1 /* 2 * bpf_jit64.h: BPF JIT compiler for PPC64 3 * 4 * Copyright 2016 Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> 5 * IBM Corporation 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; version 2 10 * of the License. 11 */ 12 #ifndef _BPF_JIT64_H 13 #define _BPF_JIT64_H 14 15 #include "bpf_jit.h" 16 17 /* 18 * Stack layout: 19 * Ensure the top half (upto local_tmp_var) stays consistent 20 * with our redzone usage. 21 * 22 * [ prev sp ] <------------- 23 * [ nv gpr save area ] 8*8 | 24 * [ tail_call_cnt ] 8 | 25 * [ local_tmp_var ] 8 | 26 * fp (r31) --> [ ebpf stack space ] 512 | 27 * [ frame header ] 32/112 | 28 * sp (r1) ---> [ stack pointer ] -------------- 29 */ 30 31 /* for gpr non volatile registers BPG_REG_6 to 10, plus skb cache registers */ 32 #define BPF_PPC_STACK_SAVE (8*8) 33 /* for bpf JIT code internal usage */ 34 #define BPF_PPC_STACK_LOCALS 16 35 /* Ensure this is quadword aligned */ 36 #define BPF_PPC_STACKFRAME (STACK_FRAME_MIN_SIZE + MAX_BPF_STACK + \ 37 BPF_PPC_STACK_LOCALS + BPF_PPC_STACK_SAVE) 38 39 #ifndef __ASSEMBLY__ 40 41 /* BPF register usage */ 42 #define SKB_HLEN_REG (MAX_BPF_JIT_REG + 0) 43 #define SKB_DATA_REG (MAX_BPF_JIT_REG + 1) 44 #define TMP_REG_1 (MAX_BPF_JIT_REG + 2) 45 #define TMP_REG_2 (MAX_BPF_JIT_REG + 3) 46 47 /* BPF to ppc register mappings */ 48 static const int b2p[] = { 49 /* function return value */ 50 [BPF_REG_0] = 8, 51 /* function arguments */ 52 [BPF_REG_1] = 3, 53 [BPF_REG_2] = 4, 54 [BPF_REG_3] = 5, 55 [BPF_REG_4] = 6, 56 [BPF_REG_5] = 7, 57 /* non volatile registers */ 58 [BPF_REG_6] = 27, 59 [BPF_REG_7] = 28, 60 [BPF_REG_8] = 29, 61 [BPF_REG_9] = 30, 62 /* frame pointer aka BPF_REG_10 */ 63 [BPF_REG_FP] = 31, 64 /* eBPF jit internal registers */ 65 [BPF_REG_AX] = 2, 66 [SKB_HLEN_REG] = 25, 67 [SKB_DATA_REG] = 26, 68 [TMP_REG_1] = 9, 69 [TMP_REG_2] = 10 70 }; 71 72 /* PPC NVR range -- update this if we ever use NVRs below r24 */ 73 #define BPF_PPC_NVR_MIN 24 74 75 /* Assembly helpers */ 76 #define DECLARE_LOAD_FUNC(func) u64 func(u64 r3, u64 r4); \ 77 u64 func##_negative_offset(u64 r3, u64 r4); \ 78 u64 func##_positive_offset(u64 r3, u64 r4); 79 80 DECLARE_LOAD_FUNC(sk_load_word); 81 DECLARE_LOAD_FUNC(sk_load_half); 82 DECLARE_LOAD_FUNC(sk_load_byte); 83 84 #define CHOOSE_LOAD_FUNC(imm, func) \ 85 (imm < 0 ? \ 86 (imm >= SKF_LL_OFF ? func##_negative_offset : func) : \ 87 func##_positive_offset) 88 89 #define SEEN_FUNC 0x1000 /* might call external helpers */ 90 #define SEEN_STACK 0x2000 /* uses BPF stack */ 91 #define SEEN_SKB 0x4000 /* uses sk_buff */ 92 #define SEEN_TAILCALL 0x8000 /* uses tail calls */ 93 94 struct codegen_context { 95 /* 96 * This is used to track register usage as well 97 * as calls to external helpers. 98 * - register usage is tracked with corresponding 99 * bits (r3-r10 and r25-r31) 100 * - rest of the bits can be used to track other 101 * things -- for now, we use bits 16 to 23 102 * encoded in SEEN_* macros above 103 */ 104 unsigned int seen; 105 unsigned int idx; 106 }; 107 108 #endif /* !__ASSEMBLY__ */ 109 110 #endif 111