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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/kup.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/kup.h')
| -rw-r--r-- | arch/powerpc/include/asm/kup.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h index 94f24928916a..c3ce7e8ae9ea 100644 --- a/arch/powerpc/include/asm/kup.h +++ b/arch/powerpc/include/asm/kup.h @@ -5,6 +5,12 @@ #define KUAP_READ 1 #define KUAP_WRITE 2 #define KUAP_READ_WRITE (KUAP_READ | KUAP_WRITE) +/* + * For prevent_user_access() only. + * Use the current saved situation instead of the to/from/size params. + * Used on book3s/32 + */ +#define KUAP_CURRENT 4 #ifdef CONFIG_PPC64 #include <asm/book3s/64/kup-radix.h> @@ -88,6 +94,11 @@ static inline void prevent_read_write_user(void __user *to, const void __user *f prevent_user_access(to, from, size, KUAP_READ_WRITE); } +static inline void prevent_current_access_user(void) +{ + prevent_user_access(NULL, NULL, ~0UL, KUAP_CURRENT); +} + #endif /* !__ASSEMBLY__ */ #endif /* _ASM_POWERPC_KUAP_H_ */ |