1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * S I G T R A M P *
6 * *
7 * Asm Implementation File *
8 * *
9 * Copyright (C) 2011-2015, Free Software Foundation, Inc. *
10 * *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 3, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. *
17 * *
18 * As a special exception under Section 7 of GPL version 3, you are granted *
19 * additional permissions described in the GCC Runtime Library Exception, *
20 * version 3.1, as published by the Free Software Foundation. *
21 * *
22 * In particular, you can freely distribute your programs built with the *
23 * GNAT Pro compiler, including any required library run-time units, using *
24 * any licensing terms of your choosing. See the AdaCore Software License *
25 * for full details. *
26 * *
27 * GNAT was originally developed by the GNAT team at New York University. *
28 * Extensive contributions were provided by Ada Core Technologies Inc. *
29 * *
30 ****************************************************************************/
31
32 /**************************************************
33 * VxWorks version of the __gnat_sigtramp service *
34 **************************************************/
35
36 #include "sigtramp.h"
37 /* See sigtramp.h for a general explanation of functionality. */
38
39 #include <vxWorks.h>
40 #include <arch/../regs.h>
41 #ifndef __RTP__
42 #include <sigLib.h>
43 #else
44 #include <signal.h>
45 #include <regs.h>
46
47 typedef struct mcontext
48 {
49 REG_SET regs;
50 } mcontext_t;
51
52 typedef struct ucontext
53 {
54 mcontext_t uc_mcontext; /* register set */
55 struct ucontext * uc_link; /* not used */
56 sigset_t uc_sigmask; /* set of signals blocked */
57 stack_t uc_stack; /* stack of context signaled */
58 } ucontext_t;
59 #endif
60
61 /* ----------------------
62 -- General comments --
63 ----------------------
64
65 Stubs are generated from toplevel asms and .cfi directives, much simpler
66 to use and check for correctness than manual encodings of CFI byte
67 sequences. The general idea is to establish CFA as sigcontext->sc_pregs
68 (for DKM) and mcontext (for RTP) and state where to find the registers as
69 offsets from there.
70
71 As of today, we support a stub providing CFI info for common
72 registers (GPRs, LR, ...). We might need variants with support for floating
73 point or altivec registers as well at some point.
74
75 Checking which variant should apply and getting at sc_pregs / mcontext
76 is simpler to express in C (we can't use offsetof in toplevel asms and
77 hardcoding constants is not workable with the flurry of VxWorks variants),
78 so this is the choice for our toplevel interface.
79
80 Note that the registers we "restore" here are those to which we have
81 direct access through the system sigcontext structure, which includes
82 only a partial set of the non-volatiles ABI-wise. */
83
84 /* -------------------------------------------
85 -- Prototypes for our internal asm stubs --
86 -------------------------------------------
87
88 Eventhough our symbols will remain local, the prototype claims "extern"
89 and not "static" to prevent compiler complaints about a symbol used but
90 never defined. */
91
92 /* sigtramp stub providing CFI info for common registers. */
93
94 extern void __gnat_sigtramp_common
95 (int signo, void *siginfo, void *sigcontext,
96 __sigtramphandler_t * handler, void * sc_pregs);
97
98
99 /* -------------------------------------
100 -- Common interface implementation --
101 -------------------------------------
102
103 We enforce optimization to minimize the overhead of the extra layer. */
104
105 void __gnat_sigtramp (int signo, void *si, void *sc,
106 __sigtramphandler_t * handler)
107 __attribute__((optimize(2)));
108
__gnat_sigtramp(int signo,void * si,void * sc,__sigtramphandler_t * handler)109 void __gnat_sigtramp (int signo, void *si, void *sc,
110 __sigtramphandler_t * handler)
111 {
112 #ifdef __RTP__
113 mcontext_t *mcontext = &((ucontext_t *) sc)->uc_mcontext;
114
115 /* Pass MCONTEXT in the fifth position so that the assembly code can find
116 it at the same stack location or in the same register as SC_PREGS. */
117 __gnat_sigtramp_common (signo, si, mcontext, handler, mcontext);
118 #else
119 struct sigcontext * sctx = (struct sigcontext *) sc;
120
121 __gnat_sigtramp_common (signo, si, sctx, handler, sctx->sc_pregs);
122 #endif
123 }
124
125 /* Include the target specific bits. */
126 #include "sigtramp-vxworks-target.inc"
127
128 /* sigtramp stub for common registers. */
129
130 #define TRAMP_COMMON __gnat_sigtramp_common
131
132 asm (SIGTRAMP_START(TRAMP_COMMON));
133 asm (CFI_DEF_CFA);
134 asm (CFI_COMMON_REGS);
135 asm (SIGTRAMP_BODY);
136 asm (SIGTRAMP_END(TRAMP_COMMON));
137
138
139