s390: bpf: eliminate zero extension code-gen

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 5e7c630..e636728 100644 (file)
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -299,9 +299,11 @@ static inline void reg_set_seen(struct bpf_jit *jit, u32 b1)
 
 #define EMIT_ZERO(b1)                                          \
 ({                                                             \
-       /* llgfr %dst,%dst (zero extend to 64 bit) */           \
-       EMIT4(0xb9160000, b1, b1);                              \
-       REG_SET_SEEN(b1);                                       \
+       if (!fp->aux->verifier_zext) {                          \
+               /* llgfr %dst,%dst (zero extend to 64 bit) */   \
+               EMIT4(0xb9160000, b1, b1);                      \
+               REG_SET_SEEN(b1);                               \
+       }                                                       \
 })
 
 /*
@@ -520,6 +522,8 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i
        case BPF_ALU | BPF_MOV | BPF_X: /* dst = (u32) src */
                /* llgfr %dst,%src */
                EMIT4(0xb9160000, dst_reg, src_reg);
+               if (insn_is_zext(&insn[1]))
+                       insn_count = 2;
                break;
        case BPF_ALU64 | BPF_MOV | BPF_X: /* dst = src */
                /* lgr %dst,%src */
@@ -528,6 +532,8 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i
        case BPF_ALU | BPF_MOV | BPF_K: /* dst = (u32) imm */
                /* llilf %dst,imm */
                EMIT6_IMM(0xc00f0000, dst_reg, imm);
+               if (insn_is_zext(&insn[1]))
+                       insn_count = 2;
                break;
        case BPF_ALU64 | BPF_MOV | BPF_K: /* dst = imm */
                /* lgfi %dst,imm */
@@ -639,6 +645,8 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i
                EMIT4(0xb9970000, REG_W0, src_reg);
                /* llgfr %dst,%rc */
                EMIT4(0xb9160000, dst_reg, rc_reg);
+               if (insn_is_zext(&insn[1]))
+                       insn_count = 2;
                break;
        }
        case BPF_ALU64 | BPF_DIV | BPF_X: /* dst = dst / src */
@@ -676,6 +684,8 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i
                              EMIT_CONST_U32(imm));
                /* llgfr %dst,%rc */
                EMIT4(0xb9160000, dst_reg, rc_reg);
+               if (insn_is_zext(&insn[1]))
+                       insn_count = 2;
                break;
        }
        case BPF_ALU64 | BPF_DIV | BPF_K: /* dst = dst / imm */
@@ -864,10 +874,13 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i
                case 16: /* dst = (u16) cpu_to_be16(dst) */
                        /* llghr %dst,%dst */
                        EMIT4(0xb9850000, dst_reg, dst_reg);
+                       if (insn_is_zext(&insn[1]))
+                               insn_count = 2;
                        break;
                case 32: /* dst = (u32) cpu_to_be32(dst) */
-                       /* llgfr %dst,%dst */
-                       EMIT4(0xb9160000, dst_reg, dst_reg);
+                       if (!fp->aux->verifier_zext)
+                               /* llgfr %dst,%dst */
+                               EMIT4(0xb9160000, dst_reg, dst_reg);
                        break;
                case 64: /* dst = (u64) cpu_to_be64(dst) */
                        break;
@@ -882,12 +895,15 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i
                        EMIT4_DISP(0x88000000, dst_reg, REG_0, 16);
                        /* llghr %dst,%dst */
                        EMIT4(0xb9850000, dst_reg, dst_reg);
+                       if (insn_is_zext(&insn[1]))
+                               insn_count = 2;
                        break;
                case 32: /* dst = (u32) cpu_to_le32(dst) */
                        /* lrvr %dst,%dst */
                        EMIT4(0xb91f0000, dst_reg, dst_reg);
-                       /* llgfr %dst,%dst */
-                       EMIT4(0xb9160000, dst_reg, dst_reg);
+                       if (!fp->aux->verifier_zext)
+                               /* llgfr %dst,%dst */
+                               EMIT4(0xb9160000, dst_reg, dst_reg);
                        break;
                case 64: /* dst = (u64) cpu_to_le64(dst) */
                        /* lrvgr %dst,%dst */
@@ -968,16 +984,22 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i
                /* llgc %dst,0(off,%src) */
                EMIT6_DISP_LH(0xe3000000, 0x0090, dst_reg, src_reg, REG_0, off);
                jit->seen |= SEEN_MEM;
+               if (insn_is_zext(&insn[1]))
+                       insn_count = 2;
                break;
        case BPF_LDX | BPF_MEM | BPF_H: /* dst = *(u16 *)(ul) (src + off) */
                /* llgh %dst,0(off,%src) */
                EMIT6_DISP_LH(0xe3000000, 0x0091, dst_reg, src_reg, REG_0, off);
                jit->seen |= SEEN_MEM;
+               if (insn_is_zext(&insn[1]))
+                       insn_count = 2;
                break;
        case BPF_LDX | BPF_MEM | BPF_W: /* dst = *(u32 *)(ul) (src + off) */
                /* llgf %dst,off(%src) */
                jit->seen |= SEEN_MEM;
                EMIT6_DISP_LH(0xe3000000, 0x0016, dst_reg, src_reg, REG_0, off);
+               if (insn_is_zext(&insn[1]))
+                       insn_count = 2;
                break;
        case BPF_LDX | BPF_MEM | BPF_DW: /* dst = *(u64 *)(ul) (src + off) */
                /* lg %dst,0(off,%src) */
@@ -1282,6 +1304,11 @@ static int bpf_jit_prog(struct bpf_jit *jit, struct bpf_prog *fp)
        return 0;
 }
 
+bool bpf_jit_needs_zext(void)
+{
+       return true;
+}
+
 /*
  * Compile eBPF program "fp"
  */