diff mbox series

[1/4] gdb: aarch64: Remove MTE address checking from get_memtag

Message ID 20240328070055.2578783-2-gustavo.romero@linaro.org
State New
Headers
Series Add another way to check for MTE-tagged addresses on remote targets |

Checks

Context Check Description
linaro-tcwg-bot/tcwg_gdb_build--master-aarch64 success Testing passed
linaro-tcwg-bot/tcwg_gdb_build--master-arm success Testing passed

Commit Message

Gustavo Romero March 28, 2024, 7 a.m. UTC 
  This commit removes aarch64_linux_tagged_address_p from
aarch64_linux_get_memtag. aarch64_linux_tagged_address_p checks if an
address is tagged (MTE) or not.

The check is redundant because aarch64_linux_get_memtag is always called
from the upper layers (i.e. from printcmd.c via gdbarch hook
gdbarch_get_memtag) after either gdbarch_tagged_address_p (that already
points to aarch64_linux_tagged_address_p) has been called or
after should_validate_memtags (that calls gdbarch_tagged_address_p at
the end) has been called, so the address is already checked. Hence:

a) in print_command_1, aarch64_linux_get_memtag (via gdbarch_get_memtag
hook) is called but only after should_validate_memtags, which calls
gdbarch_tagged_address_p;

b) in do_examine, aarch64_linux_get_memtag is also called only after
gdbarch_tagged_address_p is directly called;

c) in memory_tag_check_command, gdbarch_get_memtag is called -- tags
matching or not -- after the initial check via direct call to
gdbarch_tagged_address_p;

d) in memory_tag_print_tag_command, address is checked directly via
gdbarch_tagged_address_p before gdbarch_get_memtag is called.

Also, because after this change the address checking only happens at the
upper layer it now allows the address checking to be specialized easily
per target, via a target hook.

Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
---
 gdb/aarch64-linux-tdep.c | 4 ----
 1 file changed, 4 deletions(-)
diff mbox series

Patch

diff --git a/gdb/aarch64-linux-tdep.c b/gdb/aarch64-linux-tdep.c
index 0b9784f38e4..50055ac3f48 100644
--- a/gdb/aarch64-linux-tdep.c
+++ b/gdb/aarch64-linux-tdep.c
@@ -2575,10 +2575,6 @@  aarch64_linux_get_memtag (struct gdbarch *gdbarch, struct value *address,
     tag = aarch64_mte_get_ltag (addr);
   else
     {
-      /* Make sure we are dealing with a tagged address to begin with.  */
-      if (!aarch64_linux_tagged_address_p (gdbarch, address))
-	return nullptr;
-
       /* Remove the top byte.  */
       addr = gdbarch_remove_non_address_bits (gdbarch, addr);
       std::optional<CORE_ADDR> atag = aarch64_mte_get_atag (addr);