s390/bpf: Use lg(f)rl when long displacement cannot be used

[sfrench/cifs-2.6.git] / arch / s390 / net / bpf_jit_comp.c

diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 6b3f85e4c5b0c7984669775b4e777cdec00fe946..3398cd939496c004ad153104540125c9991a9cdd 100644 (file)
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -371,6 +371,24 @@ static bool is_valid_ldisp(int disp)
        return disp >= -524288 && disp <= 524287;
 }
 
+/*
+ * Return whether the next 32-bit literal pool entry can be referenced using
+ * Long-Displacement Facility
+ */
+static bool can_use_ldisp_for_lit32(struct bpf_jit *jit)
+{
+       return is_valid_ldisp(jit->lit32 - jit->base_ip);
+}
+
+/*
+ * Return whether the next 64-bit literal pool entry can be referenced using
+ * Long-Displacement Facility
+ */
+static bool can_use_ldisp_for_lit64(struct bpf_jit *jit)
+{
+       return is_valid_ldisp(jit->lit64 - jit->base_ip);
+}
+
 /*
  * Fill whole space with illegal instructions
  */
@@ -752,9 +770,18 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
                EMIT4_IMM(0xa7080000, REG_W0, 0);
                /* lr %w1,%dst */
                EMIT2(0x1800, REG_W1, dst_reg);
-               /* dl %w0,<d(imm)>(%l) */
-               EMIT6_DISP_LH(0xe3000000, 0x0097, REG_W0, REG_0, REG_L,
-                             EMIT_CONST_U32(imm));
+               if (!is_first_pass(jit) && can_use_ldisp_for_lit32(jit)) {
+                       /* dl %w0,<d(imm)>(%l) */
+                       EMIT6_DISP_LH(0xe3000000, 0x0097, REG_W0, REG_0, REG_L,
+                                     EMIT_CONST_U32(imm));
+               } else {
+                       /* lgfrl %dst,imm */
+                       EMIT6_PCREL_RILB(0xc40c0000, dst_reg,
+                                        _EMIT_CONST_U32(imm));
+                       jit->seen |= SEEN_LITERAL;
+                       /* dlr %w0,%dst */
+                       EMIT4(0xb9970000, REG_W0, dst_reg);
+               }
                /* llgfr %dst,%rc */
                EMIT4(0xb9160000, dst_reg, rc_reg);
                if (insn_is_zext(&insn[1]))
@@ -776,9 +803,18 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
                EMIT4_IMM(0xa7090000, REG_W0, 0);
                /* lgr %w1,%dst */
                EMIT4(0xb9040000, REG_W1, dst_reg);
-               /* dlg %w0,<d(imm)>(%l) */
-               EMIT6_DISP_LH(0xe3000000, 0x0087, REG_W0, REG_0, REG_L,
-                             EMIT_CONST_U64(imm));
+               if (!is_first_pass(jit) && can_use_ldisp_for_lit64(jit)) {
+                       /* dlg %w0,<d(imm)>(%l) */
+                       EMIT6_DISP_LH(0xe3000000, 0x0087, REG_W0, REG_0, REG_L,
+                                     EMIT_CONST_U64(imm));
+               } else {
+                       /* lgrl %dst,imm */
+                       EMIT6_PCREL_RILB(0xc4080000, dst_reg,
+                                        _EMIT_CONST_U64(imm));
+                       jit->seen |= SEEN_LITERAL;
+                       /* dlgr %w0,%dst */
+                       EMIT4(0xb9870000, REG_W0, dst_reg);
+               }
                /* lgr %dst,%rc */
                EMIT4(0xb9040000, dst_reg, rc_reg);
                break;
@@ -801,9 +837,19 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
                EMIT_ZERO(dst_reg);
                break;
        case BPF_ALU64 | BPF_AND | BPF_K: /* dst = dst & imm */
-               /* ng %dst,<d(imm)>(%l) */
-               EMIT6_DISP_LH(0xe3000000, 0x0080, dst_reg, REG_0, REG_L,
-                             EMIT_CONST_U64(imm));
+               if (!is_first_pass(jit) && can_use_ldisp_for_lit64(jit)) {
+                       /* ng %dst,<d(imm)>(%l) */
+                       EMIT6_DISP_LH(0xe3000000, 0x0080,
+                                     dst_reg, REG_0, REG_L,
+                                     EMIT_CONST_U64(imm));
+               } else {
+                       /* lgrl %w0,imm */
+                       EMIT6_PCREL_RILB(0xc4080000, REG_W0,
+                                        _EMIT_CONST_U64(imm));
+                       jit->seen |= SEEN_LITERAL;
+                       /* ngr %dst,%w0 */
+                       EMIT4(0xb9800000, dst_reg, REG_W0);
+               }
                break;
        /*
         * BPF_OR
@@ -823,9 +869,19 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
                EMIT_ZERO(dst_reg);
                break;
        case BPF_ALU64 | BPF_OR | BPF_K: /* dst = dst | imm */
-               /* og %dst,<d(imm)>(%l) */
-               EMIT6_DISP_LH(0xe3000000, 0x0081, dst_reg, REG_0, REG_L,
-                             EMIT_CONST_U64(imm));
+               if (!is_first_pass(jit) && can_use_ldisp_for_lit64(jit)) {
+                       /* og %dst,<d(imm)>(%l) */
+                       EMIT6_DISP_LH(0xe3000000, 0x0081,
+                                     dst_reg, REG_0, REG_L,
+                                     EMIT_CONST_U64(imm));
+               } else {
+                       /* lgrl %w0,imm */
+                       EMIT6_PCREL_RILB(0xc4080000, REG_W0,
+                                        _EMIT_CONST_U64(imm));
+                       jit->seen |= SEEN_LITERAL;
+                       /* ogr %dst,%w0 */
+                       EMIT4(0xb9810000, dst_reg, REG_W0);
+               }
                break;
        /*
         * BPF_XOR
@@ -847,9 +903,19 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
                EMIT_ZERO(dst_reg);
                break;
        case BPF_ALU64 | BPF_XOR | BPF_K: /* dst = dst ^ imm */
-               /* xg %dst,<d(imm)>(%l) */
-               EMIT6_DISP_LH(0xe3000000, 0x0082, dst_reg, REG_0, REG_L,
-                             EMIT_CONST_U64(imm));
+               if (!is_first_pass(jit) && can_use_ldisp_for_lit64(jit)) {
+                       /* xg %dst,<d(imm)>(%l) */
+                       EMIT6_DISP_LH(0xe3000000, 0x0082,
+                                     dst_reg, REG_0, REG_L,
+                                     EMIT_CONST_U64(imm));
+               } else {
+                       /* lgrl %w0,imm */
+                       EMIT6_PCREL_RILB(0xc4080000, REG_W0,
+                                        _EMIT_CONST_U64(imm));
+                       jit->seen |= SEEN_LITERAL;
+                       /* xgr %dst,%w0 */
+                       EMIT4(0xb9820000, dst_reg, REG_W0);
+               }
                break;
        /*
         * BPF_LSH