Some unaligned watchpoints were currently missed.
On old kernels as specified in
kernel RFE: aarch64: ptrace: BAS: Support any contiguous range (edit)
https://sourceware.org/bugzilla/show_bug.cgi?id=20207
after this patch some other unaligned watchpoints will get reported as false
positives.
With new kernels all the watchpoints should work exactly.
There may be a regresion that it now less merges watchpoints so that with
multiple overlapping watchpoints it may run out of the 4 hardware watchpoint
registers. But as discussed in the original thread GDB needs some generic
watchpoints merging framework to be used by all the target specific code.
Even current FSF GDB code does not merge it perfectly. Also with the more
precise watchpoints one can technically merge them less. And I do not think
it matters too much to improve mergeability only for old kernels.
Still even on new kernels some better merging logic would make sense.
There remains one issue:
kernel-4.15.14-300.fc27.armv7hl
FAIL: gdb.base/watchpoint-unaligned.exp: continue
FAIL: gdb.base/watchpoint-unaligned.exp: continue
(gdb) continue
Continuing.
Unexpected error setting watchpoint: Invalid argument.
(gdb) FAIL: gdb.base/watchpoint-unaligned.exp: continue
But that looks as a kernel bug to me.
(1) It is not a regression by this patch.
(2) It is unrelated to this patch.
gdb/ChangeLog
2018-05-04 Jan Kratochvil <jan.kratochvil@redhat.com>
Pedro Alves <palves@redhat.com>
PR breakpoints/19806 and support for PR external/20207.
* NEWS: Mention Aarch64 watchpoint improvements.
* aarch64-linux-nat.c (aarch64_linux_stopped_data_address): Fix missed
watchpoints and PR external/20207 watchpoints.
* nat/aarch64-linux-hw-point.c
(kernel_supports_any_contiguous_range): New.
(aarch64_watchpoint_offset): New.
(aarch64_watchpoint_length): Support PR external/20207 watchpoints.
(aarch64_point_encode_ctrl_reg): New parameter offset, new asserts.
(aarch64_point_is_aligned): Support PR external/20207 watchpoints.
(aarch64_align_watchpoint): New parameters aligned_offset_p and
next_addr_orig_p. Support PR external/20207 watchpoints.
(aarch64_downgrade_regs): New.
(aarch64_dr_state_insert_one_point): New parameters offset and
addr_orig.
(aarch64_dr_state_remove_one_point): Likewise.
(aarch64_handle_breakpoint): Update caller.
(aarch64_handle_aligned_watchpoint): Likewise.
(aarch64_handle_unaligned_watchpoint): Support addr_orig and
aligned_offset.
(aarch64_linux_set_debug_regs): Remove const from state. Call
aarch64_downgrade_regs.
(aarch64_show_debug_reg_state): Print also dr_addr_orig_wp.
* nat/aarch64-linux-hw-point.h (DR_CONTROL_LENGTH): Rename to ...
(DR_CONTROL_MASK): ... this.
(struct aarch64_debug_reg_state): New field dr_addr_orig_wp.
(unsigned int aarch64_watchpoint_offset): New prototype.
(aarch64_linux_set_debug_regs): Remove const from state.
* utils.c (align_up, align_down): Move to ...
* common/common-utils.c (align_up, align_down): ... here.
* utils.h (align_up, align_down): Move to ...
* common/common-utils.h (align_up, align_down): ... here.
gdb/gdbserver/ChangeLog
2018-05-04 Jan Kratochvil <jan.kratochvil@redhat.com>
Pedro Alves <palves@redhat.com>
* linux-aarch64-low.c (aarch64_stopped_data_address):
Likewise.
gdb/testsuite/ChangeLog
2018-05-04 Jan Kratochvil <jan.kratochvil@redhat.com>
Pedro Alves <palves@redhat.com>
PR breakpoints/19806 and support for PR external/20207.
* gdb.base/watchpoint-unaligned.c: New file.
* gdb.base/watchpoint-unaligned.exp: New file.
$ make check-headers CHECK_HEADERS="nat/aarch64-linux-hw-point.h"
...
../../binutils-gdb/gdb/nat/aarch64-linux-hw-point.h:169:37: error: use of enum 'target_hw_bp_type' without previous declaration
int aarch64_handle_breakpoint (enum target_hw_bp_type type, CORE_ADDR addr,
^
gdb:
2017-01-06 Yao Qi <yao.qi@linaro.org>
* nat/aarch64-linux-hw-point.h: Include break-common.h.
This applies the second part of GDB's End of Year Procedure, which
updates the copyright year range in all of GDB's files.
gdb/ChangeLog:
Update copyright year range in all GDB files.
The problem here is ARMv8.1 (and ARMv8.2) define a
different debug version than ARMv8 (7 and 8 respectively).
This fixes hw watchpoints and breakpoints by checking
for those debug versions too.
Committed as obvious after a test on aarch64-linux-gnu
(on a ThunderX machine which has ARMv8.1 support enabled).
ChangeLog:
* nat/aarch64-linux-hw-point.c
(aarch64_linux_get_debug_reg_capacity): Handle
ARMv8.1 and ARMv8.2 debug versions.
* nat/aarch64-linux-hw-point.h
(AARCH64_DEBUG_ARCH_V8_1): New define.
(AARCH64_DEBUG_ARCH_V8_2): New define.
Signed-off-by: Andrew Pinski <apinski@cavium.com>
Nowadays, if user requests HW watchpoint to monitor a large memory area
or unaligned area, aarch64 GDB will split into multiple aligned areas,
and use multiple debugging registers to watch them. However, the
registers are not updated in a transaction way. GDBserver doesn't revert
updates in previous iterations if some debugging registers fail to update
due to some reason, like no free debugging registers available, in the
latter iteration. For example, if we have a char buf[34], and watch buf
in gdb,
(gdb) watch buf
Hardware watchpoint 2: buf
(gdb) c
Continuing.
infrun: clear_proceed_status_thread (Thread 13466)
infrun: proceed (addr=0xffffffffffffffff, signal=GDB_SIGNAL_DEFAULT)
infrun: step-over queue now empty
infrun: resuming [Thread 13466] for step-over
Sending packet: $m410838,22#35...Packet received: 00000000000000000000000000000000000000000000000000000000000000000000
infrun: skipping breakpoint: stepping past insn at: 0x400524
infrun: skipping breakpoint: stepping past insn at: 0x400524
Sending packet: $Z2,410838,22#80...Packet received: E01 <----- [1]
Packet Z2 (write-watchpoint) is supported
Sending packet: $Z0,7fb7fe0a8c,4#43...Packet received: OK
Warning:
Could not insert hardware watchpoint 2.
Could not insert hardware breakpoints:
You may have requested too many hardware breakpoints/watchpoints.
GDB receives E01 for Z2 packet [1] but GDBserver updates the debugging
register status,
insert_point (addr=0x00410838, len=34, type=hw-write-watchpoint):
BREAKPOINTs:
BP0: addr=0x0, ctrl=0x00000000, ref.count=0
BP1: addr=0x0, ctrl=0x00000000, ref.count=0
BP2: addr=0x0, ctrl=0x00000000, ref.count=0
BP3: addr=0x0, ctrl=0x00000000, ref.count=0
BP4: addr=0x0, ctrl=0x00000000, ref.count=0
BP5: addr=0x0, ctrl=0x00000000, ref.count=0
WATCHPOINTs:
WP0: addr=0x410850, ctrl=0x00001ff5, ref.count=1
WP1: addr=0x410848, ctrl=0x00001ff5, ref.count=1
WP2: addr=0x410840, ctrl=0x00001ff5, ref.count=1
WP3: addr=0x410838, ctrl=0x00001ff5, ref.count=1
four debugging registers can not monitor 34-byte long area, so the last
iteration of updating debugging register state fails but previous
iterations succeed. This makes GDB think no HW watchpoint is inserted
but some debugging registers are used.
This problem was exposed by "watch buf" gdb.base/watchpoint.exp with
aarch64 GDBserver debugging arm 32-bit program. The buf is 30-byte long
but 4-byte aligned, and four debugging registers can't cover 34-byte
(extend 4 bytes to be 8-byte aligned) area. However, this problem
does exist on non-multi-arch debugging scenario as well.
This patch moves code in aarch64_linux_region_ok_for_hw_watchpoint to
aarch64_linux_region_ok_for_watchpoint in nat/aarch64-linux-hw-point.c.
Then, checks with aarch64_linux_region_ok_for_watchpoint, like what we
are doing in GDB. If the region is OK, call aarch64_handle_watchpoint.
Regression tested on aarch64 with both 64-bit program and 32-bit
program. Some fails in gdb.base/watchpoint.exp are fixed.
gdb:
2015-09-03 Yao Qi <yao.qi@linaro.org>
* aarch64-linux-nat.c (aarch64_linux_region_ok_for_hw_watchpoint):
Move code to aarch64_linux_region_ok_for_watchpoint. Call
aarch64_linux_region_ok_for_watchpoint.
* nat/aarch64-linux-hw-point.c (aarch64_linux_region_ok_for_watchpoint):
New function.
* nat/aarch64-linux-hw-point.h (aarch64_linux_region_ok_for_watchpoint):
Declare it.
gdb/gdbserver:
2015-09-03 Yao Qi <yao.qi@linaro.org>
* linux-aarch64-low.c (aarch64_insert_point): Call
aarch64_handle_watchpoint if aarch64_linux_region_ok_for_watchpoint
returns true.
There are also some duplication on getting HW watchpoint/breakpoint
registers info between GDB and GDBserver. This patch moves them
to nat/aarch64-linux-hw-point.c.
Note that ENABLE_NLS is not defined in GDBserver, so it should be OK
to use _( markup.
gdb:
2015-07-21 Yao Qi <yao.qi@linaro.org>
* aarch64-linux-nat.c (aarch64_linux_get_debug_reg_capacity):
Move it to nat/aarch64-linux-hw-point.c.
(aarch64_linux_child_post_startup_inferior): Update.
* nat/aarch64-linux-hw-point.c (aarch64_linux_get_debug_reg_capacity):
New function.
* nat/aarch64-linux-hw-point.h (aarch64_linux_get_debug_reg_capacity):
Declare it.
gdb/gdbserver:
2015-07-21 Yao Qi <yao.qi@linaro.org>
* linux-aarch64-low.c (aarch64_arch_setup): Remove code and call
aarch64_linux_get_debug_reg_capacity.
This patch is to fix two ARI warnings for nat/aarch64-linux-hw-point.{c,h}.
gdb:
2015-07-20 Yao Qi <yao.qi@linaro.org>
* nat/aarch64-linux-hw-point.c (aarch64_handle_unaligned_watchpoint):
Re-indent the code.
* nat/aarch64-linux-hw-point.h: Use ULONGEST rather than
"unsigned long long".
When I look at test fails related to watchpoint on aarch64-linux,
I find there are some code duplicates between GDB and GDBserver.
This patch is to move some of them to a nat/aarch64-linux-hw-point.{h,c}.
The only change I do is about the dr_changed_t typedef, which was
ULONGEST in GDB and 'unsigned long long' in GDBserver. Each bit
of dr_changed_t represents a status of each HW breakpoint or
watchpoint register, and the max number of HW breakpoint or watchpoint
registers is 16, so the width of 'unsigned long long' is sufficient.
gdb:
2015-07-17 Yao Qi <yao.qi@linaro.org>
* Makefile.in (HFILES_NO_SRCDIR): Add
nat/aarch64-linux-hw-point.h.
(aarch64-linux-hw-point.o): New rule.
* nat/aarch64-linux-hw-point.h: New file.
* nat/aarch64-linux-hw-point.c: New file.
* aarch64-linux-nat.c: Include nat/aarch64-linux-hw-point.h.
(AARCH64_HBP_MAX_NUM): Move to nat/aarch64-linux-hw-point.h.
(AARCH64_HWP_MAX_NUM, AARCH64_HBP_ALIGNMENT): Likewise.
(AARCH64_HWP_ALIGNMENT): Likewise.
(AARCH64_HWP_MAX_LEN_PER_REG): Likewise.
(AARCH64_DEBUG_NUM_SLOTS, AARCH64_DEBUG_ARCH): Likewise.
(AARCH64_DEBUG_ARCH_V8, DR_MARK_ALL_CHANGED): Likewise.
(DR_MARK_N_CHANGED, DR_CLEAR_CHANGED): Likewise.
(DR_HAS_CHANGED, DR_N_HAS_CHANGE): Likewise.
(aarch64_num_bp_regs, aarch64_num_wp_regs): Likewise.
(struct aarch64_debug_reg_state): Likewise.
(struct arch_lwp_info): Likewise.
(aarch64_linux_set_debug_regs): Likewise.
(aarch64_notify_debug_reg_change): Remove static.
(aarch64_align_watchpoint): Likewise.
(DR_CONTROL_ENABLED, DR_CONTROL_LENGTH): Likewise.
(aarch64_watchpoint_length): Likewise.
(aarch64_point_encode_ctrl_reg): Likewise
(aarch64_point_is_aligned): Likewise.
(aarch64_dr_state_insert_one_point): Likewise.
(aarch64_dr_state_remove_one_point): Likewise.
(aarch64_handle_breakpoint): Likewise.
(aarch64_handle_aligned_watchpoint): Likewise.
(aarch64_handle_unaligned_watchpoint): Likewise.
(aarch64_handle_watchpoint): Likewise.
* config/aarch64/linux.mh (NAT_FILE): Add
aarch64-linux-hw-point.o.
gdb/gdbserver:
2015-07-17 Yao Qi <yao.qi@linaro.org>
* Makefile.in (aarch64-linux-hw-point.o): New rule.
* configure.srv (srv_tgtobj): Append aarch64-linux-hw-point.o.
* linux-aarch64-low.c: Include nat/aarch64-linux-hw-point.h.
(AARCH64_HBP_MAX_NUM): Move to nat/aarch64-linux-hw-point.h.
(AARCH64_HWP_MAX_NUM, AARCH64_HBP_ALIGNMENT): Likewise.
(AARCH64_HWP_ALIGNMENT): Likewise.
(AARCH64_HWP_MAX_LEN_PER_REG): Likewise.
(AARCH64_DEBUG_NUM_SLOTS, AARCH64_DEBUG_ARCH): Likewise.
(aarch64_num_bp_regs, aarch64_num_wp_regs): Likewise.
(AARCH64_DEBUG_ARCH_V8, DR_MARK_ALL_CHANGED): Likewise.
(DR_MARK_N_CHANGED, DR_CLEAR_CHANGED): Likewise.
(DR_HAS_CHANGED, DR_N_HAS_CHANGE): Likewise.
(struct aarch64_debug_reg_state): Likewise.
(struct arch_lwp_info): Likewise.
(aarch64_align_watchpoint): Likewise.
(DR_CONTROL_ENABLED, DR_CONTROL_LENGTH): Likewise.
(aarch64_watchpoint_length): Likewise.
(aarch64_point_encode_ctrl_reg): Likewise
(aarch64_point_is_aligned): Likewise.
(aarch64_align_watchpoint): Likewise.
(aarch64_linux_set_debug_regs):
(aarch64_dr_state_insert_one_point): Likewise.
(aarch64_dr_state_remove_one_point): Likewise.
(aarch64_handle_breakpoint): Likewise.
(aarch64_handle_aligned_watchpoint): Likewise.
(aarch64_handle_unaligned_watchpoint): Likewise.
(aarch64_handle_watchpoint): Likewise.
Jan Kratochvil
Joel Brobecker
Yao Qi
Andrew Pinski