From bb85d206be208bbf834883e948125a35ac59993a Mon Sep 17 00:00:00 2001
From: Chenghao Duan <duanchenghao@kylinos.cn>
Date: Wed, 31 Dec 2025 15:19:25 +0800
Subject: [PATCH] samples/ftrace: Adjust LoongArch register restore order in
 direct calls

Ensure that in the ftrace direct call logic, the CPU register state
(with ra = parent return address) is restored to the correct state after
the execution of the custom trampoline function and before returning to
the traced function. Additionally, guarantee the correctness of the jump
logic for jr t0 (traced function address).

Cc: stable@vger.kernel.org
Fixes: 9cdc3b6a299c ("LoongArch: ftrace: Add direct call support")
Reported-by: Youling Tang <tangyouling@kylinos.cn>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Chenghao Duan <duanchenghao@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
 samples/ftrace/ftrace-direct-modify.c       | 8 ++++----
 samples/ftrace/ftrace-direct-multi-modify.c | 8 ++++----
 samples/ftrace/ftrace-direct-multi.c        | 4 ++--
 samples/ftrace/ftrace-direct-too.c          | 4 ++--
 samples/ftrace/ftrace-direct.c              | 4 ++--
 5 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c
index da3a9f2091f5..1ba1927b548e 100644
--- a/samples/ftrace/ftrace-direct-modify.c
+++ b/samples/ftrace/ftrace-direct-modify.c
@@ -176,8 +176,8 @@ asm (
 "	st.d	$t0, $sp, 0\n"
 "	st.d	$ra, $sp, 8\n"
 "	bl	my_direct_func1\n"
-"	ld.d	$t0, $sp, 0\n"
-"	ld.d	$ra, $sp, 8\n"
+"	ld.d	$ra, $sp, 0\n"
+"	ld.d	$t0, $sp, 8\n"
 "	addi.d	$sp, $sp, 16\n"
 "	jr	$t0\n"
 "	.size		my_tramp1, .-my_tramp1\n"
@@ -189,8 +189,8 @@ asm (
 "	st.d	$t0, $sp, 0\n"
 "	st.d	$ra, $sp, 8\n"
 "	bl	my_direct_func2\n"
-"	ld.d	$t0, $sp, 0\n"
-"	ld.d	$ra, $sp, 8\n"
+"	ld.d	$ra, $sp, 0\n"
+"	ld.d	$t0, $sp, 8\n"
 "	addi.d	$sp, $sp, 16\n"
 "	jr	$t0\n"
 "	.size		my_tramp2, .-my_tramp2\n"
diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c
index 8f7986d698d8..7a7822dfeb50 100644
--- a/samples/ftrace/ftrace-direct-multi-modify.c
+++ b/samples/ftrace/ftrace-direct-multi-modify.c
@@ -199,8 +199,8 @@ asm (
 "	move	$a0, $t0\n"
 "	bl	my_direct_func1\n"
 "	ld.d	$a0, $sp, 0\n"
-"	ld.d	$t0, $sp, 8\n"
-"	ld.d	$ra, $sp, 16\n"
+"	ld.d	$ra, $sp, 8\n"
+"	ld.d	$t0, $sp, 16\n"
 "	addi.d	$sp, $sp, 32\n"
 "	jr	$t0\n"
 "	.size		my_tramp1, .-my_tramp1\n"
@@ -215,8 +215,8 @@ asm (
 "	move	$a0, $t0\n"
 "	bl	my_direct_func2\n"
 "	ld.d	$a0, $sp, 0\n"
-"	ld.d	$t0, $sp, 8\n"
-"	ld.d	$ra, $sp, 16\n"
+"	ld.d	$ra, $sp, 8\n"
+"	ld.d	$t0, $sp, 16\n"
 "	addi.d	$sp, $sp, 32\n"
 "	jr	$t0\n"
 "	.size		my_tramp2, .-my_tramp2\n"
diff --git a/samples/ftrace/ftrace-direct-multi.c b/samples/ftrace/ftrace-direct-multi.c
index db326c81a27d..3fe6ddaf0b69 100644
--- a/samples/ftrace/ftrace-direct-multi.c
+++ b/samples/ftrace/ftrace-direct-multi.c
@@ -131,8 +131,8 @@ asm (
 "	move	$a0, $t0\n"
 "	bl	my_direct_func\n"
 "	ld.d	$a0, $sp, 0\n"
-"	ld.d	$t0, $sp, 8\n"
-"	ld.d	$ra, $sp, 16\n"
+"	ld.d	$ra, $sp, 8\n"
+"	ld.d	$t0, $sp, 16\n"
 "	addi.d	$sp, $sp, 32\n"
 "	jr	$t0\n"
 "	.size		my_tramp, .-my_tramp\n"
diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c
index 3d0fa260332d..bf2411aa6fd7 100644
--- a/samples/ftrace/ftrace-direct-too.c
+++ b/samples/ftrace/ftrace-direct-too.c
@@ -143,8 +143,8 @@ asm (
 "	ld.d	$a0, $sp, 0\n"
 "	ld.d	$a1, $sp, 8\n"
 "	ld.d	$a2, $sp, 16\n"
-"	ld.d	$t0, $sp, 24\n"
-"	ld.d	$ra, $sp, 32\n"
+"	ld.d	$ra, $sp, 24\n"
+"	ld.d	$t0, $sp, 32\n"
 "	addi.d	$sp, $sp, 48\n"
 "	jr	$t0\n"
 "	.size		my_tramp, .-my_tramp\n"
diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c
index 956834b0d19a..5368c8c39cbb 100644
--- a/samples/ftrace/ftrace-direct.c
+++ b/samples/ftrace/ftrace-direct.c
@@ -124,8 +124,8 @@ asm (
 "	st.d	$ra, $sp, 16\n"
 "	bl	my_direct_func\n"
 "	ld.d	$a0, $sp, 0\n"
-"	ld.d	$t0, $sp, 8\n"
-"	ld.d	$ra, $sp, 16\n"
+"	ld.d	$ra, $sp, 8\n"
+"	ld.d	$t0, $sp, 16\n"
 "	addi.d	$sp, $sp, 32\n"
 "	jr	$t0\n"
 "	.size		my_tramp, .-my_tramp\n"