1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Common functionality for HPPA32 and HPPA64 BPF JIT compilers 4 * 5 * Copyright (c) 2023 Helge Deller <deller@gmx.de> 6 * 7 */ 8 9 #include <linux/bpf.h> 10 #include <linux/filter.h> 11 #include "bpf_jit.h" 12 13 /* Number of iterations to try until offsets converge. */ 14 #define NR_JIT_ITERATIONS 35 15 16 static int build_body(struct hppa_jit_context *ctx, bool extra_pass, int *offset) 17 { 18 const struct bpf_prog *prog = ctx->prog; 19 int i; 20 21 ctx->reg_seen_collect = true; 22 for (i = 0; i < prog->len; i++) { 23 const struct bpf_insn *insn = &prog->insnsi[i]; 24 int ret; 25 26 ret = bpf_jit_emit_insn(insn, ctx, extra_pass); 27 /* BPF_LD | BPF_IMM | BPF_DW: skip the next instruction. */ 28 if (ret > 0) 29 i++; 30 if (offset) 31 offset[i] = ctx->ninsns; 32 if (ret < 0) 33 return ret; 34 } 35 ctx->reg_seen_collect = false; 36 return 0; 37 } 38 39 bool bpf_jit_needs_zext(void) 40 { 41 return true; 42 } 43 44 struct bpf_prog *bpf_int_jit_compile(struct bpf_verifier_env *env, struct bpf_prog *prog) 45 { 46 unsigned int prog_size = 0, extable_size = 0; 47 bool extra_pass = false; 48 int pass = 0, prev_ninsns = 0, prologue_len, i; 49 struct hppa_jit_data *jit_data; 50 struct hppa_jit_context *ctx; 51 52 if (!prog->jit_requested) 53 return prog; 54 55 jit_data = prog->aux->jit_data; 56 if (!jit_data) { 57 jit_data = kzalloc_obj(*jit_data); 58 if (!jit_data) 59 return prog; 60 prog->aux->jit_data = jit_data; 61 } 62 63 ctx = &jit_data->ctx; 64 65 if (ctx->offset) { 66 extra_pass = true; 67 prog_size = sizeof(*ctx->insns) * ctx->ninsns; 68 goto skip_init_ctx; 69 } 70 71 ctx->prog = prog; 72 ctx->offset = kzalloc_objs(int, prog->len); 73 if (!ctx->offset) 74 goto out_err; 75 for (i = 0; i < prog->len; i++) { 76 prev_ninsns += 20; 77 ctx->offset[i] = prev_ninsns; 78 } 79 80 for (i = 0; i < NR_JIT_ITERATIONS; i++) { 81 pass++; 82 ctx->ninsns = 0; 83 if (build_body(ctx, extra_pass, ctx->offset)) 84 goto out_err; 85 ctx->body_len = ctx->ninsns; 86 bpf_jit_build_prologue(ctx); 87 ctx->prologue_len = ctx->ninsns - ctx->body_len; 88 ctx->epilogue_offset = ctx->ninsns; 89 bpf_jit_build_epilogue(ctx); 90 91 if (ctx->ninsns == prev_ninsns) { 92 if (jit_data->header) 93 break; 94 /* obtain the actual image size */ 95 extable_size = prog->aux->num_exentries * 96 sizeof(struct exception_table_entry); 97 prog_size = sizeof(*ctx->insns) * ctx->ninsns; 98 99 jit_data->header = 100 bpf_jit_binary_alloc(prog_size + extable_size, 101 &jit_data->image, 102 sizeof(long), 103 bpf_fill_ill_insns); 104 if (!jit_data->header) 105 goto out_err; 106 107 ctx->insns = (u32 *)jit_data->image; 108 /* 109 * Now, when the image is allocated, the image can 110 * potentially shrink more (auipc/jalr -> jal). 111 */ 112 } 113 prev_ninsns = ctx->ninsns; 114 } 115 116 if (i == NR_JIT_ITERATIONS) { 117 pr_err("bpf-jit: image did not converge in <%d passes!\n", i); 118 if (jit_data->header) 119 bpf_jit_binary_free(jit_data->header); 120 goto out_err; 121 } 122 123 if (extable_size) 124 prog->aux->extable = (void *)ctx->insns + prog_size; 125 126 skip_init_ctx: 127 pass++; 128 ctx->ninsns = 0; 129 130 bpf_jit_build_prologue(ctx); 131 if (build_body(ctx, extra_pass, NULL)) { 132 bpf_jit_binary_free(jit_data->header); 133 goto out_err; 134 } 135 bpf_jit_build_epilogue(ctx); 136 137 if (HPPA_JIT_DEBUG || bpf_jit_enable > 1) { 138 if (HPPA_JIT_DUMP) 139 bpf_jit_dump(prog->len, prog_size, pass, ctx->insns); 140 if (HPPA_JIT_REBOOT) 141 { extern int machine_restart(char *); machine_restart(""); } 142 } 143 144 if (!prog->is_func || extra_pass) { 145 if (bpf_jit_binary_lock_ro(jit_data->header)) { 146 bpf_jit_binary_free(jit_data->header); 147 goto out_err; 148 } 149 bpf_flush_icache(jit_data->header, ctx->insns + ctx->ninsns); 150 } 151 152 prog->bpf_func = (void *)ctx->insns; 153 prog->jited = 1; 154 prog->jited_len = prog_size; 155 156 if (!prog->is_func || extra_pass) { 157 prologue_len = ctx->epilogue_offset - ctx->body_len; 158 for (i = 0; i < prog->len; i++) 159 ctx->offset[i] += prologue_len; 160 bpf_prog_fill_jited_linfo(prog, ctx->offset); 161 out_offset: 162 kfree(ctx->offset); 163 kfree(jit_data); 164 prog->aux->jit_data = NULL; 165 } 166 167 if (HPPA_JIT_REBOOT) 168 { extern int machine_restart(char *); machine_restart(""); } 169 170 return prog; 171 172 out_err: 173 if (extra_pass) { 174 prog->bpf_func = NULL; 175 prog->jited = 0; 176 prog->jited_len = 0; 177 } 178 goto out_offset; 179 } 180 181 u64 hppa_div64(u64 div, u64 divisor) 182 { 183 div = div64_u64(div, divisor); 184 return div; 185 } 186 187 u64 hppa_div64_rem(u64 div, u64 divisor) 188 { 189 u64 rem; 190 div64_u64_rem(div, divisor, &rem); 191 return rem; 192 } 193