diff options
Diffstat (limited to 'arch/arm/kernel/hw_breakpoint.c')
| -rw-r--r-- | arch/arm/kernel/hw_breakpoint.c | 68 |
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", |