[PATCH] mips: filter: fix build error in BPF JIT

From: Daniel Borkmann
Date: Tue Jun 17 2014 - 05:48:28 EST

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Guenter reported that on MIPS, the following build error occurs when
BPF JIT is enabled:

mips: allmodconfig fails in 3.16-rc1 with lots of undefined symbols.

arch/mips/net/bpf_jit.c: In function 'is_load_to_a':
arch/mips/net/bpf_jit.c:559:7: error: 'BPF_S_LD_W_LEN' undeclared (first use in this function)
arch/mips/net/bpf_jit.c:559:7: note: each undeclared identifier is reported only once for each function it appears in
arch/mips/net/bpf_jit.c:560:7: error: 'BPF_S_LD_W_ABS' undeclared (first use in this function)
[...]

The reason behind this is that 3480593131e0 ("net: filter: get rid of
BPF_S_* enum") was routed via net-next tree, that takes all BPF-related
changes, at a time where MIPS BPF JIT was not part of net-next, while
c6610de353da ("MIPS: net: Add BPF JIT") was routed via mips arch tree
and went into mainline within the same merge window. Thus, fix it up by
converting BPF_S_* in a similar fashion as in 3480593131e0 for MIPS.

Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Daniel Borkmann <dborkman@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxxxx>
Cc: Markos Chandras <markos.chandras@xxxxxxxxxx>
---
arch/mips/net/bpf_jit.c | 143 +++++++++++++++++++++++-------------------------
1 file changed, 69 insertions(+), 74 deletions(-)

diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c
index a67b975..f7c2064 100644
--- a/arch/mips/net/bpf_jit.c
+++ b/arch/mips/net/bpf_jit.c
@@ -556,18 +556,10 @@ static inline void update_on_xread(struct jit_ctx *ctx)
static bool is_load_to_a(u16 inst)
{
switch (inst) {
- case BPF_S_LD_W_LEN:
- case BPF_S_LD_W_ABS:
- case BPF_S_LD_H_ABS:
- case BPF_S_LD_B_ABS:
- case BPF_S_ANC_CPU:
- case BPF_S_ANC_IFINDEX:
- case BPF_S_ANC_MARK:
- case BPF_S_ANC_PROTOCOL:
- case BPF_S_ANC_RXHASH:
- case BPF_S_ANC_VLAN_TAG:
- case BPF_S_ANC_VLAN_TAG_PRESENT:
- case BPF_S_ANC_QUEUE:
+ case BPF_LD | BPF_W | BPF_LEN:
+ case BPF_LD | BPF_W | BPF_ABS:
+ case BPF_LD | BPF_H | BPF_ABS:
+ case BPF_LD | BPF_B | BPF_ABS:
return true;
default:
return false;
@@ -709,7 +701,7 @@ static void build_prologue(struct jit_ctx *ctx)
emit_jit_reg_move(r_X, r_zero, ctx);

/* Do not leak kernel data to userspace */
- if ((first_inst != BPF_S_RET_K) && !(is_load_to_a(first_inst)))
+ if ((first_inst != (BPF_RET | BPF_K)) && !(is_load_to_a(first_inst)))
emit_jit_reg_move(r_A, r_zero, ctx);
}

@@ -783,41 +775,44 @@ static int build_body(struct jit_ctx *ctx)
u32 k, b_off __maybe_unused;

for (i = 0; i < prog->len; i++) {
+ u16 code;
+
inst = &(prog->insns[i]);
pr_debug("%s: code->0x%02x, jt->0x%x, jf->0x%x, k->0x%x\n",
__func__, inst->code, inst->jt, inst->jf, inst->k);
k = inst->k;
+ code = bpf_anc_helper(inst);

if (ctx->target == NULL)
ctx->offsets[i] = ctx->idx * 4;

- switch (inst->code) {
- case BPF_S_LD_IMM:
+ switch (code) {
+ case BPF_LD | BPF_IMM:
/* A <- k ==> li r_A, k */
ctx->flags |= SEEN_A;
emit_load_imm(r_A, k, ctx);
break;
- case BPF_S_LD_W_LEN:
+ case BPF_LD | BPF_W | BPF_LEN:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
/* A <- len ==> lw r_A, offset(skb) */
ctx->flags |= SEEN_SKB | SEEN_A;
off = offsetof(struct sk_buff, len);
emit_load(r_A, r_skb, off, ctx);
break;
- case BPF_S_LD_MEM:
+ case BPF_LD | BPF_MEM:
/* A <- M[k] ==> lw r_A, offset(M) */
ctx->flags |= SEEN_MEM | SEEN_A;
emit_load(r_A, r_M, SCRATCH_OFF(k), ctx);
break;
- case BPF_S_LD_W_ABS:
+ case BPF_LD | BPF_W | BPF_ABS:
/* A <- P[k:4] */
load_order = 2;
goto load;
- case BPF_S_LD_H_ABS:
+ case BPF_LD | BPF_H | BPF_ABS:
/* A <- P[k:2] */
load_order = 1;
goto load;
- case BPF_S_LD_B_ABS:
+ case BPF_LD | BPF_B | BPF_ABS:
/* A <- P[k:1] */
load_order = 0;
load:
@@ -852,15 +847,15 @@ load_common:
emit_b(b_imm(prog->len, ctx), ctx);
emit_reg_move(r_ret, r_zero, ctx);
break;
- case BPF_S_LD_W_IND:
+ case BPF_LD | BPF_W | BPF_IND:
/* A <- P[X + k:4] */
load_order = 2;
goto load_ind;
- case BPF_S_LD_H_IND:
+ case BPF_LD | BPF_H | BPF_IND:
/* A <- P[X + k:2] */
load_order = 1;
goto load_ind;
- case BPF_S_LD_B_IND:
+ case BPF_LD | BPF_B | BPF_IND:
/* A <- P[X + k:1] */
load_order = 0;
load_ind:
@@ -868,23 +863,23 @@ load_ind:
ctx->flags |= SEEN_OFF | SEEN_X;
emit_addiu(r_off, r_X, k, ctx);
goto load_common;
- case BPF_S_LDX_IMM:
+ case BPF_LDX | BPF_IMM:
/* X <- k */
ctx->flags |= SEEN_X;
emit_load_imm(r_X, k, ctx);
break;
- case BPF_S_LDX_MEM:
+ case BPF_LDX | BPF_MEM:
/* X <- M[k] */
ctx->flags |= SEEN_X | SEEN_MEM;
emit_load(r_X, r_M, SCRATCH_OFF(k), ctx);
break;
- case BPF_S_LDX_W_LEN:
+ case BPF_LDX | BPF_W | BPF_LEN:
/* X <- len */
ctx->flags |= SEEN_X | SEEN_SKB;
off = offsetof(struct sk_buff, len);
emit_load(r_X, r_skb, off, ctx);
break;
- case BPF_S_LDX_B_MSH:
+ case BPF_LDX | BPF_B | BPF_MSH:
/* X <- 4 * (P[k:1] & 0xf) */
ctx->flags |= SEEN_X | SEEN_CALL | SEEN_S0 | SEEN_SKB;
/* Load offset to a1 */
@@ -917,50 +912,50 @@ load_ind:
emit_b(b_imm(prog->len, ctx), ctx);
emit_load_imm(r_ret, 0, ctx); /* delay slot */
break;
- case BPF_S_ST:
+ case BPF_ST:
/* M[k] <- A */
ctx->flags |= SEEN_MEM | SEEN_A;
emit_store(r_A, r_M, SCRATCH_OFF(k), ctx);
break;
- case BPF_S_STX:
+ case BPF_STX:
/* M[k] <- X */
ctx->flags |= SEEN_MEM | SEEN_X;
emit_store(r_X, r_M, SCRATCH_OFF(k), ctx);
break;
- case BPF_S_ALU_ADD_K:
+ case BPF_ALU | BPF_ADD | BPF_K:
/* A += K */
ctx->flags |= SEEN_A;
emit_addiu(r_A, r_A, k, ctx);
break;
- case BPF_S_ALU_ADD_X:
+ case BPF_ALU | BPF_ADD | BPF_X:
/* A += X */
ctx->flags |= SEEN_A | SEEN_X;
emit_addu(r_A, r_A, r_X, ctx);
break;
- case BPF_S_ALU_SUB_K:
+ case BPF_ALU | BPF_SUB | BPF_K:
/* A -= K */
ctx->flags |= SEEN_A;
emit_addiu(r_A, r_A, -k, ctx);
break;
- case BPF_S_ALU_SUB_X:
+ case BPF_ALU | BPF_SUB | BPF_X:
/* A -= X */
ctx->flags |= SEEN_A | SEEN_X;
emit_subu(r_A, r_A, r_X, ctx);
break;
- case BPF_S_ALU_MUL_K:
+ case BPF_ALU | BPF_MUL | BPF_K:
/* A *= K */
/* Load K to scratch register before MUL */
ctx->flags |= SEEN_A | SEEN_S0;
emit_load_imm(r_s0, k, ctx);
emit_mul(r_A, r_A, r_s0, ctx);
break;
- case BPF_S_ALU_MUL_X:
+ case BPF_ALU | BPF_MUL | BPF_X:
/* A *= X */
update_on_xread(ctx);
ctx->flags |= SEEN_A | SEEN_X;
emit_mul(r_A, r_A, r_X, ctx);
break;
- case BPF_S_ALU_DIV_K:
+ case BPF_ALU | BPF_DIV | BPF_K:
/* A /= k */
if (k == 1)
break;
@@ -973,7 +968,7 @@ load_ind:
emit_load_imm(r_s0, k, ctx);
emit_div(r_A, r_s0, ctx);
break;
- case BPF_S_ALU_MOD_K:
+ case BPF_ALU | BPF_MOD | BPF_K:
/* A %= k */
if (k == 1 || optimize_div(&k)) {
ctx->flags |= SEEN_A;
@@ -984,7 +979,7 @@ load_ind:
emit_mod(r_A, r_s0, ctx);
}
break;
- case BPF_S_ALU_DIV_X:
+ case BPF_ALU | BPF_DIV | BPF_X:
/* A /= X */
update_on_xread(ctx);
ctx->flags |= SEEN_X | SEEN_A;
@@ -994,7 +989,7 @@ load_ind:
emit_load_imm(r_val, 0, ctx); /* delay slot */
emit_div(r_A, r_X, ctx);
break;
- case BPF_S_ALU_MOD_X:
+ case BPF_ALU | BPF_MOD | BPF_X:
/* A %= X */
update_on_xread(ctx);
ctx->flags |= SEEN_X | SEEN_A;
@@ -1004,94 +999,94 @@ load_ind:
emit_load_imm(r_val, 0, ctx); /* delay slot */
emit_mod(r_A, r_X, ctx);
break;
- case BPF_S_ALU_OR_K:
+ case BPF_ALU | BPF_OR | BPF_K:
/* A |= K */
ctx->flags |= SEEN_A;
emit_ori(r_A, r_A, k, ctx);
break;
- case BPF_S_ALU_OR_X:
+ case BPF_ALU | BPF_OR | BPF_X:
/* A |= X */
update_on_xread(ctx);
ctx->flags |= SEEN_A;
emit_ori(r_A, r_A, r_X, ctx);
break;
- case BPF_S_ALU_XOR_K:
+ case BPF_ALU | BPF_XOR | BPF_K:
/* A ^= k */
ctx->flags |= SEEN_A;
emit_xori(r_A, r_A, k, ctx);
break;
- case BPF_S_ANC_ALU_XOR_X:
- case BPF_S_ALU_XOR_X:
+ case BPF_ANC | SKF_AD_ALU_XOR_X:
+ case BPF_ALU | BPF_XOR | BPF_X:
/* A ^= X */
update_on_xread(ctx);
ctx->flags |= SEEN_A;
emit_xor(r_A, r_A, r_X, ctx);
break;
- case BPF_S_ALU_AND_K:
+ case BPF_ALU | BPF_AND | BPF_K:
/* A &= K */
ctx->flags |= SEEN_A;
emit_andi(r_A, r_A, k, ctx);
break;
- case BPF_S_ALU_AND_X:
+ case BPF_ALU | BPF_AND | BPF_X:
/* A &= X */
update_on_xread(ctx);
ctx->flags |= SEEN_A | SEEN_X;
emit_and(r_A, r_A, r_X, ctx);
break;
- case BPF_S_ALU_LSH_K:
+ case BPF_ALU | BPF_LSH | BPF_K:
/* A <<= K */
ctx->flags |= SEEN_A;
emit_sll(r_A, r_A, k, ctx);
break;
- case BPF_S_ALU_LSH_X:
+ case BPF_ALU | BPF_LSH | BPF_X:
/* A <<= X */
ctx->flags |= SEEN_A | SEEN_X;
update_on_xread(ctx);
emit_sllv(r_A, r_A, r_X, ctx);
break;
- case BPF_S_ALU_RSH_K:
+ case BPF_ALU | BPF_RSH | BPF_K:
/* A >>= K */
ctx->flags |= SEEN_A;
emit_srl(r_A, r_A, k, ctx);
break;
- case BPF_S_ALU_RSH_X:
+ case BPF_ALU | BPF_RSH | BPF_X:
ctx->flags |= SEEN_A | SEEN_X;
update_on_xread(ctx);
emit_srlv(r_A, r_A, r_X, ctx);
break;
- case BPF_S_ALU_NEG:
+ case BPF_ALU | BPF_NEG:
/* A = -A */
ctx->flags |= SEEN_A;
emit_neg(r_A, ctx);
break;
- case BPF_S_JMP_JA:
+ case BPF_JMP | BPF_JA:
/* pc += K */
emit_b(b_imm(i + k + 1, ctx), ctx);
emit_nop(ctx);
break;
- case BPF_S_JMP_JEQ_K:
+ case BPF_JMP | BPF_JEQ | BPF_K:
/* pc += ( A == K ) ? pc->jt : pc->jf */
condt = MIPS_COND_EQ | MIPS_COND_K;
goto jmp_cmp;
- case BPF_S_JMP_JEQ_X:
+ case BPF_JMP | BPF_JEQ | BPF_X:
ctx->flags |= SEEN_X;
/* pc += ( A == X ) ? pc->jt : pc->jf */
condt = MIPS_COND_EQ | MIPS_COND_X;
goto jmp_cmp;
- case BPF_S_JMP_JGE_K:
+ case BPF_JMP | BPF_JGE | BPF_K:
/* pc += ( A >= K ) ? pc->jt : pc->jf */
condt = MIPS_COND_GE | MIPS_COND_K;
goto jmp_cmp;
- case BPF_S_JMP_JGE_X:
+ case BPF_JMP | BPF_JGE | BPF_X:
ctx->flags |= SEEN_X;
/* pc += ( A >= X ) ? pc->jt : pc->jf */
condt = MIPS_COND_GE | MIPS_COND_X;
goto jmp_cmp;
- case BPF_S_JMP_JGT_K:
+ case BPF_JMP | BPF_JGT | BPF_K:
/* pc += ( A > K ) ? pc->jt : pc->jf */
condt = MIPS_COND_GT | MIPS_COND_K;
goto jmp_cmp;
- case BPF_S_JMP_JGT_X:
+ case BPF_JMP | BPF_JGT | BPF_X:
ctx->flags |= SEEN_X;
/* pc += ( A > X ) ? pc->jt : pc->jf */
condt = MIPS_COND_GT | MIPS_COND_X;
@@ -1167,7 +1162,7 @@ jmp_cmp:
}
}
break;
- case BPF_S_JMP_JSET_K:
+ case BPF_JMP | BPF_JSET | BPF_K:
ctx->flags |= SEEN_S0 | SEEN_S1 | SEEN_A;
/* pc += (A & K) ? pc -> jt : pc -> jf */
emit_load_imm(r_s1, k, ctx);
@@ -1181,7 +1176,7 @@ jmp_cmp:
emit_b(b_off, ctx);
emit_nop(ctx);
break;
- case BPF_S_JMP_JSET_X:
+ case BPF_JMP | BPF_JSET | BPF_X:
ctx->flags |= SEEN_S0 | SEEN_X | SEEN_A;
/* pc += (A & X) ? pc -> jt : pc -> jf */
emit_and(r_s0, r_A, r_X, ctx);
@@ -1194,7 +1189,7 @@ jmp_cmp:
emit_b(b_off, ctx);
emit_nop(ctx);
break;
- case BPF_S_RET_A:
+ case BPF_RET | BPF_A:
ctx->flags |= SEEN_A;
if (i != prog->len - 1)
/*
@@ -1204,7 +1199,7 @@ jmp_cmp:
emit_b(b_imm(prog->len, ctx), ctx);
emit_reg_move(r_ret, r_A, ctx); /* delay slot */
break;
- case BPF_S_RET_K:
+ case BPF_RET | BPF_K:
/*
* It can emit two instructions so it does not fit on
* the delay slot.
@@ -1219,19 +1214,19 @@ jmp_cmp:
emit_nop(ctx);
}
break;
- case BPF_S_MISC_TAX:
+ case BPF_MISC | BPF_TAX:
/* X = A */
ctx->flags |= SEEN_X | SEEN_A;
emit_jit_reg_move(r_X, r_A, ctx);
break;
- case BPF_S_MISC_TXA:
+ case BPF_MISC | BPF_TXA:
/* A = X */
ctx->flags |= SEEN_A | SEEN_X;
update_on_xread(ctx);
emit_jit_reg_move(r_A, r_X, ctx);
break;
/* AUX */
- case BPF_S_ANC_PROTOCOL:
+ case BPF_ANC | SKF_AD_PROTOCOL:
/* A = ntohs(skb->protocol */
ctx->flags |= SEEN_SKB | SEEN_OFF | SEEN_A;
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
@@ -1256,7 +1251,7 @@ jmp_cmp:
}
#endif
break;
- case BPF_S_ANC_CPU:
+ case BPF_ANC | SKF_AD_CPU:
ctx->flags |= SEEN_A | SEEN_OFF;
/* A = current_thread_info()->cpu */
BUILD_BUG_ON(FIELD_SIZEOF(struct thread_info,
@@ -1265,7 +1260,7 @@ jmp_cmp:
/* $28/gp points to the thread_info struct */
emit_load(r_A, 28, off, ctx);
break;
- case BPF_S_ANC_IFINDEX:
+ case BPF_ANC | SKF_AD_IFINDEX:
/* A = skb->dev->ifindex */
ctx->flags |= SEEN_SKB | SEEN_A | SEEN_S0;
off = offsetof(struct sk_buff, dev);
@@ -1279,31 +1274,31 @@ jmp_cmp:
off = offsetof(struct net_device, ifindex);
emit_load(r_A, r_s0, off, ctx);
break;
- case BPF_S_ANC_MARK:
+ case BPF_ANC | SKF_AD_MARK:
ctx->flags |= SEEN_SKB | SEEN_A;
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
off = offsetof(struct sk_buff, mark);
emit_load(r_A, r_skb, off, ctx);
break;
- case BPF_S_ANC_RXHASH:
+ case BPF_ANC | SKF_AD_RXHASH:
ctx->flags |= SEEN_SKB | SEEN_A;
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
off = offsetof(struct sk_buff, hash);
emit_load(r_A, r_skb, off, ctx);
break;
- case BPF_S_ANC_VLAN_TAG:
- case BPF_S_ANC_VLAN_TAG_PRESENT:
+ case BPF_ANC | SKF_AD_VLAN_TAG:
+ case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT:
ctx->flags |= SEEN_SKB | SEEN_S0 | SEEN_A;
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
vlan_tci) != 2);
off = offsetof(struct sk_buff, vlan_tci);
emit_half_load(r_s0, r_skb, off, ctx);
- if (inst->code == BPF_S_ANC_VLAN_TAG)
+ if (code == (BPF_ANC | SKF_AD_VLAN_TAG))
emit_and(r_A, r_s0, VLAN_VID_MASK, ctx);
else
emit_and(r_A, r_s0, VLAN_TAG_PRESENT, ctx);
break;
- case BPF_S_ANC_PKTTYPE:
+ case BPF_ANC | SKF_AD_PKTTYPE:
off = pkt_type_offset();

if (off < 0)
@@ -1312,7 +1307,7 @@ jmp_cmp:
/* Keep only the last 3 bits */
emit_andi(r_A, r_tmp, PKT_TYPE_MAX, ctx);
break;
- case BPF_S_ANC_QUEUE:
+ case BPF_ANC | SKF_AD_QUEUE:
ctx->flags |= SEEN_SKB | SEEN_A;
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
queue_mapping) != 2);
--
1.7.11.7

--------------000900030008080307080608--
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