4.19-stable review patch. If anyone has any objections, please let me know.
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From: Steven Rostedt (VMware) rostedt@goodmis.org
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@linux-mips.org Cc: Paul Burton paul.burton@mips.com Cc: James Hogan jhogan@kernel.org Cc: linux-mips@linux-mips.org Cc: stable@kernel.org Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback") Reviewed-by: Masami Hiramatsu mhiramat@kernel.org Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- 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();