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nfp: bpf: implement memory bulk copy for length bigger than 32-bytes

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When the gathered copy length is bigger than 32-bytes and within 128-bytes
(the maximum length a single CPP Pull/Push request can finish), the
strategy of read/write are changeed into:

  * Read.
      - use direct reference mode when length is within 32-bytes.
      - use indirect mode when length is bigger than 32-bytes.

  * Write.
      - length <= 8-bytes
        use write8 (direct_ref).
      - length <= 32-byte and 4-bytes aligned
        use write32 (direct_ref).
      - length <= 32-bytes but not 4-bytes aligned
        use write8 (indirect_ref).
      - length > 32-bytes and 4-bytes aligned
        use write32 (indirect_ref).
      - length > 32-bytes and not 4-bytes aligned and <= 40-bytes
        use write32 (direct_ref) to finish the first 32-bytes.
        use write8 (direct_ref) to finish all remaining hanging part.
      - length > 32-bytes and not 4-bytes aligned
        use write32 (indirect_ref) to finish those 4-byte aligned parts.
        use write8 (direct_ref) to finish all remaining hanging part.

Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Jiong Wang 2017-11-30 21:32:59 -08:00 committed by Daniel Borkmann
parent 9879a3814b
commit 8c90053858
1 changed files with 45 additions and 7 deletions
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52
drivers/net/ethernet/netronome/nfp/bpf/jit.c
View File

@ -544,16 +544,18 @@ static int nfp_cpp_memcpy(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
unsigned int i;
u8 xfer_num;
if (WARN_ON_ONCE(len > 32))
return -EOPNOTSUPP;
off = re_load_imm_any(nfp_prog, meta->insn.off, imm_b(nfp_prog));
src_base = reg_a(meta->insn.src_reg * 2);
xfer_num = round_up(len, 4) / 4;
/* Setup PREV_ALU fields to override memory read length. */
if (len > 32)
wrp_immed(nfp_prog, reg_none(),
CMD_OVE_LEN | FIELD_PREP(CMD_OV_LEN, xfer_num - 1));
/* Memory read from source addr into transfer-in registers. */
emit_cmd(nfp_prog, CMD_TGT_READ32_SWAP, CMD_MODE_32b, 0, src_base, off,
xfer_num - 1, true);
emit_cmd_any(nfp_prog, CMD_TGT_READ32_SWAP, CMD_MODE_32b, 0, src_base,
off, xfer_num - 1, true, len > 32);
/* Move from transfer-in to transfer-out. */
for (i = 0; i < xfer_num; i++)
@ -566,18 +568,54 @@ static int nfp_cpp_memcpy(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
emit_cmd(nfp_prog, CMD_TGT_WRITE8_SWAP, CMD_MODE_32b, 0,
reg_a(meta->paired_st->dst_reg * 2), off, len - 1,
true);
} else if (IS_ALIGNED(len, 4)) {
} else if (len <= 32 && IS_ALIGNED(len, 4)) {
/* Use single direct_ref write32. */
emit_cmd(nfp_prog, CMD_TGT_WRITE32_SWAP, CMD_MODE_32b, 0,
reg_a(meta->paired_st->dst_reg * 2), off, xfer_num - 1,
true);
} else {
} else if (len <= 32) {
/* Use single indirect_ref write8. */
wrp_immed(nfp_prog, reg_none(),
CMD_OVE_LEN | FIELD_PREP(CMD_OV_LEN, len - 1));
emit_cmd_indir(nfp_prog, CMD_TGT_WRITE8_SWAP, CMD_MODE_32b, 0,
reg_a(meta->paired_st->dst_reg * 2), off,
len - 1, true);
} else if (IS_ALIGNED(len, 4)) {
/* Use single indirect_ref write32. */
wrp_immed(nfp_prog, reg_none(),
CMD_OVE_LEN | FIELD_PREP(CMD_OV_LEN, xfer_num - 1));
emit_cmd_indir(nfp_prog, CMD_TGT_WRITE32_SWAP, CMD_MODE_32b, 0,
reg_a(meta->paired_st->dst_reg * 2), off,
xfer_num - 1, true);
} else if (len <= 40) {
/* Use one direct_ref write32 to write the first 32-bytes, then
* another direct_ref write8 to write the remaining bytes.
*/
emit_cmd(nfp_prog, CMD_TGT_WRITE32_SWAP, CMD_MODE_32b, 0,
reg_a(meta->paired_st->dst_reg * 2), off, 7,
true);
off = re_load_imm_any(nfp_prog, meta->paired_st->off + 32,
imm_b(nfp_prog));
emit_cmd(nfp_prog, CMD_TGT_WRITE8_SWAP, CMD_MODE_32b, 8,
reg_a(meta->paired_st->dst_reg * 2), off, len - 33,
true);
} else {
/* Use one indirect_ref write32 to write 4-bytes aligned length,
* then another direct_ref write8 to write the remaining bytes.
*/
u8 new_off;
wrp_immed(nfp_prog, reg_none(),
CMD_OVE_LEN | FIELD_PREP(CMD_OV_LEN, xfer_num - 2));
emit_cmd_indir(nfp_prog, CMD_TGT_WRITE32_SWAP, CMD_MODE_32b, 0,
reg_a(meta->paired_st->dst_reg * 2), off,
xfer_num - 2, true);
new_off = meta->paired_st->off + (xfer_num - 1) * 4;
off = re_load_imm_any(nfp_prog, new_off, imm_b(nfp_prog));
emit_cmd(nfp_prog, CMD_TGT_WRITE8_SWAP, CMD_MODE_32b,
xfer_num - 1, reg_a(meta->paired_st->dst_reg * 2), off,
(len & 0x3) - 1, true);
}
/* TODO: The following extra load is to make sure data flow be identical