Re: [PATCH v14 04/19] function_graph: Replace fgraph_ret_regs with ftrace_regs

Steven Rostedt
2024-09-15T09:17:49Z

Can I get an Acked-by from the X86 maintainers for this patch?

Thanks!

-- Steve

On Fri, 13 Sep 2024 00:08:51 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:

> From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
>
> Use ftrace_regs instead of fgraph_ret_regs for tracing return value
> on function_graph tracer because of simplifying the callback interface.
>
> The CONFIG_HAVE_FUNCTION_GRAPH_RETVAL is also replaced by
> CONFIG_HAVE_FUNCTION_GRAPH_FREGS.
>
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> ---
> Changes in v8:
> - Newly added.
> ---
> arch/arm64/Kconfig | 1 +
> arch/arm64/include/asm/ftrace.h | 23 ++++++-----------------
> arch/arm64/kernel/asm-offsets.c | 12 ------------
> arch/arm64/kernel/entry-ftrace.S | 32 ++++++++++++++++++--------------
> arch/loongarch/Kconfig | 2 +-
> arch/loongarch/include/asm/ftrace.h | 24 ++----------------------
> arch/loongarch/kernel/asm-offsets.c | 12 ------------
> arch/loongarch/kernel/mcount.S | 17 ++++++++++-------
> arch/loongarch/kernel/mcount_dyn.S | 14 +++++++-------
> arch/riscv/Kconfig | 2 +-
> arch/riscv/include/asm/ftrace.h | 26 +++++---------------------
> arch/riscv/kernel/mcount.S | 24 +++++++++++++-----------
> arch/s390/Kconfig | 2 +-
> arch/s390/include/asm/ftrace.h | 26 +++++++++-----------------
> arch/s390/kernel/asm-offsets.c | 6 ------
> arch/s390/kernel/mcount.S | 9 +++++----
> arch/x86/Kconfig | 2 +-
> arch/x86/include/asm/ftrace.h | 22 ++--------------------
> arch/x86/kernel/ftrace_32.S | 15 +++++++++------
> arch/x86/kernel/ftrace_64.S | 17 +++++++++--------
> include/linux/ftrace.h | 14 +++++++++++---
> kernel/trace/Kconfig | 4 ++--
> kernel/trace/fgraph.c | 21 +++++++++------------
> 23 files changed, 122 insertions(+), 205 deletions(-)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index a2f8ff354ca6..17947f625b06 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -211,6 +211,7 @@ config ARM64
> select HAVE_FTRACE_MCOUNT_RECORD
> select HAVE_FUNCTION_TRACER
> select HAVE_FUNCTION_ERROR_INJECTION
> + select HAVE_FUNCTION_GRAPH_FREGS
> select HAVE_FUNCTION_GRAPH_TRACER
> select HAVE_FUNCTION_GRAPH_RETVAL
> select HAVE_GCC_PLUGINS
> diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
> index dc9cf0bd2a4c..dffaab3dd1f1 100644
> --- a/arch/arm64/include/asm/ftrace.h
> +++ b/arch/arm64/include/asm/ftrace.h
> @@ -126,6 +126,12 @@ ftrace_override_function_with_return(struct ftrace_regs *fregs)
> fregs->pc = fregs->lr;
> }
>
> +static __always_inline unsigned long
> +ftrace_regs_get_frame_pointer(const struct ftrace_regs *fregs)
> +{
> + return fregs->fp;
> +}
> +
> int ftrace_regs_query_register_offset(const char *name);
>
> int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
> @@ -183,23 +189,6 @@ static inline bool arch_syscall_match_sym_name(const char *sym,
>
> #ifndef __ASSEMBLY__
> #ifdef CONFIG_FUNCTION_GRAPH_TRACER
> -struct fgraph_ret_regs {
> - /* x0 - x7 */
> - unsigned long regs[8];
> -
> - 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;
> -}
>
> void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
> unsigned long frame_pointer);
> diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
> index 27de1dddb0ab..9e03c9a7e5c3 100644
> --- a/arch/arm64/kernel/asm-offsets.c
> +++ b/arch/arm64/kernel/asm-offsets.c
> @@ -201,18 +201,6 @@ int main(void)
> DEFINE(FTRACE_OPS_FUNC, offsetof(struct ftrace_ops, func));
> #endif
> BLANK();
> -#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> - DEFINE(FGRET_REGS_X0, offsetof(struct fgraph_ret_regs, regs[0]));
> - DEFINE(FGRET_REGS_X1, offsetof(struct fgraph_ret_regs, regs[1]));
> - DEFINE(FGRET_REGS_X2, offsetof(struct fgraph_ret_regs, regs[2]));
> - DEFINE(FGRET_REGS_X3, offsetof(struct fgraph_ret_regs, regs[3]));
> - DEFINE(FGRET_REGS_X4, offsetof(struct fgraph_ret_regs, regs[4]));
> - DEFINE(FGRET_REGS_X5, offsetof(struct fgraph_ret_regs, regs[5]));
> - DEFINE(FGRET_REGS_X6, offsetof(struct fgraph_ret_regs, regs[6]));
> - DEFINE(FGRET_REGS_X7, offsetof(struct fgraph_ret_regs, regs[7]));
> - DEFINE(FGRET_REGS_FP, offsetof(struct fgraph_ret_regs, fp));
> - DEFINE(FGRET_REGS_SIZE, sizeof(struct fgraph_ret_regs));
> -#endif
> #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
> DEFINE(FTRACE_OPS_DIRECT_CALL, offsetof(struct ftrace_ops, direct_call));
> #endif
> diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S
> index f0c16640ef21..169ccf600066 100644
> --- a/arch/arm64/kernel/entry-ftrace.S
> +++ b/arch/arm64/kernel/entry-ftrace.S
> @@ -329,24 +329,28 @@ SYM_FUNC_END(ftrace_stub_graph)
> * @fp is checked against the value passed by ftrace_graph_caller().
> */
> SYM_CODE_START(return_to_handler)
> - /* save return value regs */
> - sub sp, sp, #FGRET_REGS_SIZE
> - stp x0, x1, [sp, #FGRET_REGS_X0]
> - stp x2, x3, [sp, #FGRET_REGS_X2]
> - stp x4, x5, [sp, #FGRET_REGS_X4]
> - stp x6, x7, [sp, #FGRET_REGS_X6]
> - str x29, [sp, #FGRET_REGS_FP] // parent's fp
> + /* Make room for ftrace_regs */
> + sub sp, sp, #FREGS_SIZE
> +
> + /* Save return value regs */
> + stp x0, x1, [sp, #FREGS_X0]
> + stp x2, x3, [sp, #FREGS_X2]
> + stp x4, x5, [sp, #FREGS_X4]
> + stp x6, x7, [sp, #FREGS_X6]
> +
> + /* Save the callsite's FP */
> + str x29, [sp, #FREGS_FP]
>
> mov x0, sp
> - bl ftrace_return_to_handler // addr = ftrace_return_to_hander(regs);
> + bl ftrace_return_to_handler // addr = ftrace_return_to_hander(fregs);
> mov x30, x0 // restore the original return address
>
> - /* restore return value regs */
> - ldp x0, x1, [sp, #FGRET_REGS_X0]
> - ldp x2, x3, [sp, #FGRET_REGS_X2]
> - ldp x4, x5, [sp, #FGRET_REGS_X4]
> - ldp x6, x7, [sp, #FGRET_REGS_X6]
> - add sp, sp, #FGRET_REGS_SIZE
> + /* Restore return value regs */
> + ldp x0, x1, [sp, #FREGS_X0]
> + ldp x2, x3, [sp, #FREGS_X2]
> + ldp x4, x5, [sp, #FREGS_X4]
> + ldp x6, x7, [sp, #FREGS_X6]
> + add sp, sp, #FREGS_SIZE
>
> ret
> SYM_CODE_END(return_to_handler)
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> index 70f169210b52..974f08f65f63 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -131,7 +131,7 @@ config LOONGARCH
> select HAVE_FTRACE_MCOUNT_RECORD
> select HAVE_FUNCTION_ARG_ACCESS_API
> select HAVE_FUNCTION_ERROR_INJECTION
> - select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
> + select HAVE_FUNCTION_GRAPH_FREGS
> select HAVE_FUNCTION_GRAPH_TRACER
> select HAVE_FUNCTION_TRACER
> select HAVE_GCC_PLUGINS
> diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/asm/ftrace.h
> index 6f8517d59954..1a73f35ea9af 100644
> --- a/arch/loongarch/include/asm/ftrace.h
> +++ b/arch/loongarch/include/asm/ftrace.h
> @@ -77,6 +77,8 @@ ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs, unsigned long ip)
> override_function_with_return(&(fregs)->regs)
> #define ftrace_regs_query_register_offset(name) \
> regs_query_register_offset(name)
> +#define ftrace_regs_get_frame_pointer(fregs) \
> + ((fregs)->regs.regs[22])
>
> #define ftrace_graph_func ftrace_graph_func
> void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
> @@ -99,26 +101,4 @@ __arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr)
>
> #endif /* CONFIG_FUNCTION_TRACER */
>
> -#ifndef __ASSEMBLY__
> -#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> -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 /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */
> -#endif
> -
> #endif /* _ASM_LOONGARCH_FTRACE_H */
> diff --git a/arch/loongarch/kernel/asm-offsets.c b/arch/loongarch/kernel/asm-offsets.c
> index bee9f7a3108f..714f5b5f1956 100644
> --- a/arch/loongarch/kernel/asm-offsets.c
> +++ b/arch/loongarch/kernel/asm-offsets.c
> @@ -279,18 +279,6 @@ static void __used output_pbe_defines(void)
> }
> #endif
>
> -#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> -static void __used output_fgraph_ret_regs_defines(void)
> -{
> - COMMENT("LoongArch fgraph_ret_regs offsets.");
> - 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();
> -}
> -#endif
> -
> static void __used output_kvm_defines(void)
> {
> COMMENT("KVM/LoongArch Specific offsets.");
> diff --git a/arch/loongarch/kernel/mcount.S b/arch/loongarch/kernel/mcount.S
> index 3015896016a0..b6850503e061 100644
> --- a/arch/loongarch/kernel/mcount.S
> +++ b/arch/loongarch/kernel/mcount.S
> @@ -79,10 +79,11 @@ SYM_FUNC_START(ftrace_graph_caller)
> SYM_FUNC_END(ftrace_graph_caller)
>
> SYM_FUNC_START(return_to_handler)
> - 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
> + /* Save return value regs */
> + PTR_ADDI sp, sp, -PT_SIZE
> + PTR_S a0, sp, PT_R4
> + PTR_S a1, sp, PT_R5
> + PTR_S zero, sp, PT_R22
>
> move a0, sp
> bl ftrace_return_to_handler
> @@ -90,9 +91,11 @@ SYM_FUNC_START(return_to_handler)
> /* Restore the real parent address: a0 -> ra */
> move ra, a0
>
> - PTR_L a0, sp, FGRET_REGS_A0
> - PTR_L a1, sp, FGRET_REGS_A1
> - PTR_ADDI sp, sp, FGRET_REGS_SIZE
> + /* Restore return value regs */
> + PTR_L a0, sp, PT_R4
> + PTR_L a1, sp, PT_R5
> + PTR_ADDI sp, sp, PT_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 0c65cf09110c..d6b474ad1d5e 100644
> --- a/arch/loongarch/kernel/mcount_dyn.S
> +++ b/arch/loongarch/kernel/mcount_dyn.S
> @@ -140,19 +140,19 @@ SYM_CODE_END(ftrace_graph_caller)
> SYM_CODE_START(return_to_handler)
> UNWIND_HINT_UNDEFINED
> /* Save return value regs */
> - 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
> + PTR_ADDI sp, sp, -PT_SIZE
> + PTR_S a0, sp, PT_R4
> + PTR_S a1, sp, PT_R5
> + PTR_S zero, sp, PT_R22
>
> move a0, sp
> bl ftrace_return_to_handler
> move ra, a0
>
> /* Restore return value regs */
> - PTR_L a0, sp, FGRET_REGS_A0
> - PTR_L a1, sp, FGRET_REGS_A1
> - PTR_ADDI sp, sp, FGRET_REGS_SIZE
> + PTR_L a0, sp, PT_R4
> + PTR_L a1, sp, PT_R5
> + PTR_ADDI sp, sp, PT_SIZE
>
> jr ra
> SYM_CODE_END(return_to_handler)
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 0f3cd7c3a436..6e8422269ba4 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -140,7 +140,7 @@ config RISCV
> select HAVE_DYNAMIC_FTRACE_WITH_ARGS if HAVE_DYNAMIC_FTRACE
> select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
> select HAVE_FUNCTION_GRAPH_TRACER
> - select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
> + select HAVE_FUNCTION_GRAPH_FREGS
> select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION
> select HAVE_EBPF_JIT if MMU
> select HAVE_GUP_FAST if MMU
> diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h
> index 2cddd79ff21b..e9f364ce9fe8 100644
> --- a/arch/riscv/include/asm/ftrace.h
> +++ b/arch/riscv/include/asm/ftrace.h
> @@ -164,6 +164,11 @@ static __always_inline unsigned long ftrace_regs_get_stack_pointer(const struct
> return fregs->sp;
> }
>
> +static __always_inline unsigned long ftrace_regs_get_frame_pointer(const struct ftrace_regs *fregs)
> +{
> + return fregs->s0;
> +}
> +
> static __always_inline unsigned long ftrace_regs_get_argument(struct ftrace_regs *fregs,
> unsigned int n)
> {
> @@ -204,25 +209,4 @@ static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs, unsi
>
> #endif /* CONFIG_DYNAMIC_FTRACE */
>
> -#ifndef __ASSEMBLY__
> -#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> -struct fgraph_ret_regs {
> - unsigned long a1;
> - unsigned long a0;
> - unsigned long s0;
> - unsigned long ra;
> -};
> -
> -static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret_regs *ret_regs)
> -{
> - return ret_regs->a0;
> -}
> -
> -static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs *ret_regs)
> -{
> - return ret_regs->s0;
> -}
> -#endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */
> -#endif
> -
> #endif /* _ASM_RISCV_FTRACE_H */
> diff --git a/arch/riscv/kernel/mcount.S b/arch/riscv/kernel/mcount.S
> index 3a42f6287909..068168046e0e 100644
> --- a/arch/riscv/kernel/mcount.S
> +++ b/arch/riscv/kernel/mcount.S
> @@ -12,6 +12,8 @@
> #include <asm/asm-offsets.h>
> #include <asm/ftrace.h>
>
> +#define ABI_SIZE_ON_STACK 80
> +
> .text
>
> .macro SAVE_ABI_STATE
> @@ -26,12 +28,12 @@
> * register if a0 was not saved.
> */
> .macro SAVE_RET_ABI_STATE
> - addi sp, sp, -4*SZREG
> - REG_S s0, 2*SZREG(sp)
> - REG_S ra, 3*SZREG(sp)
> - REG_S a0, 1*SZREG(sp)
> - REG_S a1, 0*SZREG(sp)
> - addi s0, sp, 4*SZREG
> + addi sp, sp, -ABI_SIZE_ON_STACK
> + REG_S ra, 1*SZREG(sp)
> + REG_S s0, 8*SZREG(sp)
> + REG_S a0, 10*SZREG(sp)
> + REG_S a1, 11*SZREG(sp)
> + addi s0, sp, ABI_SIZE_ON_STACK
> .endm
>
> .macro RESTORE_ABI_STATE
> @@ -41,11 +43,11 @@
> .endm
>
> .macro RESTORE_RET_ABI_STATE
> - REG_L ra, 3*SZREG(sp)
> - REG_L s0, 2*SZREG(sp)
> - REG_L a0, 1*SZREG(sp)
> - REG_L a1, 0*SZREG(sp)
> - addi sp, sp, 4*SZREG
> + REG_L ra, 1*SZREG(sp)
> + REG_L s0, 8*SZREG(sp)
> + REG_L a0, 10*SZREG(sp)
> + REG_L a1, 11*SZREG(sp)
> + addi sp, sp, ABI_SIZE_ON_STACK
> .endm
>
> SYM_TYPED_FUNC_START(ftrace_stub)
> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> index a822f952f64a..12e942cfbcde 100644
> --- a/arch/s390/Kconfig
> +++ b/arch/s390/Kconfig
> @@ -184,7 +184,7 @@ config S390
> select HAVE_FTRACE_MCOUNT_RECORD
> select HAVE_FUNCTION_ARG_ACCESS_API
> select HAVE_FUNCTION_ERROR_INJECTION
> - select HAVE_FUNCTION_GRAPH_RETVAL
> + select HAVE_FUNCTION_GRAPH_FREGS
> select HAVE_FUNCTION_GRAPH_TRACER
> select HAVE_FUNCTION_TRACER
> select HAVE_GCC_PLUGINS
> diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
> index de76c21eb4a3..9cdd48a46bf7 100644
> --- a/arch/s390/include/asm/ftrace.h
> +++ b/arch/s390/include/asm/ftrace.h
> @@ -49,23 +49,6 @@ static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *
> return NULL;
> }
>
> -#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> -struct fgraph_ret_regs {
> - unsigned long gpr2;
> - unsigned long fp;
> -};
> -
> -static __always_inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret_regs *ret_regs)
> -{
> - return ret_regs->gpr2;
> -}
> -
> -static __always_inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs *ret_regs)
> -{
> - return ret_regs->fp;
> -}
> -#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
> -
> static __always_inline unsigned long
> ftrace_regs_get_instruction_pointer(const struct ftrace_regs *fregs)
> {
> @@ -92,6 +75,15 @@ ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
> #define ftrace_regs_query_register_offset(name) \
> regs_query_register_offset(name)
>
> +static __always_inline unsigned long
> +ftrace_regs_get_frame_pointer(struct ftrace_regs *fregs)
> +{
> + unsigned long *sp;
> +
> + sp = (void *)ftrace_regs_get_stack_pointer(fregs);
> + return sp[0]; /* return backchain */
> +}
> +
> #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
> /*
> * When an ftrace registered caller is tracing a function that is
> diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
> index ffa0dd2dbaac..d38ed80615d5 100644
> --- a/arch/s390/kernel/asm-offsets.c
> +++ b/arch/s390/kernel/asm-offsets.c
> @@ -179,12 +179,6 @@ int main(void)
> DEFINE(OLDMEM_SIZE, PARMAREA + offsetof(struct parmarea, oldmem_size));
> DEFINE(COMMAND_LINE, PARMAREA + offsetof(struct parmarea, command_line));
> DEFINE(MAX_COMMAND_LINE_SIZE, PARMAREA + offsetof(struct parmarea, max_command_line_size));
> -#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> - /* function graph return value tracing */
> - OFFSET(__FGRAPH_RET_GPR2, fgraph_ret_regs, gpr2);
> - OFFSET(__FGRAPH_RET_FP, fgraph_ret_regs, fp);
> - DEFINE(__FGRAPH_RET_SIZE, sizeof(struct fgraph_ret_regs));
> -#endif
> OFFSET(__FTRACE_REGS_PT_REGS, ftrace_regs, regs);
> DEFINE(__FTRACE_REGS_SIZE, sizeof(struct ftrace_regs));
>
> diff --git a/arch/s390/kernel/mcount.S b/arch/s390/kernel/mcount.S
> index ae4d4fd9afcd..cda798b976de 100644
> --- a/arch/s390/kernel/mcount.S
> +++ b/arch/s390/kernel/mcount.S
> @@ -133,14 +133,15 @@ SYM_CODE_END(ftrace_common)
> SYM_FUNC_START(return_to_handler)
> stmg %r2,%r5,32(%r15)
> lgr %r1,%r15
> - aghi %r15,-(STACK_FRAME_OVERHEAD+__FGRAPH_RET_SIZE)
> +# Allocate ftrace_regs + backchain on the stack
> + aghi %r15,-STACK_FRAME_SIZE_FREGS
> stg %r1,__SF_BACKCHAIN(%r15)
> la %r3,STACK_FRAME_OVERHEAD(%r15)
> - stg %r1,__FGRAPH_RET_FP(%r3)
> - stg %r2,__FGRAPH_RET_GPR2(%r3)
> + stg %r2,(__SF_GPRS+2*8)(%r15)
> + stg %r15,(__SF_GPRS+15*8)(%r15)
> lgr %r2,%r3
> brasl %r14,ftrace_return_to_handler
> - aghi %r15,STACK_FRAME_OVERHEAD+__FGRAPH_RET_SIZE
> + aghi %r15,STACK_FRAME_SIZE_FREGS
> lgr %r14,%r2
> lmg %r2,%r5,32(%r15)
> BR_EX %r14
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 007bab9f2a0e..047384e4d93a 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -228,7 +228,7 @@ config X86
> select HAVE_GUP_FAST
> select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
> select HAVE_FTRACE_MCOUNT_RECORD
> - select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
> + select HAVE_FUNCTION_GRAPH_FREGS if HAVE_FUNCTION_GRAPH_TRACER
> select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE)
> select HAVE_FUNCTION_TRACER
> select HAVE_GCC_PLUGINS
> diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
> index 78f6a200e15b..669771ef3b5b 100644
> --- a/arch/x86/include/asm/ftrace.h
> +++ b/arch/x86/include/asm/ftrace.h
> @@ -64,6 +64,8 @@ arch_ftrace_get_regs(struct ftrace_regs *fregs)
> override_function_with_return(&(fregs)->regs)
> #define ftrace_regs_query_register_offset(name) \
> regs_query_register_offset(name)
> +#define ftrace_regs_get_frame_pointer(fregs) \
> + frame_pointer(&(fregs)->regs)
>
> struct ftrace_ops;
> #define ftrace_graph_func ftrace_graph_func
> @@ -148,24 +150,4 @@ static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
> #endif /* !COMPILE_OFFSETS */
> #endif /* !__ASSEMBLY__ */
>
> -#ifndef __ASSEMBLY__
> -#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> -struct fgraph_ret_regs {
> - unsigned long ax;
> - unsigned long dx;
> - unsigned long bp;
> -};
> -
> -static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret_regs *ret_regs)
> -{
> - return ret_regs->ax;
> -}
> -
> -static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs *ret_regs)
> -{
> - return ret_regs->bp;
> -}
> -#endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */
> -#endif
> -
> #endif /* _ASM_X86_FTRACE_H */
> diff --git a/arch/x86/kernel/ftrace_32.S b/arch/x86/kernel/ftrace_32.S
> index 58d9ed50fe61..4b265884d06c 100644
> --- a/arch/x86/kernel/ftrace_32.S
> +++ b/arch/x86/kernel/ftrace_32.S
> @@ -23,6 +23,8 @@ SYM_FUNC_START(__fentry__)
> SYM_FUNC_END(__fentry__)
> EXPORT_SYMBOL(__fentry__)
>
> +#define FRAME_SIZE PT_OLDSS+4
> +
> SYM_CODE_START(ftrace_caller)
>
> #ifdef CONFIG_FRAME_POINTER
> @@ -187,14 +189,15 @@ SYM_CODE_END(ftrace_graph_caller)
>
> .globl return_to_handler
> return_to_handler:
> - pushl $0
> - pushl %edx
> - pushl %eax
> + subl $(FRAME_SIZE), %esp
> + movl $0, PT_EBP(%esp)
> + movl %edx, PT_EDX(%esp)
> + movl %eax, PT_EAX(%esp)
> movl %esp, %eax
> call ftrace_return_to_handler
> movl %eax, %ecx
> - popl %eax
> - popl %edx
> - addl $4, %esp # skip ebp
> + movl %eax, PT_EAX(%esp)
> + movl %edx, PT_EDX(%esp)
> + addl $(FRAME_SIZE), %esp
> JMP_NOSPEC ecx
> #endif
> diff --git a/arch/x86/kernel/ftrace_64.S b/arch/x86/kernel/ftrace_64.S
> index 214f30e9f0c0..d51647228596 100644
> --- a/arch/x86/kernel/ftrace_64.S
> +++ b/arch/x86/kernel/ftrace_64.S
> @@ -348,21 +348,22 @@ STACK_FRAME_NON_STANDARD_FP(__fentry__)
> SYM_CODE_START(return_to_handler)
> UNWIND_HINT_UNDEFINED
> ANNOTATE_NOENDBR
> - subq $24, %rsp
>
> - /* Save the return values */
> - movq %rax, (%rsp)
> - movq %rdx, 8(%rsp)
> - movq %rbp, 16(%rsp)
> + /* Save ftrace_regs for function exit context */
> + subq $(FRAME_SIZE), %rsp
> +
> + movq %rax, RAX(%rsp)
> + movq %rdx, RDX(%rsp)
> + movq %rbp, RBP(%rsp)
> movq %rsp, %rdi
>
> call ftrace_return_to_handler
>
> movq %rax, %rdi
> - movq 8(%rsp), %rdx
> - movq (%rsp), %rax
> + movq RDX(%rsp), %rdx
> + movq RAX(%rsp), %rax
>
> - addq $24, %rsp
> + addq $(FRAME_SIZE), %rsp
> /*
> * Jump back to the old return address. This cannot be JMP_NOSPEC rdi
> * since IBT would demand that contain ENDBR, which simply isn't so for
> diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
> index 1fe49a28de2d..13987cd63553 100644
> --- a/include/linux/ftrace.h
> +++ b/include/linux/ftrace.h
> @@ -43,9 +43,8 @@ struct dyn_ftrace;
>
> char *arch_ftrace_match_adjust(char *str, const char *search);
>
> -#ifdef CONFIG_HAVE_FUNCTION_GRAPH_RETVAL
> -struct fgraph_ret_regs;
> -unsigned long ftrace_return_to_handler(struct fgraph_ret_regs *ret_regs);
> +#ifdef CONFIG_HAVE_FUNCTION_GRAPH_FREGS
> +unsigned long ftrace_return_to_handler(struct ftrace_regs *fregs);
> #else
> unsigned long ftrace_return_to_handler(unsigned long frame_pointer);
> #endif
> @@ -134,6 +133,13 @@ extern int ftrace_enabled;
> * Also, architecture dependent fields can be used for internal process.
> * (e.g. orig_ax on x86_64)
> *
> + * Basically, ftrace_regs stores the registers related to the context.
> + * On function entry, registers for function parameters and hooking the
> + * function call are stored, and on function exit, registers for function
> + * return value and frame pointers are stored.
> + *
> + * And also, it dpends on the context that which registers are restored
> + * from the ftrace_regs.
> * On the function entry, those registers will be restored except for
> * the stack pointer, so that user can change the function parameters
> * and instruction pointer (e.g. live patching.)
> @@ -191,6 +197,8 @@ static __always_inline bool ftrace_regs_has_args(struct ftrace_regs *fregs)
> override_function_with_return(ftrace_get_regs(fregs))
> #define ftrace_regs_query_register_offset(name) \
> regs_query_register_offset(name)
> +#define ftrace_regs_get_frame_pointer(fregs) \
> + frame_pointer(&(fregs)->regs)
> #endif
>
> typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
> diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
> index 721c3b221048..ab277eff80dc 100644
> --- a/kernel/trace/Kconfig
> +++ b/kernel/trace/Kconfig
> @@ -31,7 +31,7 @@ config HAVE_FUNCTION_GRAPH_TRACER
> help
> See Documentation/trace/ftrace-design.rst
>
> -config HAVE_FUNCTION_GRAPH_RETVAL
> +config HAVE_FUNCTION_GRAPH_FREGS
> bool
>
> config HAVE_DYNAMIC_FTRACE
> @@ -232,7 +232,7 @@ config FUNCTION_GRAPH_TRACER
>
> config FUNCTION_GRAPH_RETVAL
> bool "Kernel Function Graph Return Value"
> - depends on HAVE_FUNCTION_GRAPH_RETVAL
> + depends on HAVE_FUNCTION_GRAPH_FREGS
> depends on FUNCTION_GRAPH_TRACER
> default n
> help
> diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
> index 0322c5723748..30bebe43607d 100644
> --- a/kernel/trace/fgraph.c
> +++ b/kernel/trace/fgraph.c
> @@ -763,15 +763,12 @@ static struct notifier_block ftrace_suspend_notifier = {
> .notifier_call = ftrace_suspend_notifier_call,
> };
>
> -/* fgraph_ret_regs is not defined without CONFIG_FUNCTION_GRAPH_RETVAL */
> -struct fgraph_ret_regs;
> -
> /*
> * Send the trace to the ring-buffer.
> * @return the original return address.
> */
> -static unsigned long __ftrace_return_to_handler(struct fgraph_ret_regs *ret_regs,
> - unsigned long frame_pointer)
> +static inline unsigned long
> +__ftrace_return_to_handler(struct ftrace_regs *fregs, unsigned long frame_pointer)
> {
> struct ftrace_ret_stack *ret_stack;
> struct ftrace_graph_ret trace;
> @@ -791,7 +788,7 @@ static unsigned long __ftrace_return_to_handler(struct fgraph_ret_regs *ret_regs
>
> trace.rettime = trace_clock_local();
> #ifdef CONFIG_FUNCTION_GRAPH_RETVAL
> - trace.retval = fgraph_ret_regs_return_value(ret_regs);
> + trace.retval = ftrace_regs_get_return_value(fregs);
> #endif
>
> bitmap = get_bitmap_bits(current, offset);
> @@ -826,14 +823,14 @@ static unsigned long __ftrace_return_to_handler(struct fgraph_ret_regs *ret_regs
> }
>
> /*
> - * After all architecures have selected HAVE_FUNCTION_GRAPH_RETVAL, we can
> - * leave only ftrace_return_to_handler(ret_regs).
> + * After all architecures have selected HAVE_FUNCTION_GRAPH_FREGS, we can
> + * leave only ftrace_return_to_handler(fregs).
> */
> -#ifdef CONFIG_HAVE_FUNCTION_GRAPH_RETVAL
> -unsigned long ftrace_return_to_handler(struct fgraph_ret_regs *ret_regs)
> +#ifdef CONFIG_HAVE_FUNCTION_GRAPH_FREGS
> +unsigned long ftrace_return_to_handler(struct ftrace_regs *fregs)
> {
> - return __ftrace_return_to_handler(ret_regs,
> - fgraph_ret_regs_frame_pointer(ret_regs));
> + return __ftrace_return_to_handler(fregs,
> + ftrace_regs_get_frame_pointer(fregs));
> }
> #else
> unsigned long ftrace_return_to_handler(unsigned long frame_pointer)