[for-next][PATCH 08/24] arm64: Use ftrace_graph_get_ret_stack() instead of curr_ret_stack

Steven Rostedt
2018-12-21T17:58:26Z

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

The structure of the ret_stack array on the task struct is going to
change, and accessing it directly via the curr_ret_stack index will no
longer give the ret_stack entry that holds the return address. To access
that, architectures must now use ftrace_graph_get_ret_stack() to get the
associated ret_stack that matches the saved return address.

Cc: linux-arm-kernel@lists.infradead.org
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
arch/arm64/kernel/perf_callchain.c | 2 +-
arch/arm64/kernel/process.c | 2 +-
arch/arm64/kernel/return_address.c | 2 +-
arch/arm64/kernel/stacktrace.c | 12 +++++++-----
arch/arm64/kernel/time.c | 2 +-
arch/arm64/kernel/traps.c | 2 +-
6 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/kernel/perf_callchain.c b/arch/arm64/kernel/perf_callchain.c
index bcafd7dcfe8b..1b792b46604e 100644
--- a/arch/arm64/kernel/perf_callchain.c
+++ b/arch/arm64/kernel/perf_callchain.c
@@ -164,7 +164,7 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
frame.fp = regs->regs[29];
frame.pc = regs->pc;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- frame.graph = current->curr_ret_stack;
+ frame.graph = 0;
#endif

walk_stackframe(current, &frame, callchain_trace, entry);
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index d9a4c2d6dd8b..37a66394b07d 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -459,7 +459,7 @@ unsigned long get_wchan(struct task_struct *p)
frame.fp = thread_saved_fp(p);
frame.pc = thread_saved_pc(p);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- frame.graph = p->curr_ret_stack;
+ frame.graph = 0;
#endif
do {
if (unwind_frame(p, &frame))
diff --git a/arch/arm64/kernel/return_address.c b/arch/arm64/kernel/return_address.c
index 933adbc0f654..53c40196b607 100644
--- a/arch/arm64/kernel/return_address.c
+++ b/arch/arm64/kernel/return_address.c
@@ -44,7 +44,7 @@ void *return_address(unsigned int level)
frame.fp = (unsigned long)__builtin_frame_address(0);
frame.pc = (unsigned long)return_address; /* dummy */
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- frame.graph = current->curr_ret_stack;
+ frame.graph = 0;
#endif

walk_stackframe(current, &frame, save_return_addr, &data);
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index 7723dadf25be..1a29f2695ff2 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -59,15 +59,17 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
if (tsk->ret_stack &&
(frame->pc == (unsigned long)return_to_handler)) {
- if (WARN_ON_ONCE(frame->graph == -1))
- return -EINVAL;
+ struct ftrace_ret_stack *ret_stack;
/*
* This is a case where function graph tracer has
* modified a return address (LR) in a stack frame
* to hook a function return.
* So replace it to an original value.
*/
- frame->pc = tsk->ret_stack[frame->graph--].ret;
+ ret_stack = ftrace_graph_get_ret_stack(tsk, frame->graph++);
+ if (WARN_ON_ONCE(!ret_stack))
+ return -EINVAL;
+ frame->pc = ret_stack->ret;
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

@@ -134,7 +136,7 @@ void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
frame.fp = regs->regs[29];
frame.pc = regs->pc;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- frame.graph = current->curr_ret_stack;
+ frame.graph = 0;
#endif

walk_stackframe(current, &frame, save_trace, &data);
@@ -165,7 +167,7 @@ static noinline void __save_stack_trace(struct task_struct *tsk,
frame.pc = (unsigned long)__save_stack_trace;
}
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- frame.graph = tsk->curr_ret_stack;
+ frame.graph = 0;
#endif

walk_stackframe(tsk, &frame, save_trace, &data);
diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c
index f258636273c9..a777ae90044d 100644
--- a/arch/arm64/kernel/time.c
+++ b/arch/arm64/kernel/time.c
@@ -52,7 +52,7 @@ unsigned long profile_pc(struct pt_regs *regs)
frame.fp = regs->regs[29];
frame.pc = regs->pc;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- frame.graph = current->curr_ret_stack;
+ frame.graph = 0;
#endif
do {
int ret = unwind_frame(NULL, &frame);
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 5f4d9acb32f5..49ebf3771391 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -122,7 +122,7 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
frame.pc = thread_saved_pc(tsk);
}
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- frame.graph = tsk->curr_ret_stack;
+ frame.graph = 0;
#endif

skip = !!regs;
--
2.19.2