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/* Target-dependent code for FreeBSD on RISC-V processors.
Copyright (C) 2018-2023 Free Software Foundation, Inc.
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 "fbsd-tdep.h"
#include "osabi.h"
#include "riscv-tdep.h"
#include "riscv-fbsd-tdep.h"
#include "solib-svr4.h"
#include "target.h"
#include "trad-frame.h"
#include "tramp-frame.h"
#include "gdbarch.h"
#include "inferior.h"
/* Register maps. */
static const struct regcache_map_entry riscv_fbsd_gregmap[] =
{
{ 1, RISCV_RA_REGNUM, 0 },
{ 1, RISCV_SP_REGNUM, 0 },
{ 1, RISCV_GP_REGNUM, 0 },
{ 1, RISCV_TP_REGNUM, 0 },
{ 3, 5, 0 }, /* t0 - t2 */
{ 4, 28, 0 }, /* t3 - t6 */
{ 2, RISCV_FP_REGNUM, 0 }, /* s0 - s1 */
{ 10, 18, 0 }, /* s2 - s11 */
{ 8, RISCV_A0_REGNUM, 0 }, /* a0 - a7 */
{ 1, RISCV_PC_REGNUM, 0 },
{ 1, RISCV_CSR_SSTATUS_REGNUM, 0 },
{ 0 }
};
static const struct regcache_map_entry riscv_fbsd_fpregmap[] =
{
{ 32, RISCV_FIRST_FP_REGNUM, 16 },
{ 1, RISCV_CSR_FCSR_REGNUM, 8 },
{ 0 }
};
/* Register set definitions. */
const struct regset riscv_fbsd_gregset =
{
riscv_fbsd_gregmap, riscv_supply_regset, regcache_collect_regset
};
const struct regset riscv_fbsd_fpregset =
{
riscv_fbsd_fpregmap, riscv_supply_regset, regcache_collect_regset
};
/* Implement the "iterate_over_regset_sections" gdbarch method. */
static void
riscv_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
iterate_over_regset_sections_cb *cb,
void *cb_data,
const struct regcache *regcache)
{
cb (".reg", RISCV_FBSD_NUM_GREGS * riscv_isa_xlen (gdbarch),
RISCV_FBSD_NUM_GREGS * riscv_isa_xlen (gdbarch),
&riscv_fbsd_gregset, NULL, cb_data);
cb (".reg2", RISCV_FBSD_SIZEOF_FPREGSET, RISCV_FBSD_SIZEOF_FPREGSET,
&riscv_fbsd_fpregset, NULL, cb_data);
}
/* In a signal frame, sp points to a 'struct sigframe' which is
defined as:
struct sigframe {
siginfo_t sf_si;
ucontext_t sf_uc;
};
ucontext_t is defined as:
struct __ucontext {
sigset_t uc_sigmask;
mcontext_t uc_mcontext;
...
};
The mcontext_t contains the general purpose register set followed
by the floating point register set. The floating point register
set is only valid if the _MC_FP_VALID flag is set in mc_flags. */
#define RISCV_SIGFRAME_UCONTEXT_OFFSET 80
#define RISCV_UCONTEXT_MCONTEXT_OFFSET 16
#define RISCV_MCONTEXT_FLAG_FP_VALID 0x1
/* Implement the "init" method of struct tramp_frame. */
static void
riscv_fbsd_sigframe_init (const struct tramp_frame *self,
frame_info_ptr this_frame,
struct trad_frame_cache *this_cache,
CORE_ADDR func)
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
CORE_ADDR sp = get_frame_register_unsigned (this_frame, RISCV_SP_REGNUM);
CORE_ADDR mcontext_addr
= (sp
+ RISCV_SIGFRAME_UCONTEXT_OFFSET
+ RISCV_UCONTEXT_MCONTEXT_OFFSET);
gdb_byte buf[4];
trad_frame_set_reg_regmap (this_cache, riscv_fbsd_gregmap, mcontext_addr,
RISCV_FBSD_NUM_GREGS * riscv_isa_xlen (gdbarch));
CORE_ADDR fpregs_addr
= mcontext_addr + RISCV_FBSD_NUM_GREGS * riscv_isa_xlen (gdbarch);
CORE_ADDR fp_flags_addr
= fpregs_addr + RISCV_FBSD_SIZEOF_FPREGSET;
if (target_read_memory (fp_flags_addr, buf, 4) == 0
&& (extract_unsigned_integer (buf, 4, byte_order)
& RISCV_MCONTEXT_FLAG_FP_VALID))
trad_frame_set_reg_regmap (this_cache, riscv_fbsd_fpregmap, fpregs_addr,
RISCV_FBSD_SIZEOF_FPREGSET);
trad_frame_set_id (this_cache, frame_id_build (sp, func));
}
/* RISC-V supports 16-bit instructions ("C") as well as 32-bit
instructions. The signal trampoline on FreeBSD uses a mix of
these, but tramp_frame assumes a fixed instruction size. To cope,
claim that all instructions are 16 bits and use two "slots" for
32-bit instructions. */
static const struct tramp_frame riscv_fbsd_sigframe =
{
SIGTRAMP_FRAME,
2,
{
{0x850a, ULONGEST_MAX}, /* mov a0, sp */
{0x0513, ULONGEST_MAX}, /* addi a0, a0, #SF_UC */
{0x0505, ULONGEST_MAX},
{0x0293, ULONGEST_MAX}, /* li t0, #SYS_sigreturn */
{0x1a10, ULONGEST_MAX},
{0x0073, ULONGEST_MAX}, /* ecall */
{0x0000, ULONGEST_MAX},
{TRAMP_SENTINEL_INSN, ULONGEST_MAX}
},
riscv_fbsd_sigframe_init
};
/* Implement the "get_thread_local_address" gdbarch method. */
static CORE_ADDR
riscv_fbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid,
CORE_ADDR lm_addr, CORE_ADDR offset)
{
struct regcache *regcache;
regcache = get_thread_arch_regcache (current_inferior ()->process_target (),
ptid, gdbarch);
target_fetch_registers (regcache, RISCV_TP_REGNUM);
ULONGEST tp;
if (regcache->cooked_read (RISCV_TP_REGNUM, &tp) != REG_VALID)
error (_("Unable to fetch %%tp"));
/* %tp points to the end of the TCB which contains two pointers.
The first pointer in the TCB points to the DTV array. */
CORE_ADDR dtv_addr = tp - (gdbarch_ptr_bit (gdbarch) / 8) * 2;
return fbsd_get_thread_local_address (gdbarch, dtv_addr, lm_addr, offset);
}
/* Implement the 'init_osabi' method of struct gdb_osabi_handler. */
static void
riscv_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
/* Generic FreeBSD support. */
fbsd_init_abi (info, gdbarch);
set_gdbarch_software_single_step (gdbarch, riscv_software_single_step);
set_solib_svr4_fetch_link_map_offsets (gdbarch,
(riscv_isa_xlen (gdbarch) == 4
? svr4_ilp32_fetch_link_map_offsets
: svr4_lp64_fetch_link_map_offsets));
tramp_frame_prepend_unwinder (gdbarch, &riscv_fbsd_sigframe);
set_gdbarch_iterate_over_regset_sections
(gdbarch, riscv_fbsd_iterate_over_regset_sections);
set_gdbarch_fetch_tls_load_module_address (gdbarch,
svr4_fetch_objfile_link_map);
set_gdbarch_get_thread_local_address (gdbarch,
riscv_fbsd_get_thread_local_address);
}
void _initialize_riscv_fbsd_tdep ();
void
_initialize_riscv_fbsd_tdep ()
{
gdbarch_register_osabi (bfd_arch_riscv, 0, GDB_OSABI_FREEBSD,
riscv_fbsd_init_abi);
}
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