oprofile, x86: Convert memory allocation to static array

On -rt, allocators don't work from atomic context any more,
and the maximum size of the array is known at compile time.

Call trace on a -rt kernel:

oprofile: using NMI interrupt.
BUG: sleeping function called from invalid context at kernel/rtmutex.c:645
in_atomic(): 1, irqs_disabled(): 1, pid: 0, name: kworker/0:1
Pid: 0, comm: kworker/0:1 Tainted: G         C  3.0.0-rt3-patser+ #39
Call Trace:
 <IRQ>  [<ffffffff8103fc0a>] __might_sleep+0xca/0xf0
 [<ffffffff8160d424>] rt_spin_lock+0x24/0x40
 [<ffffffff811476c7>] __kmalloc+0xc7/0x370
 [<ffffffffa0275c85>] ? ppro_setup_ctrs+0x215/0x260 [oprofile]
 [<ffffffffa0273de0>] ? oprofile_cpu_notifier+0x60/0x60 [oprofile]
 [<ffffffffa0275c85>] ppro_setup_ctrs+0x215/0x260 [oprofile]
 [<ffffffffa0273de0>] ? oprofile_cpu_notifier+0x60/0x60 [oprofile]
 [<ffffffffa0273de0>] ? oprofile_cpu_notifier+0x60/0x60 [oprofile]
 [<ffffffffa0273ea4>] nmi_cpu_setup+0xc4/0x110 [oprofile]
 [<ffffffff81094455>] generic_smp_call_function_interrupt+0x95/0x190
 [<ffffffff8101df77>] smp_call_function_interrupt+0x27/0x40
 [<ffffffff81615093>] call_function_interrupt+0x13/0x20
 <EOI>  [<ffffffff8131d0c4>] ? plist_check_head+0x54/0xc0
 [<ffffffff81371fe8>] ? intel_idle+0xc8/0x120
 [<ffffffff81371fc7>] ? intel_idle+0xa7/0x120
 [<ffffffff814a57b0>] cpuidle_idle_call+0xb0/0x230
 [<ffffffff810011db>] cpu_idle+0x8b/0xe0
 [<ffffffff815fc82f>] start_secondary+0x1d3/0x1d8

Signed-off-by: Maarten Lankhorst <m.b.lankhorst@gmail.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>

arch/x86/oprofile/op_model_ppro.c

@@ -28,7 +28,7 @@ static int counter_width = 32;
 
 #define MSR_PPRO_EVENTSEL_RESERVED	((0xFFFFFFFFULL<<32)|(1ULL<<21))
 
-static u64 *reset_value;
+static u64 reset_value[OP_MAX_COUNTER];
 
 static void ppro_shutdown(struct op_msrs const * const msrs)
 {
@@ -40,10 +40,6 @@ static void ppro_shutdown(struct op_msrs const * const msrs)
 		release_perfctr_nmi(MSR_P6_PERFCTR0 + i);
 		release_evntsel_nmi(MSR_P6_EVNTSEL0 + i);
 	}
-	if (reset_value) {
-		kfree(reset_value);
-		reset_value = NULL;
-	}
 }
 
 static int ppro_fill_in_addresses(struct op_msrs * const msrs)
@@ -79,13 +75,6 @@ static void ppro_setup_ctrs(struct op_x86_model_spec const *model,
 	u64 val;
 	int i;
 
-	if (!reset_value) {
-		reset_value = kzalloc(sizeof(reset_value[0]) * num_counters,
-					GFP_ATOMIC);
-		if (!reset_value)
-			return;
-	}
-
 	if (cpu_has_arch_perfmon) {
 		union cpuid10_eax eax;
 		eax.full = cpuid_eax(0xa);
@@ -141,13 +130,6 @@ static int ppro_check_ctrs(struct pt_regs * const regs,
 	u64 val;
 	int i;
 
-	/*
-	 * This can happen if perf counters are in use when
-	 * we steal the die notifier NMI.
-	 */
-	if (unlikely(!reset_value))
-		goto out;
-
 	for (i = 0; i < num_counters; ++i) {
 		if (!reset_value[i])
 			continue;
@@ -179,8 +161,6 @@ static void ppro_start(struct op_msrs const * const msrs)
 	u64 val;
 	int i;
 
-	if (!reset_value)
-		return;
 	for (i = 0; i < num_counters; ++i) {
 		if (reset_value[i]) {
 			rdmsrl(msrs->controls[i].addr, val);
@@ -196,8 +176,6 @@ static void ppro_stop(struct op_msrs const * const msrs)
 	u64 val;
 	int i;
 
-	if (!reset_value)
-		return;
 	for (i = 0; i < num_counters; ++i) {
 		if (!reset_value[i])
 			continue;