1 /* DWARF2 EH unwinding support for DragonFly BSD: AMD x86-64 and x86.
2    Copyright (C) 2010 John Marino <draco@marino.st> */
3 
4 /* Do code reading to identify a signal frame, and set the frame
5    state data appropriately.  See unwind-dw2.c for the structs. */
6 
7 #include <sys/types.h>
8 #include <sys/sysctl.h>
9 #include <signal.h>
10 #include <sys/ucontext.h>
11 #include <machine/sigframe.h>
12 
13 
14 #define REG_NAME(reg)	sf_uc.uc_mcontext.mc_## reg
15 
16 #ifdef __x86_64__
17 #define MD_FALLBACK_FRAME_STATE_FOR x86_64_dragonfly_fallback_frame_state
18 
19 
20 static void
x86_64_sigtramp_range(unsigned char ** start,unsigned char ** end)21 x86_64_sigtramp_range (unsigned char **start, unsigned char **end)
22 {
23   unsigned long ps_strings;
24   int mib[2];
25   size_t len;
26 
27   mib[0] = CTL_KERN;
28   mib[1] = KERN_PS_STRINGS;
29   len = sizeof (ps_strings);
30   sysctl (mib, 2, &ps_strings, &len, NULL, 0);
31 
32   *start = (unsigned char *)ps_strings - 32;
33   *end   = (unsigned char *)ps_strings;
34 }
35 
36 
37 static _Unwind_Reason_Code
x86_64_dragonfly_fallback_frame_state(struct _Unwind_Context * context,_Unwind_FrameState * fs)38 x86_64_dragonfly_fallback_frame_state
39 (struct _Unwind_Context *context, _Unwind_FrameState *fs)
40 {
41   unsigned char *pc = context->ra;
42   unsigned char *sigtramp_start, *sigtramp_end;
43   struct sigframe *sf;
44   long new_cfa;
45 
46   x86_64_sigtramp_range(&sigtramp_start, &sigtramp_end);
47   if (pc >= sigtramp_end || pc < sigtramp_start)
48     return _URC_END_OF_STACK;
49 
50   sf = (struct sigframe *) context->cfa;
51   new_cfa = sf->REG_NAME(rsp);
52   fs->regs.cfa_how = CFA_REG_OFFSET;
53   /* Register 7 is rsp  */
54   fs->regs.cfa_reg = 7;
55   fs->regs.cfa_offset = new_cfa - (long) context->cfa;
56 
57   /* The SVR4 register numbering macros aren't usable in libgcc.  */
58   fs->regs.reg[0].how = REG_SAVED_OFFSET;
59   fs->regs.reg[0].loc.offset = (long)&sf->REG_NAME(rax) - new_cfa;
60   fs->regs.reg[1].how = REG_SAVED_OFFSET;
61   fs->regs.reg[1].loc.offset = (long)&sf->REG_NAME(rdx) - new_cfa;
62   fs->regs.reg[2].how = REG_SAVED_OFFSET;
63   fs->regs.reg[2].loc.offset = (long)&sf->REG_NAME(rcx) - new_cfa;
64   fs->regs.reg[3].how = REG_SAVED_OFFSET;
65   fs->regs.reg[3].loc.offset = (long)&sf->REG_NAME(rbx) - new_cfa;
66   fs->regs.reg[4].how = REG_SAVED_OFFSET;
67   fs->regs.reg[4].loc.offset = (long)&sf->REG_NAME(rsi) - new_cfa;
68   fs->regs.reg[5].how = REG_SAVED_OFFSET;
69   fs->regs.reg[5].loc.offset = (long)&sf->REG_NAME(rdi) - new_cfa;
70   fs->regs.reg[6].how = REG_SAVED_OFFSET;
71   fs->regs.reg[6].loc.offset = (long)&sf->REG_NAME(rbp) - new_cfa;
72   fs->regs.reg[8].how = REG_SAVED_OFFSET;
73   fs->regs.reg[8].loc.offset = (long)&sf->REG_NAME(r8) - new_cfa;
74   fs->regs.reg[9].how = REG_SAVED_OFFSET;
75   fs->regs.reg[9].loc.offset = (long)&sf->REG_NAME(r9) - new_cfa;
76   fs->regs.reg[10].how = REG_SAVED_OFFSET;
77   fs->regs.reg[10].loc.offset = (long)&sf->REG_NAME(r10) - new_cfa;
78   fs->regs.reg[11].how = REG_SAVED_OFFSET;
79   fs->regs.reg[11].loc.offset = (long)&sf->REG_NAME(r11) - new_cfa;
80   fs->regs.reg[12].how = REG_SAVED_OFFSET;
81   fs->regs.reg[12].loc.offset = (long)&sf->REG_NAME(r12) - new_cfa;
82   fs->regs.reg[13].how = REG_SAVED_OFFSET;
83   fs->regs.reg[13].loc.offset = (long)&sf->REG_NAME(r13) - new_cfa;
84   fs->regs.reg[14].how = REG_SAVED_OFFSET;
85   fs->regs.reg[14].loc.offset = (long)&sf->REG_NAME(r14) - new_cfa;
86   fs->regs.reg[15].how = REG_SAVED_OFFSET;
87   fs->regs.reg[15].loc.offset = (long)&sf->REG_NAME(r15) - new_cfa;
88   fs->regs.reg[16].how = REG_SAVED_OFFSET;
89   fs->regs.reg[16].loc.offset = (long)&sf->REG_NAME(rip) - new_cfa;
90   fs->retaddr_column = 16;
91   fs->signal_frame = 1;
92   return _URC_NO_REASON;
93 }
94 
95 #else /* Next section is for i386  */
96 
97 #define MD_FALLBACK_FRAME_STATE_FOR x86_dragonfly_fallback_frame_state
98 
99 
100 static void
x86_sigtramp_range(unsigned char ** start,unsigned char ** end)101 x86_sigtramp_range (unsigned char **start, unsigned char **end)
102 {
103   unsigned long ps_strings;
104   int mib[2];
105   size_t len;
106 
107   mib[0] = CTL_KERN;
108   mib[1] = KERN_PS_STRINGS;
109   len = sizeof (ps_strings);
110   sysctl (mib, 2, &ps_strings, &len, NULL, 0);
111 
112   *start = (unsigned char *)ps_strings - 128;
113   *end   = (unsigned char *)ps_strings;
114 }
115 
116 
117 static _Unwind_Reason_Code
x86_dragonfly_fallback_frame_state(struct _Unwind_Context * context,_Unwind_FrameState * fs)118 x86_dragonfly_fallback_frame_state
119 (struct _Unwind_Context *context, _Unwind_FrameState *fs)
120 {
121   unsigned char *pc = context->ra;
122   unsigned char *sigtramp_start, *sigtramp_end;
123   struct sigframe *sf;
124   long new_cfa;
125 
126   x86_sigtramp_range(&sigtramp_start, &sigtramp_end);
127 
128   if (pc >= sigtramp_end || pc < sigtramp_start)
129     return _URC_END_OF_STACK;
130 
131   sf = (struct sigframe *) context->cfa;
132   new_cfa = sf->REG_NAME(esp);
133   fs->regs.cfa_how = CFA_REG_OFFSET;
134   fs->regs.cfa_reg = 4;
135   fs->regs.cfa_offset = new_cfa - (long) context->cfa;
136 
137   /* The SVR4 register numbering macros aren't usable in libgcc.  */
138   fs->regs.reg[0].how = REG_SAVED_OFFSET;
139   fs->regs.reg[0].loc.offset = (long)&sf->REG_NAME(eax) - new_cfa;
140   fs->regs.reg[3].how = REG_SAVED_OFFSET;
141   fs->regs.reg[3].loc.offset = (long)&sf->REG_NAME(ebx) - new_cfa;
142   fs->regs.reg[1].how = REG_SAVED_OFFSET;
143   fs->regs.reg[1].loc.offset = (long)&sf->REG_NAME(ecx) - new_cfa;
144   fs->regs.reg[2].how = REG_SAVED_OFFSET;
145   fs->regs.reg[2].loc.offset = (long)&sf->REG_NAME(edx) - new_cfa;
146   fs->regs.reg[6].how = REG_SAVED_OFFSET;
147   fs->regs.reg[6].loc.offset = (long)&sf->REG_NAME(esi) - new_cfa;
148   fs->regs.reg[7].how = REG_SAVED_OFFSET;
149   fs->regs.reg[7].loc.offset = (long)&sf->REG_NAME(edi) - new_cfa;
150   fs->regs.reg[5].how = REG_SAVED_OFFSET;
151   fs->regs.reg[5].loc.offset = (long)&sf->REG_NAME(ebp) - new_cfa;
152   fs->regs.reg[8].how = REG_SAVED_OFFSET;
153   fs->regs.reg[8].loc.offset = (long)&sf->REG_NAME(eip) - new_cfa;
154   fs->retaddr_column = 8;
155   fs->signal_frame = 1;
156   return _URC_NO_REASON;
157 }
158 #endif /* ifdef __x86_64__  */
159