Messages in this thread Patch in this message | | | From | Alan Kao <> | Subject | [PATCH 6/6] riscv/ftrace: Add HAVE_FUNCTION_GRAPH_RET_ADDR_PTR support | Date | Wed, 10 Jan 2018 15:38:14 +0800 |
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When doing unwinding in the function walk_stackframe, the pc now receives the address from calling ftrace_graph_ret_addr instead of manual calculation.
Note that the original expression, pc = frame->ra - 4 is buggy if the instruction at the return address happened to be a compressed inst. But since it is not a critical part of ftrace and is a RISC-V-specific behavior, it is ignored for now to ease the review process.
Cc: Greentime Hu <greentime@andestech.com> Signed-off-by: Alan Kao <alankao@andestech.com> --- arch/riscv/include/asm/ftrace.h | 1 + arch/riscv/kernel/ftrace.c | 2 +- arch/riscv/kernel/stacktrace.c | 6 ++++++ 3 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h index 429a6a156645..6e4b4c96b63e 100644 --- a/arch/riscv/include/asm/ftrace.h +++ b/arch/riscv/include/asm/ftrace.h @@ -8,6 +8,7 @@ #if defined(CONFIG_FUNCTION_GRAPH_TRACER) && defined(CONFIG_FRAME_POINTER) #define HAVE_FUNCTION_GRAPH_FP_TEST #endif +#define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR #define ARCH_SUPPORTS_FTRACE_OPS 1 #ifndef __ASSEMBLY__ diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c index c9cc884961d7..e02ecd44fe47 100644 --- a/arch/riscv/kernel/ftrace.c +++ b/arch/riscv/kernel/ftrace.c @@ -144,7 +144,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, return; err = ftrace_push_return_trace(old, self_addr, &trace.depth, - frame_pointer, NULL); + frame_pointer, parent); if (err == -EBUSY) return; *parent = return_hooker; diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c index 559aae781154..a4b1d94371a0 100644 --- a/arch/riscv/kernel/stacktrace.c +++ b/arch/riscv/kernel/stacktrace.c @@ -18,6 +18,7 @@ #include <linux/sched/debug.h> #include <linux/sched/task_stack.h> #include <linux/stacktrace.h> +#include <linux/ftrace.h> #ifdef CONFIG_FRAME_POINTER @@ -63,7 +64,12 @@ static void notrace walk_stackframe(struct task_struct *task, frame = (struct stackframe *)fp - 1; sp = fp; fp = frame->fp; +#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR + pc = ftrace_graph_ret_addr(current, NULL, frame->ra, + (unsigned long *)(fp - 8)); +#else pc = frame->ra - 0x4; +#endif } } -- 2.15.1
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