gdb: SPARC ADI support

The M7 processor supports an Application Data Integrity (ADI) feature
that detects invalid data accesses.  When software allocates data, it
chooses a 4-bit version number, sets the version in the upper 4 bits
of the 64-bit pointer to that data, and stores the 4-bit version in
every cacheline of the object.  Hardware saves the latter in spare
bits in the cache and memory hierarchy. On each load and store, the
processor compares the upper 4 VA (virtual address) bits to the
cacheline's version. If there is a mismatch, the processor generates a
version mismatch trap which can be either precise or disrupting.  The
trap is an error condition which the kernel delivers to the process as
a SIGSEGV signal.

The upper 4 bits of the VA represent a version and are not part of the
true address.  The processor clears these bits and sign extends bit 59
to generate the true address.

Note that 32-bit applications cannot use ADI.

This patch adds ADI support in gdb which allows the user to examine
current version tags and assign new version tags in the program.  It
also catches and reports precise or disrupting memory corruption
traps.

gdb/ChangeLog:
2017-08-07  Weimin Pan  <weimin.pan@oracle.com>

	* sparc64-tdep.h: (adi_normalize_address): New export.
	* sparc-nat.h: (open_adi_tag_fd): New export.
	* sparc64-linux-nat.c: (open_adi_tag_fd): New function.
	* sparc64-linux-tdep.c:
	(SEGV_ACCADI, SEGV_ADIDERR, SEGV_ADIPERR) New defines.
	(sparc64_linux_handle_segmentation_fault): New function.
	(sparc64_linux_init_abi): Register
	sparc64_linux_handle_segmentation_fault
	* sparc64-tdep.c: Include cli-utils.h,gdbcmd.h,auxv.h.
	(sparc64_addr_bits_remove): New function.
	(sparc64_init_abi): Register sparc64_addr_bits_remove.
	(MAX_PROC_NAME_SIZE): New macro.
	(AT_ADI_BLKSZ, AT_ADI_NBITS, AT_ADI_UEONADI) New defines.
	(sparc64adilist): New variable.
	(adi_proc_list): New variable.
	(find_adi_info): New function.
	(add_adi_info): New function.
	(get_adi_info_proc): New function.
	(get_adi_info): New function.
	(info_adi_command): New function.
	(read_maps_entry): New function.
	(adi_available): New function.
	(adi_normalize_address): New function.
	(adi_align_address): New function.
	(adi_convert_byte_count): New function.
	(adi_tag_fd): New function.
	(adi_is_addr_mapped): New function.
	(adi_read_versions): New function.
	(adi_write_versions): New function.
	(adi_print_versions): New function.
	(do_examine): New function.
	(do_assign): New function.
	(adi_examine_command): New function.
	(adi_assign_command): New function.
	(_initialize_sparc64_adi_tdep): New function.

gdb/doc/ChangeLog:
2017-08-07  Weimin Pan  <weimin.pan@oracle.com>

	* gdb.texinfo (Architectures): Add new Sparc64 section to document
	ADI support.
	* NEWS: Add "adi examine" and "adi assign" commands.

gdb/testsuite/ChangeLog:
2017-08-07  Weimin Pan  <weimin.pan@oracle.com>

	* gdb.arch/sparc64-adi.exp: New file.
	* gdb.arch/sparc64-adi.c: New file.

1 files changed, 69 insertions, 0 deletions

diff --git a/gdb/sparc64-linux-tdep.c b/gdb/sparc64-linux-tdep.c
index 814bc29ce29..2da978fbf80 100644
--- a/gdb/sparc64-linux-tdep.c
+++ b/gdb/sparc64-linux-tdep.c
@@ -33,6 +33,17 @@
 #include "xml-syscall.h"
 #include "linux-tdep.h"
 
+/* ADI specific si_code */
+#ifndef SEGV_ACCADI
+#define SEGV_ACCADI	3
+#endif
+#ifndef SEGV_ADIDERR
+#define SEGV_ADIDERR	4
+#endif
+#ifndef SEGV_ADIPERR
+#define SEGV_ADIPERR	5
+#endif
+
 /* The syscall's XML filename for sparc 64-bit.  */
 #define XML_SYSCALL_FILENAME_SPARC64 "syscalls/sparc64-linux.xml"
 
@@ -104,6 +115,62 @@ sparc64_linux_sigframe_init (const struct tramp_frame *self,
     }
   trad_frame_set_id (this_cache, frame_id_build (base, func));
 }
+
+/* sparc64 GNU/Linux implementation of the handle_segmentation_fault
+   gdbarch hook.
+   Displays information related to ADI memory corruptions.  */
+
+void
+sparc64_linux_handle_segmentation_fault (struct gdbarch *gdbarch,
+				      struct ui_out *uiout)
+{
+  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word != 64)
+    return;
+
+  CORE_ADDR addr = 0;
+  long si_code = 0;
+
+  TRY
+    {
+      /* Evaluate si_code to see if the segfault is ADI related.  */
+      si_code = parse_and_eval_long ("$_siginfo.si_code\n");
+
+      if (si_code >= SEGV_ACCADI && si_code <= SEGV_ADIPERR)
+        addr = parse_and_eval_long ("$_siginfo._sifields._sigfault.si_addr");
+    }
+  CATCH (exception, RETURN_MASK_ALL)
+    {
+      return;
+    }
+  END_CATCH
+
+  /* Print out ADI event based on sig_code value */
+  switch (si_code)
+    {
+    case SEGV_ACCADI:	/* adi not enabled */
+      uiout->text ("\n");
+      uiout->field_string ("sigcode-meaning", _("ADI disabled"));
+      uiout->text (_(" while accessing address "));
+      uiout->field_fmt ("bound-access", "%s", paddress (gdbarch, addr));
+      break;
+    case SEGV_ADIDERR:	/* disrupting mismatch */
+      uiout->text ("\n");
+      uiout->field_string ("sigcode-meaning", _("ADI deferred mismatch"));
+      uiout->text (_(" while accessing address "));
+      uiout->field_fmt ("bound-access", "%s", paddress (gdbarch, addr));
+      break;
+    case SEGV_ADIPERR:	/* precise mismatch */
+      uiout->text ("\n");
+      uiout->field_string ("sigcode-meaning", _("ADI precise mismatch"));
+      uiout->text (_(" while accessing address "));
+      uiout->field_fmt ("bound-access", "%s", paddress (gdbarch, addr));
+      break;
+    default:
+      break;
+    }
+
+}
+
 
 /* Return the address of a system call's alternative return
    address.  */
@@ -338,6 +405,8 @@ sparc64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
   set_xml_syscall_file_name (gdbarch, XML_SYSCALL_FILENAME_SPARC64);
   set_gdbarch_get_syscall_number (gdbarch,
                                   sparc64_linux_get_syscall_number);
+  set_gdbarch_handle_segmentation_fault (gdbarch,
+					 sparc64_linux_handle_segmentation_fault);
 }