tools headers barrier: Fix arm64 tools build failure wrt smp_load_{acquire,release}

Cheers for reporting this. I managed to reproduce the build failure with
gcc version 6.3.0 20170516 (Debian 6.3.0-18+deb9u1).

The code in question is the arm64 versions of smp_load_acquire() and
smp_store_release(). Unlike other architectures, these are not built
around READ_ONCE() and WRITE_ONCE() since we have instructions we can
use instead of fences. Bringing our macros up-to-date with those (i.e.
tweaking the union initialisation and using the special "uXX_alias_t"
types) appears to fix the issue for me.

Committer notes:

Testing it in the systems previously failing:

  # time dm android-ndk:r12b-arm \
         android-ndk:r15c-arm \
         debian:experimental-x-arm64 \
         ubuntu:14.04.4-x-linaro-arm64 \
         ubuntu:16.04-x-arm \
         ubuntu:16.04-x-arm64 \
         ubuntu:18.04-x-arm \
         ubuntu:18.04-x-arm64
    1 android-ndk:r12b-arm          : Ok   arm-linux-androideabi-gcc (GCC) 4.9.x 20150123 (prerelease)
    2 android-ndk:r15c-arm          : Ok   arm-linux-androideabi-gcc (GCC) 4.9.x 20150123 (prerelease)
    3 debian:experimental-x-arm64   : Ok   aarch64-linux-gnu-gcc (Debian 8.2.0-7) 8.2.0
    4 ubuntu:14.04.4-x-linaro-arm64 : Ok   aarch64-linux-gnu-gcc (Linaro GCC 5.5-2017.10) 5.5.0
    5 ubuntu:16.04-x-arm            : Ok   arm-linux-gnueabihf-gcc (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
    6 ubuntu:16.04-x-arm64          : Ok   aarch64-linux-gnu-gcc (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
    7 ubuntu:18.04-x-arm            : Ok   arm-linux-gnueabihf-gcc (Ubuntu/Linaro 7.3.0-27ubuntu1~18.04) 7.3.0
    8 ubuntu:18.04-x-arm64          : Ok   aarch64-linux-gnu-gcc (Ubuntu/Linaro 7.3.0-27ubuntu1~18.04) 7.3.0

Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20181031174408.GA27871@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Will Deacon 2018-10-31 17:44:08 +00:00 committed by Arnaldo Carvalho de Melo
parent 29995d296e
commit 51f5fd2e46

View File

@ -14,74 +14,75 @@
#define wmb() asm volatile("dmb ishst" ::: "memory")
#define rmb() asm volatile("dmb ishld" ::: "memory")
#define smp_store_release(p, v) \
do { \
union { typeof(*p) __val; char __c[1]; } __u = \
{ .__val = (__force typeof(*p)) (v) }; \
\
switch (sizeof(*p)) { \
case 1: \
asm volatile ("stlrb %w1, %0" \
: "=Q" (*p) \
: "r" (*(__u8 *)__u.__c) \
: "memory"); \
break; \
case 2: \
asm volatile ("stlrh %w1, %0" \
: "=Q" (*p) \
: "r" (*(__u16 *)__u.__c) \
: "memory"); \
break; \
case 4: \
asm volatile ("stlr %w1, %0" \
: "=Q" (*p) \
: "r" (*(__u32 *)__u.__c) \
: "memory"); \
break; \
case 8: \
asm volatile ("stlr %1, %0" \
: "=Q" (*p) \
: "r" (*(__u64 *)__u.__c) \
: "memory"); \
break; \
default: \
/* Only to shut up gcc ... */ \
mb(); \
break; \
} \
#define smp_store_release(p, v) \
do { \
union { typeof(*p) __val; char __c[1]; } __u = \
{ .__val = (v) }; \
\
switch (sizeof(*p)) { \
case 1: \
asm volatile ("stlrb %w1, %0" \
: "=Q" (*p) \
: "r" (*(__u8_alias_t *)__u.__c) \
: "memory"); \
break; \
case 2: \
asm volatile ("stlrh %w1, %0" \
: "=Q" (*p) \
: "r" (*(__u16_alias_t *)__u.__c) \
: "memory"); \
break; \
case 4: \
asm volatile ("stlr %w1, %0" \
: "=Q" (*p) \
: "r" (*(__u32_alias_t *)__u.__c) \
: "memory"); \
break; \
case 8: \
asm volatile ("stlr %1, %0" \
: "=Q" (*p) \
: "r" (*(__u64_alias_t *)__u.__c) \
: "memory"); \
break; \
default: \
/* Only to shut up gcc ... */ \
mb(); \
break; \
} \
} while (0)
#define smp_load_acquire(p) \
({ \
union { typeof(*p) __val; char __c[1]; } __u; \
\
switch (sizeof(*p)) { \
case 1: \
asm volatile ("ldarb %w0, %1" \
: "=r" (*(__u8 *)__u.__c) \
: "Q" (*p) : "memory"); \
break; \
case 2: \
asm volatile ("ldarh %w0, %1" \
: "=r" (*(__u16 *)__u.__c) \
: "Q" (*p) : "memory"); \
break; \
case 4: \
asm volatile ("ldar %w0, %1" \
: "=r" (*(__u32 *)__u.__c) \
: "Q" (*p) : "memory"); \
break; \
case 8: \
asm volatile ("ldar %0, %1" \
: "=r" (*(__u64 *)__u.__c) \
: "Q" (*p) : "memory"); \
break; \
default: \
/* Only to shut up gcc ... */ \
mb(); \
break; \
} \
__u.__val; \
#define smp_load_acquire(p) \
({ \
union { typeof(*p) __val; char __c[1]; } __u = \
{ .__c = { 0 } }; \
\
switch (sizeof(*p)) { \
case 1: \
asm volatile ("ldarb %w0, %1" \
: "=r" (*(__u8_alias_t *)__u.__c) \
: "Q" (*p) : "memory"); \
break; \
case 2: \
asm volatile ("ldarh %w0, %1" \
: "=r" (*(__u16_alias_t *)__u.__c) \
: "Q" (*p) : "memory"); \
break; \
case 4: \
asm volatile ("ldar %w0, %1" \
: "=r" (*(__u32_alias_t *)__u.__c) \
: "Q" (*p) : "memory"); \
break; \
case 8: \
asm volatile ("ldar %0, %1" \
: "=r" (*(__u64_alias_t *)__u.__c) \
: "Q" (*p) : "memory"); \
break; \
default: \
/* Only to shut up gcc ... */ \
mb(); \
break; \
} \
__u.__val; \
})
#endif /* _TOOLS_LINUX_ASM_AARCH64_BARRIER_H */