[PATCHv3,Hurd] Add hardware watch support

Samuel Thibault
2014-09-10T22:49:34Z

2014-09-06 Samuel Thibault <samuel.thibault@ens-lyon.org>

Add hardware watch support to gnu-i386 platform.

* gdb/gdb/gnu-nat.c (inf_threads): New function.
* gdb/gdb/gnu-nat.h (inf_threads_ftype): New type.
(inf_threads): New declaration.
* gdb/gdb/i386gnu-nat.c: Include "x86-nat.h" and "inf-child.h".
[i386_DEBUG_STATE] (i386_gnu_dr_get, i386_gnu_dr_set,
i386_gnu_dr_set_control_one, i386_gnu_dr_set_control,
i386_gnu_dr_set_addr_one, i386_gnu_dr_set_addr, i386_gnu_dr_get_reg,
i386_gnu_dr_get_addr, 386_gnu_dr_get_status, i386_gnu_dr_get_control):
New functions
(reg_addr): New structure.
(_initialize_i386gnu_nat) [i386_DEBUG_STATE]: Initialize hardware i386
debugging register hooks.

diff --git a/gdb/gnu-nat.c b/gdb/gnu-nat.c
index c8164d6..2d7c32c 100644
--- a/gdb/gnu-nat.c
+++ b/gdb/gnu-nat.c
@@ -983,6 +983,16 @@ inf_port_to_thread (struct inf *inf, mach_port_t port)
return 0;
}

+/* Iterate F over threads. */
+void
+inf_threads (struct inf *inf, inf_threads_ftype *f)
+{
+ struct proc *thread;
+
+ for (thread = inf->threads; thread; thread = thread->next)
+ f (thread);
+}
+
\f
/* Make INF's list of threads be consistent with reality of TASK. */
void
diff --git a/gdb/gnu-nat.h b/gdb/gnu-nat.h
index 8e949eb..011c38c 100644
--- a/gdb/gnu-nat.h
+++ b/gdb/gnu-nat.h
@@ -29,6 +29,11 @@ extern struct inf *gnu_current_inf;
/* Converts a GDB pid to a struct proc. */
struct proc *inf_tid_to_thread (struct inf *inf, int tid);

+typedef void (inf_threads_ftype) (struct proc *thread);
+
+/* Iterate F over threads. */
+void inf_threads (struct inf *inf, inf_threads_ftype *f);
+
/* Makes sure that INF's thread list is synced with the actual process. */
int inf_update_procs (struct inf *inf);

diff --git a/gdb/i386gnu-nat.c b/gdb/i386gnu-nat.c
index 8fad871..5654e9a 100644
--- a/gdb/i386gnu-nat.c
+++ b/gdb/i386gnu-nat.c
@@ -18,6 +18,7 @@
along with this program. If not, see <http://www.gnu.org/licenses/>. */

#include "defs.h"
+#include "x86-nat.h"
#include "inferior.h"
#include "floatformat.h"
#include "regcache.h"
@@ -30,6 +31,7 @@
#include "i386-tdep.h"

#include "gnu-nat.h"
+#include "inf-child.h"
#include "i387-tdep.h"

#ifdef HAVE_SYS_PROCFS_H
@@ -304,6 +306,130 @@ gnu_store_registers (struct target_ops *ops,
}
}

+\f
+/* Support for debug registers. */
+
+#ifdef i386_DEBUG_STATE
+/* Get debug registers for thread THREAD. */
+
+static void
+i386_gnu_dr_get (struct i386_debug_state *regs, struct proc *thread)
+{
+ mach_msg_type_number_t count = i386_DEBUG_STATE_COUNT;
+ error_t err;
+
+ err = thread_get_state (thread->port, i386_DEBUG_STATE,
+ (thread_state_t) regs, &count);
+ if (err != 0 || count != i386_DEBUG_STATE_COUNT)
+ warning (_("Couldn't fetch debug state from %s"),
+ proc_string (thread));
+}
+
+/* Set debug registers for thread THREAD. */
+
+static void
+i386_gnu_dr_set (const struct i386_debug_state *regs, struct proc *thread)
+{
+ error_t err;
+
+ err = thread_set_state (thread->port, i386_DEBUG_STATE,
+ (thread_state_t) regs, i386_DEBUG_STATE_COUNT);
+ if (err != 0)
+ warning (_("Couldn't store debug state into %s"),
+ proc_string (thread));
+}
+
+static void i386_gnu_dr_set_control_one (struct proc *thread, void *arg)
+{
+ unsigned long *control = arg;
+ struct i386_debug_state regs;
+ i386_gnu_dr_get (&regs, thread);
+ regs.dr[DR_CONTROL] = *control;
+ i386_gnu_dr_set (&regs, thread);
+}
+
+/* Set DR_CONTROL to CONTROL in all threads. */
+
+static void
+i386_gnu_dr_set_control (unsigned long control)
+{
+ inf_update_procs (gnu_current_inf);
+ inf_threads (gnu_current_inf, i386_gnu_dr_set_control_one, &control);
+}
+
+struct reg_addr {
+ int regnum;
+ CORE_ADDR addr;
+};
+
+static void i386_gnu_dr_set_addr_one (struct proc *thread, void *arg)
+{
+ struct reg_addr *reg_addr = arg;
+ struct i386_debug_state regs;
+ i386_gnu_dr_get (&regs, thread);
+ regs.dr[reg_addr->regnum] = reg_addr->addr;
+ i386_gnu_dr_set (&regs, thread);
+}
+
+/* Set address REGNUM (zero based) to ADDR in all threads. */
+
+static void
+i386_gnu_dr_set_addr (int regnum, CORE_ADDR addr)
+{
+ struct reg_addr reg_addr;
+ gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
+
+ reg_addr.regnum = regnum;
+ reg_addr.addr = addr;
+
+ inf_update_procs (gnu_current_inf);
+ inf_threads (gnu_current_inf, i386_gnu_dr_set_addr_one, &reg_addr);
+}
+
+/* Get debug register REGNUM value from only the one LWP of PTID. */
+
+static unsigned long
+i386_gnu_dr_get_reg (ptid_t ptid, int regnum)
+{
+ struct i386_debug_state regs;
+ struct proc *thread;
+
+ /* Make sure we know about new threads. */
+ inf_update_procs (gnu_current_inf);
+
+ thread = inf_tid_to_thread (gnu_current_inf, ptid_get_lwp (ptid));
+ i386_gnu_dr_get (&regs, thread);
+
+ return regs.dr[regnum];
+}
+
+/* Return the inferior's debug register REGNUM. */
+
+static CORE_ADDR
+i386_gnu_dr_get_addr (int regnum)
+{
+ gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
+
+ return i386_gnu_dr_get_reg (inferior_ptid, regnum);
+}
+
+/* Get DR_STATUS from only the one thread of INFERIOR_PTID. */
+
+static unsigned long
+i386_gnu_dr_get_status (void)
+{
+ return i386_gnu_dr_get_reg (inferior_ptid, DR_STATUS);
+}
+
+/* Return the inferior's DR7 debug control register. */
+
+static unsigned long
+i386_gnu_dr_get_control (void)
+{
+ return i386_gnu_dr_get_reg (inferior_ptid, DR_CONTROL);
+}
+#endif /* i386_DEBUG_STATE */
+
/* Provide a prototype to silence -Wmissing-prototypes. */
extern initialize_file_ftype _initialize_i386gnu_nat;

@@ -315,6 +430,18 @@ _initialize_i386gnu_nat (void)
/* Fill in the generic GNU/Hurd methods. */
t = gnu_target ();

+#ifdef i386_DEBUG_STATE
+ x86_use_watchpoints (t);
+
+ x86_dr_low.set_control = i386_gnu_dr_set_control;
+ gdb_assert (DR_FIRSTADDR == 0 && DR_LASTADDR < i386_DEBUG_STATE_COUNT);
+ x86_dr_low.set_addr = i386_gnu_dr_set_addr;
+ x86_dr_low.get_addr = i386_gnu_dr_get_addr;
+ x86_dr_low.get_status = i386_gnu_dr_get_status;
+ x86_dr_low.get_control = i386_gnu_dr_get_control;
+ x86_set_debug_register_length (4);
+#endif /* i386_DEBUG_STATE */
+
t->to_fetch_registers = gnu_fetch_registers;
t->to_store_registers = gnu_store_registers;

diff --git a/gdb/config/i386/i386gnu.mh b/gdb/config/i386/i386gnu.mh
index a3ea122..9d76b59 100644
--- a/gdb/config/i386/i386gnu.mh
+++ b/gdb/config/i386/i386gnu.mh
@@ -1,5 +1,5 @@
# Host: Intel 386 running the GNU Hurd
-NATDEPFILES= i386gnu-nat.o gnu-nat.o core-regset.o fork-child.o \
+NATDEPFILES= i386gnu-nat.o gnu-nat.o x86-nat.o core-regset.o fork-child.o \
notify_S.o process_reply_S.o msg_reply_S.o \
msg_U.o exc_request_U.o exc_request_S.o
HAVE_NATIVE_GCORE_HOST = 1