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Handle MIPS Linux SIGTRAP siginfo.si_code values

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This unbreaks pending/delayed breakpoints handling, as well as
hardware watchpoints, on MIPS.

Ref: https://sourceware.org/ml/gdb-patches/2016-02/msg00681.html

The MIPS kernel reports SI_KERNEL for all kernel generated traps,
instead of TRAP_BRKPT / TRAP_HWBKPT, but GDB isn't aware of this.

Basically, this commit:

- Folds watchpoints logic into check_stopped_by_breakpoint, and
  renames it to save_stop_reason.

- Adds GDB_ARCH_IS_TRAP_HWBKPT.

- Makes MIPS set both GDB_ARCH_IS_TRAP_BRPT and
  GDB_ARCH_IS_TRAP_HWBKPT to SI_KERNEL.  In save_stop_reason, we
  handle the case of the same si_code returning true for both
  TRAP_BRPT and TRAP_HWBKPT by looking at what the debug registers
  say.

Tested on x86-64 Fedora 20, native and gdbserver.

gdb/ChangeLog:
2016-02-24  Pedro Alves  <palves@redhat.com>

	* linux-nat.c (save_sigtrap) Delete.
	(stop_wait_callback): Call save_stop_reason instead of
	save_sigtrap.
	(check_stopped_by_breakpoint): Rename to ...
	(save_stop_reason): ... this.  Bits of save_sigtrap folded here.
	Use GDB_ARCH_IS_TRAP_HWBKPT and handle ambiguous
	GDB_ARCH_IS_TRAP_BRKPT / GDB_ARCH_IS_TRAP_HWBKPT.  Factor out
	common code between the USE_SIGTRAP_SIGINFO and
	!USE_SIGTRAP_SIGINFO blocks.
	(linux_nat_filter_event): Call save_stop_reason instead of
	save_sigtrap.
	* nat/linux-ptrace.h: Check for both SI_KERNEL and TRAP_BRKPT
	si_code for MIPS.
	* nat/linux-ptrace.h: Fix "TRAP_HWBPT" typo in x86 table.  Add
	comments on MIPS behavior.
	(GDB_ARCH_IS_TRAP_HWBKPT): Define for all archs.

gdb/gdbserver/ChangeLog:
2016-02-24  Pedro Alves  <palves@redhat.com>

	* linux-low.c (check_stopped_by_breakpoint): Rename to ...
	(save_stop_reason): ... this.  Use GDB_ARCH_IS_TRAP_HWBKPT and
	handle ambiguous GDB_ARCH_IS_TRAP_BRKPT / GDB_ARCH_IS_TRAP_HWBKPT.
	Factor out common code between the USE_SIGTRAP_SIGINFO and
	!USE_SIGTRAP_SIGINFO blocks.
	(linux_low_filter_event): Call save_stop_reason instead of
	check_stopped_by_breakpoint and check_stopped_by_watchpoint.
	Update comments.
	(linux_wait_1): Update comments.
This commit is contained in:
Pedro Alves 2016-02-24 22:52:06 +00:00
parent 338435ef10
commit e7ad2f145c
5 changed files with 206 additions and 188 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
gdb/ChangeLog
View File

@ -1,3 +1,22 @@
2016-02-24 Pedro Alves <palves@redhat.com>
* linux-nat.c (save_sigtrap) Delete.
(stop_wait_callback): Call save_stop_reason instead of
save_sigtrap.
(check_stopped_by_breakpoint): Rename to ...
(save_stop_reason): ... this. Bits of save_sigtrap folded here.
Use GDB_ARCH_IS_TRAP_HWBKPT and handle ambiguous
GDB_ARCH_IS_TRAP_BRKPT / GDB_ARCH_IS_TRAP_HWBKPT. Factor out
common code between the USE_SIGTRAP_SIGINFO and
!USE_SIGTRAP_SIGINFO blocks.
(linux_nat_filter_event): Call save_stop_reason instead of
save_sigtrap.
* nat/linux-ptrace.h: Check for both SI_KERNEL and TRAP_BRKPT
si_code for MIPS.
* nat/linux-ptrace.h: Fix "TRAP_HWBPT" typo in x86 table. Add
comments on MIPS behavior.
(GDB_ARCH_IS_TRAP_HWBKPT): Define for all archs.
2016-02-24 Marcin Kościelnicki <koriakin@0x04.net>
* rs6000-tdep.c (rs6000_frame_cache): Initialize frame and pc to 0

12
gdb/gdbserver/ChangeLog
View File

@ -1,3 +1,15 @@
2016-02-24 Pedro Alves <palves@redhat.com>
* linux-low.c (check_stopped_by_breakpoint): Rename to ...
(save_stop_reason): ... this. Use GDB_ARCH_IS_TRAP_HWBKPT and
handle ambiguous GDB_ARCH_IS_TRAP_BRKPT / GDB_ARCH_IS_TRAP_HWBKPT.
Factor out common code between the USE_SIGTRAP_SIGINFO and
!USE_SIGTRAP_SIGINFO blocks.
(linux_low_filter_event): Call save_stop_reason instead of
check_stopped_by_breakpoint and check_stopped_by_watchpoint.
Update comments.
(linux_wait_1): Update comments.
2016-02-24 Wei-cheng Wang <cole945@gmail.com>
* linux-ppc-low.c (ppc_supports_z_point_type): New function:

174
gdb/gdbserver/linux-low.c
View File

@ -735,32 +735,16 @@ get_syscall_trapinfo (struct lwp_info *lwp, int *sysno, int *sysret)
current_thread = saved_thread;
}
/* This function should only be called if LWP got a SIGTRAP.
The SIGTRAP could mean several things.
static int check_stopped_by_watchpoint (struct lwp_info *child);
On i386, where decr_pc_after_break is non-zero:
If we were single-stepping this process using PTRACE_SINGLESTEP, we
will get only the one SIGTRAP. The value of $eip will be the next
instruction. If the instruction we stepped over was a breakpoint,
we need to decrement the PC.
If we continue the process using PTRACE_CONT, we will get a
SIGTRAP when we hit a breakpoint. The value of $eip will be
the instruction after the breakpoint (i.e. needs to be
decremented). If we report the SIGTRAP to GDB, we must also
report the undecremented PC. If the breakpoint is removed, we
must resume at the decremented PC.
On a non-decr_pc_after_break machine with hardware or kernel
single-step:
If we either single-step a breakpoint instruction, or continue and
hit a breakpoint instruction, our PC will point at the breakpoint
instruction. */
/* Called when the LWP stopped for a signal/trap. If it stopped for a
trap check what caused it (breakpoint, watchpoint, trace, etc.),
and save the result in the LWP's stop_reason field. If it stopped
for a breakpoint, decrement the PC if necessary on the lwp's
architecture. Returns true if we now have the LWP's stop PC. */
static int
check_stopped_by_breakpoint (struct lwp_info *lwp)
save_stop_reason (struct lwp_info *lwp)
{
CORE_ADDR pc;
CORE_ADDR sw_breakpoint_pc;
@ -785,56 +769,39 @@ check_stopped_by_breakpoint (struct lwp_info *lwp)
{
if (siginfo.si_signo == SIGTRAP)
{
if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code))
if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code)
&& GDB_ARCH_IS_TRAP_HWBKPT (siginfo.si_code))
{
if (debug_threads)
{
struct thread_info *thr = get_lwp_thread (lwp);
debug_printf ("CSBB: %s stopped by software breakpoint\n",
target_pid_to_str (ptid_of (thr)));
}
/* Back up the PC if necessary. */
if (pc != sw_breakpoint_pc)
{
struct regcache *regcache
= get_thread_regcache (current_thread, 1);
(*the_low_target.set_pc) (regcache, sw_breakpoint_pc);
}
lwp->stop_pc = sw_breakpoint_pc;
lwp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
current_thread = saved_thread;
return 1;
/* The si_code is ambiguous on this arch -- check debug
registers. */
if (!check_stopped_by_watchpoint (lwp))
lwp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
}
else if (siginfo.si_code == TRAP_HWBKPT)
else if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code))
{
if (debug_threads)
{
struct thread_info *thr = get_lwp_thread (lwp);
debug_printf ("CSBB: %s stopped by hardware "
"breakpoint/watchpoint\n",
target_pid_to_str (ptid_of (thr)));
}
lwp->stop_pc = pc;
lwp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
current_thread = saved_thread;
return 1;
/* If we determine the LWP stopped for a SW breakpoint,
trust it. Particularly don't check watchpoint
registers, because at least on s390, we'd find
stopped-by-watchpoint as long as there's a watchpoint
set. */
lwp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
}
else if (GDB_ARCH_IS_TRAP_HWBKPT (siginfo.si_code))
{
/* This can indicate either a hardware breakpoint or
hardware watchpoint. Check debug registers. */
if (!check_stopped_by_watchpoint (lwp))
lwp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
}
else if (siginfo.si_code == TRAP_TRACE)
{
if (debug_threads)
{
struct thread_info *thr = get_lwp_thread (lwp);
debug_printf ("CSBB: %s stopped by trace\n",
target_pid_to_str (ptid_of (thr)));
}
lwp->stop_reason = TARGET_STOPPED_BY_SINGLE_STEP;
/* We may have single stepped an instruction that
triggered a watchpoint. In that case, on some
architectures (such as x86), instead of TRAP_HWBKPT,
si_code indicates TRAP_TRACE, and we need to check
the debug registers separately. */
if (!check_stopped_by_watchpoint (lwp))
lwp->stop_reason = TARGET_STOPPED_BY_SINGLE_STEP;
}
}
}
@ -845,6 +812,16 @@ check_stopped_by_breakpoint (struct lwp_info *lwp)
case we need to report the breakpoint PC. */
if ((!lwp->stepping || lwp->stop_pc == sw_breakpoint_pc)
&& (*the_low_target.breakpoint_at) (sw_breakpoint_pc))
lwp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
if (hardware_breakpoint_inserted_here (pc))
lwp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
if (lwp->stop_reason == TARGET_STOPPED_BY_NO_REASON)
check_stopped_by_watchpoint (lwp);
#endif
if (lwp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT)
{
if (debug_threads)
{
@ -856,19 +833,16 @@ check_stopped_by_breakpoint (struct lwp_info *lwp)
/* Back up the PC if necessary. */
if (pc != sw_breakpoint_pc)
{
{
struct regcache *regcache
= get_thread_regcache (current_thread, 1);
(*the_low_target.set_pc) (regcache, sw_breakpoint_pc);
}
lwp->stop_pc = sw_breakpoint_pc;
lwp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
current_thread = saved_thread;
return 1;
/* Update this so we record the correct stop PC below. */
pc = sw_breakpoint_pc;
}
if (hardware_breakpoint_inserted_here (pc))
else if (lwp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
{
if (debug_threads)
{
@ -877,16 +851,31 @@ check_stopped_by_breakpoint (struct lwp_info *lwp)
debug_printf ("CSBB: %s stopped by hardware breakpoint\n",
target_pid_to_str (ptid_of (thr)));
}
lwp->stop_pc = pc;
lwp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
current_thread = saved_thread;
return 1;
}
#endif
else if (lwp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT)
{
if (debug_threads)
{
struct thread_info *thr = get_lwp_thread (lwp);
debug_printf ("CSBB: %s stopped by hardware watchpoint\n",
target_pid_to_str (ptid_of (thr)));
}
}
else if (lwp->stop_reason == TARGET_STOPPED_BY_SINGLE_STEP)
{
if (debug_threads)
{
struct thread_info *thr = get_lwp_thread (lwp);
debug_printf ("CSBB: %s stopped by trace\n",
target_pid_to_str (ptid_of (thr)));
}
}
lwp->stop_pc = pc;
current_thread = saved_thread;
return 0;
return 1;
}
static struct lwp_info *
@ -2434,8 +2423,8 @@ linux_low_filter_event (int lwpid, int wstat)
child->syscall_state = TARGET_WAITKIND_IGNORE;
}
/* Be careful to not overwrite stop_pc until
check_stopped_by_breakpoint is called. */
/* Be careful to not overwrite stop_pc until save_stop_reason is
called. */
if (WIFSTOPPED (wstat) && WSTOPSIG (wstat) == SIGTRAP
&& linux_is_extended_waitstatus (wstat))
{
@ -2448,27 +2437,12 @@ linux_low_filter_event (int lwpid, int wstat)
}
}
/* Check first whether this was a SW/HW breakpoint before checking
watchpoints, because at least s390 can't tell the data address of
hardware watchpoint hits, and returns stopped-by-watchpoint as
long as there's a watchpoint set. */
if (WIFSTOPPED (wstat) && linux_wstatus_maybe_breakpoint (wstat))
{
if (check_stopped_by_breakpoint (child))
if (save_stop_reason (child))
have_stop_pc = 1;
}
/* Note that TRAP_HWBKPT can indicate either a hardware breakpoint
or hardware watchpoint. Check which is which if we got
TARGET_STOPPED_BY_HW_BREAKPOINT. Likewise, we may have single
stepped an instruction that triggered a watchpoint. In that
case, on some architectures (such as x86), instead of
TRAP_HWBKPT, si_code indicates TRAP_TRACE, and we need to check
the debug registers separately. */
if (WIFSTOPPED (wstat) && WSTOPSIG (wstat) == SIGTRAP
&& child->stop_reason != TARGET_STOPPED_BY_SW_BREAKPOINT)
check_stopped_by_watchpoint (child);
if (!have_stop_pc)
child->stop_pc = get_pc (child);
@ -3209,7 +3183,7 @@ linux_wait_1 (ptid_t ptid,
hardware single step it means a gdb/gdbserver breakpoint had been
planted on top of a permanent breakpoint, in the case of a software
single step it may just mean that gdbserver hit the reinsert breakpoint.
The PC has been adjusted by check_stopped_by_breakpoint to point at
The PC has been adjusted by save_stop_reason to point at
the breakpoint address.
So in the case of the hardware single step advance the PC manually
past the breakpoint and in the case of software single step advance only

151
gdb/linux-nat.c
View File

@ -303,10 +303,11 @@ static struct lwp_info *find_lwp_pid (ptid_t ptid);
static int lwp_status_pending_p (struct lwp_info *lp);
static int check_stopped_by_breakpoint (struct lwp_info *lp);
static int sigtrap_is_event (int status);
static int (*linux_nat_status_is_event) (int status) = sigtrap_is_event;
static void save_stop_reason (struct lwp_info *lp);
/* LWP accessors. */
@ -2321,30 +2322,6 @@ check_stopped_by_watchpoint (struct lwp_info *lp)
return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
}
/* Called when the LWP stopped for a trap that could be explained by a
watchpoint or a breakpoint. */
static void
save_sigtrap (struct lwp_info *lp)
{
gdb_assert (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON);
gdb_assert (lp->status != 0);
/* Check first if this was a SW/HW breakpoint before checking
watchpoints, because at least s390 can't tell the data address of
hardware watchpoint hits, and the kernel returns
stopped-by-watchpoint as long as there's a watchpoint set. */
if (linux_nat_status_is_event (lp->status))
check_stopped_by_breakpoint (lp);
/* Note that TRAP_HWBKPT can indicate either a hardware breakpoint
or hardware watchpoint. Check which is which if we got
TARGET_STOPPED_BY_HW_BREAKPOINT. */
if (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON
|| lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
check_stopped_by_watchpoint (lp);
}
/* Returns true if the LWP had stopped for a watchpoint. */
static int
@ -2441,7 +2418,7 @@ stop_wait_callback (struct lwp_info *lp, void *data)
/* Save the sigtrap event. */
lp->status = status;
gdb_assert (lp->signalled);
save_sigtrap (lp);
save_stop_reason (lp);
}
else
{
@ -2583,29 +2560,32 @@ select_event_lwp_callback (struct lwp_info *lp, void *data)
return 0;
}
/* Called when the LWP got a signal/trap that could be explained by a
software or hardware breakpoint. */
/* Called when the LWP stopped for a signal/trap. If it stopped for a
trap check what caused it (breakpoint, watchpoint, trace, etc.),
and save the result in the LWP's stop_reason field. If it stopped
for a breakpoint, decrement the PC if necessary on the lwp's
architecture. */
static int
check_stopped_by_breakpoint (struct lwp_info *lp)
static void
save_stop_reason (struct lwp_info *lp)
{
/* Arrange for a breakpoint to be hit again later. We don't keep
the SIGTRAP status and don't forward the SIGTRAP signal to the
LWP. We will handle the current event, eventually we will resume
this LWP, and this breakpoint will trap again.
If we do not do this, then we run the risk that the user will
delete or disable the breakpoint, but the LWP will have already
tripped on it. */
struct regcache *regcache = get_thread_regcache (lp->ptid);
struct gdbarch *gdbarch = get_regcache_arch (regcache);
struct regcache *regcache;
struct gdbarch *gdbarch;
CORE_ADDR pc;
CORE_ADDR sw_bp_pc;
#if USE_SIGTRAP_SIGINFO
siginfo_t siginfo;
#endif
gdb_assert (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON);
gdb_assert (lp->status != 0);
if (!linux_nat_status_is_event (lp->status))
return;
regcache = get_thread_regcache (lp->ptid);
gdbarch = get_regcache_arch (regcache);
pc = regcache_read_pc (regcache);
sw_bp_pc = pc - gdbarch_decr_pc_after_break (gdbarch);
@ -2614,33 +2594,29 @@ check_stopped_by_breakpoint (struct lwp_info *lp)
{
if (siginfo.si_signo == SIGTRAP)
{
if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code))
if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code)
&& GDB_ARCH_IS_TRAP_HWBKPT (siginfo.si_code))
{
if (debug_linux_nat)
fprintf_unfiltered (gdb_stdlog,
"CSBB: %s stopped by software "
"breakpoint\n",
target_pid_to_str (lp->ptid));
/* Back up the PC if necessary. */
if (pc != sw_bp_pc)
regcache_write_pc (regcache, sw_bp_pc);
lp->stop_pc = sw_bp_pc;
lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
return 1;
/* The si_code is ambiguous on this arch -- check debug
registers. */
if (!check_stopped_by_watchpoint (lp))
lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
}
else if (siginfo.si_code == TRAP_HWBKPT)
else if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code))
{
if (debug_linux_nat)
fprintf_unfiltered (gdb_stdlog,
"CSBB: %s stopped by hardware "
"breakpoint/watchpoint\n",
target_pid_to_str (lp->ptid));
lp->stop_pc = pc;
lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
return 1;
/* If we determine the LWP stopped for a SW breakpoint,
trust it. Particularly don't check watchpoint
registers, because at least on s390, we'd find
stopped-by-watchpoint as long as there's a watchpoint
set. */
lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
}
else if (GDB_ARCH_IS_TRAP_HWBKPT (siginfo.si_code))
{
/* This can indicate either a hardware breakpoint or
hardware watchpoint. Check debug registers. */
if (!check_stopped_by_watchpoint (lp))
lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
}
else if (siginfo.si_code == TRAP_TRACE)
{
@ -2648,6 +2624,13 @@ check_stopped_by_breakpoint (struct lwp_info *lp)
fprintf_unfiltered (gdb_stdlog,
"CSBB: %s stopped by trace\n",
target_pid_to_str (lp->ptid));
/* We may have single stepped an instruction that
triggered a watchpoint. In that case, on some
architectures (such as x86), instead of TRAP_HWBKPT,
si_code indicates TRAP_TRACE, and we need to check
the debug registers separately. */
check_stopped_by_watchpoint (lp);
}
}
}
@ -2658,6 +2641,18 @@ check_stopped_by_breakpoint (struct lwp_info *lp)
{
/* The LWP was either continued, or stepped a software
breakpoint instruction. */
lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
}
if (hardware_breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
if (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON)
check_stopped_by_watchpoint (lp);
#endif
if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT)
{
if (debug_linux_nat)
fprintf_unfiltered (gdb_stdlog,
"CSBB: %s stopped by software breakpoint\n",
@ -2667,25 +2662,25 @@ check_stopped_by_breakpoint (struct lwp_info *lp)
if (pc != sw_bp_pc)
regcache_write_pc (regcache, sw_bp_pc);
lp->stop_pc = sw_bp_pc;
lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
return 1;
/* Update this so we record the correct stop PC below. */
pc = sw_bp_pc;
}
if (hardware_breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
else if (lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
{
if (debug_linux_nat)
fprintf_unfiltered (gdb_stdlog,
"CSBB: stopped by hardware breakpoint %s\n",
"CSBB: %s stopped by hardware breakpoint\n",
target_pid_to_str (lp->ptid));
}
else if (lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT)
{
if (debug_linux_nat)
fprintf_unfiltered (gdb_stdlog,
"CSBB: %s stopped by hardware watchpoint\n",
target_pid_to_str (lp->ptid));
lp->stop_pc = pc;
lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
return 1;
}
#endif
return 0;
lp->stop_pc = pc;
}
@ -3057,7 +3052,7 @@ linux_nat_filter_event (int lwpid, int status)
/* An interesting event. */
gdb_assert (lp);
lp->status = status;
save_sigtrap (lp);
save_stop_reason (lp);
return lp;
}

38
gdb/nat/linux-ptrace.h
View File

@ -119,14 +119,14 @@ struct buffer;
/* The x86 kernel gets some of the si_code values backwards, like
this:
| what | si_code |
|------------------------------------------+------------|
| software breakpoints (int3) | SI_KERNEL |
| single-steps | TRAP_TRACE |
| single-stepping a syscall | TRAP_BRKPT |
| user sent SIGTRAP | 0 |
| exec SIGTRAP (when no PTRACE_EVENT_EXEC) | 0 |
| hardware breakpoints/watchpoints | TRAP_HWBPT |
| what | si_code |
|------------------------------------------+-------------|
| software breakpoints (int3) | SI_KERNEL |
| single-steps | TRAP_TRACE |
| single-stepping a syscall | TRAP_BRKPT |
| user sent SIGTRAP | 0 |
| exec SIGTRAP (when no PTRACE_EVENT_EXEC) | 0 |
| hardware breakpoints/watchpoints | TRAP_HWBKPT |
That is, it reports SI_KERNEL for software breakpoints (and only
for those), and TRAP_BRKPT for single-stepping a syscall... If the
@ -140,14 +140,32 @@ struct buffer;
in SPU code on a Cell/B.E. However, SI_KERNEL is never seen
on a SIGTRAP for any other reason.
The generic Linux target code should use GDB_ARCH_IS_TRAP_BRKPT
instead of TRAP_BRKPT to abstract out these peculiarities. */
The MIPS kernel uses SI_KERNEL for all kernel generated traps.
Since:
- MIPS doesn't do hardware single-step.
- We don't need to care about exec SIGTRAPs --- we assume
PTRACE_EVENT_EXEC is available.
- The MIPS kernel doesn't support hardware breakpoints.
on MIPS, all we need to care about is distinguishing between
software breakpoints and hardware watchpoints, which can be done by
peeking the debug registers.
The generic Linux target code should use GDB_ARCH_IS_TRAP_* instead
of TRAP_* to abstract out these peculiarities. */
#if defined __i386__ || defined __x86_64__
# define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == SI_KERNEL)
# define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == TRAP_HWBKPT)
#elif defined __powerpc__
# define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == SI_KERNEL || (X) == TRAP_BRKPT)
# define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == TRAP_HWBKPT)
#elif defined __mips__
# define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == SI_KERNEL)
# define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == SI_KERNEL)
#else
# define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == TRAP_BRKPT)
# define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == TRAP_HWBKPT)
#endif
#ifndef TRAP_HWBKPT