From: Brendan Jackman <jackmanb@google.com>
To: bpf@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>, Yonghong Song <yhs@fb.com>,
Daniel Borkmann <daniel@iogearbox.net>,
KP Singh <kpsingh@chromium.org>,
Florent Revest <revest@chromium.org>,
linux-kernel@vger.kernel.org, Jann Horn <jannh@google.com>,
Brendan Jackman <jackmanb@google.com>
Subject: [PATCH v2 bpf-next 09/13] bpf: Pull out a macro for interpreting atomic ALU operations
Date: Fri, 27 Nov 2020 17:57:34 +0000 [thread overview]
Message-ID: <20201127175738.1085417-10-jackmanb@google.com> (raw)
In-Reply-To: <20201127175738.1085417-1-jackmanb@google.com>
Since the atomic operations that are added in subsequent commits are
all isomorphic with BPF_ADD, pull out a macro to avoid the
interpreter becoming dominated by lines of atomic-related code.
Note that this sacrificies interpreter performance (combining
STX_ATOMIC_W and STX_ATOMIC_DW into single switch case means that we
need an extra conditional branch to differentiate them) in favour of
compact and (relatively!) simple C code.
Signed-off-by: Brendan Jackman <jackmanb@google.com>
---
kernel/bpf/core.c | 79 +++++++++++++++++++++++------------------------
1 file changed, 38 insertions(+), 41 deletions(-)
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 05350a8f87c0..20a5351d1dc2 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -1626,55 +1626,52 @@ static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack)
LDX_PROBE(DW, 8)
#undef LDX_PROBE
- STX_ATOMIC_W:
- switch (IMM) {
- case BPF_ADD:
- /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
- atomic_add((u32) SRC, (atomic_t *)(unsigned long)
- (DST + insn->off));
- break;
- case BPF_ADD | BPF_FETCH:
- SRC = (u32) atomic_fetch_add(
- (u32) SRC,
- (atomic_t *)(unsigned long) (DST + insn->off));
- break;
- case BPF_XCHG:
- SRC = (u32) atomic_xchg(
- (atomic_t *)(unsigned long) (DST + insn->off),
- (u32) SRC);
- break;
- case BPF_CMPXCHG:
- BPF_R0 = (u32) atomic_cmpxchg(
- (atomic_t *)(unsigned long) (DST + insn->off),
- (u32) BPF_R0, (u32) SRC);
+#define ATOMIC(BOP, KOP) \
+ case BOP: \
+ if (BPF_SIZE(insn->code) == BPF_W) \
+ atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \
+ (DST + insn->off)); \
+ else \
+ atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \
+ (DST + insn->off)); \
+ break; \
+ case BOP | BPF_FETCH: \
+ if (BPF_SIZE(insn->code) == BPF_W) \
+ SRC = (u32) atomic_fetch_##KOP( \
+ (u32) SRC, \
+ (atomic_t *)(unsigned long) (DST + insn->off)); \
+ else \
+ SRC = (u64) atomic64_fetch_##KOP( \
+ (u64) SRC, \
+ (atomic64_t *)(s64) (DST + insn->off)); \
break;
- default:
- goto default_label;
- }
- CONT;
STX_ATOMIC_DW:
+ STX_ATOMIC_W:
switch (IMM) {
- case BPF_ADD:
- /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
- atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
- (DST + insn->off));
- break;
- case BPF_ADD | BPF_FETCH:
- SRC = (u64) atomic64_fetch_add(
- (u64) SRC,
- (atomic64_t *)(s64) (DST + insn->off));
- break;
+ ATOMIC(BPF_ADD, add)
+
case BPF_XCHG:
- SRC = (u64) atomic64_xchg(
- (atomic64_t *)(u64) (DST + insn->off),
- (u64) SRC);
+ if (BPF_SIZE(insn->code) == BPF_W)
+ SRC = (u32) atomic_xchg(
+ (atomic_t *)(unsigned long) (DST + insn->off),
+ (u32) SRC);
+ else
+ SRC = (u64) atomic64_xchg(
+ (atomic64_t *)(u64) (DST + insn->off),
+ (u64) SRC);
break;
case BPF_CMPXCHG:
- BPF_R0 = (u64) atomic64_cmpxchg(
- (atomic64_t *)(u64) (DST + insn->off),
- (u64) BPF_R0, (u64) SRC);
+ if (BPF_SIZE(insn->code) == BPF_W)
+ BPF_R0 = (u32) atomic_cmpxchg(
+ (atomic_t *)(unsigned long) (DST + insn->off),
+ (u32) BPF_R0, (u32) SRC);
+ else
+ BPF_R0 = (u64) atomic64_cmpxchg(
+ (atomic64_t *)(u64) (DST + insn->off),
+ (u64) BPF_R0, (u64) SRC);
break;
+
default:
goto default_label;
}
--
2.29.2.454.gaff20da3a2-goog
next prev parent reply other threads:[~2020-11-27 17:58 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-27 17:57 [PATCH v2 bpf-next 00/13] Atomics for eBPF Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 01/13] bpf: x86: Factor out emission of ModR/M for *(reg + off) Brendan Jackman
2020-11-29 1:15 ` Alexei Starovoitov
2020-12-01 12:14 ` Brendan Jackman
2020-12-02 5:50 ` Alexei Starovoitov
2020-12-02 10:52 ` Brendan Jackman
2020-12-02 17:35 ` Alexei Starovoitov
2020-11-27 17:57 ` [PATCH v2 bpf-next 02/13] bpf: x86: Factor out emission of REX byte Brendan Jackman
2020-11-29 1:14 ` Alexei Starovoitov
2020-12-01 12:12 ` Brendan Jackman
2020-12-02 5:48 ` Alexei Starovoitov
2020-12-02 10:54 ` Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 03/13] bpf: x86: Factor out function to emit NEG Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 04/13] bpf: x86: Factor out a lookup table for some ALU opcodes Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 05/13] bpf: Rename BPF_XADD and prepare to encode other atomics in .imm Brendan Jackman
2020-11-28 3:43 ` Yonghong Song
2020-12-01 12:17 ` Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 06/13] bpf: Move BPF_STX reserved field check into BPF_STX verifier code Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 07/13] bpf: Add BPF_FETCH field / create atomic_fetch_add instruction Brendan Jackman
2020-11-28 4:15 ` Yonghong Song
2020-12-01 12:22 ` Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 08/13] bpf: Add instructions for atomic_[cmp]xchg Brendan Jackman
2020-11-28 5:25 ` Yonghong Song
2020-12-01 12:27 ` Brendan Jackman
2020-11-29 1:27 ` Alexei Starovoitov
2020-12-01 12:32 ` Brendan Jackman
2020-11-27 17:57 ` Brendan Jackman [this message]
2020-11-27 17:57 ` [PATCH v2 bpf-next 10/13] bpf: Add instructions for atomic[64]_[fetch_]sub Brendan Jackman
2020-11-27 21:39 ` kernel test robot
2020-11-27 21:39 ` [RFC PATCH] bpf: bpf_atomic_alu_string[] can be static kernel test robot
2020-11-28 5:35 ` [PATCH v2 bpf-next 10/13] bpf: Add instructions for atomic[64]_[fetch_]sub Yonghong Song
2020-11-29 1:34 ` Alexei Starovoitov
2020-11-30 17:18 ` Yonghong Song
2020-12-01 12:38 ` Brendan Jackman
2020-12-02 5:55 ` Alexei Starovoitov
2020-12-02 11:19 ` Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 11/13] bpf: Add bitwise atomic instructions Brendan Jackman
2020-11-28 5:39 ` Yonghong Song
2020-11-29 1:36 ` Alexei Starovoitov
2020-11-30 17:20 ` Yonghong Song
2020-11-27 17:57 ` [PATCH v2 bpf-next 12/13] bpf: Add tests for new BPF atomic operations Brendan Jackman
2020-12-01 3:55 ` Yonghong Song
2020-12-01 12:56 ` Brendan Jackman
2020-12-01 17:24 ` Yonghong Song
2020-12-02 2:22 ` Andrii Nakryiko
2020-12-02 12:26 ` Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 13/13] bpf: Document new atomic instructions Brendan Jackman
2020-11-28 5:53 ` [PATCH v2 bpf-next 00/13] Atomics for eBPF Yonghong Song
2020-11-29 1:40 ` Alexei Starovoitov
2020-11-30 17:22 ` Yonghong Song
2020-12-01 3:48 ` Yonghong Song
2020-12-02 2:00 ` Andrii Nakryiko
2020-12-02 5:05 ` Yonghong Song
2020-12-02 5:53 ` John Fastabend
2020-12-02 5:59 ` Andrii Nakryiko
2020-12-02 6:27 ` John Fastabend
2020-12-02 8:03 ` Yonghong Song
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