nfp: bpf: fix ALU32 high bits clearance bug

Jiong Wang · borkmann · commit f036ebd9bfbe · 2019-02-23T00:07:47.000+01:00
NFP BPF JIT compiler is doing a couple of small optimizations when jitting ALU imm instructions, some of these optimizations could save code-gen, for example: A & -1 = A A | 0 = A A ^ 0 = A However, for ALU32, high 32-bit of the 64-bit register should still be cleared according to ISA semantics. Fixes: cd7df56 ("nfp: add BPF to NFP code translator") Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
diff --git a/drivers/net/ethernet/netronome/nfp/bpf/jit.c b/drivers/net/ethernet/netronome/nfp/bpf/jit.c
@@ -1291,15 +1291,10 @@ wrp_alu64_reg(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta,
 
 static int
 wrp_alu32_imm(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta,
-	      enum alu_op alu_op, bool skip)
+	      enum alu_op alu_op)
 {
 	const struct bpf_insn *insn = &meta->insn;
 
-	if (skip) {
-		meta->skip = true;
-		return 0;
-	}
-
 	wrp_alu_imm(nfp_prog, insn->dst_reg * 2, alu_op, insn->imm);
 	wrp_immed(nfp_prog, reg_both(insn->dst_reg * 2 + 1), 0);
 
@@ -2309,7 +2304,7 @@ static int xor_reg(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
 
 static int xor_imm(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
 {
-	return wrp_alu32_imm(nfp_prog, meta, ALU_OP_XOR, !meta->insn.imm);
+	return wrp_alu32_imm(nfp_prog, meta, ALU_OP_XOR);
 }
 
 static int and_reg(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
@@ -2319,7 +2314,7 @@ static int and_reg(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
 
 static int and_imm(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
 {
-	return wrp_alu32_imm(nfp_prog, meta, ALU_OP_AND, !~meta->insn.imm);
+	return wrp_alu32_imm(nfp_prog, meta, ALU_OP_AND);
 }
 
 static int or_reg(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
@@ -2329,7 +2324,7 @@ static int or_reg(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
 
 static int or_imm(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
 {
-	return wrp_alu32_imm(nfp_prog, meta, ALU_OP_OR, !meta->insn.imm);
+	return wrp_alu32_imm(nfp_prog, meta, ALU_OP_OR);
 }
 
 static int add_reg(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
@@ -2339,7 +2334,7 @@ static int add_reg(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
 
 static int add_imm(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
 {
-	return wrp_alu32_imm(nfp_prog, meta, ALU_OP_ADD, !meta->insn.imm);
+	return wrp_alu32_imm(nfp_prog, meta, ALU_OP_ADD);
 }
 
 static int sub_reg(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
@@ -2349,7 +2344,7 @@ static int sub_reg(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
 
 static int sub_imm(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
 {
-	return wrp_alu32_imm(nfp_prog, meta, ALU_OP_SUB, !meta->insn.imm);
+	return wrp_alu32_imm(nfp_prog, meta, ALU_OP_SUB);
 }
 
 static int mul_reg(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)

Original file line number	Diff line number	Diff line change
`@@ -1291,15 +1291,10 @@ wrp_alu64_reg(struct nfp_prog nfp_prog, struct nfp_insn_meta meta,`
`1291`	`1291`
`1292`	`1292`	`static int`
`1293`	`1293`	`wrp_alu32_imm(struct nfp_prog nfp_prog, struct nfp_insn_meta meta,`
`1294`		`- enum alu_op alu_op, bool skip)`
	`1294`	`+ enum alu_op alu_op)`
`1295`	`1295`	`{`
`1296`	`1296`	`const struct bpf_insn *insn = &meta->insn;`
`1297`	`1297`
`1298`		`- if (skip) {`
`1299`		`- meta->skip = true;`
`1300`		`- return 0;`
`1301`		`- }`
`1302`		`-`
`1303`	`1298`	`wrp_alu_imm(nfp_prog, insn->dst_reg * 2, alu_op, insn->imm);`
`1304`	`1299`	`wrp_immed(nfp_prog, reg_both(insn->dst_reg * 2 + 1), 0);`
`1305`	`1300`
`@@ -2309,7 +2304,7 @@ static int xor_reg(struct nfp_prog nfp_prog, struct nfp_insn_meta meta)`
`2309`	`2304`
`2310`	`2305`	`static int xor_imm(struct nfp_prog nfp_prog, struct nfp_insn_meta meta)`
`2311`	`2306`	`{`
`2312`		`- return wrp_alu32_imm(nfp_prog, meta, ALU_OP_XOR, !meta->insn.imm);`
	`2307`	`+ return wrp_alu32_imm(nfp_prog, meta, ALU_OP_XOR);`
`2313`	`2308`	`}`
`2314`	`2309`
`2315`	`2310`	`static int and_reg(struct nfp_prog nfp_prog, struct nfp_insn_meta meta)`
`@@ -2319,7 +2314,7 @@ static int and_reg(struct nfp_prog nfp_prog, struct nfp_insn_meta meta)`
`2319`	`2314`
`2320`	`2315`	`static int and_imm(struct nfp_prog nfp_prog, struct nfp_insn_meta meta)`
`2321`	`2316`	`{`
`2322`		`- return wrp_alu32_imm(nfp_prog, meta, ALU_OP_AND, !~meta->insn.imm);`
	`2317`	`+ return wrp_alu32_imm(nfp_prog, meta, ALU_OP_AND);`
`2323`	`2318`	`}`
`2324`	`2319`
`2325`	`2320`	`static int or_reg(struct nfp_prog nfp_prog, struct nfp_insn_meta meta)`
`@@ -2329,7 +2324,7 @@ static int or_reg(struct nfp_prog nfp_prog, struct nfp_insn_meta meta)`
`2329`	`2324`
`2330`	`2325`	`static int or_imm(struct nfp_prog nfp_prog, struct nfp_insn_meta meta)`
`2331`	`2326`	`{`
`2332`		`- return wrp_alu32_imm(nfp_prog, meta, ALU_OP_OR, !meta->insn.imm);`
	`2327`	`+ return wrp_alu32_imm(nfp_prog, meta, ALU_OP_OR);`
`2333`	`2328`	`}`
`2334`	`2329`
`2335`	`2330`	`static int add_reg(struct nfp_prog nfp_prog, struct nfp_insn_meta meta)`
`@@ -2339,7 +2334,7 @@ static int add_reg(struct nfp_prog nfp_prog, struct nfp_insn_meta meta)`
`2339`	`2334`
`2340`	`2335`	`static int add_imm(struct nfp_prog nfp_prog, struct nfp_insn_meta meta)`
`2341`	`2336`	`{`
`2342`		`- return wrp_alu32_imm(nfp_prog, meta, ALU_OP_ADD, !meta->insn.imm);`
	`2337`	`+ return wrp_alu32_imm(nfp_prog, meta, ALU_OP_ADD);`
`2343`	`2338`	`}`
`2344`	`2339`
`2345`	`2340`	`static int sub_reg(struct nfp_prog nfp_prog, struct nfp_insn_meta meta)`
`@@ -2349,7 +2344,7 @@ static int sub_reg(struct nfp_prog nfp_prog, struct nfp_insn_meta meta)`
`2349`	`2344`
`2350`	`2345`	`static int sub_imm(struct nfp_prog nfp_prog, struct nfp_insn_meta meta)`
`2351`	`2346`	`{`
`2352`		`- return wrp_alu32_imm(nfp_prog, meta, ALU_OP_SUB, !meta->insn.imm);`
	`2347`	`+ return wrp_alu32_imm(nfp_prog, meta, ALU_OP_SUB);`
`2353`	`2348`	`}`
`2354`	`2349`
`2355`	`2350`	`static int mul_reg(struct nfp_prog nfp_prog, struct nfp_insn_meta meta)`