[src/trunk]: src/sys/net Add BPF_MOD/BPF_XOR (untested, needs work)

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/d9ecffeab93a
branches:  trunk
changeset: 333859:d9ecffeab93a
user:      christos <christos%NetBSD.org@localhost>
date:      Wed Nov 19 19:34:43 2014 +0000

description:
Add BPF_MOD/BPF_XOR (untested, needs work)

diffstat:

 sys/net/bpfjit.c |  48 +++++++++++++++++++++++++++++++++---------------
 1 files changed, 33 insertions(+), 15 deletions(-)

diffs (142 lines):

diff -r c5ff3791c78a -r d9ecffeab93a sys/net/bpfjit.c
--- a/sys/net/bpfjit.c  Wed Nov 19 19:33:30 2014 +0000
+++ b/sys/net/bpfjit.c  Wed Nov 19 19:34:43 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: bpfjit.c,v 1.32 2014/07/26 11:23:46 alnsn Exp $        */
+/*     $NetBSD: bpfjit.c,v 1.33 2014/11/19 19:34:43 christos Exp $     */
 
 /*-
  * Copyright (c) 2011-2014 Alexander Nasonov.
@@ -31,9 +31,9 @@
 
 #include <sys/cdefs.h>
 #ifdef _KERNEL
-__KERNEL_RCSID(0, "$NetBSD: bpfjit.c,v 1.32 2014/07/26 11:23:46 alnsn Exp $");
+__KERNEL_RCSID(0, "$NetBSD: bpfjit.c,v 1.33 2014/11/19 19:34:43 christos Exp $");
 #else
-__RCSID("$NetBSD: bpfjit.c,v 1.32 2014/07/26 11:23:46 alnsn Exp $");
+__RCSID("$NetBSD: bpfjit.c,v 1.33 2014/11/19 19:34:43 christos Exp $");
 #endif
 
 #include <sys/types.h>
@@ -76,6 +76,11 @@
 #endif
 
 /*
+ * XXX: Until we support SLJIT_UMOD properly
+ */
+#undef BPFJIT_USE_UDIV
+
+/*
  * Arguments of generated bpfjit_func_t.
  * The first argument is reassigned upon entry
  * to a more frequently used buf argument.
@@ -1113,14 +1118,21 @@
 
        return (uint32_t)x / (uint32_t)y;
 }
+
+static sljit_uw
+modulus(sljit_uw x, sljit_uw y)
+{
+
+       return (uint32_t)x % (uint32_t)y;
+}
 #endif
 
 /*
- * Emit code for A = A / div.
+ * Emit code for A = A / div or A = A % div
  * divt,divw are either SLJIT_IMM,pc->k or BJ_XREG,0.
  */
 static int
-emit_division(struct sljit_compiler *compiler, int divt, sljit_sw divw)
+emit_moddiv(bool div, struct sljit_compiler *compiler, int divt, sljit_sw divw)
 {
        int status;
 
@@ -1161,7 +1173,8 @@
 #else
        status = sljit_emit_ijump(compiler,
            SLJIT_CALL2,
-           SLJIT_IMM, SLJIT_FUNC_OFFSET(divide));
+           SLJIT_IMM, div ? SLJIT_FUNC_OFFSET(divide) :
+               SLJIT_FUNC_OFFSET(modulus));
 
 #if BJ_AREG != SLJIT_RETURN_REG
        status = sljit_emit_op1(compiler,
@@ -1560,6 +1573,7 @@
        case BPF_SUB: return SLJIT_SUB;
        case BPF_MUL: return SLJIT_MUL|SLJIT_INT_OP;
        case BPF_OR:  return SLJIT_OR;
+       case BPF_XOR: return SLJIT_XOR;
        case BPF_AND: return SLJIT_AND;
        case BPF_LSH: return SLJIT_SHL;
        case BPF_RSH: return SLJIT_LSHR|SLJIT_INT_OP;
@@ -1648,7 +1662,7 @@
        size_t i;
        int status;
        int branching, negate;
-       unsigned int rval, mode, src;
+       unsigned int rval, mode, src, op;
        uint32_t jt, jf;
 
        bool unconditional_ret;
@@ -1884,7 +1898,8 @@
                                continue;
                        }
 
-                       if (BPF_OP(pc->code) != BPF_DIV) {
+                       op = BPF_OP(pc->code);
+                       if (op != BPF_DIV && op != BPF_MOD) {
                                status = sljit_emit_op2(compiler,
                                    bpf_alu_to_sljit_op(pc),
                                    BJ_AREG, 0,
@@ -1896,7 +1911,7 @@
                                continue;
                        }
 
-                       /* BPF_DIV */
+                       /* BPF_DIV/BPF_MOD */
 
                        src = BPF_SRC(pc->code);
                        if (src != BPF_X && src != BPF_K)
@@ -1923,13 +1938,15 @@
                        }
 
                        if (src == BPF_X) {
-                               status = emit_division(compiler, BJ_XREG, 0);
+                               status = emit_moddiv(op == BPF_DIV,
+                                   compiler, BJ_XREG, 0);
                                if (status != SLJIT_SUCCESS)
                                        goto fail;
                        } else if (pc->k != 0) {
-                               if (pc->k & (pc->k - 1)) {
-                                   status = emit_division(compiler,
-                                       SLJIT_IMM, (uint32_t)pc->k);
+                               /* XXX: We can do better here for MOD */
+                               if ((pc->k & (pc->k - 1)) || op == BPF_MOD) {
+                                   status = emit_moddiv(op == BPF_DIV,
+                                       compiler, SLJIT_IMM, (uint32_t)pc->k);
                                } else {
                                    status = emit_pow2_division(compiler,
                                        (uint32_t)pc->k);
@@ -1941,7 +1958,8 @@
                        continue;
 
                case BPF_JMP:
-                       if (BPF_OP(pc->code) == BPF_JA) {
+                       op = BPF_OP(pc->code);
+                       if (op == BPF_JA) {
                                jt = jf = pc->k;
                        } else {
                                jt = pc->jt;
@@ -1953,7 +1971,7 @@
                        jtf = insn_dat[i].u.jdata.jtf;
 
                        if (branching) {
-                               if (BPF_OP(pc->code) != BPF_JSET) {
+                               if (op != BPF_JSET) {
                                        jump = sljit_emit_cmp(compiler,
                                            bpf_jmp_to_sljit_cond(pc, negate),
                                            BJ_AREG, 0,