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net: filter: BPF 'JIT' compiler for PPC64

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An implementation of a code generator for BPF programs to speed up packet
filtering on PPC64, inspired by Eric Dumazet's x86-64 version.

Filter code is generated as an ABI-compliant function in module_alloc()'d mem
with stackframe & prologue/epilogue generated if required (simple filters don't
need anything more than an li/blr).  The filter's local variables, M[], live in
registers.  Supports all BPF opcodes, although "complicated" loads from negative
packet offsets (e.g. SKF_LL_OFF) are not yet supported.

There are a couple of further optimisations left for future work; many-pass
assembly with branch-reach reduction and a register allocator to push M[]
variables into volatile registers would improve the code quality further.

This currently supports big-endian 64-bit PowerPC only (but is fairly simple
to port to PPC32 or LE!).

Enabled in the same way as x86-64:

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

Or, enabled with extra debug output:

	echo 2 > /proc/sys/net/core/bpf_jit_enable

Signed-off-by: Matt Evans <matt@ozlabs.org>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Matt Evans
2011-07-20 15:51:00 +00:00
committed by David S. Miller
parent 3aeb7d2243
commit 0ca87f05ba
7 changed files with 1106 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

40
arch/powerpc/include/asm/ppc-opcode.h
View File

@@ -71,6 +71,42 @@
#define PPC_INST_ERATSX 0x7c000126
#define PPC_INST_ERATSX_DOT 0x7c000127
/* Misc instructions for BPF compiler */
#define PPC_INST_LD 0xe8000000
#define PPC_INST_LHZ 0xa0000000
#define PPC_INST_LWZ 0x80000000
#define PPC_INST_STD 0xf8000000
#define PPC_INST_STDU 0xf8000001
#define PPC_INST_MFLR 0x7c0802a6
#define PPC_INST_MTLR 0x7c0803a6
#define PPC_INST_CMPWI 0x2c000000
#define PPC_INST_CMPDI 0x2c200000
#define PPC_INST_CMPLW 0x7c000040
#define PPC_INST_CMPLWI 0x28000000
#define PPC_INST_ADDI 0x38000000
#define PPC_INST_ADDIS 0x3c000000
#define PPC_INST_ADD 0x7c000214
#define PPC_INST_SUB 0x7c000050
#define PPC_INST_BLR 0x4e800020
#define PPC_INST_BLRL 0x4e800021
#define PPC_INST_MULLW 0x7c0001d6
#define PPC_INST_MULHWU 0x7c000016
#define PPC_INST_MULLI 0x1c000000
#define PPC_INST_DIVWU 0x7c0003d6
#define PPC_INST_RLWINM 0x54000000
#define PPC_INST_RLDICR 0x78000004
#define PPC_INST_SLW 0x7c000030
#define PPC_INST_SRW 0x7c000430
#define PPC_INST_AND 0x7c000038
#define PPC_INST_ANDDOT 0x7c000039
#define PPC_INST_OR 0x7c000378
#define PPC_INST_ANDI 0x70000000
#define PPC_INST_ORI 0x60000000
#define PPC_INST_ORIS 0x64000000
#define PPC_INST_NEG 0x7c0000d0
#define PPC_INST_BRANCH 0x48000000
#define PPC_INST_BRANCH_COND 0x40800000
/* macros to insert fields into opcodes */
#define __PPC_RA(a) (((a) & 0x1f) << 16)
#define __PPC_RB(b) (((b) & 0x1f) << 11)
@@ -83,6 +119,10 @@
#define __PPC_T_TLB(t) (((t) & 0x3) << 21)
#define __PPC_WC(w) (((w) & 0x3) << 21)
#define __PPC_WS(w) (((w) & 0x1f) << 11)
#define __PPC_SH(s) __PPC_WS(s)
#define __PPC_MB(s) (((s) & 0x1f) << 6)
#define __PPC_ME(s) (((s) & 0x1f) << 1)
#define __PPC_BI(s) (((s) & 0x1f) << 16)
/*
* Only use the larx hint bit on 64bit CPUs. e500v1/v2 based CPUs will treat a