Skip to content

Commit

Permalink
MIPS,bpf: Cache value of BPF_OP(insn->code) in eBPF JIT.
Browse files Browse the repository at this point in the history 
The code looks a little cleaner if we replace BPF_OP(insn->code) with
the local variable bpf_op.  Caching the value this way also saves 300
bytes (about 1%) in the code size of the JIT.

Signed-off-by: David Daney <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
  • Loading branch information
@daviddaney @davem330
daviddaney authored and davem330 committed Aug 21, 2017
1 parent a67b375 commit 6035b3f
Showing 1 changed file with 34 additions and 33 deletions.
67 changes: 34 additions & 33 deletions arch/mips/net/ebpf_jit.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -670,6 +670,7 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
unsigned int target;
u64 t64;
s64 t64s;
int bpf_op = BPF_OP(insn->code);

switch (insn->code) {
case BPF_ALU64 | BPF_ADD | BPF_K: /* ALU64_IMM */
Expand Down Expand Up @@ -758,13 +759,13 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
emit_instr(ctx, sll, dst, dst, 0);
if (insn->imm == 1) {
/* div by 1 is a nop, mod by 1 is zero */
if (BPF_OP(insn->code) == BPF_MOD)
if (bpf_op == BPF_MOD)
emit_instr(ctx, addu, dst, MIPS_R_ZERO, MIPS_R_ZERO);
break;
}
gen_imm_to_reg(insn, MIPS_R_AT, ctx);
emit_instr(ctx, divu, dst, MIPS_R_AT);
if (BPF_OP(insn->code) == BPF_DIV)
if (bpf_op == BPF_DIV)
emit_instr(ctx, mflo, dst);
else
emit_instr(ctx, mfhi, dst);
Expand All @@ -786,13 +787,13 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,

if (insn->imm == 1) {
/* div by 1 is a nop, mod by 1 is zero */
if (BPF_OP(insn->code) == BPF_MOD)
if (bpf_op == BPF_MOD)
emit_instr(ctx, addu, dst, MIPS_R_ZERO, MIPS_R_ZERO);
break;
}
gen_imm_to_reg(insn, MIPS_R_AT, ctx);
emit_instr(ctx, ddivu, dst, MIPS_R_AT);
if (BPF_OP(insn->code) == BPF_DIV)
if (bpf_op == BPF_DIV)
emit_instr(ctx, mflo, dst);
else
emit_instr(ctx, mfhi, dst);
Expand All @@ -817,7 +818,7 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
emit_instr(ctx, dinsu, dst, MIPS_R_ZERO, 32, 32);
did_move = false;
if (insn->src_reg == BPF_REG_10) {
if (BPF_OP(insn->code) == BPF_MOV) {
if (bpf_op == BPF_MOV) {
emit_instr(ctx, daddiu, dst, MIPS_R_SP, MAX_BPF_STACK);
did_move = true;
} else {
Expand All @@ -827,15 +828,15 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
} else if (get_reg_val_type(ctx, this_idx, insn->src_reg) == REG_32BIT) {
int tmp_reg = MIPS_R_AT;

if (BPF_OP(insn->code) == BPF_MOV) {
if (bpf_op == BPF_MOV) {
tmp_reg = dst;
did_move = true;
}
emit_instr(ctx, daddu, tmp_reg, src, MIPS_R_ZERO);
emit_instr(ctx, dinsu, tmp_reg, MIPS_R_ZERO, 32, 32);
src = MIPS_R_AT;
}
switch (BPF_OP(insn->code)) {
switch (bpf_op) {
case BPF_MOV:
if (!did_move)
emit_instr(ctx, daddu, dst, src, MIPS_R_ZERO);
Expand Down Expand Up @@ -867,7 +868,7 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
emit_instr(ctx, beq, src, MIPS_R_ZERO, b_off);
emit_instr(ctx, movz, MIPS_R_V0, MIPS_R_ZERO, src);
emit_instr(ctx, ddivu, dst, src);
if (BPF_OP(insn->code) == BPF_DIV)
if (bpf_op == BPF_DIV)
emit_instr(ctx, mflo, dst);
else
emit_instr(ctx, mfhi, dst);
Expand Down Expand Up @@ -911,15 +912,15 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
if (ts == REG_64BIT || ts == REG_32BIT_ZERO_EX) {
int tmp_reg = MIPS_R_AT;

if (BPF_OP(insn->code) == BPF_MOV) {
if (bpf_op == BPF_MOV) {
tmp_reg = dst;
did_move = true;
}
/* sign extend */
emit_instr(ctx, sll, tmp_reg, src, 0);
src = MIPS_R_AT;
}
switch (BPF_OP(insn->code)) {
switch (bpf_op) {
case BPF_MOV:
if (!did_move)
emit_instr(ctx, addu, dst, src, MIPS_R_ZERO);
Expand Down Expand Up @@ -950,7 +951,7 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
emit_instr(ctx, beq, src, MIPS_R_ZERO, b_off);
emit_instr(ctx, movz, MIPS_R_V0, MIPS_R_ZERO, src);
emit_instr(ctx, divu, dst, src);
if (BPF_OP(insn->code) == BPF_DIV)
if (bpf_op == BPF_DIV)
emit_instr(ctx, mflo, dst);
else
emit_instr(ctx, mfhi, dst);
Expand All @@ -977,7 +978,7 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
break;
case BPF_JMP | BPF_JEQ | BPF_K: /* JMP_IMM */
case BPF_JMP | BPF_JNE | BPF_K: /* JMP_IMM */
cmp_eq = (BPF_OP(insn->code) == BPF_JEQ);
cmp_eq = (bpf_op == BPF_JEQ);
dst = ebpf_to_mips_reg(ctx, insn, dst_reg_fp_ok);
if (dst < 0)
return dst;
Expand Down Expand Up @@ -1012,18 +1013,18 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
emit_instr(ctx, sll, MIPS_R_AT, dst, 0);
dst = MIPS_R_AT;
}
if (BPF_OP(insn->code) == BPF_JSET) {
if (bpf_op == BPF_JSET) {
emit_instr(ctx, and, MIPS_R_AT, dst, src);
cmp_eq = false;
dst = MIPS_R_AT;
src = MIPS_R_ZERO;
} else if (BPF_OP(insn->code) == BPF_JSGT || BPF_OP(insn->code) == BPF_JSLE) {
} else if (bpf_op == BPF_JSGT || bpf_op == BPF_JSLE) {
emit_instr(ctx, dsubu, MIPS_R_AT, dst, src);
if ((insn + 1)->code == (BPF_JMP | BPF_EXIT) && insn->off == 1) {
b_off = b_imm(exit_idx, ctx);
if (is_bad_offset(b_off))
return -E2BIG;
if (BPF_OP(insn->code) == BPF_JSGT)
if (bpf_op == BPF_JSGT)
emit_instr(ctx, blez, MIPS_R_AT, b_off);
else
emit_instr(ctx, bgtz, MIPS_R_AT, b_off);
Expand All @@ -1033,35 +1034,35 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
b_off = b_imm(this_idx + insn->off + 1, ctx);
if (is_bad_offset(b_off))
return -E2BIG;
if (BPF_OP(insn->code) == BPF_JSGT)
if (bpf_op == BPF_JSGT)
emit_instr(ctx, bgtz, MIPS_R_AT, b_off);
else
emit_instr(ctx, blez, MIPS_R_AT, b_off);
emit_instr(ctx, nop);
break;
} else if (BPF_OP(insn->code) == BPF_JSGE || BPF_OP(insn->code) == BPF_JSLT) {
} else if (bpf_op == BPF_JSGE || bpf_op == BPF_JSLT) {
emit_instr(ctx, slt, MIPS_R_AT, dst, src);
cmp_eq = BPF_OP(insn->code) == BPF_JSGE;
cmp_eq = bpf_op == BPF_JSGE;
dst = MIPS_R_AT;
src = MIPS_R_ZERO;
} else if (BPF_OP(insn->code) == BPF_JGT || BPF_OP(insn->code) == BPF_JLE) {
} else if (bpf_op == BPF_JGT || bpf_op == BPF_JLE) {
/* dst or src could be AT */
emit_instr(ctx, dsubu, MIPS_R_T8, dst, src);
emit_instr(ctx, sltu, MIPS_R_AT, dst, src);
/* SP known to be non-zero, movz becomes boolean not */
emit_instr(ctx, movz, MIPS_R_T9, MIPS_R_SP, MIPS_R_T8);
emit_instr(ctx, movn, MIPS_R_T9, MIPS_R_ZERO, MIPS_R_T8);
emit_instr(ctx, or, MIPS_R_AT, MIPS_R_T9, MIPS_R_AT);
cmp_eq = BPF_OP(insn->code) == BPF_JGT;
cmp_eq = bpf_op == BPF_JGT;
dst = MIPS_R_AT;
src = MIPS_R_ZERO;
} else if (BPF_OP(insn->code) == BPF_JGE || BPF_OP(insn->code) == BPF_JLT) {
} else if (bpf_op == BPF_JGE || bpf_op == BPF_JLT) {
emit_instr(ctx, sltu, MIPS_R_AT, dst, src);
cmp_eq = BPF_OP(insn->code) == BPF_JGE;
cmp_eq = bpf_op == BPF_JGE;
dst = MIPS_R_AT;
src = MIPS_R_ZERO;
} else { /* JNE/JEQ case */
cmp_eq = (BPF_OP(insn->code) == BPF_JEQ);
cmp_eq = (bpf_op == BPF_JEQ);
}
jeq_common:
/*
Expand Down Expand Up @@ -1122,7 +1123,7 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
case BPF_JMP | BPF_JSGE | BPF_K: /* JMP_IMM */
case BPF_JMP | BPF_JSLT | BPF_K: /* JMP_IMM */
case BPF_JMP | BPF_JSLE | BPF_K: /* JMP_IMM */
cmp_eq = (BPF_OP(insn->code) == BPF_JSGE);
cmp_eq = (bpf_op == BPF_JSGE);
dst = ebpf_to_mips_reg(ctx, insn, dst_reg_fp_ok);
if (dst < 0)
return dst;
Expand All @@ -1132,7 +1133,7 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
b_off = b_imm(exit_idx, ctx);
if (is_bad_offset(b_off))
return -E2BIG;
switch (BPF_OP(insn->code)) {
switch (bpf_op) {
case BPF_JSGT:
emit_instr(ctx, blez, dst, b_off);
break;
Expand All @@ -1152,7 +1153,7 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
b_off = b_imm(this_idx + insn->off + 1, ctx);
if (is_bad_offset(b_off))
return -E2BIG;
switch (BPF_OP(insn->code)) {
switch (bpf_op) {
case BPF_JSGT:
emit_instr(ctx, bgtz, dst, b_off);
break;
Expand All @@ -1173,14 +1174,14 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
* only "LT" compare available, so we must use imm + 1
* to generate "GT" and imm -1 to generate LE
*/
if (BPF_OP(insn->code) == BPF_JSGT)
if (bpf_op == BPF_JSGT)
t64s = insn->imm + 1;
else if (BPF_OP(insn->code) == BPF_JSLE)
else if (bpf_op == BPF_JSLE)
t64s = insn->imm + 1;
else
t64s = insn->imm;

cmp_eq = BPF_OP(insn->code) == BPF_JSGT || BPF_OP(insn->code) == BPF_JSGE;
cmp_eq = bpf_op == BPF_JSGT || bpf_op == BPF_JSGE;
if (t64s >= S16_MIN && t64s <= S16_MAX) {
emit_instr(ctx, slti, MIPS_R_AT, dst, (int)t64s);
src = MIPS_R_AT;
Expand All @@ -1197,22 +1198,22 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
case BPF_JMP | BPF_JGE | BPF_K:
case BPF_JMP | BPF_JLT | BPF_K:
case BPF_JMP | BPF_JLE | BPF_K:
cmp_eq = (BPF_OP(insn->code) == BPF_JGE);
cmp_eq = (bpf_op == BPF_JGE);
dst = ebpf_to_mips_reg(ctx, insn, dst_reg_fp_ok);
if (dst < 0)
return dst;
/*
* only "LT" compare available, so we must use imm + 1
* to generate "GT" and imm -1 to generate LE
*/
if (BPF_OP(insn->code) == BPF_JGT)
if (bpf_op == BPF_JGT)
t64s = (u64)(u32)(insn->imm) + 1;
else if (BPF_OP(insn->code) == BPF_JLE)
else if (bpf_op == BPF_JLE)
t64s = (u64)(u32)(insn->imm) + 1;
else
t64s = (u64)(u32)(insn->imm);

cmp_eq = BPF_OP(insn->code) == BPF_JGT || BPF_OP(insn->code) == BPF_JGE;
cmp_eq = bpf_op == BPF_JGT || bpf_op == BPF_JGE;

emit_const_to_reg(ctx, MIPS_R_AT, (u64)t64s);
emit_instr(ctx, sltu, MIPS_R_AT, dst, MIPS_R_AT);
Expand Down

0 comments on commit 6035b3f

Please sign in to comment.