Merge branch 'for-linus' of git://git.linaro.org/people/rmk/linux-arm

Pull ARM updates from Russell King:
 "First ARM push of this merge window, post me coming back from holiday.
  This is what has been in linux-next for the last few weeks.  Not much
  to say which isn't described by the commit summaries."

* 'for-linus' of git://git.linaro.org/people/rmk/linux-arm: (32 commits)
  ARM: 7463/1: topology: Update cpu_power according to DT information
  ARM: 7462/1: topology: factorize the update of sibling masks
  ARM: 7461/1: topology: Add arch_scale_freq_power function
  ARM: 7456/1: ptrace: provide separate functions for tracing syscall {entry,exit}
  ARM: 7455/1: audit: move syscall auditing until after ptrace SIGTRAP handling
  ARM: 7454/1: entry: don't bother with syscall tracing on ret_from_fork path
  ARM: 7453/1: audit: only allow syscall auditing for pure EABI userspace
  ARM: 7452/1: delay: allow timer-based delay implementation to be selected
  ARM: 7451/1: arch timer: implement read_current_timer and get_cycles
  ARM: 7450/1: dcache: select DCACHE_WORD_ACCESS for little-endian ARMv6+ CPUs
  ARM: 7449/1: use generic strnlen_user and strncpy_from_user functions
  ARM: 7448/1: perf: remove arm_perf_pmu_ids global enumeration
  ARM: 7447/1: rwlocks: remove unused branch labels from trylock routines
  ARM: 7446/1: spinlock: use ticket algorithm for ARMv6+ locking implementation
  ARM: 7445/1: mm: update CONTEXTIDR register to contain PID of current process
  ARM: 7444/1: kernel: add arch-timer C3STOP feature
  ARM: 7460/1: remove asm/locks.h
  ARM: 7439/1: head.S: simplify initial page table mapping
  ARM: 7437/1: zImage: Allow DTB command line concatenation with ATAG_CMDLINE
  ARM: 7436/1: Do not map the vectors page as write-through on UP systems
  ...

12 files changed, 345 insertions, 131 deletions

diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c
index dd58035..cf25880 100644
--- a/arch/arm/kernel/arch_timer.c
+++ b/arch/arm/kernel/arch_timer.c
@@ -32,6 +32,8 @@ static int arch_timer_ppi2;
 
 static struct clock_event_device __percpu **arch_timer_evt;
 
+extern void init_current_timer_delay(unsigned long freq);
+
 /*
  * Architected system timer support.
  */
@@ -137,7 +139,7 @@ static int __cpuinit arch_timer_setup(struct clock_event_device *clk)
 	/* Be safe... */
 	arch_timer_disable();
 
-	clk->features = CLOCK_EVT_FEAT_ONESHOT;
+	clk->features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP;
 	clk->name = "arch_sys_timer";
 	clk->rating = 450;
 	clk->set_mode = arch_timer_set_mode;
@@ -223,6 +225,14 @@ static cycle_t arch_counter_read(struct clocksource *cs)
 	return arch_counter_get_cntpct();
 }
 
+int read_current_timer(unsigned long *timer_val)
+{
+	if (!arch_timer_rate)
+		return -ENXIO;
+	*timer_val = arch_counter_get_cntpct();
+	return 0;
+}
+
 static struct clocksource clocksource_counter = {
 	.name	= "arch_sys_counter",
 	.rating	= 400,
@@ -296,6 +306,7 @@ static int __init arch_timer_register(void)
 	if (err)
 		goto out_free_irq;
 
+	init_current_timer_delay(arch_timer_rate);
 	return 0;
 
 out_free_irq:
diff --git a/arch/arm/kernel/armksyms.c b/arch/arm/kernel/armksyms.c
index b57c75e..60d3b73 100644
--- a/arch/arm/kernel/armksyms.c
+++ b/arch/arm/kernel/armksyms.c
@@ -49,8 +49,7 @@ extern void __aeabi_ulcmp(void);
 extern void fpundefinstr(void);
 
 	/* platform dependent support */
-EXPORT_SYMBOL(__udelay);
-EXPORT_SYMBOL(__const_udelay);
+EXPORT_SYMBOL(arm_delay_ops);
 
 	/* networking */
 EXPORT_SYMBOL(csum_partial);
@@ -87,10 +86,6 @@ EXPORT_SYMBOL(memmove);
 EXPORT_SYMBOL(memchr);
 EXPORT_SYMBOL(__memzero);
 
-	/* user mem (segment) */
-EXPORT_SYMBOL(__strnlen_user);
-EXPORT_SYMBOL(__strncpy_from_user);
-
 #ifdef CONFIG_MMU
 EXPORT_SYMBOL(copy_page);
 
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 4afed88..49d9f93 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -95,13 +95,7 @@ ENDPROC(ret_to_user)
 ENTRY(ret_from_fork)
 	bl	schedule_tail
 	get_thread_info tsk
-	ldr	r1, [tsk, #TI_FLAGS]		@ check for syscall tracing
 	mov	why, #1
-	tst	r1, #_TIF_SYSCALL_WORK		@ are we tracing syscalls?
-	beq	ret_slow_syscall
-	mov	r1, sp
-	mov	r0, #1				@ trace exit [IP = 1]
-	bl	syscall_trace
 	b	ret_slow_syscall
 ENDPROC(ret_from_fork)
 
@@ -448,10 +442,9 @@ ENDPROC(vector_swi)
 	 * context switches, and waiting for our parent to respond.
 	 */
 __sys_trace:
-	mov	r2, scno
-	add	r1, sp, #S_OFF
-	mov	r0, #0				@ trace entry [IP = 0]
-	bl	syscall_trace
+	mov	r1, scno
+	add	r0, sp, #S_OFF
+	bl	syscall_trace_enter
 
 	adr	lr, BSYM(__sys_trace_return)	@ return address
 	mov	scno, r0			@ syscall number (possibly new)
@@ -463,10 +456,9 @@ __sys_trace:
 
 __sys_trace_return:
 	str	r0, [sp, #S_R0 + S_OFF]!	@ save returned r0
-	mov	r2, scno
-	mov	r1, sp
-	mov	r0, #1				@ trace exit [IP = 1]
-	bl	syscall_trace
+	mov	r1, scno
+	mov	r0, sp
+	bl	syscall_trace_exit
 	b	ret_slow_syscall
 
 	.align	5
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 835898e..3db960e 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -55,14 +55,6 @@
 	add	\rd, \phys, #TEXT_OFFSET - PG_DIR_SIZE
 	.endm
 
-#ifdef CONFIG_XIP_KERNEL
-#define KERNEL_START	XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
-#define KERNEL_END	_edata_loc
-#else
-#define KERNEL_START	KERNEL_RAM_VADDR
-#define KERNEL_END	_end
-#endif
-
 /*
  * Kernel startup entry point.
  * ---------------------------
@@ -218,51 +210,46 @@ __create_page_tables:
 	blo	1b
 
 	/*
-	 * Now setup the pagetables for our kernel direct
-	 * mapped region.
+	 * Map our RAM from the start to the end of the kernel .bss section.
 	 */
-	mov	r3, pc
-	mov	r3, r3, lsr #SECTION_SHIFT
-	orr	r3, r7, r3, lsl #SECTION_SHIFT
-	add	r0, r4,  #(KERNEL_START & 0xff000000) >> (SECTION_SHIFT - PMD_ORDER)
-	str	r3, [r0, #((KERNEL_START & 0x00f00000) >> SECTION_SHIFT) << PMD_ORDER]!
-	ldr	r6, =(KERNEL_END - 1)
-	add	r0, r0, #1 << PMD_ORDER
+	add	r0, r4, #PAGE_OFFSET >> (SECTION_SHIFT - PMD_ORDER)
+	ldr	r6, =(_end - 1)
+	orr	r3, r8, r7
 	add	r6, r4, r6, lsr #(SECTION_SHIFT - PMD_ORDER)
-1:	cmp	r0, r6
+1:	str	r3, [r0], #1 << PMD_ORDER
 	add	r3, r3, #1 << SECTION_SHIFT
-	strls	r3, [r0], #1 << PMD_ORDER
+	cmp	r0, r6
 	bls	1b
 
 #ifdef CONFIG_XIP_KERNEL
 	/*
-	 * Map some ram to cover our .data and .bss areas.
+	 * Map the kernel image separately as it is not located in RAM.
 	 */
-	add	r3, r8, #TEXT_OFFSET
-	orr	r3, r3, r7
-	add	r0, r4,  #(KERNEL_RAM_VADDR & 0xff000000) >> (SECTION_SHIFT - PMD_ORDER)
-	str	r3, [r0, #(KERNEL_RAM_VADDR & 0x00f00000) >> (SECTION_SHIFT - PMD_ORDER)]!
-	ldr	r6, =(_end - 1)
-	add	r0, r0, #4
+#define XIP_START XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
+	mov	r3, pc
+	mov	r3, r3, lsr #SECTION_SHIFT
+	orr	r3, r7, r3, lsl #SECTION_SHIFT
+	add	r0, r4,  #(XIP_START & 0xff000000) >> (SECTION_SHIFT - PMD_ORDER)
+	str	r3, [r0, #((XIP_START & 0x00f00000) >> SECTION_SHIFT) << PMD_ORDER]!
+	ldr	r6, =(_edata_loc - 1)
+	add	r0, r0, #1 << PMD_ORDER
 	add	r6, r4, r6, lsr #(SECTION_SHIFT - PMD_ORDER)
 1:	cmp	r0, r6
-	add	r3, r3, #1 << 20
-	strls	r3, [r0], #4
+	add	r3, r3, #1 << SECTION_SHIFT
+	strls	r3, [r0], #1 << PMD_ORDER
 	bls	1b
 #endif
 
 	/*
-	 * Then map boot params address in r2 or the first 1MB (2MB with LPAE)
-	 * of ram if boot params address is not specified.
+	 * Then map boot params address in r2 if specified.
 	 */
 	mov	r0, r2, lsr #SECTION_SHIFT
 	movs	r0, r0, lsl #SECTION_SHIFT
-	moveq	r0, r8
-	sub	r3, r0, r8
-	add	r3, r3, #PAGE_OFFSET
-	add	r3, r4, r3, lsr #(SECTION_SHIFT - PMD_ORDER)
-	orr	r6, r7, r0
-	str	r6, [r3]
+	subne	r3, r0, r8
+	addne	r3, r3, #PAGE_OFFSET
+	addne	r3, r4, r3, lsr #(SECTION_SHIFT - PMD_ORDER)
+	orrne	r6, r7, r0
+	strne	r6, [r3]
 
 #ifdef CONFIG_DEBUG_LL
 #if !defined(CONFIG_DEBUG_ICEDCC) && !defined(CONFIG_DEBUG_SEMIHOSTING)
diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index a02eada..ab243b8 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -47,17 +47,14 @@ static DEFINE_PER_CPU(struct pmu_hw_events, cpu_hw_events);
 /* Set at runtime when we know what CPU type we are. */
 static struct arm_pmu *cpu_pmu;
 
-enum arm_perf_pmu_ids
-armpmu_get_pmu_id(void)
+const char *perf_pmu_name(void)
 {
-	int id = -ENODEV;
-
-	if (cpu_pmu != NULL)
-		id = cpu_pmu->id;
+	if (!cpu_pmu)
+		return NULL;
 
-	return id;
+	return cpu_pmu->pmu.name;
 }
-EXPORT_SYMBOL_GPL(armpmu_get_pmu_id);
+EXPORT_SYMBOL_GPL(perf_pmu_name);
 
 int perf_num_counters(void)
 {
@@ -760,7 +757,7 @@ init_hw_perf_events(void)
 			cpu_pmu->name, cpu_pmu->num_events);
 		cpu_pmu_init(cpu_pmu);
 		register_cpu_notifier(&pmu_cpu_notifier);
-		armpmu_register(cpu_pmu, "cpu", PERF_TYPE_RAW);
+		armpmu_register(cpu_pmu, cpu_pmu->name, PERF_TYPE_RAW);
 	} else {
 		pr_info("no hardware support available\n");
 	}
diff --git a/arch/arm/kernel/perf_event_v6.c b/arch/arm/kernel/perf_event_v6.c
index ab627a7..c90fcb2 100644
--- a/arch/arm/kernel/perf_event_v6.c
+++ b/arch/arm/kernel/perf_event_v6.c
@@ -650,7 +650,6 @@ static int armv6_map_event(struct perf_event *event)
 }
 
 static struct arm_pmu armv6pmu = {
-	.id			= ARM_PERF_PMU_ID_V6,
 	.name			= "v6",
 	.handle_irq		= armv6pmu_handle_irq,
 	.enable			= armv6pmu_enable_event,
@@ -685,7 +684,6 @@ static int armv6mpcore_map_event(struct perf_event *event)
 }
 
 static struct arm_pmu armv6mpcore_pmu = {
-	.id			= ARM_PERF_PMU_ID_V6MP,
 	.name			= "v6mpcore",
 	.handle_irq		= armv6pmu_handle_irq,
 	.enable			= armv6pmu_enable_event,
diff --git a/arch/arm/kernel/perf_event_v7.c b/arch/arm/kernel/perf_event_v7.c
index d3c5360..f04070b 100644
--- a/arch/arm/kernel/perf_event_v7.c
+++ b/arch/arm/kernel/perf_event_v7.c
@@ -1258,7 +1258,6 @@ static u32 __init armv7_read_num_pmnc_events(void)
 
 static struct arm_pmu *__init armv7_a8_pmu_init(void)
 {
-	armv7pmu.id		= ARM_PERF_PMU_ID_CA8;
 	armv7pmu.name		= "ARMv7 Cortex-A8";
 	armv7pmu.map_event	= armv7_a8_map_event;
 	armv7pmu.num_events	= armv7_read_num_pmnc_events();
@@ -1267,7 +1266,6 @@ static struct arm_pmu *__init armv7_a8_pmu_init(void)
 
 static struct arm_pmu *__init armv7_a9_pmu_init(void)
 {
-	armv7pmu.id		= ARM_PERF_PMU_ID_CA9;
 	armv7pmu.name		= "ARMv7 Cortex-A9";
 	armv7pmu.map_event	= armv7_a9_map_event;
 	armv7pmu.num_events	= armv7_read_num_pmnc_events();
@@ -1276,7 +1274,6 @@ static struct arm_pmu *__init armv7_a9_pmu_init(void)
 
 static struct arm_pmu *__init armv7_a5_pmu_init(void)
 {
-	armv7pmu.id		= ARM_PERF_PMU_ID_CA5;
 	armv7pmu.name		= "ARMv7 Cortex-A5";
 	armv7pmu.map_event	= armv7_a5_map_event;
 	armv7pmu.num_events	= armv7_read_num_pmnc_events();
@@ -1285,7 +1282,6 @@ static struct arm_pmu *__init armv7_a5_pmu_init(void)
 
 static struct arm_pmu *__init armv7_a15_pmu_init(void)
 {
-	armv7pmu.id		= ARM_PERF_PMU_ID_CA15;
 	armv7pmu.name		= "ARMv7 Cortex-A15";
 	armv7pmu.map_event	= armv7_a15_map_event;
 	armv7pmu.num_events	= armv7_read_num_pmnc_events();
@@ -1295,7 +1291,6 @@ static struct arm_pmu *__init armv7_a15_pmu_init(void)
 
 static struct arm_pmu *__init armv7_a7_pmu_init(void)
 {
-	armv7pmu.id		= ARM_PERF_PMU_ID_CA7;
 	armv7pmu.name		= "ARMv7 Cortex-A7";
 	armv7pmu.map_event	= armv7_a7_map_event;
 	armv7pmu.num_events	= armv7_read_num_pmnc_events();
diff --git a/arch/arm/kernel/perf_event_xscale.c b/arch/arm/kernel/perf_event_xscale.c
index e34e725..f759fe0 100644
--- a/arch/arm/kernel/perf_event_xscale.c
+++ b/arch/arm/kernel/perf_event_xscale.c
@@ -435,7 +435,6 @@ static int xscale_map_event(struct perf_event *event)
 }
 
 static struct arm_pmu xscale1pmu = {
-	.id		= ARM_PERF_PMU_ID_XSCALE1,
 	.name		= "xscale1",
 	.handle_irq	= xscale1pmu_handle_irq,
 	.enable		= xscale1pmu_enable_event,
@@ -803,7 +802,6 @@ xscale2pmu_write_counter(int counter, u32 val)
 }
 
 static struct arm_pmu xscale2pmu = {
-	.id		= ARM_PERF_PMU_ID_XSCALE2,
 	.name		= "xscale2",
 	.handle_irq	= xscale2pmu_handle_irq,
 	.enable		= xscale2pmu_enable_event,
diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
index 14e3826..dab711e 100644
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -907,16 +907,16 @@ long arch_ptrace(struct task_struct *child, long request,
 	return ret;
 }
 
-asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
+enum ptrace_syscall_dir {
+	PTRACE_SYSCALL_ENTER = 0,
+	PTRACE_SYSCALL_EXIT,
+};
+
+static int ptrace_syscall_trace(struct pt_regs *regs, int scno,
+				enum ptrace_syscall_dir dir)
 {
 	unsigned long ip;
 
-	if (why)
-		audit_syscall_exit(regs);
-	else
-		audit_syscall_entry(AUDIT_ARCH_ARM, scno, regs->ARM_r0,
-				    regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
-
 	if (!test_thread_flag(TIF_SYSCALL_TRACE))
 		return scno;
 
@@ -927,14 +927,28 @@ asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
 	 * IP = 0 -> entry, =1 -> exit
 	 */
 	ip = regs->ARM_ip;
-	regs->ARM_ip = why;
+	regs->ARM_ip = dir;
 
-	if (why)
+	if (dir == PTRACE_SYSCALL_EXIT)
 		tracehook_report_syscall_exit(regs, 0);
 	else if (tracehook_report_syscall_entry(regs))
 		current_thread_info()->syscall = -1;
 
 	regs->ARM_ip = ip;
-
 	return current_thread_info()->syscall;
 }
+
+asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno)
+{
+	int ret = ptrace_syscall_trace(regs, scno, PTRACE_SYSCALL_ENTER);
+	audit_syscall_entry(AUDIT_ARCH_ARM, scno, regs->ARM_r0, regs->ARM_r1,
+			    regs->ARM_r2, regs->ARM_r3);
+	return ret;
+}
+
+asmlinkage int syscall_trace_exit(struct pt_regs *regs, int scno)
+{
+	int ret = ptrace_syscall_trace(regs, scno, PTRACE_SYSCALL_EXIT);
+	audit_syscall_exit(regs);
+	return ret;
+}
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 2c7217d..aea74f5 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -179,7 +179,7 @@ void __ref cpu_die(void)
 	mb();
 
 	/* Tell __cpu_die() that this CPU is now safe to dispose of */
-	complete(&cpu_died);
+	RCU_NONIDLE(complete(&cpu_died));
 
 	/*
 	 * actual CPU shutdown procedure is at least platform (if not
diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c
index 8200dea..198b084 100644
--- a/arch/arm/kernel/topology.c
+++ b/arch/arm/kernel/topology.c
@@ -17,11 +17,190 @@
 #include <linux/percpu.h>
 #include <linux/node.h>
 #include <linux/nodemask.h>
+#include <linux/of.h>
 #include <linux/sched.h>
+#include <linux/slab.h>
 
 #include <asm/cputype.h>
 #include <asm/topology.h>
 
+/*
+ * cpu power scale management
+ */
+
+/*
+ * cpu power table
+ * This per cpu data structure describes the relative capacity of each core.
+ * On a heteregenous system, cores don't have the same computation capacity
+ * and we reflect that difference in the cpu_power field so the scheduler can
+ * take this difference into account during load balance. A per cpu structure
+ * is preferred because each CPU updates its own cpu_power field during the
+ * load balance except for idle cores. One idle core is selected to run the
+ * rebalance_domains for all idle cores and the cpu_power can be updated
+ * during this sequence.
+ */
+static DEFINE_PER_CPU(unsigned long, cpu_scale);
+
+unsigned long arch_scale_freq_power(struct sched_domain *sd, int cpu)
+{
+	return per_cpu(cpu_scale, cpu);
+}
+
+static void set_power_scale(unsigned int cpu, unsigned long power)
+{
+	per_cpu(cpu_scale, cpu) = power;
+}
+
+#ifdef CONFIG_OF
+struct cpu_efficiency {
+	const char *compatible;
+	unsigned long efficiency;
+};
+
+/*
+ * Table of relative efficiency of each processors
+ * The efficiency value must fit in 20bit and the final
+ * cpu_scale value must be in the range
+ *   0 < cpu_scale < 3*SCHED_POWER_SCALE/2
+ * in order to return at most 1 when DIV_ROUND_CLOSEST
+ * is used to compute the capacity of a CPU.
+ * Processors that are not defined in the table,
+ * use the default SCHED_POWER_SCALE value for cpu_scale.
+ */
+struct cpu_efficiency table_efficiency[] = {
+	{"arm,cortex-a15", 3891},
+	{"arm,cortex-a7",  2048},
+	{NULL, },
+};
+
+struct cpu_capacity {
+	unsigned long hwid;
+	unsigned long capacity;
+};
+
+struct cpu_capacity *cpu_capacity;
+
+unsigned long middle_capacity = 1;
+
+/*
+ * Iterate all CPUs' descriptor in DT and compute the efficiency
+ * (as per table_efficiency). Also calculate a middle efficiency
+ * as close as possible to  (max{eff_i} - min{eff_i}) / 2
+ * This is later used to scale the cpu_power field such that an
+ * 'average' CPU is of middle power. Also see the comments near
+ * table_efficiency[] and update_cpu_power().
+ */
+static void __init parse_dt_topology(void)
+{
+	struct cpu_efficiency *cpu_eff;
+	struct device_node *cn = NULL;
+	unsigned long min_capacity = (unsigned long)(-1);
+	unsigned long max_capacity = 0;
+	unsigned long capacity = 0;
+	int alloc_size, cpu = 0;
+
+	alloc_size = nr_cpu_ids * sizeof(struct cpu_capacity);
+	cpu_capacity = (struct cpu_capacity *)kzalloc(alloc_size, GFP_NOWAIT);
+
+	while ((cn = of_find_node_by_type(cn, "cpu"))) {
+		const u32 *rate, *reg;
+		int len;
+
+		if (cpu >= num_possible_cpus())
+			break;
+
+		for (cpu_eff = table_efficiency; cpu_eff->compatible; cpu_eff++)
+			if (of_device_is_compatible(cn, cpu_eff->compatible))
+				break;
+
+		if (cpu_eff->compatible == NULL)
+			continue;
+
+		rate = of_get_property(cn, "clock-frequency", &len);
+		if (!rate || len != 4) {
+			pr_err("%s missing clock-frequency property\n",
+				cn->full_name);
+			continue;
+		}
+
+		reg = of_get_property(cn, "reg", &len);
+		if (!reg || len != 4) {
+			pr_err("%s missing reg property\n", cn->full_name);
+			continue;
+		}
+
+		capacity = ((be32_to_cpup(rate)) >> 20) * cpu_eff->efficiency;
+
+		/* Save min capacity of the system */
+		if (capacity < min_capacity)
+			min_capacity = capacity;
+
+		/* Save max capacity of the system */
+		if (capacity > max_capacity)
+			max_capacity = capacity;
+
+		cpu_capacity[cpu].capacity = capacity;
+		cpu_capacity[cpu++].hwid = be32_to_cpup(reg);
+	}
+
+	if (cpu < num_possible_cpus())
+		cpu_capacity[cpu].hwid = (unsigned long)(-1);
+
+	/* If min and max capacities are equals, we bypass the update of the
+	 * cpu_scale because all CPUs have the same capacity. Otherwise, we
+	 * compute a middle_capacity factor that will ensure that the capacity
+	 * of an 'average' CPU of the system will be as close as possible to
+	 * SCHED_POWER_SCALE, which is the default value, but with the
+	 * constraint explained near table_efficiency[].
+	 */
+	if (min_capacity == max_capacity)
+		cpu_capacity[0].hwid = (unsigned long)(-1);
+	else if (4*max_capacity < (3*(max_capacity + min_capacity)))
+		middle_capacity = (min_capacity + max_capacity)
+				>> (SCHED_POWER_SHIFT+1);
+	else
+		middle_capacity = ((max_capacity / 3)
+				>> (SCHED_POWER_SHIFT-1)) + 1;
+
+}
+
+/*
+ * Look for a customed capacity of a CPU in the cpu_capacity table during the
+ * boot. The update of all CPUs is in O(n^2) for heteregeneous system but the
+ * function returns directly for SMP system.
+ */
+void update_cpu_power(unsigned int cpu, unsigned long hwid)
+{
+	unsigned int idx = 0;
+
+	/* look for the cpu's hwid in the cpu capacity table */
+	for (idx = 0; idx < num_possible_cpus(); idx++) {
+		if (cpu_capacity[idx].hwid == hwid)
+			break;
+
+		if (cpu_capacity[idx].hwid == -1)
+			return;
+	}
+
+	if (idx == num_possible_cpus())
+		return;
+
+	set_power_scale(cpu, cpu_capacity[idx].capacity / middle_capacity);
+
+	printk(KERN_INFO "CPU%u: update cpu_power %lu\n",
+		cpu, arch_scale_freq_power(NULL, cpu));
+}
+
+#else
+static inline void parse_dt_topology(void) {}
+static inline void update_cpu_power(unsigned int cpuid, unsigned int mpidr) {}
+#endif
+
+
+/*
+ * cpu topology management
+ */
+
 #define MPIDR_SMP_BITMASK (0x3 << 30)
 #define MPIDR_SMP_VALUE (0x2 << 30)
 
@@ -31,6 +210,7 @@
  * These masks reflect the current use of the affinity levels.
  * The affinity level can be up to 16 bits according to ARM ARM
  */
+#define MPIDR_HWID_BITMASK 0xFFFFFF
 
 #define MPIDR_LEVEL0_MASK 0x3
 #define MPIDR_LEVEL0_SHIFT 0
@@ -41,6 +221,9 @@
 #define MPIDR_LEVEL2_MASK 0xFF
 #define MPIDR_LEVEL2_SHIFT 16
 
+/*
+ * cpu topology table
+ */
 struct cputopo_arm cpu_topology[NR_CPUS];
 
 const struct cpumask *cpu_coregroup_mask(int cpu)
@@ -48,6 +231,32 @@ const struct cpumask *cpu_coregroup_mask(int cpu)
 	return &cpu_topology[cpu].core_sibling;
 }
 
+void update_siblings_masks(unsigned int cpuid)
+{
+	struct cputopo_arm *cpu_topo, *cpuid_topo = &cpu_topology[cpuid];
+	int cpu;
+
+	/* update core and thread sibling masks */
+	for_each_possible_cpu(cpu) {
+		cpu_topo = &cpu_topology[cpu];
+
+		if (cpuid_topo->socket_id != cpu_topo->socket_id)
+			continue;
+
+		cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
+		if (cpu != cpuid)
+			cpumask_set_cpu(cpu, &cpuid_topo->core_sibling);
+
+		if (cpuid_topo->core_id != cpu_topo->core_id)
+			continue;
+
+		cpumask_set_cpu(cpuid, &cpu_topo->thread_sibling);
+		if (cpu != cpuid)
+			cpumask_set_cpu(cpu, &cpuid_topo->thread_sibling);
+	}
+	smp_wmb();
+}
+
 /*
  * store_cpu_topology is called at boot when only one cpu is running
  * and with the mutex cpu_hotplug.lock locked, when several cpus have booted,
@@ -57,7 +266,6 @@ void store_cpu_topology(unsigned int cpuid)
 {
 	struct cputopo_arm *cpuid_topo = &cpu_topology[cpuid];
 	unsigned int mpidr;
-	unsigned int cpu;
 
 	/* If the cpu topology has been already set, just return */
 	if (cpuid_topo->core_id != -1)
@@ -99,26 +307,9 @@ void store_cpu_topology(unsigned int cpuid)
 		cpuid_topo->socket_id = -1;
 	}
 
-	/* update core and thread sibling masks */
-	for_each_possible_cpu(cpu) {
-		struct cputopo_arm *cpu_topo = &cpu_topology[cpu];
-
-		if (cpuid_topo->socket_id == cpu_topo->socket_id) {
-			cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
-			if (cpu != cpuid)
-				cpumask_set_cpu(cpu,
-					&cpuid_topo->core_sibling);
-
-			if (cpuid_topo->core_id == cpu_topo->core_id) {
-				cpumask_set_cpu(cpuid,
-					&cpu_topo->thread_sibling);
-				if (cpu != cpuid)
-					cpumask_set_cpu(cpu,
-						&cpuid_topo->thread_sibling);
-			}
-		}
-	}
-	smp_wmb();
+	update_siblings_masks(cpuid);
+
+	update_cpu_power(cpuid, mpidr & MPIDR_HWID_BITMASK);
 
 	printk(KERN_INFO "CPU%u: thread %d, cpu %d, socket %d, mpidr %x\n",
 		cpuid, cpu_topology[cpuid].thread_id,
@@ -134,7 +325,7 @@ void init_cpu_topology(void)
 {
 	unsigned int cpu;
 
-	/* init core mask */
+	/* init core mask and power*/
 	for_each_possible_cpu(cpu) {
 		struct cputopo_arm *cpu_topo = &(cpu_topology[cpu]);
 
@@ -143,6 +334,10 @@ void init_cpu_topology(void)
 		cpu_topo->socket_id = -1;
 		cpumask_clear(&cpu_topo->core_sibling);
 		cpumask_clear(&cpu_topo->thread_sibling);
+
+		set_power_scale(cpu, SCHED_POWER_SCALE);
 	}
 	smp_wmb();
+
+	parse_dt_topology();
 }
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 3647170..8b97d73 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -233,9 +233,9 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
 #define S_ISA " ARM"
 #endif
 
-static int __die(const char *str, int err, struct thread_info *thread, struct pt_regs *regs)
+static int __die(const char *str, int err, struct pt_regs *regs)
 {
-	struct task_struct *tsk = thread->task;
+	struct task_struct *tsk = current;
 	static int die_counter;
 	int ret;
 
@@ -245,12 +245,12 @@ static int __die(const char *str, int err, struct thread_info *thread, struct pt
 	/* trap and error numbers are mostly meaningless on ARM */
 	ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
 	if (ret == NOTIFY_STOP)
-		return ret;
+		return 1;
 
 	print_modules();
 	__show_regs(regs);
 	printk(KERN_EMERG "Process %.*s (pid: %d, stack limit = 0x%p)\n",
-		TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
+		TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk));
 
 	if (!user_mode(regs) || in_interrupt()) {
 		dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
@@ -259,45 +259,77 @@ static int __die(const char *str, int err, struct thread_info *thread, struct pt
 		dump_instr(KERN_EMERG, regs);
 	}
 
-	return ret;
+	return 0;
 }
 
-static DEFINE_RAW_SPINLOCK(die_lock);
+static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
+static int die_owner = -1;
+static unsigned int die_nest_count;
 
-/*
- * This function is protected against re-entrancy.
- */
-void die(const char *str, struct pt_regs *regs, int err)
+static unsigned long oops_begin(void)
 {
-	struct thread_info *thread = current_thread_info();
-	int ret;
-	enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
+	int cpu;
+	unsigned long flags;
 
 	oops_enter();
 
-	raw_spin_lock_irq(&die_lock);
+	/* racy, but better than risking deadlock. */
+	raw_local_irq_save(flags);
+	cpu = smp_processor_id();
+	if (!arch_spin_trylock(&die_lock)) {
+		if (cpu == die_owner)
+			/* nested oops. should stop eventually */;
+		else
+			arch_spin_lock(&die_lock);
+	}
+	die_nest_count++;
+	die_owner = cpu;
 	console_verbose();
 	bust_spinlocks(1);
-	if (!user_mode(regs))
-		bug_type = report_bug(regs->ARM_pc, regs);
-	if (bug_type != BUG_TRAP_TYPE_NONE)
-		str = "Oops - BUG";
-	ret = __die(str, err, thread, regs);
+	return flags;
+}
 
-	if (regs && kexec_should_crash(thread->task))
+static void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
+{
+	if (regs && kexec_should_crash(current))
 		crash_kexec(regs);
 
 	bust_spinlocks(0);
+	die_owner = -1;
 	add_taint(TAINT_DIE);
-	raw_spin_unlock_irq(&die_lock);
+	die_nest_count--;
+	if (!die_nest_count)
+		/* Nest count reaches zero, release the lock. */
+		arch_spin_unlock(&die_lock);
+	raw_local_irq_restore(flags);
 	oops_exit();
 
 	if (in_interrupt())
 		panic("Fatal exception in interrupt");
 	if (panic_on_oops)
 		panic("Fatal exception");
-	if (ret != NOTIFY_STOP)
-		do_exit(SIGSEGV);
+	if (signr)
+		do_exit(signr);
+}
+
+/*
+ * This function is protected against re-entrancy.
+ */
+void die(const char *str, struct pt_regs *regs, int err)
+{
+	enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
+	unsigned long flags = oops_begin();
+	int sig = SIGSEGV;
+
+	if (!user_mode(regs))
+		bug_type = report_bug(regs->ARM_pc, regs);
+	if (bug_type != BUG_TRAP_TYPE_NONE)
+		str = "Oops - BUG";
+
+	if (__die(str, err, regs))
+		sig = 0;
+
+	oops_end(flags, regs, sig);
 }
 
 void arm_notify_die(const char *str, struct pt_regs *regs,