GCC 4.9 sometimes fails to build with "m<>" constraint in
inline assembly.
CC lib/iov_iter.o
In file included from ./arch/powerpc/include/asm/cmpxchg.h:6:0,
from ./arch/powerpc/include/asm/atomic.h:11,
from ./include/linux/atomic.h:7,
from ./include/linux/crypto.h:15,
from ./include/crypto/hash.h:11,
from lib/iov_iter.c:2:
lib/iov_iter.c: In function 'iovec_from_user.part.30':
./arch/powerpc/include/asm/uaccess.h:287:2: error: 'asm' operand has impossible constraints
__asm__ __volatile__( \
^
./include/linux/compiler.h:78:42: note: in definition of macro 'unlikely'
# define unlikely(x) __builtin_expect(!!(x), 0)
^
./arch/powerpc/include/asm/uaccess.h:583:34: note: in expansion of macro 'unsafe_op_wrap'
#define unsafe_get_user(x, p, e) unsafe_op_wrap(__get_user_allowed(x, p), e)
^
./arch/powerpc/include/asm/uaccess.h:329:10: note: in expansion of macro '__get_user_asm'
case 4: __get_user_asm(x, (u32 __user *)ptr, retval, "lwz"); break; \
^
./arch/powerpc/include/asm/uaccess.h:363:3: note: in expansion of macro '__get_user_size_allowed'
__get_user_size_allowed(__gu_val, __gu_addr, __gu_size, __gu_err); \
^
./arch/powerpc/include/asm/uaccess.h💯2: note: in expansion of macro '__get_user_nocheck'
__get_user_nocheck((x), (ptr), sizeof(*(ptr)), false)
^
./arch/powerpc/include/asm/uaccess.h:583:49: note: in expansion of macro '__get_user_allowed'
#define unsafe_get_user(x, p, e) unsafe_op_wrap(__get_user_allowed(x, p), e)
^
lib/iov_iter.c:1663:3: note: in expansion of macro 'unsafe_get_user'
unsafe_get_user(len, &uiov[i].iov_len, uaccess_end);
^
make[1]: *** [scripts/Makefile.build:283: lib/iov_iter.o] Error 1
Define a UPD_CONSTR macro that is "<>" by default and
only "" with GCC prior to GCC 5.
Fixes: fcf1f26895 ("powerpc/uaccess: Add pre-update addressing to __put_user_asm_goto()")
Fixes: 2f279eeb68 ("powerpc/uaccess: Add pre-update addressing to __get_user_asm() and __put_user_asm()")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/212d3bc4a52ca71523759517bb9c61f7e477c46a.1603179582.git.christophe.leroy@csgroup.eu
This patch moves ASM_CONST() and stringify_in_c() into
dedicated asm-const.h, then cleans all related inclusions.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: asm-compat.h should include asm-const.h]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Christophe Leroy