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powerpc/uaccess: Add unsafe_copy_from_user()

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Use the same approach as unsafe_copy_to_user() but instead call
unsafe_get_user() in a loop.

Signed-off-by: Christopher M. Riedl <cmr@codefail.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210227011259.11992-2-cmr@codefail.de
This commit is contained in:
Christopher M. Riedl 2021-02-26 19:12:50 -06:00 • committed by Michael Ellerman
parent deb9b13eb2
commit 9466c1799f
1 changed files with 21 additions and 0 deletions
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21
arch/powerpc/include/asm/uaccess.h
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@ -486,6 +486,27 @@ user_write_access_begin(const void __user *ptr, size_t len)
#define unsafe_put_user(x, p, e) \
__unsafe_put_user_goto((__typeof__(*(p)))(x), (p), sizeof(*(p)), e)
#define unsafe_copy_from_user(d, s, l, e) \
do { \
u8 *_dst = (u8 *)(d); \
const u8 __user *_src = (const u8 __user *)(s); \
size_t _len = (l); \
int _i; \
\
for (_i = 0; _i < (_len & ~(sizeof(long) - 1)); _i += sizeof(long)) \
unsafe_get_user(*(long *)(_dst + _i), (long __user *)(_src + _i), e); \
if (IS_ENABLED(CONFIG_PPC64) && (_len & 4)) { \
unsafe_get_user(*(u32 *)(_dst + _i), (u32 __user *)(_src + _i), e); \
_i += 4; \
} \
if (_len & 2) { \
unsafe_get_user(*(u16 *)(_dst + _i), (u16 __user *)(_src + _i), e); \
_i += 2; \
} \
if (_len & 1) \
unsafe_get_user(*(u8 *)(_dst + _i), (u8 __user *)(_src + _i), e); \
} while (0)
#define unsafe_copy_to_user(d, s, l, e) \
do { \
u8 __user *_dst = (u8 __user *)(d); \