diff options
| author | Björn Töpel <bjorn.topel@intel.com> | 2021-03-05 10:41:13 +0100 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2021-03-08 08:52:28 -0800 |
| commit | 291471dd1559528a4c2ad5026eff94ed1030562b (patch) | |
| tree | af863fd112a199148f11c746556393b48d9029d7 /tools/lib/bpf/libbpf_util.h | |
| parent | a23b3f5697e6cf8affa7adf3e967e5ab569ea757 (diff) | |
libbpf, xsk: Add libbpf_smp_store_release libbpf_smp_load_acquire
Now that the AF_XDP rings have load-acquire/store-release semantics,
move libbpf to that as well.
The library-internal libbpf_smp_{load_acquire,store_release} are only
valid for 32-bit words on ARM64.
Also, remove the barriers that are no longer in use.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210305094113.413544-3-bjorn.topel@gmail.com
Diffstat (limited to 'tools/lib/bpf/libbpf_util.h')
| -rw-r--r-- | tools/lib/bpf/libbpf_util.h | 72 |
1 files changed, 50 insertions, 22 deletions
diff --git a/tools/lib/bpf/libbpf_util.h b/tools/lib/bpf/libbpf_util.h index 59c779c5790c..94a0d7bb6f3c 100644 --- a/tools/lib/bpf/libbpf_util.h +++ b/tools/lib/bpf/libbpf_util.h @@ -5,6 +5,7 @@ #define __LIBBPF_LIBBPF_UTIL_H #include <stdbool.h> +#include <linux/compiler.h> #ifdef __cplusplus extern "C" { @@ -15,29 +16,56 @@ extern "C" { * application that uses libbpf. */ #if defined(__i386__) || defined(__x86_64__) -# define libbpf_smp_rmb() asm volatile("" : : : "memory") -# define libbpf_smp_wmb() asm volatile("" : : : "memory") -# define libbpf_smp_mb() \ - asm volatile("lock; addl $0,-4(%%rsp)" : : : "memory", "cc") -/* Hinders stores to be observed before older loads. */ -# define libbpf_smp_rwmb() asm volatile("" : : : "memory") +# define libbpf_smp_store_release(p, v) \ + do { \ + asm volatile("" : : : "memory"); \ + WRITE_ONCE(*p, v); \ + } while (0) +# define libbpf_smp_load_acquire(p) \ + ({ \ + typeof(*p) ___p1 = READ_ONCE(*p); \ + asm volatile("" : : : "memory"); \ + ___p1; \ + }) #elif defined(__aarch64__) -# define libbpf_smp_rmb() asm volatile("dmb ishld" : : : "memory") -# define libbpf_smp_wmb() asm volatile("dmb ishst" : : : "memory") -# define libbpf_smp_mb() asm volatile("dmb ish" : : : "memory") -# define libbpf_smp_rwmb() libbpf_smp_mb() -#elif defined(__arm__) -/* These are only valid for armv7 and above */ -# define libbpf_smp_rmb() asm volatile("dmb ish" : : : "memory") -# define libbpf_smp_wmb() asm volatile("dmb ishst" : : : "memory") -# define libbpf_smp_mb() asm volatile("dmb ish" : : : "memory") -# define libbpf_smp_rwmb() libbpf_smp_mb() -#else -/* Architecture missing native barrier functions. */ -# define libbpf_smp_rmb() __sync_synchronize() -# define libbpf_smp_wmb() __sync_synchronize() -# define libbpf_smp_mb() __sync_synchronize() -# define libbpf_smp_rwmb() __sync_synchronize() +# define libbpf_smp_store_release(p, v) \ + asm volatile ("stlr %w1, %0" : "=Q" (*p) : "r" (v) : "memory") +# define libbpf_smp_load_acquire(p) \ + ({ \ + typeof(*p) ___p1; \ + asm volatile ("ldar %w0, %1" \ + : "=r" (___p1) : "Q" (*p) : "memory"); \ + __p1; \ + }) +#elif defined(__riscv) +# define libbpf_smp_store_release(p, v) \ + do { \ + asm volatile ("fence rw,w" : : : "memory"); \ + WRITE_ONCE(*p, v); \ + } while (0) +# define libbpf_smp_load_acquire(p) \ + ({ \ + typeof(*p) ___p1 = READ_ONCE(*p); \ + asm volatile ("fence r,rw" : : : "memory"); \ + ___p1; \ + }) +#endif + +#ifndef libbpf_smp_store_release +#define libbpf_smp_store_release(p, v) \ + do { \ + __sync_synchronize(); \ + WRITE_ONCE(*p, v); \ + } while (0) +#endif + +#ifndef libbpf_smp_load_acquire +#define libbpf_smp_load_acquire(p) \ + ({ \ + typeof(*p) ___p1 = READ_ONCE(*p); \ + __sync_synchronize(); \ + ___p1; \ + }) #endif #ifdef __cplusplus |