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/* Target-dependent code for GNU/Linux SPARC.
Copyright 2003, 2004 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 2 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, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include "defs.h"
#include "floatformat.h"
#include "frame.h"
#include "frame-unwind.h"
#include "tramp-frame.h"
#include "gdbarch.h"
#include "gdbcore.h"
#include "osabi.h"
#include "regcache.h"
#include "solib-svr4.h"
#include "symtab.h"
#include "trad-frame.h"
#include "sparc-tdep.h"
/* Signal trampoline support. */
/* GNU/Linux has two flavors of signals. Normal signal handlers, and
"realtime" (RT) signals. The RT signals can provide additional
information to the signal handler if the SA_SIGINFO flag is set
when establishing a signal handler using `sigaction'. It is not
unlikely that future versions of GNU/Linux will support SA_SIGINFO
for normal signals too. */
/* When the sparc Linux kernel calls a signal handler and the
SA_RESTORER flag isn't set, the return address points to a bit of
code on the stack. This function returns whether the PC appears to
be within this bit of code.
The instruction sequence for normal signals is
mov __NR_sigreturn, %g1 ! hex: 0x821020d8
ta 0x10 ! hex: 0x91d02010
Checking for the code sequence should be somewhat reliable, because
the effect is to call the system call sigreturn. This is unlikely
to occur anywhere other than a signal trampoline.
It kind of sucks that we have to read memory from the process in
order to identify a signal trampoline, but there doesn't seem to be
any other way. However, sparc32_linux_pc_in_sigtramp arranges to
only call us if no function name could be identified, which should
be the case since the code is on the stack. */
#define LINUX32_SIGTRAMP_INSN0 0x821020d8 /* mov __NR_sigreturn, %g1 */
#define LINUX32_SIGTRAMP_INSN1 0x91d02010 /* ta 0x10 */
/* The instruction sequence for RT signals is
mov __NR_rt_sigreturn, %g1 ! hex: 0x82102065
ta {0x10,0x6d} ! hex: 0x91d02010
The effect is to call the system call rt_sigreturn.
Note that 64-bit binaries only use this RT signal return method. */
#define LINUX32_RT_SIGTRAMP_INSN0 0x82102065
#define LINUX32_RT_SIGTRAMP_INSN1 0x91d02010
static void sparc32_linux_sigframe_init (const struct tramp_frame *self,
struct frame_info *next_frame,
struct trad_frame_cache *this_cache,
CORE_ADDR func);
static const struct tramp_frame sparc32_linux_sigframe = {
SIGTRAMP_FRAME,
4,
{
{ LINUX32_SIGTRAMP_INSN0, -1 },
{ LINUX32_SIGTRAMP_INSN1, -1 },
{ TRAMP_SENTINEL_INSN, -1 }
},
sparc32_linux_sigframe_init
};
static const struct tramp_frame sparc32_linux_rt_sigframe = {
SIGTRAMP_FRAME,
4,
{
{ LINUX32_RT_SIGTRAMP_INSN0, -1 },
{ LINUX32_RT_SIGTRAMP_INSN1, -1 },
{ TRAMP_SENTINEL_INSN, -1 }
},
sparc32_linux_sigframe_init
};
static void
sparc32_linux_sigframe_init (const struct tramp_frame *self,
struct frame_info *next_frame,
struct trad_frame_cache *this_cache,
CORE_ADDR func)
{
CORE_ADDR base, addr;
int regnum;
base = frame_unwind_register_unsigned (next_frame, SPARC_O1_REGNUM);
if (self == &sparc32_linux_rt_sigframe)
base += 128;
/* Offsets from <bits/sigcontext.h> */
trad_frame_set_reg_addr (this_cache, SPARC32_PSR_REGNUM, base + 0x00);
trad_frame_set_reg_addr (this_cache, SPARC32_PC_REGNUM, base + 0x04);
trad_frame_set_reg_addr (this_cache, SPARC32_NPC_REGNUM, base + 0x08);
trad_frame_set_reg_addr (this_cache, SPARC32_Y_REGNUM, base + 0x0c);
/* Since %g0 is always zero, keep the identity encoding. */
addr = base + 0x14;
for (regnum = SPARC_G1_REGNUM; regnum <= SPARC_O7_REGNUM; regnum++)
{
trad_frame_set_reg_addr (this_cache, regnum, addr);
addr += 4;
}
base = addr = frame_unwind_register_unsigned (next_frame, SPARC_SP_REGNUM);
for (regnum = SPARC_L0_REGNUM; regnum <= SPARC_I7_REGNUM; regnum++)
{
trad_frame_set_reg_addr (this_cache, regnum, addr);
addr += 4;
}
trad_frame_set_id (this_cache, frame_id_build (base, func));
}
static void
sparc32_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
tramp_frame_prepend_unwinder (gdbarch, &sparc32_linux_sigframe);
tramp_frame_prepend_unwinder (gdbarch, &sparc32_linux_rt_sigframe);
/* GNU/Linux is very similar to Solaris ... */
sparc32_sol2_init_abi (info, gdbarch);
/* ... but doesn't have kernel-assisted single-stepping support. */
set_gdbarch_software_single_step (gdbarch, sparc_software_single_step);
/* GNU/Linux doesn't support the 128-bit `long double' from the psABI. */
set_gdbarch_long_double_bit (gdbarch, 64);
set_gdbarch_long_double_format (gdbarch, &floatformat_ieee_double_big);
/* Enable TLS support. */
set_gdbarch_fetch_tls_load_module_address (gdbarch,
svr4_fetch_objfile_link_map);
}
/* Provide a prototype to silence -Wmissing-prototypes. */
extern void _initialize_sparc_linux_tdep (void);
void
_initialize_sparc_linux_tdep (void)
{
gdbarch_register_osabi (bfd_arch_sparc, 0, GDB_OSABI_LINUX,
sparc32_linux_init_abi);
}
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