[RFC PATCH 22/22] riscv: s64ilp32: Temporary workaround solution to gcc problem

From: guoren
Date: Thu May 18 2023 - 09:16:49 EST


From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>

There is an existing problem in 64ilp32 gcc that combines two pointers
in one register. Liao is solving that problem. Before he finishes the
job, we could prevent it with a simple noinline attribute, fortunately.

struct path {
struct vfsmount *mnt;
struct dentry *dentry;
} __randomize_layout;

struct nameidata {
struct path path;
struct qstr last;
struct path root;
...
} __randomize_layout;

struct nameidata *nd
...
nd->path = nd->root;
6c88 ld a0,24(s1)
^^ // Wrong arg of mntget
e088 sd a0,0(s1)
// Need inserting "lw a0,0(s1)" here
mntget(path->mnt);
2a6150ef jal c01ce946 <mntget>

Any gcc helps are welcome :)

Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Signed-off-by: Guo Ren <guoren@xxxxxxxxxx>
Cc: LiaoShihua <shihua@xxxxxxxxxxx>
---
fs/namei.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/namei.c b/fs/namei.c
index edfedfbccaef..22a2ef77e074 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -541,7 +541,7 @@ EXPORT_SYMBOL(inode_permission);
*
* Given a path increment the reference count to the dentry and the vfsmount.
*/
-void path_get(const struct path *path)
+void noinline path_get(const struct path *path)
{
mntget(path->mnt);
dget(path->dentry);
--
2.36.1