ARM: hw_breakpoint: fix monitor mode detection with v7.1

[~andy/linux] / arch / arm / kernel / hw_breakpoint.c

diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index 76a650a1a1d78f785a7aff305a2c5ec43dc01f14..c87ea68d64ae56fe1dc2471922efe333cf3d2c6d 100644 (file)
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -235,13 +235,6 @@ static int enable_monitor_mode(void)
 
        ARM_DBG_READ(c1, 0, dscr);
 
-       /* Ensure that halting mode is disabled. */
-       if (WARN_ONCE(dscr & ARM_DSCR_HDBGEN,
-               "halting debug mode enabled. Unable to access hardware resources.\n")) {
-               ret = -EPERM;
-               goto out;
-       }
-
        /* If monitor mode is already enabled, just return. */
        if (dscr & ARM_DSCR_MDBGEN)
                goto out;
@@ -255,6 +248,7 @@ static int enable_monitor_mode(void)
        case ARM_DEBUG_ARCH_V7_ECP14:
        case ARM_DEBUG_ARCH_V7_1:
                ARM_DBG_WRITE(c2, 2, (dscr | ARM_DSCR_MDBGEN));
+               isb();
                break;
        default:
                ret = -ENODEV;
@@ -1000,8 +994,6 @@ static struct notifier_block __cpuinitdata dbg_reset_nb = {
 
 static int __init arch_hw_breakpoint_init(void)
 {
-       u32 dscr;
-
        debug_arch = get_debug_arch();
 
        if (!debug_arch_supported()) {
@@ -1036,17 +1028,10 @@ static int __init arch_hw_breakpoint_init(void)
                core_num_brps, core_has_mismatch_brps() ? "(+1 reserved) " :
                "", core_num_wrps);
 
-       ARM_DBG_READ(c1, 0, dscr);
-       if (dscr & ARM_DSCR_HDBGEN) {
-               max_watchpoint_len = 4;
-               pr_warning("halting debug mode enabled. Assuming maximum watchpoint size of %u bytes.\n",
-                          max_watchpoint_len);
-       } else {
-               /* Work out the maximum supported watchpoint length. */
-               max_watchpoint_len = get_max_wp_len();
-               pr_info("maximum watchpoint size is %u bytes.\n",
-                               max_watchpoint_len);
-       }
+       /* Work out the maximum supported watchpoint length. */
+       max_watchpoint_len = get_max_wp_len();
+       pr_info("maximum watchpoint size is %u bytes.\n",
+                       max_watchpoint_len);
 
        /* Register debug fault handler. */
        hook_fault_code(FAULT_CODE_DEBUG, hw_breakpoint_pending, SIGTRAP,