Commit ed0d9c66 authored Mar 10, 2021 by Christophe Leroy Committed by Michael Ellerman Apr 03, 2021

powerpc/uaccess: Call might_fault() inconditionaly



Commit 6bfd93c3 ("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 95156f00 ("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

parent 111631b5

arch/powerpc/include/asm/uaccess.h

+4 −5

Original line number	Diff line number	Diff line
		@@ -77,7 +77,6 @@ __pu_failed: \
		__typeof__(*(ptr)) __pu_val = (x); \
		__typeof__(size) __pu_size = (size); \
		\
		if (!is_kernel_addr((unsigned long)__pu_addr)) \
		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; \