This patch adds some sanity check that reinsert breakpoints must be
there when doing step-over on software single step target. The check
triggers an assert when running forking-threads-plus-breakpoint.exp
on arm-linux target,
gdb/gdbserver/linux-low.c:4714: A problem internal to GDBserver has been detected.^M
int finish_step_over(lwp_info*): Assertion `has_reinsert_breakpoints ()' failed.
the error happens when GDBserver has already resumed a thread of
process A for step-over (and wait for it hitting reinsert breakpoint),
but receives detach request for process B from GDB, which is shown in
the backtrace below,
(gdb) bt
#2 0x000228aa in finish_step_over (lwp=0x12bbd98) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:4703
#3 0x00025a50 in finish_step_over (lwp=0x12bbd98) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:4749
#4 complete_ongoing_step_over () at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:4760
#5 linux_detach (pid=25228) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:1503
#6 0x00012bae in process_serial_event () at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/server.c:3974
#7 handle_serial_event (err=<optimized out>, client_data=<optimized out>) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/server.c:4347
#8 0x00016d68 in handle_file_event (event_file_desc=<optimized out>) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/event-loop.c:429
#9 0x000173ea in process_event () at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/event-loop.c:184
#10 start_event_loop () at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/event-loop.c:547
#11 0x0000aa2c in captured_main (argv=<optimized out>, argc=<optimized out>) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/server.c:3719
#12 main (argc=<optimized out>, argv=<optimized out>) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/server.c:3804
the sanity check tries to find the reinsert breakpoint from process B,
but nothing is found. It is wrong, we need to search in process A,
since we started step-over of a thread of process A.
(gdb) p lwp->thread->entry.id
$3 = {pid = 25120, lwp = 25131, tid = 0}
(gdb) p current_thread->entry.id
$4 = {pid = 25228, lwp = 25228, tid = 0}
This patch switched current_thread to the thread we are doing step-over
in finish_step_over.
gdb/gdbserver:
2016-06-17 Yao Qi <yao.qi@linaro.org>
* linux-low.c (maybe_hw_step): New function.
(linux_resume_one_lwp_throw): Call maybe_hw_step.
(finish_step_over): Switch current_thread to lwp temporarily,
and assert has_reinsert_breakpoints returns true.
(proceed_one_lwp): Call maybe_hw_step.
* mem-break.c (has_reinsert_breakpoints): New function.
* mem-break.h (has_reinsert_breakpoints): Declare.
This patch is to replace find_inferior (&all_threads, unsuspend_one_lwp, NULL)
with unsuspend_all_lwps (NULL), which is shorter. They are equivalent
to each other.
gdb/gdbserver:
2016-05-17 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_stabilize_threads): Call unsuspend_all_lwps
instead of find_inferior.
Hi,
I happen to see that field need_step_over in struct lwp_info is only
used to print a debug info. need_step_over is set in linux_wait_1
when breakpoint_here is true, however, we check breakpoint_here too in
need_step_over_p and do the step over. I think we don't need field
need_step_over, and check breakpoint_here directly in need_step_over_p.
This field was added in this patch
https://sourceware.org/ml/gdb-patches/2010-03/msg00605.html and the code
wasn't changed much since then.
This patch is to remove it.
gdb/gdbserver:
2016-04-28 Yao Qi <yao.qi@linaro.org>
* linux-low.h (struct lwp_info) <need_step_over>: Remove.
* linux-low.c (linux_wait_1): Update.
(need_step_over_p): Likewise.
When GDBserver steps over a breakpoint using software single step, it
enqueues the signal, single step and deliver the signal in the next
resume if step over is not needed. In this way, the program won't
receive the signal if the conditional breakpoint is set a branch to
self instruction, because the step over is always needed.
This patch removes the restriction that don't deliver the signal to
the inferior if we are trying to reinsert a breakpoint for software
single step and change the decision on resume vs. step-over when the
LWP has pending signals to deliver.
gdb/gdbserver:
2016-04-25 Yao Qi <yao.qi@linaro.org>
* linux-low.c (lwp_signal_can_be_delivered): Adjust.
(need_step_over_p): Return zero if the LWP has pending signals
can be delivered on software single step target.
GDBserver doesn't deliver signal when stepping over a breakpoint even
hardware single step is used. When GDBserver started to step over
(thread creation) breakpoint for mutlit-threaded debugging in 2002 [1],
GDBserver behaves this way.
This behavior gets trouble on conditional breakpoints on branch to
self instruction like this,
0x00000000004005b6 <+29>: jmp 0x4005b6 <main+29>
and I set breakpoint
$(gdb) break branch-to-self.c:43 if counter > 3
and the variable counter will be set to 5 in SIGALRM signal handler.
Since GDBserver keeps stepping over breakpoint, the SIGALRM can never
be dequeued and delivered to the inferior, so the program can't stop.
The test can be found in gdb.base/branch-to-self.exp.
GDBserver didn't deliver signal when stepping over a breakpoint because
a tracepoint is collected twice if GDBserver does so in the following
scenario, which can be reproduced by gdb.trace/signal.exp.
- program stops at tracepoint, and tracepoint is collected,
- gdbserver starts a step-over,
- a signal arrives, step-over is canceled, and signal should be passed,
- gdbserver starts a new step-over again, pass the signal as well,
- program stops at the entry of signal handler, step-over finished,
- gdbserver proceeds,
- program returns from the signal handler, again to the tracepoint,
and thus is collected again.
The spurious collection isn't that harmful, IMO, so it should be OK
to let GDBserver deliver signal when stepping over a breakpoint.
gdb/gdbserver:
2016-04-22 Yao Qi <yao.qi@linaro.org>
* linux-low.c (lwp_signal_can_be_delivered): Don't deliver
signal when stepping over breakpoint with software single
step.
gdb/testsuite:
2016-04-22 Yao Qi <yao.qi@linaro.org>
* gdb.trace/signal.exp: Also pass if
$tracepoint_hits($i) > $iterations.
The enqueue and dequeue signals in linux_resume_one_lwp_throw use one
condition and its inverted one. This patch is to move the condition
into a function lwp_signal_can_be_delivered, so that the next patch can
change the condition in one place.
gdb/gdbserver:
2016-03-18 Yao Qi <yao.qi@linaro.org>
* linux-low.c (lwp_signal_can_be_delivered): New function.
(linux_resume_one_lwp_throw): Use lwp_signal_can_be_delivered.
Today, we enqueue signal in linux_resume_one_lwp_throw, but set
variable 'signal' many lines below with the comment
/* Postpone any pending signal. It was enqueued above. */
signal = 0;
I feel difficult to associate code across many lines, and we should
move the code close to enqueue_pending_signal call. This is what
this patch does in general. After this change, variable 'signal'
is set to zero very early, so the 'signal' value in the following
debugging message makes no sense, so I remove it from the debugging
message. The function returns early if lwp->status_pending_p is
true, so 'signal' value in the debugging message doesn't matter,
AFAICS. Also, I move one debugging message several lines below to
make it close the real ptrace call,
if (debug_threads)
debug_printf ("Resuming lwp %ld (%s, signal %d, stop %s)\n",
lwpid_of (thread), step ? "step" : "continue", signal,
lwp->stop_expected ? "expected" : "not expected");
so that the debugging message can reflect what GDBserver does. This
is a code refactor and only debugging messages are affected.
gdb/gdbserver:
2016-03-18 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_resume_one_lwp_throw): Set 'signal' to
0 if signal is enqueued. Remove 'signal' from one debugging
message. Move one debugging message to some lines below.
Remove code setting 'signal' to 0.
WIFSTOPPED is checked linux_wstatus_maybe_breakpoint, so WIFSTOPPED
in "WIFSTOPPED (wstat) && linux_wstatus_maybe_breakpoint (wstat)"
is redundant. This patch removes WIFSTOPPED check.
gdb/gdbserver:
2016-03-18 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_low_filter_event): Remove redundant
WIFSTOPPED check together with linux_wstatus_maybe_breakpoint.
I happen to see that comments to start_step_over isn't in sync with
code, so this patch is to update the comments.
gdb/gdbserver:
2016-03-03 Yao Qi <yao.qi@linaro.org>
* linux-low.c: Update comments to start_step_over.
I see the following GDBserver internal error in two cases,
gdb/gdbserver/linux-low.c:1922: A problem internal to GDBserver has been detected.
unsuspend LWP 17200, suspended=-1
1. step over a breakpoint on fork/vfork syscall instruction,
2. step over a breakpoint on clone syscall instruction and child
threads hits a breakpoint,
the stack backtrace is
#0 internal_error (file=file@entry=0x44c4c0 "gdb/gdbserver/linux-low.c", line=line@entry=1922,
fmt=fmt@entry=0x44c7d0 "unsuspend LWP %ld, suspended=%d\n") at gdb/gdbserver/../common/errors.c:51
#1 0x0000000000424014 in lwp_suspended_decr (lwp=<optimised out>, lwp=<optimised out>) at gdb/gdbserver/linux-low.c:1922
#2 0x000000000042403a in unsuspend_one_lwp (entry=<optimised out>, except=0x66e8c0) at gdb/gdbserver/linux-low.c:2885
#3 0x0000000000405f45 in find_inferior (list=<optimised out>, func=func@entry=0x424020 <unsuspend_one_lwp>, arg=arg@entry=0x66e8c0)
at gdb/gdbserver/inferiors.c:243
#4 0x00000000004297de in unsuspend_all_lwps (except=0x66e8c0) at gdb/gdbserver/linux-low.c:2895
#5 linux_wait_1 (ptid=..., ourstatus=ourstatus@entry=0x665ec0 <last_status>, target_options=target_options@entry=0)
at gdb/gdbserver/linux-low.c:3632
#6 0x000000000042a764 in linux_wait (ptid=..., ourstatus=0x665ec0 <last_status>, target_options=0)
at gdb/gdbserver/linux-low.c:3770
#7 0x0000000000411163 in mywait (ptid=..., ourstatus=ourstatus@entry=0x665ec0 <last_status>, options=options@entry=0, connected_wait=connected_wait@entry=1)
at gdb/gdbserver/target.c:214
#8 0x000000000040b1f2 in resume (actions=0x66f800, num_actions=1) at gdb/gdbserver/server.c:2757
#9 0x000000000040f660 in handle_v_cont (own_buf=0x66a630 "vCont;c:p45e9.-1") at gdb/gdbserver/server.c:2719
when GDBserver steps over a thread, other threads have been suspended,
the "stepping" thread may create new thread, but GDBserver doesn't set
it suspend count to 1. When GDBserver unsuspend threads, the child's
suspend count goes to -1, and the assert is triggered. In fact, GDBserver
has already taken care of suspend count of new thread when GDBserver is
suspending all threads except the one GDBserver wants to step over by
https://sourceware.org/ml/gdb-patches/2015-07/msg00946.html
+ /* If we're suspending all threads, leave this one suspended
+ too. */
+ if (stopping_threads == STOPPING_AND_SUSPENDING_THREADS)
+ {
+ if (debug_threads)
+ debug_printf ("HEW: leaving child suspended\n");
+ child_lwp->suspended = 1;
+ }
but that is not enough, because new thread is still can be spawned in
the thread which is being stepped over. This patch extends the
condition that GDBserver set child's suspend count to one if it is
suspending threads or stepping over the thread.
gdb/gdbserver:
2016-03-03 Yao Qi <yao.qi@linaro.org>
PR server/19736
* linux-low.c (handle_extended_wait): Set child suspended
if event_lwp->bp_reinsert isn't zero.
Replace the code which is exactly what enqueue_pending_signal does.
gdb/gdbserver:
2016-03-02 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_resume_one_lwp_throw): Replace code with
enqueue_pending_signal.
If gdbserver and IPA are using different tdesc, they will disagree
about 'R' trace packet size. This results in mangled traces.
To make sure they pick the same tdesc, gdbserver pokes the tdesc
(specified as an index in a target-specific list) into a global
variable in IPA. In theory, IPA could find out the tdesc on its
own, but that may be complex (in particular, I don't know how to
tell whether we have LAST_BREAK on s390 without messing with ptrace),
and we'd have to duplicate the logic.
Tested on i386 and x86_64. On i386, it fixes two FAILs in ftrace.exp.
On x86_64, these failures have been KFAILed - one of them works now,
but the other now fails due to an unrelated reason (ugh).
gdb/gdbserver/ChangeLog:
PR gdb/13808
* Makefile.in: Add i386-*-linux-ipa.o and amd64-*-linux-ipa.o.
* configure.srv: Ditto.
* linux-aarch64-ipa.c (get_ipa_tdesc): New function.
(initialize_low_tracepoint): Remove ipa_tdesc assignment.
* linux-amd64-ipa.c: Add "linux-x86-tdesc.h" include.
(init_registers_amd64_linux): Remove prototype.
(tdesc_amd64_linux): Remove declaration.
(get_ipa_tdesc): New function.
(initialize_low_tracepoint): Remove ipa_tdesc assignment,
initialize remaining tdescs.
* linux-i386-ipa.c: Add "linux-x86-tdesc.h" include.
(init_registers_i386_linux): Remove prototype.
(tdesc_i386_linux): Remove declaration.
(get_ipa_tdesc): New function.
(initialize_low_tracepoint): Remove ipa_tdesc assignment,
initialize remaining tdescs.
* linux-low.c (linux_get_ipa_tdesc_idx): New function.
(linux_target_ops): wire in linux_get_ipa_tdesc_idx.
* linux-low.h (struct linux_target_ops): Add get_ipa_tdesc_idx.
* linux-x86-low.c: Move tdesc declarations to linux-x86-tdesc.h.
(x86_get_ipa_tdesc_idx): New function.
(the_low_target): Wire in x86_get_ipa_tdesc_idx.
* linux-x86-tdesc.h: New file.
* target.h (struct target_ops): Add get_ipa_tdesc_idx.
(target_get_ipa_tdesc_idx): New macro.
* tracepoint.c (ipa_tdesc_idx): New macro.
(struct ipa_sym_addresses): Add addr_ipa_tdesc_idx.
(symbol_list): Add ipa_tdesc_idx.
(cmd_qtstart): Write ipa_tdesc_idx in the target.
(ipa_tdesc): Remove.
(ipa_tdesc_idx): New variable.
(get_context_regcache): Use get_ipa_tdesc.
(gdb_collect): Ditto.
(gdb_probe): Ditto.
* tracepoint.h (get_ipa_tdesc): New prototype.
(ipa_tdesc): Remove.
gdb/testsuite/ChangeLog:
PR gdb/13808
* gdb.trace/ftrace.exp (test_fast_tracepoints): Remove kfail.
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.
Change the signature of gdbserver's siginfo_fixup functions so that it's
in line with gdb's. This gets rid of the following build error in C++:
/home/emaisin/src/binutils-gdb/gdb/gdbserver/linux-x86-low.c: In function ‘int x86_siginfo_fixup(siginfo_t*, void*, int)’:
/home/emaisin/src/binutils-gdb/gdb/gdbserver/linux-x86-low.c:694:21: error: invalid conversion from ‘void*’ to ‘gdb_byte* {aka unsigned char*}’ [-fpermissive]
FIXUP_32);
^
In file included from /home/emaisin/src/binutils-gdb/gdb/gdbserver/linux-x86-low.c:31:0:
/home/emaisin/src/binutils-gdb/gdb/gdbserver/../nat/amd64-linux-siginfo.h:52:5: error: initializing argument 2 of ‘int amd64_linux_siginfo_fixup_common(siginfo_t*, gdb_byte*, int, amd64_siginfo_fixup_mode)’ [-fpermissive]
int amd64_linux_siginfo_fixup_common (siginfo_t *native, gdb_byte *inf,
^
/home/emaisin/src/binutils-gdb/gdb/gdbserver/linux-x86-low.c:698:20: error: invalid conversion from ‘void*’ to ‘gdb_byte* {aka unsigned char*}’ [-fpermissive]
FIXUP_X32);
^
In file included from /home/emaisin/src/binutils-gdb/gdb/gdbserver/linux-x86-low.c:31:0:
/home/emaisin/src/binutils-gdb/gdb/gdbserver/../nat/amd64-linux-siginfo.h:52:5: error: initializing argument 2 of ‘int amd64_linux_siginfo_fixup_common(siginfo_t*, gdb_byte*, int, amd64_siginfo_fixup_mode)’ [-fpermissive]
int amd64_linux_siginfo_fixup_common (siginfo_t *native, gdb_byte *inf,
^
gdb/gdbserver/ChangeLog:
* linux-aarch64-low.c (aarch64_linux_siginfo_fixup): Change
void * to gdb_byte *.
* linux-low.c (siginfo_fixup): Likewise.
(linux_xfer_siginfo): Likewise.
* linux-low.h (struct linux_target_ops) <siginfo_fixup>:
Likewise.
* linux-x86-low.c (x86_siginfo_fixup): Likewise.
Nowadays, get_next_pcs in linux_target_ops has two parameters PC
and REGCACHE. Parameter PC looks redundant because it can be go
from REGCACHE. The patch is to remove PC from the arguments for
various functions.
gdb:
2016-01-26 Yao Qi <yao.qi@linaro.org>
* arch/arm-get-next-pcs.c (thumb_deal_with_atomic_sequence_raw):
Remove argument pc. Get pc by regcache_read_pc. Callers updated.
(arm_deal_with_atomic_sequence_raw): Likewise.
(thumb_get_next_pcs_raw): Likewise.
(arm_get_next_pcs_raw): Likewise.
(arm_get_next_pcs): Remove argument pc. Callers updated.
* arch/arm-get-next-pcs.h (arm_get_next_pcs): Update declaration.
gdb/gdbserver:
2016-01-26 Yao Qi <yao.qi@linaro.org>
* linux-arm-low.c (arm_gdbserver_get_next_pcs): Remove argument pc.
* linux-low.c (install_software_single_step_breakpoints): Don't
call regcache_read_pc.
* linux-low.h (struct linux_target_ops) <get_next_pcs>: Remove
argument pc.
In install_software_single_step_breakpoints, we've got the regcache
of current_thread, so we don't have to bother get_pc to get pc,
instead we can get pc from regcache directly. Note that the callers
of install_software_single_step_breakpoints have already switched
current_thread to LWP.
Since the pc is got from regcache_read_pc, in the next patch, we can
get pc inside the implementation of *the_low_target.get_next_pcs and
stop passing pc to *the_low_target.get_next_pcs.
gdb/gdbserver:
2016-01-26 Yao Qi <yao.qi@linaro.org>
* linux-low.c (install_software_single_step_breakpoints): Call
regcache_read_pc instead of get_pc.
This patch is the follow-up of
https://sourceware.org/ml/gdb-patches/2016-01/msg00164.html to provide
linux_{get,set}_pc_64bit functions.
Rebuild GDBserver with tilegx-linux-gcc. Not tested.
I think about pc in Tile-GX a little bit. Looks current Tile-GX
supports debugging 32-bit program (multi-arch), but PC is always
64-bit. See this thread
https://sourceware.org/ml/gdb-patches/2013-02/msg00113.html
and GDBserver reads PC as 64-bit through ptrace. However, if
the inferior is 32-bit, the PC in the target description and
regcache is 32-bit, so only 32-bit contents are sent back GDB.
Anyway, Tile-GX GDBserver may have some problems here, but this
patch doesn't change anything.
gdb/gdbserver:
2016-01-18 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_set_pc_64bit): New function.
(linux_get_pc_64bit): New function.
* linux-low.h (linux_set_pc_64bit, linux_get_pc_64bit):
Declare.
* linux-sparc-low.c (debug_threads): Remove declaration.
(sparc_get_pc): Remove.
(the_low_target): Use linux_get_pc_64bit instead of
sparc_get_pc.
* linux-tile-low.c (tile_get_pc, tile_set_pc): Remove.
(the_low_target): Use linux_get_pc_64bit and
linux_set_pc_64bit.
This patch adds a pair of new functions linux_get_pc_32bit and
linux_set_pc_32bit which get and set 32-bit register "pc" from
regcache. This function can be used some targets and these own
$ARCH_{get,set}_pc are replaced by linux_{get,set}_pc_32bit
respectively.
This patch touches many targets, but I only have arm board to
test and no regression. I also rebuilt nios2-linux GDBserver.
If it is right to go, I'll post the 64-bit counterpart later.
gdb/gdbserver:
2016-01-18 Yao Qi <yao.qi@linaro.org>
* linux-arm-low.c (debug_threads): Remove declaration.
(arm_get_pc, arm_set_pc): Remove.
(the_low_target): Use linux_get_pc_32bit and
linux_set_pc_32bit.
* linux-bfin-low.c (bfin_get_pc, bfin_set_pc): Remove.
(the_low_target): Use linux_get_pc_32bit and
linux_set_pc_32bit.
* linux-cris-low.c (debug_threads): Remove declaration.
(cris_get_pc, cris_set_pc,): Remove.
(the_low_target): Use linux_get_pc_32bit and
linux_set_pc_32bit.
* linux-crisv32-low.c (debug_threads): Remove declaration.
(cris_get_pc, cris_set_pc): Remove.
(the_low_target): Use linux_get_pc_32bit and
linux_set_pc_32bit.
* linux-low.c: Include inttypes.h.
(linux_get_pc_32bit, linux_set_pc_32bit): New functions.
* linux-low.h (linux_get_pc_32bit, linux_set_pc_32bit): Declare.
* linux-m32r-low.c (m32r_get_pc, m32r_set_pc): Remove.
(the_low_target): Use linux_get_pc_32bit and
linux_set_pc_32bit.
* linux-m68k-low.c (m68k_get_pc, m68k_set_pc): Remove.
(the_low_target): Use linux_get_pc_32bit and
linux_set_pc_32bit.
* linux-nios2-low.c (nios2_get_pc, nios2_set_pc): Remove.
(the_low_target): Use linux_get_pc_32bit and
linux_set_pc_32bit.
* linux-sh-low.c (sh_get_pc, sh_set_pc): Remove.
(the_low_target): Use linux_get_pc_32bit and
linux_set_pc_32bit.
* linux-xtensa-low.c (xtensa_get_pc, xtensa_set_pc): Remove.
(the_low_target): Use linux_get_pc_32bit and
linux_set_pc_32bit.
This adds a new QCatchSyscalls packet to enable 'catch syscall', and new
stop reasons "syscall_entry" and "syscall_return" for those events. It
is currently only supported on Linux x86 and x86_64.
gdb/ChangeLog:
2016-01-12 Josh Stone <jistone@redhat.com>
Philippe Waroquiers <philippe.waroquiers@skynet.be>
* NEWS (Changes since GDB 7.10): Mention QCatchSyscalls and the
syscall_entry and syscall_return stop reasons. Mention GDB
support for remote catch syscall.
* remote.c (PACKET_QCatchSyscalls): New enum.
(remote_set_syscall_catchpoint): New function.
(remote_protocol_features): New element for QCatchSyscalls.
(remote_parse_stop_reply): Parse syscall_entry/return stops.
(init_remote_ops): Install remote_set_syscall_catchpoint.
(_initialize_remote): Config QCatchSyscalls.
* linux-nat.h (struct lwp_info) <syscall_state>: Comment typo.
gdb/doc/ChangeLog:
2016-01-12 Josh Stone <jistone@redhat.com>
Philippe Waroquiers <philippe.waroquiers@skynet.be>
* gdb.texinfo (Remote Configuration): List the QCatchSyscalls packet.
(Stop Reply Packets): List the syscall entry and return stop reasons.
(General Query Packets): Describe QCatchSyscalls, and add it to the
table and the detailed list of stub features.
gdb/gdbserver/ChangeLog:
2016-01-12 Josh Stone <jistone@redhat.com>
Philippe Waroquiers <philippe.waroquiers@skynet.be>
* inferiors.h: Include "gdb_vecs.h".
(struct process_info): Add syscalls_to_catch.
* inferiors.c (remove_process): Free syscalls_to_catch.
* remote-utils.c (prepare_resume_reply): Report syscall_entry and
syscall_return stops.
* server.h (UNKNOWN_SYSCALL, ANY_SYSCALL): Define.
* server.c (handle_general_set): Handle QCatchSyscalls.
(handle_query): Report support for QCatchSyscalls.
* target.h (struct target_ops): Add supports_catch_syscall.
(target_supports_catch_syscall): New macro.
* linux-low.h (struct linux_target_ops): Add get_syscall_trapinfo.
(struct lwp_info): Add syscall_state.
* linux-low.c (handle_extended_wait): Mark syscall_state as an entry.
Maintain syscall_state and syscalls_to_catch across exec.
(get_syscall_trapinfo): New function, proxy to the_low_target.
(linux_low_ptrace_options): Enable PTRACE_O_TRACESYSGOOD.
(linux_low_filter_event): Toggle syscall_state entry/return for
syscall traps, and set it ignored for all others.
(gdb_catching_syscalls_p): New function.
(gdb_catch_this_syscall_p): New function.
(linux_wait_1): Handle SYSCALL_SIGTRAP.
(linux_resume_one_lwp_throw): Add PTRACE_SYSCALL possibility.
(linux_supports_catch_syscall): New function.
(linux_target_ops): Install it.
* linux-x86-low.c (x86_get_syscall_trapinfo): New function.
(the_low_target): Install it.
gdb/testsuite/ChangeLog:
2016-01-12 Josh Stone <jistone@redhat.com>
Philippe Waroquiers <philippe.waroquiers@skynet.be>
* gdb.base/catch-syscall.c (do_execve): New variable.
(main): Conditionally trigger an execve.
* gdb.base/catch-syscall.exp: Enable testing for remote targets.
(test_catch_syscall_execve): New, check entry/return across execve.
(do_syscall_tests): Call test_catch_syscall_execve.
The GNU Coding Standards say:
"Please do not include any trademark acknowledgements in GNU
software packages or documentation."
gdb/ChangeLog:
2016-01-12 Pedro Alves <palves@redhat.com>
Remove use of the registered trademark symbol throughout.
gdb/gdbserver/ChangeLog:
2016-01-12 Pedro Alves <palves@redhat.com>
Remove use of the registered trademark symbol throughout.
gdb/doc/ChangeLog:
2016-01-12 Pedro Alves <palves@redhat.com>
Remove use of the registered trademark symbol throughout.
This patch enables software single stepping if the targets support it,
to do while-stepping actions.
No regressions, tested on ubuntu 14.04 ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
gdb/gdbserver/ChangeLog:
* linux-low.c (single_step): New function.
(linux_resume_one_lwp_throw): Call single_step.
(start_step_over): Likewise.
This patch in preparation for software single step support on ARM. It refactors
breakpoint_reinsert_addr into get_next_pcs so that multiple location can be
returned.
When software single stepping there can be multiple possible next addresses
because we're stepping over a conditional branch instruction, for example.
The operation get_next_pcs handles that by returning a vector of all the
possible next addresses.
Software breakpoints are installed at each location returned.
No regressions, tested on ubuntu 14.04 ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
gdb/gdbserver/ChangeLog:
* linux-aarch64-low.c (the_low_targets): Rename
breakpoint_reinsert_addr to get_next_pcs.
* linux-arm-low.c (the_low_targets): Likewise.
* linux-bfin-low.c (the_low_targets): Likewise.
* linux-cris-low.c (the_low_targets): Likewise.
* linux-crisv32-low.c (the_low_targets): Likewise.
* linux-low.c (can_software_single_step): Likewise.
(install_software_single_step_breakpoints): New function.
(start_step_over): Use install_software_single_step_breakpoints.
* linux-low.h: New CORE_ADDR vector.
(struct linux_target_ops) Rename breakpoint_reinsert_addr to
get_next_pcs.
* linux-mips-low.c (the_low_targets): Likewise.
* linux-nios2-low.c (the_low_targets): Likewise.
* linux-sparc-low.c (the_low_targets): Likewise.
Since we now rely on PTRACE_EVENT_CLONE being available (added in
Linux 2.5.46), we're relying on NPTL.
This commit removes the support for older LinuxThreads, as well as the
workarounds for vendor 2.4 kernels with NPTL backported.
- Rely on tkill being available.
- Assume gdb doesn't get cancel signals.
- Remove code that checks the LinuxThreads restart and cancel signals
in the inferior.
- Assume that __WALL is available.
- Assume that non-leader threads report WIFEXITED.
- Thus, no longer need to send signal 0 to check whether threads are
still alive.
- Update comments throughout.
Tested on x86_64 Fedora 20, native and gdbserver.
gdb/ChangeLog:
* configure.ac: Remove tkill checks.
* configure, config.in: Regenerate.
* linux-nat.c: Remove HAVE_TKILL_SYSCALL check. Update top level
comments.
(linux_nat_post_attach_wait): Remove 'cloned' parameter. Use
__WALL.
(attach_proc_task_lwp_callback): Don't set the cloned flag.
(linux_nat_attach): Adjust.
(kill_lwp): Remove HAVE_TKILL_SYSCALL check. No longer fall back
to 'kill'.
(linux_handle_extended_wait): Use __WALL. Don't set the cloned
flag.
(wait_lwp): Use __WALL. Update comments.
(running_callback, stop_and_resume_callback): Delete.
(linux_nat_filter_event): Don't stop and resume all lwps. Don't
check if the event LWP has previously exited.
(check_zombie_leaders): Update comments.
(linux_nat_wait_1): Use __WALL.
(kill_wait_callback): Don't handle clone processes separately.
Use __WALL instead.
(linux_thread_alive): Delete.
(linux_nat_thread_alive): Return true as long as the LWP is in the
LWP list.
(linux_nat_update_thread_list): Assume the kernel supports
PTRACE_EVENT_CLONE.
(get_signo): Delete.
(lin_thread_get_thread_signals): Remove LinuxThreads references.
No longer check __pthread_sig_restart / __pthread_sig_cancel in
the inferior.
* linux-nat.h (struct lwp_info) <cloned>: Delete field.
* linux-thread-db.c: Update comments.
(_initialize_thread_db): Remove LinuxThreads references.
* nat/linux-waitpid.c (my_waitpid): No longer emulate __WALL.
Pass down flags unmodified.
* linux-waitpid.h (my_waitpid): Update documentation.
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_kill_one_lwp): Remove references to
LinuxThreads.
(kill_lwp): Remove HAVE_TKILL_SYSCALL check. No longer fall back
to 'kill'.
(linux_init_signals): Delete.
(initialize_low): Adjust.
* thread-db.c (thread_db_init): Remove LinuxThreads reference.
Rename target_ops.arch_setup to .post_create_inferior. In the Linux
hook, continue calling the low arch setup, then also set ptrace flags.
This corrects the possibility of running without flags, demonstrated by
a new test that would fail to catch a fork before.
gdb/gdbserver/ChangeLog:
2015-12-04 Josh Stone <jistone@redhat.com>
* target.h (struct target_ops) <arch_setup>: Rename to ...
(struct target_ops) <post_create_inferior>: ... this.
(target_arch_setup): Rename to ...
(target_post_create_inferior): ... this, calling post_create_inferior.
* server.c (start_inferior): Update target_arch_setup calls to
target_post_create_inferior.
* linux-low.c (linux_low_ptrace_options): Forward declare.
(linux_arch_setup): Update its comment for general use.
(linux_post_create_inferior): New, run arch_setup and setup ptrace.
(struct linux_target_ops): Use linux_post_create_inferior.
* lynx-low.c (struct lynx_target_ops): Update arch_setup stub comment
to post_create_inferior.
* nto-low.c (struct nto_target_ops): Likewise.
* spu-low.c (struct spu_target_ops): Likewise.
* win32-low.c (struct win32_target_ops): Likewise.
gdb/testsuite/ChangeLog:
2015-12-04 Josh Stone <jistone@redhat.com>
* gdb.base/catch-fork-static.exp: New.
This patch removes support for thread events if PTRACE_EVENT_CLONE is not
supported in GDBServer.
Before, on systems that did not support PTRACE_EVENT_CLONE, both GDB and
GDBServer coordinated with libthread_db.so to insert breakpoints at magic
locations in libpthread.so, in order to break at thread creation and thread
death.
Simple software single stepping support was implemented to step over these
breakpoints in case there was no hardware single stepping support. However,
these simple software single stepping implementations were not fit for any other
use as discussed in :
https://sourceware.org/ml/gdb-patches/2015-04/msg01110.html
These too simple implementations conflict with ongoing work to make proper
implementations of software single stepping in GDBServer.
The problem is that if some implementations are correct and others are not and
only there for the thread magic breakpoint, we can't enable features based
solely software single step support since some would be broken.
To keep the incorrect implementations and allow the new proper ones at the same
time we would need to implement fallback code and it quickly becomes ugly and
confusing with multiple checks for legacy software single step or proper
software single step.
However, PTRACE_EVENT_CLONE was first introduced in Linux 2.5.46,
released in November 2002.
So I think it's reasonable to just remove support for kernels that don't support
PTRACE_EVENT_CLONE, and sidestep the libthread_db breakpoints issues entirely.
This thread on the mailling list discusses the issue :
https://sourceware.org/ml/gdb/2015-10/msg00078.html
No regressions, tested on ubuntu 14.04 ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_look_up_symbols): Don't call
linux_supports_traceclone.
* linux-low.h (thread_db_init): Remove use_events argument.
* thread-db.c (thread_db_use_event): Remove global variable.
(struct thread_db) <td_thr_event_enable_p>: Remove field.
(struct thread_db) <td_create_bp>: Remove field.
(thread_db_create_event): Remove function.
(thread_db_enable_reporting): Likewise.
(find_one_thread): Don't check for thread_db_use_events.
(attach_thread): Likewise.
(thread_db_load_search): Remove td_thr_event_enable_p initialization.
(try_thread_db_load_1): Don't check for thread_db_use_events.
(thread_db_init): Remove use_events argument and thread events
handling.
(remove_thread_event_breakpoints): Remove function.
(thread_db_detach): Remove call to remove_thred_event_breakpoints.
Before this patch there was only one call: can_hardware_single_step. Its
implementation was a check on breakpoint_reinsert_addr if NULL it assumed
that the target could hardware single step.
This patch prepares for the case where this is not true anymore.
In order to improve software single stepping in GDBServer the
breakpoint_reinsert_addr operation of targets that had a very simple
software implementation used only for stepping over thread creation events
will be removed.
This will create a case where a target does not support hardware single
step and has the operation breakpoint_reinsert_addr set to NULL, thus
can_hardware_single_step needs to be implemented another way.
A new target operation supports_hardware_single_step is introduced and is
to return true if the target does support such a feature, support for the
feature is manually hardcoded.
Note that the hardware single step support was enabled as per the current
behavior, I did not check if tile for example really has ptrace singlestep
support but since the current implementation assumed it had, I kept it
that way.
No regressions on Ubuntu 14.04 on ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
Compilation tested on: aarch64,arm,bfind,crisv32,m32r,ppc,s390,tic6x,tile,
xtensa.
Not tested : sh.
gdb/gdbserver/ChangeLog:
* linux-aarch64-low.c (aarch64_supports_hardware_single_step):
New function.
(struct linux_target_ops) <supports_hardware_single_step>: Initialize.
* linux-arm-low.c (arm_supports_hardware_single_step): New function.
(struct linux_target_ops) <supports_hardware_single_step>: Initialize.
* linux-bfin-low.c (bfin_supports_hardware_single_step): New function.
(struct linux_target_ops) <bfin_supports_hardware_single_step>:
Initialize.
* linux-crisv32-low.c (cris_supports_hardware_single_step):
New function.
(struct linux_target_ops) <supports_hardware_single_step>: Initialize.
* linux-low.c (can_hardware_single_step): Use
supports_hardware_single_step.
(can_software_single_step): New function.
(start_step_over): Call can_software_single_step.
(linux_supports_hardware_single_step): New function.
(struct target_ops) <supports_software_single_step>: Initialize.
* linux-low.h (struct linux_target_ops)
<supports_hardware_single_step>: Initialize.
* linux-m32r-low.c (m32r_supports_hardware_single_step): New function.
(struct linux_target_ops) <supports_hardware_single_step>: Initialize.
* linux-ppc-low.c (ppc_supports_hardware_single_step): New function.
(struct linux_target_ops) <supports_hardware_single_step> Initialize.
* linux-s390-low.c (s390_supports_hardware_single_step): New function.
(struct linux_target_ops) <supports_hardware_single_step>: Initialize.
* linux-sh-low.c (sh_supports_hardware_single_step): New function.
(struct linux_target_ops) <supports_hardware_single_step>: Initialize.
* linux-tic6x-low.c (tic6x_supports_hardware_single_step): New function.
(struct linux_target_ops) <tic6x_supports_hardware_single_step>:
Initialize.
* linux-tile-low.c (tile_supports_hardware_single_step): New function.
(struct linux_target_ops) <tile_supports_hardware_single_step>:
Initialize.
* linux-x86-low.c (x86_supports_hardware_single_step) New function.
(struct linux_target_ops) <supports_hardware_single_step>: Initialize.
* linux-xtensa-low.c (xtensa_supports_hardware_single_step):
New function.
(struct linux_target_ops) <supports_hardware_single_step>: Initialize.
* target.h (struct target_ops): <supports_software_single_step>:
New field.
(target_supports_software_single_step): New macro.
Without this patch, when doing a software single step, with for example
a conditional breakpoint, gdbserver would wrongly avance the pc of
breakpoint_len and skips an instruction.
This is due to gdbserver assuming that it's hardware single stepping.
When it resumes from the breakpoint address it expects the trap to be
caused by ptrace and if it's rather caused by a software breakpoint
it assumes this is a permanent breakpoint and that it needs to skip
over it.
However when software single stepping, this breakpoint is legitimate as
it's the reinsert breakpoint gdbserver has put in place to break at
the next instruction. Thus gdbserver wrongly advances the pc and skips
an instruction.
This patch fixes this behavior so that gdbserver checks if it is a
reinsert breakpoint from software single stepping. If it is it won't
advance the pc. And if there's no reinsert breakpoint there we assume
then that it's a permanent breakpoint and advance the pc.
Here's a commented log of what would happen before and after the fix on
gdbserver :
/* Here there is a conditional breakpoint at 0x10428 that needs to be
stepped over. */
Need step over [LWP 11204]? yes, found breakpoint at 0x10428
...
/* e7f001f0 is a breakpoint instruction on arm
Here gdbserver writes the software breakpoint we would like to hit
*/
Writing e7f001f0 to 0x0001042c in process 11204
...
Resuming lwp 11220 (continue, signal 0, stop not expected)
pending reinsert at 0x10428
stop pc is 00010428
continue from pc 0x10428
...
/* Here gdbserver hit the software breakpoint that was in place
for the step over */
stop pc is 0001042c
pc is 0x1042c
step-over for LWP 11220.11220 executed software breakpoint
Finished step over.
Could not find fast tracepoint jump at 0x10428 in list (reinserting).
/* Here gdbserver writes back the original instruction */
Writing e50b3008 to 0x0001042c in process 11220
Step-over finished.
Need step over [LWP 11220]? No
/* Here because gdbserver assumes this is a permenant breakpoint it advances
the pc of breakpoint_len, in this case 4 bytes, so we have just skipped
the instruction that was written back here :
Writing e50b3008 to 0x0001042c in process 11220
*/
stop pc is 00010430
pc is 0x10430
Need step over [LWP 11220]? No, no breakpoint found at 0x10430
Proceeding, no step-over needed
proceed_one_lwp: lwp 11220
stop pc is 00010430
This patch fixes this situation and we get the right behavior :
Writing e50b3008 to 0x0001042c in process 11245
Hit a gdbserver breakpoint.
Hit a gdbserver breakpoint.
Step-over finished.
proceeding all threads.
Need step over [LWP 11245]? No
stop pc is 0001042c
pc is 0x1042c
Need step over [LWP 11245]? No, no breakpoint found at 0x1042c
Proceeding, no step-over needed
proceed_one_lwp: lwp 11245
stop pc is 0001042c
pc is 0x1042c
Resuming lwp 11245 (continue, signal 0, stop not expected)
stop pc is 0001042c
continue from pc 0x1042c
It also works if the value at 0x0001042c is a permanent breakpoint.
If so gdbserver will finish the step over, remove the reinserted breakpoint,
resume at that location and on the next SIGTRAP gdbserver will trigger
the advance PC condition as reinsert_breakpoint_inserted_here will be false.
I also tested this against bp-permanent.exp on arm (with a work in progress
software single step patchset) without any regressions.
It's also tested against x86 bp-permanent.exp without any regression.
So both software and hardware single step are tested.
No regressions on Ubuntu 14.04 on ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_wait_1): Fix pc advance condition.
* mem-break.c (reinsert_breakpoint_inserted_here): New function.
* mem-break.h (reinsert_breakpoint_inserted_here): New declaration.
When manually stepping over a permanent breakpoint on ARM we need to fetch the
right breakpoint size based on the current instruction set used.
Since this is not encoded in the stop_pc, the instruction mode needs to be
fetched from the CPSR register.
This is done by introducing a new target operation called :
breakpoint_kind_from_current_state.
For other targets that do not need this, breakpoint_kind_from_pc is used.
No regressions, tested on ubuntu 14.04 ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
gdb/gdbserver/ChangeLog:
* linux-arm-low.c (arm_is_thumb_mode): New function.
(arm_breakpoint_at): Use arm_is_thumb_mode.
(arm_breakpoint_kind_from_current_state): New function.
(struct linux_target_ops) <breakpoint_kind_from_current_state>:
Initialize.
* linux-low.c (linux_wait_1): Call breakpoint_kind_from_current_state.
(linux_breakpoint_kind_from_current_state): New function.
(struct target_ops <breakpoint_kind_from_current_state>: Initialize.
* linux-low.h (struct linux_target_ops)
<breakpoint_kind_from_current_state>: New field.
* target.h (struct target_ops): Likewise.
(target_breakpoint_kind_from_current_state): New macro.
Running killed-outside.exp in with "maint set target-non-stop on"
hangs currently. This test has the inferior process die with a
SIGKILL while stopped. gdbserver gets a SIGCHLD and reacts by
retrieveing the SIGKILL events out of waitpid. But because the
process is not resumed from GDB's perspective, the event is left
pending. When GDB resumes the process afterwards, the process is not
really resumed because it already has the event pending. But nothing
wakes up the event loop to consume the event.
Handle this in the same way nat/linux-nat.c:linux_nat_resume handles
this.
gdb/gdbserver/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* linux-low.c (linux_resume): Wake up the event loop before
returning.
Testing with "maint set target-non-stop on" causes regressions in
tests that rely on TARGET_WAITKIND_NO_RESUMED, which isn't modelled on
the RSP. In real all-stop, gdbserver detects the situation and
reporst error to GDB, and so the tests (e.g.,
gdb.threads/no-unwaited-for-left.exp) at fail quickly. But with
"maint set target-non-stop on", GDB instead hangs forever waiting for
a stop reply that never comes, and so the tests take longer to time
out.
This adds a new "N" stop reply packet that maps 1-1 to
TARGET_WAITKIND_NO_RESUMED.
gdb/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
PR 14618
* NEWS (New remote packets): Mention the N stop reply.
* remote.c (remote_protocol_features): Add "no-resumed" entry.
(remote_query_supported): Report no-resumed+ support.
(remote_parse_stop_reply): Handle 'N'.
(process_stop_reply): Handle TARGET_WAITKIND_NO_RESUMED.
(remote_wait_as): Handle 'N' / TARGET_WAITKIND_NO_RESUMED.
(_initialize_remote): Register "set/show remote
no-resumed-stop-reply" commands.
gdb/doc/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
PR 14618
* gdb.texinfo (Stop Reply Packets): Document the N stop reply.
(Remote Configuration): Add the "set/show remote
no-resumed-stop-reply" to the available settings table.
(General Query Packets): Document the "no-resumed" qSupported
feature.
gdb/gdbserver/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
PR 14618
* linux-low.c (linux_wait_1): If the last resumed thread is gone,
report TARGET_WAITKIND_NO_RESUMED.
* remote-utils.c (prepare_resume_reply): Handle
TARGET_WAITKIND_NO_RESUMED.
* server.c (report_no_resumed): New global.
(handle_query) <qSupported>: Handle "no-resumed+". Report
"no-resumed+" support.
(resume): When the target reports TARGET_WAITKIND_NO_RESUMED, only
return error if the client doesn't support no-resumed events.
(push_stop_notification): New function.
(handle_target_event): Use it. Report TARGET_WAITKIND_NO_RESUMED
events if the client supports them.
gdb/testsuite/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* gdb.threads/no-unwaited-for-left.exp: Remove setup_kfail calls.
killed-outside.exp regresses with "maint set target-non-stop on". The
logs show:
(gdb) continue
Continuing.
infrun: clear_proceed_status_thread (Thread 9028.9028)
infrun: proceed (addr=0xffffffffffffffff, signal=GDB_SIGNAL_DEFAULT)
infrun: proceed: resuming Thread 9028.9028
Sending packet: $Z0,3615a03966,1#4b... Notification received: Stop:X9;process:2344
Packet received: E01
Sending packet: $Z0,3615a13970,1#47...Packet received: E01
Sending packet: $Z0,3615a14891,1#4a...Packet received: E01
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [Thread 9028.9028] at 0x4005e4
Sending packet: $vCont;c:p2344.2344#1a...Packet received: E.target not running.
Sending packet: $qXfer:threads:read::0,fff#03...Packet received: l<threads>\n</threads>\n
Sending packet: $vStopped#55...Packet received: OK
Unexpected vCont reply in non-stop mode: E.target not running.
(gdb) remote_async_inferior_event_handler
infrun: target_wait (-1.0.0, status) =
infrun: 9028.0.0 [process 9028],
infrun: status->kind = signalled, signal = GDB_SIGNAL_KILL
infrun: TARGET_WAITKIND_SIGNALLED
Program terminated with signal SIGKILL, Killed.
The program no longer exists.
infrun: stop_waiting
infrun: clear_step_over_info
infrun: stop_all_threads
remote_thread_exit_events(1)
Note the "Unexpected vCont reply" error.
I traced it to a problem in status_pending_p_callback. It resumes an
LWP when it shouldn't.
gdb/gdbserver/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* linux-low.c (thread_still_has_status_pending_p): Don't check
vCont;t here.
(lwp_resumed): New function.
(status_pending_p_callback): Return early if the LWP is not
supposed to be resumed.
When testing with "maint set target-non-stop on", a few
threading-related tests expose an issue that requires new RSP packets.
Say there are 3 threads running, 1-3. If GDB tries to stop thread 1,
2 and 3, and then waits for their stops, but meanwhile say, thread 2
exits, GDB hangs forever waiting for a stop for thread 2 that won't
ever happen.
This patch fixes the issue by adding support for thread exit events to
the protocol. However, we don't want these always enabled, as they're
useless most of the time, and would slow down remote debugging. So I
made it so that GDB can enable/disable them, and then made gdb do that
around the cases that need it, which currently is only
infrun.c:stop_all_threads.
In turn, if we have thread exit events, then the extra "thread x
exited" traffic slows down attach-many-short-lived-threads.exp enough
that gdb has trouble keeping up with new threads that are spawned
while gdb tries to stop existing ones. To fix that I added support
for the counterpart thread created events too. Enabling those when we
try to stop threads ensures that new threads never get a chance to
themselves start new threads, killing the race.
gdb/doc/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* gdb.texinfo (Remote Configuration): List "set/show remote
thread-events" command in configuration table.
(Stop Reply Packets): Document "T05 create" stop
reason and 'w' stop reply.
(General Query Packets): Document QThreadEvents packet. Document
QThreadEvents qSupported feature.
gdb/gdbserver/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* linux-low.c (handle_extended_wait): Assert that the LWP's
waitstatus is TARGET_WAITKIND_IGNORE. If GDB wants to hear about
thread create events, leave the new child's status pending.
(linux_low_filter_event): If GDB wants to hear about thread exit
events, leave the LWP marked dead and don't delete it.
(linux_wait_for_event_filtered): Don't check for thread exit.
(filter_exit_event): New function.
(linux_wait_1): Use it, when returning an exit event.
(linux_resume_one_lwp_throw): Assert that the LWP's
waitstatus is TARGET_WAITKIND_IGNORE.
* remote-utils.c (prepare_resume_reply): Handle
TARGET_WAITKIND_THREAD_CREATED and TARGET_WAITKIND_THREAD_EXITED.
* server.c (report_thread_events): New global.
(handle_general_set): Handle QThreadEvents.
(handle_query) <qSupported>: Handle and report QThreadEvents+;
(handle_target_event): Handle TARGET_WAITKIND_THREAD_CREATED and
TARGET_WAITKIND_THREAD_EXITED.
* server.h (report_thread_events): Declare.
gdb/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* NEWS (New commands): Mention "set/show remote thread-events"
commands.
(New remote packets): Mention thread created/exited stop reasons
and QThreadEvents packet.
* infrun.c (disable_thread_events): New function.
(stop_all_threads): Disable/enable thread create/exit events.
Handle TARGET_WAITKIND_THREAD_EXITED.
(handle_inferior_event_1): Handle TARGET_WAITKIND_THREAD_CREATED
and TARGET_WAITKIND_THREAD_EXITED.
* remote.c (remove_child_of_pending_fork): Also remove threads of
threads that have TARGET_WAITKIND_THREAD_EXITED events.
(remote_parse_stop_reply): Handle "create" magic register. Handle
'w' stop reply.
(initialize_remote): Install remote_thread_events as
to_thread_events target hook.
(remote_thread_events): New function.
* target-delegates.c: Regenerate.
* target.c (target_thread_events): New function.
* target.h (struct target_ops) <to_thread_events>: New field.
(target_thread_events): Declare.
* target/waitstatus.c (target_waitstatus_to_string): Handle
TARGET_WAITKIND_THREAD_CREATED and TARGET_WAITKIND_THREAD_EXITED.
* target/waitstatus.h (enum target_waitkind)
<TARGET_WAITKIND_THREAD_CREATED, TARGET_WAITKIND_THREAD_EXITED):
New values.
Running attach-many-short-lived-threads.exp with the extended-remote
board with "maint set target-non-stop on" times out -- the attach
never completes. Enabling infrun debug logs, we see that GDB is stuck
stopping all threads:
infrun: target_wait (-1.0.0, status) =
infrun: 1639.22213.0 [Thread 1639.22213],
infrun: status->kind = stopped, signal = GDB_SIGNAL_0
infrun: Thread 1639.22260 not executing
infrun: Thread 1639.22256 not executing
infrun: Thread 1639.22258 not executing
infrun: Thread 1639.22257 not executing
infrun: Thread 1639.22259 not executing
infrun: Thread 1639.22255 not executing
infrun: Thread 1639.22253 executing, already stopping
infrun: Thread 1639.22251 executing, already stopping
infrun: Thread 1639.22252 executing, already stopping
infrun: Thread 1639.22250 executing, already stopping
infrun: Thread 1639.22254 executing, already stopping
infrun: Thread 1639.22247 executing, already stopping
infrun: Thread 1639.22213 not executing
infrun: Thread 1639.22207 not executing
infrun: Thread 1639.22201 not executing
infrun: Thread 1639.22219 not executing
infrun: Thread 1639.1639 not executing
** HANG HERE **
GDB is waiting for the stop replies of any of those "already stopping"
threads. Take 22253 for example. On the gdbserver logs we see:
...
resume_stop request for LWP 22253
stopping LWP 22253
Sending sigstop to lwp 22253
linux_resume done
...
and:
my_waitpid (-1, 0x40000001)
my_waitpid (-1, 0x80000001): status(3057f), 22253
LWFE: waitpid(-1, ...) returned 22253, ERRNO-OK
LLW: waitpid 22253 received Trace/breakpoint trap (stopped)
pc is 0x3615ef4ce1
HEW: Got clone event from LWP 22253, new child is LWP 22259
but from here on, we never see any other event for LWP 22253. In
particular, we never see the expected SIGSTOP (from "Sending sigstop"
above). The issue is that linux_resume_stopped_resumed_lwps never
re-resumes the 22253 after the clone event.
gdb/gdbserver/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* linux-low.c (resume_stopped_resumed_lwps): Don't check whether
the thread's last_resume_kind was resume_stop.
With "maint set target-non-stop on", the attach tests occasionally
crash gdbserver.
Basically, gdb attaches with vAttach;PID, and then shortly after reads
the xml target description for that process, to figure out the
process' architecture. On the gdbserver side, the target description
is only filled in when the first process/thread in the thread group
reports its initial PTRACE_ATTACH SIGSTOP. So if GDB is fast enough,
it can read the target description _before_ that initial stop, and
then gdbserver dies dereferencing a NULL tdesc pointer.
gdb/gdbserver/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* linux-low.c (linux_attach): In non-stop mode, wait for one stop
before returning.
This patch adds support for thread names in the remote protocol, and
updates gdb/gdbserver to use it. The information is added to the XML
description sent in response to the qXfer:threads:read packet.
gdb/ChangeLog:
* linux-nat.c (linux_nat_thread_name): Replace implementation by call
to linux_proc_tid_get_name.
* nat/linux-procfs.c (linux_proc_tid_get_name): New function,
implementation inspired by linux_nat_thread_name.
* nat/linux-procfs.h (linux_proc_tid_get_name): New declaration.
* remote.c (struct private_thread_info) <name>: New field.
(free_private_thread_info): Free name field.
(remote_thread_name): New function.
(thread_item_t) <name>: New field.
(clear_threads_listing_context): Free name field.
(start_thread): Get name xml attribute.
(thread_attributes): Add "name" attribute.
(remote_update_thread_list): Copy name field.
(init_remote_ops): Assign remote_thread_name callback.
* target.h (target_thread_name): Update comment.
* NEWS: Mention remote thread name support.
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_target_ops): Use linux_proc_tid_get_name.
* server.c (handle_qxfer_threads_worker): Refactor to include thread
name in reply.
* target.h (struct target_ops) <thread_name>: New field.
(target_thread_name): New macro.
gdb/doc/ChangeLog:
* gdb.texinfo (Thread List Format): Mention thread names.
The target_process_qsupported method is called for each qSupported
feature that the common code does not recognize. The only current
implementation, for x86 Linux (x86_linux_process_qsupported), assumes
that it either is called with the "xmlRegisters=i386" feature, or that
it is isn't called at all, indicating the connected GDB predates x86
XML descriptions.
That's a bad assumption however. If GDB sends in a new/unknown (to
core gdbserver) feature after "xmlRegisters=i386", say, something like
qSupported:xmlRegisters=i386;UnknownFeature+, then when
target_process_qsupported is called for "UnknownFeature+",
x86_linux_process_qsupported clears the 'use_xml' global and calls
x86_linux_update_xmltarget, and gdbserver ends up _not_ reporting a
XML description...
This commit changes the target_process_qsupported API to instead pass
down a vector of unprocessed qSupported features in one go.
(There's an early call to target_process_qsupported(NULL) that
indicates "starting qSupported processing". There's no matching call
to mark the end of processing, though. I first fixed this by passing
(char *)-1 to indicate that, and adjusted the x86 backend to only
clear 'use_xml' when qSupported processing starts, and then only call
x86_linux_update_xmltarget() when (char *)-1 was passed. However, I
wasn't that happy with the hack and came up this alternative version.)
gdb/gdbserver/ChangeLog:
2015-11-19 Pedro Alves <palves@redhat.com>
* linux-low.c (linux_process_qsupported): Change prototype.
Adjust.
* linux-low.h (struct linux_target_ops) <process_qsupported>:
Change prototype.
* linux-x86-low.c (x86_linux_process_qsupported): Change prototype
and adjust to loop over all features.
* server.c (handle_query) <qSupported>: Adjust to call
target_process_qsupported once, passing it a vector of unprocessed
features.
* target.h (struct target_ops) <process_qsupported>: Change
prototype.
(target_process_qsupported): Adjust.
Fixes:
../../../src/gdb/gdbserver/linux-low.c: In function ‘int linux_low_read_btrace(btrace_target_info*, buffer*, int)’:
../../../src/gdb/gdbserver/linux-low.c:6827:48: error: invalid conversion from ‘int’ to ‘btrace_read_type’ [-fpermissive]
err = linux_read_btrace (&btrace, tinfo, type);
^
In file included from ../../../src/gdb/gdbserver/linux-low.c:98:0:
../../../src/gdb/gdbserver/../nat/linux-btrace.h:116:26: error: initializing argument 3 of ‘btrace_error linux_read_btrace(btrace_data*, btrace_target_info*, btrace_read_type)’ [-fpermissive]
extern enum btrace_error linux_read_btrace (struct btrace_data *btrace,
^
The cyclic dependency the comment talks about is no longer relevant:
https://sourceware.org/ml/gdb-patches/2015-10/msg00643.html
gdb/gdbserver/ChangeLog:
2015-10-29 Pedro Alves <palves@redhat.com>
* linux-low.c (linux_low_read_btrace): Change type of 'type'
parameter.
* server.c (handle_qxfer_btrace): Change type of 'type'
local.
* target.h (struct target_ops) <read_btrace>: Change type of
'type' parameter. Update comment.
gdb/ChangeLog:
* nat/linux-nat.h (__SIGRTMIN): Move here from gdbserver/linux-low.c.
gdb/gdbserver/ChangeLog:
* linux-low.c (__SIGRTMIN): Move to nat/linux-nat.h.
gdb/ChangeLog:
* common/gdb_wait.h (W_STOPCODE): Define, moved here from
gdbserver/linux-low.c.
(WSETSTOP): Simplify.
gdb/gdbserver/ChangeLog:
* linux-low.c (W_STOPCODE): Moved to common/gdb_wait.h.
This patch moves default_breakpoint_kind_from_pc to target.c and creates a macro
so that all targets can easily use it.
This allows the breakpoint_kind_from_pc operation to be left unimplemented in
targets that do not need it.
This is preparation to fix the win32/nto/spu build that was broken by this
patch: https://sourceware.org/ml/gdb-patches/2015-10/msg00369.html
No regression on Ubuntu 14.04 x86-64 with gdbserver-{native-extended}
gdb/gdbserver/ChangeLog:
* linux-low.c (default_breakpoint_kind_from_pc): Move to target.c.
* mem-break.c (set_breakpoint_at): Use target_breakpoint_kind_from_pc.
* target.c (default_breakpoint_kind_from_pc): Moved from linux-low.c
* target.h (target_breakpoint_kind_from_pc): New macro.
This patch fixes a regression introduced by :
https://sourceware.org/ml/gdb-patches/2015-10/msg00369.html
Tests : gdb.trace/trace-break.exp and gdb.trace/trace-mt.exp would fail on x86
with gdbserver-{native,extended}.
Before this patch, the breakpoint kind set by GDB with a Z packet and the one
set in the case of a tracepoint would be inconsistent on targets that did not
implement breakpoint_kind_from_pc. On x86 for example a breakpoint set by GDB
would have a kind of 1 but a breakpoint set by a tracepoint would have a kind of
0.
This created a missmatch when trying to insert a tracepoint and a breakpoint at
the same location. One of the two breakpoints would be removed with debug
message : "Inconsistent breakpoint kind".
This patch fixes the issue by changing the default 0 breakpoint kind to be
the size of the breakpoint according to sw_breakpoint_from_kind.
The default breakpoint kind must be the breakpoint length to keep consistency
between breakpoints set via GDB and the ones set internally by GDBServer.
No regression on Ubuntu 14.04 x86-64 with gdbserver-{native-extended}
gdb/gdbserver/ChangeLog:
* linux-low.c (default_breakpoint_kind_from_pc): New function.
(linux_breakpoint_kind_from_pc): Use default_breakpoint_kind_from_pc for
the default breakpoint kind.
There's two ways to set breakpoints in GDBServer.
- GDBServer setting its own breakpoints, through API set_breakpoint_at.
- GDBServer setting breakpoints according to the information in Z
packets, through API set_gdb_breakpoint.
Before this patch the breakpoint kinds were a concept unique to GDB and Z
packets, as GDBServer never had to set different kinds of breakpoint on its
own.
This patch teaches GDBServer to handle breakpoint kinds for its own
breakpoints. It generalizes the breakpoint kind as per Z packets to
represent different kinds of breakpoints directly set by GDBServer also.
GDBServer now querys breakpoint_kind_from_pc to know what breakpoint kind to
set on its own.
As the kind is now a differentiating factor equivalent to size for the
breakpoint struct and that it's size can be queried using
sw_breakpoint_from_kind, the size field has been replaced with the kind field.
All references to size are now replaced by kind or a call to bp_size that wraps
sw_breakpoing_from_kind and returns the size of the breakpoint in memory.
To fetch the software breakpoint data bp_opcode is called and wraps the
sw_breakpoint_from_kind call.
No regressions on Ubuntu 14.04 on ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
gdb/gdbserver/ChangeLog:
* linux-low.c (initialize_low): Ajdust for breakpoint global variables
removal.
* mem-break.c : Remove breakpoint_data/breakpoint_len global variables.
(struct raw_breakpoint) <size>: Remove.
(struct raw_breakpoint) <kind>: Add.
(bp_size): New function.
(bp_opcode): Likewise.
(find_raw_breakpoint_at): Adjust for kind.
(insert_memory_breakpoint): Adjust for kind call bp_size,bp_opcode.
(remove_memory_breakpoint): Adjust for kind call bp_size.
(set_raw_breakpoint_at): Adjust for kind.
(set_breakpoint): Likewise.
(set_breakpoint_at): Call breakpoint_kind_from_pc.
(delete_raw_breakpoint): Adjust for kind.
(delete_breakpoint): Likewise.
(find_gdb_breakpoint): Likewise.
(set_gdb_breakpoint_1): Likewise.
(set_gdb_breakpoint): Likewise.
(delete_gdb_breakpoint_1): Likewise.
(delete_gdb_breakpoint): Likewise.
(uninsert_raw_breakpoint): Likewise.
(reinsert_raw_breakpoint): Likewise.
(set_breakpoint_data): Remove.
(validate_inserted_breakpoint): Adjust for kind call bp_size,bp_opcode.
(check_mem_read): Adjust for kind call bp_size.
(check_mem_write): Adjust for kind call bp_size,bp_opcode.
(clone_one_breakpoint): Adjust for kind.
* mem-break.h (set_gdb_breakpoint): Likewise.
(delete_gdb_breakpoint): Likewise.
* server.c (process_serial_event): Likewise.
This patch is in preparation for software breakpoints on ARM linux. It
refactors breakpoint and breakpoint_len into breakpoint_kind_from_pc and
sw_breakpoint_from kind to prepare the case where we have multiple types of
breakpoints.
Kind is the type of breakpoint (hardware or software) to be inserted, usually it
is the lenght of the software breakpoint but can be something else depending on
the target.
This patch introduces the linux_target_ops breakpoint_kind_from_pc and
sw_breakpoint_from_kind.
breakpoint_kind_from_pc returns the breakpoint kind and adjusts the PC to the
real memory location in case a flag was present in the PC. E.g the instruction
mode on ARM.
sw_breakpoint_from_kind returns the software breakpoint for this kind as a
string of bytes, the length of the breakpoint is adjusted for the breakpoint's
size in memory.
For targets that have only one kind of breakpoint, the default value 0 is
returned by linux_breakpoint_kind_from_pc so that not all targets need to
implement the breakpoint_kind_from_pc operation.
No regressions, tested on Ubuntu 14.04 on ARMv7 and x86
With gdbserver-{native,extended} / { -marm -mthumb }
Also since the target_ops have been changed compilation was tested on
affected archs namely : aarch64, arm, bfin, cris, crisv32, m32r,
m68k, mips, nios2, ppc, s390, sparc, tic6x, tile, x86, steins.
Not tested : sh
gdb/gdbserver/ChangeLog:
* linux-aarch64-low.c (aarch64_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-arm-low.c (arm_breakpoint_kind_from_pc): New function.
(arm_sw_breakpoint_from_kind): New function.
* linux-bfin-low.c (bfin_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-cris-low.c (cris_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-crisv32-low.c (cris_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-low.c (linux_wait_1): Call breakpoint_kind_from_pc
and sw_breakpoint_from_kind to increment the pc.
(linux_breakpoint_kind_from_pc): New function.
(linux_sw_breakpoint_from_kind): New function.
(struct target_ops) <sw_breakpoint_from_kind>: Initialize field.
(initialize_low): Call breakpoint_kind_from_pc and
sw_breakpoint_from_kind to replace breakpoint_data/len.
* linux-low.h (struct linux_target_ops) <breakpoint_kind_from_pc>:
New field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Likewise.
* linux-m32r-low.c (m32r_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-m68k-low.c (m68k_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-mips-low.c (mips_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-nios2-low.c (nios2_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-ppc-low.c (ppc_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-s390-low.c (s390_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-sh-low.c (sh_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-sparc-low.c (sparc_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-tic6x-low.c (tic6x_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-tile-low.c (tile_sw_breakpoint_from_kind): New function.
* linux-x86-low.c (x86_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-xtensa-low.c (xtensa_sw_breakpoint_from_kind) New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
In my patch https://sourceware.org/ml/gdb-patches/2015-04/msg01110.html
a new target_ops hook supports_conditional_breakpoints was added to
disable conditional breakpoints if target doesn't have hardware single
step. This patch is to generalize this hook from
supports_conditional_breakpoints to supports_hardware_single_step,
so that the following patch can use it.
gdb/gdbserver:
2015-09-15 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_supports_conditional_breakpoints): Rename
it to ...
(linux_supports_hardware_single_step): ... New function.
(linux_target_ops): Update.
* lynx-low.c (lynx_target_ops): Set field
supports_hardware_single_step to target_can_do_hardware_single_step.
* nto-low.c (nto_target_ops): Likewise.
* spu-low.c (spu_target_ops): Likewise.
* win32-low.c (win32_target_ops): Likewise.
* target.c (target_can_do_hardware_single_step): New function.
* target.h (struct target_ops) <supports_conditional_breakpoints>:
Remove. <supports_hardware_single_step>: New field.
(target_supports_conditional_breakpoints): Remove.
(target_supports_hardware_single_step): New macro.
(target_can_do_hardware_single_step): Declare.
* server.c (handle_query): Use target_supports_hardware_single_step
instead of target_supports_conditional_breakpoints.
This patch implements support for exec events on extended-remote Linux
targets. Follow-exec-mode and rerun behave as expected. Catchpoints and
test updates are implemented in subsequent patches.
This patch was derived from a patch posted last October:
https://sourceware.org/ml/gdb-patches/2014-10/msg00877.html.
It was originally based on some work done by Luis Machado in 2013.
IMPLEMENTATION
----------------
Exec events are enabled via ptrace options.
When an exec event is detected by gdbserver, the existing process
data, along with all its associated lwp and thread data, is deleted
and replaced by data for a new single-threaded process. The new
process data is initialized with the appropriate parts of the state
of the execing process. This approach takes care of several potential
pitfalls, including:
* deleting the data for an execing non-leader thread before any
wait/sigsuspend occurs
* correctly initializing the architecture of the execed process
We then report the exec event using a new RSP stop reason, "exec".
When GDB receives an "exec" event, it saves the status in the event
structure's target_waitstatus field, like what is done for remote fork
events. Because the original and execed programs may have different
architectures, we skip parsing the section of the stop reply packet
that contains register data. The register data will be retrieved
later after the inferior's architecture has been set up by
infrun.c:follow_exec.
At that point the exec event is handled by the existing event handling
in GDB. However, a few changes were necessary so that
infrun.c:follow_exec could accommodate the remote target.
* Where follow-exec-mode "new" is handled, we now call
add_inferior_with_spaces instead of add_inferior with separate calls
to set up the program and address spaces. The motivation for this
is that add_inferior_with_spaces also sets up the initial architecture
for the inferior, which is needed later by target_find_description
when it calls target_gdbarch.
* We call a new target function, target_follow_exec. This function
allows us to store the execd_pathname in the inferior, instead of
using the static string remote_exec_file from remote.c. The static
string didn't work for follow-exec-mode "new", since once you switched
to the execed program, the original remote exec-file was lost. The
execd_pathname is now stored in the inferior's program space as a
REGISTRY field. All of the requisite mechanisms for this are
defined in remote.c.
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_mourn): Static declaration.
(linux_arch_setup): Move in front of
handle_extended_wait.
(linux_arch_setup_thread): New function.
(handle_extended_wait): Handle exec events. Call
linux_arch_setup_thread. Make event_lwp argument a
pointer-to-a-pointer.
(check_zombie_leaders): Do not check stopped threads.
(linux_low_ptrace_options): Add PTRACE_O_TRACEEXEC.
(linux_low_filter_event): Add lwp and thread for exec'ing
non-leader thread if leader thread has been deleted.
Refactor code into linux_arch_setup_thread and call it.
Pass child lwp pointer by reference to handle_extended_wait.
(linux_wait_for_event_filtered): Update comment.
(linux_wait_1): Prevent clobbering exec event status.
(linux_supports_exec_events): New function.
(linux_target_ops) <supports_exec_events>: Initialize new member.
* lynx-low.c (lynx_target_ops) <supports_exec_events>: Initialize
new member.
* remote-utils.c (prepare_resume_reply): New stop reason 'exec'.
* server.c (report_exec_events): New global variable.
(handle_query): Handle qSupported query for exec-events feature.
(captured_main): Initialize report_exec_events.
* server.h (report_exec_events): Declare new global variable.
* target.h (struct target_ops) <supports_exec_events>: New
member.
(target_supports_exec_events): New macro.
* win32-low.c (win32_target_ops) <supports_exec_events>:
Initialize new member.
gdb/ChangeLog:
* infrun.c (follow_exec): Use process-style ptid for
exec message. Call add_inferior_with_spaces and
target_follow_exec.
* nat/linux-ptrace.c (linux_supports_traceexec): New function.
* nat/linux-ptrace.h (linux_supports_traceexec): Declare.
* remote.c (remote_pspace_data): New static variable.
(remote_pspace_data_cleanup): New function.
(get_remote_exec_file): New function.
(set_remote_exec_file_1): New function.
(set_remote_exec_file): New function.
(show_remote_exec_file): New function.
(remote_exec_file): Delete static variable.
(anonymous enum) <PACKET_exec_event_feature> New
enumeration constant.
(remote_protocol_features): Add entry for exec-events feature.
(remote_query_supported): Add client side of qSupported query
for exec-events feature.
(remote_follow_exec): New function.
(remote_parse_stop_reply): Handle 'exec' stop reason.
(extended_remote_run, extended_remote_create_inferior): Call
get_remote_exec_file and set_remote_exec_file_1.
(init_extended_remote_ops) <to_follow_exec>: Initialize new
member.
(_initialize_remote): Call
register_program_space_data_with_cleanup. Call
add_packet_config_cmd for remote exec-events feature.
Modify call to add_setshow_string_noescape_cmd for exec-file
to use new functions set_remote_exec_file and
show_remote_exec_file.
* target-debug.h, target-delegates.c: Regenerated.
* target.c (target_follow_exec): New function.
* target.h (struct target_ops) <to_follow_exec>: New member.
(target_follow_exec): Declare new function.
For the BTS recording format, we sometimes get a FROM->TO record where the
FROM address lies in the kernel and the TO address lies in user space at
whatever address the user process was resumed.
GDB has a heuristic to filter out such records based on looking at the most
significant bit in the PC. This works fine for 64-bit systems but it doesn't
always work for 32-bit systems. Libraries that are loaded at fairly high
addresses might be mistaken for kernel code and branches inside the library
are filtered out.
Change the heuristic to (again heuristically) try to determine the lowest
address in kernel space. Any PC that is smaller than that should be in
user space.
On today's systems, there should be a symbol "_text" at that address.
Read /proc/kallsyms and search for that symbol.
It is not guaranteed that /proc/kallsyms is readable on all systems. On
64-bit systems, we fall back to check the most significant bit. On 32-bit
systems, we refrain from filtering out addresses.
The filtering should really be done by the kernel. And it soon will be:
https://lkml.org/lkml/2015/8/31/212.
gdb/
* nat/linux-btrace.h (struct btrace_target_info) <ptr_bits>: Remove.
* nat/linux-btrace.c: Include filestuff.h and inttypes.h.
Remove include of sys/utsname.h.
(linux_determine_kernel_ptr_bits): Remove.
(linux_determine_kernel_start): New.
(perf_event_is_kernel_addr): Remove tinfo argument. Update users.
Update check.
(perf_event_skip_bts_record): Remove tinfo argument. Update users.
(linux_enable_bts, linux_enable_pt): Remove tinfo->ptr_bits
initialization.
* x86-linux-nat.c (x86_linux_enable_btrace): Remove ptr_bits
assignment.
gdbserver/
* linux-low.c (linux_low_enable_btrace): Remove.
(linux_target_ops): Replace linux_low_enable_btrace with
linux_enable_btrace.
Yao Qi