Merge tag 'arc-4.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

Pull ARC updates from Vineet Gupta:

 - perf fixes/improvements

 - misc cleanups

* tag 'arc-4.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: perf: don't add code for impossible case
  ARC: perf: Rename DT binding to not confuse with power mgmt
  ARC: perf: add user space attribution in callchains
  ARC: perf: Add kernel callchain support
  ARC: perf: support cache hit/miss ratio
  ARC: perf: Add some comments/debug stuff
  ARC: perf: make @arc_pmu static global
  ARC: mem init spring cleaning - No functional changes
  ARC: Fix RTT boot printing
  ARC: fold __builtin_constant_p() into test_bit()
  ARC: rename unhandled exception handler
  ARC: cosmetic: Remove unused ECR bitfield masks
  ARC: Fix WRITE_BCR
  ARC: [nsimosci] Update defconfig
  arc: copy_thread(): rename 'arg' argument to 'kthread_arg'

4 files changed, 69 insertions, 22 deletions

diff --git a/arch/arc/kernel/perf_event.c b/arch/arc/kernel/perf_event.c
index ae1c485cbc68..fd2ec50102f2 100644
--- a/arch/arc/kernel/perf_event.c
+++ b/arch/arc/kernel/perf_event.c
@@ -16,6 +16,7 @@
 #include <linux/perf_event.h>
 #include <linux/platform_device.h>
 #include <asm/arcregs.h>
+#include <asm/stacktrace.h>
 
 struct arc_pmu {
 	struct pmu	pmu;
@@ -25,6 +26,46 @@ struct arc_pmu {
 	int		ev_hw_idx[PERF_COUNT_ARC_HW_MAX];
 };
 
+struct arc_callchain_trace {
+	int depth;
+	void *perf_stuff;
+};
+
+static int callchain_trace(unsigned int addr, void *data)
+{
+	struct arc_callchain_trace *ctrl = data;
+	struct perf_callchain_entry *entry = ctrl->perf_stuff;
+	perf_callchain_store(entry, addr);
+
+	if (ctrl->depth++ < 3)
+		return 0;
+
+	return -1;
+}
+
+void
+perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs)
+{
+	struct arc_callchain_trace ctrl = {
+		.depth = 0,
+		.perf_stuff = entry,
+	};
+
+	arc_unwind_core(NULL, regs, callchain_trace, &ctrl);
+}
+
+void
+perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
+{
+	/*
+	 * User stack can't be unwound trivially with kernel dwarf unwinder
+	 * So for now just record the user PC
+	 */
+	perf_callchain_store(entry, instruction_pointer(regs));
+}
+
+static struct arc_pmu *arc_pmu;
+
 /* read counter #idx; note that counter# != event# on ARC! */
 static uint64_t arc_pmu_read_counter(int idx)
 {
@@ -47,7 +88,6 @@ static uint64_t arc_pmu_read_counter(int idx)
 static void arc_perf_event_update(struct perf_event *event,
 				  struct hw_perf_event *hwc, int idx)
 {
-	struct arc_pmu *arc_pmu = container_of(event->pmu, struct arc_pmu, pmu);
 	uint64_t prev_raw_count, new_raw_count;
 	int64_t delta;
 
@@ -89,13 +129,16 @@ static int arc_pmu_cache_event(u64 config)
 	if (ret == CACHE_OP_UNSUPPORTED)
 		return -ENOENT;
 
+	pr_debug("init cache event: type/op/result %d/%d/%d with h/w %d \'%s\'\n",
+		 cache_type, cache_op, cache_result, ret,
+		 arc_pmu_ev_hw_map[ret]);
+
 	return ret;
 }
 
 /* initializes hw_perf_event structure if event is supported */
 static int arc_pmu_event_init(struct perf_event *event)
 {
-	struct arc_pmu *arc_pmu = container_of(event->pmu, struct arc_pmu, pmu);
 	struct hw_perf_event *hwc = &event->hw;
 	int ret;
 
@@ -106,8 +149,9 @@ static int arc_pmu_event_init(struct perf_event *event)
 		if (arc_pmu->ev_hw_idx[event->attr.config] < 0)
 			return -ENOENT;
 		hwc->config = arc_pmu->ev_hw_idx[event->attr.config];
-		pr_debug("initializing event %d with cfg %d\n",
-			 (int) event->attr.config, (int) hwc->config);
+		pr_debug("init event %d with h/w %d \'%s\'\n",
+			 (int) event->attr.config, (int) hwc->config,
+			 arc_pmu_ev_hw_map[event->attr.config]);
 		return 0;
 	case PERF_TYPE_HW_CACHE:
 		ret = arc_pmu_cache_event(event->attr.config);
@@ -183,8 +227,6 @@ static void arc_pmu_stop(struct perf_event *event, int flags)
 
 static void arc_pmu_del(struct perf_event *event, int flags)
 {
-	struct arc_pmu *arc_pmu = container_of(event->pmu, struct arc_pmu, pmu);
-
 	arc_pmu_stop(event, PERF_EF_UPDATE);
 	__clear_bit(event->hw.idx, arc_pmu->used_mask);
 
@@ -194,7 +236,6 @@ static void arc_pmu_del(struct perf_event *event, int flags)
 /* allocate hardware counter and optionally start counting */
 static int arc_pmu_add(struct perf_event *event, int flags)
 {
-	struct arc_pmu *arc_pmu = container_of(event->pmu, struct arc_pmu, pmu);
 	struct hw_perf_event *hwc = &event->hw;
 	int idx = hwc->idx;
 
@@ -247,10 +288,7 @@ static int arc_pmu_device_probe(struct platform_device *pdev)
 	BUG_ON(pct_bcr.c > ARC_PMU_MAX_HWEVENTS);
 
 	READ_BCR(ARC_REG_CC_BUILD, cc_bcr);
-	if (!cc_bcr.v) {
-		pr_err("Performance counters exist, but no countable conditions?\n");
-		return -ENODEV;
-	}
+	BUG_ON(!cc_bcr.v); /* Counters exist but No countable conditions ? */
 
 	arc_pmu = devm_kzalloc(&pdev->dev, sizeof(struct arc_pmu), GFP_KERNEL);
 	if (!arc_pmu)
@@ -263,19 +301,22 @@ static int arc_pmu_device_probe(struct platform_device *pdev)
 		arc_pmu->n_counters, arc_pmu->counter_size, cc_bcr.c);
 
 	cc_name.str[8] = 0;
-	for (i = 0; i < PERF_COUNT_HW_MAX; i++)
+	for (i = 0; i < PERF_COUNT_ARC_HW_MAX; i++)
 		arc_pmu->ev_hw_idx[i] = -1;
 
+	/* loop thru all available h/w condition indexes */
 	for (j = 0; j < cc_bcr.c; j++) {
 		write_aux_reg(ARC_REG_CC_INDEX, j);
 		cc_name.indiv.word0 = read_aux_reg(ARC_REG_CC_NAME0);
 		cc_name.indiv.word1 = read_aux_reg(ARC_REG_CC_NAME1);
+
+		/* See if it has been mapped to a perf event_id */
 		for (i = 0; i < ARRAY_SIZE(arc_pmu_ev_hw_map); i++) {
 			if (arc_pmu_ev_hw_map[i] &&
 			    !strcmp(arc_pmu_ev_hw_map[i], cc_name.str) &&
 			    strlen(arc_pmu_ev_hw_map[i])) {
-				pr_debug("mapping %d to idx %d with name %s\n",
-					 i, j, cc_name.str);
+				pr_debug("mapping perf event %2d to h/w event \'%8s\' (idx %d)\n",
+					 i, cc_name.str, j);
 				arc_pmu->ev_hw_idx[i] = j;
 			}
 		}
@@ -302,7 +343,7 @@ static int arc_pmu_device_probe(struct platform_device *pdev)
 
 #ifdef CONFIG_OF
 static const struct of_device_id arc_pmu_match[] = {
-	{ .compatible = "snps,arc700-pmu" },
+	{ .compatible = "snps,arc700-pct" },
 	{},
 };
 MODULE_DEVICE_TABLE(of, arc_pmu_match);
@@ -310,7 +351,7 @@ MODULE_DEVICE_TABLE(of, arc_pmu_match);
 
 static struct platform_driver arc_pmu_driver = {
 	.driver	= {
-		.name		= "arc700-pmu",
+		.name		= "arc700-pct",
 		.of_match_table = of_match_ptr(arc_pmu_match),
 	},
 	.probe		= arc_pmu_device_probe,
diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c
index f46efd14059d..e095c557afdd 100644
--- a/arch/arc/kernel/process.c
+++ b/arch/arc/kernel/process.c
@@ -49,7 +49,10 @@ void arch_cpu_idle(void)
 
 asmlinkage void ret_from_fork(void);
 
-/* Layout of Child kernel mode stack as setup at the end of this function is
+/*
+ * Copy architecture-specific thread state
+ *
+ * Layout of Child kernel mode stack as setup at the end of this function is
  *
  * |     ...        |
  * |     ...        |
@@ -81,7 +84,7 @@ asmlinkage void ret_from_fork(void);
  * ------------------  <===== END of PAGE
  */
 int copy_thread(unsigned long clone_flags,
-		unsigned long usp, unsigned long arg,
+		unsigned long usp, unsigned long kthread_arg,
 		struct task_struct *p)
 {
 	struct pt_regs *c_regs;        /* child's pt_regs */
@@ -112,7 +115,7 @@ int copy_thread(unsigned long clone_flags,
 	if (unlikely(p->flags & PF_KTHREAD)) {
 		memset(c_regs, 0, sizeof(struct pt_regs));
 
-		c_callee->r13 = arg; /* argument to kernel thread */
+		c_callee->r13 = kthread_arg;
 		c_callee->r14 = usp;  /* function */
 
 		return 0;
diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c
index 900f68a70088..1d167c6df8ca 100644
--- a/arch/arc/kernel/setup.c
+++ b/arch/arc/kernel/setup.c
@@ -120,7 +120,10 @@ static void read_arc_build_cfg_regs(void)
 	READ_BCR(ARC_REG_SMART_BCR, bcr);
 	cpu->extn.smart = bcr.ver ? 1 : 0;
 
-	cpu->extn.debug = cpu->extn.ap | cpu->extn.smart;
+	READ_BCR(ARC_REG_RTT_BCR, bcr);
+	cpu->extn.rtt = bcr.ver ? 1 : 0;
+
+	cpu->extn.debug = cpu->extn.ap | cpu->extn.smart | cpu->extn.rtt;
 }
 
 static const struct cpuinfo_data arc_cpu_tbl[] = {
diff --git a/arch/arc/kernel/traps.c b/arch/arc/kernel/traps.c
index 3eadfdabc322..c927aa84e652 100644
--- a/arch/arc/kernel/traps.c
+++ b/arch/arc/kernel/traps.c
@@ -42,7 +42,7 @@ void die(const char *str, struct pt_regs *regs, unsigned long address)
  *  -for kernel, chk if due to copy_(to|from)_user, otherwise die()
  */
 static noinline int
-handle_exception(const char *str, struct pt_regs *regs, siginfo_t *info)
+unhandled_exception(const char *str, struct pt_regs *regs, siginfo_t *info)
 {
 	if (user_mode(regs)) {
 		struct task_struct *tsk = current;
@@ -71,7 +71,7 @@ int name(unsigned long address, struct pt_regs *regs) \
 		.si_code  = sicode,		\
 		.si_addr = (void __user *)address,	\
 	};					\
-	return handle_exception(str, regs, &info);\
+	return unhandled_exception(str, regs, &info);\
 }
 
 /*