[PATCH v2 07/18] nios2: drop access_ok() check from __put_user()

Arnd Bergmann
2022-02-16T13:17:22Z

From: Arnd Bergmann <arnd@arndb.de>

Unlike other architectures, the nios2 version of __put_user() has an
extra check for access_ok(), preventing it from being used to implement
__put_kernel_nofault().

Split up put_user() along the same lines as __get_user()/get_user()

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
arch/nios2/include/asm/uaccess.h | 56 +++++++++++++++++++-------------
1 file changed, 33 insertions(+), 23 deletions(-)

diff --git a/arch/nios2/include/asm/uaccess.h b/arch/nios2/include/asm/uaccess.h
index ca9285a915ef..a5cbe07cf0da 100644
--- a/arch/nios2/include/asm/uaccess.h
+++ b/arch/nios2/include/asm/uaccess.h
@@ -167,34 +167,44 @@ do { \
: "r" (val), "r" (ptr), "i" (-EFAULT)); \
}

-#define put_user(x, ptr) \
+#define __put_user_common(__pu_val, __pu_ptr) \
({ \
long __pu_err = -EFAULT; \
- __typeof__(*(ptr)) __user *__pu_ptr = (ptr); \
- __typeof__(*(ptr)) __pu_val = (__typeof(*ptr))(x); \
- if (access_ok(__pu_ptr, sizeof(*__pu_ptr))) { \
- switch (sizeof(*__pu_ptr)) { \
- case 1: \
- __put_user_asm(__pu_val, "stb", __pu_ptr, __pu_err); \
- break; \
- case 2: \
- __put_user_asm(__pu_val, "sth", __pu_ptr, __pu_err); \
- break; \
- case 4: \
- __put_user_asm(__pu_val, "stw", __pu_ptr, __pu_err); \
- break; \
- default: \
- /* XXX: This looks wrong... */ \
- __pu_err = 0; \
- if (copy_to_user(__pu_ptr, &(__pu_val), \
- sizeof(*__pu_ptr))) \
- __pu_err = -EFAULT; \
- break; \
- } \
+ switch (sizeof(*__pu_ptr)) { \
+ case 1: \
+ __put_user_asm(__pu_val, "stb", __pu_ptr, __pu_err); \
+ break; \
+ case 2: \
+ __put_user_asm(__pu_val, "sth", __pu_ptr, __pu_err); \
+ break; \
+ case 4: \
+ __put_user_asm(__pu_val, "stw", __pu_ptr, __pu_err); \
+ break; \
+ default: \
+ /* XXX: This looks wrong... */ \
+ __pu_err = 0; \
+ if (__copy_to_user(__pu_ptr, &(__pu_val), \
+ sizeof(*__pu_ptr))) \
+ __pu_err = -EFAULT; \
+ break; \
} \
__pu_err; \
})

-#define __put_user(x, ptr) put_user(x, ptr)
+#define __put_user(x, ptr) \
+({ \
+ __auto_type __pu_ptr = (ptr); \
+ typeof(*__pu_ptr) __pu_val = (typeof(*__pu_ptr))(x); \
+ __put_user_common(__pu_val, __pu_ptr); \
+})
+
+#define put_user(x, ptr) \
+({ \
+ __auto_type __pu_ptr = (ptr); \
+ typeof(*__pu_ptr) __pu_val = (typeof(*__pu_ptr))(x); \
+ access_ok(__pu_ptr, sizeof(*__pu_ptr)) ? \
+ __put_user_common(__pu_val, __pu_ptr) : \
+ -EFAULT; \
+})

#endif /* _ASM_NIOS2_UACCESS_H */
--
2.29.2