Merge branch 'omap-pool'

[linux-2.6-omap-h63xx.git] / arch / parisc / kernel / ftrace.c

diff --git a/arch/parisc/kernel/ftrace.c b/arch/parisc/kernel/ftrace.c
new file mode 100644 (file)
index 0000000..9877372
--- /dev/null
+++ b/arch/parisc/kernel/ftrace.c
@@ -0,0 +1,185 @@
+/*
+ * Code for tracing calls in Linux kernel.
+ * Copyright (C) 2009 Helge Deller <deller@gmx.de>
+ *
+ * based on code for x86 which is:
+ * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
+ *
+ * future possible enhancements:
+ *     - add CONFIG_DYNAMIC_FTRACE
+ *     - add CONFIG_STACK_TRACER
+ */
+
+#include <linux/init.h>
+#include <linux/ftrace.h>
+
+#include <asm/sections.h>
+#include <asm/ftrace.h>
+
+
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+/* Add a function return address to the trace stack on thread info.*/
+static int push_return_trace(unsigned long ret, unsigned long long time,
+                               unsigned long func, int *depth)
+{
+       int index;
+
+       if (!current->ret_stack)
+               return -EBUSY;
+
+       /* The return trace stack is full */
+       if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
+               atomic_inc(&current->trace_overrun);
+               return -EBUSY;
+       }
+
+       index = ++current->curr_ret_stack;
+       barrier();
+       current->ret_stack[index].ret = ret;
+       current->ret_stack[index].func = func;
+       current->ret_stack[index].calltime = time;
+       *depth = index;
+
+       return 0;
+}
+
+/* Retrieve a function return address to the trace stack on thread info.*/
+static void pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
+{
+       int index;
+
+       index = current->curr_ret_stack;
+
+       if (unlikely(index < 0)) {
+               ftrace_graph_stop();
+               WARN_ON(1);
+               /* Might as well panic, otherwise we have no where to go */
+               *ret = (unsigned long)
+                       dereference_function_descriptor(&panic);
+               return;
+       }
+
+       *ret = current->ret_stack[index].ret;
+       trace->func = current->ret_stack[index].func;
+       trace->calltime = current->ret_stack[index].calltime;
+       trace->overrun = atomic_read(&current->trace_overrun);
+       trace->depth = index;
+       barrier();
+       current->curr_ret_stack--;
+
+}
+
+/*
+ * Send the trace to the ring-buffer.
+ * @return the original return address.
+ */
+unsigned long ftrace_return_to_handler(unsigned long retval0,
+                                      unsigned long retval1)
+{
+       struct ftrace_graph_ret trace;
+       unsigned long ret;
+
+       pop_return_trace(&trace, &ret);
+       trace.rettime = cpu_clock(raw_smp_processor_id());
+       ftrace_graph_return(&trace);
+
+       if (unlikely(!ret)) {
+               ftrace_graph_stop();
+               WARN_ON(1);
+               /* Might as well panic. What else to do? */
+               ret = (unsigned long)
+                       dereference_function_descriptor(&panic);
+       }
+
+       /* HACK: we hand over the old functions' return values
+          in %r23 and %r24. Assembly in entry.S will take care
+          and move those to their final registers %ret0 and %ret1 */
+       asm( "copy %0, %%r23 \n\t"
+            "copy %1, %%r24 \n" : : "r" (retval0), "r" (retval1) );
+
+       return ret;
+}
+
+/*
+ * Hook the return address and push it in the stack of return addrs
+ * in current thread info.
+ */
+void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
+{
+       unsigned long old;
+       unsigned long long calltime;
+       struct ftrace_graph_ent trace;
+
+       if (unlikely(atomic_read(&current->tracing_graph_pause)))
+               return;
+
+       old = *parent;
+       *parent = (unsigned long)
+                 dereference_function_descriptor(&return_to_handler);
+
+       if (unlikely(!__kernel_text_address(old))) {
+               ftrace_graph_stop();
+               *parent = old;
+               WARN_ON(1);
+               return;
+       }
+
+       calltime = cpu_clock(raw_smp_processor_id());
+
+       if (push_return_trace(old, calltime,
+                               self_addr, &trace.depth) == -EBUSY) {
+               *parent = old;
+               return;
+       }
+
+       trace.func = self_addr;
+
+       /* Only trace if the calling function expects to */
+       if (!ftrace_graph_entry(&trace)) {
+               current->curr_ret_stack--;
+               *parent = old;
+       }
+}
+
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+
+void ftrace_function_trampoline(unsigned long parent,
+                               unsigned long self_addr,
+                               unsigned long org_sp_gr3)
+{
+       extern ftrace_func_t ftrace_trace_function;
+
+       if (function_trace_stop)
+               return;
+
+       if (ftrace_trace_function != ftrace_stub) {
+               ftrace_trace_function(parent, self_addr);
+               return;
+       }
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+       if (ftrace_graph_entry && ftrace_graph_return) {
+               unsigned long sp;
+               unsigned long *parent_rp;
+
+                asm volatile ("copy %%r30, %0" : "=r"(sp));
+               /* sanity check: is stack pointer which we got from
+                  assembler function in entry.S in a reasonable
+                  range compared to current stack pointer? */
+               if ((sp - org_sp_gr3) > 0x400)
+                       return;
+
+               /* calculate pointer to %rp in stack */
+               parent_rp = (unsigned long *) org_sp_gr3 - 0x10;
+               /* sanity check: parent_rp should hold parent */
+               if (*parent_rp != parent)
+                       return;
+               
+               prepare_ftrace_return(parent_rp, self_addr);
+               return;
+       }
+#endif
+}
+