[binutils-gdb/gdb-17-branch] GDB: aarch64: Fix inferior function call if GCS is present but disabled

https://sourceware.org/git/gitweb.cgi?p=3Dbinutils-gdb.git;h=3Dcbdcbf506376=
8bd3943eb41cc4e252c9409c25fa

commit cbdcbf5063768bd3943eb41cc4e252c9409c25fa
Author: Thiago Jung Bauermann <[email protected]>
Date:   Wed Jul 8 14:48:54 2026 -0300

    GDB: aarch64: Fix inferior function call if GCS is present but disabled
   =20
    On AArch64, even if the Guarded Control Stack feature is present on the
    system the inferior may not have enabled it.
   =20
    There's a bug in GDB's GCS support in that if the system supports GCS,
    GDB will always push a GCS entry when doing an inferior function call
    even if the inferior doesn't have it enabled.  This causes inferior
    function calls to fail. E.g.:
   =20
      (gdb) p foo ()
      Can't write to Guarded Control Stack.
   =20
    The error message is because the GCSPR doesn't point to a valid memory
    address.
   =20
    Fix by checking whether GCS is enabled in the inferior before trying to
    push a GCS entry.
   =20
    Regression tested on an aarch64-linux-gnu QEMU VM with GCS present.
   =20
    Approved-By: Luis Machado <[email protected]>
    (cherry picked from commit 4410648da673eb72a456a7a2d925d6201bf2e2a2)

Diff:
---
 gdb/aarch64-tdep.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index 500ac77d75a..84344010b14 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -1939,7 +1939,11 @@ static void
 aarch64_shadow_stack_push (gdbarch *gdbarch, CORE_ADDR new_addr,
 			   regcache *regcache)
 {
-  aarch64_push_gcs_entry (regcache, new_addr);
+  bool gcs_is_enabled;
+
+  (void) gdbarch_get_shadow_stack_pointer (gdbarch, regcache, gcs_is_enabl=
ed);
+  if (gcs_is_enabled)
+    aarch64_push_gcs_entry (regcache, new_addr);
 }
=20
 /* Implement the "push_dummy_call" gdbarch method.  */