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| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2020-01-24 14:54:43 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-01-28 15:14:40 +0300 |
| commit | bedb4dbe443c11ff551b4ae4e48c8676fdc96467 (patch) | |
| tree | f82b693795ae0089a230efac3f02c01a8ede42f1 /arch/powerpc/include/asm/book3s/64/kup-radix.h | |
| parent | 88f8c080d47f307871840a0a825ef556673eb592 (diff) | |
| download | linux-bedb4dbe443c11ff551b4ae4e48c8676fdc96467.tar.xz | |
powerpc/32s: Prepare prevent_user_access() for user_access_end()
In preparation of implementing user_access_begin and friends
on powerpc, the book3s/32 version of prevent_user_access() need
to be prepared for user_access_end().
user_access_end() doesn't provide the address and size which
were passed to user_access_begin(), required by prevent_user_access()
to know which segment to modify.
The list of segments which where unprotected by allow_user_access()
are available in current->kuap. But we don't want prevent_user_access()
to read this all the time, especially everytime it is 0 (for instance
because the access was not a write access).
Implement a special direction named KUAP_CURRENT. In this case only,
the addr and end are retrieved from current->kuap.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/55bcc1f25d8200892a31f67a0b024ff3b816c3cc.1579866752.git.christophe.leroy@c-s.fr
Diffstat (limited to 'arch/powerpc/include/asm/book3s/64/kup-radix.h')
| -rw-r--r-- | arch/powerpc/include/asm/book3s/64/kup-radix.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/powerpc/include/asm/book3s/64/kup-radix.h b/arch/powerpc/include/asm/book3s/64/kup-radix.h index c8d1076e0ebb..a0263e94df33 100644 --- a/arch/powerpc/include/asm/book3s/64/kup-radix.h +++ b/arch/powerpc/include/asm/book3s/64/kup-radix.h @@ -86,8 +86,10 @@ static __always_inline void allow_user_access(void __user *to, const void __user set_kuap(AMR_KUAP_BLOCK_WRITE); else if (dir == KUAP_WRITE) set_kuap(AMR_KUAP_BLOCK_READ); - else + else if (dir == KUAP_READ_WRITE) set_kuap(0); + else + BUILD_BUG(); } static inline void prevent_user_access(void __user *to, const void __user *from, |