netdev - [PATCH v5 bpf-next 14/17] sparc: bpf: eliminate zero extension code-gen

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Date:   Wed,  1 May 2019 15:43:59 +0100
From:   Jiong Wang <jiong.wang@...ronome.com>
To:     alexei.starovoitov@...il.com, daniel@...earbox.net
Cc:     bpf@...r.kernel.org, netdev@...r.kernel.org,
        oss-drivers@...ronome.com, Jiong Wang <jiong.wang@...ronome.com>,
        "David S . Miller" <davem@...emloft.net>
Subject: [PATCH v5 bpf-next 14/17] sparc: bpf: eliminate zero extension code-gen

Cc: David S. Miller <davem@...emloft.net>
Signed-off-by: Jiong Wang <jiong.wang@...ronome.com>
---
 arch/sparc/net/bpf_jit_comp_64.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/sparc/net/bpf_jit_comp_64.c b/arch/sparc/net/bpf_jit_comp_64.c
index 65428e7..8318d3a 100644
--- a/arch/sparc/net/bpf_jit_comp_64.c
+++ b/arch/sparc/net/bpf_jit_comp_64.c
@@ -905,6 +905,10 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 		ctx->saw_frame_pointer = true;
 
 	switch (code) {
+	/* explicit zero extension */
+	case BPF_ALU | BPF_ZEXT:
+		emit_alu_K(SRL, dst, 0, ctx);
+		break;
 	/* dst = src */
 	case BPF_ALU | BPF_MOV | BPF_X:
 		emit_alu3_K(SRL, src, 0, dst, ctx);
@@ -1144,7 +1148,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 		break;
 
 	do_alu32_trunc:
-		if (BPF_CLASS(code) == BPF_ALU)
+		if (BPF_CLASS(code) == BPF_ALU &&
+		    !ctx->prog->aux->verifier_zext)
 			emit_alu_K(SRL, dst, 0, ctx);
 		break;
 
@@ -1432,6 +1437,11 @@ static void jit_fill_hole(void *area, unsigned int size)
 		*ptr++ = 0x91d02005; /* ta 5 */
 }
 
+bool bpf_jit_hardware_zext(void)
+{
+	return false;
+}
+
 struct sparc64_jit_data {
 	struct bpf_binary_header *header;
 	u8 *image;
-- 
2.7.4