From 4b8e28c79356265b2c111e044142fb6d6d2db44e Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Thu, 24 May 2018 11:22:14 -0700 Subject: [PATCH] xtensa: use property tables for correct disassembly xtensa disassembler does not use information from the .xt.prop sections to switch between code/data disassembly in text sections. This may result in incorrect disassembly when data is interpreted as code and disassembler loses synchronization with instruction stream. Use .xt.prop section information to correctly interpret code and data and synchronize with instruction stream. 2018-06-04 Max Filippov bfd/ * elf32-xtensa.c (xtensa_read_table_entries): Make global. (compute_fill_extra_space): Drop declaration. Rename function to xtensa_compute_fill_extra_space. (compute_ebb_actions, remove_dead_literal): Update references to compute_fill_extra_space. include/ * elf/xtensa.h (xtensa_read_table_entries) (xtensa_compute_fill_extra_space): New declarations. opcodes/ * xtensa-dis.c (bfd.h, elf/xtensa.h): New includes. (dis_private): Add new fields for property section tracking. (xtensa_coalesce_insn_tables, xtensa_find_table_entry) (xtensa_instruction_fits): New functions. (fetch_data): Bump minimal fetch size to 4. (print_insn_xtensa): Make struct dis_private static. Load and prepare property table on section change. Don't disassemble literals. Don't disassemble instructions that cross property table boundaries. --- bfd/ChangeLog | 8 ++ bfd/elf32-xtensa.c | 9 +- include/ChangeLog | 5 + include/elf/xtensa.h | 8 ++ opcodes/ChangeLog | 12 +++ opcodes/xtensa-dis.c | 216 ++++++++++++++++++++++++++++++++++++++----- 6 files changed, 231 insertions(+), 27 deletions(-) diff --git a/bfd/ChangeLog b/bfd/ChangeLog index f373b8bf4b..d776d0b195 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,11 @@ +2018-06-04 Max Filippov + + * elf32-xtensa.c (xtensa_read_table_entries): Make global. + (compute_fill_extra_space): Drop declaration. Rename function to + xtensa_compute_fill_extra_space. + (compute_ebb_actions, remove_dead_literal): Update references to + compute_fill_extra_space. + 2018-06-04 Volodymyr Arbatov * elf32-xtensa.c (elf32xtensa_separate_props): New global diff --git a/bfd/elf32-xtensa.c b/bfd/elf32-xtensa.c index db3c8f4baa..44c1074446 100644 --- a/bfd/elf32-xtensa.c +++ b/bfd/elf32-xtensa.c @@ -802,7 +802,7 @@ property_table_matches (const void *ap, const void *bp) section. Sets TABLE_P and returns the number of entries. On error, returns a negative value. */ -static int +int xtensa_read_table_entries (bfd *abfd, asection *section, property_table_entry **table_p, @@ -6730,7 +6730,6 @@ static bfd_boolean check_section_ebb_pcrels_fit static bfd_boolean check_section_ebb_reduces (const ebb_constraint *); static void text_action_add_proposed (text_action_list *, const ebb_constraint *, asection *); -static int compute_fill_extra_space (property_table_entry *); /* First pass: */ static bfd_boolean compute_removed_literals @@ -8136,7 +8135,7 @@ compute_ebb_actions (ebb_constraint *ebb_table) BFD_ASSERT (action->action == ta_fill); BFD_ASSERT (ebb->ends_unreachable->flags & XTENSA_PROP_UNREACHABLE); - extra_space = compute_fill_extra_space (ebb->ends_unreachable); + extra_space = xtensa_compute_fill_extra_space (ebb->ends_unreachable); br = action->removed_bytes + removed_bytes + extra_space; br = br & ((1 << ebb->sec->alignment_power ) - 1); @@ -8560,7 +8559,7 @@ text_action_add_proposed (text_action_list *l, int -compute_fill_extra_space (property_table_entry *entry) +xtensa_compute_fill_extra_space (property_table_entry *entry) { int fill_extra_space; @@ -8841,7 +8840,7 @@ remove_dead_literal (bfd *abfd, do not add fill. */ the_add_entry = elf_xtensa_find_property_entry (prop_table, ptblsize, entry_sec_offset); - fill_extra_space = compute_fill_extra_space (the_add_entry); + fill_extra_space = xtensa_compute_fill_extra_space (the_add_entry); fa = find_fill_action (&relax_info->action_list, sec, entry_sec_offset); removed_diff = compute_removed_action_diff (fa, sec, entry_sec_offset, diff --git a/include/ChangeLog b/include/ChangeLog index 76a312a0dd..7d32268941 100644 --- a/include/ChangeLog +++ b/include/ChangeLog @@ -1,3 +1,8 @@ +2018-06-04 Max Filippov + + * elf/xtensa.h (xtensa_read_table_entries) + (xtensa_compute_fill_extra_space): New declarations. + 2018-06-04 H.J. Lu * diagnostics.h (DIAGNOSTIC_IGNORE_STRINGOP_TRUNCATION): Always diff --git a/include/elf/xtensa.h b/include/elf/xtensa.h index 6278e21e57..632d9e0c8d 100644 --- a/include/elf/xtensa.h +++ b/include/elf/xtensa.h @@ -210,6 +210,14 @@ typedef struct property_table_entry_t #define XTENSA_PROP_INSN_ABSLIT 0x00020000 extern asection *xtensa_make_property_section (asection *, const char *); +extern int +xtensa_read_table_entries (bfd *abfd, + asection *section, + property_table_entry **table_p, + const char *sec_name, + bfd_boolean output_addr); +extern int +xtensa_compute_fill_extra_space (property_table_entry *entry); #ifdef __cplusplus } diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog index cb4c5ae657..e0e7382eba 100644 --- a/opcodes/ChangeLog +++ b/opcodes/ChangeLog @@ -1,3 +1,15 @@ +2018-06-04 Max Filippov + + * xtensa-dis.c (bfd.h, elf/xtensa.h): New includes. + (dis_private): Add new fields for property section tracking. + (xtensa_coalesce_insn_tables, xtensa_find_table_entry) + (xtensa_instruction_fits): New functions. + (fetch_data): Bump minimal fetch size to 4. + (print_insn_xtensa): Make struct dis_private static. + Load and prepare property table on section change. + Don't disassemble literals. Don't disassemble instructions that + cross property table boundaries. + 2018-06-01 H.J. Lu * configure: Regenerated. diff --git a/opcodes/xtensa-dis.c b/opcodes/xtensa-dis.c index d78f9d5f94..c11cf064ce 100644 --- a/opcodes/xtensa-dis.c +++ b/opcodes/xtensa-dis.c @@ -27,6 +27,8 @@ #include "xtensa-isa.h" #include "ansidecl.h" #include "libiberty.h" +#include "bfd.h" +#include "elf/xtensa.h" #include "disassemble.h" #include @@ -43,8 +45,119 @@ struct dis_private { bfd_byte *byte_buf; OPCODES_SIGJMP_BUF bailout; + /* Persistent fields, valid for last_section only. */ + asection *last_section; + property_table_entry *insn_table_entries; + int insn_table_entry_count; + /* Cached property table search position. */ + bfd_vma insn_table_cur_addr; + int insn_table_cur_idx; }; +static void +xtensa_coalesce_insn_tables (struct dis_private *priv) +{ + const int mask = ~(XTENSA_PROP_DATA | XTENSA_PROP_NO_TRANSFORM); + int count = priv->insn_table_entry_count; + int i, j; + + /* Loop over all entries, combining adjacent ones that differ only in + the flag bits XTENSA_PROP_DATA and XTENSA_PROP_NO_TRANSFORM. */ + + for (i = j = 0; j < count; ++i) + { + property_table_entry *entry = priv->insn_table_entries + i; + + *entry = priv->insn_table_entries[j]; + + for (++j; j < count; ++j) + { + property_table_entry *next = priv->insn_table_entries + j; + int fill = xtensa_compute_fill_extra_space (entry); + int size = entry->size + fill; + + if (entry->address + size == next->address) + { + int entry_flags = entry->flags & mask; + int next_flags = next->flags & mask; + + if (next_flags == entry_flags) + entry->size = next->address - entry->address + next->size; + else + break; + } + else + { + break; + } + } + } + priv->insn_table_entry_count = i; +} + +static property_table_entry * +xtensa_find_table_entry (bfd_vma memaddr, struct disassemble_info *info) +{ + struct dis_private *priv = (struct dis_private *) info->private_data; + int i; + + if (priv->insn_table_entries == NULL + || priv->insn_table_entry_count < 0) + return NULL; + + if (memaddr < priv->insn_table_cur_addr) + priv->insn_table_cur_idx = 0; + + for (i = priv->insn_table_cur_idx; i < priv->insn_table_entry_count; ++i) + { + property_table_entry *block = priv->insn_table_entries + i; + + if (block->size != 0) + { + if ((memaddr >= block->address + && memaddr < block->address + block->size) + || memaddr < block->address) + { + priv->insn_table_cur_addr = memaddr; + priv->insn_table_cur_idx = i; + return block; + } + } + } + return NULL; +} + +/* Check whether an instruction crosses an instruction block boundary + (according to property tables). + If it does, return 0 (doesn't fit), else return 1. */ + +static int +xtensa_instruction_fits (bfd_vma memaddr, int size, + property_table_entry *insn_block) +{ + unsigned max_size; + + /* If no property table info, assume it fits. */ + if (insn_block == NULL || size <= 0) + return 1; + + /* If too high, limit nextstop by the next insn address. */ + if (insn_block->address > memaddr) + { + /* memaddr is not in an instruction block, but is followed by one. */ + max_size = insn_block->address - memaddr; + } + else + { + /* memaddr is in an instruction block, go no further than the end. */ + max_size = insn_block->address + insn_block->size - memaddr; + } + + /* Crossing a boundary, doesn't "fit". */ + if ((unsigned)size > max_size) + return 0; + return 1; +} static int fetch_data (struct disassemble_info *info, bfd_vma memaddr) @@ -53,6 +166,8 @@ fetch_data (struct disassemble_info *info, bfd_vma memaddr) struct dis_private *priv = (struct dis_private *) info->private_data; int insn_size = xtensa_isa_maxlength (xtensa_default_isa); + insn_size = MAX (insn_size, 4); + /* Read the maximum instruction size, padding with zeros if we go past the end of the text section. This code will automatically adjust length when we hit the end of the buffer. */ @@ -140,11 +255,12 @@ print_insn_xtensa (bfd_vma memaddr, struct disassemble_info *info) xtensa_isa isa; xtensa_opcode opc; xtensa_format fmt; - struct dis_private priv; + static struct dis_private priv; static bfd_byte *byte_buf = NULL; static xtensa_insnbuf insn_buffer = NULL; static xtensa_insnbuf slot_buffer = NULL; - int first, first_slot, valid_insn; + int first, first_slot, valid_insn = 0; + property_table_entry *insn_block; if (!xtensa_default_isa) xtensa_default_isa = xtensa_isa_init (0, 0); @@ -175,6 +291,49 @@ print_insn_xtensa (bfd_vma memaddr, struct disassemble_info *info) priv.byte_buf = byte_buf; info->private_data = (void *) &priv; + + /* Prepare instruction tables. */ + + if (info->section != NULL) + { + asection *section = info->section; + + if (priv.last_section != section) + { + bfd *abfd = section->owner; + + if (priv.last_section != NULL) + { + /* Reset insn_table_entries. */ + priv.insn_table_entry_count = 0; + if (priv.insn_table_entries) + free (priv.insn_table_entries); + priv.insn_table_entries = NULL; + } + priv.last_section = section; + + /* Read insn_table_entries. */ + priv.insn_table_entry_count = + xtensa_read_table_entries (abfd, section, + &priv.insn_table_entries, + XTENSA_PROP_SEC_NAME, FALSE); + if (priv.insn_table_entry_count == 0) + { + if (priv.insn_table_entries) + free (priv.insn_table_entries); + priv.insn_table_entries = NULL; + /* Backwards compatibility support. */ + priv.insn_table_entry_count = + xtensa_read_table_entries (abfd, section, + &priv.insn_table_entries, + XTENSA_INSN_SEC_NAME, FALSE); + } + priv.insn_table_cur_idx = 0; + xtensa_coalesce_insn_tables (&priv); + } + /* Else nothing to do, same section as last time. */ + } + if (OPCODES_SIGSETJMP (priv.bailout) != 0) /* Error return. */ return -1; @@ -187,36 +346,49 @@ print_insn_xtensa (bfd_vma memaddr, struct disassemble_info *info) /* Fetch the maximum size instruction. */ bytes_fetched = fetch_data (info, memaddr); - /* Copy the bytes into the decode buffer. */ - memset (insn_buffer, 0, (xtensa_insnbuf_size (isa) * - sizeof (xtensa_insnbuf_word))); - xtensa_insnbuf_from_chars (isa, insn_buffer, priv.byte_buf, bytes_fetched); + insn_block = xtensa_find_table_entry (memaddr, info); - fmt = xtensa_format_decode (isa, insn_buffer); - if (fmt == XTENSA_UNDEFINED - || ((size = xtensa_format_length (isa, fmt)) > bytes_fetched)) - valid_insn = 0; - else + if (!insn_block || (insn_block->flags & XTENSA_PROP_INSN)) { - /* Make sure all the opcodes are valid. */ - valid_insn = 1; - nslots = xtensa_format_num_slots (isa, fmt); - for (n = 0; n < nslots; n++) + /* Copy the bytes into the decode buffer. */ + memset (insn_buffer, 0, (xtensa_insnbuf_size (isa) * + sizeof (xtensa_insnbuf_word))); + xtensa_insnbuf_from_chars (isa, insn_buffer, priv.byte_buf, + bytes_fetched); + + fmt = xtensa_format_decode (isa, insn_buffer); + if (fmt != XTENSA_UNDEFINED + && ((size = xtensa_format_length (isa, fmt)) <= bytes_fetched) + && xtensa_instruction_fits (memaddr, size, insn_block)) { - xtensa_format_get_slot (isa, fmt, n, insn_buffer, slot_buffer); - if (xtensa_opcode_decode (isa, fmt, n, slot_buffer) - == XTENSA_UNDEFINED) + /* Make sure all the opcodes are valid. */ + valid_insn = 1; + nslots = xtensa_format_num_slots (isa, fmt); + for (n = 0; n < nslots; n++) { - valid_insn = 0; - break; + xtensa_format_get_slot (isa, fmt, n, insn_buffer, slot_buffer); + if (xtensa_opcode_decode (isa, fmt, n, slot_buffer) + == XTENSA_UNDEFINED) + { + valid_insn = 0; + break; + } } } } if (!valid_insn) { - (*info->fprintf_func) (info->stream, ".byte %#02x", priv.byte_buf[0]); - return 1; + if (insn_block && (insn_block->flags & XTENSA_PROP_LITERAL) + && (memaddr & 3) == 0 && bytes_fetched >= 4) + { + return 4; + } + else + { + (*info->fprintf_func) (info->stream, ".byte %#02x", priv.byte_buf[0]); + return 1; + } } if (nslots > 1) -- 2.34.1