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* [PATCH bpf-next] Enable zext optimization for more RV64G ALU ops
@ 2019-07-05  0:18 Luke Nelson
  2019-07-05  6:31 ` Björn Töpel
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Luke Nelson @ 2019-07-05  0:18 UTC (permalink / raw)
  To: linux-kernel
  Cc: Song Liu, Albert Ou, bpf, Daniel Borkmann, Luke Nelson,
	Jiong Wang, Björn Töpel, Palmer Dabbelt, Song Liu,
	Alexei Starovoitov, netdev, Yonghong Song, linux-riscv,
	Martin KaFai Lau, Xi Wang

commit 66d0d5a854a6 ("riscv: bpf: eliminate zero extension code-gen")
added the new zero-extension optimization for some BPF ALU operations.

Since then, bugs in the JIT that have been fixed in the bpf tree require
this optimization to be added to other operations: commit 1e692f09e091
("bpf, riscv: clear high 32 bits for ALU32 add/sub/neg/lsh/rsh/arsh"),
and commit fe121ee531d1 ("bpf, riscv: clear target register high 32-bits
for and/or/xor on ALU32")

Now that these have been merged to bpf-next, the zext optimization can
be enabled for the fixed operations.

Cc: Song Liu <liu.song.a23@gmail.com>
Cc: Jiong Wang <jiong.wang@netronome.com>
Cc: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Luke Nelson <luke.r.nels@gmail.com>
---
 arch/riscv/net/bpf_jit_comp.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/riscv/net/bpf_jit_comp.c b/arch/riscv/net/bpf_jit_comp.c
index 876cb9c705ce..5451ef3845f2 100644
--- a/arch/riscv/net/bpf_jit_comp.c
+++ b/arch/riscv/net/bpf_jit_comp.c
@@ -757,31 +757,31 @@ static int emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 	case BPF_ALU | BPF_ADD | BPF_X:
 	case BPF_ALU64 | BPF_ADD | BPF_X:
 		emit(is64 ? rv_add(rd, rd, rs) : rv_addw(rd, rd, rs), ctx);
-		if (!is64)
+		if (!is64 && !aux->verifier_zext)
 			emit_zext_32(rd, ctx);
 		break;
 	case BPF_ALU | BPF_SUB | BPF_X:
 	case BPF_ALU64 | BPF_SUB | BPF_X:
 		emit(is64 ? rv_sub(rd, rd, rs) : rv_subw(rd, rd, rs), ctx);
-		if (!is64)
+		if (!is64 && !aux->verifier_zext)
 			emit_zext_32(rd, ctx);
 		break;
 	case BPF_ALU | BPF_AND | BPF_X:
 	case BPF_ALU64 | BPF_AND | BPF_X:
 		emit(rv_and(rd, rd, rs), ctx);
-		if (!is64)
+		if (!is64 && !aux->verifier_zext)
 			emit_zext_32(rd, ctx);
 		break;
 	case BPF_ALU | BPF_OR | BPF_X:
 	case BPF_ALU64 | BPF_OR | BPF_X:
 		emit(rv_or(rd, rd, rs), ctx);
-		if (!is64)
+		if (!is64 && !aux->verifier_zext)
 			emit_zext_32(rd, ctx);
 		break;
 	case BPF_ALU | BPF_XOR | BPF_X:
 	case BPF_ALU64 | BPF_XOR | BPF_X:
 		emit(rv_xor(rd, rd, rs), ctx);
-		if (!is64)
+		if (!is64 && !aux->verifier_zext)
 			emit_zext_32(rd, ctx);
 		break;
 	case BPF_ALU | BPF_MUL | BPF_X:
@@ -811,13 +811,13 @@ static int emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 	case BPF_ALU | BPF_RSH | BPF_X:
 	case BPF_ALU64 | BPF_RSH | BPF_X:
 		emit(is64 ? rv_srl(rd, rd, rs) : rv_srlw(rd, rd, rs), ctx);
-		if (!is64)
+		if (!is64 && !aux->verifier_zext)
 			emit_zext_32(rd, ctx);
 		break;
 	case BPF_ALU | BPF_ARSH | BPF_X:
 	case BPF_ALU64 | BPF_ARSH | BPF_X:
 		emit(is64 ? rv_sra(rd, rd, rs) : rv_sraw(rd, rd, rs), ctx);
-		if (!is64)
+		if (!is64 && !aux->verifier_zext)
 			emit_zext_32(rd, ctx);
 		break;
 
@@ -826,7 +826,7 @@ static int emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 	case BPF_ALU64 | BPF_NEG:
 		emit(is64 ? rv_sub(rd, RV_REG_ZERO, rd) :
 		     rv_subw(rd, RV_REG_ZERO, rd), ctx);
-		if (!is64)
+		if (!is64 && !aux->verifier_zext)
 			emit_zext_32(rd, ctx);
 		break;
 
-- 
2.20.1


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Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-07-05  0:18 [PATCH bpf-next] Enable zext optimization for more RV64G ALU ops Luke Nelson
2019-07-05  6:31 ` Björn Töpel
2019-07-05  9:24 ` Jiong Wang
2019-07-05 22:01 ` Daniel Borkmann

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