gdb/gdbserver/linux-i386-ipa.c - gdb

Global variables defined

Data types defined

Functions defined

Macros defined

Source code

  1. /* GNU/Linux/x86 specific low level interface, for the in-process
  2.    agent library for GDB.

  4.    Copyright (C) 2010-2015 Free Software Foundation, Inc.

  6.    This file is part of GDB.

  8.    This program is free software; you can redistribute it and/or modify
  9.    it under the terms of the GNU General Public License as published by
  10.    the Free Software Foundation; either version 3 of the License, or
  11.    (at your option) any later version.

  13.    This program is distributed in the hope that it will be useful,
  14.    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15.    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16.    GNU General Public License for more details.

  18.    You should have received a copy of the GNU General Public License
  19.    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

  21. #include "server.h"
  22. #include <stdint.h>
  23. #include <sys/mman.h>
  24. #include "tracepoint.h"

  26. /* GDB register numbers.  */

  28. ‌enum i386_gdb_regnum
  29. {
  30.   I386_EAX_REGNUM,                /* %eax */
  31.   I386_ECX_REGNUM,                /* %ecx */
  32.   I386_EDX_REGNUM,                /* %edx */
  33.   I386_EBX_REGNUM,                /* %ebx */
  34.   I386_ESP_REGNUM,                /* %esp */
  35.   I386_EBP_REGNUM,                /* %ebp */
  36.   I386_ESI_REGNUM,                /* %esi */
  37.   I386_EDI_REGNUM,                /* %edi */
  38.   I386_EIP_REGNUM,                /* %eip */
  39.   I386_EFLAGS_REGNUM,                /* %eflags */
  40.   I386_CS_REGNUM,                /* %cs */
  41.   I386_SS_REGNUM,                /* %ss */
  42.   I386_DS_REGNUM,                /* %ds */
  43.   I386_ES_REGNUM,                /* %es */
  44.   I386_FS_REGNUM,                /* %fs */
  45.   I386_GS_REGNUM,                /* %gs */
  46.   I386_ST0_REGNUM                /* %st(0) */
  47. };

  49. ‌#define i386_num_regs 16

  51. /* Defined in auto-generated file i386-linux.c.  */
  52. void init_registers_i386_linux (void);
  53. extern const struct target_desc *tdesc_i386_linux;

  55. ‌#define FT_CR_EAX 15
  56. ‌#define FT_CR_ECX 14
  57. ‌#define FT_CR_EDX 13
  58. ‌#define FT_CR_EBX 12
  59. ‌#define FT_CR_UESP 11
  60. ‌#define FT_CR_EBP 10
  61. ‌#define FT_CR_ESI 9
  62. ‌#define FT_CR_EDI 8
  63. ‌#define FT_CR_EIP 7
  64. ‌#define FT_CR_EFL 6
  65. ‌#define FT_CR_DS 5
  66. ‌#define FT_CR_ES 4
  67. ‌#define FT_CR_FS 3
  68. ‌#define FT_CR_GS 2
  69. ‌#define FT_CR_SS 1
  70. ‌#define FT_CR_CS 0

  72. /* Mapping between the general-purpose registers in jump tracepoint
  73.    format and GDB's register array layout.  */

  75. ‌static const int i386_ft_collect_regmap[] =
  76. {
  77.   FT_CR_EAX * 4, FT_CR_ECX * 4, FT_CR_EDX * 4, FT_CR_EBX * 4,
  78.   FT_CR_UESP * 4, FT_CR_EBP * 4, FT_CR_ESI * 4, FT_CR_EDI * 4,
  79.   FT_CR_EIP * 4, FT_CR_EFL * 4, FT_CR_CS * 4, FT_CR_SS * 4,
  80.   FT_CR_DS * 4, FT_CR_ES * 4, FT_CR_FS * 4, FT_CR_GS * 4
  81. };

  83. void
  84. ‌supply_fast_tracepoint_registers (struct regcache *regcache,
  85.                                   const unsigned char *buf)
  86. {
  87.   int i;

  89.   for (i = 0; i < i386_num_regs; i++)
  90.     {
  91.       int regval;

  93.       if (i >= I386_CS_REGNUM && i <= I386_GS_REGNUM)
  94.         regval = *(short *) (((char *) buf) + i386_ft_collect_regmap[i]);
  95.       else
  96.         regval = *(int *) (((char *) buf) + i386_ft_collect_regmap[i]);

  98.       supply_register (regcache, i, &regval);
  99.     }
  100. }

  102. ULONGEST __attribute__ ((visibility("default"), used))
  103. ‌gdb_agent_get_raw_reg (unsigned char *raw_regs, int regnum)
  104. {
  105.   /* This should maybe be allowed to return an error code, or perhaps
  106.      better, have the emit_reg detect this, and emit a constant zero,
  107.      or something.  */

  109.   if (regnum > i386_num_regs)
  110.     return 0;
  111.   else if (regnum >= I386_CS_REGNUM && regnum <= I386_GS_REGNUM)
  112.     return *(short *) (raw_regs + i386_ft_collect_regmap[regnum]);
  113.   else
  114.     return *(int *) (raw_regs + i386_ft_collect_regmap[regnum]);
  115. }

  117. #ifdef HAVE_UST

  119. #include <ust/processor.h>

  121. /* "struct registers" is the UST object type holding the registers at
  122.    the time of the static tracepoint marker call.  This doesn't
  123.    contain EIP, but we know what it must have been (the marker
  124.    address).  */

  126. ‌#define ST_REGENTRY(REG)                        \
  127.   {                                                \
  128.     offsetof (struct registers, REG),                \
  129.     sizeof (((struct registers *) NULL)->REG)        \
  130.   }

  132. static struct
  133. {
  134.   int offset;
  135.   int size;
  136. ‌} i386_st_collect_regmap[] =
  137.   {
  138.     ST_REGENTRY(eax),
  139.     ST_REGENTRY(ecx),
  140.     ST_REGENTRY(edx),
  141.     ST_REGENTRY(ebx),
  142.     ST_REGENTRY(esp),
  143.     ST_REGENTRY(ebp),
  144.     ST_REGENTRY(esi),
  145.     ST_REGENTRY(edi),
  146.     { -1, 0 }, /* eip */
  147.     ST_REGENTRY(eflags),
  148.     ST_REGENTRY(cs),
  149.     ST_REGENTRY(ss),
  150.   };

  152. ‌#define i386_NUM_ST_COLLECT_GREGS \
  153.   (sizeof (i386_st_collect_regmap) / sizeof (i386_st_collect_regmap[0]))

  155. void
  156. ‌supply_static_tracepoint_registers (struct regcache *regcache,
  157.                                     const unsigned char *buf,
  158.                                     CORE_ADDR pc)
  159. {
  160.   int i;
  161.   unsigned int newpc = pc;

  163.   supply_register (regcache, I386_EIP_REGNUM, &newpc);

  165.   for (i = 0; i < i386_NUM_ST_COLLECT_GREGS; i++)
  166.     if (i386_st_collect_regmap[i].offset != -1)
  167.       {
  168.         switch (i386_st_collect_regmap[i].size)
  169.           {
  170.           case 4:
  171.             supply_register (regcache, i,
  172.                              ((char *) buf)
  173.                              + i386_st_collect_regmap[i].offset);
  174.             break;
  175.           case 2:
  176.             {
  177.               unsigned long reg
  178.                 = * (short *) (((char *) buf)
  179.                                + i386_st_collect_regmap[i].offset);
  180.               reg &= 0xffff;
  181.               supply_register (regcache, i, &reg);
  182.             }
  183.             break;
  184.           default:
  185.             internal_error (__FILE__, __LINE__, "unhandled register size: %d",
  186.                             i386_st_collect_regmap[i].size);
  187.           }
  188.       }
  189. }

  191. #endif /* HAVE_UST */


  194. /* This is only needed because reg-i386-linux-lib.o references it.  We
  195.    may use it proper at some point.  */
  196. ‌const char *gdbserver_xmltarget;

  198. /* Attempt to allocate memory for trampolines in the first 64 KiB of
  199.    memory to enable smaller jump patches.  */

  201. static void
  202. ‌initialize_fast_tracepoint_trampoline_buffer (void)
  203. {
  204.   const CORE_ADDR buffer_end = 64 * 1024;
  205.   /* Ensure that the buffer will be at least 1 KiB in size, which is
  206.      enough space for over 200 fast tracepoints.  */
  207.   const int min_buffer_size = 1024;
  208.   char buf[IPA_BUFSIZ];
  209.   CORE_ADDR mmap_min_addr = buffer_end + 1;
  210.   ULONGEST buffer_size;
  211.   FILE *f = fopen ("/proc/sys/vm/mmap_min_addr", "r");

  213.   if (!f)
  214.     {
  215.       snprintf (buf, sizeof (buf), "mmap_min_addr open failed: %s",
  216.                 strerror (errno));
  217.       set_trampoline_buffer_space (0, 0, buf);
  218.       return;
  219.     }

  221.   if (fgets (buf, IPA_BUFSIZ, f))
  222.     sscanf (buf, "%llu", &mmap_min_addr);

  224.   fclose (f);

  226.   buffer_size = buffer_end - mmap_min_addr;

  228.   if (buffer_size >= min_buffer_size)
  229.     {
  230.       if (mmap ((void *) (uintptr_t) mmap_min_addr, buffer_size,
  231.                 PROT_READ | PROT_EXEC | PROT_WRITE,
  232.                 MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
  233.                 -1, 0)
  234.           != MAP_FAILED)
  235.         set_trampoline_buffer_space (mmap_min_addr, buffer_end, NULL);
  236.       else
  237.         {
  238.           snprintf (buf, IPA_BUFSIZ, "low-64K-buffer mmap() failed: %s",
  239.                     strerror (errno));
  240.           set_trampoline_buffer_space (0, 0, buf);
  241.         }
  242.     }
  243.   else
  244.     {
  245.       snprintf (buf, IPA_BUFSIZ, "mmap_min_addr is %d, must be %d or less",
  246.                 (int) mmap_min_addr, (int) buffer_end - min_buffer_size);
  247.       set_trampoline_buffer_space (0, 0, buf);
  248.     }
  249. }

  251. void
  252. ‌initialize_low_tracepoint (void)
  253. {
  254.   init_registers_i386_linux ();
  255.   ipa_tdesc = tdesc_i386_linux;
  256.   initialize_fast_tracepoint_trampoline_buffer ();
  257. }