Merge branch 'hw-breakpoint' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux into devel-stable

3 files changed, 91 insertions, 91 deletions

diff --git a/arch/arm/include/asm/cti.h b/arch/arm/include/asm/cti.h
index a0ada3ea4358..f2e5cad3f306 100644
--- a/arch/arm/include/asm/cti.h
+++ b/arch/arm/include/asm/cti.h
@@ -146,15 +146,7 @@ static inline void cti_irq_ack(struct cti *cti)
  */
 static inline void cti_unlock(struct cti *cti)
 {
-        void __iomem *base = cti->base;
-        unsigned long val;
-
-        val = __raw_readl(base + LOCKSTATUS);
-
-        if (val & 1) {
-                val = LOCKCODE;
-                __raw_writel(val, base + LOCKACCESS);
-        }
+        __raw_writel(LOCKCODE, cti->base + LOCKACCESS);
 }
 
 /**
@@ -166,14 +158,6 @@ static inline void cti_unlock(struct cti *cti)
  */
 static inline void cti_lock(struct cti *cti)
 {
-        void __iomem *base = cti->base;
-        unsigned long val;
-
-        val = __raw_readl(base + LOCKSTATUS);
-
-        if (!(val & 1)) {
-                val = ~LOCKCODE;
-                __raw_writel(val, base + LOCKACCESS);
-        }
+        __raw_writel(~LOCKCODE, cti->base + LOCKACCESS);
 }
 #endif
diff --git a/arch/arm/include/asm/hw_breakpoint.h b/arch/arm/include/asm/hw_breakpoint.h
index c190bc992f0e..01169dd723f1 100644
--- a/arch/arm/include/asm/hw_breakpoint.h
+++ b/arch/arm/include/asm/hw_breakpoint.h
@@ -98,12 +98,12 @@ static inline void decode_ctrl_reg(u32 reg,
 #define ARM_BASE_WCR            112
 
 /* Accessor macros for the debug registers. */
-#define ARM_DBG_READ(M, OP2, VAL) do {\
-        asm volatile("mrc p14, 0, %0, c0," #M ", " #OP2 : "=r" (VAL));\
+#define ARM_DBG_READ(N, M, OP2, VAL) do {\
+        asm volatile("mrc p14, 0, %0, " #N "," #M ", " #OP2 : "=r" (VAL));\
 } while (0)
 
-#define ARM_DBG_WRITE(M, OP2, VAL) do {\
-        asm volatile("mcr p14, 0, %0, c0," #M ", " #OP2 : : "r" (VAL));\
+#define ARM_DBG_WRITE(N, M, OP2, VAL) do {\
+        asm volatile("mcr p14, 0, %0, " #N "," #M ", " #OP2 : : "r" (VAL));\
 } while (0)
 
 struct notifier_block;
diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index 281bf3301241..5ff2e77782b1 100644
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -52,14 +52,14 @@ static u8 debug_arch;
 /* Maximum supported watchpoint length. */
 static u8 max_watchpoint_len;
 
-#define READ_WB_REG_CASE(OP2, M, VAL)           \
-        case ((OP2 << 4) + M):                  \
-                ARM_DBG_READ(c ## M, OP2, VAL); \
+#define READ_WB_REG_CASE(OP2, M, VAL)                   \
+        case ((OP2 << 4) + M):                          \
+                ARM_DBG_READ(c0, c ## M, OP2, VAL);     \
                 break
 
-#define WRITE_WB_REG_CASE(OP2, M, VAL)          \
-        case ((OP2 << 4) + M):                  \
-                ARM_DBG_WRITE(c ## M, OP2, VAL);\
+#define WRITE_WB_REG_CASE(OP2, M, VAL)                  \
+        case ((OP2 << 4) + M):                          \
+                ARM_DBG_WRITE(c0, c ## M, OP2, VAL);    \
                 break
 
 #define GEN_READ_WB_REG_CASES(OP2, VAL)         \
@@ -136,12 +136,12 @@ static u8 get_debug_arch(void)
 
         /* 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");
+                pr_warn_once("CPUID feature registers not supported. "
+                             "Assuming v6 debug is present.\n");
                 return ARM_DEBUG_ARCH_V6;
         }
 
-        ARM_DBG_READ(c0, 0, didr);
+        ARM_DBG_READ(c0, c0, 0, didr);
         return (didr >> 16) & 0xf;
 }
 
@@ -169,7 +169,7 @@ static int debug_exception_updates_fsr(void)
 static int get_num_wrp_resources(void)
 {
         u32 didr;
-        ARM_DBG_READ(c0, 0, didr);
+        ARM_DBG_READ(c0, c0, 0, didr);
         return ((didr >> 28) & 0xf) + 1;
 }
 
@@ -177,7 +177,7 @@ static int get_num_wrp_resources(void)
 static int get_num_brp_resources(void)
 {
         u32 didr;
-        ARM_DBG_READ(c0, 0, didr);
+        ARM_DBG_READ(c0, c0, 0, didr);
         return ((didr >> 24) & 0xf) + 1;
 }
 
@@ -228,19 +228,17 @@ static int get_num_brps(void)
  * be put into halting debug mode at any time by an external debugger
  * but there is nothing we can do to prevent that.
  */
-static int enable_monitor_mode(void)
+static int monitor_mode_enabled(void)
 {
         u32 dscr;
-        int ret = 0;
-
-        ARM_DBG_READ(c1, 0, dscr);
+        ARM_DBG_READ(c0, c1, 0, dscr);
+        return !!(dscr & ARM_DSCR_MDBGEN);
+}
 
-        /* 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;
-        }
+static int enable_monitor_mode(void)
+{
+        u32 dscr;
+        ARM_DBG_READ(c0, c1, 0, dscr);
 
         /* If monitor mode is already enabled, just return. */
         if (dscr & ARM_DSCR_MDBGEN)
@@ -250,24 +248,27 @@ static int enable_monitor_mode(void)
         switch (get_debug_arch()) {
         case ARM_DEBUG_ARCH_V6:
         case ARM_DEBUG_ARCH_V6_1:
-                ARM_DBG_WRITE(c1, 0, (dscr | ARM_DSCR_MDBGEN));
+                ARM_DBG_WRITE(c0, c1, 0, (dscr | ARM_DSCR_MDBGEN));
                 break;
         case ARM_DEBUG_ARCH_V7_ECP14:
         case ARM_DEBUG_ARCH_V7_1:
-                ARM_DBG_WRITE(c2, 2, (dscr | ARM_DSCR_MDBGEN));
+                ARM_DBG_WRITE(c0, c2, 2, (dscr | ARM_DSCR_MDBGEN));
+                isb();
                 break;
         default:
-                ret = -ENODEV;
-                goto out;
+                return -ENODEV;
         }
 
         /* Check that the write made it through. */
-        ARM_DBG_READ(c1, 0, dscr);
-        if (!(dscr & ARM_DSCR_MDBGEN))
-                ret = -EPERM;
+        ARM_DBG_READ(c0, c1, 0, dscr);
+        if (!(dscr & ARM_DSCR_MDBGEN)) {
+                pr_warn_once("Failed to enable monitor mode on CPU %d.\n",
+                                smp_processor_id());
+                return -EPERM;
+        }
 
 out:
-        return ret;
+        return 0;
 }
 
 int hw_breakpoint_slots(int type)
@@ -328,14 +329,9 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
 {
         struct arch_hw_breakpoint *info = counter_arch_bp(bp);
         struct perf_event **slot, **slots;
-        int i, max_slots, ctrl_base, val_base, ret = 0;
+        int i, max_slots, ctrl_base, val_base;
         u32 addr, ctrl;
 
-        /* Ensure that we are in monitor mode and halting mode is disabled. */
-        ret = enable_monitor_mode();
-        if (ret)
-                goto out;
-
         addr = info->address;
         ctrl = encode_ctrl_reg(info->ctrl) | 0x1;
 
@@ -362,9 +358,9 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
                 }
         }
 
-        if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot\n")) {
-                ret = -EBUSY;
-                goto out;
+        if (i == max_slots) {
+                pr_warning("Can't find any breakpoint slot\n");
+                return -EBUSY;
         }
 
         /* Override the breakpoint data with the step data. */
@@ -383,9 +379,7 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
 
         /* Setup the control register. */
         write_wb_reg(ctrl_base + i, ctrl);
-
-out:
-        return ret;
+        return 0;
 }
 
 void arch_uninstall_hw_breakpoint(struct perf_event *bp)
@@ -416,8 +410,10 @@ void arch_uninstall_hw_breakpoint(struct perf_event *bp)
                 }
         }
 
-        if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot\n"))
+        if (i == max_slots) {
+                pr_warning("Can't find any breakpoint slot\n");
                 return;
+        }
 
         /* Ensure that we disable the mismatch breakpoint. */
         if (info->ctrl.type != ARM_BREAKPOINT_EXECUTE &&
@@ -596,6 +592,10 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp)
         int ret = 0;
         u32 offset, alignment_mask = 0x3;
 
+        /* Ensure that we are in monitor debug mode. */
+        if (!monitor_mode_enabled())
+                return -ENODEV;
+
         /* Build the arch_hw_breakpoint. */
         ret = arch_build_bp_info(bp);
         if (ret)
@@ -858,7 +858,7 @@ static int hw_breakpoint_pending(unsigned long addr, unsigned int fsr,
                 local_irq_enable();
 
         /* We only handle watchpoints and hardware breakpoints. */
-        ARM_DBG_READ(c1, 0, dscr);
+        ARM_DBG_READ(c0, c1, 0, dscr);
 
         /* Perform perf callbacks. */
         switch (ARM_DSCR_MOE(dscr)) {
@@ -906,7 +906,7 @@ static struct undef_hook debug_reg_hook = {
 static void reset_ctrl_regs(void *unused)
 {
         int i, raw_num_brps, err = 0, cpu = smp_processor_id();
-        u32 dbg_power;
+        u32 val;
 
         /*
          * v7 debug contains save and restore registers so that debug state
@@ -919,23 +919,30 @@ static void reset_ctrl_regs(void *unused)
         switch (debug_arch) {
         case ARM_DEBUG_ARCH_V6:
         case ARM_DEBUG_ARCH_V6_1:
-                /* ARMv6 cores just need to reset the registers. */
-                goto reset_regs;
+                /* ARMv6 cores clear the registers out of reset. */
+                goto out_mdbgen;
         case 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)
+                ARM_DBG_READ(c1, c5, 4, val);
+                if ((val & 0x1) == 0)
                         err = -EPERM;
+
+                /*
+                 * Check whether we implement OS save and restore.
+                 */
+                ARM_DBG_READ(c1, c1, 4, val);
+                if ((val & 0x9) == 0)
+                        goto clear_vcr;
                 break;
         case ARM_DEBUG_ARCH_V7_1:
                 /*
                  * Ensure the OS double lock is clear.
                  */
-                asm volatile("mrc p14, 0, %0, c1, c3, 4" : "=r" (dbg_power));
-                if ((dbg_power & 0x1) == 1)
+                ARM_DBG_READ(c1, c3, 4, val);
+                if ((val & 0x1) == 1)
                         err = -EPERM;
                 break;
         }
@@ -947,24 +954,29 @@ static void reset_ctrl_regs(void *unused)
         }
 
         /*
-         * Unconditionally clear the lock by writing a value
+         * Unconditionally clear the OS lock by writing a value
          * other than 0xC5ACCE55 to the access register.
          */
-        asm volatile("mcr p14, 0, %0, c1, c0, 4" : : "r" (0));
+        ARM_DBG_WRITE(c1, c0, 4, 0);
         isb();
 
         /*
          * Clear any configured vector-catch events before
          * enabling monitor mode.
          */
-        asm volatile("mcr p14, 0, %0, c0, c7, 0" : : "r" (0));
+clear_vcr:
+        ARM_DBG_WRITE(c0, c7, 0, 0);
         isb();
 
-reset_regs:
-        if (enable_monitor_mode())
+        if (cpumask_intersects(&debug_err_mask, cpumask_of(cpu))) {
+                pr_warning("CPU %d failed to disable vector catch\n", cpu);
                 return;
+        }
 
-        /* We must also reset any reserved registers. */
+        /*
+         * The control/value register pairs are UNKNOWN out of reset so
+         * clear them to avoid spurious debug events.
+         */
         raw_num_brps = get_num_brp_resources();
         for (i = 0; i < raw_num_brps; ++i) {
                 write_wb_reg(ARM_BASE_BCR + i, 0UL);
@@ -975,6 +987,19 @@ reset_regs:
                 write_wb_reg(ARM_BASE_WCR + i, 0UL);
                 write_wb_reg(ARM_BASE_WVR + i, 0UL);
         }
+
+        if (cpumask_intersects(&debug_err_mask, cpumask_of(cpu))) {
+                pr_warning("CPU %d failed to clear debug register pairs\n", cpu);
+                return;
+        }
+
+        /*
+         * Have a crack at enabling monitor mode. We don't actually need
+         * it yet, but reporting an error early is useful if it fails.
+         */
+out_mdbgen:
+        if (enable_monitor_mode())
+                cpumask_or(&debug_err_mask, &debug_err_mask, cpumask_of(cpu));
 }
 
 static int __cpuinit dbg_reset_notify(struct notifier_block *self,
@@ -992,8 +1017,6 @@ 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()) {
@@ -1028,17 +1051,10 @@ 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,