Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git…

…/benh/powerpc * 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: powerpc: Fix unpaired __trace_hcall_entry and __trace_hcall_exit powerpc: Fix RCU idle and hcall tracing
jledet · Jan 14, 2012 · 8e63dd6 · 8e63dd6
2 parents f88609a + ebb7f61
commit 8e63dd6
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Showing 3 changed files with 14 additions and 15 deletions.
diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c
@@ -50,12 +50,6 @@ static int __init powersave_off(char *arg)
 }
 __setup("powersave=off", powersave_off);
 
-#if defined(CONFIG_PPC_PSERIES) && defined(CONFIG_TRACEPOINTS)
-static const bool idle_uses_rcu = 1;
-#else
-static const bool idle_uses_rcu;
-#endif
-
 /*
  * The body of the idle task.
  */
@@ -67,8 +61,7 @@ void cpu_idle(void)
 	set_thread_flag(TIF_POLLING_NRFLAG);
 	while (1) {
 		tick_nohz_idle_enter();
-		if (!idle_uses_rcu)
-			rcu_idle_enter();
+		rcu_idle_enter();
 
 		while (!need_resched() && !cpu_should_die()) {
 			ppc64_runlatch_off();
@@ -106,8 +99,7 @@ void cpu_idle(void)
 
 		HMT_medium();
 		ppc64_runlatch_on();
-		if (!idle_uses_rcu)
-			rcu_idle_exit();
+		rcu_idle_exit();
 		tick_nohz_idle_exit();
 		preempt_enable_no_resched();
 		if (cpu_should_die())

diff --git a/arch/powerpc/platforms/pseries/hvCall.S b/arch/powerpc/platforms/pseries/hvCall.S
@@ -36,6 +36,7 @@ BEGIN_FTR_SECTION;						\
 	b	1f;						\
 END_FTR_SECTION(0, 1);						\
 	ld      r12,hcall_tracepoint_refcount@toc(r2);		\
+	std	r12,32(r1);					\
 	cmpdi	r12,0;						\
 	beq+	1f;						\
 	mflr	r0;						\
@@ -74,7 +75,7 @@ END_FTR_SECTION(0, 1);						\
 BEGIN_FTR_SECTION;						\
 	b	1f;						\
 END_FTR_SECTION(0, 1);						\
-	ld      r12,hcall_tracepoint_refcount@toc(r2);		\
+	ld      r12,32(r1);					\
 	cmpdi	r12,0;						\
 	beq+	1f;						\
 	mflr	r0;						\

diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
@@ -546,6 +546,13 @@ void __trace_hcall_entry(unsigned long opcode, unsigned long *args)
 	unsigned long flags;
 	unsigned int *depth;
 
+	/*
+	 * We cannot call tracepoints inside RCU idle regions which
+	 * means we must not trace H_CEDE.
+	 */
+	if (opcode == H_CEDE)
+		return;
+
 	local_irq_save(flags);
 
 	depth = &__get_cpu_var(hcall_trace_depth);
@@ -556,8 +563,6 @@ void __trace_hcall_entry(unsigned long opcode, unsigned long *args)
 	(*depth)++;
 	preempt_disable();
 	trace_hcall_entry(opcode, args);
-	if (opcode == H_CEDE)
-		rcu_idle_enter();
 	(*depth)--;
 
 out:
@@ -570,6 +575,9 @@ void __trace_hcall_exit(long opcode, unsigned long retval,
 	unsigned long flags;
 	unsigned int *depth;
 
+	if (opcode == H_CEDE)
+		return;
+
 	local_irq_save(flags);
 
 	depth = &__get_cpu_var(hcall_trace_depth);
@@ -578,8 +586,6 @@ void __trace_hcall_exit(long opcode, unsigned long retval,
 		goto out;
 
 	(*depth)++;
-	if (opcode == H_CEDE)
-		rcu_idle_exit();
 	trace_hcall_exit(opcode, retval, retbuf);
 	preempt_enable();
 	(*depth)--;