net: filter: get rid of BPF_S_* enum

This patch finally allows us to get rid of the BPF_S_* enum.
Currently, the code performs unnecessary encode and decode
workarounds in seccomp and filter migration itself when a filter
is being attached in order to overcome BPF_S_* encoding which
is not used anymore by the new interpreter resp. JIT compilers.

Keeping it around would mean that also in future we would need
to extend and maintain this enum and related encoders/decoders.
We can get rid of all that and save us these operations during
filter attaching. Naturally, also JIT compilers need to be updated
by this.

Before JIT conversion is being done, each compiler checks if A
is being loaded at startup to obtain information if it needs to
emit instructions to clear A first. Since BPF extensions are a
subset of BPF_LD | BPF_{W,H,B} | BPF_ABS variants, case statements
for extensions can be removed at that point. To ease and minimalize
code changes in the classic JITs, we have introduced bpf_anc_helper().

Tested with test_bpf on x86_64 (JIT, int), s390x (JIT, int),
arm (JIT, int), i368 (int), ppc64 (JIT, int); for sparc we
unfortunately didn't have access, but changes are analogous to
the rest.

Joint work with Alexei Starovoitov.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mircea Gherzan <mgherzan@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Acked-by: Chema Gonzalez <chemag@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 76 insertions, 83 deletions

diff --git a/arch/powerpc/net/bpf_jit_64.S b/arch/powerpc/net/bpf_jit_64.S
index e76eba7..8f87d92 100644
--- a/arch/powerpc/net/bpf_jit_64.S
+++ b/arch/powerpc/net/bpf_jit_64.S
@@ -78,7 +78,7 @@ sk_load_byte_positive_offset:
 	blr
 
 /*
- * BPF_S_LDX_B_MSH: ldxb  4*([offset]&0xf)
+ * BPF_LDX | BPF_B | BPF_MSH: ldxb  4*([offset]&0xf)
  * r_addr is the offset value
  */
 	.globl sk_load_byte_msh
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index 808ce1c..6dcdade 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -79,19 +79,11 @@ static void bpf_jit_build_prologue(struct sk_filter *fp, u32 *image,
 	}
 
 	switch (filter[0].code) {
-	case BPF_S_RET_K:
-	case BPF_S_LD_W_LEN:
-	case BPF_S_ANC_PROTOCOL:
-	case BPF_S_ANC_IFINDEX:
-	case BPF_S_ANC_MARK:
-	case BPF_S_ANC_RXHASH:
-	case BPF_S_ANC_VLAN_TAG:
-	case BPF_S_ANC_VLAN_TAG_PRESENT:
-	case BPF_S_ANC_CPU:
-	case BPF_S_ANC_QUEUE:
-	case BPF_S_LD_W_ABS:
-	case BPF_S_LD_H_ABS:
-	case BPF_S_LD_B_ABS:
+	case BPF_RET | BPF_K:
+	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:
 		/* first instruction sets A register (or is RET 'constant') */
 		break;
 	default:
@@ -144,6 +136,7 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
 
 	for (i = 0; i < flen; i++) {
 		unsigned int K = filter[i].k;
+		u16 code = bpf_anc_helper(&filter[i]);
 
 		/*
 		 * addrs[] maps a BPF bytecode address into a real offset from
@@ -151,35 +144,35 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
 		 */
 		addrs[i] = ctx->idx * 4;
 
-		switch (filter[i].code) {
+		switch (code) {
 			/*** ALU ops ***/
-		case BPF_S_ALU_ADD_X: /* A += X; */
+		case BPF_ALU | BPF_ADD | BPF_X: /* A += X; */
 			ctx->seen |= SEEN_XREG;
 			PPC_ADD(r_A, r_A, r_X);
 			break;
-		case BPF_S_ALU_ADD_K: /* A += K; */
+		case BPF_ALU | BPF_ADD | BPF_K: /* A += K; */
 			if (!K)
 				break;
 			PPC_ADDI(r_A, r_A, IMM_L(K));
 			if (K >= 32768)
 				PPC_ADDIS(r_A, r_A, IMM_HA(K));
 			break;
-		case BPF_S_ALU_SUB_X: /* A -= X; */
+		case BPF_ALU | BPF_SUB | BPF_X: /* A -= X; */
 			ctx->seen |= SEEN_XREG;
 			PPC_SUB(r_A, r_A, r_X);
 			break;
-		case BPF_S_ALU_SUB_K: /* A -= K */
+		case BPF_ALU | BPF_SUB | BPF_K: /* A -= K */
 			if (!K)
 				break;
 			PPC_ADDI(r_A, r_A, IMM_L(-K));
 			if (K >= 32768)
 				PPC_ADDIS(r_A, r_A, IMM_HA(-K));
 			break;
-		case BPF_S_ALU_MUL_X: /* A *= X; */
+		case BPF_ALU | BPF_MUL | BPF_X: /* A *= X; */
 			ctx->seen |= SEEN_XREG;
 			PPC_MUL(r_A, r_A, r_X);
 			break;
-		case BPF_S_ALU_MUL_K: /* A *= K */
+		case BPF_ALU | BPF_MUL | BPF_K: /* A *= K */
 			if (K < 32768)
 				PPC_MULI(r_A, r_A, K);
 			else {
@@ -187,7 +180,7 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
 				PPC_MUL(r_A, r_A, r_scratch1);
 			}
 			break;
-		case BPF_S_ALU_MOD_X: /* A %= X; */
+		case BPF_ALU | BPF_MOD | BPF_X: /* A %= X; */
 			ctx->seen |= SEEN_XREG;
 			PPC_CMPWI(r_X, 0);
 			if (ctx->pc_ret0 != -1) {
@@ -201,13 +194,13 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
 			PPC_MUL(r_scratch1, r_X, r_scratch1);
 			PPC_SUB(r_A, r_A, r_scratch1);
 			break;
-		case BPF_S_ALU_MOD_K: /* A %= K; */
+		case BPF_ALU | BPF_MOD | BPF_K: /* A %= K; */
 			PPC_LI32(r_scratch2, K);
 			PPC_DIVWU(r_scratch1, r_A, r_scratch2);
 			PPC_MUL(r_scratch1, r_scratch2, r_scratch1);
 			PPC_SUB(r_A, r_A, r_scratch1);
 			break;
-		case BPF_S_ALU_DIV_X: /* A /= X; */
+		case BPF_ALU | BPF_DIV | BPF_X: /* A /= X; */
 			ctx->seen |= SEEN_XREG;
 			PPC_CMPWI(r_X, 0);
 			if (ctx->pc_ret0 != -1) {
@@ -223,17 +216,17 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
 			}
 			PPC_DIVWU(r_A, r_A, r_X);
 			break;
-		case BPF_S_ALU_DIV_K: /* A /= K */
+		case BPF_ALU | BPF_DIV | BPF_K: /* A /= K */
 			if (K == 1)
 				break;
 			PPC_LI32(r_scratch1, K);
 			PPC_DIVWU(r_A, r_A, r_scratch1);
 			break;
-		case BPF_S_ALU_AND_X:
+		case BPF_ALU | BPF_AND | BPF_X:
 			ctx->seen |= SEEN_XREG;
 			PPC_AND(r_A, r_A, r_X);
 			break;
-		case BPF_S_ALU_AND_K:
+		case BPF_ALU | BPF_AND | BPF_K:
 			if (!IMM_H(K))
 				PPC_ANDI(r_A, r_A, K);
 			else {
@@ -241,51 +234,51 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
 				PPC_AND(r_A, r_A, r_scratch1);
 			}
 			break;
-		case BPF_S_ALU_OR_X:
+		case BPF_ALU | BPF_OR | BPF_X:
 			ctx->seen |= SEEN_XREG;
 			PPC_OR(r_A, r_A, r_X);
 			break;
-		case BPF_S_ALU_OR_K:
+		case BPF_ALU | BPF_OR | BPF_K:
 			if (IMM_L(K))
 				PPC_ORI(r_A, r_A, IMM_L(K));
 			if (K >= 65536)
 				PPC_ORIS(r_A, r_A, IMM_H(K));
 			break;
-		case BPF_S_ANC_ALU_XOR_X:
-		case BPF_S_ALU_XOR_X: /* A ^= X */
+		case BPF_ANC | SKF_AD_ALU_XOR_X:
+		case BPF_ALU | BPF_XOR | BPF_X: /* A ^= X */
 			ctx->seen |= SEEN_XREG;
 			PPC_XOR(r_A, r_A, r_X);
 			break;
-		case BPF_S_ALU_XOR_K: /* A ^= K */
+		case BPF_ALU | BPF_XOR | BPF_K: /* A ^= K */
 			if (IMM_L(K))
 				PPC_XORI(r_A, r_A, IMM_L(K));
 			if (K >= 65536)
 				PPC_XORIS(r_A, r_A, IMM_H(K));
 			break;
-		case BPF_S_ALU_LSH_X: /* A <<= X; */
+		case BPF_ALU | BPF_LSH | BPF_X: /* A <<= X; */
 			ctx->seen |= SEEN_XREG;
 			PPC_SLW(r_A, r_A, r_X);
 			break;
-		case BPF_S_ALU_LSH_K:
+		case BPF_ALU | BPF_LSH | BPF_K:
 			if (K == 0)
 				break;
 			else
 				PPC_SLWI(r_A, r_A, K);
 			break;
-		case BPF_S_ALU_RSH_X: /* A >>= X; */
+		case BPF_ALU | BPF_RSH | BPF_X: /* A >>= X; */
 			ctx->seen |= SEEN_XREG;
 			PPC_SRW(r_A, r_A, r_X);
 			break;
-		case BPF_S_ALU_RSH_K: /* A >>= K; */
+		case BPF_ALU | BPF_RSH | BPF_K: /* A >>= K; */
 			if (K == 0)
 				break;
 			else
 				PPC_SRWI(r_A, r_A, K);
 			break;
-		case BPF_S_ALU_NEG:
+		case BPF_ALU | BPF_NEG:
 			PPC_NEG(r_A, r_A);
 			break;
-		case BPF_S_RET_K:
+		case BPF_RET | BPF_K:
 			PPC_LI32(r_ret, K);
 			if (!K) {
 				if (ctx->pc_ret0 == -1)
@@ -312,7 +305,7 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
 					PPC_BLR();
 			}
 			break;
-		case BPF_S_RET_A:
+		case BPF_RET | BPF_A:
 			PPC_MR(r_ret, r_A);
 			if (i != flen - 1) {
 				if (ctx->seen)
@@ -321,53 +314,53 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
 					PPC_BLR();
 			}
 			break;
-		case BPF_S_MISC_TAX: /* X = A */
+		case BPF_MISC | BPF_TAX: /* X = A */
 			PPC_MR(r_X, r_A);
 			break;
-		case BPF_S_MISC_TXA: /* A = X */
+		case BPF_MISC | BPF_TXA: /* A = X */
 			ctx->seen |= SEEN_XREG;
 			PPC_MR(r_A, r_X);
 			break;
 
 			/*** Constant loads/M[] access ***/
-		case BPF_S_LD_IMM: /* A = K */
+		case BPF_LD | BPF_IMM: /* A = K */
 			PPC_LI32(r_A, K);
 			break;
-		case BPF_S_LDX_IMM: /* X = K */
+		case BPF_LDX | BPF_IMM: /* X = K */
 			PPC_LI32(r_X, K);
 			break;
-		case BPF_S_LD_MEM: /* A = mem[K] */
+		case BPF_LD | BPF_MEM: /* A = mem[K] */
 			PPC_MR(r_A, r_M + (K & 0xf));
 			ctx->seen |= SEEN_MEM | (1<<(K & 0xf));
 			break;
-		case BPF_S_LDX_MEM: /* X = mem[K] */
+		case BPF_LDX | BPF_MEM: /* X = mem[K] */
 			PPC_MR(r_X, r_M + (K & 0xf));
 			ctx->seen |= SEEN_MEM | (1<<(K & 0xf));
 			break;
-		case BPF_S_ST: /* mem[K] = A */
+		case BPF_ST: /* mem[K] = A */
 			PPC_MR(r_M + (K & 0xf), r_A);
 			ctx->seen |= SEEN_MEM | (1<<(K & 0xf));
 			break;
-		case BPF_S_STX: /* mem[K] = X */
+		case BPF_STX: /* mem[K] = X */
 			PPC_MR(r_M + (K & 0xf), r_X);
 			ctx->seen |= SEEN_XREG | SEEN_MEM | (1<<(K & 0xf));
 			break;
-		case BPF_S_LD_W_LEN: /*	A = skb->len; */
+		case BPF_LD | BPF_W | BPF_LEN: /*	A = skb->len; */
 			BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
 			PPC_LWZ_OFFS(r_A, r_skb, offsetof(struct sk_buff, len));
 			break;
-		case BPF_S_LDX_W_LEN: /* X = skb->len; */
+		case BPF_LDX | BPF_W | BPF_LEN: /* X = skb->len; */
 			PPC_LWZ_OFFS(r_X, r_skb, offsetof(struct sk_buff, len));
 			break;
 
 			/*** Ancillary info loads ***/
-		case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
+		case BPF_ANC | SKF_AD_PROTOCOL: /* A = ntohs(skb->protocol); */
 			BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
 						  protocol) != 2);
 			PPC_NTOHS_OFFS(r_A, r_skb, offsetof(struct sk_buff,
 							    protocol));
 			break;
-		case BPF_S_ANC_IFINDEX:
+		case BPF_ANC | SKF_AD_IFINDEX:
 			PPC_LD_OFFS(r_scratch1, r_skb, offsetof(struct sk_buff,
 								dev));
 			PPC_CMPDI(r_scratch1, 0);
@@ -384,33 +377,33 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
 			PPC_LWZ_OFFS(r_A, r_scratch1,
 				     offsetof(struct net_device, ifindex));
 			break;
-		case BPF_S_ANC_MARK:
+		case BPF_ANC | SKF_AD_MARK:
 			BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
 			PPC_LWZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
 							  mark));
 			break;
-		case BPF_S_ANC_RXHASH:
+		case BPF_ANC | SKF_AD_RXHASH:
 			BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
 			PPC_LWZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
 							  hash));
 			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:
 			BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
 			PPC_LHZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
 							  vlan_tci));
-			if (filter[i].code == BPF_S_ANC_VLAN_TAG)
+			if (code == (BPF_ANC | SKF_AD_VLAN_TAG))
 				PPC_ANDI(r_A, r_A, VLAN_VID_MASK);
 			else
 				PPC_ANDI(r_A, r_A, VLAN_TAG_PRESENT);
 			break;
-		case BPF_S_ANC_QUEUE:
+		case BPF_ANC | SKF_AD_QUEUE:
 			BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
 						  queue_mapping) != 2);
 			PPC_LHZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
 							  queue_mapping));
 			break;
-		case BPF_S_ANC_CPU:
+		case BPF_ANC | SKF_AD_CPU:
 #ifdef CONFIG_SMP
 			/*
 			 * PACA ptr is r13:
@@ -426,13 +419,13 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
 			break;
 
 			/*** Absolute loads from packet header/data ***/
-		case BPF_S_LD_W_ABS:
+		case BPF_LD | BPF_W | BPF_ABS:
 			func = CHOOSE_LOAD_FUNC(K, sk_load_word);
 			goto common_load;
-		case BPF_S_LD_H_ABS:
+		case BPF_LD | BPF_H | BPF_ABS:
 			func = CHOOSE_LOAD_FUNC(K, sk_load_half);
 			goto common_load;
-		case BPF_S_LD_B_ABS:
+		case BPF_LD | BPF_B | BPF_ABS:
 			func = CHOOSE_LOAD_FUNC(K, sk_load_byte);
 		common_load:
 			/* Load from [K]. */
@@ -449,13 +442,13 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
 			break;
 
 			/*** Indirect loads from packet header/data ***/
-		case BPF_S_LD_W_IND:
+		case BPF_LD | BPF_W | BPF_IND:
 			func = sk_load_word;
 			goto common_load_ind;
-		case BPF_S_LD_H_IND:
+		case BPF_LD | BPF_H | BPF_IND:
 			func = sk_load_half;
 			goto common_load_ind;
-		case BPF_S_LD_B_IND:
+		case BPF_LD | BPF_B | BPF_IND:
 			func = sk_load_byte;
 		common_load_ind:
 			/*
@@ -473,31 +466,31 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
 			PPC_BCC(COND_LT, exit_addr);
 			break;
 
-		case BPF_S_LDX_B_MSH:
+		case BPF_LDX | BPF_B | BPF_MSH:
 			func = CHOOSE_LOAD_FUNC(K, sk_load_byte_msh);
 			goto common_load;
 			break;
 
 			/*** Jump and branches ***/
-		case BPF_S_JMP_JA:
+		case BPF_JMP | BPF_JA:
 			if (K != 0)
 				PPC_JMP(addrs[i + 1 + K]);
 			break;
 
-		case BPF_S_JMP_JGT_K:
-		case BPF_S_JMP_JGT_X:
+		case BPF_JMP | BPF_JGT | BPF_K:
+		case BPF_JMP | BPF_JGT | BPF_X:
 			true_cond = COND_GT;
 			goto cond_branch;
-		case BPF_S_JMP_JGE_K:
-		case BPF_S_JMP_JGE_X:
+		case BPF_JMP | BPF_JGE | BPF_K:
+		case BPF_JMP | BPF_JGE | BPF_X:
 			true_cond = COND_GE;
 			goto cond_branch;
-		case BPF_S_JMP_JEQ_K:
-		case BPF_S_JMP_JEQ_X:
+		case BPF_JMP | BPF_JEQ | BPF_K:
+		case BPF_JMP | BPF_JEQ | BPF_X:
 			true_cond = COND_EQ;
 			goto cond_branch;
-		case BPF_S_JMP_JSET_K:
-		case BPF_S_JMP_JSET_X:
+		case BPF_JMP | BPF_JSET | BPF_K:
+		case BPF_JMP | BPF_JSET | BPF_X:
 			true_cond = COND_NE;
 			/* Fall through */
 		cond_branch:
@@ -508,20 +501,20 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
 				break;
 			}
 
-			switch (filter[i].code) {
-			case BPF_S_JMP_JGT_X:
-			case BPF_S_JMP_JGE_X:
-			case BPF_S_JMP_JEQ_X:
+			switch (code) {
+			case BPF_JMP | BPF_JGT | BPF_X:
+			case BPF_JMP | BPF_JGE | BPF_X:
+			case BPF_JMP | BPF_JEQ | BPF_X:
 				ctx->seen |= SEEN_XREG;
 				PPC_CMPLW(r_A, r_X);
 				break;
-			case BPF_S_JMP_JSET_X:
+			case BPF_JMP | BPF_JSET | BPF_X:
 				ctx->seen |= SEEN_XREG;
 				PPC_AND_DOT(r_scratch1, r_A, r_X);
 				break;
-			case BPF_S_JMP_JEQ_K:
-			case BPF_S_JMP_JGT_K:
-			case BPF_S_JMP_JGE_K:
+			case BPF_JMP | BPF_JEQ | BPF_K:
+			case BPF_JMP | BPF_JGT | BPF_K:
+			case BPF_JMP | BPF_JGE | BPF_K:
 				if (K < 32768)
 					PPC_CMPLWI(r_A, K);
 				else {
@@ -529,7 +522,7 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
 					PPC_CMPLW(r_A, r_scratch1);
 				}
 				break;
-			case BPF_S_JMP_JSET_K:
+			case BPF_JMP | BPF_JSET | BPF_K:
 				if (K < 32768)
 					/* PPC_ANDI is /only/ dot-form */
 					PPC_ANDI(r_scratch1, r_A, K);