From 4167e8660e929fc8d20e3ec578713ecff6a9d1ec Mon Sep 17 00:00:00 2001 From: Luis Machado Date: Mon, 15 Jun 2020 15:50:55 -0300 Subject: Extend "x" and "print" commands to support memory tagging Extend the "x" and "print" commands to make use of memory tagging functionality, if supported by the architecture. The "print" command will point out any possible tag mismatches it finds when dealing with pointers, in case such a pointer is tagged. No additional modifiers are needed. Suppose we have a pointer "p" with value 0x1234 (logical tag 0x0) and that we have an allocation tag of 0x1 for that particular area of memory. This is the expected output: (gdb) p/x p Logical tag (0x0) does not match the allocation tag (0x1). $1 = 0x1234 The "x" command has a new 'm' modifier that will enable displaying of allocation tags alongside the data dump. It will display one allocation tag per line. AArch64 has a tag granule of 16 bytes, which means we can have one tag for every 16 bytes of memory. In this case, this is what the "x" command will display with the new 'm' modifier: (gdb) x/32bxm p 0x1234: 0x01 0x02 0x00 0x00 0x00 0x00 0x00 0x00 0x123c: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x1244: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x124c: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 (gdb) x/4gxm a 0x1234: 0x0000000000000201 0x0000000000000000 0x1244: 0x0000000000000000 0x0000000000000000 gdb/ChangeLog: YYYY-MM-DD Luis Machado * printcmd.c (decode_format): Handle the 'm' modifier. (do_examine): Display allocation tags when required/supported. (should_validate_memtags): New function. (print_command_1): Display memory tag mismatches. * valprint.h (struct format_data) : New field. --- gdb/printcmd.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++- gdb/valprint.h | 1 + 2 files changed, 83 insertions(+), 1 deletion(-) diff --git a/gdb/printcmd.c b/gdb/printcmd.c index c285bc9..ba86e25 100644 --- a/gdb/printcmd.c +++ b/gdb/printcmd.c @@ -54,6 +54,7 @@ #include "gdbsupport/byte-vector.h" #include "gdbsupport/gdb_optional.h" #include "gdbsupport/rsp-low.h" +#include "infrun.h" /* For memtag setting. */ /* Chain containing all defined mtag subcommands. */ @@ -210,6 +211,7 @@ decode_format (const char **string_ptr, int oformat, int osize) val.size = '?'; val.count = 1; val.raw = 0; + val.print_tags = false; if (*p == '-') { @@ -232,6 +234,11 @@ decode_format (const char **string_ptr, int oformat, int osize) val.raw = 1; p++; } + else if (*p == 'm') + { + val.print_tags = true; + p++; + } else if (*p >= 'a' && *p <= 'z') val.format = *p++; else @@ -1106,12 +1113,47 @@ do_examine (struct format_data fmt, struct gdbarch *gdbarch, CORE_ADDR addr) need_to_update_next_address = 1; } + /* Whether we need to print the memory tag information for the current + address range. */ + bool print_range_tag = true; + uint32_t gsize = gdbarch_memtag_granule_size (gdbarch); + /* Print as many objects as specified in COUNT, at most maxelts per line, with the address of the next one at the start of each line. */ while (count > 0) { QUIT; + + CORE_ADDR tag_laddr = 0, tag_haddr = 0; + + /* Print the memory tag information if requested. */ + if (fmt.print_tags && print_range_tag && memtag + && target_supports_memory_tagging ()) + { + tag_laddr = align_down (next_address, gsize); + tag_haddr = align_down (next_address + gsize, gsize); + + struct value *v_addr + = value_from_ulongest (builtin_type (gdbarch)->builtin_data_ptr, + tag_laddr); + + if (gdbarch_tagged_address_p (target_gdbarch (), v_addr)) + { + std::string atag = gdbarch_memtag_to_string (gdbarch, v_addr, + tag_allocation); + + if (!atag.empty ()) + { + printf_filtered (_("\n"), + atag.c_str (), + paddress (gdbarch, tag_laddr), + paddress (gdbarch, tag_haddr)); + } + } + print_range_tag = false; + } + if (format == 'i') fputs_filtered (pc_prefix (next_address), gdb_stdout); print_address (next_gdbarch, next_address, gdb_stdout); @@ -1142,6 +1184,11 @@ do_examine (struct format_data fmt, struct gdbarch *gdbarch, CORE_ADDR addr) /* Display any branch delay slots following the final insn. */ if (format == 'i' && count == 1) count += branch_delay_insns; + + /* Update the tag range based on the current address being + processed. */ + if (tag_haddr <= next_address) + print_range_tag = true; } printf_filtered ("\n"); } @@ -1214,6 +1261,26 @@ print_value (value *val, const value_print_options &opts) annotate_value_history_end (); } +/* Returns true if memory tags should be validated. False otherwise. */ + +static bool +should_validate_memtags (struct value *value) +{ + if (memtag && target_supports_memory_tagging () + && gdbarch_tagged_address_p (target_gdbarch (), value)) + { + gdb_assert (value && value_type (value)); + + enum type_code code = value_type (value)->code (); + + return (code == TYPE_CODE_PTR + || code == TYPE_CODE_REF + || code == TYPE_CODE_METHODPTR + || code == TYPE_CODE_MEMBERPTR); + } + return false; +} + /* Helper for parsing arguments for print_command_1. */ static struct value * @@ -1249,7 +1316,21 @@ print_command_1 (const char *args, int voidprint) if (voidprint || (val && value_type (val) && value_type (val)->code () != TYPE_CODE_VOID)) - print_value (val, print_opts); + { + /* If memory tagging validation is on, check if the tag is valid. */ + if (should_validate_memtags (val) + && gdbarch_memtag_mismatch_p (target_gdbarch (), val)) + { + std::string ltag = gdbarch_memtag_to_string (target_gdbarch (), + val, tag_logical); + std::string atag = gdbarch_memtag_to_string (target_gdbarch (), + val, tag_allocation); + printf_filtered (_("Logical tag (%s) does not match the " + "allocation tag (%s).\n"), + ltag.c_str (), atag.c_str ()); + } + print_value (val, print_opts); + } } /* See valprint.h. */ diff --git a/gdb/valprint.h b/gdb/valprint.h index 57bc033..37a7405 100644 --- a/gdb/valprint.h +++ b/gdb/valprint.h @@ -241,6 +241,7 @@ struct format_data int count; char format; char size; + bool print_tags; /* True if the value should be printed raw -- that is, bypassing python-based formatters. */ -- cgit v1.1