diff options
author | Brendan Jackman <jackmanb@google.com> | 2021-01-14 21:17:46 +0300 |
---|---|---|
committer | Alexei Starovoitov <ast@kernel.org> | 2021-01-15 05:34:29 +0300 |
commit | 5ca419f2864a2c60940dcf4bbaeb69546200e36f (patch) | |
tree | edd181e67503cb404dfa55cfaae6d757db3e22b6 /tools/include | |
parent | c5bcb5eb4db632280b4123135d583a7bc8caea3e (diff) | |
download | linux-5ca419f2864a2c60940dcf4bbaeb69546200e36f.tar.xz |
bpf: Add BPF_FETCH field / create atomic_fetch_add instruction
The BPF_FETCH field can be set in bpf_insn.imm, for BPF_ATOMIC
instructions, in order to have the previous value of the
atomically-modified memory location loaded into the src register
after an atomic op is carried out.
Suggested-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210114181751.768687-7-jackmanb@google.com
Diffstat (limited to 'tools/include')
-rw-r--r-- | tools/include/linux/filter.h | 1 | ||||
-rw-r--r-- | tools/include/uapi/linux/bpf.h | 3 |
2 files changed, 4 insertions, 0 deletions
diff --git a/tools/include/linux/filter.h b/tools/include/linux/filter.h index e870c9039f0d..7211ce9fba53 100644 --- a/tools/include/linux/filter.h +++ b/tools/include/linux/filter.h @@ -173,6 +173,7 @@ * Atomic operations: * * BPF_ADD *(uint *) (dst_reg + off16) += src_reg + * BPF_ADD | BPF_FETCH src_reg = atomic_fetch_add(dst_reg + off16, src_reg); */ #define BPF_ATOMIC_OP(SIZE, OP, DST, SRC, OFF) \ diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 6b3996343e63..ea262b009049 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -44,6 +44,9 @@ #define BPF_CALL 0x80 /* function call */ #define BPF_EXIT 0x90 /* function return */ +/* atomic op type fields (stored in immediate) */ +#define BPF_FETCH 0x01 /* fetch previous value into src reg */ + /* Register numbers */ enum { BPF_REG_0 = 0, |