Module Name: src
Committed By: alnsn
Date: Sun Jul 13 18:48:27 UTC 2014
Modified Files:
src/sys/net: bpfjit.c
Log Message:
Don't use BJ_TMP2REG for 32bit packet reads. Assign this register to (buf+X)
in BPF_LD+BPF_IND and save one instruction.
To generate a diff of this commit:
cvs rdiff -u -r1.26 -r1.27 src/sys/net/bpfjit.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/net/bpfjit.c
diff -u src/sys/net/bpfjit.c:1.26 src/sys/net/bpfjit.c:1.27
--- src/sys/net/bpfjit.c:1.26 Sat Jul 12 20:14:18 2014
+++ src/sys/net/bpfjit.c Sun Jul 13 18:48:27 2014
@@ -1,4 +1,4 @@
-/* $NetBSD: bpfjit.c,v 1.26 2014/07/12 20:14:18 alnsn Exp $ */
+/* $NetBSD: bpfjit.c,v 1.27 2014/07/13 18:48:27 alnsn Exp $ */
/*-
* Copyright (c) 2011-2014 Alexander Nasonov.
@@ -31,9 +31,9 @@
#include <sys/cdefs.h>
#ifdef _KERNEL
-__KERNEL_RCSID(0, "$NetBSD: bpfjit.c,v 1.26 2014/07/12 20:14:18 alnsn Exp $");
+__KERNEL_RCSID(0, "$NetBSD: bpfjit.c,v 1.27 2014/07/13 18:48:27 alnsn Exp $");
#else
-__RCSID("$NetBSD: bpfjit.c,v 1.26 2014/07/12 20:14:18 alnsn Exp $");
+__RCSID("$NetBSD: bpfjit.c,v 1.27 2014/07/13 18:48:27 alnsn Exp $");
#endif
#include <sys/types.h>
@@ -123,11 +123,12 @@ __RCSID("$NetBSD: bpfjit.c,v 1.26 2014/0
* Optimization hints.
*/
typedef unsigned int bpfjit_hint_t;
-#define BJ_HINT_PKT 0x01 /* packet read */
-#define BJ_HINT_LDW 0x02 /* 32-bit load */
-#define BJ_HINT_COP 0x04 /* BPF_COP or BPF_COPX instruction */
+#define BJ_HINT_ABS 0x01 /* packet read at absolute offset */
+#define BJ_HINT_IND 0x02 /* packet read at variable offset */
+#define BJ_HINT_COP 0x04 /* BPF_COP or BPF_COPX instruction */
#define BJ_HINT_XREG 0x08 /* BJ_XREG is needed */
#define BJ_HINT_LDX 0x10 /* BPF_LDX instruction */
+#define BJ_HINT_PKT (BJ_HINT_ABS|BJ_HINT_IND) /* packet read */
/*
* Datatype for Array Bounds Check Elimination (ABC) pass.
@@ -256,7 +257,7 @@ nscratches(bpfjit_hint_t hints)
rv = 3; /* xcall with three arguments */
#endif
- if (hints & (BJ_HINT_LDW|BJ_HINT_PKT))
+ if (hints & BJ_HINT_IND)
rv = 3; /* uses BJ_TMP2REG */
if (hints & BJ_HINT_COP)
@@ -354,44 +355,46 @@ append_jump(struct sljit_jump *jump, str
* Emit code for BPF_LD+BPF_B+BPF_ABS A <- P[k:1].
*/
static int
-emit_read8(struct sljit_compiler *compiler, uint32_t k)
+emit_read8(struct sljit_compiler *compiler, sljit_si src, uint32_t k)
{
return sljit_emit_op1(compiler,
SLJIT_MOV_UB,
BJ_AREG, 0,
- SLJIT_MEM1(BJ_BUF), k);
+ SLJIT_MEM1(src), k);
}
/*
* Emit code for BPF_LD+BPF_H+BPF_ABS A <- P[k:2].
*/
static int
-emit_read16(struct sljit_compiler *compiler, uint32_t k)
+emit_read16(struct sljit_compiler *compiler, sljit_si src, uint32_t k)
{
int status;
- /* tmp1 = buf[k]; */
+ BJ_ASSERT(k <= UINT32_MAX - 1);
+
+ /* A = buf[k]; */
status = sljit_emit_op1(compiler,
SLJIT_MOV_UB,
- BJ_TMP1REG, 0,
- SLJIT_MEM1(BJ_BUF), k);
+ BJ_AREG, 0,
+ SLJIT_MEM1(src), k);
if (status != SLJIT_SUCCESS)
return status;
- /* A = buf[k+1]; */
+ /* tmp1 = buf[k+1]; */
status = sljit_emit_op1(compiler,
SLJIT_MOV_UB,
- BJ_AREG, 0,
- SLJIT_MEM1(BJ_BUF), k+1);
+ BJ_TMP1REG, 0,
+ SLJIT_MEM1(src), k+1);
if (status != SLJIT_SUCCESS)
return status;
- /* tmp1 = tmp1 << 8; */
+ /* A = A << 8; */
status = sljit_emit_op2(compiler,
SLJIT_SHL,
- BJ_TMP1REG, 0,
- BJ_TMP1REG, 0,
+ BJ_AREG, 0,
+ BJ_AREG, 0,
SLJIT_IMM, 8);
if (status != SLJIT_SUCCESS)
return status;
@@ -409,40 +412,34 @@ emit_read16(struct sljit_compiler *compi
* Emit code for BPF_LD+BPF_W+BPF_ABS A <- P[k:4].
*/
static int
-emit_read32(struct sljit_compiler *compiler, uint32_t k)
+emit_read32(struct sljit_compiler *compiler, sljit_si src, uint32_t k)
{
int status;
- /* tmp1 = buf[k]; */
- status = sljit_emit_op1(compiler,
- SLJIT_MOV_UB,
- BJ_TMP1REG, 0,
- SLJIT_MEM1(BJ_BUF), k);
- if (status != SLJIT_SUCCESS)
- return status;
+ BJ_ASSERT(k <= UINT32_MAX - 3);
- /* tmp2 = buf[k+1]; */
+ /* A = buf[k]; */
status = sljit_emit_op1(compiler,
SLJIT_MOV_UB,
- BJ_TMP2REG, 0,
- SLJIT_MEM1(BJ_BUF), k+1);
+ BJ_AREG, 0,
+ SLJIT_MEM1(src), k);
if (status != SLJIT_SUCCESS)
return status;
- /* A = buf[k+3]; */
+ /* tmp1 = buf[k+1]; */
status = sljit_emit_op1(compiler,
SLJIT_MOV_UB,
- BJ_AREG, 0,
- SLJIT_MEM1(BJ_BUF), k+3);
+ BJ_TMP1REG, 0,
+ SLJIT_MEM1(src), k+1);
if (status != SLJIT_SUCCESS)
return status;
- /* tmp1 = tmp1 << 24; */
+ /* A = A << 8; */
status = sljit_emit_op2(compiler,
SLJIT_SHL,
- BJ_TMP1REG, 0,
- BJ_TMP1REG, 0,
- SLJIT_IMM, 24);
+ BJ_AREG, 0,
+ BJ_AREG, 0,
+ SLJIT_IMM, 8);
if (status != SLJIT_SUCCESS)
return status;
@@ -459,33 +456,41 @@ emit_read32(struct sljit_compiler *compi
status = sljit_emit_op1(compiler,
SLJIT_MOV_UB,
BJ_TMP1REG, 0,
- SLJIT_MEM1(BJ_BUF), k+2);
+ SLJIT_MEM1(src), k+2);
if (status != SLJIT_SUCCESS)
return status;
- /* tmp2 = tmp2 << 16; */
+ /* A = A << 8; */
status = sljit_emit_op2(compiler,
SLJIT_SHL,
- BJ_TMP2REG, 0,
- BJ_TMP2REG, 0,
- SLJIT_IMM, 16);
+ BJ_AREG, 0,
+ BJ_AREG, 0,
+ SLJIT_IMM, 8);
if (status != SLJIT_SUCCESS)
return status;
- /* A = A + tmp2; */
+ /* A = A + tmp1; */
status = sljit_emit_op2(compiler,
SLJIT_ADD,
BJ_AREG, 0,
BJ_AREG, 0,
- BJ_TMP2REG, 0);
+ BJ_TMP1REG, 0);
+ if (status != SLJIT_SUCCESS)
+ return status;
+
+ /* tmp1 = buf[k+3]; */
+ status = sljit_emit_op1(compiler,
+ SLJIT_MOV_UB,
+ BJ_TMP1REG, 0,
+ SLJIT_MEM1(src), k+3);
if (status != SLJIT_SUCCESS)
return status;
- /* tmp1 = tmp1 << 8; */
+ /* A = A << 8; */
status = sljit_emit_op2(compiler,
SLJIT_SHL,
- BJ_TMP1REG, 0,
- BJ_TMP1REG, 0,
+ BJ_AREG, 0,
+ BJ_AREG, 0,
SLJIT_IMM, 8);
if (status != SLJIT_SUCCESS)
return status;
@@ -770,6 +775,7 @@ emit_pkt_read(struct sljit_compiler *com
{
int status = SLJIT_ERR_ALLOC_FAILED;
uint32_t width;
+ sljit_si ld_reg;
struct sljit_jump *jump;
#ifdef _KERNEL
struct sljit_label *label;
@@ -789,6 +795,7 @@ emit_pkt_read(struct sljit_compiler *com
}
#endif
+ ld_reg = BJ_BUF;
width = read_width(pc);
if (BPF_MODE(pc->code) == BPF_IND) {
@@ -801,10 +808,11 @@ emit_pkt_read(struct sljit_compiler *com
if (status != SLJIT_SUCCESS)
return status;
- /* buf += X; */
+ /* ld_reg = buf + X; */
+ ld_reg = BJ_TMP2REG;
status = sljit_emit_op2(compiler,
SLJIT_ADD,
- BJ_BUF, 0,
+ ld_reg, 0,
BJ_BUF, 0,
BJ_XREG, 0);
if (status != SLJIT_SUCCESS)
@@ -823,30 +831,19 @@ emit_pkt_read(struct sljit_compiler *com
switch (width) {
case 4:
- status = emit_read32(compiler, k);
+ status = emit_read32(compiler, ld_reg, k);
break;
case 2:
- status = emit_read16(compiler, k);
+ status = emit_read16(compiler, ld_reg, k);
break;
case 1:
- status = emit_read8(compiler, k);
+ status = emit_read8(compiler, ld_reg, k);
break;
}
if (status != SLJIT_SUCCESS)
return status;
- if (BPF_MODE(pc->code) == BPF_IND) {
- /* buf -= X; */
- status = sljit_emit_op2(compiler,
- SLJIT_SUB,
- BJ_BUF, 0,
- BJ_BUF, 0,
- BJ_XREG, 0);
- if (status != SLJIT_SUCCESS)
- return status;
- }
-
#ifdef _KERNEL
over_mchain_jump = sljit_emit_jump(compiler, SLJIT_JUMP);
if (over_mchain_jump == NULL)
@@ -1260,16 +1257,11 @@ optimize_pass1(const bpf_ctx_t *bc, cons
continue;
case BPF_LD:
- if (BPF_MODE(insns[i].code) == BPF_IND ||
- BPF_MODE(insns[i].code) == BPF_ABS) {
- *hints |= BJ_HINT_PKT;
- }
-
- if (BPF_SIZE(insns[i].code) == BPF_W)
- *hints |= BJ_HINT_LDW;
+ if (BPF_MODE(insns[i].code) == BPF_ABS)
+ *hints |= BJ_HINT_ABS;
if (BPF_MODE(insns[i].code) == BPF_IND) {
- *hints |= BJ_HINT_XREG;
+ *hints |= BJ_HINT_IND | BJ_HINT_XREG;
*initmask |= invalid & BJ_INIT_XBIT;
}
