2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2003 Marcel Moolenaar
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
32 #include <sys/types.h>
33 #include <sys/ucontext.h>
38 typedef void (*handler_t)(uint64_t, uint64_t, uint64_t);
41 static void sigctx_wrapper(ucontext_t *ucp, handler_t func, uint64_t *args);
43 __weak_reference(__signalcontext, signalcontext);
46 __signalcontext(ucontext_t *ucp, int sig, __sighandler_t *func)
53 /* Bail out if we don't have a valid ucontext pointer. */
58 * Build a signal frame and copy the arguments of signal handler
59 * 'func' onto the stack and do the funky stack alignment.
60 * This means that we need an 8-byte-odd alignment since the ABI expects
61 * the return address to be pushed, thus breaking the 16 byte alignment.
63 sp = (ucp->uc_mcontext.mc_rsp - 128 - sizeof(ucontext_t)) & ~15UL;
64 sig_uc = (ucontext_t *)sp;
65 bcopy(ucp, sig_uc, sizeof(*sig_uc));
66 sp = (sp - sizeof(siginfo_t)) & ~15UL;
67 sig_si = (siginfo_t *)sp;
68 bzero(sig_si, sizeof(*sig_si));
69 sig_si->si_signo = sig;
70 sp -= 3 * sizeof(uint64_t);
71 args = (uint64_t *)sp;
73 args[1] = (intptr_t)sig_si;
74 args[2] = (intptr_t)sig_uc;
78 * Setup the ucontext of the signal handler.
80 bzero(&ucp->uc_mcontext, sizeof(ucp->uc_mcontext));
81 ucp->uc_mcontext.mc_fpformat = _MC_FPFMT_NODEV;
82 ucp->uc_mcontext.mc_ownedfp = _MC_FPOWNED_NONE;
83 ucp->uc_link = sig_uc;
84 sigdelset(&ucp->uc_sigmask, sig);
86 ucp->uc_mcontext.mc_len = sizeof(mcontext_t);
87 ucp->uc_mcontext.mc_rdi = (register_t)ucp;
88 ucp->uc_mcontext.mc_rsi = (register_t)func;
89 ucp->uc_mcontext.mc_rdx = (register_t)args;
90 ucp->uc_mcontext.mc_rbp = (register_t)sp;
91 ucp->uc_mcontext.mc_rbx = (register_t)sp;
92 ucp->uc_mcontext.mc_rsp = (register_t)sp;
93 ucp->uc_mcontext.mc_rip = (register_t)sigctx_wrapper;
98 sigctx_wrapper(ucontext_t *ucp, handler_t func, uint64_t *args)
101 (*func)(args[0], args[1], args[2]);
102 if (ucp->uc_link == NULL)
104 setcontext((const ucontext_t *)ucp->uc_link);
105 /* should never get here */