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/* GNU/Linux on TI C6x target support.
Copyright (C) 2011-2021 Free Software Foundation, Inc.
Contributed by Yao Qi <yao@codesourcery.com>
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "solib.h"
#include "osabi.h"
#include "linux-tdep.h"
#include "tic6x-tdep.h"
#include "trad-frame.h"
#include "tramp-frame.h"
#include "elf-bfd.h"
#include "elf/tic6x.h"
#include "gdbarch.h"
/* The offset from rt_sigframe pointer to SP register. */
#define TIC6X_SP_RT_SIGFRAME 8
/* Size of struct siginfo info. */
#define TIC6X_SIGINFO_SIZE 128
/* Size of type stack_t, which contains three fields of type void*, int, and
size_t respectively. */
#define TIC6X_STACK_T_SIZE (3 * 4)
static const gdb_byte tic6x_bkpt_bnop_be[] = { 0x00, 0x00, 0xa1, 0x22 };
static const gdb_byte tic6x_bkpt_bnop_le[] = { 0x22, 0xa1, 0x00, 0x00 };
/* Return the offset of register REGNUM in struct sigcontext. Return 0 if no
such register in sigcontext. */
static unsigned int
tic6x_register_sigcontext_offset (unsigned int regnum, struct gdbarch *gdbarch)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
if (regnum == TIC6X_A4_REGNUM || regnum == TIC6X_A4_REGNUM + 2
|| regnum == TIC6X_A4_REGNUM + 4)
return 4 * (regnum - TIC6X_A4_REGNUM + 2); /* A4, A6, A8 */
else if (regnum == TIC6X_A5_REGNUM || regnum == TIC6X_A5_REGNUM + 2
|| regnum == TIC6X_A5_REGNUM + 4)
return 4 * (regnum - TIC6X_A5_REGNUM + 12); /* A5, A7, A9 */
else if (regnum == TIC6X_B4_REGNUM || regnum == TIC6X_B4_REGNUM + 2
|| regnum == TIC6X_B4_REGNUM + 4)
return 4 * (regnum - TIC6X_B4_REGNUM + 3); /* B4, B6, B8 */
else if (regnum == TIC6X_B5_REGNUM || regnum == TIC6X_B5_REGNUM + 2
|| regnum == TIC6X_B5_REGNUM + 4)
return 4 * (regnum - TIC6X_B5_REGNUM + 19); /* B5, B7, B9 */
else if (regnum < TIC6X_A4_REGNUM)
return 4 * (regnum - 0 + 8); /* A0 - A3 */
else if (regnum >= TIC6X_B0_REGNUM && regnum < TIC6X_B4_REGNUM)
return 4 * (regnum - TIC6X_B0_REGNUM + 15); /* B0 - B3 */
else if (regnum >= 34 && regnum < 34 + 32)
return 4 * (regnum - 34 + 23); /* A16 - A31, B16 - B31 */
else if (regnum == TIC6X_PC_REGNUM)
return 4 * (tdep->has_gp ? 55 : 23);
else if (regnum == TIC6X_SP_REGNUM)
return 4;
return 0;
}
/* Support unwinding frame in signal trampoline. We don't check sigreturn,
since it is not used in kernel. */
static void
tic6x_linux_rt_sigreturn_init (const struct tramp_frame *self,
struct frame_info *this_frame,
struct trad_frame_cache *this_cache,
CORE_ADDR func)
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
CORE_ADDR sp = get_frame_register_unsigned (this_frame, TIC6X_SP_REGNUM);
/* The base of struct sigcontext is computed by examining the definition of
struct rt_sigframe in linux kernel source arch/c6x/kernel/signal.c. */
CORE_ADDR base = (sp + TIC6X_SP_RT_SIGFRAME
/* Pointer type *pinfo and *puc in struct rt_sigframe. */
+ 4 + 4
+ TIC6X_SIGINFO_SIZE
+ 4 + 4 /* uc_flags and *uc_link in struct ucontext. */
+ TIC6X_STACK_T_SIZE);
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
unsigned int reg_offset;
unsigned int i;
for (i = 0; i < 10; i++) /* A0 - A9 */
{
reg_offset = tic6x_register_sigcontext_offset (i, gdbarch);
gdb_assert (reg_offset != 0);
trad_frame_set_reg_addr (this_cache, i, base + reg_offset);
}
for (i = TIC6X_B0_REGNUM; i < TIC6X_B0_REGNUM + 10; i++) /* B0 - B9 */
{
reg_offset = tic6x_register_sigcontext_offset (i, gdbarch);
gdb_assert (reg_offset != 0);
trad_frame_set_reg_addr (this_cache, i, base + reg_offset);
}
if (tdep->has_gp)
for (i = 34; i < 34 + 32; i++) /* A16 - A31, B16 - B31 */
{
reg_offset = tic6x_register_sigcontext_offset (i, gdbarch);
gdb_assert (reg_offset != 0);
trad_frame_set_reg_addr (this_cache, i, base + reg_offset);
}
trad_frame_set_reg_addr (this_cache, TIC6X_PC_REGNUM,
base + tic6x_register_sigcontext_offset (TIC6X_PC_REGNUM,
gdbarch));
trad_frame_set_reg_addr (this_cache, TIC6X_SP_REGNUM,
base + tic6x_register_sigcontext_offset (TIC6X_SP_REGNUM,
gdbarch));
/* Save a frame ID. */
trad_frame_set_id (this_cache, frame_id_build (sp, func));
}
static struct tramp_frame tic6x_linux_rt_sigreturn_tramp_frame =
{
SIGTRAMP_FRAME,
4,
{
{0x000045aa, 0x0fffffff}, /* mvk .S2 139,b0 */
{0x10000000, ULONGEST_MAX}, /* swe */
{TRAMP_SENTINEL_INSN}
},
tic6x_linux_rt_sigreturn_init
};
/* When FRAME is at a syscall instruction, return the PC of the next
instruction to be executed. */
static CORE_ADDR
tic6x_linux_syscall_next_pc (struct frame_info *frame)
{
ULONGEST syscall_number = get_frame_register_unsigned (frame,
TIC6X_B0_REGNUM);
CORE_ADDR pc = get_frame_pc (frame);
if (syscall_number == 139 /* rt_sigreturn */)
return frame_unwind_caller_pc (frame);
return pc + 4;
}
extern struct target_so_ops dsbt_so_ops;
static void
tic6x_uclinux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
linux_init_abi (info, gdbarch, 0);
/* Shared library handling. */
set_solib_ops (gdbarch, &dsbt_so_ops);
tdep->syscall_next_pc = tic6x_linux_syscall_next_pc;
#ifdef HAVE_ELF
/* In tic6x Linux kernel, breakpoint instructions varies on different archs.
On C64x+ and C67x+, breakpoint instruction is 0x56454314, which is an
illegal opcode. On other arch, breakpoint instruction is 0x0000a122
(BNOP .S2 0,5). */
if (info.abfd)
switch (bfd_elf_get_obj_attr_int (info.abfd, OBJ_ATTR_PROC, Tag_ISA))
{
case C6XABI_Tag_ISA_C64XP:
case C6XABI_Tag_ISA_C67XP:
if (info.byte_order == BFD_ENDIAN_BIG)
tdep->breakpoint = tic6x_bkpt_illegal_opcode_be;
else
tdep->breakpoint = tic6x_bkpt_illegal_opcode_le;
break;
default:
{
if (info.byte_order == BFD_ENDIAN_BIG)
tdep->breakpoint = tic6x_bkpt_bnop_be;
else
tdep->breakpoint = tic6x_bkpt_bnop_le;
}
}
#endif
/* Signal trampoline support. */
tramp_frame_prepend_unwinder (gdbarch,
&tic6x_linux_rt_sigreturn_tramp_frame);
}
void _initialize_tic6x_linux_tdep ();
void
_initialize_tic6x_linux_tdep ()
{
gdbarch_register_osabi (bfd_arch_tic6x, 0, GDB_OSABI_LINUX,
tic6x_uclinux_init_abi);
}
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