[PATCH v7 4/8] arm64: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL
Donglin Peng
pengdonglin at sangfor.com.cn
Fri Mar 24 05:37:27 PDT 2023
The commit d4815c5d1bbd ("function_graph: Support recording and
printing the return value of function") 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 <pengdonglin at sangfor.com.cn>
---
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/ftrace.h | 23 +++++++++++++++++++++++
arch/arm64/kernel/entry-ftrace.S | 9 +++++----
3 files changed, 29 insertions(+), 4 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..f68dcc41be3b 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -170,4 +170,27 @@ static inline bool arch_syscall_match_sym_name(const char *sym,
}
#endif /* ifndef __ASSEMBLY__ */
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_HAVE_FUNCTION_GRAPH_RETVAL
+struct fgraph_ret_regs {
+ /* x0 - x7 */
+ u64 regs[8];
+
+ u64 fp;
+};
+
+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
+
#endif /* __ASM_FTRACE_H */
diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S
index 350ed81324ac..8ac6f952e68f 100644
--- a/arch/arm64/kernel/entry-ftrace.S
+++ b/arch/arm64/kernel/entry-ftrace.S
@@ -270,14 +270,15 @@ SYM_FUNC_END(ftrace_stub_graph)
*/
SYM_CODE_START(return_to_handler)
/* save return value regs */
- sub sp, sp, #64
+ sub sp, sp, #72
stp x0, x1, [sp]
stp x2, x3, [sp, #16]
stp x4, x5, [sp, #32]
stp x6, x7, [sp, #48]
+ str x29, [sp, #64] // parent's fp
- mov x0, x29 // parent's fp
- bl ftrace_return_to_handler// addr = ftrace_return_to_hander(fp);
+ 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 */
@@ -285,7 +286,7 @@ SYM_CODE_START(return_to_handler)
ldp x2, x3, [sp, #16]
ldp x4, x5, [sp, #32]
ldp x6, x7, [sp, #48]
- add sp, sp, #64
+ add sp, sp, #72
ret
SYM_CODE_END(return_to_handler)
--
2.25.1
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