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s390/uaccess: Add copy_from/to_user_key functions

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Add copy_from/to_user_key functions, which perform storage key checking.
These functions can be used by KVM for emulating instructions that need
to be key checked.
These functions differ from their non _key counterparts in
include/linux/uaccess.h only in the additional key argument and must be
kept in sync with those.

Since the existing uaccess implementation on s390 makes use of move
instructions that support having an additional access key supplied,
we can implement raw_copy_from/to_user_key by enhancing the
existing implementation.

Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20220211182215.2730017-2-scgl@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
This commit is contained in:
Janis Schoetterl-Glausch
2022-02-11 19:22:06 +01:00
committed by Christian Borntraeger
parent bfced9f963
commit 1a82f6ab23
2 changed files with 85 additions and 18 deletions
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22
arch/s390/include/asm/uaccess.h
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@@ -44,6 +44,28 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long n);
#define INLINE_COPY_TO_USER
#endif
unsigned long __must_check
_copy_from_user_key(void *to, const void __user *from, unsigned long n, unsigned long key);
static __always_inline unsigned long __must_check
copy_from_user_key(void *to, const void __user *from, unsigned long n, unsigned long key)
{
if (likely(check_copy_size(to, n, false)))
n = _copy_from_user_key(to, from, n, key);
return n;
}
unsigned long __must_check
_copy_to_user_key(void __user *to, const void *from, unsigned long n, unsigned long key);
static __always_inline unsigned long __must_check
copy_to_user_key(void __user *to, const void *from, unsigned long n, unsigned long key)
{
if (likely(check_copy_size(from, n, true)))
n = _copy_to_user_key(to, from, n, key);
return n;
}
int __put_user_bad(void) __attribute__((noreturn));
int __get_user_bad(void) __attribute__((noreturn));