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authorHelge Deller <deller@gmx.de>2016-04-13 22:27:22 +0200
committerHelge Deller <deller@gmx.de>2016-04-14 17:47:19 +0200
commit366dd4ea9d5f0eb78fdf4982d76506f99480ec0a (patch)
treea1540803a33b13685a1fe2e3fa8af13bc2e7f018 /arch/parisc/kernel/ftrace.c
parentb562e44f507e863c6792946e4e1b1449fbbac85d (diff)
download96b-common-366dd4ea9d5f0eb78fdf4982d76506f99480ec0a.tar.gz
parisc: Fix ftrace function tracer
Fix the FTRACE function tracer for 32- and 64-bit kernel. The former code was horribly broken. Reimplement most coding in assembly and utilize optimizations, e.g. put mcount() and ftrace_stub() into one L1 cacheline. Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'arch/parisc/kernel/ftrace.c')
-rw-r--r--arch/parisc/kernel/ftrace.c146
1 files changed, 23 insertions, 123 deletions
diff --git a/arch/parisc/kernel/ftrace.c b/arch/parisc/kernel/ftrace.c
index 559d400f9385..b13f9ec6f294 100644
--- a/arch/parisc/kernel/ftrace.c
+++ b/arch/parisc/kernel/ftrace.c
@@ -1,6 +1,6 @@
/*
* Code for tracing calls in Linux kernel.
- * Copyright (C) 2009 Helge Deller <deller@gmx.de>
+ * Copyright (C) 2009-2016 Helge Deller <deller@gmx.de>
*
* based on code for x86 which is:
* Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
@@ -13,104 +13,21 @@
#include <linux/init.h>
#include <linux/ftrace.h>
+#include <asm/assembly.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 = local_clock();
- 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)
+static void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
{
unsigned long old;
- unsigned long long calltime;
struct ftrace_graph_ent trace;
+ extern int parisc_return_to_handler;
if (unlikely(ftrace_graph_is_dead()))
return;
@@ -119,64 +36,47 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
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 = local_clock();
+ trace.func = self_addr;
+ trace.depth = current->curr_ret_stack + 1;
- if (push_return_trace(old, calltime,
- self_addr, &trace.depth) == -EBUSY) {
- *parent = old;
+ /* Only trace if the calling function expects to */
+ if (!ftrace_graph_entry(&trace))
return;
- }
- trace.func = self_addr;
+ if (ftrace_push_return_trace(old, self_addr, &trace.depth,
+ 0 ) == -EBUSY)
+ return;
- /* Only trace if the calling function expects to */
- if (!ftrace_graph_entry(&trace)) {
- current->curr_ret_stack--;
- *parent = old;
- }
+ /* activate parisc_return_to_handler() as return point */
+ *parent = (unsigned long) &parisc_return_to_handler;
}
-
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
-
-void ftrace_function_trampoline(unsigned long parent,
+void notrace ftrace_function_trampoline(unsigned long parent,
unsigned long self_addr,
unsigned long org_sp_gr3)
{
- extern ftrace_func_t ftrace_trace_function;
+ extern ftrace_func_t ftrace_trace_function; /* depends on CONFIG_DYNAMIC_FTRACE */
+ extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
if (ftrace_trace_function != ftrace_stub) {
- ftrace_trace_function(parent, self_addr);
+ /* struct ftrace_ops *op, struct pt_regs *regs); */
+ ftrace_trace_function(parent, self_addr, NULL, NULL);
return;
}
+
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- if (ftrace_graph_entry && ftrace_graph_return) {
- unsigned long sp;
+ if (ftrace_graph_return != (trace_func_graph_ret_t) ftrace_stub ||
+ ftrace_graph_entry != ftrace_graph_entry_stub) {
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;
+ parent_rp = (unsigned long *) (org_sp_gr3 - RP_OFFSET);
/* sanity check: parent_rp should hold parent */
if (*parent_rp != parent)
return;
-
+
prepare_ftrace_return(parent_rp, self_addr);
return;
}