[glibc] hurd: Only init early static TLS if it's used to store stack or pointer guards

[glibc] hurd: Only init early static TLS if it's used to store stack or pointer guards

[Samuel Thibault]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=4145de65f696ae06be72fadd67967be556c31ac2

commit 4145de65f696ae06be72fadd67967be556c31ac2
Author: Sergey Bugaev <bugaevc@gmail.com>
Date:   Wed Jan 3 20:14:43 2024 +0300

    hurd: Only init early static TLS if it's used to store stack or pointer guards
    
    This is the case on both x86 architectures, but not on AArch64.
    
    Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
    Message-ID: <20240103171502.1358371-11-bugaevc@gmail.com>

Diff:
---
 sysdeps/mach/hurd/init-first.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/sysdeps/mach/hurd/init-first.c b/sysdeps/mach/hurd/init-first.c
index 8526191692..26ccd37e55 100644
--- a/sysdeps/mach/hurd/init-first.c
+++ b/sysdeps/mach/hurd/init-first.c
@@ -38,7 +38,16 @@ extern int __libc_argc attribute_hidden;
 extern char **__libc_argv attribute_hidden;
 extern char **_dl_argv;
 
-#ifndef SHARED
+#if !defined (SHARED) && (defined (THREAD_SET_STACK_GUARD) || defined (THREAD_SET_POINTER_GUARD))
+/* In the static case, we need to set up TLS early so that the stack
+   protection guard can be read at from TLS by the GCC-generated snippets,
+   on architectures that store the guard in TLS and not globally.  */
+# define USE_INIT1_TCBHEAD 1
+#else
+# define USE_INIT1_TCBHEAD 0
+#endif
+
+#if USE_INIT1_TCBHEAD
 static tcbhead_t __init1_tcbhead;
 #endif
 
@@ -153,9 +162,7 @@ first_init (void)
   /* Initialize data structures so we can do RPCs.  */
   __mach_init ();
 
-#ifndef SHARED
-  /* In the static case, we need to set up TLS early so that the stack
-     protection guard can be read at from TLS by the GCC-generated snippets.  */
+#if USE_INIT1_TCBHEAD
   _hurd_tls_init (&__init1_tcbhead, 0);
 #endif