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Diffstat (limited to 'arch/arm/kernel/hw_breakpoint.c')
-rw-r--r--arch/arm/kernel/hw_breakpoint.c68
1 files changed, 48 insertions, 20 deletions
diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index c9f3f0467570..44b84fe6e1b0 100644
--- 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.
@@ -828,20 +836,33 @@ 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",