On Thu, 22 Oct 2020 09:29:19 +0000 (UTC), Christophe Leroy wrote:
> 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
>
> [...]
Patches 2-3 applied to powerpc/next.
[2/3] powerpc: Fix incorrect stw{, ux, u, x} instructions in __set_pte_at
https://git.kernel.org/powerpc/c/d85be8a49e733dcd23674aa6202870d54bf5600d
[3/3] powerpc: Fix update form addressing in inline assembly
https://git.kernel.org/powerpc/c/ff57698a9610fcf7d9c4469bf68c881eff22e2f8
cheers
