powerpc/uaccess: Don't use "m<>" constraint with GCC 4.9
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:100:2: 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: fcf1f268 ("powerpc/uaccess: Add pre-update addressing to __put_user_asm_goto()") Fixes: 2f279eeb ("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
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