1 /* Low level DECstation interface to ptrace, for GDB when running native.
2    Copyright 1988, 1989, 1991, 1992, 1993, 1995, 1996, 1999, 2000, 2001
3    Free Software Foundation, Inc.
4    Contributed by Alessandro Forin(af@cs.cmu.edu) at CMU
5    and by Per Bothner(bothner@cs.wisc.edu) at U.Wisconsin.
6 
7    This file is part of GDB.
8 
9    This program is free software; you can redistribute it and/or modify
10    it under the terms of the GNU General Public License as published by
11    the Free Software Foundation; either version 2 of the License, or
12    (at your option) any later version.
13 
14    This program is distributed in the hope that it will be useful,
15    but WITHOUT ANY WARRANTY; without even the implied warranty of
16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17    GNU General Public License for more details.
18 
19    You should have received a copy of the GNU General Public License
20    along with this program; if not, write to the Free Software
21    Foundation, Inc., 59 Temple Place - Suite 330,
22    Boston, MA 02111-1307, USA.  */
23 
24 #include "defs.h"
25 #include "inferior.h"
26 #include "gdbcore.h"
27 #include "regcache.h"
28 #include <sys/ptrace.h>
29 #include <sys/types.h>
30 #include <sys/param.h>
31 #include <sys/user.h>
32 #undef JB_S0
33 #undef JB_S1
34 #undef JB_S2
35 #undef JB_S3
36 #undef JB_S4
37 #undef JB_S5
38 #undef JB_S6
39 #undef JB_S7
40 #undef JB_SP
41 #undef JB_S8
42 #undef JB_PC
43 #undef JB_SR
44 #undef NJBREGS
45 #include <setjmp.h>		/* For JB_XXX.  */
46 
47 /* Size of elements in jmpbuf */
48 
49 #define JB_ELEMENT_SIZE 4
50 
51 /* Map gdb internal register number to ptrace ``address''.
52    These ``addresses'' are defined in DECstation <sys/ptrace.h> */
53 
54 static int
register_ptrace_addr(int regno)55 register_ptrace_addr (int regno)
56 {
57   return (regno < 32 ? GPR_BASE + regno
58 	  : regno == mips_regnum (current_gdbarch)->pc ? PC
59 	  : regno == mips_regnum (current_gdbarch)->cause ? CAUSE
60 	  : regno == mips_regnum (current_gdbarch)->hi ? MMHI
61 	  : regno == mips_regnum (current_gdbarch)->lo ? MMLO
62 	  : regno == mips_regnum (current_gdbarch)->fp_control_status ? FPC_CSR
63 	  : regno == mips_regnum (current_gdbarch)->fp_implementation_revision ? FPC_EIR
64 	  : regno >= FP0_REGNUM ? FPR_BASE + (regno - FP0_REGNUM)
65 	  : 0);
66 }
67 
68 static void fetch_core_registers (char *, unsigned, int, CORE_ADDR);
69 
70 /* Get all registers from the inferior */
71 
72 void
fetch_inferior_registers(int regno)73 fetch_inferior_registers (int regno)
74 {
75   unsigned int regaddr;
76   char buf[MAX_REGISTER_SIZE];
77   int i;
78   char zerobuf[MAX_REGISTER_SIZE];
79   memset (zerobuf, 0, MAX_REGISTER_SIZE);
80 
81   deprecated_registers_fetched ();
82 
83   for (regno = 1; regno < NUM_REGS; regno++)
84     {
85       regaddr = register_ptrace_addr (regno);
86       for (i = 0; i < DEPRECATED_REGISTER_RAW_SIZE (regno); i += sizeof (int))
87 	{
88 	  *(int *) &buf[i] = ptrace (PT_READ_U, PIDGET (inferior_ptid),
89 				     (PTRACE_ARG3_TYPE) regaddr, 0);
90 	  regaddr += sizeof (int);
91 	}
92       supply_register (regno, buf);
93     }
94 
95   supply_register (ZERO_REGNUM, zerobuf);
96   /* Frame ptr reg must appear to be 0; it is faked by stack handling code. */
97   supply_register (DEPRECATED_FP_REGNUM, zerobuf);
98 }
99 
100 /* Store our register values back into the inferior.
101    If REGNO is -1, do this for all registers.
102    Otherwise, REGNO specifies which register (so we can save time).  */
103 
104 void
store_inferior_registers(int regno)105 store_inferior_registers (int regno)
106 {
107   unsigned int regaddr;
108   char buf[80];
109 
110   if (regno > 0)
111     {
112       if (regno == ZERO_REGNUM || regno == PS_REGNUM
113 	  || regno == mips_regnum (current_gdbarch)->badvaddr
114 	  || regno == mips_regnum (current_gdbarch)->cause
115 	  || regno == mips_regnum (current_gdbarch)->fp_implementation_revision
116 	  || regno == DEPRECATED_FP_REGNUM
117 	  || (regno >= FIRST_EMBED_REGNUM && regno <= LAST_EMBED_REGNUM))
118 	return;
119       regaddr = register_ptrace_addr (regno);
120       errno = 0;
121       ptrace (PT_WRITE_U, PIDGET (inferior_ptid), (PTRACE_ARG3_TYPE) regaddr,
122 	      read_register (regno));
123       if (errno != 0)
124 	{
125 	  sprintf (buf, "writing register number %d", regno);
126 	  perror_with_name (buf);
127 	}
128     }
129   else
130     {
131       for (regno = 0; regno < NUM_REGS; regno++)
132 	store_inferior_registers (regno);
133     }
134 }
135 
136 
137 /* Figure out where the longjmp will land.
138    We expect the first arg to be a pointer to the jmp_buf structure from which
139    we extract the pc (JB_PC) that we will land at.  The pc is copied into PC.
140    This routine returns true on success. */
141 
142 int
get_longjmp_target(CORE_ADDR * pc)143 get_longjmp_target (CORE_ADDR *pc)
144 {
145   CORE_ADDR jb_addr;
146   char *buf;
147 
148   buf = alloca (TARGET_PTR_BIT / TARGET_CHAR_BIT);
149   jb_addr = read_register (A0_REGNUM);
150 
151   if (target_read_memory (jb_addr + JB_PC * JB_ELEMENT_SIZE, buf,
152 			  TARGET_PTR_BIT / TARGET_CHAR_BIT))
153     return 0;
154 
155   *pc = extract_unsigned_integer (buf, TARGET_PTR_BIT / TARGET_CHAR_BIT);
156 
157   return 1;
158 }
159 
160 /* Extract the register values out of the core file and store
161    them where `read_register' will find them.
162 
163    CORE_REG_SECT points to the register values themselves, read into memory.
164    CORE_REG_SIZE is the size of that area.
165    WHICH says which set of registers we are handling (0 = int, 2 = float
166    on machines where they are discontiguous).
167    REG_ADDR is the offset from u.u_ar0 to the register values relative to
168    core_reg_sect.  This is used with old-fashioned core files to
169    locate the registers in a large upage-plus-stack ".reg" section.
170    Original upage address X is at location core_reg_sect+x+reg_addr.
171  */
172 
173 static void
fetch_core_registers(char * core_reg_sect,unsigned core_reg_size,int which,CORE_ADDR reg_addr)174 fetch_core_registers (char *core_reg_sect, unsigned core_reg_size, int which,
175 		      CORE_ADDR reg_addr)
176 {
177   int regno;
178   unsigned int addr;
179   int bad_reg = -1;
180   reg_ptr = -reg_addr;	/* Original u.u_ar0 is -reg_addr. */
181 
182   char zerobuf[MAX_REGISTER_SIZE];
183   memset (zerobuf, 0, MAX_REGISTER_SIZE);
184 
185 
186   /* If u.u_ar0 was an absolute address in the core file, relativize it now,
187      so we can use it as an offset into core_reg_sect.  When we're done,
188      "register 0" will be at core_reg_sect+reg_ptr, and we can use
189      register_addr to offset to the other registers.  If this is a modern
190      core file without a upage, reg_ptr will be zero and this is all a big
191      NOP.  */
192   if (reg_ptr > core_reg_size)
193 #ifdef KERNEL_U_ADDR
194     reg_ptr -= KERNEL_U_ADDR;
195 #else
196     error ("Old mips core file can't be processed on this machine.");
197 #endif
198 
199   for (regno = 0; regno < NUM_REGS; regno++)
200     {
201       addr = register_addr (regno, reg_ptr);
202       if (addr >= core_reg_size)
203 	{
204 	  if (bad_reg < 0)
205 	    bad_reg = regno;
206 	}
207       else
208 	{
209 	  supply_register (regno, core_reg_sect + addr);
210 	}
211     }
212   if (bad_reg >= 0)
213     {
214       error ("Register %s not found in core file.", REGISTER_NAME (bad_reg));
215     }
216   supply_register (ZERO_REGNUM, zerobuf);
217   /* Frame ptr reg must appear to be 0; it is faked by stack handling code. */
218   supply_register (DEPRECATED_FP_REGNUM, zerobuf);
219 }
220 
221 /* Return the address in the core dump or inferior of register REGNO.
222    BLOCKEND is the address of the end of the user structure.  */
223 
224 CORE_ADDR
register_addr(int regno,CORE_ADDR blockend)225 register_addr (int regno, CORE_ADDR blockend)
226 {
227   CORE_ADDR addr;
228 
229   if (regno < 0 || regno >= NUM_REGS)
230     error ("Invalid register number %d.", regno);
231 
232   REGISTER_U_ADDR (addr, blockend, regno);
233 
234   return addr;
235 }
236 
237 
238 /* Register that we are able to handle mips core file formats.
239    FIXME: is this really bfd_target_unknown_flavour? */
240 
241 static struct core_fns mips_core_fns =
242 {
243   bfd_target_unknown_flavour,		/* core_flavour */
244   default_check_format,			/* check_format */
245   default_core_sniffer,			/* core_sniffer */
246   fetch_core_registers,			/* core_read_registers */
247   NULL					/* next */
248 };
249 
250 void
_initialize_core_mips(void)251 _initialize_core_mips (void)
252 {
253   deprecated_add_core_fns (&mips_core_fns);
254 }
255