Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[mv-sheeva.git] / arch / arm / kernel / hw_breakpoint.c

diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index c9f3f046757046010ea1f95d13321f676f202d0a..44b84fe6e1b0fdc544c6f306ed33384a33734fab 100644 (file)
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -137,11 +137,10 @@ static u8 get_debug_arch(void)
        u32 didr;
 
        /* Do we implement the extended CPUID interface? */
-       if (((read_cpuid_id() >> 16) & 0xf) != 0xf) {
-               pr_warning("CPUID feature registers not supported. "
-                               "Assuming v6 debug is present.\n");
+       if (WARN_ONCE((((read_cpuid_id() >> 16) & 0xf) != 0xf),
+           "CPUID feature registers not supported. "
+           "Assuming v6 debug is present.\n"))
                return ARM_DEBUG_ARCH_V6;
-       }
 
        ARM_DBG_READ(c0, 0, didr);
        return (didr >> 16) & 0xf;
@@ -152,6 +151,12 @@ u8 arch_get_debug_arch(void)
        return debug_arch;
 }
 
+static int debug_arch_supported(void)
+{
+       u8 arch = get_debug_arch();
+       return arch >= ARM_DEBUG_ARCH_V6 && arch <= ARM_DEBUG_ARCH_V7_ECP14;
+}
+
 /* Determine number of BRP register available. */
 static int get_num_brp_resources(void)
 {
@@ -268,6 +273,9 @@ out:
 
 int hw_breakpoint_slots(int type)
 {
+       if (!debug_arch_supported())
+               return 0;
+
        /*
         * We can be called early, so don't rely on
         * our static variables being initialised.
@@ -828,19 +836,32 @@ static int hw_breakpoint_pending(unsigned long addr, unsigned int fsr,
 /*
  * One-time initialisation.
  */
-static void reset_ctrl_regs(void *unused)
+static void reset_ctrl_regs(void *info)
 {
-       int i;
+       int i, cpu = smp_processor_id();
+       u32 dbg_power;
+       cpumask_t *cpumask = info;
 
        /*
         * v7 debug contains save and restore registers so that debug state
-        * can be maintained across low-power modes without leaving
-        * the debug logic powered up. It is IMPLEMENTATION DEFINED whether
-        * we can write to the debug registers out of reset, so we must
-        * unlock the OS Lock Access Register to avoid taking undefined
-        * instruction exceptions later on.
+        * can be maintained across low-power modes without leaving the debug
+        * logic powered up. It is IMPLEMENTATION DEFINED whether we can access
+        * the debug registers out of reset, so we must unlock the OS Lock
+        * Access Register to avoid taking undefined instruction exceptions
+        * later on.
         */
        if (debug_arch >= ARM_DEBUG_ARCH_V7_ECP14) {
+               /*
+                * Ensure sticky power-down is clear (i.e. debug logic is
+                * powered up).
+                */
+               asm volatile("mrc p14, 0, %0, c1, c5, 4" : "=r" (dbg_power));
+               if ((dbg_power & 0x1) == 0) {
+                       pr_warning("CPU %d debug is powered down!\n", cpu);
+                       cpumask_or(cpumask, cpumask, cpumask_of(cpu));
+                       return;
+               }
+
                /*
                 * Unconditionally clear the lock by writing a value
                 * other than 0xC5ACCE55 to the access register.
@@ -879,10 +900,11 @@ static struct notifier_block __cpuinitdata dbg_reset_nb = {
 static int __init arch_hw_breakpoint_init(void)
 {
        u32 dscr;
+       cpumask_t cpumask = { CPU_BITS_NONE };
 
        debug_arch = get_debug_arch();
 
-       if (debug_arch > ARM_DEBUG_ARCH_V7_ECP14) {
+       if (!debug_arch_supported()) {
                pr_info("debug architecture 0x%x unsupported.\n", debug_arch);
                return 0;
        }
@@ -899,18 +921,24 @@ static int __init arch_hw_breakpoint_init(void)
                pr_info("%d breakpoint(s) reserved for watchpoint "
                                "single-step.\n", core_num_reserved_brps);
 
+       /*
+        * Reset the breakpoint resources. We assume that a halting
+        * debugger will leave the world in a nice state for us.
+        */
+       on_each_cpu(reset_ctrl_regs, &cpumask, 1);
+       if (!cpumask_empty(&cpumask)) {
+               core_num_brps = 0;
+               core_num_reserved_brps = 0;
+               core_num_wrps = 0;
+               return 0;
+       }
+
        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 4 bytes.");
+                          "watchpoint size of %u bytes.", max_watchpoint_len);
        } else {
-               /*
-                * Reset the breakpoint resources. We assume that a halting
-                * debugger will leave the world in a nice state for us.
-                */
-               smp_call_function(reset_ctrl_regs, NULL, 1);
-               reset_ctrl_regs(NULL);
-
                /* Work out the maximum supported watchpoint length. */
                max_watchpoint_len = get_max_wp_len();
                pr_info("maximum watchpoint size is %u bytes.\n",