LoongArch: Refactor register restoration in ftrace_common_return

Browse source

commit 45cb47c628 upstream.

Refactor the register restoration sequence in the ftrace_common_return
function to clearly distinguish between the logic of normal returns and
direct call returns in function tracing scenarios. The logic is as
follows:

1. In the case of a normal return, the execution flow returns to the
traced function, and ftrace must ensure that the register data is
consistent with the state when the function was entered.

ra = parent return address; t0 = traced function return address.

2. In the case of a direct call return, the execution flow jumps to the
custom trampoline function, and ftrace must ensure that the register
data is consistent with the state when ftrace was entered.

ra = traced function return address; t0 = parent return address.

Cc: stable@vger.kernel.org
Fixes: 9cdc3b6a29 ("LoongArch: ftrace: Add direct call support")
Signed-off-by: Chenghao Duan <duanchenghao@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Chenghao Duan 2025-12-31 15:19:20 +08:00 • committed by Greg Kroah-Hartman

parent 73feae0c71

commit bb92a3af3c

1 changed files with 10 additions and 4 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

14

arch/loongarch/kernel/mcount_dyn.S

View file