[PATCH v2 2/4] build: use common stubs for debugger_trap_* functions if !CONFIG_CRASH_DEBUG

[Bobby Eshleman <bobby.eshleman@gmail.com>]

Previously Xen required all architectures implement the debugger_trap_*
functions whether or not it actually needs them.

This commit makes debugger_trap* functions resolve to arch-specific
function definitions if CONFIG_CRASH_DEBUG=y, but resolves to a set of
common no-op stubs if !CONFIG_CRASH_DEBUG, which avoids requiring every
arch to carry its own stubs.  This means asm/debugger.h may also be
dropped for architectures that do not need this functionality.

Inside xen/debugger.h:
    * If !CONFIG_CRASH_DEBUG, use stubs.
    * Otherwise, include arch-specific <asm/debugger.h>
---

Changes in v2:
- #include ordering (xen/.h before asm/.h, alphabetical order)
- Other style (no double blanks in comments).
- Removed dummy TRAP_invalid_op for ARM (not needed because
  the patch to remove the calls is now prior to this patch)
- Removed common-izing of dbg_rw_mem

 xen/arch/arm/traps.c            |  2 +-
 xen/arch/x86/debug.c            |  2 +-
 xen/arch/x86/domain.c           |  5 ++-
 xen/arch/x86/domctl.c           |  2 +-
 xen/arch/x86/gdbstub.c          |  4 +-
 xen/arch/x86/hvm/svm/svm.c      |  2 +-
 xen/arch/x86/hvm/vmx/realmode.c |  2 +-
 xen/arch/x86/hvm/vmx/vmx.c      |  2 +-
 xen/arch/x86/nmi.c              |  2 +-
 xen/arch/x86/traps.c            |  2 +-
 xen/arch/x86/x86_64/gdbstub.c   |  3 +-
 xen/common/domain.c             |  2 +-
 xen/common/gdbstub.c            |  3 +-
 xen/common/keyhandler.c         |  2 +-
 xen/common/shutdown.c           |  2 +-
 xen/drivers/char/console.c      |  2 +-
 xen/include/asm-arm/debugger.h  | 15 -------
 xen/include/asm-x86/debugger.h  | 60 ++++++----------------------
 xen/include/xen/debugger.h      | 69 +++++++++++++++++++++++++++++++++
 19 files changed, 103 insertions(+), 80 deletions(-)
 delete mode 100644 xen/include/asm-arm/debugger.h
 create mode 100644 xen/include/xen/debugger.h

diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index dd09d2a4a9..10db98e01a 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -16,6 +16,7 @@
  * GNU General Public License for more details.
  */
 
+#include <xen/debugger.h>
 #include <xen/domain_page.h>
 #include <xen/errno.h>
 #include <xen/hypercall.h>
@@ -41,7 +42,6 @@
 #include <asm/acpi.h>
 #include <asm/cpuerrata.h>
 #include <asm/cpufeature.h>
-#include <asm/debugger.h>
 #include <asm/event.h>
 #include <asm/hsr.h>
 #include <asm/mmio.h>
diff --git a/xen/arch/x86/debug.c b/xen/arch/x86/debug.c
index d90dc93056..583a9a042a 100644
--- a/xen/arch/x86/debug.c
+++ b/xen/arch/x86/debug.c
@@ -14,12 +14,12 @@
  * License along with this program; If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <xen/debugger.h>
 #include <xen/sched.h>
 #include <xen/compile.h>
 #include <xen/mm.h>
 #include <xen/domain_page.h>
 #include <xen/guest_access.h>
-#include <asm/debugger.h>
 #include <asm/p2m.h>
 
 typedef unsigned long dbgva_t;
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index ef1812dc14..5b948ff270 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -15,6 +15,7 @@
 #include <xen/lib.h>
 #include <xen/errno.h>
 #include <xen/sched.h>
+#include <xen/debugger.h>
 #include <xen/domain.h>
 #include <xen/smp.h>
 #include <xen/delay.h>
@@ -2539,9 +2540,9 @@ static int __init init_vcpu_kick_softirq(void)
 }
 __initcall(init_vcpu_kick_softirq);
 
+#ifdef CONFIG_CRASH_DEBUG
 void domain_pause_for_debugger(void)
 {
-#ifdef CONFIG_CRASH_DEBUG
     struct vcpu *curr = current;
     struct domain *d = curr->domain;
 
@@ -2550,8 +2551,8 @@ void domain_pause_for_debugger(void)
     /* if gdbsx active, we just need to pause the domain */
     if ( curr->arch.gdbsx_vcpu_event == 0 )
         send_global_virq(VIRQ_DEBUGGER);
-#endif
 }
+#endif
 
 /*
  * Local variables:
diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index 26a76d2be9..24bdb86de7 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -12,6 +12,7 @@
 #include <xen/pci.h>
 #include <public/domctl.h>
 #include <xen/sched.h>
+#include <xen/debugger.h>
 #include <xen/domain.h>
 #include <xen/event.h>
 #include <xen/domain_page.h>
@@ -33,7 +34,6 @@
 #include <public/vm_event.h>
 #include <asm/mem_sharing.h>
 #include <asm/xstate.h>
-#include <asm/debugger.h>
 #include <asm/psr.h>
 #include <asm/cpuid.h>
 
diff --git a/xen/arch/x86/gdbstub.c b/xen/arch/x86/gdbstub.c
index 8f4f49fd3b..5e23d27f62 100644
--- a/xen/arch/x86/gdbstub.c
+++ b/xen/arch/x86/gdbstub.c
@@ -18,7 +18,9 @@
  * You should have received a copy of the GNU General Public License
  * along with this program; If not, see <http://www.gnu.org/licenses/>.
  */
-#include <asm/debugger.h>
+#include <xen/debugger.h>
+#include <xen/gdbstub.h>
+#include <asm/uaccess.h>
 
 u16
 gdb_arch_signal_num(struct cpu_user_regs *regs, unsigned long cookie)
diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index 642a64b747..ce1cbe7825 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -24,6 +24,7 @@
 #include <xen/irq.h>
 #include <xen/softirq.h>
 #include <xen/hypercall.h>
+#include <xen/debugger.h>
 #include <xen/domain_page.h>
 #include <xen/xenoprof.h>
 #include <asm/current.h>
@@ -58,7 +59,6 @@
 #include <asm/hvm/trace.h>
 #include <asm/hap.h>
 #include <asm/apic.h>
-#include <asm/debugger.h>
 #include <asm/hvm/monitor.h>
 #include <asm/monitor.h>
 #include <asm/xstate.h>
diff --git a/xen/arch/x86/hvm/vmx/realmode.c b/xen/arch/x86/hvm/vmx/realmode.c
index cc23afa788..57d230c4fe 100644
--- a/xen/arch/x86/hvm/vmx/realmode.c
+++ b/xen/arch/x86/hvm/vmx/realmode.c
@@ -9,12 +9,12 @@
  *    Keir Fraser <keir@xen.org>
  */
 
+#include <xen/debugger.h>
 #include <xen/init.h>
 #include <xen/lib.h>
 #include <xen/sched.h>
 #include <xen/paging.h>
 #include <xen/softirq.h>
-#include <asm/debugger.h>
 #include <asm/event.h>
 #include <asm/hvm/emulate.h>
 #include <asm/hvm/hvm.h>
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index e09b7e3af9..00107e8a3b 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -23,6 +23,7 @@
 #include <xen/sched.h>
 #include <xen/irq.h>
 #include <xen/softirq.h>
+#include <xen/debugger.h>
 #include <xen/domain_page.h>
 #include <xen/hypercall.h>
 #include <xen/perfc.h>
@@ -51,7 +52,6 @@
 #include <asm/hvm/trace.h>
 #include <asm/hvm/monitor.h>
 #include <asm/xenoprof.h>
-#include <asm/debugger.h>
 #include <asm/apic.h>
 #include <asm/hvm/nestedhvm.h>
 #include <asm/altp2m.h>
diff --git a/xen/arch/x86/nmi.c b/xen/arch/x86/nmi.c
index ab94a96c4d..505358b656 100644
--- a/xen/arch/x86/nmi.c
+++ b/xen/arch/x86/nmi.c
@@ -18,6 +18,7 @@
 #include <xen/mm.h>
 #include <xen/param.h>
 #include <xen/irq.h>
+#include <xen/debugger.h>
 #include <xen/delay.h>
 #include <xen/time.h>
 #include <xen/sched.h>
@@ -30,7 +31,6 @@
 #include <asm/msr.h>
 #include <asm/mpspec.h>
 #include <asm/nmi.h>
-#include <asm/debugger.h>
 #include <asm/div64.h>
 #include <asm/apic.h>
 
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index e60af16ddd..8561ffe3fe 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -27,6 +27,7 @@
 #include <xen/init.h>
 #include <xen/sched.h>
 #include <xen/lib.h>
+#include <xen/debugger.h>
 #include <xen/err.h>
 #include <xen/errno.h>
 #include <xen/mm.h>
@@ -62,7 +63,6 @@
 #include <asm/uaccess.h>
 #include <asm/i387.h>
 #include <asm/xstate.h>
-#include <asm/debugger.h>
 #include <asm/msr.h>
 #include <asm/nmi.h>
 #include <asm/xenoprof.h>
diff --git a/xen/arch/x86/x86_64/gdbstub.c b/xen/arch/x86/x86_64/gdbstub.c
index 2626519c89..126af03f50 100644
--- a/xen/arch/x86/x86_64/gdbstub.c
+++ b/xen/arch/x86/x86_64/gdbstub.c
@@ -17,7 +17,8 @@
  * along with this program; If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <asm/debugger.h>
+#include <xen/debugger.h>
+#include <xen/gdbstub.h>
 
 #define GDB_REG64(r) gdb_write_to_packet_hex(r, sizeof(u64), ctx)
 #define GDB_REG32(r)  gdb_write_to_packet_hex(r, sizeof(u32), ctx)
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 6b71c6d6a9..a87d814b38 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -11,6 +11,7 @@
 #include <xen/err.h>
 #include <xen/param.h>
 #include <xen/sched.h>
+#include <xen/debugger.h>
 #include <xen/domain.h>
 #include <xen/mm.h>
 #include <xen/event.h>
@@ -33,7 +34,6 @@
 #include <xen/xenoprof.h>
 #include <xen/irq.h>
 #include <xen/argo.h>
-#include <asm/debugger.h>
 #include <asm/p2m.h>
 #include <asm/processor.h>
 #include <public/sched.h>
diff --git a/xen/common/gdbstub.c b/xen/common/gdbstub.c
index 848c1f4327..c233eb2b49 100644
--- a/xen/common/gdbstub.c
+++ b/xen/common/gdbstub.c
@@ -38,12 +38,13 @@
 #include <xen/serial.h>
 #include <xen/irq.h>
 #include <xen/watchdog.h>
-#include <asm/debugger.h>
 #include <xen/init.h>
 #include <xen/param.h>
 #include <xen/smp.h>
 #include <xen/console.h>
 #include <xen/errno.h>
+#include <xen/gdbstub.h>
+#include <xen/debugger.h>
 #include <xen/delay.h>
 #include <asm/byteorder.h>
 
diff --git a/xen/common/keyhandler.c b/xen/common/keyhandler.c
index 8b9f378371..1eafaef9b2 100644
--- a/xen/common/keyhandler.c
+++ b/xen/common/keyhandler.c
@@ -3,6 +3,7 @@
  */
 
 #include <asm/regs.h>
+#include <xen/debugger.h>
 #include <xen/delay.h>
 #include <xen/keyhandler.h>
 #include <xen/param.h>
@@ -20,7 +21,6 @@
 #include <xen/mm.h>
 #include <xen/watchdog.h>
 #include <xen/init.h>
-#include <asm/debugger.h>
 #include <asm/div64.h>
 
 static unsigned char keypress_key;
diff --git a/xen/common/shutdown.c b/xen/common/shutdown.c
index abde48aa4c..f51d44fdc4 100644
--- a/xen/common/shutdown.c
+++ b/xen/common/shutdown.c
@@ -1,3 +1,4 @@
+#include <xen/debugger.h>
 #include <xen/init.h>
 #include <xen/lib.h>
 #include <xen/param.h>
@@ -8,7 +9,6 @@
 #include <xen/shutdown.h>
 #include <xen/console.h>
 #include <xen/kexec.h>
-#include <asm/debugger.h>
 #include <public/sched.h>
 
 /* opt_noreboot: If true, machine will need manual reset on error. */
diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index 7d0a603d03..3d1cdde821 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -15,6 +15,7 @@
 #include <xen/init.h>
 #include <xen/event.h>
 #include <xen/console.h>
+#include <xen/debugger.h>
 #include <xen/param.h>
 #include <xen/serial.h>
 #include <xen/softirq.h>
@@ -26,7 +27,6 @@
 #include <xen/kexec.h>
 #include <xen/ctype.h>
 #include <xen/warning.h>
-#include <asm/debugger.h>
 #include <asm/div64.h>
 #include <xen/hypercall.h> /* for do_console_io */
 #include <xen/early_printk.h>
diff --git a/xen/include/asm-arm/debugger.h b/xen/include/asm-arm/debugger.h
deleted file mode 100644
index ac776efa78..0000000000
--- a/xen/include/asm-arm/debugger.h
+++ /dev/null
@@ -1,15 +0,0 @@
-#ifndef __ARM_DEBUGGER_H__
-#define __ARM_DEBUGGER_H__
-
-#define debugger_trap_fatal(v, r) (0)
-#define debugger_trap_immediate() ((void) 0)
-
-#endif /* __ARM_DEBUGGER_H__ */
-/*
- * Local variables:
- * mode: C
- * c-file-style: "BSD"
- * c-basic-offset: 4
- * indent-tabs-mode: nil
- * End:
- */
diff --git a/xen/include/asm-x86/debugger.h b/xen/include/asm-x86/debugger.h
index 99803bfd0c..c856c1b795 100644
--- a/xen/include/asm-x86/debugger.h
+++ b/xen/include/asm-x86/debugger.h
@@ -1,44 +1,26 @@
 /******************************************************************************
- * asm/debugger.h
- * 
- * Generic hooks into arch-dependent Xen.
- * 
- * Each debugger should define two functions here:
- * 
- * 1. debugger_trap_entry(): 
- *  Called at start of any synchronous fault or trap, before any other work
- *  is done. The idea is that if your debugger deliberately caused the trap
- *  (e.g. to implement breakpoints or data watchpoints) then you can take
- *  appropriate action and return a non-zero value to cause early exit from
- *  the trap function.
- * 
- * 2. debugger_trap_fatal():
- *  Called when Xen is about to give up and crash. Typically you will use this
- *  hook to drop into a debug session. It can also be used to hook off
- *  deliberately caused traps (which you then handle and return non-zero).
+ * x86 Debugger Hooks
  *
- * 3. debugger_trap_immediate():
- *  Called if we want to drop into a debugger now.  This is essentially the
- *  same as debugger_trap_fatal, except that we use the current register state
- *  rather than the state which was in effect when we took the trap.
- *  For example: if we're dying because of an unhandled exception, we call
- *  debugger_trap_fatal; if we're dying because of a panic() we call
- *  debugger_trap_immediate().
+ * 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 __X86_DEBUGGER_H__
 #define __X86_DEBUGGER_H__
 
+#include <xen/domain.h>
+#include <xen/event.h>
+#include <xen/gdbstub.h>
 #include <xen/sched.h>
 #include <asm/regs.h>
 #include <asm/processor.h>
 
 void domain_pause_for_debugger(void);
 
-#ifdef CONFIG_CRASH_DEBUG
-
-#include <xen/gdbstub.h>
-
 static inline bool debugger_trap_fatal(
     unsigned int vector, struct cpu_user_regs *regs)
 {
@@ -74,28 +56,10 @@ static inline bool debugger_trap_entry(
     return false;
 }
 
-#else
-
-static inline bool debugger_trap_fatal(
-    unsigned int vector, struct cpu_user_regs *regs)
-{
-    return false;
-}
-
-#define debugger_trap_immediate() ((void)0)
-
-static inline bool debugger_trap_entry(
-    unsigned int vector, struct cpu_user_regs *regs)
-{
-    return false;
-}
-
-#endif
-
 #ifdef CONFIG_GDBSX
 unsigned int dbg_rw_mem(unsigned long gva, XEN_GUEST_HANDLE_PARAM(void) buf,
                         unsigned int len, domid_t domid, bool toaddr,
                         uint64_t pgd3);
-#endif
+#endif /* CONFIG_GDBSX */
 
 #endif /* __X86_DEBUGGER_H__ */
diff --git a/xen/include/xen/debugger.h b/xen/include/xen/debugger.h
new file mode 100644
index 0000000000..64745fbe8f
--- /dev/null
+++ b/xen/include/xen/debugger.h
@@ -0,0 +1,69 @@
+/******************************************************************************
+ * Generic hooks into arch-dependent Xen.
+ *
+ * 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/>.
+ *
+ * Each debugger should define three functions here:
+ *
+ * 1. debugger_trap_entry():
+ *  Called at start of any synchronous fault or trap, before any other work
+ *  is done. The idea is that if your debugger deliberately caused the trap
+ *  (e.g. to implement breakpoints or data watchpoints) then you can take
+ *  appropriate action and return a non-zero value to cause early exit from
+ *  the trap function.
+ *
+ * 2. debugger_trap_fatal():
+ *  Called when Xen is about to give up and crash. Typically you will use this
+ *  hook to drop into a debug session. It can also be used to hook off
+ *  deliberately caused traps (which you then handle and return non-zero).
+ *
+ * 3. debugger_trap_immediate():
+ *  Called if we want to drop into a debugger now.  This is essentially the
+ *  same as debugger_trap_fatal, except that we use the current register state
+ *  rather than the state which was in effect when we took the trap.
+ *  For example: if we're dying because of an unhandled exception, we call
+ *  debugger_trap_fatal; if we're dying because of a panic() we call
+ *  debugger_trap_immediate().
+ */
+
+#ifndef __XEN_DEBUGGER_H__
+#define __XEN_DEBUGGER_H__
+
+#ifdef CONFIG_CRASH_DEBUG
+
+#include <asm/debugger.h>
+
+#else
+
+#include <asm/regs.h>
+#include <asm/processor.h>
+
+static inline void domain_pause_for_debugger(void)
+{
+}
+
+static inline bool debugger_trap_fatal(
+    unsigned int vector, const struct cpu_user_regs *regs)
+{
+    return false;
+}
+
+static inline void debugger_trap_immediate(void)
+{
+}
+
+static inline bool debugger_trap_entry(
+    unsigned int vector, const struct cpu_user_regs *regs)
+{
+    return false;
+}
+
+#endif /* CONFIG_CRASH_DEBUG */
+
+#endif /* __XEN_DEBUGGER_H__ */
-- 
2.30.0