From 156d0e290e969caba25f1851c52417c14d141b24 Mon Sep 17 00:00:00 2001 From: "Naveen N. Rao" Date: Wed, 22 Jun 2016 21:55:07 +0530 Subject: powerpc/ebpf/jit: Implement JIT compiler for extended BPF PPC64 eBPF JIT compiler. Enable with: echo 1 > /proc/sys/net/core/bpf_jit_enable or echo 2 > /proc/sys/net/core/bpf_jit_enable ... to see the generated JIT code. This can further be processed with tools/net/bpf_jit_disasm. With CONFIG_TEST_BPF=m and 'modprobe test_bpf': test_bpf: Summary: 305 PASSED, 0 FAILED, [297/297 JIT'ed] ... on both ppc64 BE and LE. The details of the approach are documented through various comments in the code. Acked-by: Alexei Starovoitov Signed-off-by: Naveen N. Rao Signed-off-by: Michael Ellerman --- arch/powerpc/net/bpf_jit64.h | 102 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 102 insertions(+) create mode 100644 arch/powerpc/net/bpf_jit64.h (limited to 'arch/powerpc/net/bpf_jit64.h') diff --git a/arch/powerpc/net/bpf_jit64.h b/arch/powerpc/net/bpf_jit64.h new file mode 100644 index 000000000000..5046d6f65c02 --- /dev/null +++ b/arch/powerpc/net/bpf_jit64.h @@ -0,0 +1,102 @@ +/* + * bpf_jit64.h: BPF JIT compiler for PPC64 + * + * Copyright 2016 Naveen N. Rao + * IBM Corporation + * + * 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 _BPF_JIT64_H +#define _BPF_JIT64_H + +#include "bpf_jit.h" + +/* + * Stack layout: + * + * [ prev sp ] <------------- + * [ nv gpr save area ] 8*8 | + * fp (r31) --> [ ebpf stack space ] 512 | + * [ local/tmp var space ] 16 | + * [ frame header ] 32/112 | + * sp (r1) ---> [ stack pointer ] -------------- + */ + +/* for bpf JIT code internal usage */ +#define BPF_PPC_STACK_LOCALS 16 +/* for gpr non volatile registers BPG_REG_6 to 10, plus skb cache registers */ +#define BPF_PPC_STACK_SAVE (8*8) +/* Ensure this is quadword aligned */ +#define BPF_PPC_STACKFRAME (STACK_FRAME_MIN_SIZE + BPF_PPC_STACK_LOCALS + \ + MAX_BPF_STACK + BPF_PPC_STACK_SAVE) + +#ifndef __ASSEMBLY__ + +/* BPF register usage */ +#define SKB_HLEN_REG (MAX_BPF_REG + 0) +#define SKB_DATA_REG (MAX_BPF_REG + 1) +#define TMP_REG_1 (MAX_BPF_REG + 2) +#define TMP_REG_2 (MAX_BPF_REG + 3) + +/* BPF to ppc register mappings */ +static const int b2p[] = { + /* function return value */ + [BPF_REG_0] = 8, + /* function arguments */ + [BPF_REG_1] = 3, + [BPF_REG_2] = 4, + [BPF_REG_3] = 5, + [BPF_REG_4] = 6, + [BPF_REG_5] = 7, + /* non volatile registers */ + [BPF_REG_6] = 27, + [BPF_REG_7] = 28, + [BPF_REG_8] = 29, + [BPF_REG_9] = 30, + /* frame pointer aka BPF_REG_10 */ + [BPF_REG_FP] = 31, + /* eBPF jit internal registers */ + [SKB_HLEN_REG] = 25, + [SKB_DATA_REG] = 26, + [TMP_REG_1] = 9, + [TMP_REG_2] = 10 +}; + +/* Assembly helpers */ +#define DECLARE_LOAD_FUNC(func) u64 func(u64 r3, u64 r4); \ + u64 func##_negative_offset(u64 r3, u64 r4); \ + u64 func##_positive_offset(u64 r3, u64 r4); + +DECLARE_LOAD_FUNC(sk_load_word); +DECLARE_LOAD_FUNC(sk_load_half); +DECLARE_LOAD_FUNC(sk_load_byte); + +#define CHOOSE_LOAD_FUNC(imm, func) \ + (imm < 0 ? \ + (imm >= SKF_LL_OFF ? func##_negative_offset : func) : \ + func##_positive_offset) + +#define SEEN_FUNC 0x1000 /* might call external helpers */ +#define SEEN_STACK 0x2000 /* uses BPF stack */ +#define SEEN_SKB 0x4000 /* uses sk_buff */ + +struct codegen_context { + /* + * This is used to track register usage as well + * as calls to external helpers. + * - register usage is tracked with corresponding + * bits (r3-r10 and r25-r31) + * - rest of the bits can be used to track other + * things -- for now, we use bits 16 to 23 + * encoded in SEEN_* macros above + */ + unsigned int seen; + unsigned int idx; +}; + +#endif /* !__ASSEMBLY__ */ + +#endif -- cgit v1.2.3