Re: arm64 tools build failure wrt smp_load_{acquire,release} expansion on gcc version 5.4.0 20160609 (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.9)
From: Arnaldo Carvalho de Melo
Date: Wed Oct 31 2018 - 17:15:04 EST
Em Wed, Oct 31, 2018 at 07:08:29PM +0100, Daniel Borkmann escreveu:
> On 10/31/2018 06:44 PM, Will Deacon wrote:
> > Diff below...
> I just gave this a spin on 16.04 and it resolves the build issue, thanks
> for the quick fix, Will!
> Tested-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
It buildz, ship it:
# 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
#
So I've added it to my tree as below, can I keep it like that?
Thanks,
- Arnaldo
commit 86b21876a75c912917ade1e2b3831501eb2e9e45
Author: Will Deacon <will.deacon@xxxxxxx>
Date: Wed Oct 31 17:44:08 2018 +0000
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.
Reported-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Tested-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20181031174408.GA27871@xxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
diff --git a/tools/arch/arm64/include/asm/barrier.h b/tools/arch/arm64/include/asm/barrier.h
index 12835ea0e417..378c051fa177 100644
--- a/tools/arch/arm64/include/asm/barrier.h
+++ b/tools/arch/arm64/include/asm/barrier.h
@@ -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 */