diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
index 01a134141216..521e15bc6401 100644
--- a/arch/arm/Kconfig.debug
+++ b/arch/arm/Kconfig.debug
@@ -369,4 +369,13 @@ config ARM_KPROBES_TEST
 	help
 	  Perform tests of kprobes API and instruction set simulation.
 
+config PID_IN_CONTEXTIDR
+	bool "Write the current PID to the CONTEXTIDR register"
+	depends on CPU_COPY_V6
+	help
+	  Enabling this option causes the kernel to write the current PID to
+	  the PROCID field of the CONTEXTIDR register, at the expense of some
+	  additional instructions during context switch. Say Y here only if you
+	  are planning to use hardware trace tools with this kernel.
+
 endmenu
diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c
index 806cc4f63516..119bc52ab93e 100644
--- a/arch/arm/mm/context.c
+++ b/arch/arm/mm/context.c
@@ -14,6 +14,7 @@
 #include <linux/percpu.h>
 
 #include <asm/mmu_context.h>
+#include <asm/thread_notify.h>
 #include <asm/tlbflush.h>
 
 static DEFINE_RAW_SPINLOCK(cpu_asid_lock);
@@ -48,6 +49,40 @@ void cpu_set_reserved_ttbr0(void)
 }
 #endif
 
+#ifdef CONFIG_PID_IN_CONTEXTIDR
+static int contextidr_notifier(struct notifier_block *unused, unsigned long cmd,
+			       void *t)
+{
+	u32 contextidr;
+	pid_t pid;
+	struct thread_info *thread = t;
+
+	if (cmd != THREAD_NOTIFY_SWITCH)
+		return NOTIFY_DONE;
+
+	pid = task_pid_nr(thread->task) << ASID_BITS;
+	asm volatile(
+	"	mrc	p15, 0, %0, c13, c0, 1\n"
+	"	bfi	%1, %0, #0, %2\n"
+	"	mcr	p15, 0, %1, c13, c0, 1\n"
+	: "=r" (contextidr), "+r" (pid)
+	: "I" (ASID_BITS));
+	isb();
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block contextidr_notifier_block = {
+	.notifier_call = contextidr_notifier,
+};
+
+static int __init contextidr_notifier_init(void)
+{
+	return thread_register_notifier(&contextidr_notifier_block);
+}
+arch_initcall(contextidr_notifier_init);
+#endif
+
 /*
  * We fork()ed a process, and we need a new context for the child
  * to run in.
diff --git a/arch/arm/mm/proc-v6.S b/arch/arm/mm/proc-v6.S
index 5900cd520e84..86b8b480634f 100644
--- a/arch/arm/mm/proc-v6.S
+++ b/arch/arm/mm/proc-v6.S
@@ -107,6 +107,12 @@ ENTRY(cpu_v6_switch_mm)
 	mcr	p15, 0, r2, c7, c5, 6		@ flush BTAC/BTB
 	mcr	p15, 0, r2, c7, c10, 4		@ drain write buffer
 	mcr	p15, 0, r0, c2, c0, 0		@ set TTB 0
+#ifdef CONFIG_PID_IN_CONTEXTIDR
+	mrc	p15, 0, r2, c13, c0, 1		@ read current context ID
+	bic	r2, r2, #0xff			@ extract the PID
+	and	r1, r1, #0xff
+	orr	r1, r1, r2			@ insert into new context ID
+#endif
 	mcr	p15, 0, r1, c13, c0, 1		@ set context ID
 #endif
 	mov	pc, lr
diff --git a/arch/arm/mm/proc-v7-2level.S b/arch/arm/mm/proc-v7-2level.S
index 42ac069c8012..fd045e706390 100644
--- a/arch/arm/mm/proc-v7-2level.S
+++ b/arch/arm/mm/proc-v7-2level.S
@@ -46,6 +46,11 @@ ENTRY(cpu_v7_switch_mm)
 #ifdef CONFIG_ARM_ERRATA_430973
 	mcr	p15, 0, r2, c7, c5, 6		@ flush BTAC/BTB
 #endif
+#ifdef CONFIG_PID_IN_CONTEXTIDR
+	mrc	p15, 0, r2, c13, c0, 1		@ read current context ID
+	lsr	r2, r2, #8			@ extract the PID
+	bfi	r1, r2, #8, #24			@ insert into new context ID
+#endif
 #ifdef CONFIG_ARM_ERRATA_754322
 	dsb
 #endif