Commit bd28b145 authored by Linus Torvalds's avatar Linus Torvalds

x86: remove more uaccess_32.h complexity

I'm looking at trying to possibly merge the 32-bit and 64-bit versions
of the x86 uaccess.h implementation, but first this needs to be cleaned
up.

For example, the 32-bit version of "__copy_from_user_inatomic()" is
mostly the special cases for the constant size, and it's actually almost
never relevant.  Most users aren't actually using a constant size
anyway, and the few cases that do small constant copies are better off
just using __get_user() instead.

So get rid of the unnecessary complexity.
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5b09c3ed
......@@ -65,32 +65,6 @@ __copy_to_user(void __user *to, const void *from, unsigned long n)
static __always_inline unsigned long
__copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
{
/* Avoid zeroing the tail if the copy fails..
* If 'n' is constant and 1, 2, or 4, we do still zero on a failure,
* but as the zeroing behaviour is only significant when n is not
* constant, that shouldn't be a problem.
*/
if (__builtin_constant_p(n)) {
unsigned long ret;
switch (n) {
case 1:
__uaccess_begin();
__get_user_size(*(u8 *)to, from, 1, ret, 1);
__uaccess_end();
return ret;
case 2:
__uaccess_begin();
__get_user_size(*(u16 *)to, from, 2, ret, 2);
__uaccess_end();
return ret;
case 4:
__uaccess_begin();
__get_user_size(*(u32 *)to, from, 4, ret, 4);
__uaccess_end();
return ret;
}
}
return __copy_from_user_ll_nozero(to, from, n);
}
......
......@@ -1694,8 +1694,7 @@ static int is_trap_at_addr(struct mm_struct *mm, unsigned long vaddr)
int result;
pagefault_disable();
result = __copy_from_user_inatomic(&opcode, (void __user*)vaddr,
sizeof(opcode));
result = __get_user(opcode, (uprobe_opcode_t __user *)vaddr);
pagefault_enable();
if (likely(result == 0))
......
......@@ -729,7 +729,7 @@ static int get_futex_value_locked(u32 *dest, u32 __user *from)
int ret;
pagefault_disable();
ret = __copy_from_user_inatomic(dest, from, sizeof(u32));
ret = __get_user(*dest, from);
pagefault_enable();
return ret ? -EFAULT : 0;
......
......@@ -96,8 +96,7 @@ long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count)
pagefault_disable();
do {
ret = __copy_from_user_inatomic(dst++,
(const void __user __force *)src++, 1);
ret = __get_user(*dst++, (const char __user __force *)src++);
} while (dst[-1] && ret == 0 && src - unsafe_addr < count);
dst[-1] = '\0';
......
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