Re: [PATCH v9 7/8] LoongArch: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL
From: Donglin Peng
Date: Thu Mar 30 2023 - 09:08:09 EST
On 2023/3/30 20:48, Huacai Chen wrote:
Hi, Donglin,
On Thu, Mar 30, 2023 at 7:39 PM Donglin Peng <pengdonglin@xxxxxxxxxxxxxx> wrote:
The previous patch ("function_graph: Support recording and printing
the return value of function") has laid the groundwork for the for
the funcgraph-retval, and this modification makes it available on
the LoongArch platform.
We introduce a new structure called fgraph_ret_regs for the LoongArch
platform to hold return registers and the frame pointer. We then fill
its content in the return_to_handler and pass its address to the
function ftrace_return_to_handler to record the return value.
Signed-off-by: Donglin Peng <pengdonglin@xxxxxxxxxxxxxx>
---
v9:
- Fix stack pointer align issues
- Update the commit message
v8:
- Modify the control range of CONFIG_HAVE_FUNCTION_GRAPH_RETVAL
---
arch/loongarch/Kconfig | 1 +
arch/loongarch/include/asm/ftrace.h | 20 ++++++++++++++++++++
arch/loongarch/kernel/asm-offsets.c | 12 ++++++++++++
arch/loongarch/kernel/mcount.S | 14 ++++++++------
arch/loongarch/kernel/mcount_dyn.S | 15 ++++++++-------
5 files changed, 49 insertions(+), 13 deletions(-)
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 7fd51257e0ed..4bf60132869b 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -99,6 +99,7 @@ config LOONGARCH
select HAVE_FAST_GUP
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_FUNCTION_ARG_ACCESS_API
+ select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_FUNCTION_TRACER
select HAVE_GENERIC_VDSO
diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/asm/ftrace.h
index 3418d32d4fc7..01e7f92de03c 100644
--- a/arch/loongarch/include/asm/ftrace.h
+++ b/arch/loongarch/include/asm/ftrace.h
@@ -63,4 +63,24 @@ void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
#endif /* CONFIG_FUNCTION_TRACER */
+#ifndef __ASSEMBLY__
+struct fgraph_ret_regs {
+ /* a0 - a1 */
+ unsigned long regs[2];
+
+ unsigned long fp;
+ unsigned long __unused;
+};
+
+static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret_regs *ret_regs)
+{
+ return ret_regs->regs[0];
+}
+
+static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs *ret_regs)
+{
+ return ret_regs->fp;
+}
+#endif
+
#endif /* _ASM_LOONGARCH_FTRACE_H */
diff --git a/arch/loongarch/kernel/asm-offsets.c b/arch/loongarch/kernel/asm-offsets.c
index 4bdb203fc66e..fab5bcddeb23 100644
--- a/arch/loongarch/kernel/asm-offsets.c
+++ b/arch/loongarch/kernel/asm-offsets.c
@@ -12,6 +12,7 @@
#include <asm/cpu-info.h>
#include <asm/ptrace.h>
#include <asm/processor.h>
+#include <asm/ftrace.h>
void output_ptreg_defines(void)
{
@@ -60,6 +61,17 @@ void output_ptreg_defines(void)
BLANK();
}
+
+void output_fgraph_ret_regs_defines(void)
+{
+ COMMENT(" LoongArch fgraph_ret_regs offsets. ");
No space needed at the beginning, and I prefer to move this function
to the end of this file.
Yes, I will fix it. I copy it from output_pbe_defines, and it has a
space at the beginning, so I will fix it too.
Huacai
+ OFFSET(FGRET_REGS_A0, fgraph_ret_regs, regs[0]);
+ OFFSET(FGRET_REGS_A1, fgraph_ret_regs, regs[1]);
+ OFFSET(FGRET_REGS_FP, fgraph_ret_regs, fp);
+ DEFINE(FGRET_REGS_SIZE, sizeof(struct fgraph_ret_regs));
+ BLANK();
+}
+
void output_task_defines(void)
{
COMMENT("LoongArch task_struct offsets.");
diff --git a/arch/loongarch/kernel/mcount.S b/arch/loongarch/kernel/mcount.S
index 8cdc1563cd33..cb8e5803de4b 100644
--- a/arch/loongarch/kernel/mcount.S
+++ b/arch/loongarch/kernel/mcount.S
@@ -79,18 +79,20 @@ SYM_FUNC_START(ftrace_graph_caller)
SYM_FUNC_END(ftrace_graph_caller)
SYM_FUNC_START(return_to_handler)
- PTR_ADDI sp, sp, -2 * SZREG
- PTR_S a0, sp, 0
- PTR_S a1, sp, SZREG
+ PTR_ADDI sp, sp, -FGRET_REGS_SIZE
+ PTR_S a0, sp, FGRET_REGS_A0
+ PTR_S a1, sp, FGRET_REGS_A1
+ PTR_S zero, sp, FGRET_REGS_FP
+ move a0, sp
bl ftrace_return_to_handler
/* Restore the real parent address: a0 -> ra */
move ra, a0
- PTR_L a0, sp, 0
- PTR_L a1, sp, SZREG
- PTR_ADDI sp, sp, 2 * SZREG
+ PTR_L a0, sp, FGRET_REGS_A0
+ PTR_L a1, sp, FGRET_REGS_A1
+ PTR_ADDI sp, sp, FGRET_REGS_SIZE
jr ra
SYM_FUNC_END(return_to_handler)
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
diff --git a/arch/loongarch/kernel/mcount_dyn.S b/arch/loongarch/kernel/mcount_dyn.S
index bbabf06244c2..ec24ae1de741 100644
--- a/arch/loongarch/kernel/mcount_dyn.S
+++ b/arch/loongarch/kernel/mcount_dyn.S
@@ -131,18 +131,19 @@ SYM_CODE_END(ftrace_graph_caller)
SYM_CODE_START(return_to_handler)
/* Save return value regs */
- PTR_ADDI sp, sp, -2 * SZREG
- PTR_S a0, sp, 0
- PTR_S a1, sp, SZREG
+ PTR_ADDI sp, sp, -FGRET_REGS_SIZE
+ PTR_S a0, sp, FGRET_REGS_A0
+ PTR_S a1, sp, FGRET_REGS_A1
+ PTR_S zero, sp, FGRET_REGS_FP
- move a0, zero
+ move a0, sp
bl ftrace_return_to_handler
move ra, a0
/* Restore return value regs */
- PTR_L a0, sp, 0
- PTR_L a1, sp, SZREG
- PTR_ADDI sp, sp, 2 * SZREG
+ PTR_L a0, sp, FGRET_REGS_A0
+ PTR_L a1, sp, FGRET_REGS_A1
+ PTR_ADDI sp, sp, FGRET_REGS_SIZE
jr ra
SYM_CODE_END(return_to_handler)
--
2.25.1