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Re: [PATCH 3/5] Add support for ARM breakpoint types in GDBServer.
- From: Antoine Tremblay <antoine dot tremblay at ericsson dot com>
- To: Yao Qi <qiyaoltc at gmail dot com>
- Cc: <gdb-patches at sourceware dot org>
- Date: Mon, 28 Sep 2015 17:26:01 -0400
- Subject: Re: [PATCH 3/5] Add support for ARM breakpoint types in GDBServer.
- Authentication-results: sourceware.org; auth=none
- References: <1442577749-6650-1-git-send-email-antoine dot tremblay at ericsson dot com> <1442577749-6650-4-git-send-email-antoine dot tremblay at ericsson dot com> <8637xy96qx dot fsf at gmail dot com>
On 09/28/2015 06:29 AM, Yao Qi wrote:
Antoine Tremblay <antoine.tremblay@ericsson.com> writes:
gdb/ChangeLog:
* Makefile.in: Add arm-common.o.
* arm-tdep.c (thumb_insn_size): Move to arm-common.h/c.
"Move to arm-common.c". Some macros are moved, we should mention the
move here as well.
Done.
* common/arm-common.c: New file.
* common/arm-common.h: New file.
arm-common.c is not a good file name to me, how about arm-insn.c?
This will contain more stuff as I post the next patch sets for single
stepping etc.. I would like to keep a more general name.
It's basically all coming from arm-tdep.c but I don't want to name it
common/arm-tdep.c to avoid confusion and Makefile problems.
arm-ctdep.c ?
Please move this file to arch/ directory rather than common/
It seems weird to me to have common objects somewhere else then in
common/ , if common becomes more a lib we don't want it all over the
place no ?
Would creating a common/arch be acceptable ? I guess we would have to
move things like x86-xstate.h etc.. there too ?
* configure.tgt: Add arm-common.o.
* gdbserver/Makefile.in: Add arm-common.c/o.
ChangeLog entries for GDBserver should be written separately.
Oops my bad sorry about that.
* gdbserver/configure.srv: Add arm-common.o.
* gdbserver/linux-arm-low.c (arm_breakpoint_at): Adjust for
breakpoint types.
(arm_breakpoint_from_pc): New function.
arm_breakpoint_from_pc is not a new function, but arm_is_thumb_mode is.
Done.
diff --git a/gdb/common/arm-common.c b/gdb/common/arm-common.c
new file mode 100644
index 0000000..861b249
--- /dev/null
+++ b/gdb/common/arm-common.c
@@ -0,0 +1,32 @@
+/* Common code for generic ARM support.
+
+ Copyright (C) 2015 Free Software Foundation, Inc.
+
Contents in file are moved from existing file, so we should still keep
the year range of the original file. It should be
Copyright (C) 1988-2015 Free Software Foundation, Inc.
OK np
diff --git a/gdb/configure.tgt b/gdb/configure.tgt
index c42b4df..e831f59 100644
--- a/gdb/configure.tgt
+++ b/gdb/configure.tgt
@@ -89,7 +89,7 @@ arm*-wince-pe | arm*-*-mingw32ce*)
;;
arm*-*-linux*)
# Target: ARM based machine running GNU/Linux
- gdb_target_obs="arm-tdep.o arm-linux-tdep.o glibc-tdep.o \
+ gdb_target_obs="arm-common.o arm-tdep.o arm-linux-tdep.o glibc-tdep.o \
solib-svr4.o symfile-mem.o linux-tdep.o linux-record.o"
build_gdbserver=yes
since arm-common.o is moved out of arm-tdep.o, so it should be added to
every target which uses arm-tdep.o, such as aarch64*-*-linux*,
arm*-wince-pe, etc.
Even if they don't use it ? But ok.
diff --git a/gdb/gdbserver/linux-arm-low.c b/gdb/gdbserver/linux-arm-low.c
index 367c704..15ecb70 100644
--- a/gdb/gdbserver/linux-arm-low.c
+++ b/gdb/gdbserver/linux-arm-low.c
@@ -30,6 +30,8 @@
#include "nat/gdb_ptrace.h"
#include <signal.h>
+#include "common/arm-common.h"
+
/* Defined in auto-generated files. */
void init_registers_arm (void);
extern const struct target_desc *tdesc_arm;
@@ -234,19 +236,28 @@ arm_set_pc (struct regcache *regcache, CORE_ADDR pc)
}
/* Correct in either endianness. */
-static const unsigned long arm_breakpoint = 0xef9f0001;
-#define arm_breakpoint_len 4
-static const unsigned short thumb_breakpoint = 0xde01;
-static const unsigned short thumb2_breakpoint[] = { 0xf7f0, 0xa000 };
+#define arm_abi_breakpoint 0xef9f0001UL
/* For new EABI binaries. We recognize it regardless of which ABI
is used for gdbserver, so single threaded debugging should work
OK, but for multi-threaded debugging we only insert the current
ABI's breakpoint instruction. For now at least. */
-static const unsigned long arm_eabi_breakpoint = 0xe7f001f0;
+#define arm_eabi_breakpoint 0xe7f001f0UL
+
+#ifndef __ARM_EABI__
+static const unsigned long arm_breakpoint = arm_abi_breakpoint;
+#else
+static const unsigned long arm_breakpoint = arm_eabi_breakpoint;
+#endif
+
+#define arm_breakpoint_len 4
+static const unsigned short thumb_breakpoint = 0xde01;
+#define thumb_breakpoint_len 2
+static const unsigned short thumb2_breakpoint[] = { 0xf7f0, 0xa000 };
+#define thumb2_breakpoint_len 4
I am confused by your changes here. Why do you change them?
Before arm_breakpoint_from_pc would be :
#ifndef __ARM_EABI__
return (const unsigned char *) &arm_breakpoint;
#else
- return (const unsigned char *) &arm_eabi_breakpoint;
#endif
And arm_breakpoint_at would check for the arm_breakpoint ||
arm_eabi_breakpoint.
Thus the selected arm_breakpoint would be what that function returned
and arm_breakpoint was arm_abi_breakpoint.
It felt more clear to me to name those for what they are : 2 separate
entities arm_abi_breakpoint and arm_eabi_breakpoint and set the current
used one as arm_breakpoint.
This allows a cleaner breakpoint_from_pc as it just returns
arm_breakpoint rather than having the #ifdef in that function.
Any other reference to the arm_breakpoint would also be clear of #ifdefs...
static int
-arm_breakpoint_at (CORE_ADDR where)
+arm_is_thumb_mode (void)
{
struct regcache *regcache = get_thread_regcache (current_thread, 1);
unsigned long cpsr;
@@ -254,6 +265,17 @@ arm_breakpoint_at (CORE_ADDR where)
collect_register_by_name (regcache, "cpsr", &cpsr);
if (cpsr & 0x20)
+ return 1;
+ else
+ return 0;
Indentation looks odd.
Done.
+}
+
+/* Returns 1 if there is a software breakpoint at location. */
+
+static int
+arm_breakpoint_at (CORE_ADDR where)
+{
+ if (arm_is_thumb_mode ())
{
/* Thumb mode. */
unsigned short insn;
@@ -275,7 +297,7 @@ arm_breakpoint_at (CORE_ADDR where)
unsigned long insn;
(*the_target->read_memory) (where, (unsigned char *) &insn, 4);
- if (insn == arm_breakpoint)
+ if (insn == arm_abi_breakpoint)
return 1;
if (insn == arm_eabi_breakpoint)
@@ -285,6 +307,53 @@ arm_breakpoint_at (CORE_ADDR where)
return 0;
}
+/* Determine the type and size of breakpoint to insert at PCPTR. Uses
+ the program counter value to determine whether a 16-bit or 32-bit
+ breakpoint should be used. It returns a pointer to a string of
+ bytes that encode a breakpoint instruction, stores the length of
+ the string to *lenptr, and adjusts the program counter (if
+ necessary) to point to the actual memory location where the
+ breakpoint should be inserted. */
+
+static const unsigned char *
+arm_breakpoint_from_pc (CORE_ADDR *pcptr, int *lenptr)
+{
+ /* Default if no pc is set to arm breakpoint. */
+ if (pcptr == NULL)
Such NULL checking is no longer needed, right?
Indeed this is gone based on comments in patch 1/5.