[PATCH v1 06/15] powerpc/uaccess: Call might_fault() inconditionaly

Christophe Leroy
2021-02-25T17:56:22Z

Commit 6bfd93c32a50 ("powerpc: Fix incorrect might_sleep in
__get_user/__put_user on kernel addresses") added a check to not call
might_sleep() on kernel addresses. This was to enable the use of
__get_user() in the alignment exception handler for any address.

Then commit 95156f0051cb ("lockdep, mm: fix might_fault() annotation")
added a check of the address space in might_fault(), based on
set_fs() logic. But this didn't solve the powerpc alignment exception
case as it didn't call set_fs(KERNEL_DS).

Nowadays, set_fs() is gone, previous patch fixed the alignment
exception handler and __get_user/__put_user are not supposed to be
used anymore to read kernel memory.

Therefore the is_kernel_addr() check has become useless and can be
removed.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/include/asm/uaccess.h | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index eaa828a6a419..c4bbc64758a0 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -77,8 +77,7 @@ __pu_failed: \
__typeof__(*(ptr)) __pu_val = (x); \
__typeof__(size) __pu_size = (size); \
\
- if (!is_kernel_addr((unsigned long)__pu_addr)) \
- might_fault(); \
+ might_fault(); \
__chk_user_ptr(__pu_addr); \
__put_user_size(__pu_val, __pu_addr, __pu_size, __pu_err); \
\
@@ -238,12 +237,12 @@ do { \
__typeof__(size) __gu_size = (size); \
\
__chk_user_ptr(__gu_addr); \
- if (do_allow && !is_kernel_addr((unsigned long)__gu_addr)) \
+ if (do_allow) { \
might_fault(); \
- if (do_allow) \
__get_user_size(__gu_val, __gu_addr, __gu_size, __gu_err); \
- else \
+ } else { \
__get_user_size_allowed(__gu_val, __gu_addr, __gu_size, __gu_err); \
+ } \
(x) = (__typeof__(*(ptr)))__gu_val; \
\
__gu_err; \
--
2.25.0