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.
Acked-by: Yonghong Song <y...@fb.com>
Signed-off-by: Brendan Jackman <jackm...@google.com>
---
kernel/bpf/core.c | 80 +++++++++++++++++++++++------------------------
1 file changed, 39 insertions(+), 41 deletions(-)
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 28f960bc2e30..1d9e5dcde03a 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -1618,55 +1618,53 @@ 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_ALU_OP(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_ALU_OP(BPF_ADD, add)
+#undef ATOMIC_ALU_OP
+
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;
}
--
2.29.2.576.ga3fc446d84-goog
