5 files changed, 45 insertions, 17 deletions

diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index c9b68d07ac4f..b9602ee06deb 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c
@@ -1973,7 +1973,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
 		.pvr_mask		= 0xffff0000,
 		.pvr_value		= 0x80240000,
 		.cpu_name		= "e5500",
-		.cpu_features		= CPU_FTRS_E500MC,
+		.cpu_features		= CPU_FTRS_E5500,
 		.cpu_user_features	= COMMON_USER_BOOKE,
 		.mmu_features		= MMU_FTR_TYPE_FSL_E | MMU_FTR_BIG_PHYS |
 			MMU_FTR_USE_TLBILX,
diff --git a/arch/powerpc/kernel/crash.c b/arch/powerpc/kernel/crash.c
index 3d3d416339dd..5b5e1f002a8e 100644
--- a/arch/powerpc/kernel/crash.c
+++ b/arch/powerpc/kernel/crash.c
@@ -163,7 +163,7 @@ static void crash_kexec_prepare_cpus(int cpu)
 }
 
 /* wait for all the CPUs to hit real mode but timeout if they don't come in */
-#if defined(CONFIG_PPC_STD_MMU_64) && defined(CONFIG_SMP)
+#ifdef CONFIG_PPC_STD_MMU_64
 static void crash_kexec_wait_realmode(int cpu)
 {
 	unsigned int msecs;
@@ -188,9 +188,7 @@ static void crash_kexec_wait_realmode(int cpu)
 	}
 	mb();
 }
-#else
-static inline void crash_kexec_wait_realmode(int cpu) {}
-#endif
+#endif	/* CONFIG_PPC_STD_MMU_64 */
 
 /*
  * This function will be called by secondary cpus or by kexec cpu
@@ -235,7 +233,9 @@ void crash_kexec_secondary(struct pt_regs *regs)
 	crash_ipi_callback(regs);
 }
 
-#else
+#else	/* ! CONFIG_SMP */
+static inline void crash_kexec_wait_realmode(int cpu) {}
+
 static void crash_kexec_prepare_cpus(int cpu)
 {
 	/*
@@ -255,7 +255,7 @@ void crash_kexec_secondary(struct pt_regs *regs)
 {
 	cpus_in_sr = CPU_MASK_NONE;
 }
-#endif
+#endif	/* CONFIG_SMP */
 
 /*
  * Register a function to be called on shutdown.  Only use this if you
diff --git a/arch/powerpc/kernel/legacy_serial.c b/arch/powerpc/kernel/legacy_serial.c
index c834757bebc0..2b97b80d6d7d 100644
--- a/arch/powerpc/kernel/legacy_serial.c
+++ b/arch/powerpc/kernel/legacy_serial.c
@@ -330,9 +330,11 @@ void __init find_legacy_serial_ports(void)
 		if (!parent)
 			continue;
 		if (of_match_node(legacy_serial_parents, parent) != NULL) {
-			index = add_legacy_soc_port(np, np);
-			if (index >= 0 && np == stdout)
-				legacy_serial_console = index;
+			if (of_device_is_available(np)) {
+				index = add_legacy_soc_port(np, np);
+				if (index >= 0 && np == stdout)
+					legacy_serial_console = index;
+			}
 		}
 		of_node_put(parent);
 	}
diff --git a/arch/powerpc/kernel/perf_event.c b/arch/powerpc/kernel/perf_event.c
index c4063b7f49a0..822f63008ae1 100644
--- a/arch/powerpc/kernel/perf_event.c
+++ b/arch/powerpc/kernel/perf_event.c
@@ -398,6 +398,25 @@ static int check_excludes(struct perf_event **ctrs, unsigned int cflags[],
 	return 0;
 }
 
+static u64 check_and_compute_delta(u64 prev, u64 val)
+{
+	u64 delta = (val - prev) & 0xfffffffful;
+
+	/*
+	 * POWER7 can roll back counter values, if the new value is smaller
+	 * than the previous value it will cause the delta and the counter to
+	 * have bogus values unless we rolled a counter over.  If a coutner is
+	 * rolled back, it will be smaller, but within 256, which is the maximum
+	 * number of events to rollback at once.  If we dectect a rollback
+	 * return 0.  This can lead to a small lack of precision in the
+	 * counters.
+	 */
+	if (prev > val && (prev - val) < 256)
+		delta = 0;
+
+	return delta;
+}
+
 static void power_pmu_read(struct perf_event *event)
 {
 	s64 val, delta, prev;
@@ -416,10 +435,11 @@ static void power_pmu_read(struct perf_event *event)
 		prev = local64_read(&event->hw.prev_count);
 		barrier();
 		val = read_pmc(event->hw.idx);
+		delta = check_and_compute_delta(prev, val);
+		if (!delta)
+			return;
 	} while (local64_cmpxchg(&event->hw.prev_count, prev, val) != prev);
 
-	/* The counters are only 32 bits wide */
-	delta = (val - prev) & 0xfffffffful;
 	local64_add(delta, &event->count);
 	local64_sub(delta, &event->hw.period_left);
 }
@@ -449,8 +469,9 @@ static void freeze_limited_counters(struct cpu_hw_events *cpuhw,
 		val = (event->hw.idx == 5) ? pmc5 : pmc6;
 		prev = local64_read(&event->hw.prev_count);
 		event->hw.idx = 0;
-		delta = (val - prev) & 0xfffffffful;
-		local64_add(delta, &event->count);
+		delta = check_and_compute_delta(prev, val);
+		if (delta)
+			local64_add(delta, &event->count);
 	}
 }
 
@@ -458,14 +479,16 @@ static void thaw_limited_counters(struct cpu_hw_events *cpuhw,
 				  unsigned long pmc5, unsigned long pmc6)
 {
 	struct perf_event *event;
-	u64 val;
+	u64 val, prev;
 	int i;
 
 	for (i = 0; i < cpuhw->n_limited; ++i) {
 		event = cpuhw->limited_counter[i];
 		event->hw.idx = cpuhw->limited_hwidx[i];
 		val = (event->hw.idx == 5) ? pmc5 : pmc6;
-		local64_set(&event->hw.prev_count, val);
+		prev = local64_read(&event->hw.prev_count);
+		if (check_and_compute_delta(prev, val))
+			local64_set(&event->hw.prev_count, val);
 		perf_event_update_userpage(event);
 	}
 }
@@ -1197,7 +1220,7 @@ static void record_and_restart(struct perf_event *event, unsigned long val,
 
 	/* we don't have to worry about interrupts here */
 	prev = local64_read(&event->hw.prev_count);
-	delta = (val - prev) & 0xfffffffful;
+	delta = check_and_compute_delta(prev, val);
 	local64_add(delta, &event->count);
 
 	/*
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 375480c56eb9..f33acfd872ad 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -229,6 +229,9 @@ static u64 scan_dispatch_log(u64 stop_tb)
 	u64 stolen = 0;
 	u64 dtb;
 
+	if (!dtl)
+		return 0;
+
 	if (i == vpa->dtl_idx)
 		return 0;
 	while (i < vpa->dtl_idx) {