ARM: 7259/3: net: JIT compiler for packet filters

Based of Matt Evans's PPC64 implementation.

The compiler generates ARM instructions but interworking is
supported for Thumb2 kernels.

Supports both little and big endian. Unaligned loads are emitted
for ARMv6+. Not all the BPF opcodes that deal with ancillary data
are supported. The scratch memory of the filter lives on the stack.
Hardware integer division is used if it is available.

Enabled in the same way as for x86-64 and PPC64:

	echo 1 > /proc/sys/net/core/bpf_jit_enable

A value greater than 1 enables opcode output.
Signed-off-by: Mircea Gherzan <mgherzan@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Kconfig

@@ -34,6 +34,7 @@ config ARM
 	select GENERIC_IRQ_SHOW
 	select CPU_PM if (SUSPEND || CPU_IDLE)
 	select GENERIC_PCI_IOMAP
+	select HAVE_BPF_JIT
 	help
 	  The ARM series is a line of low-power-consumption RISC chip designs
 	  licensed by ARM Ltd and targeted at embedded applications and

arch/arm/Makefile

@@ -253,6 +253,7 @@ core-$(CONFIG_VFP)		+= arch/arm/vfp/
 
 # If we have a machine-specific directory, then include it in the build.
 core-y				+= arch/arm/kernel/ arch/arm/mm/ arch/arm/common/
+core-y				+= arch/arm/net/
 core-y				+= $(machdirs) $(platdirs)
 
 drivers-$(CONFIG_OPROFILE)      += arch/arm/oprofile/

arch/arm/net/Makefile

+# ARM-specific networking code
+
+obj-$(CONFIG_BPF_JIT) += bpf_jit_32.o

arch/arm/net/bpf_jit_32.h

+/*
+ * Just-In-Time compiler for BPF filters on 32bit ARM
+ *
+ * Copyright (c) 2011 Mircea Gherzan <mgherzan@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; version 2 of the License.
+ */
+
+#ifndef PFILTER_OPCODES_ARM_H
+#define PFILTER_OPCODES_ARM_H
+
+#define ARM_R0	0
+#define ARM_R1	1
+#define ARM_R2	2
+#define ARM_R3	3
+#define ARM_R4	4
+#define ARM_R5	5
+#define ARM_R6	6
+#define ARM_R7	7
+#define ARM_R8	8
+#define ARM_R9	9
+#define ARM_R10	10
+#define ARM_FP	11
+#define ARM_IP	12
+#define ARM_SP	13
+#define ARM_LR	14
+#define ARM_PC	15
+
+#define ARM_COND_EQ		0x0
+#define ARM_COND_NE		0x1
+#define ARM_COND_CS		0x2
+#define ARM_COND_HS		ARM_COND_CS
+#define ARM_COND_CC		0x3
+#define ARM_COND_LO		ARM_COND_CC
+#define ARM_COND_MI		0x4
+#define ARM_COND_PL		0x5
+#define ARM_COND_VS		0x6
+#define ARM_COND_VC		0x7
+#define ARM_COND_HI		0x8
+#define ARM_COND_LS		0x9
+#define ARM_COND_GE		0xa
+#define ARM_COND_LT		0xb
+#define ARM_COND_GT		0xc
+#define ARM_COND_LE		0xd
+#define ARM_COND_AL		0xe
+
+/* register shift types */
+#define SRTYPE_LSL		0
+#define SRTYPE_LSR		1
+#define SRTYPE_ASR		2
+#define SRTYPE_ROR		3
+
+#define ARM_INST_ADD_R		0x00800000
+#define ARM_INST_ADD_I		0x02800000
+
+#define ARM_INST_AND_R		0x00000000
+#define ARM_INST_AND_I		0x02000000
+
+#define ARM_INST_BIC_R		0x01c00000
+#define ARM_INST_BIC_I		0x03c00000
+
+#define ARM_INST_B		0x0a000000
+#define ARM_INST_BX		0x012FFF10
+#define ARM_INST_BLX_R		0x012fff30
+
+#define ARM_INST_CMP_R		0x01500000
+#define ARM_INST_CMP_I		0x03500000
+
+#define ARM_INST_LDRB_I		0x05d00000
+#define ARM_INST_LDRB_R		0x07d00000
+#define ARM_INST_LDRH_I		0x01d000b0
+#define ARM_INST_LDR_I		0x05900000
+
+#define ARM_INST_LDM		0x08900000
+
+#define ARM_INST_LSL_I		0x01a00000
+#define ARM_INST_LSL_R		0x01a00010
+
+#define ARM_INST_LSR_I		0x01a00020
+#define ARM_INST_LSR_R		0x01a00030
+
+#define ARM_INST_MOV_R		0x01a00000
+#define ARM_INST_MOV_I		0x03a00000
+#define ARM_INST_MOVW		0x03000000
+#define ARM_INST_MOVT		0x03400000
+
+#define ARM_INST_MUL		0x00000090
+
+#define ARM_INST_POP		0x08bd0000
+#define ARM_INST_PUSH		0x092d0000
+
+#define ARM_INST_ORR_R		0x01800000
+#define ARM_INST_ORR_I		0x03800000
+
+#define ARM_INST_REV		0x06bf0f30
+#define ARM_INST_REV16		0x06bf0fb0
+
+#define ARM_INST_RSB_I		0x02600000
+
+#define ARM_INST_SUB_R		0x00400000
+#define ARM_INST_SUB_I		0x02400000
+
+#define ARM_INST_STR_I		0x05800000
+
+#define ARM_INST_TST_R		0x01100000
+#define ARM_INST_TST_I		0x03100000
+
+#define ARM_INST_UDIV		0x0730f010
+
+#define ARM_INST_UMULL		0x00800090
+
+/* register */
+#define _AL3_R(op, rd, rn, rm)	((op ## _R) | (rd) << 12 | (rn) << 16 | (rm))
+/* immediate */
+#define _AL3_I(op, rd, rn, imm)	((op ## _I) | (rd) << 12 | (rn) << 16 | (imm))
+
+#define ARM_ADD_R(rd, rn, rm)	_AL3_R(ARM_INST_ADD, rd, rn, rm)
+#define ARM_ADD_I(rd, rn, imm)	_AL3_I(ARM_INST_ADD, rd, rn, imm)
+
+#define ARM_AND_R(rd, rn, rm)	_AL3_R(ARM_INST_AND, rd, rn, rm)
+#define ARM_AND_I(rd, rn, imm)	_AL3_I(ARM_INST_AND, rd, rn, imm)
+
+#define ARM_BIC_R(rd, rn, rm)	_AL3_R(ARM_INST_BIC, rd, rn, rm)
+#define ARM_BIC_I(rd, rn, imm)	_AL3_I(ARM_INST_BIC, rd, rn, imm)
+
+#define ARM_B(imm24)		(ARM_INST_B | ((imm24) & 0xffffff))
+#define ARM_BX(rm)		(ARM_INST_BX | (rm))
+#define ARM_BLX_R(rm)		(ARM_INST_BLX_R | (rm))
+
+#define ARM_CMP_R(rn, rm)	_AL3_R(ARM_INST_CMP, 0, rn, rm)
+#define ARM_CMP_I(rn, imm)	_AL3_I(ARM_INST_CMP, 0, rn, imm)
+
+#define ARM_LDR_I(rt, rn, off)	(ARM_INST_LDR_I | (rt) << 12 | (rn) << 16 \
+				 | (off))
+#define ARM_LDRB_I(rt, rn, off)	(ARM_INST_LDRB_I | (rt) << 12 | (rn) << 16 \
+				 | (off))
+#define ARM_LDRB_R(rt, rn, rm)	(ARM_INST_LDRB_R | (rt) << 12 | (rn) << 16 \
+				 | (rm))
+#define ARM_LDRH_I(rt, rn, off)	(ARM_INST_LDRH_I | (rt) << 12 | (rn) << 16 \
+				 | (((off) & 0xf0) << 4) | ((off) & 0xf))
+
+#define ARM_LDM(rn, regs)	(ARM_INST_LDM | (rn) << 16 | (regs))
+
+#define ARM_LSL_R(rd, rn, rm)	(_AL3_R(ARM_INST_LSL, rd, 0, rn) | (rm) << 8)
+#define ARM_LSL_I(rd, rn, imm)	(_AL3_I(ARM_INST_LSL, rd, 0, rn) | (imm) << 7)
+
+#define ARM_LSR_R(rd, rn, rm)	(_AL3_R(ARM_INST_LSR, rd, 0, rn) | (rm) << 8)
+#define ARM_LSR_I(rd, rn, imm)	(_AL3_I(ARM_INST_LSR, rd, 0, rn) | (imm) << 7)
+
+#define ARM_MOV_R(rd, rm)	_AL3_R(ARM_INST_MOV, rd, 0, rm)
+#define ARM_MOV_I(rd, imm)	_AL3_I(ARM_INST_MOV, rd, 0, imm)
+
+#define ARM_MOVW(rd, imm)	\
+	(ARM_INST_MOVW | ((imm) >> 12) << 16 | (rd) << 12 | ((imm) & 0x0fff))
+
+#define ARM_MOVT(rd, imm)	\
+	(ARM_INST_MOVT | ((imm) >> 12) << 16 | (rd) << 12 | ((imm) & 0x0fff))
+
+#define ARM_MUL(rd, rm, rn)	(ARM_INST_MUL | (rd) << 16 | (rm) << 8 | (rn))
+
+#define ARM_POP(regs)		(ARM_INST_POP | (regs))
+#define ARM_PUSH(regs)		(ARM_INST_PUSH | (regs))
+
+#define ARM_ORR_R(rd, rn, rm)	_AL3_R(ARM_INST_ORR, rd, rn, rm)
+#define ARM_ORR_I(rd, rn, imm)	_AL3_I(ARM_INST_ORR, rd, rn, imm)
+#define ARM_ORR_S(rd, rn, rm, type, rs)	\
+	(ARM_ORR_R(rd, rn, rm) | (type) << 5 | (rs) << 7)
+
+#define ARM_REV(rd, rm)		(ARM_INST_REV | (rd) << 12 | (rm))
+#define ARM_REV16(rd, rm)	(ARM_INST_REV16 | (rd) << 12 | (rm))
+
+#define ARM_RSB_I(rd, rn, imm)	_AL3_I(ARM_INST_RSB, rd, rn, imm)
+
+#define ARM_SUB_R(rd, rn, rm)	_AL3_R(ARM_INST_SUB, rd, rn, rm)
+#define ARM_SUB_I(rd, rn, imm)	_AL3_I(ARM_INST_SUB, rd, rn, imm)
+
+#define ARM_STR_I(rt, rn, off)	(ARM_INST_STR_I | (rt) << 12 | (rn) << 16 \
+				 | (off))
+
+#define ARM_TST_R(rn, rm)	_AL3_R(ARM_INST_TST, 0, rn, rm)
+#define ARM_TST_I(rn, imm)	_AL3_I(ARM_INST_TST, 0, rn, imm)
+
+#define ARM_UDIV(rd, rn, rm)	(ARM_INST_UDIV | (rd) << 16 | (rn) | (rm) << 8)
+
+#define ARM_UMULL(rd_lo, rd_hi, rn, rm)	(ARM_INST_UMULL | (rd_hi) << 16 \
+					 | (rd_lo) << 12 | (rm) << 8 | rn)
+
+#endif /* PFILTER_OPCODES_ARM_H */