sim/bpf: desCGENization of the BPF simulator

The BPF port in binutils has been rewritten (commit
d218e7fedc74d67837d2134120917f4ac877454c) in order to not be longer
based on CGEN.  Please see that commit log for more information.

This patch updates the BPF simulator accordingly.  The new
implementation is much simpler and it is based on the new BPF opcodes.

Tested with target bpf-unknown-none with both 64-bit little-endian
host and 32-bit little-endian host.

Note that I have not tested in a big-endian host yet.  I will do so
once this lands upstream so I can use the GCC compiler farm.

1 files changed, 0 insertions, 228 deletions

diff --git a/sim/bpf/sim-if.c b/sim/bpf/sim-if.c
deleted file mode 100644
index 1a3452f..0000000
--- a/sim/bpf/sim-if.c
+++ /dev/null
@@ -1,228 +0,0 @@
-/* Main simulator entry points specific to the eBPF.
-   Copyright (C) 2020-2023 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/callback.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_extra (sd, 0, sizeof (struct bpf_sim_cpu)) != 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_FILE (sd), 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 *env)
-{
-  SIM_CPU *current_cpu = STATE_CPU (sd, 0);
-  host_callback *cb = STATE_CALLBACK (sd);
-  bfd_vma 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);
-    }
-
-  if (STATE_PROG_ENVP (sd) != env)
-    {
-      freeargv (STATE_PROG_ENVP (sd));
-      STATE_PROG_ENVP (sd) = dupargv (env);
-    }
-
-  cb->argv = STATE_PROG_ARGV (sd);
-  cb->envp = STATE_PROG_ENVP (sd);
-
-  return SIM_RC_OK;
-}