diff mbox series

[bpf-next] samples/bpf: add BPF_ATOMIC_OP macro for BPF samples

Message ID 20210118091753.107572-1-bjorn.topel@gmail.com (mailing list archive)
State Accepted
Commit af6953b633b324e6cc24f0bf57ba03505a9c0e29
Delegated to: BPF
Headers show
Series [bpf-next] samples/bpf: add BPF_ATOMIC_OP macro for BPF samples | expand

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Commit Message

Björn Töpel Jan. 18, 2021, 9:17 a.m. UTC 
From: Björn Töpel <bjorn.topel@intel.com>

Brendan Jackman added extend atomic operations to the BPF instruction
set in commit 7064a7341a0d ("Merge branch 'Atomics for eBPF'"), which
introduces the BPF_ATOMIC_OP macro. However, that macro was missing
for the BPF samples. Fix that by adding it into bpf_insn.h.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
---
 samples/bpf/bpf_insn.h | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)


base-commit: 232164e041e925a920bfd28e63d5233cfad90b73

Comments

Brendan Jackman Jan. 18, 2021, 10:57 a.m. UTC | #1 
I actually deliberately skipped this file, thinking that people were
unlikely to want to add assembly-based atomics code under samples/

I guess it's nice for people to be able to e.g. move/copy code from
the selftests.

On Mon, 18 Jan 2021 at 10:18, Björn Töpel <bjorn.topel@gmail.com> wrote:
>
> From: Björn Töpel <bjorn.topel@intel.com>
>
> Brendan Jackman added extend atomic operations to the BPF instruction
> set in commit 7064a7341a0d ("Merge branch 'Atomics for eBPF'"), which
> introduces the BPF_ATOMIC_OP macro. However, that macro was missing
> for the BPF samples. Fix that by adding it into bpf_insn.h.
>
> Signed-off-by: Björn Töpel <bjorn.topel@intel.com>

Reviewed-by: Brendan Jackman <jackmanb@google.com>

> ---
>  samples/bpf/bpf_insn.h | 24 ++++++++++++++++++++----
>  1 file changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/samples/bpf/bpf_insn.h b/samples/bpf/bpf_insn.h
> index db67a2847395..aee04534483a 100644
> --- a/samples/bpf/bpf_insn.h
> +++ b/samples/bpf/bpf_insn.h
> @@ -134,15 +134,31 @@ struct bpf_insn;
>                 .off   = OFF,                                   \
>                 .imm   = 0 })
>
> -/* Atomic memory add, *(uint *)(dst_reg + off16) += src_reg */
> -
> -#define BPF_STX_XADD(SIZE, DST, SRC, OFF)                      \
> +/*
> + * Atomic operations:
> + *
> + *   BPF_ADD                  *(uint *) (dst_reg + off16) += src_reg
> + *   BPF_AND                  *(uint *) (dst_reg + off16) &= src_reg
> + *   BPF_OR                   *(uint *) (dst_reg + off16) |= src_reg
> + *   BPF_XOR                  *(uint *) (dst_reg + off16) ^= src_reg
> + *   BPF_ADD | BPF_FETCH      src_reg = atomic_fetch_add(dst_reg + off16, src_reg);
> + *   BPF_AND | BPF_FETCH      src_reg = atomic_fetch_and(dst_reg + off16, src_reg);
> + *   BPF_OR | BPF_FETCH       src_reg = atomic_fetch_or(dst_reg + off16, src_reg);
> + *   BPF_XOR | BPF_FETCH      src_reg = atomic_fetch_xor(dst_reg + off16, src_reg);
> + *   BPF_XCHG                 src_reg = atomic_xchg(dst_reg + off16, src_reg)
> + *   BPF_CMPXCHG              r0 = atomic_cmpxchg(dst_reg + off16, r0, src_reg)
> + */
> +
> +#define BPF_ATOMIC_OP(SIZE, OP, DST, SRC, OFF)                 \
>         ((struct bpf_insn) {                                    \
>                 .code  = BPF_STX | BPF_SIZE(SIZE) | BPF_ATOMIC, \
>                 .dst_reg = DST,                                 \
>                 .src_reg = SRC,                                 \
>                 .off   = OFF,                                   \
> -               .imm   = BPF_ADD })
> +               .imm   = OP })
> +
> +/* Legacy alias */
> +#define BPF_STX_XADD(SIZE, DST, SRC, OFF) BPF_ATOMIC_OP(SIZE, BPF_ADD, DST, SRC, OFF)
>
>  /* Memory store, *(uint *) (dst_reg + off16) = imm32 */
>
>
> base-commit: 232164e041e925a920bfd28e63d5233cfad90b73
> --
> 2.27.0
>
Björn Töpel Jan. 18, 2021, 11 a.m. UTC | #2 
On 2021-01-18 11:57, Brendan Jackman wrote:
> I actually deliberately skipped this file, thinking that people were
> unlikely to want to add assembly-based atomics code under samples/
> 
> I guess it's nice for people to be able to e.g. move/copy code from
> the selftests.
>

Yes, that, and the fact that one sample broke w/o the BPF_ATOMIC_OP.


> On Mon, 18 Jan 2021 at 10:18, Björn Töpel <bjorn.topel@gmail.com> wrote:
>>
>> From: Björn Töpel <bjorn.topel@intel.com>
>>
>> Brendan Jackman added extend atomic operations to the BPF instruction
>> set in commit 7064a7341a0d ("Merge branch 'Atomics for eBPF'"), which
>> introduces the BPF_ATOMIC_OP macro. However, that macro was missing
>> for the BPF samples. Fix that by adding it into bpf_insn.h.
>>
>> Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
> 
> Reviewed-by: Brendan Jackman <jackmanb@google.com>
>

Thanks!
Björn
patchwork-bot+netdevbpf@kernel.org Jan. 18, 2021, 11 p.m. UTC | #3 
Hello:

This patch was applied to bpf/bpf-next.git (refs/heads/master):

On Mon, 18 Jan 2021 10:17:53 +0100 you wrote:
> From: Björn Töpel <bjorn.topel@intel.com>
> 
> Brendan Jackman added extend atomic operations to the BPF instruction
> set in commit 7064a7341a0d ("Merge branch 'Atomics for eBPF'"), which
> introduces the BPF_ATOMIC_OP macro. However, that macro was missing
> for the BPF samples. Fix that by adding it into bpf_insn.h.
> 
> [...]

Here is the summary with links:
  - [bpf-next] samples/bpf: add BPF_ATOMIC_OP macro for BPF samples
    https://git.kernel.org/bpf/bpf-next/c/af6953b633b3

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
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diff mbox series

Patch

diff --git a/samples/bpf/bpf_insn.h b/samples/bpf/bpf_insn.h
index db67a2847395..aee04534483a 100644
--- a/samples/bpf/bpf_insn.h
+++ b/samples/bpf/bpf_insn.h
@@ -134,15 +134,31 @@  struct bpf_insn;
 		.off   = OFF,					\
 		.imm   = 0 })
 
-/* Atomic memory add, *(uint *)(dst_reg + off16) += src_reg */
-
-#define BPF_STX_XADD(SIZE, DST, SRC, OFF)			\
+/*
+ * Atomic operations:
+ *
+ *   BPF_ADD                  *(uint *) (dst_reg + off16) += src_reg
+ *   BPF_AND                  *(uint *) (dst_reg + off16) &= src_reg
+ *   BPF_OR                   *(uint *) (dst_reg + off16) |= src_reg
+ *   BPF_XOR                  *(uint *) (dst_reg + off16) ^= src_reg
+ *   BPF_ADD | BPF_FETCH      src_reg = atomic_fetch_add(dst_reg + off16, src_reg);
+ *   BPF_AND | BPF_FETCH      src_reg = atomic_fetch_and(dst_reg + off16, src_reg);
+ *   BPF_OR | BPF_FETCH       src_reg = atomic_fetch_or(dst_reg + off16, src_reg);
+ *   BPF_XOR | BPF_FETCH      src_reg = atomic_fetch_xor(dst_reg + off16, src_reg);
+ *   BPF_XCHG                 src_reg = atomic_xchg(dst_reg + off16, src_reg)
+ *   BPF_CMPXCHG              r0 = atomic_cmpxchg(dst_reg + off16, r0, src_reg)
+ */
+
+#define BPF_ATOMIC_OP(SIZE, OP, DST, SRC, OFF)			\
 	((struct bpf_insn) {					\
 		.code  = BPF_STX | BPF_SIZE(SIZE) | BPF_ATOMIC,	\
 		.dst_reg = DST,					\
 		.src_reg = SRC,					\
 		.off   = OFF,					\
-		.imm   = BPF_ADD })
+		.imm   = OP })
+
+/* Legacy alias */
+#define BPF_STX_XADD(SIZE, DST, SRC, OFF) BPF_ATOMIC_OP(SIZE, BPF_ADD, DST, SRC, OFF)
 
 /* Memory store, *(uint *) (dst_reg + off16) = imm32 */