1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * bpf_jit64.h: BPF JIT compiler for PPC64 4 * 5 * Copyright 2016 Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> 6 * IBM Corporation 7 */ 8 #ifndef _BPF_JIT64_H 9 #define _BPF_JIT64_H 10 11 #include "bpf_jit.h" 12 13 /* 14 * Stack layout: 15 * Ensure the top half (upto local_tmp_var) stays consistent 16 * with our redzone usage. 17 * 18 * [ prev sp ] <------------- 19 * [ nv gpr save area ] 6*8 | 20 * [ tail_call_cnt ] 8 | 21 * [ local_tmp_var ] 8 | 22 * fp (r31) --> [ ebpf stack space ] upto 512 | 23 * [ frame header ] 32/112 | 24 * sp (r1) ---> [ stack pointer ] -------------- 25 */ 26 27 /* for gpr non volatile registers BPG_REG_6 to 10 */ 28 #define BPF_PPC_STACK_SAVE (6*8) 29 /* for bpf JIT code internal usage */ 30 #define BPF_PPC_STACK_LOCALS 16 31 /* stack frame excluding BPF stack, ensure this is quadword aligned */ 32 #define BPF_PPC_STACKFRAME (STACK_FRAME_MIN_SIZE + \ 33 BPF_PPC_STACK_LOCALS + BPF_PPC_STACK_SAVE) 34 35 #ifndef __ASSEMBLY__ 36 37 /* BPF register usage */ 38 #define TMP_REG_1 (MAX_BPF_JIT_REG + 0) 39 #define TMP_REG_2 (MAX_BPF_JIT_REG + 1) 40 41 /* BPF to ppc register mappings */ 42 static const int b2p[] = { 43 /* function return value */ 44 [BPF_REG_0] = 8, 45 /* function arguments */ 46 [BPF_REG_1] = 3, 47 [BPF_REG_2] = 4, 48 [BPF_REG_3] = 5, 49 [BPF_REG_4] = 6, 50 [BPF_REG_5] = 7, 51 /* non volatile registers */ 52 [BPF_REG_6] = 27, 53 [BPF_REG_7] = 28, 54 [BPF_REG_8] = 29, 55 [BPF_REG_9] = 30, 56 /* frame pointer aka BPF_REG_10 */ 57 [BPF_REG_FP] = 31, 58 /* eBPF jit internal registers */ 59 [BPF_REG_AX] = 2, 60 [TMP_REG_1] = 9, 61 [TMP_REG_2] = 10 62 }; 63 64 /* PPC NVR range -- update this if we ever use NVRs below r27 */ 65 #define BPF_PPC_NVR_MIN 27 66 67 /* 68 * WARNING: These can use TMP_REG_2 if the offset is not at word boundary, 69 * so ensure that it isn't in use already. 70 */ 71 #define PPC_BPF_LL(r, base, i) do { \ 72 if ((i) % 4) { \ 73 PPC_LI(b2p[TMP_REG_2], (i)); \ 74 PPC_LDX(r, base, b2p[TMP_REG_2]); \ 75 } else \ 76 PPC_LD(r, base, i); \ 77 } while(0) 78 #define PPC_BPF_STL(r, base, i) do { \ 79 if ((i) % 4) { \ 80 PPC_LI(b2p[TMP_REG_2], (i)); \ 81 PPC_STDX(r, base, b2p[TMP_REG_2]); \ 82 } else \ 83 PPC_STD(r, base, i); \ 84 } while(0) 85 #define PPC_BPF_STLU(r, base, i) do { PPC_STDU(r, base, i); } while(0) 86 87 #define SEEN_FUNC 0x1000 /* might call external helpers */ 88 #define SEEN_STACK 0x2000 /* uses BPF stack */ 89 #define SEEN_TAILCALL 0x4000 /* uses tail calls */ 90 91 struct codegen_context { 92 /* 93 * This is used to track register usage as well 94 * as calls to external helpers. 95 * - register usage is tracked with corresponding 96 * bits (r3-r10 and r27-r31) 97 * - rest of the bits can be used to track other 98 * things -- for now, we use bits 16 to 23 99 * encoded in SEEN_* macros above 100 */ 101 unsigned int seen; 102 unsigned int idx; 103 unsigned int stack_size; 104 }; 105 106 #endif /* !__ASSEMBLY__ */ 107 108 #endif 109