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[src/trunk]: src/sys/net Don't use saved EREG registers because sljit 0.91 ca...
details: https://anonhg.NetBSD.org/src/rev/47d211086a8b
branches: trunk
changeset: 330986:47d211086a8b
user: alnsn <alnsn%NetBSD.org@localhost>
date: Sat Jul 26 11:23:46 2014 +0000
description:
Don't use saved EREG registers because sljit 0.91 can generate
bogus code on amd64. The A and X registers are saved on the stack.
The most recent version of sljit fixes bogus code generation but
it's not backward compatible with sljit 0.91.
diffstat:
sys/net/bpfjit.c | 131 ++++++++++++++++++++++++++++++++++++------------------
1 files changed, 88 insertions(+), 43 deletions(-)
diffs (truncated from 301 to 300 lines):
diff -r a841f1c4e6f7 -r 47d211086a8b sys/net/bpfjit.c
--- a/sys/net/bpfjit.c Sat Jul 26 09:18:53 2014 +0000
+++ b/sys/net/bpfjit.c Sat Jul 26 11:23:46 2014 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: bpfjit.c,v 1.31 2014/07/24 22:54:38 alnsn Exp $ */
+/* $NetBSD: bpfjit.c,v 1.32 2014/07/26 11:23:46 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 1.31 2014/07/24 22:54:38 alnsn Exp $");
+__KERNEL_RCSID(0, "$NetBSD: bpfjit.c,v 1.32 2014/07/26 11:23:46 alnsn Exp $");
#else
-__RCSID("$NetBSD: bpfjit.c,v 1.31 2014/07/24 22:54:38 alnsn Exp $");
+__RCSID("$NetBSD: bpfjit.c,v 1.32 2014/07/26 11:23:46 alnsn Exp $");
#endif
#include <sys/types.h>
@@ -89,12 +89,11 @@
#define BJ_BUF SLJIT_SAVED_REG1
//#define BJ_ARGS SLJIT_SAVED_REG2
#define BJ_BUFLEN SLJIT_SAVED_REG3
-#define BJ_XREG SLJIT_SAVED_EREG1
-#define BJ_ASAVE SLJIT_SAVED_EREG2
#define BJ_AREG SLJIT_SCRATCH_REG1
#define BJ_TMP1REG SLJIT_SCRATCH_REG2
#define BJ_TMP2REG SLJIT_SCRATCH_REG3
-#define BJ_TMP3REG SLJIT_TEMPORARY_EREG1
+#define BJ_XREG SLJIT_TEMPORARY_EREG1
+#define BJ_TMP3REG SLJIT_TEMPORARY_EREG2
#ifdef _KERNEL
#define MAX_MEMWORDS BPF_MAX_MEMWORDS
@@ -136,6 +135,7 @@
{
bpf_ctx_t *ctx;
uint32_t *extmem; /* pointer to external memory store */
+ uint32_t reg; /* saved A or X register */
#ifdef _KERNEL
int err; /* 3rd argument for m_xword/m_xhalf/m_xbyte function call */
#endif
@@ -259,8 +259,16 @@
if (hints & BJ_HINT_COP)
rv = 3; /* calls copfunc with three arguments */
+ if (hints & BJ_HINT_XREG)
+ rv = 4; /* uses BJ_XREG */
+
+#ifdef _KERNEL
+ if (hints & BJ_HINT_LDX)
+ rv = 5; /* uses BJ_TMP3REG */
+#endif
+
if (hints & BJ_HINT_COPX)
- rv = 4; /* uses BJ_TMP3REG */
+ rv = 5; /* uses BJ_TMP3REG */
return rv;
}
@@ -274,14 +282,6 @@
{
sljit_si rv = 3;
- if (hints & BJ_HINT_XREG)
- rv = 4; /* uses BJ_XREG */
-
-#ifdef _KERNEL
- if (hints & BJ_HINT_LDX)
- rv = 5; /* uses BJ_ASAVE */
-#endif
-
return rv;
}
@@ -528,21 +528,30 @@
* BPF_LDX+BPF_B+BPF_MSH X <- 4*(P[k:1]&0xf)
*/
static int
-emit_xcall(struct sljit_compiler *compiler, const struct bpf_insn *pc,
- int dst, struct sljit_jump ***ret0, size_t *ret0_size, size_t *ret0_maxsize,
+emit_xcall(struct sljit_compiler *compiler, bpfjit_hint_t hints,
+ const struct bpf_insn *pc, int dst, struct sljit_jump ***ret0,
+ size_t *ret0_size, size_t *ret0_maxsize,
uint32_t (*fn)(const struct mbuf *, uint32_t, int *))
{
+#if BJ_XREG == SLJIT_RETURN_REG || \
+ BJ_XREG == SLJIT_SCRATCH_REG1 || \
+ BJ_XREG == SLJIT_SCRATCH_REG2 || \
+ BJ_XREG == SLJIT_SCRATCH_REG3
+#error "Not supported assignment of registers."
+#endif
struct sljit_jump *jump;
+ sljit_si save_reg;
int status;
- BJ_ASSERT(dst != BJ_ASAVE);
+ save_reg = (BPF_CLASS(pc->code) == BPF_LDX) ? BJ_AREG : BJ_XREG;
- if (BPF_CLASS(pc->code) == BPF_LDX) {
- /* save A */
+ if (save_reg == BJ_AREG || (hints & BJ_HINT_XREG)) {
+ /* save A or X */
status = sljit_emit_op1(compiler,
- SLJIT_MOV,
- BJ_ASAVE, 0,
- BJ_AREG, 0);
+ SLJIT_MOV_UI, /* uint32_t destination */
+ SLJIT_MEM1(SLJIT_LOCALS_REG),
+ offsetof(struct bpfjit_stack, reg),
+ save_reg, 0);
if (status != SLJIT_SUCCESS)
return status;
}
@@ -634,12 +643,13 @@
if (!append_jump(jump, ret0, ret0_size, ret0_maxsize))
return SLJIT_ERR_ALLOC_FAILED;
- if (BPF_CLASS(pc->code) == BPF_LDX) {
- /* restore A */
+ if (save_reg == BJ_AREG || (hints & BJ_HINT_XREG)) {
+ /* restore A or X */
status = sljit_emit_op1(compiler,
- SLJIT_MOV,
- BJ_AREG, 0,
- BJ_ASAVE, 0);
+ SLJIT_MOV_UI, /* uint32_t source */
+ save_reg, 0,
+ SLJIT_MEM1(SLJIT_LOCALS_REG),
+ offsetof(struct bpfjit_stack, reg));
if (status != SLJIT_SUCCESS)
return status;
}
@@ -652,11 +662,15 @@
* Emit code for BPF_COP and BPF_COPX instructions.
*/
static int
-emit_cop(struct sljit_compiler *compiler,
+emit_cop(struct sljit_compiler *compiler, bpfjit_hint_t hints,
const bpf_ctx_t *bc, const struct bpf_insn *pc,
struct sljit_jump ***ret0, size_t *ret0_size, size_t *ret0_maxsize)
{
-#if BJ_TMP3REG == SLJIT_SCRATCH_REG1 || \
+#if BJ_XREG == SLJIT_RETURN_REG || \
+ BJ_XREG == SLJIT_SCRATCH_REG1 || \
+ BJ_XREG == SLJIT_SCRATCH_REG2 || \
+ BJ_XREG == SLJIT_SCRATCH_REG3 || \
+ BJ_TMP3REG == SLJIT_SCRATCH_REG1 || \
BJ_TMP3REG == SLJIT_SCRATCH_REG2 || \
BJ_TMP3REG == SLJIT_SCRATCH_REG3
#error "Not supported assignment of registers."
@@ -669,6 +683,17 @@
BJ_ASSERT(bc != NULL && bc->copfuncs != NULL);
+ if (hints & BJ_HINT_LDX) {
+ /* save X */
+ status = sljit_emit_op1(compiler,
+ SLJIT_MOV_UI, /* uint32_t destination */
+ SLJIT_MEM1(SLJIT_LOCALS_REG),
+ offsetof(struct bpfjit_stack, reg),
+ BJ_XREG, 0);
+ if (status != SLJIT_SUCCESS)
+ return status;
+ }
+
if (BPF_MISCOP(pc->code) == BPF_COP) {
call_reg = SLJIT_IMM;
call_off = SLJIT_FUNC_OFFSET(bc->copfuncs[pc->k]);
@@ -762,6 +787,17 @@
return status;
#endif
+ if (hints & BJ_HINT_LDX) {
+ /* restore X */
+ status = sljit_emit_op1(compiler,
+ SLJIT_MOV_UI, /* uint32_t source */
+ BJ_XREG, 0,
+ SLJIT_MEM1(SLJIT_LOCALS_REG),
+ offsetof(struct bpfjit_stack, reg));
+ if (status != SLJIT_SUCCESS)
+ return status;
+ }
+
return SLJIT_SUCCESS;
}
@@ -775,7 +811,7 @@
* BPF_LD+BPF_B+BPF_IND A <- P[X+k:1]
*/
static int
-emit_pkt_read(struct sljit_compiler *compiler,
+emit_pkt_read(struct sljit_compiler *compiler, bpfjit_hint_t hints,
const struct bpf_insn *pc, struct sljit_jump *to_mchain_jump,
struct sljit_jump ***ret0, size_t *ret0_size, size_t *ret0_maxsize)
{
@@ -875,15 +911,15 @@
switch (width) {
case 4:
- status = emit_xcall(compiler, pc, BJ_AREG,
+ status = emit_xcall(compiler, hints, pc, BJ_AREG,
ret0, ret0_size, ret0_maxsize, &m_xword);
break;
case 2:
- status = emit_xcall(compiler, pc, BJ_AREG,
+ status = emit_xcall(compiler, hints, pc, BJ_AREG,
ret0, ret0_size, ret0_maxsize, &m_xhalf);
break;
case 1:
- status = emit_xcall(compiler, pc, BJ_AREG,
+ status = emit_xcall(compiler, hints, pc, BJ_AREG,
ret0, ret0_size, ret0_maxsize, &m_xbyte);
break;
}
@@ -960,7 +996,7 @@
* Emit code for BPF_LDX+BPF_B+BPF_MSH X <- 4*(P[k:1]&0xf).
*/
static int
-emit_msh(struct sljit_compiler *compiler,
+emit_msh(struct sljit_compiler *compiler, bpfjit_hint_t hints,
const struct bpf_insn *pc, struct sljit_jump *to_mchain_jump,
struct sljit_jump ***ret0, size_t *ret0_size, size_t *ret0_maxsize)
{
@@ -1014,7 +1050,7 @@
return SLJIT_ERR_ALLOC_FAILED;
}
- status = emit_xcall(compiler, pc, BJ_TMP1REG,
+ status = emit_xcall(compiler, hints, pc, BJ_TMP1REG,
ret0, ret0_size, ret0_maxsize, &m_xbyte);
if (status != SLJIT_SUCCESS)
return status;
@@ -1088,6 +1124,13 @@
{
int status;
+#if BJ_XREG == SLJIT_RETURN_REG || \
+ BJ_XREG == SLJIT_SCRATCH_REG1 || \
+ BJ_XREG == SLJIT_SCRATCH_REG2 || \
+ BJ_AREG == SLJIT_SCRATCH_REG2
+#error "Not supported assignment of registers."
+#endif
+
#if BJ_AREG != SLJIT_SCRATCH_REG1
status = sljit_emit_op1(compiler,
SLJIT_MOV,
@@ -1588,9 +1631,9 @@
}
static bool
-generate_insn_code(struct sljit_compiler *compiler, const bpf_ctx_t *bc,
- const struct bpf_insn *insns, struct bpfjit_insn_data *insn_dat,
- size_t insn_count)
+generate_insn_code(struct sljit_compiler *compiler, bpfjit_hint_t hints,
+ const bpf_ctx_t *bc, const struct bpf_insn *insns,
+ struct bpfjit_insn_data *insn_dat, size_t insn_count)
{
/* a list of jumps to out-of-bound return from a generated function */
struct sljit_jump **ret0;
@@ -1736,7 +1779,7 @@
if (unconditional_ret)
continue;
- status = emit_pkt_read(compiler, pc,
+ status = emit_pkt_read(compiler, hints, pc,
to_mchain_jump, &ret0, &ret0_size, &ret0_maxsize);
if (status != SLJIT_SUCCESS)
goto fail;
@@ -1796,7 +1839,7 @@
if (unconditional_ret)
continue;
- status = emit_msh(compiler, pc,
+ status = emit_msh(compiler, hints, pc,
to_mchain_jump, &ret0, &ret0_size, &ret0_maxsize);
if (status != SLJIT_SUCCESS)
goto fail;
@@ -2004,7 +2047,7 @@
goto fail;
}
- status = emit_cop(compiler, bc, pc,
+ status = emit_cop(compiler, hints, bc, pc,
&ret0, &ret0_size, &ret0_maxsize);
if (status != SLJIT_SUCCESS)
goto fail;
@@ -2177,8 +2220,10 @@
if (status != SLJIT_SUCCESS)
goto fail;
- if (!generate_insn_code(compiler, bc, insns, insn_dat, insn_count))
+ if (!generate_insn_code(compiler, hints,
+ bc, insns, insn_dat, insn_count)) {
goto fail;
+ }
rv = sljit_generate_code(compiler);
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