| /* Main simulator entry points specific to the eBPF. |
| Copyright (C) 2020-2021 Free Software Foundation, Inc. |
| |
| This file is part of GDB, the GNU debugger. |
| |
| 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; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| |
| /* This must come before any other includes. */ |
| #include "defs.h" |
| |
| #include <stdlib.h> |
| |
| #include "sim-main.h" |
| #include "sim-options.h" |
| #include "libiberty.h" |
| #include "bfd.h" |
| |
| /* Globals. */ |
| |
| /* String with the name of the section containing the BPF program to |
| run. */ |
| static char *bpf_program_section = NULL; |
| |
| extern uint64_t skb_data_offset; |
| |
| |
| /* Handle BPF-specific options. */ |
| |
| static SIM_RC bpf_option_handler (SIM_DESC, sim_cpu *, int, char *, int); |
| |
| typedef enum |
| { |
| OPTION_BPF_SET_PROGRAM = OPTION_START, |
| OPTION_BPF_LIST_PROGRAMS, |
| OPTION_BPF_VERIFY_PROGRAM, |
| OPTION_BPF_SKB_DATA_OFFSET, |
| } BPF_OPTION; |
| |
| static const OPTION bpf_options[] = |
| { |
| { {"bpf-set-program", required_argument, NULL, OPTION_BPF_SET_PROGRAM}, |
| '\0', "SECTION_NAME", "Set the entry point", |
| bpf_option_handler }, |
| { {"bpf-list-programs", no_argument, NULL, OPTION_BPF_LIST_PROGRAMS}, |
| '\0', "", "List loaded bpf programs", |
| bpf_option_handler }, |
| { {"bpf-verify-program", required_argument, NULL, OPTION_BPF_VERIFY_PROGRAM}, |
| '\0', "PROGRAM", "Run the verifier on the given BPF program", |
| bpf_option_handler }, |
| { {"skb-data-offset", required_argument, NULL, OPTION_BPF_SKB_DATA_OFFSET}, |
| '\0', "OFFSET", "Configure offsetof(struct sk_buff, data)", |
| bpf_option_handler }, |
| |
| { {NULL, no_argument, NULL, 0}, '\0', NULL, NULL, NULL, NULL } |
| }; |
| |
| static SIM_RC |
| bpf_option_handler (SIM_DESC sd, sim_cpu *cpu ATTRIBUTE_UNUSED, int opt, |
| char *arg, int is_command ATTRIBUTE_UNUSED) |
| { |
| switch ((BPF_OPTION) opt) |
| { |
| case OPTION_BPF_VERIFY_PROGRAM: |
| /* XXX call the verifier. */ |
| sim_io_printf (sd, "Verifying BPF program %s...\n", arg); |
| break; |
| |
| case OPTION_BPF_LIST_PROGRAMS: |
| /* XXX list programs. */ |
| sim_io_printf (sd, "BPF programs available:\n"); |
| break; |
| |
| case OPTION_BPF_SET_PROGRAM: |
| /* XXX: check that the section exists and tell the user about a |
| new start_address. */ |
| bpf_program_section = xstrdup (arg); |
| break; |
| |
| case OPTION_BPF_SKB_DATA_OFFSET: |
| skb_data_offset = strtoul (arg, NULL, 0); |
| break; |
| |
| default: |
| sim_io_eprintf (sd, "Unknown option `%s'\n", arg); |
| return SIM_RC_FAIL; |
| } |
| |
| return SIM_RC_OK; |
| } |
| |
| /* Like sim_state_free, but free the cpu buffers as well. */ |
| |
| static void |
| bpf_free_state (SIM_DESC sd) |
| { |
| if (STATE_MODULES (sd) != NULL) |
| sim_module_uninstall (sd); |
| |
| sim_cpu_free_all (sd); |
| sim_state_free (sd); |
| } |
| |
| extern const SIM_MACH * const bpf_sim_machs[]; |
| |
| /* Create an instance of the simulator. */ |
| |
| SIM_DESC |
| sim_open (SIM_OPEN_KIND kind, |
| host_callback *callback, |
| struct bfd *abfd, |
| char * const *argv) |
| { |
| /* XXX Analyze the program, and collect per-function information |
| like the kernel verifier does. The implementation of the CALL |
| instruction will need that information, to update %fp. */ |
| |
| SIM_DESC sd = sim_state_alloc (kind, callback); |
| |
| /* Set default options before parsing user options. */ |
| STATE_MACHS (sd) = bpf_sim_machs; |
| STATE_MODEL_NAME (sd) = "bpf-def"; |
| |
| if (sim_cpu_alloc_all (sd, 1) != SIM_RC_OK) |
| goto error; |
| |
| if (sim_pre_argv_init (sd, argv[0]) != SIM_RC_OK) |
| goto error; |
| |
| /* Add the BPF-specific option list to the simulator. */ |
| if (sim_add_option_table (sd, NULL, bpf_options) != SIM_RC_OK) |
| { |
| bpf_free_state (sd); |
| return 0; |
| } |
| |
| if (sim_parse_args (sd, argv) != SIM_RC_OK) |
| goto error; |
| |
| if (sim_analyze_program (sd, |
| (STATE_PROG_ARGV (sd) != NULL |
| ? *STATE_PROG_ARGV (sd) |
| : NULL), abfd) != SIM_RC_OK) |
| goto error; |
| |
| if (sim_config (sd) != SIM_RC_OK) |
| goto error; |
| |
| if (sim_post_argv_init (sd) != SIM_RC_OK) |
| goto error; |
| |
| /* ... */ |
| |
| /* Initialize the CPU descriptors and the disassemble in the cpu |
| descriptor table entries. */ |
| { |
| int i; |
| CGEN_CPU_DESC cd = bpf_cgen_cpu_open_1 (STATE_ARCHITECTURE (sd)->printable_name, |
| CGEN_ENDIAN_LITTLE); |
| |
| /* We have one cpu per installed program! MAX_NR_PROCESSORS is an |
| arbitrary upper limit. XXX where is it defined? */ |
| for (i = 0; i < MAX_NR_PROCESSORS; ++i) |
| { |
| SIM_CPU *cpu = STATE_CPU (sd, i); |
| |
| CPU_CPU_DESC (cpu) = cd; |
| CPU_DISASSEMBLER (cpu) = sim_cgen_disassemble_insn; |
| } |
| |
| bpf_cgen_init_dis (cd); |
| } |
| |
| /* XXX do eBPF sim specific initializations. */ |
| |
| return sd; |
| |
| error: |
| bpf_free_state (sd); |
| return NULL; |
| } |
| |
| |
| SIM_RC |
| sim_create_inferior (SIM_DESC sd, struct bfd *abfd, |
| char *const *argv, char *const *envp) |
| { |
| SIM_CPU *current_cpu = STATE_CPU (sd, 0); |
| SIM_ADDR addr; |
| |
| /* Determine the start address. |
| |
| XXX acknowledge bpf_program_section. If it is NULL, emit a |
| warning explaining that we are using the ELF file start address, |
| which often is not what is actually wanted. */ |
| if (abfd != NULL) |
| addr = bfd_get_start_address (abfd); |
| else |
| addr = 0; |
| |
| sim_pc_set (current_cpu, addr); |
| |
| if (STATE_PROG_ARGV (sd) != argv) |
| { |
| freeargv (STATE_PROG_ARGV (sd)); |
| STATE_PROG_ARGV (sd) = dupargv (argv); |
| } |
| |
| return SIM_RC_OK; |
| } |