This reverts commit 3af2ebf798c52b20de827b9dfec13472ab4a7964.
This temporarily reverts the backport of upstream commit
1f001e9da6bbf482311e45e48f53c2bd2179e59c. It was not correct to copy the
ftrace stub as it would contain a relative jump to the return thunk which
would not apply to the context where it was being copied to, leading to
ftrace support to be broken.
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx>
---
arch/x86/kernel/ftrace.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index ceab28277546..5080f578236a 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -309,7 +309,7 @@ union ftrace_op_code_union {
} __attribute__((packed));
};
-#define RET_SIZE (IS_ENABLED(CONFIG_RETPOLINE) ? 5 : 1 + IS_ENABLED(CONFIG_SLS))
+#define RET_SIZE 1 + IS_ENABLED(CONFIG_SLS)
static unsigned long
create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
@@ -368,10 +368,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
/* The trampoline ends with ret(q) */
retq = (unsigned long)ftrace_stub;
- if (cpu_feature_enabled(X86_FEATURE_RETHUNK))
- memcpy(ip, text_gen_insn(JMP32_INSN_OPCODE, ip, &__x86_return_thunk), JMP32_INSN_SIZE);
- else
- ret = copy_from_kernel_nofault(ip, (void *)retq, RET_SIZE);
+ ret = copy_from_kernel_nofault(ip, (void *)retq, RET_SIZE);
if (WARN_ON(ret < 0))
goto fail;
--
2.34.1
