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authorAntoine Tremblay <antoine.tremblay@ericsson.com>2015-11-30 15:08:04 -0500
committerAntoine Tremblay <antoine.tremblay@ericsson.com>2015-11-30 15:08:04 -0500
commit769ef81fec526f3c7513c88e82f98045f8971d14 (patch)
tree3c540206c97b423611558c38efbae5e4dcd35278 /gdb
parentfddedbe665db9cb9824150e454c89abdc750957a (diff)
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Fix breakpoint size when stepping over a permanent breakpoint in GDBServer.
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.
Diffstat (limited to 'gdb')
-rw-r--r--gdb/gdbserver/ChangeLog15
-rw-r--r--gdb/gdbserver/linux-arm-low.c40
-rw-r--r--gdb/gdbserver/linux-low.c16
-rw-r--r--gdb/gdbserver/linux-low.h3
-rw-r--r--gdb/gdbserver/target.h11
5 files changed, 83 insertions, 2 deletions
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 6330c03..87ce9e7 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,18 @@
+2015-11-30 Antoine Tremblay <antoine.tremblay@ericsson.com>
+
+ * 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.
+
2015-11-30 Pedro Alves <palves@redhat.com>
* linux-low.c (linux_resume): Wake up the event loop before
diff --git a/gdb/gdbserver/linux-arm-low.c b/gdb/gdbserver/linux-arm-low.c
index dda37cb..6f37f58 100644
--- a/gdb/gdbserver/linux-arm-low.c
+++ b/gdb/gdbserver/linux-arm-low.c
@@ -264,8 +264,10 @@ static const unsigned short thumb_breakpoint = 0xde01;
static const unsigned short thumb2_breakpoint[] = { 0xf7f0, 0xa000 };
#define thumb2_breakpoint_len 4
+/* Returns 1 if the current instruction set is thumb, 0 otherwise. */
+
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;
@@ -273,6 +275,17 @@ arm_breakpoint_at (CORE_ADDR where)
collect_register_by_name (regcache, "cpsr", &cpsr);
if (cpsr & 0x20)
+ return 1;
+ else
+ return 0;
+}
+
+/* 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;
@@ -996,6 +1009,23 @@ arm_sw_breakpoint_from_kind (int kind , int *size)
return NULL;
}
+/* Implementation of the linux_target_ops method
+ "breakpoint_kind_from_current_state". */
+
+static int
+arm_breakpoint_kind_from_current_state (CORE_ADDR *pcptr)
+{
+ if (arm_is_thumb_mode ())
+ {
+ *pcptr = MAKE_THUMB_ADDR (*pcptr);
+ return arm_breakpoint_kind_from_pc (pcptr);
+ }
+ else
+ {
+ return arm_breakpoint_kind_from_pc (pcptr);
+ }
+}
+
struct linux_target_ops the_low_target = {
arm_arch_setup,
arm_regs_info,
@@ -1021,6 +1051,14 @@ struct linux_target_ops the_low_target = {
arm_new_thread,
arm_new_fork,
arm_prepare_to_resume,
+ NULL, /* process_qsupported */
+ NULL, /* supports_tracepoints */
+ NULL, /* get_thread_area */
+ NULL, /* install_fast_tracepoint_jump_pad */
+ NULL, /* emit_ops */
+ NULL, /* get_min_fast_tracepoint_insn_len */
+ NULL, /* supports_range_stepping */
+ arm_breakpoint_kind_from_current_state
};
void
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 086b202..207a5ba 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -3084,7 +3084,8 @@ linux_wait_1 (ptid_t ptid,
int breakpoint_kind = 0;
CORE_ADDR stop_pc = event_child->stop_pc;
- breakpoint_kind = the_target->breakpoint_kind_from_pc (&stop_pc);
+ breakpoint_kind =
+ the_target->breakpoint_kind_from_current_state (&stop_pc);
the_target->sw_breakpoint_from_kind (breakpoint_kind, &increment_pc);
if (debug_threads)
@@ -7036,6 +7037,18 @@ linux_sw_breakpoint_from_kind (int kind, int *size)
return (*the_low_target.sw_breakpoint_from_kind) (kind, size);
}
+/* Implementation of the target_ops method
+ "breakpoint_kind_from_current_state". */
+
+static int
+linux_breakpoint_kind_from_current_state (CORE_ADDR *pcptr)
+{
+ if (the_low_target.breakpoint_kind_from_current_state != NULL)
+ return (*the_low_target.breakpoint_kind_from_current_state) (pcptr);
+ else
+ return linux_breakpoint_kind_from_pc (pcptr);
+}
+
static struct target_ops linux_target_ops = {
linux_create_inferior,
linux_arch_setup,
@@ -7133,6 +7146,7 @@ static struct target_ops linux_target_ops = {
linux_breakpoint_kind_from_pc,
linux_sw_breakpoint_from_kind,
linux_proc_tid_get_name,
+ linux_breakpoint_kind_from_current_state
};
static void
diff --git a/gdb/gdbserver/linux-low.h b/gdb/gdbserver/linux-low.h
index f1d4f0f..e2bfeb7 100644
--- a/gdb/gdbserver/linux-low.h
+++ b/gdb/gdbserver/linux-low.h
@@ -233,6 +233,9 @@ struct linux_target_ops
/* Returns true if the low target supports range stepping. */
int (*supports_range_stepping) (void);
+
+ /* See target.h. */
+ int (*breakpoint_kind_from_current_state) (CORE_ADDR *pcptr);
};
extern struct linux_target_ops the_low_target;
diff --git a/gdb/gdbserver/target.h b/gdb/gdbserver/target.h
index a09ba2f..d3fcb36 100644
--- a/gdb/gdbserver/target.h
+++ b/gdb/gdbserver/target.h
@@ -457,6 +457,12 @@ struct target_ops
/* Return the thread's name, or NULL if the target is unable to determine it.
The returned value must not be freed by the caller. */
const char *(*thread_name) (ptid_t thread);
+
+ /* Return the breakpoint kind for this target based on the current
+ processor state (e.g. the current instruction mode on ARM) and the
+ PC. The PCPTR is adjusted to the real memory location in case a flag
+ (e.g., the Thumb bit on ARM) is present in the PC. */
+ int (*breakpoint_kind_from_current_state) (CORE_ADDR *pcptr);
};
extern struct target_ops *the_target;
@@ -644,6 +650,11 @@ int kill_inferior (int);
? (*the_target->breakpoint_kind_from_pc) (pcptr) \
: default_breakpoint_kind_from_pc (pcptr))
+#define target_breakpoint_kind_from_current_state(pcptr) \
+ (the_target->breakpoint_kind_from_current_state \
+ ? (*the_target->breakpoint_kind_from_current_state) (pcptr) \
+ : target_breakpoint_kind_from_pc (pcptr))
+
/* Start non-stop mode, returns 0 on success, -1 on failure. */
int start_non_stop (int nonstop);