+ platform_device_unregister(oprofile_pdev);
+ platform_driver_unregister(&oprofile_driver);
+}
+#else
+static int __init init_driverfs(void) { return 0; }
+#define exit_driverfs() do { } while (0)
+#endif /* CONFIG_PM */
+
+static int report_trace(struct stackframe *frame, void *d)
+{
+ unsigned int *depth = d;
+
+ if (*depth) {
+ oprofile_add_trace(frame->pc);
+ (*depth)--;
+ }
+
+ return *depth == 0;
+}
+
+/*
+ * The registers we're interested in are at the end of the variable
+ * length saved register structure. The fp points at the end of this
+ * structure so the address of this struct is:
+ * (struct frame_tail *)(xxx->fp)-1
+ */
+struct frame_tail {
+ struct frame_tail *fp;
+ unsigned long sp;
+ unsigned long lr;
+} __attribute__((packed));
+
+static struct frame_tail* user_backtrace(struct frame_tail *tail)
+{
+ struct frame_tail buftail[2];
+
+ /* Also check accessibility of one struct frame_tail beyond */
+ if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
+ return NULL;
+ if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail)))
+ return NULL;
+
+ oprofile_add_trace(buftail[0].lr);
+
+ /* frame pointers should strictly progress back up the stack
+ * (towards higher addresses) */
+ if (tail >= buftail[0].fp)
+ return NULL;
+
+ return buftail[0].fp-1;
+}
+
+static void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
+{
+ struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1;
+
+ if (!user_mode(regs)) {
+ struct stackframe frame;
+ frame.fp = regs->ARM_fp;
+ frame.sp = regs->ARM_sp;
+ frame.lr = regs->ARM_lr;
+ frame.pc = regs->ARM_pc;
+ walk_stackframe(&frame, report_trace, &depth);
+ return;
+ }
+
+ while (depth-- && tail && !((unsigned long) tail & 3))
+ tail = user_backtrace(tail);
+}
+
+int __init oprofile_arch_init(struct oprofile_operations *ops)
+{
+ int cpu, ret = 0;
+
+ perf_num_counters = armpmu_get_max_events();
+
+ counter_config = kcalloc(perf_num_counters,
+ sizeof(struct op_counter_config), GFP_KERNEL);
+
+ if (!counter_config) {
+ pr_info("oprofile: failed to allocate %d "
+ "counters\n", perf_num_counters);
+ return -ENOMEM;
+ }
+
+ ret = init_driverfs();
+ if (ret) {
+ kfree(counter_config);
+ return ret;
+ }
+
+ for_each_possible_cpu(cpu) {
+ perf_events[cpu] = kcalloc(perf_num_counters,
+ sizeof(struct perf_event *), GFP_KERNEL);
+ if (!perf_events[cpu]) {
+ pr_info("oprofile: failed to allocate %d perf events "
+ "for cpu %d\n", perf_num_counters, cpu);
+ while (--cpu >= 0)
+ kfree(perf_events[cpu]);
+ return -ENOMEM;
+ }