250 lines
7.0 KiB
C
250 lines
7.0 KiB
C
/* Target-dependent code for GNU/Linux on Alpha.
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Copyright (C) 2002, 2003, 2007, 2008, 2009, 2010
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Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "frame.h"
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#include "gdb_assert.h"
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#include "gdb_string.h"
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#include "osabi.h"
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#include "solib-svr4.h"
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#include "symtab.h"
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#include "regset.h"
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#include "regcache.h"
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#include "alpha-tdep.h"
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/* Under GNU/Linux, signal handler invocations can be identified by
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the designated code sequence that is used to return from a signal
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handler. In particular, the return address of a signal handler
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points to a sequence that copies $sp to $16, loads $0 with the
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appropriate syscall number, and finally enters the kernel.
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This is somewhat complicated in that:
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(1) the expansion of the "mov" assembler macro has changed over
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time, from "bis src,src,dst" to "bis zero,src,dst",
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(2) the kernel has changed from using "addq" to "lda" to load the
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syscall number,
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(3) there is a "normal" sigreturn and an "rt" sigreturn which
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has a different stack layout.
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*/
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static long
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alpha_linux_sigtramp_offset_1 (struct gdbarch *gdbarch, CORE_ADDR pc)
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{
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switch (alpha_read_insn (gdbarch, pc))
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{
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case 0x47de0410: /* bis $30,$30,$16 */
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case 0x47fe0410: /* bis $31,$30,$16 */
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return 0;
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case 0x43ecf400: /* addq $31,103,$0 */
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case 0x201f0067: /* lda $0,103($31) */
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case 0x201f015f: /* lda $0,351($31) */
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return 4;
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case 0x00000083: /* call_pal callsys */
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return 8;
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default:
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return -1;
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}
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}
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static LONGEST
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alpha_linux_sigtramp_offset (struct gdbarch *gdbarch, CORE_ADDR pc)
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{
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long i, off;
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if (pc & 3)
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return -1;
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/* Guess where we might be in the sequence. */
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off = alpha_linux_sigtramp_offset_1 (gdbarch, pc);
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if (off < 0)
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return -1;
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/* Verify that the other two insns of the sequence are as we expect. */
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pc -= off;
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for (i = 0; i < 12; i += 4)
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{
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if (i == off)
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continue;
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if (alpha_linux_sigtramp_offset_1 (gdbarch, pc + i) != i)
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return -1;
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}
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return off;
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}
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static int
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alpha_linux_pc_in_sigtramp (struct gdbarch *gdbarch,
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CORE_ADDR pc, char *func_name)
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{
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return alpha_linux_sigtramp_offset (gdbarch, pc) >= 0;
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}
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static CORE_ADDR
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alpha_linux_sigcontext_addr (struct frame_info *this_frame)
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{
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struct gdbarch *gdbarch = get_frame_arch (this_frame);
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CORE_ADDR pc;
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ULONGEST sp;
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long off;
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pc = get_frame_pc (this_frame);
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sp = get_frame_register_unsigned (this_frame, ALPHA_SP_REGNUM);
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off = alpha_linux_sigtramp_offset (gdbarch, pc);
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gdb_assert (off >= 0);
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/* __NR_rt_sigreturn has a couple of structures on the stack. This is:
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struct rt_sigframe {
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struct siginfo info;
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struct ucontext uc;
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};
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offsetof (struct rt_sigframe, uc.uc_mcontext);
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*/
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if (alpha_read_insn (gdbarch, pc - off + 4) == 0x201f015f)
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return sp + 176;
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/* __NR_sigreturn has the sigcontext structure at the top of the stack. */
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return sp;
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}
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/* Supply register REGNUM from the buffer specified by GREGS and LEN
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in the general-purpose register set REGSET to register cache
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REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */
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static void
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alpha_linux_supply_gregset (const struct regset *regset,
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struct regcache *regcache,
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int regnum, const void *gregs, size_t len)
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{
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const gdb_byte *regs = gregs;
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int i;
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gdb_assert (len >= 32 * 8);
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for (i = 0; i < ALPHA_ZERO_REGNUM; i++)
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{
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if (regnum == i || regnum == -1)
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regcache_raw_supply (regcache, i, regs + i * 8);
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}
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if (regnum == ALPHA_PC_REGNUM || regnum == -1)
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regcache_raw_supply (regcache, ALPHA_PC_REGNUM, regs + 31 * 8);
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if (regnum == ALPHA_UNIQUE_REGNUM || regnum == -1)
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regcache_raw_supply (regcache, ALPHA_UNIQUE_REGNUM,
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len >= 33 * 8 ? regs + 32 * 8 : NULL);
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}
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/* Supply register REGNUM from the buffer specified by FPREGS and LEN
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in the floating-point register set REGSET to register cache
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REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */
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static void
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alpha_linux_supply_fpregset (const struct regset *regset,
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struct regcache *regcache,
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int regnum, const void *fpregs, size_t len)
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{
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const gdb_byte *regs = fpregs;
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int i;
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gdb_assert (len >= 32 * 8);
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for (i = ALPHA_FP0_REGNUM; i < ALPHA_FP0_REGNUM + 31; i++)
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{
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if (regnum == i || regnum == -1)
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regcache_raw_supply (regcache, i, regs + (i - ALPHA_FP0_REGNUM) * 8);
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}
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if (regnum == ALPHA_FPCR_REGNUM || regnum == -1)
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regcache_raw_supply (regcache, ALPHA_FPCR_REGNUM, regs + 31 * 8);
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}
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static struct regset alpha_linux_gregset =
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{
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NULL,
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alpha_linux_supply_gregset
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};
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static struct regset alpha_linux_fpregset =
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{
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NULL,
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alpha_linux_supply_fpregset
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};
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/* Return the appropriate register set for the core section identified
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by SECT_NAME and SECT_SIZE. */
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static const struct regset *
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alpha_linux_regset_from_core_section (struct gdbarch *gdbarch,
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const char *sect_name, size_t sect_size)
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{
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if (strcmp (sect_name, ".reg") == 0 && sect_size >= 32 * 8)
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return &alpha_linux_gregset;
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if (strcmp (sect_name, ".reg2") == 0 && sect_size >= 32 * 8)
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return &alpha_linux_fpregset;
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return NULL;
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}
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static void
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alpha_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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{
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struct gdbarch_tdep *tdep;
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/* Hook into the DWARF CFI frame unwinder. */
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alpha_dwarf2_init_abi (info, gdbarch);
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/* Hook into the MDEBUG frame unwinder. */
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alpha_mdebug_init_abi (info, gdbarch);
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tdep = gdbarch_tdep (gdbarch);
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tdep->dynamic_sigtramp_offset = alpha_linux_sigtramp_offset;
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tdep->sigcontext_addr = alpha_linux_sigcontext_addr;
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tdep->pc_in_sigtramp = alpha_linux_pc_in_sigtramp;
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tdep->jb_pc = 2;
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tdep->jb_elt_size = 8;
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set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
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set_solib_svr4_fetch_link_map_offsets
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(gdbarch, svr4_lp64_fetch_link_map_offsets);
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/* Enable TLS support. */
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set_gdbarch_fetch_tls_load_module_address (gdbarch,
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svr4_fetch_objfile_link_map);
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set_gdbarch_regset_from_core_section
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(gdbarch, alpha_linux_regset_from_core_section);
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}
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/* Provide a prototype to silence -Wmissing-prototypes. */
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extern initialize_file_ftype _initialize_alpha_linux_tdep;
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void
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_initialize_alpha_linux_tdep (void)
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{
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gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_LINUX,
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alpha_linux_init_abi);
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}
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