aarch64: Add an aarch64_nat_target mixin class.

This class includes platform-independent target methods for hardware
breakpoints and watchpoints using routines from
nat/aarch64-hw-point.c.

stopped_data_address is not platform-independent since the FAR
register holding the address for a breakpoint hit must be fetched in a
platform-specific manner.  However, aarch64_stopped_data_address is
provided as a helper routine which performs platform-independent
validation given the value of the FAR register.

For tracking the per-process debug register mirror state, use an
unordered_map indexed by pid as recently adopted in x86-nat.c rather
than a manual linked-list.

1 files changed, 109 insertions, 0 deletions

diff --git a/gdb/aarch64-nat.h b/gdb/aarch64-nat.h
new file mode 100644
index 0000000..56e720f
--- /dev/null
+++ b/gdb/aarch64-nat.h
@@ -0,0 +1,109 @@
+/* Native-dependent code for AArch64.
+
+   Copyright (C) 2011-2022 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef AARCH64_NAT_H
+#define AARCH64_NAT_H
+
+#include "breakpoint.h"
+#include "nat/aarch64-hw-point.h"
+#include "target.h"
+
+/* Hardware-assisted breakpoints and watchpoints.  */
+
+/* Initialize platform-independent state for hardware-assisted
+   breakpoints and watchpoints.  */
+
+void aarch64_initialize_hw_point ();
+
+/* Return the debug register state for process PID.  If no existing
+   state is found for this process, return nullptr.  */
+
+struct aarch64_debug_reg_state *aarch64_lookup_debug_reg_state (pid_t pid);
+
+/* Return the debug register state for process PID.  If no existing
+   state is found for this process, create new state.  */
+
+struct aarch64_debug_reg_state *aarch64_get_debug_reg_state (pid_t pid);
+
+/* Remove any existing per-process debug state for process PID.  */
+
+void aarch64_remove_debug_reg_state (pid_t pid);
+
+/* Helper for the "stopped_data_address" target method.  Returns TRUE
+   if a hardware watchpoint trap at ADDR_TRAP matches a set
+   watchpoint.  The address of the matched watchpoint is returned in
+   *ADDR_P.  */
+
+bool aarch64_stopped_data_address (const struct aarch64_debug_reg_state *state,
+				   CORE_ADDR addr_trap, CORE_ADDR *addr_p);
+
+/* Helper functions used by aarch64_nat_target below.  See their
+   definitions.  */
+
+int aarch64_can_use_hw_breakpoint (enum bptype type, int cnt, int othertype);
+int aarch64_insert_watchpoint (CORE_ADDR addr, int len,
+			       enum target_hw_bp_type type,
+			       struct expression *cond);
+int aarch64_remove_watchpoint (CORE_ADDR addr, int len,
+			       enum target_hw_bp_type type,
+			       struct expression *cond);
+int aarch64_insert_hw_breakpoint (struct gdbarch *gdbarch,
+				  struct bp_target_info *bp_tgt);
+int aarch64_remove_hw_breakpoint (struct gdbarch *gdbarch,
+				  struct bp_target_info *bp_tgt);
+int aarch64_stopped_by_hw_breakpoint ();
+
+/* Convenience template mixin used to add aarch64 watchpoints support to a
+   target.  */
+
+template <typename BaseTarget>
+struct aarch64_nat_target : public BaseTarget
+{
+  /* Hook in common aarch64 hardware watchpoints/breakpoints support.  */
+
+  int can_use_hw_breakpoint (enum bptype type, int cnt, int othertype) override
+  { return aarch64_can_use_hw_breakpoint (type, cnt, othertype); }
+
+  int region_ok_for_hw_watchpoint (CORE_ADDR addr, int len) override
+  { return aarch64_region_ok_for_watchpoint (addr, len); }
+
+  int insert_watchpoint (CORE_ADDR addr, int len,
+			 enum target_hw_bp_type type,
+			 struct expression *cond) override
+  { return aarch64_insert_watchpoint (addr, len, type, cond); }
+
+  int remove_watchpoint (CORE_ADDR addr, int len,
+			 enum target_hw_bp_type type,
+			 struct expression *cond) override
+  { return aarch64_remove_watchpoint (addr, len, type, cond); }
+
+  int insert_hw_breakpoint (struct gdbarch *gdbarch,
+			    struct bp_target_info *bp_tgt) override
+  { return aarch64_insert_hw_breakpoint (gdbarch, bp_tgt); }
+
+  int remove_hw_breakpoint (struct gdbarch *gdbarch,
+			    struct bp_target_info *bp_tgt) override
+  { return aarch64_remove_hw_breakpoint (gdbarch, bp_tgt); }
+
+  bool watchpoint_addr_within_range (CORE_ADDR addr, CORE_ADDR start,
+				     int length) override
+  { return start <= addr && start + length - 1 >= addr; }
+};
+
+#endif /* AARCH64_NAT_H */