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 ARM64 platform.
We introduce a new structure called fgraph_ret_regs for the ARM64
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 <[email protected]>
---
v10:
- Use CONFIG_FUNCTION_GRAPH_TRACER to control fgraph_ret_regs definition
v9:
- Update the commit message
v8:
- Fix issues in ARM64 asm code
- Modify the control range of CONFIG_HAVE_FUNCTION_GRAPH_RETVAL
---
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/ftrace.h | 22 ++++++++++++++++++++++
arch/arm64/kernel/asm-offsets.c | 13 +++++++++++++
arch/arm64/kernel/entry-ftrace.S | 27 ++++++++++++++-------------
4 files changed, 50 insertions(+), 13 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1023e896d46b..48856d230800 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -195,6 +195,7 @@ config ARM64
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_ERROR_INJECTION
+ select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_GCC_PLUGINS
select HAVE_HW_BREAKPOINT if PERF_EVENTS
diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index 1c2672bbbf37..657adcbd80a4 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -170,4 +170,26 @@ static inline bool arch_syscall_match_sym_name(const char *sym,
}
#endif /* ifndef __ASSEMBLY__ */
+#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;
+}
+#endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */
+#endif
+
#endif /* __ASM_FTRACE_H */
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index ae345b06e9f7..75082e0409bf 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -197,6 +197,19 @@ int main(void)
#endif
#ifdef CONFIG_FUNCTION_TRACER
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
return 0;
}
diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S
index 350ed81324ac..da1443bcf776 100644
--- a/arch/arm64/kernel/entry-ftrace.S
+++ b/arch/arm64/kernel/entry-ftrace.S
@@ -270,22 +270,23 @@ SYM_FUNC_END(ftrace_stub_graph)
*/
SYM_CODE_START(return_to_handler)
/* save return value regs */
- sub sp, sp, #64
- stp x0, x1, [sp]
- stp x2, x3, [sp, #16]
- stp x4, x5, [sp, #32]
- stp x6, x7, [sp, #48]
+ 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
- mov x0, x29 // parent's fp
- bl ftrace_return_to_handler// addr = ftrace_return_to_hander(fp);
- mov x30, x0 // restore the original return address
+ mov x0, sp
+ bl ftrace_return_to_handler // addr = ftrace_return_to_hander(regs);
+ mov x30, x0 // restore the original return address
/* restore return value regs */
- ldp x0, x1, [sp]
- ldp x2, x3, [sp, #16]
- ldp x4, x5, [sp, #32]
- ldp x6, x7, [sp, #48]
- add sp, sp, #64
+ 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
ret
SYM_CODE_END(return_to_handler)
--
2.25.1
On Fri, Mar 31, 2023 at 05:47:40AM -0700, Donglin Peng 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 ARM64 platform.
>
> We introduce a new structure called fgraph_ret_regs for the ARM64
> 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 <[email protected]>
Thanks for working through all the feedback!
The structual changes all look good to me, and I've given this a spin to check
that it doesn't break graph tracing, so:
Reviewed-by: Mark Rutland <[email protected]>
Tested-by: Mark Rutland <[email protected]>
Mark.
> ---
> v10:
> - Use CONFIG_FUNCTION_GRAPH_TRACER to control fgraph_ret_regs definition
>
> v9:
> - Update the commit message
>
> v8:
> - Fix issues in ARM64 asm code
> - Modify the control range of CONFIG_HAVE_FUNCTION_GRAPH_RETVAL
> ---
> arch/arm64/Kconfig | 1 +
> arch/arm64/include/asm/ftrace.h | 22 ++++++++++++++++++++++
> arch/arm64/kernel/asm-offsets.c | 13 +++++++++++++
> arch/arm64/kernel/entry-ftrace.S | 27 ++++++++++++++-------------
> 4 files changed, 50 insertions(+), 13 deletions(-)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 1023e896d46b..48856d230800 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -195,6 +195,7 @@ config ARM64
> select HAVE_FTRACE_MCOUNT_RECORD
> select HAVE_FUNCTION_TRACER
> select HAVE_FUNCTION_ERROR_INJECTION
> + select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
> select HAVE_FUNCTION_GRAPH_TRACER
> select HAVE_GCC_PLUGINS
> select HAVE_HW_BREAKPOINT if PERF_EVENTS
> diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
> index 1c2672bbbf37..657adcbd80a4 100644
> --- a/arch/arm64/include/asm/ftrace.h
> +++ b/arch/arm64/include/asm/ftrace.h
> @@ -170,4 +170,26 @@ static inline bool arch_syscall_match_sym_name(const char *sym,
> }
> #endif /* ifndef __ASSEMBLY__ */
>
> +#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;
> +}
> +#endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */
> +#endif
> +
> #endif /* __ASM_FTRACE_H */
> diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
> index ae345b06e9f7..75082e0409bf 100644
> --- a/arch/arm64/kernel/asm-offsets.c
> +++ b/arch/arm64/kernel/asm-offsets.c
> @@ -197,6 +197,19 @@ int main(void)
> #endif
> #ifdef CONFIG_FUNCTION_TRACER
> 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
> return 0;
> }
> diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S
> index 350ed81324ac..da1443bcf776 100644
> --- a/arch/arm64/kernel/entry-ftrace.S
> +++ b/arch/arm64/kernel/entry-ftrace.S
> @@ -270,22 +270,23 @@ SYM_FUNC_END(ftrace_stub_graph)
> */
> SYM_CODE_START(return_to_handler)
> /* save return value regs */
> - sub sp, sp, #64
> - stp x0, x1, [sp]
> - stp x2, x3, [sp, #16]
> - stp x4, x5, [sp, #32]
> - stp x6, x7, [sp, #48]
> + 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
>
> - mov x0, x29 // parent's fp
> - bl ftrace_return_to_handler// addr = ftrace_return_to_hander(fp);
> - mov x30, x0 // restore the original return address
> + mov x0, sp
> + bl ftrace_return_to_handler // addr = ftrace_return_to_hander(regs);
> + mov x30, x0 // restore the original return address
>
> /* restore return value regs */
> - ldp x0, x1, [sp]
> - ldp x2, x3, [sp, #16]
> - ldp x4, x5, [sp, #32]
> - ldp x6, x7, [sp, #48]
> - add sp, sp, #64
> + 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
>
> ret
> SYM_CODE_END(return_to_handler)
> --
> 2.25.1
>