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>

1 files changed, 1 insertions, 23 deletions

diff --git a/arch/x86/oprofile/op_model_ppro.c b/arch/x86/oprofile/op_model_ppro.c
index 94b745045e45..608874b70cf4 100644
--- a/arch/x86/oprofile/op_model_ppro.c
+++ b/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;