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MIPS: BPF: Free up some callee-saved registers
Move the two scratch registers from s0 and s1 to t4 and t5 in order to free up some callee-saved registers. We will use these callee-saved registers to store some permanent data on them in a subsequent patch. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Cc: netdev@vger.kernel.org Cc: "David S. Miller" <davem@davemloft.net> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Daniel Borkmann <dborkman@redhat.com> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/10525/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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de5792a4ec
commit
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2 changed files with 17 additions and 20 deletions
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@ -29,9 +29,6 @@
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/* ABI
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*
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* s0 1st scratch register
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* s1 2nd scratch register
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* s2 offset register
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* s3 BPF register A
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* s4 BPF register X
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* s5 *skb
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@ -88,13 +85,13 @@
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* any of the $s0-$s6 registers will only be preserved if
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* they are going to actually be used.
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*/
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#define r_s0 MIPS_R_S0 /* scratch reg 1 */
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#define r_s1 MIPS_R_S1 /* scratch reg 2 */
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#define r_off MIPS_R_S2
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#define r_A MIPS_R_S3
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#define r_X MIPS_R_S4
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#define r_skb MIPS_R_S5
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#define r_M MIPS_R_S6
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#define r_s0 MIPS_R_T4 /* scratch reg 1 */
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#define r_s1 MIPS_R_T5 /* scratch reg 2 */
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#define r_tmp_imm MIPS_R_T6 /* No need to preserve this */
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#define r_tmp MIPS_R_T7 /* No need to preserve this */
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#define r_zero MIPS_R_ZERO
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@ -108,8 +105,6 @@
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#define SEEN_SREG_SFT (BPF_MEMWORDS + 1)
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#define SEEN_SREG_BASE (1 << SEEN_SREG_SFT)
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#define SEEN_SREG(x) (SEEN_SREG_BASE << (x))
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#define SEEN_S0 SEEN_SREG(0)
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#define SEEN_S1 SEEN_SREG(1)
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#define SEEN_OFF SEEN_SREG(2)
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#define SEEN_A SEEN_SREG(3)
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#define SEEN_X SEEN_SREG(4)
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@ -813,7 +808,7 @@ static int build_body(struct jit_ctx *ctx)
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b_imm(prog->len, ctx), ctx);
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emit_reg_move(r_ret, r_zero, ctx);
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ctx->flags |= SEEN_CALL | SEEN_OFF | SEEN_S0 |
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ctx->flags |= SEEN_CALL | SEEN_OFF |
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SEEN_SKB | SEEN_A;
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emit_load_func(r_s0, (ptr)load_func[load_order],
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@ -879,7 +874,7 @@ static int build_body(struct jit_ctx *ctx)
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return -ENOTSUPP;
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/* X <- 4 * (P[k:1] & 0xf) */
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ctx->flags |= SEEN_X | SEEN_CALL | SEEN_S0 | SEEN_SKB;
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ctx->flags |= SEEN_X | SEEN_CALL | SEEN_SKB;
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/* Load offset to a1 */
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emit_load_func(r_s0, (ptr)jit_get_skb_b, ctx);
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/*
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@ -943,7 +938,7 @@ static int build_body(struct jit_ctx *ctx)
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case BPF_ALU | BPF_MUL | BPF_K:
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/* A *= K */
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/* Load K to scratch register before MUL */
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ctx->flags |= SEEN_A | SEEN_S0;
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ctx->flags |= SEEN_A;
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emit_load_imm(r_s0, k, ctx);
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emit_mul(r_A, r_A, r_s0, ctx);
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break;
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@ -961,7 +956,7 @@ static int build_body(struct jit_ctx *ctx)
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emit_srl(r_A, r_A, k, ctx);
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break;
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}
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ctx->flags |= SEEN_A | SEEN_S0;
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ctx->flags |= SEEN_A;
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emit_load_imm(r_s0, k, ctx);
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emit_div(r_A, r_s0, ctx);
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break;
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@ -971,7 +966,7 @@ static int build_body(struct jit_ctx *ctx)
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ctx->flags |= SEEN_A;
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emit_jit_reg_move(r_A, r_zero, ctx);
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} else {
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ctx->flags |= SEEN_A | SEEN_S0;
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ctx->flags |= SEEN_A;
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emit_load_imm(r_s0, k, ctx);
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emit_mod(r_A, r_s0, ctx);
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}
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@ -1085,10 +1080,10 @@ static int build_body(struct jit_ctx *ctx)
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if ((condt & MIPS_COND_GE) ||
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(condt & MIPS_COND_GT)) {
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if (condt & MIPS_COND_K) { /* K */
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ctx->flags |= SEEN_S0 | SEEN_A;
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ctx->flags |= SEEN_A;
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emit_sltiu(r_s0, r_A, k, ctx);
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} else { /* X */
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ctx->flags |= SEEN_S0 | SEEN_A |
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ctx->flags |= SEEN_A |
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SEEN_X;
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emit_sltu(r_s0, r_A, r_X, ctx);
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}
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@ -1100,7 +1095,7 @@ static int build_body(struct jit_ctx *ctx)
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/* A > (K|X) ? scratch = 0 */
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if (condt & MIPS_COND_GT) {
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/* Checking for equality */
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ctx->flags |= SEEN_S0 | SEEN_A | SEEN_X;
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ctx->flags |= SEEN_A | SEEN_X;
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if (condt & MIPS_COND_K)
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emit_load_imm(r_s0, k, ctx);
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else
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@ -1123,7 +1118,7 @@ static int build_body(struct jit_ctx *ctx)
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} else {
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/* A == K|X */
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if (condt & MIPS_COND_K) { /* K */
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ctx->flags |= SEEN_S0 | SEEN_A;
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ctx->flags |= SEEN_A;
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emit_load_imm(r_s0, k, ctx);
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/* jump true */
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b_off = b_imm(i + inst->jt + 1, ctx);
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@ -1153,7 +1148,7 @@ static int build_body(struct jit_ctx *ctx)
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}
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break;
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case BPF_JMP | BPF_JSET | BPF_K:
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ctx->flags |= SEEN_S0 | SEEN_S1 | SEEN_A;
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ctx->flags |= SEEN_A;
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/* pc += (A & K) ? pc -> jt : pc -> jf */
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emit_load_imm(r_s1, k, ctx);
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emit_and(r_s0, r_A, r_s1, ctx);
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@ -1167,7 +1162,7 @@ static int build_body(struct jit_ctx *ctx)
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emit_nop(ctx);
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break;
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case BPF_JMP | BPF_JSET | BPF_X:
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ctx->flags |= SEEN_S0 | SEEN_X | SEEN_A;
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ctx->flags |= SEEN_X | SEEN_A;
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/* pc += (A & X) ? pc -> jt : pc -> jf */
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emit_and(r_s0, r_A, r_X, ctx);
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/* jump true */
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@ -1251,7 +1246,7 @@ static int build_body(struct jit_ctx *ctx)
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break;
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case BPF_ANC | SKF_AD_IFINDEX:
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/* A = skb->dev->ifindex */
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ctx->flags |= SEEN_SKB | SEEN_A | SEEN_S0;
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ctx->flags |= SEEN_SKB | SEEN_A;
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off = offsetof(struct sk_buff, dev);
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/* Load *dev pointer */
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emit_load_ptr(r_s0, r_skb, off, ctx);
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@ -1278,7 +1273,7 @@ static int build_body(struct jit_ctx *ctx)
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break;
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case BPF_ANC | SKF_AD_VLAN_TAG:
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case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT:
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ctx->flags |= SEEN_SKB | SEEN_S0 | SEEN_A;
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ctx->flags |= SEEN_SKB | SEEN_A;
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BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
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vlan_tci) != 2);
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off = offsetof(struct sk_buff, vlan_tci);
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@ -18,6 +18,8 @@
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#define MIPS_R_V1 3
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#define MIPS_R_A0 4
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#define MIPS_R_A1 5
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#define MIPS_R_T4 12
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#define MIPS_R_T5 13
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#define MIPS_R_T6 14
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#define MIPS_R_T7 15
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#define MIPS_R_S0 16
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