This patch is in preparation for software single step support on ARM in
GDBServer. It adds a new shared function regcache_raw_read_unsigned and
regcache_raw_get_unsigned so that GDB and GDBServer can use the same call
to fetch a raw register into an integer.
No regressions, tested on ubuntu 14.04 ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
gdb/ChangeLog:
* Makefile.in (SFILES): Append common/common-regcache.c.
(COMMON_OBS): Append common/common-regcache.o.
(common-regcache.o): New rule.
* common/common-regcache.h (register_status) New enum.
(regcache_raw_read_unsigned): New declaration.
* common/common-regcache.c: New file.
* regcache.h (enum register_status): Move to common-regcache.h.
(regcache_raw_read_unsigned): Likewise.
(regcache_raw_get_unsigned): Likewise.
gdb/gdbserver/ChangeLog:
* Makefile.in (SFILES): Append common/common-regcache.c.
(OBS): Append common-regcache.o.
(common-regcache.o): New rule.
* regcache.c (init_register_cache): Initialize cache to
REG_UNAVAILABLE.
(regcache_raw_read_unsigned): New function.
* regcache.h (REG_UNAVAILABLE, REG_VALID): Replaced by shared
register_status enum.
Nowadays, both aarch64 GDB and linux kernel assumes that address for
setting breakpoint should be 4-byte aligned. However that is not true
after we support multi-arch, because thumb instruction can be at 2-byte
aligned address. Patch http://lists.infradead.org/pipermail/linux-arm-kernel/2015-October/375141.html
to linux kernel is to teach kernel to handle 2-byte aligned address for
HW breakpoint, while this patch is to teach aarch64 GDB handle 2-byte
aligned address.
First of all, we call gdbarch_breakpoint_from_pc to get the instruction
length rather than using hard-coded 4. Secondly, in GDBserver, we set
length back to 2 if it is 3, because GDB encode 3 in it to indicate it
is a 32-bit thumb breakpoint. Then we relax the address alignment
check from 4-byte aligned to 2-byte aligned.
This patch enables some tests (such as gdb.base/break-idempotent.exp,
gdb.base/cond-eval-mode.exp, gdb.base/watchpoint-reuse-slot.exp,) and
fixes many fails (such as gdb.base/hbreak2.exp) when the program is
compiled in thumb mode on aarch64.
Regression tested on aarch64-linux, both native and gdbserver. This
is the last patch of multi-arch work.
gdb:
2015-10-15 Yao Qi <yao.qi@linaro.org>
* aarch64-linux-nat.c (aarch64_linux_insert_hw_breakpoint):
Call gdbarch_breakpoint_from_pc to instruction length.
(aarch64_linux_remove_hw_breakpoint): Likewise.
* common/common-regcache.h (regcache_register_size): Declare.
* nat/aarch64-linux-hw-point.c: Include "common-regcache.h".
(aarch64_point_is_aligned): Set alignment to 2 for breakpoint if
the process is 32bit, otherwise set alignment to 4.
(aarch64_handle_breakpoint): Update comments.
* regcache.c (regcache_register_size): New function.
gdb/gdbserver:
2015-10-15 Yao Qi <yao.qi@linaro.org>
* linux-aarch64-low.c (aarch64_insert_point): Set len to 2
if it is 3.
(aarch64_remove_point): Likewise.
* regcache.c (regcache_register_size): New function.
This introduces common-regcache.h. This contains two functions that
allow nat/linux-btrace.c to be simplified. A better long term
solution would be unify the regcache code, but this is sufficient for
now.
gdb/ChangeLog:
* common/common-regcache.h: New file.
* Makefile.in (HFILES_NO_SRCDIR): Add common/common-regcache.h.
* regcache.h: Include common-regcache.h.
(regcache_read_pc): Don't declare.
* regcache.c (get_thread_regcache_for_ptid): New function.
* nat/linux-btrace.c: Don't include regcache.h.
Include common-regcache.h.
(perf_event_read_bts): Use get_thread_regcache_for_ptid.
gdb/gdbserver/ChangeLog:
* regcache.h: Include common-regcache.h.
(regcache_read_pc): Don't declare.
* regcache.c (get_thread_regcache_for_ptid): New function.
