4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
commit 8712b27c5723c26400a2b350faf1d6d9fd7ffaad upstream.
The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().
Have MIPS use the new code, and remove the shadow stack management as well as
having to set up the trace structure.
This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Paul Burton <paul.burton@xxxxxxxx>
Cc: James Hogan <jhogan@xxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxx
Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/mips/kernel/ftrace.c | 14 ++------------
1 file changed, 2 insertions(+), 12 deletions(-)
--- a/arch/mips/kernel/ftrace.c
+++ b/arch/mips/kernel/ftrace.c
@@ -322,7 +322,6 @@ void prepare_ftrace_return(unsigned long
unsigned long fp)
{
unsigned long old_parent_ra;
- struct ftrace_graph_ent trace;
unsigned long return_hooker = (unsigned long)
&return_to_handler;
int faulted, insns;
@@ -369,12 +368,6 @@ void prepare_ftrace_return(unsigned long
if (unlikely(faulted))
goto out;
- if (ftrace_push_return_trace(old_parent_ra, self_ra, &trace.depth, fp,
- NULL) == -EBUSY) {
- *parent_ra_addr = old_parent_ra;
- return;
- }
-
/*
* Get the recorded ip of the current mcount calling site in the
* __mcount_loc section, which will be used to filter the function
@@ -382,13 +375,10 @@ void prepare_ftrace_return(unsigned long
*/
insns = core_kernel_text(self_ra) ? 2 : MCOUNT_OFFSET_INSNS + 1;
- trace.func = self_ra - (MCOUNT_INSN_SIZE * insns);
+ self_ra -= (MCOUNT_INSN_SIZE * insns);
- /* Only trace if the calling function expects to */
- if (!ftrace_graph_entry(&trace)) {
- current->curr_ret_stack--;
+ if (function_graph_enter(old_parent_ra, self_ra, fp, NULL))
*parent_ra_addr = old_parent_ra;
- }
return;
out:
ftrace_graph_stop();
