[PATCH v9 7/8] LoongArch: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL
Donglin Peng
pengdonglin at sangfor.com.cn
Thu Mar 30 06:07:42 PDT 2023
On 2023/3/30 20:48, Huacai Chen wrote:
> Hi, Donglin,
>
> On Thu, Mar 30, 2023 at 7:39 PM Donglin Peng <pengdonglin at sangfor.com.cn> 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 at sangfor.com.cn>
>> ---
>> 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
>>
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