powerpc/uaccess: Call might_fault() inconditionaly

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>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/e0a980a4dc7a2551183dd5cb30f46eafdbee390c.1615398265.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index 8b81535e68d49cee6ca198228de680db8f859746..ce3dc3f407ac7388f78e331de73dc975a7cf64d5 100644 (file)
--- 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;                                               \