Commit de4ffc65 authored by Michael Ellerman's avatar Michael Ellerman
Browse files

powerpc/uaccess: Simplify unsafe_put_user() implementation 



Currently unsafe_put_user() expands to __put_user_goto(), which
expands to __put_user_nocheck_goto().

There are no other uses of __put_user_nocheck_goto(), and although
there are some other uses of __put_user_goto() those could just use
unsafe_put_user().

Every layer of indirection introduces the possibility that some code
is calling that layer, and makes keeping track of the required
semantics at each point more complicated.

So drop __put_user_goto(), and rename __put_user_nocheck_goto() to
__unsafe_put_user_goto(). The "nocheck" is implied by "unsafe".

Replace the few uses of __put_user_goto() with unsafe_put_user().

Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210208135717.2618798-1-mpe@ellerman.id.au
parent f30520c6

arch/powerpc/include/asm/uaccess.h

+7 −8
Original line number Diff line number Diff line
@@ -52,8 +52,6 @@ static inline bool __access_ok(unsigned long addr, unsigned long size) 
	__get_user_nocheck((x), (ptr), sizeof(*(ptr)), true)

#define __put_user(x, ptr) \

	__put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))

#define __put_user_goto(x, ptr, label) \

	__put_user_nocheck_goto((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)), label)



#define __get_user_allowed(x, ptr) \

	__get_user_nocheck((x), (ptr), sizeof(*(ptr)), false)
@@ -213,7 +211,7 @@ do { \ 
	}							\

} while (0)



#define __put_user_nocheck_goto(x, ptr, size, label)		\

#define __unsafe_put_user_goto(x, ptr, size, label)		\

do {								\

	__typeof__(*(ptr)) __user *__pu_addr = (ptr);		\

	if (!is_kernel_addr((unsigned long)__pu_addr))		\
@@ -530,7 +528,8 @@ user_write_access_begin(const void __user *ptr, size_t len) 


#define unsafe_op_wrap(op, err) do { if (unlikely(op)) goto err; } while (0)

#define unsafe_get_user(x, p, e) unsafe_op_wrap(__get_user_allowed(x, p), e)

#define unsafe_put_user(x, p, e) __put_user_goto(x, p, e)

#define unsafe_put_user(x, p, e) \

	__unsafe_put_user_goto((__typeof__(*(p)))(x), (p), sizeof(*(p)), e)



#define unsafe_copy_to_user(d, s, l, e) \

do {									\
@@ -540,17 +539,17 @@ do { \ 
	int _i;								\

									\

	for (_i = 0; _i < (_len & ~(sizeof(long) - 1)); _i += sizeof(long))		\

		__put_user_goto(*(long*)(_src + _i), (long __user *)(_dst + _i), e);\

		unsafe_put_user(*(long*)(_src + _i), (long __user *)(_dst + _i), e); \

	if (IS_ENABLED(CONFIG_PPC64) && (_len & 4)) {			\

		__put_user_goto(*(u32*)(_src + _i), (u32 __user *)(_dst + _i), e);	\

		unsafe_put_user(*(u32*)(_src + _i), (u32 __user *)(_dst + _i), e); \

		_i += 4;						\

	}								\

	if (_len & 2) {							\

		__put_user_goto(*(u16*)(_src + _i), (u16 __user *)(_dst + _i), e);	\

		unsafe_put_user(*(u16*)(_src + _i), (u16 __user *)(_dst + _i), e); \

		_i += 2;						\

	}								\

	if (_len & 1) \

		__put_user_goto(*(u8*)(_src + _i), (u8 __user *)(_dst + _i), e);\

		unsafe_put_user(*(u8*)(_src + _i), (u8 __user *)(_dst + _i), e); \

} while (0)



#define HAVE_GET_KERNEL_NOFAULT