cpu: add eBPF cpu description

This patch adds a CPU description for the Linux kernel eBPF virtual
machine, plus supporting code for disassembler and assembler.

cpu/ChangeLog:

2019-05-23  Jose E. Marchesi  <jose.marchesi@oracle.com>

	* bpf.cpu: New file.
	* bpf.opc: Likewise.

1 files changed, 191 insertions, 0 deletions

diff --git a/cpu/bpf.opc b/cpu/bpf.opc
new file mode 100644
index 0000000..e70ee04
--- /dev/null
+++ b/cpu/bpf.opc
@@ -0,0 +1,191 @@
+/* EBPF opcode support.  -*- c -*-
+
+   Copyright (C) 2019 Free Software Foundation, Inc.
+
+   Contributed by Oracle, Inc.
+
+   This file is part of the GNU Binutils and of GDB.
+
+   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, write to the Free Software
+   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+   MA 02110-1301, USA.  */
+
+/*
+   Each section is delimited with start and end markers.
+
+   <arch>-opc.h additions use: "-- opc.h"
+   <arch>-opc.c additions use: "-- opc.c"
+   <arch>-asm.c additions use: "-- asm.c"
+   <arch>-dis.c additions use: "-- dis.c"
+   <arch>-ibd.h additions use: "-- ibd.h".  */
+
+/* -- opc.h */
+
+#undef CGEN_DIS_HASH_SIZE
+#define CGEN_DIS_HASH_SIZE 1
+
+#undef CGEN_DIS_HASH
+#define CGEN_DIS_HASH(buffer, value) 0
+
+/* Allows reason codes to be output when assembler errors occur.  */
+#define CGEN_VERBOSE_ASSEMBLER_ERRORS
+
+#define CGEN_VALIDATE_INSN_SUPPORTED
+extern int bpf_cgen_insn_supported (CGEN_CPU_DESC, const CGEN_INSN *);
+
+
+/* -- opc.c */
+
+/* -- asm.c */
+
+/* Parse a signed 64-bit immediate.  */
+
+static const char *
+parse_imm64 (CGEN_CPU_DESC cd,
+             const char **strp,
+             int opindex,
+             int64_t *valuep)
+{
+  bfd_vma value;
+  enum cgen_parse_operand_result result;
+  const char *errmsg;
+
+  errmsg = (* cd->parse_operand_fn)
+    (cd, CGEN_PARSE_OPERAND_INTEGER, strp, opindex, BFD_RELOC_NONE,
+     &result, &value);
+  if (!errmsg)
+    *valuep = value;
+
+  return errmsg;
+}
+
+/* Endianness size operands are integer immediates whose values can be
+   16, 32 or 64.  */
+
+static const char *
+parse_endsize (CGEN_CPU_DESC cd,
+               const char **strp,
+               int opindex,
+               unsigned long *valuep)
+{
+  const char *errmsg;
+
+  errmsg = cgen_parse_unsigned_integer (cd, strp, opindex, valuep);
+  if (errmsg)
+    return errmsg;
+
+  switch (*valuep)
+    {
+    case 16:
+    case 32:
+    case 64:
+      break;
+    default:
+      return _("expected 16, 32 or 64 in");
+    }
+
+  return NULL;
+}
+
+/* Special check to ensure that the right instruction variant is used
+   for the given endianness induced by the ISA selected in the CPU.
+   See bpf.cpu for a discussion on how eBPF is really two instruction
+   sets.  */
+
+int
+bpf_cgen_insn_supported (CGEN_CPU_DESC cd, const CGEN_INSN *insn)
+{
+  CGEN_BITSET isas = CGEN_INSN_BITSET_ATTR_VALUE (insn, CGEN_INSN_ISA);
+
+  return cgen_bitset_intersect_p (&isas, cd->isas);
+}
+
+
+/* -- dis.c */
+
+/* We need to customize the disassembler a bit:
+   - Use 8 bytes per line by default.
+*/
+
+#define CGEN_PRINT_INSN bpf_print_insn
+
+static int
+bpf_print_insn (CGEN_CPU_DESC cd, bfd_vma pc, disassemble_info *info)
+{
+  bfd_byte buf[CGEN_MAX_INSN_SIZE];
+  int buflen;
+  int status;
+
+  info->bytes_per_chunk = 1;
+  info->bytes_per_line = 8;
+
+  /* Attempt to read the base part of the insn.  */
+  buflen = cd->base_insn_bitsize / 8;
+  status = (*info->read_memory_func) (pc, buf, buflen, info);
+
+  /* Try again with the minimum part, if min < base.  */
+  if (status != 0 && (cd->min_insn_bitsize < cd->base_insn_bitsize))
+    {
+      buflen = cd->min_insn_bitsize / 8;
+      status = (*info->read_memory_func) (pc, buf, buflen, info);
+    }
+
+  if (status != 0)
+    {
+      (*info->memory_error_func) (status, pc, info);
+      return -1;
+    }
+
+  return print_insn (cd, pc, info, buf, buflen);
+}
+
+/* Signed immediates should be printed in hexadecimal.  */
+
+static void
+print_immediate (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
+                 void *dis_info,
+                 int64_t value,
+                 unsigned int attrs ATTRIBUTE_UNUSED,
+                 bfd_vma pc ATTRIBUTE_UNUSED,
+                 int length ATTRIBUTE_UNUSED)
+{
+  disassemble_info *info = (disassemble_info *) dis_info;
+
+  if (value <= 9)
+    (*info->fprintf_func) (info->stream, "%" PRId64, value);
+  else
+    (*info->fprintf_func) (info->stream, "%#" PRIx64, value);
+
+  /* This is to avoid -Wunused-function for print_normal.  */
+  if (0)
+    print_normal (cd, dis_info, value, attrs, pc, length);
+}
+
+/* Endianness bit sizes should be printed in decimal.  */
+
+static void
+print_endsize (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
+               void *dis_info,
+               unsigned long value,
+               unsigned int attrs ATTRIBUTE_UNUSED,
+               bfd_vma pc ATTRIBUTE_UNUSED,
+               int length ATTRIBUTE_UNUSED)
+{
+  disassemble_info *info = (disassemble_info *) dis_info;
+  (*info->fprintf_func) (info->stream, "%lu", value);
+}
+
+
+/* -- */
+