[PATCH v1 12/15] powerpc/uaccess: Refactor get/put_user() and __get/put_user()

Christophe Leroy
2021-02-25T17:59:04Z

Make get_user() do the access_ok() check then call __get_user().
Make put_user() do the access_ok() check then call __put_user().

Then embed __get_user_size() and __put_user_size() in
__get_user() and __put_user().

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/include/asm/uaccess.h | 66 +++++++++++-------------------
1 file changed, 23 insertions(+), 43 deletions(-)

diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index 616a3a7928c2..671c083f2f2f 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -43,21 +43,6 @@ static inline bool __access_ok(unsigned long addr, unsigned long size)
* exception handling means that it's no longer "just"...)
*
*/
-#define __put_user_size(x, ptr, size, retval) \
-do { \
- __label__ __pu_failed; \
- \
- retval = 0; \
- allow_write_to_user(ptr, size); \
- __put_user_size_goto(x, ptr, size, __pu_failed); \
- prevent_write_to_user(ptr, size); \
- break; \
- \
-__pu_failed: \
- retval = -EFAULT; \
- prevent_write_to_user(ptr, size); \
-} while (0)
-
#define __put_user(x, ptr) \
({ \
long __pu_err; \
@@ -66,23 +51,29 @@ __pu_failed: \
__typeof__(sizeof(*(ptr))) __pu_size = sizeof(*(ptr)); \
\
might_fault(); \
- __put_user_size(__pu_val, __pu_addr, __pu_size, __pu_err); \
+ do { \
+ __label__ __pu_failed; \
+ \
+ allow_write_to_user(__pu_addr, __pu_size); \
+ __put_user_size_goto(__pu_val, __pu_addr, __pu_size, __pu_failed); \
+ prevent_write_to_user(__pu_addr, __pu_size); \
+ __pu_err = 0; \
+ break; \
+ \
+__pu_failed: \
+ prevent_write_to_user(__pu_addr, __pu_size); \
+ __pu_err = -EFAULT; \
+ } while (0); \
\
__pu_err; \
})

#define put_user(x, ptr) \
({ \
- long __pu_err = -EFAULT; \
- __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
- __typeof__(*(ptr)) __pu_val = (__typeof__(*(ptr)))(x); \
- __typeof__(sizeof(*(ptr))) __pu_size = sizeof(*(ptr)); \
+ __typeof__(*(ptr)) __user *_pu_addr = (ptr); \
\
- might_fault(); \
- if (access_ok(__pu_addr, __pu_size)) \
- __put_user_size(__pu_val, __pu_addr, __pu_size, __pu_err); \
- \
- __pu_err; \
+ access_ok(_pu_addr, sizeof(*(ptr))) ? \
+ __put_user(x, _pu_addr) : -EFAULT; \
})

/*
@@ -192,13 +183,6 @@ do { \
} \
} while (0)

-#define __get_user_size(x, ptr, size, retval) \
-do { \
- allow_read_from_user(ptr, size); \
- __get_user_size_allowed(x, ptr, size, retval); \
- prevent_read_from_user(ptr, size); \
-} while (0)
-
/*
* This is a type: either unsigned long, if the argument fits into
* that type, or otherwise unsigned long long.
@@ -214,7 +198,9 @@ do { \
__typeof__(sizeof(*(ptr))) __gu_size = sizeof(*(ptr)); \
\
might_fault(); \
- __get_user_size(__gu_val, __gu_addr, __gu_size, __gu_err); \
+ allow_read_from_user(__gu_addr, __gu_size); \
+ __get_user_size_allowed(__gu_val, __gu_addr, __gu_size, __gu_err); \
+ prevent_read_from_user(__gu_addr, __gu_size); \
(x) = (__typeof__(*(ptr)))__gu_val; \
\
__gu_err; \
@@ -222,17 +208,11 @@ do { \

#define get_user(x, ptr) \
({ \
- long __gu_err = -EFAULT; \
- __long_type(*(ptr)) __gu_val = 0; \
- __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
- __typeof__(sizeof(*(ptr))) __gu_size = sizeof(*(ptr)); \
- \
- might_fault(); \
- if (access_ok(__gu_addr, __gu_size)) \
- __get_user_size(__gu_val, __gu_addr, __gu_size, __gu_err); \
- (x) = (__force __typeof__(*(ptr)))__gu_val; \
+ __typeof__(*(ptr)) __user *_gu_addr = (ptr); \
\
- __gu_err; \
+ access_ok(_gu_addr, sizeof(*(ptr))) ? \
+ __get_user(x, _gu_addr) : \
+ ((x) = (__force __typeof__(*(ptr)))0, -EFAULT); \
})

/* more complex routines */
--
2.25.0