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Date:      Mon, 21 Aug 2017 17:35:04 +0000 (UTC)
From:      John Baldwin <jhb@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org
Subject:   svn commit: r322761 - in stable/11/sys/arm64: arm64 include
Message-ID:  <201708211735.v7LHZ4UG023562@repo.freebsd.org>
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Author: jhb
Date: Mon Aug 21 17:35:04 2017
New Revision: 322761
URL: https://svnweb.freebsd.org/changeset/base/322761

Log:
  MFC 322437: Reliably enable debug exceptions on all CPUs.
  
  Previously, debug exceptions were only enabled on the boot CPU if
  DDB was enabled in the dbg_monitor_init() function.  APs also called
  this function, but since mp_machdep.c doesn't include opt_ddb.h, the
  APs ended up calling an empty stub defined in <machine/debug_monitor.h>
  instead of the real function.  Also, if DDB was not enabled in the kernel,
  the boot CPU would not enable debug exceptions.
  
  Fix this by adding a new dbg_init() function that always clears the OS
  lock to enable debug exceptions which the boot CPU and the APs call.
  This function also calls dbg_monitor_init() to enable hardware breakpoints
  from DDB on all CPUs if DDB is enabled.  Eventually base support for
  hardware breakpoints/watchpoints will need to move out of the DDB-only
  debug_monitor.c for use by userland debuggers.

Modified:
  stable/11/sys/arm64/arm64/debug_monitor.c
  stable/11/sys/arm64/arm64/machdep.c
  stable/11/sys/arm64/arm64/mp_machdep.c
  stable/11/sys/arm64/include/machdep.h
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/arm64/arm64/debug_monitor.c
==============================================================================
--- stable/11/sys/arm64/arm64/debug_monitor.c	Mon Aug 21 17:29:37 2017	(r322760)
+++ stable/11/sys/arm64/arm64/debug_monitor.c	Mon Aug 21 17:35:04 2017	(r322761)
@@ -453,15 +453,12 @@ dbg_monitor_init(void)
 {
 	u_int i;
 
-	/* Clear OS lock */
-	WRITE_SPECIALREG(OSLAR_EL1, 0);
-
 	/* Find out many breakpoints and watchpoints we can use */
 	dbg_watchpoint_num = ((READ_SPECIALREG(ID_AA64DFR0_EL1) >> 20) & 0xf) + 1;
 	dbg_breakpoint_num = ((READ_SPECIALREG(ID_AA64DFR0_EL1) >> 12) & 0xf) + 1;
 
 	if (bootverbose && PCPU_GET(cpuid) == 0) {
-		db_printf("%d watchpoints and %d breakpoints supported\n",
+		printf("%d watchpoints and %d breakpoints supported\n",
 		    dbg_watchpoint_num, dbg_breakpoint_num);
 	}
 

Modified: stable/11/sys/arm64/arm64/machdep.c
==============================================================================
--- stable/11/sys/arm64/arm64/machdep.c	Mon Aug 21 17:29:37 2017	(r322760)
+++ stable/11/sys/arm64/arm64/machdep.c	Mon Aug 21 17:35:04 2017	(r322761)
@@ -970,11 +970,24 @@ initarm(struct arm64_bootparams *abp)
 	mutex_init();
 	init_param2(physmem);
 
-	dbg_monitor_init();
+	dbg_init();
 	kdb_init();
 	pan_enable();
 
 	early_boot = 0;
+}
+
+void
+dbg_init(void)
+{
+
+	/* Clear OS lock */
+	WRITE_SPECIALREG(OSLAR_EL1, 0);
+
+	/* This permits DDB to use debug registers for watchpoints. */
+	dbg_monitor_init();
+
+	/* TODO: Eventually will need to initialize debug registers here. */
 }
 
 #ifdef DDB

Modified: stable/11/sys/arm64/arm64/mp_machdep.c
==============================================================================
--- stable/11/sys/arm64/arm64/mp_machdep.c	Mon Aug 21 17:29:37 2017	(r322760)
+++ stable/11/sys/arm64/arm64/mp_machdep.c	Mon Aug 21 17:35:04 2017	(r322761)
@@ -51,7 +51,6 @@ __FBSDID("$FreeBSD$");
 #include <vm/vm_extern.h>
 #include <vm/vm_kern.h>
 
-#include <machine/debug_monitor.h>
 #include <machine/intr.h>
 #include <machine/smp.h>
 #ifdef VFP
@@ -277,7 +276,7 @@ init_secondary(uint64_t cpu)
 	vfp_init();
 #endif
 
-	dbg_monitor_init();
+	dbg_init();
 	pan_enable();
 
 	/* Enable interrupts */

Modified: stable/11/sys/arm64/include/machdep.h
==============================================================================
--- stable/11/sys/arm64/include/machdep.h	Mon Aug 21 17:29:37 2017	(r322760)
+++ stable/11/sys/arm64/include/machdep.h	Mon Aug 21 17:35:04 2017	(r322761)
@@ -40,6 +40,7 @@ struct arm64_bootparams {
 extern vm_paddr_t physmap[];
 extern u_int physmap_idx;
 
+void dbg_init(void);
 void initarm(struct arm64_bootparams *);
 extern void (*pagezero)(void *);

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