gdb/mipsnbsd-tdep.c - gdb

Global variables defined

Functions defined

Macros defined

Source code

  1. /* Target-dependent code for NetBSD/mips.

  3.    Copyright (C) 2002-2015 Free Software Foundation, Inc.

  5.    Contributed by Wasabi Systems, Inc.

  7.    This file is part of GDB.

  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 3 of the License, or
  12.    (at your option) any later version.

  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.

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

  22. #include "defs.h"
  23. #include "gdbcore.h"
  24. #include "regcache.h"
  25. #include "regset.h"
  26. #include "target.h"
  27. #include "value.h"
  28. #include "osabi.h"

  30. #include "nbsd-tdep.h"
  31. #include "mipsnbsd-tdep.h"
  32. #include "mips-tdep.h"

  34. #include "solib-svr4.h"

  36. /* Shorthand for some register numbers used below.  */
  37. ‌#define MIPS_PC_REGNUM  MIPS_EMBED_PC_REGNUM
  38. ‌#define MIPS_FP0_REGNUM MIPS_EMBED_FP0_REGNUM
  39. ‌#define MIPS_FSR_REGNUM MIPS_EMBED_FP0_REGNUM + 32

  41. /* Core file support.  */

  43. /* Number of registers in `struct reg' from <machine/reg.h>.  */
  44. ‌#define MIPSNBSD_NUM_GREGS        38

  46. /* Number of registers in `struct fpreg' from <machine/reg.h>.  */
  47. ‌#define MIPSNBSD_NUM_FPREGS        33

  49. /* Supply register REGNUM from the buffer specified by FPREGS and LEN
  50.    in the floating-point register set REGSET to register cache
  51.    REGCACHE.  If REGNUM is -1, do this for all registers in REGSET.  */

  53. static void
  54. ‌mipsnbsd_supply_fpregset (const struct regset *regset,
  55.                           struct regcache *regcache,
  56.                           int regnum, const void *fpregs, size_t len)
  57. {
  58.   size_t regsize = mips_isa_regsize (get_regcache_arch (regcache));
  59.   const char *regs = fpregs;
  60.   int i;

  62.   gdb_assert (len >= MIPSNBSD_NUM_FPREGS * regsize);

  64.   for (i = MIPS_FP0_REGNUM; i <= MIPS_FSR_REGNUM; i++)
  65.     {
  66.       if (regnum == i || regnum == -1)
  67.         regcache_raw_supply (regcache, i,
  68.                              regs + (i - MIPS_FP0_REGNUM) * regsize);
  69.     }
  70. }

  72. /* Supply register REGNUM from the buffer specified by GREGS and LEN
  73.    in the general-purpose register set REGSET to register cache
  74.    REGCACHE.  If REGNUM is -1, do this for all registers in REGSET.  */

  76. static void
  77. ‌mipsnbsd_supply_gregset (const struct regset *regset,
  78.                          struct regcache *regcache, int regnum,
  79.                          const void *gregs, size_t len)
  80. {
  81.   size_t regsize = mips_isa_regsize (get_regcache_arch (regcache));
  82.   const char *regs = gregs;
  83.   int i;

  85.   gdb_assert (len >= MIPSNBSD_NUM_GREGS * regsize);

  87.   for (i = 0; i <= MIPS_PC_REGNUM; i++)
  88.     {
  89.       if (regnum == i || regnum == -1)
  90.         regcache_raw_supply (regcache, i, regs + i * regsize);
  91.     }

  93.   if (len >= (MIPSNBSD_NUM_GREGS + MIPSNBSD_NUM_FPREGS) * regsize)
  94.     {
  95.       regs += MIPSNBSD_NUM_GREGS * regsize;
  96.       len -= MIPSNBSD_NUM_GREGS * regsize;
  97.       mipsnbsd_supply_fpregset (regset, regcache, regnum, regs, len);
  98.     }
  99. }

  101. /* NetBSD/mips register sets.  */

  103. ‌static const struct regset mipsnbsd_gregset =
  104. {
  105.   NULL,
  106.   mipsnbsd_supply_gregset
  107. };

  109. ‌static const struct regset mipsnbsd_fpregset =
  110. {
  111.   NULL,
  112.   mipsnbsd_supply_fpregset
  113. };

  115. /* Iterate over core file register note sections.  */

  117. static void
  118. ‌mipsnbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
  119.                                        iterate_over_regset_sections_cb *cb,
  120.                                        void *cb_data,
  121.                                        const struct regcache *regcache)
  122. {
  123.   size_t regsize = mips_isa_regsize (gdbarch);

  125.   cb (".reg", MIPSNBSD_NUM_GREGS * regsize, &mipsnbsd_gregset,
  126.       NULL, cb_data);
  127.   cb (".reg2", MIPSNBSD_NUM_FPREGS * regsize, &mipsnbsd_fpregset,
  128.       NULL, cb_data);
  129. }


  132. /* Conveniently, GDB uses the same register numbering as the
  133.    ptrace register structure used by NetBSD/mips.  */

  135. void
  136. ‌mipsnbsd_supply_reg (struct regcache *regcache, const char *regs, int regno)
  137. {
  138.   struct gdbarch *gdbarch = get_regcache_arch (regcache);
  139.   int i;

  141.   for (i = 0; i <= gdbarch_pc_regnum (gdbarch); i++)
  142.     {
  143.       if (regno == i || regno == -1)
  144.         {
  145.           if (gdbarch_cannot_fetch_register (gdbarch, i))
  146.             regcache_raw_supply (regcache, i, NULL);
  147.           else
  148.             regcache_raw_supply (regcache, i,
  149.                                  regs + (i * mips_isa_regsize (gdbarch)));
  150.         }
  151.     }
  152. }

  154. void
  155. ‌mipsnbsd_fill_reg (const struct regcache *regcache, char *regs, int regno)
  156. {
  157.   struct gdbarch *gdbarch = get_regcache_arch (regcache);
  158.   int i;

  160.   for (i = 0; i <= gdbarch_pc_regnum (gdbarch); i++)
  161.     if ((regno == i || regno == -1)
  162.         && ! gdbarch_cannot_store_register (gdbarch, i))
  163.       regcache_raw_collect (regcache, i,
  164.                             regs + (i * mips_isa_regsize (gdbarch)));
  165. }

  167. void
  168. ‌mipsnbsd_supply_fpreg (struct regcache *regcache,
  169.                        const char *fpregs, int regno)
  170. {
  171.   struct gdbarch *gdbarch = get_regcache_arch (regcache);
  172.   int i;

  174.   for (i = gdbarch_fp0_regnum (gdbarch);
  175.        i <= mips_regnum (gdbarch)->fp_implementation_revision;
  176.        i++)
  177.     {
  178.       if (regno == i || regno == -1)
  179.         {
  180.           if (gdbarch_cannot_fetch_register (gdbarch, i))
  181.             regcache_raw_supply (regcache, i, NULL);
  182.           else
  183.             regcache_raw_supply (regcache, i,
  184.                                  fpregs
  185.                                  + ((i - gdbarch_fp0_regnum (gdbarch))
  186.                                     * mips_isa_regsize (gdbarch)));
  187.         }
  188.     }
  189. }

  191. void
  192. ‌mipsnbsd_fill_fpreg (const struct regcache *regcache, char *fpregs, int regno)
  193. {
  194.   struct gdbarch *gdbarch = get_regcache_arch (regcache);
  195.   int i;

  197.   for (i = gdbarch_fp0_regnum (gdbarch);
  198.        i <= mips_regnum (gdbarch)->fp_control_status;
  199.        i++)
  200.     if ((regno == i || regno == -1)
  201.         && ! gdbarch_cannot_store_register (gdbarch, i))
  202.       regcache_raw_collect (regcache, i,
  203.                             fpregs + ((i - gdbarch_fp0_regnum (gdbarch))
  204.                               * mips_isa_regsize (gdbarch)));
  205. }

  207. #if 0

  209. /* Under NetBSD/mips, signal handler invocations can be identified by the
  210.    designated code sequence that is used to return from a signal handler.
  211.    In particular, the return address of a signal handler points to the
  212.    following code sequence:

  214.         addu        a0, sp, 16
  215.         li        v0, 295                        # __sigreturn14
  216.         syscall

  218.    Each instruction has a unique encoding, so we simply attempt to match
  219.    the instruction the PC is pointing to with any of the above instructions.
  220.    If there is a hit, we know the offset to the start of the designated
  221.    sequence and can then check whether we really are executing in the
  222.    signal trampoline.  If not, -1 is returned, otherwise the offset from the
  223.    start of the return sequence is returned.  */

  225. #define RETCODE_NWORDS        3
  226. #define RETCODE_SIZE        (RETCODE_NWORDS * 4)

  228. static const unsigned char sigtramp_retcode_mipsel[RETCODE_SIZE] =
  229. {
  230.   0x10, 0x00, 0xa4, 0x27,        /* addu a0, sp, 16 */
  231.   0x27, 0x01, 0x02, 0x24,        /* li v0, 295 */
  232.   0x0c, 0x00, 0x00, 0x00,        /* syscall */
  233. };

  235. static const unsigned char sigtramp_retcode_mipseb[RETCODE_SIZE] =
  236. {
  237.   0x27, 0xa4, 0x00, 0x10,        /* addu a0, sp, 16 */
  238.   0x24, 0x02, 0x01, 0x27,        /* li v0, 295 */
  239.   0x00, 0x00, 0x00, 0x0c,        /* syscall */
  240. };

  242. #endif

  244. /* Figure out where the longjmp will land.  We expect that we have
  245.    just entered longjmp and haven't yet setup the stack frame, so the
  246.    args are still in the argument regs.  MIPS_A0_REGNUM points at the
  247.    jmp_buf structure from which we extract the PC that we will land
  248.    at.  The PC is copied into *pc.  This routine returns true on
  249.    success.  */

  251. ‌#define NBSD_MIPS_JB_PC                        (2 * 4)
  252. ‌#define NBSD_MIPS_JB_ELEMENT_SIZE(gdbarch)        mips_isa_regsize (gdbarch)
  253. ‌#define NBSD_MIPS_JB_OFFSET(gdbarch)                (NBSD_MIPS_JB_PC * \
  254.                                          NBSD_MIPS_JB_ELEMENT_SIZE (gdbarch))

  256. static int
  257. ‌mipsnbsd_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
  258. {
  259.   struct gdbarch *gdbarch = get_frame_arch (frame);
  260.   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  261.   CORE_ADDR jb_addr;
  262.   gdb_byte *buf;

  264.   buf = alloca (NBSD_MIPS_JB_ELEMENT_SIZE (gdbarch));

  266.   jb_addr = get_frame_register_unsigned (frame, MIPS_A0_REGNUM);

  268.   if (target_read_memory (jb_addr + NBSD_MIPS_JB_OFFSET (gdbarch), buf,
  269.                             NBSD_MIPS_JB_ELEMENT_SIZE (gdbarch)))
  270.     return 0;

  272.   *pc = extract_unsigned_integer (buf, NBSD_MIPS_JB_ELEMENT_SIZE (gdbarch),
  273.                                   byte_order);
  274.   return 1;
  275. }

  277. static int
  278. ‌mipsnbsd_cannot_fetch_register (struct gdbarch *gdbarch, int regno)
  279. {
  280.   return (regno == MIPS_ZERO_REGNUM
  281.           || regno == mips_regnum (gdbarch)->fp_implementation_revision);
  282. }

  284. static int
  285. ‌mipsnbsd_cannot_store_register (struct gdbarch *gdbarch, int regno)
  286. {
  287.   return (regno == MIPS_ZERO_REGNUM
  288.           || regno == mips_regnum (gdbarch)->fp_implementation_revision);
  289. }

  291. /* Shared library support.  */

  293. /* NetBSD/mips uses a slightly different `struct link_map' than the
  294.    other NetBSD platforms.  */

  296. static struct link_map_offsets *
  297. ‌mipsnbsd_ilp32_fetch_link_map_offsets (void)
  298. {
  299.   static struct link_map_offsets lmo;
  300.   static struct link_map_offsets *lmp = NULL;

  302.   if (lmp == NULL)
  303.     {
  304.       lmp = &lmo;

  306.       lmo.r_version_offset = 0;
  307.       lmo.r_version_size = 4;
  308.       lmo.r_map_offset = 4;
  309.       lmo.r_brk_offset = 8;
  310.       lmo.r_ldsomap_offset = -1;

  312.       /* Everything we need is in the first 24 bytes.  */
  313.       lmo.link_map_size = 24;
  314.       lmo.l_addr_offset = 4;
  315.       lmo.l_name_offset = 8;
  316.       lmo.l_ld_offset = 12;
  317.       lmo.l_next_offset = 16;
  318.       lmo.l_prev_offset = 20;
  319.     }

  321.   return lmp;
  322. }

  324. static struct link_map_offsets *
  325. ‌mipsnbsd_lp64_fetch_link_map_offsets (void)
  326. {
  327.   static struct link_map_offsets lmo;
  328.   static struct link_map_offsets *lmp = NULL;

  330.   if (lmp == NULL)
  331.     {
  332.       lmp = &lmo;

  334.       lmo.r_version_offset = 0;
  335.       lmo.r_version_size = 4;
  336.       lmo.r_map_offset = 8;
  337.       lmo.r_brk_offset = 16;
  338.       lmo.r_ldsomap_offset = -1;

  340.       /* Everything we need is in the first 40 bytes.  */
  341.       lmo.link_map_size = 48;
  342.       lmo.l_addr_offset = 0;
  343.       lmo.l_name_offset = 16;
  344.       lmo.l_ld_offset = 24;
  345.       lmo.l_next_offset = 32;
  346.       lmo.l_prev_offset = 40;
  347.     }

  349.   return lmp;
  350. }


  353. static void
  354. ‌mipsnbsd_init_abi (struct gdbarch_info info,
  355.                    struct gdbarch *gdbarch)
  356. {
  357.   set_gdbarch_iterate_over_regset_sections
  358.     (gdbarch, mipsnbsd_iterate_over_regset_sections);

  360.   set_gdbarch_get_longjmp_target (gdbarch, mipsnbsd_get_longjmp_target);

  362.   set_gdbarch_cannot_fetch_register (gdbarch, mipsnbsd_cannot_fetch_register);
  363.   set_gdbarch_cannot_store_register (gdbarch, mipsnbsd_cannot_store_register);

  365.   set_gdbarch_software_single_step (gdbarch, mips_software_single_step);

  367.   /* NetBSD/mips has SVR4-style shared libraries.  */
  368.   set_solib_svr4_fetch_link_map_offsets
  369.     (gdbarch, (gdbarch_ptr_bit (gdbarch) == 32 ?
  370.                mipsnbsd_ilp32_fetch_link_map_offsets :
  371.                mipsnbsd_lp64_fetch_link_map_offsets));
  372. }


  375. /* Provide a prototype to silence -Wmissing-prototypes.  */
  376. extern initialize_file_ftype _initialize_mipsnbsd_tdep;

  378. void
  379. ‌_initialize_mipsnbsd_tdep (void)
  380. {
  381.   gdbarch_register_osabi (bfd_arch_mips, 0, GDB_OSABI_NETBSD_ELF,
  382.                           mipsnbsd_init_abi);
  383. }