tf_fixreg, gr, 32 * sizeof (gr[0]));
250		tf->tf_fixreg[_REG_R2] = save_r2;
251		tf->tf_cr   = gr[_REG_CR];
252		tf->tf_lr   = gr[_REG_LR];
253		tf->tf_srr0 = gr[_REG_PC];
254
255		/*
256		 * Accept all user-settable bits without complaint;
257		 * userland should not need to know the machine-specific
258		 * MSR value.
259		 */
260		tf->tf_srr1 = (gr[_REG_MSR] & PSL_USERMOD) | PSL_USERSET;
261		tf->tf_ctr  = gr[_REG_CTR];
262		tf->tf_xer  = gr[_REG_XER];
263#ifdef PPC_OEA
264		tf->tf_mq = gr[_REG_MQ];
265#endif
266	}
267
268	if (flags & _UC_TLSBASE)
269		lwp_setprivate(l, (void *)(uintptr_t)gr[_REG_R2]);
270
271#ifdef PPC_HAVE_FPU
272	/* Restore FPU context, if any. */
273	if (flags & _UC_FPU)
274		fpu_restore_from_mcontext(l, mcp);
275#endif
276
277#ifdef ALTIVEC
278	/* Restore AltiVec context, if any. */
279	if (flags & _UC_POWERPC_VEC)
280		vec_restore_from_mcontext(l, mcp);
281#endif
282
283#ifdef PPC_HAVE_SPE
284	/* Restore SPE context, if any. */
285	if (flags & _UC_POWERPC_SPE)
286		vec_restore_from_mcontext(l, mcp);
287#endif
288
289	mutex_enter(p->p_lock);
290	if (flags & _UC_SETSTACK)
291		l->l_sigstk.ss_flags |= SS_ONSTACK;
292	if (flags & _UC_CLRSTACK)
293		l->l_sigstk.ss_flags &= ~SS_ONSTACK;
294	mutex_exit(p->p_lock);
295
296	return (0);
297}
298
299int
300cpu_lwp_setprivate(lwp_t *l, void *addr)
301{
302	struct trapframe * const tf = l->l_md.md_utf;
303
304	tf->tf_fixreg[_REG_R2] = (register_t)addr;
305
306	return 0;
307}
308