i386: Update ___tls_get_addr to preserve vector registers

Compiler generates the following instruction sequence for dynamic TLS
access:

	leal	tls_var@tlsgd(,%ebx,1), %eax
	call	___tls_get_addr@PLT

CALL instruction is transparent to compiler which assumes all registers,
except for EFLAGS, AX, CX, and DX, are unchanged after CALL.  But
___tls_get_addr is a normal function which doesn't preserve any vector
registers.

1. Rename the generic __tls_get_addr function to ___tls_get_addr_internal.
2. Change ___tls_get_addr to a wrapper function with implementations for
FNSAVE, FXSAVE, XSAVE and XSAVEC to save and restore all vector registers.
3. dl-tlsdesc-dynamic.h has:

_dl_tlsdesc_dynamic:
	/* Like all TLS resolvers, preserve call-clobbered registers.
	   We need two scratch regs anyway.  */
	subl	$32, %esp
	cfi_adjust_cfa_offset (32)

It is wrong to use

	movl	%ebx, -28(%esp)
	movl	%esp, %ebx
	cfi_def_cfa_register(%ebx)
	...
	mov	%ebx, %esp
	cfi_def_cfa_register(%esp)
	movl	-28(%esp), %ebx

to preserve EBX on stack.  Fix it with:

	movl	%ebx, 28(%esp)
	movl	%esp, %ebx
	cfi_def_cfa_register(%ebx)
	...
	mov	%ebx, %esp
	cfi_def_cfa_register(%esp)
	movl	28(%esp), %ebx

4. Update _dl_tlsdesc_dynamic to call ___tls_get_addr_internal directly.
5. Add have-test-mtls-traditional to compile tst-tls23-mod.c with
traditional TLS variant to verify the fix.
6. Define DL_RUNTIME_RESOLVE_REALIGN_STACK in sysdeps/x86/sysdep.h.

This fixes BZ #32996.

Co-Authored-By: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

configure

@@ -4931,6 +4931,9 @@ with_fp_cond=1
 # A preconfigure script may define another name to TLS descriptor variant
 mtls_descriptor=gnu2
 
+# A preconfigure script may define another name to traditional TLS variant
+mtls_traditional=gnu
+
 if frags=`ls -d $srcdir/sysdeps/*/preconfigure 2> /dev/null`
 then
   { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for sysdeps preconfigure fragments" >&5
@@ -7490,6 +7493,41 @@ rm -f conftest*
 config_vars="$config_vars
 have-test-mtls-descriptor = $libc_cv_test_mtls_descriptor"
 
+
+cat > conftest.c <<EOF
+$conftest_code
+EOF
+
+saved_CC="$CC"
+CC="$TEST_CC"
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for traditional tls support in testing" >&5
+printf %s "checking for traditional tls support in testing... " >&6; }
+if test ${libc_cv_test_mtls_traditional+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e)     if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -fPIC -mtls-dialect=$mtls_traditional -nostdlib -nostartfiles -shared conftest.c -o conftest 1>&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+    then
+      libc_cv_test_mtls_traditional=$mtls_traditional
+    else
+      libc_cv_test_mtls_traditional=no
+    fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_test_mtls_traditional" >&5
+printf "%s\n" "$libc_cv_test_mtls_traditional" >&6; }
+
+CC="$saved_CC"
+
+rm -f conftest*
+config_vars="$config_vars
+have-test-mtls-traditional = $libc_cv_test_mtls_traditional"
+
 conftest_code="
 void __foo (void)
 {

configure.ac

@@ -483,6 +483,9 @@ with_fp_cond=1
 # A preconfigure script may define another name to TLS descriptor variant
 mtls_descriptor=gnu2
 
+# A preconfigure script may define another name to traditional TLS variant
+mtls_traditional=gnu
+
 dnl Let sysdeps/*/preconfigure act here.
 LIBC_PRECONFIGURE([$srcdir], [for sysdeps])
 
@@ -1401,6 +1404,16 @@ LIBC_TRY_TEST_CC_COMMAND([for tls descriptor support],
 LIBC_CONFIG_VAR([have-test-mtls-descriptor],
 		[$libc_cv_test_mtls_descriptor])
 
+dnl Check if TEST_CC support traditional tls.
+LIBC_TRY_TEST_CC_COMMAND([for traditional tls support],
+  [$conftest_code],
+  [-fPIC -mtls-dialect=$mtls_traditional -nostdlib -nostartfiles -shared],
+  libc_cv_test_mtls_traditional,
+  [libc_cv_test_mtls_traditional=$mtls_traditional],
+  [libc_cv_test_mtls_traditional=no])
+LIBC_CONFIG_VAR([have-test-mtls-traditional],
+		[$libc_cv_test_mtls_traditional])
+
 dnl clang emits an warning for a double alias redirection, to warn the
 dnl original symbol is sed even when weak definition overrides it.
 dnl It is a usual pattern for weak_alias, where multiple alias point to

elf/Makefile

@@ -496,6 +496,7 @@ tests += \
   tst-tls21 \
   tst-tls22 \
   tst-tls22-gnu2 \
+  tst-tls23 \
   tst-tlsalign \
   tst-tlsalign-extern \
   tst-tlsgap \
@@ -1023,6 +1024,7 @@ modules-names += \
   tst-tls22-mod1-gnu2 \
   tst-tls22-mod2 \
   tst-tls22-mod2-gnu2 \
+  tst-tls23-mod \
   tst-tlsalign-lib \
   tst-tlsgap-mod0 \
   tst-tlsgap-mod1 \
@@ -3410,6 +3412,13 @@ tst-tls22-mod1-gnu2.so-no-z-defs = yes
 tst-tls22-mod2.so-no-z-defs = yes
 tst-tls22-mod2-gnu2.so-no-z-defs = yes
 
+$(objpfx)tst-tls23: $(shared-thread-library)
+$(objpfx)tst-tls23.out: $(objpfx)tst-tls23-mod.so
+
+ifneq (no,$(have-test-mtls-traditional))
+CFLAGS-tst-tls23-mod.c += -mtls-dialect=$(have-test-mtls-traditional)
+endif
+
 ifeq ($(have-test-cc-cflags-fsemantic-interposition),yes)
 # Compiler may default to -fno-semantic-interposition.  These modules
 # must be compiled with -fsemantic-interposition.

elf/tst-tls23-mod.c

@@ -0,0 +1,32 @@
+/* DSO used by tst-tls23.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <tst-tls23.h>
+
+__thread struct tls tls_var0 __attribute__ ((visibility ("hidden")));
+
+struct tls *
+apply_tls (struct tls *p)
+{
+  INIT_TLS_CALL ();
+  BEFORE_TLS_CALL ();
+  tls_var0 = *p;
+  struct tls *ret = &tls_var0;
+  AFTER_TLS_CALL ();
+  return ret;
+}

elf/tst-tls23.c

@@ -0,0 +1,106 @@
+/* Test that __tls_get_addr preserves caller-saved registers.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <dlfcn.h>
+#include <pthread.h>
+#include <support/xdlfcn.h>
+#include <support/xthread.h>
+#include <support/check.h>
+#include <support/test-driver.h>
+#include <tst-tls23.h>
+
+#ifndef IS_SUPPORTED
+# define IS_SUPPORTED() true
+#endif
+
+/* An architecture can define it to clobber caller-saved registers in
+   malloc below to verify that __tls_get_addr won't change caller-saved
+   registers.  */
+#ifndef PREPARE_MALLOC
+# define PREPARE_MALLOC()
+#endif
+
+extern void * __libc_malloc (size_t);
+
+size_t malloc_counter = 0;
+
+void *
+malloc (size_t n)
+{
+  PREPARE_MALLOC ();
+  malloc_counter++;
+  return __libc_malloc (n);
+}
+
+static void *mod;
+static const char *modname = "tst-tls23-mod.so";
+
+static void
+open_mod (void)
+{
+  mod = xdlopen (modname, RTLD_LAZY);
+  printf ("open %s\n", modname);
+}
+
+static void
+close_mod (void)
+{
+  xdlclose (mod);
+  mod = NULL;
+  printf ("close %s\n", modname);
+}
+
+static void
+access_mod (const char *sym)
+{
+  struct tls var = { -4, -4, -4, -4 };
+  struct tls *(*f) (struct tls *) = xdlsym (mod, sym);
+  /* Check that our malloc is called.  */
+  malloc_counter = 0;
+  struct tls *p = f (&var);
+  TEST_VERIFY (malloc_counter != 0);
+  printf ("access %s: %s() = %p\n", modname, sym, p);
+  TEST_VERIFY_EXIT (memcmp (p, &var, sizeof (var)) == 0);
+  ++(p->a);
+}
+
+static void *
+start (void *arg)
+{
+  access_mod ("apply_tls");
+  return arg;
+}
+
+static int
+do_test (void)
+{
+  if (!IS_SUPPORTED ())
+    return EXIT_UNSUPPORTED;
+
+  open_mod ();
+  pthread_t t = xpthread_create (NULL, start, NULL);
+  xpthread_join (t);
+  close_mod ();
+
+  return 0;
+}
+
+#include <support/test-driver.c>

elf/tst-tls23.h

@@ -1,5 +1,5 @@
-/* x86-64 PLT trampoline register save macros.
+/* Test that __tls_get_addr preserves caller-saved registers.
-   Copyright (C) 2024-2025 Free Software Foundation, Inc.
+   Copyright (C) 2025 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -16,19 +16,25 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#ifndef DL_STACK_ALIGNMENT
+#include <stdint.h>
-/* Due to GCC bug:
 
-   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58066
+struct tls
+{
+  int64_t a, b, c, d;
+};
 
-   __tls_get_addr may be called with 8-byte stack alignment.  Although
+extern struct tls *apply_tls (struct tls *);
-   this bug has been fixed in GCC 4.9.4, 5.3 and 6, we can't assume
+
-   that stack will be always aligned at 16 bytes.  */
+/* An architecture can define them to verify that caller-saved registers
-# define DL_STACK_ALIGNMENT 8
+   aren't changed by __tls_get_addr.  */
+#ifndef INIT_TLS_CALL
+# define INIT_TLS_CALL()
 #endif
 
-/* True if _dl_runtime_resolve should align stack for STATE_SAVE or align
+#ifndef BEFORE_TLS_CALL
-   stack to 16 bytes before calling _dl_fixup.  */
+# define BEFORE_TLS_CALL()
-#define DL_RUNTIME_RESOLVE_REALIGN_STACK \
+#endif
-  (STATE_SAVE_ALIGNMENT > DL_STACK_ALIGNMENT \
+
-   || 16 > DL_STACK_ALIGNMENT)
+#ifndef AFTER_TLS_CALL
+# define AFTER_TLS_CALL()
+#endif

sysdeps/aarch64/preconfigure

@@ -3,5 +3,6 @@ aarch64*)
 	base_machine=aarch64
 	machine=aarch64
 	mtls_descriptor=desc
+	mtls_traditional=trad
 	;;
 esac

sysdeps/i386/Makefile

@@ -30,7 +30,9 @@ stack-align-test-flags += -malign-double
 endif
 
 ifeq ($(subdir),elf)
-sysdep-dl-routines += tlsdesc dl-tlsdesc
+sysdep-dl-routines += \
+  dl-tls-get-addr \
+# sysdep-dl-routines
 
 tests += tst-audit3
 modules-names += tst-auditmod3a tst-auditmod3b

sysdeps/i386/dl-tls-get-addr.c

@@ -0,0 +1,68 @@
+/* Ifunc selector for ___tls_get_addr.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifdef SHARED
+# define ___tls_get_addr __redirect____tls_get_addr
+# include <dl-tls.h>
+# undef ___tls_get_addr
+# undef __tls_get_addr
+
+# define SYMBOL_NAME ___tls_get_addr
+# include <init-arch.h>
+
+extern __typeof (REDIRECT_NAME) OPTIMIZE (fnsave) attribute_hidden;
+extern __typeof (REDIRECT_NAME) OPTIMIZE (fxsave) attribute_hidden;
+extern __typeof (REDIRECT_NAME) OPTIMIZE (xsave) attribute_hidden;
+extern __typeof (REDIRECT_NAME) OPTIMIZE (xsavec) attribute_hidden;
+
+static inline void *
+IFUNC_SELECTOR (void)
+{
+  const struct cpu_features* cpu_features = __get_cpu_features ();
+
+  if (cpu_features->xsave_state_size != 0)
+    {
+      if (CPU_FEATURE_USABLE_P (cpu_features, XSAVEC))
+	return OPTIMIZE (xsavec);
+      else
+	return OPTIMIZE (xsave);
+    }
+  else if (CPU_FEATURE_USABLE_P (cpu_features, FXSR))
+    return OPTIMIZE (fxsave);
+  return OPTIMIZE (fnsave);
+}
+
+libc_ifunc_redirected (__redirect____tls_get_addr, ___tls_get_addr,
+		       IFUNC_SELECTOR ());
+
+/* The special thing about the x86 TLS ABI is that we have two
+   variants of the __tls_get_addr function with different calling
+   conventions.  The GNU version, which we are mostly concerned here,
+   takes the parameter in a register.  The name is changed by adding
+   an additional underscore at the beginning.  The Sun version uses
+   the normal calling convention.  */
+
+rtld_hidden_proto (___tls_get_addr)
+rtld_hidden_def (___tls_get_addr)
+
+void *
+__tls_get_addr (tls_index *ti)
+{
+  return ___tls_get_addr (ti);
+}
+#endif

sysdeps/i386/dl-tls.h

@@ -37,34 +37,14 @@ typedef struct dl_tls_index
 /* This is the prototype for the GNU version.  */
 extern void *___tls_get_addr (tls_index *ti)
      __attribute__ ((__regparm__ (1)));
-extern void *___tls_get_addr_internal (tls_index *ti)
-     __attribute__ ((__regparm__ (1))) attribute_hidden;
-
 # if IS_IN (rtld)
-/* The special thing about the x86 TLS ABI is that we have two
-   variants of the __tls_get_addr function with different calling
-   conventions.  The GNU version, which we are mostly concerned here,
-   takes the parameter in a register.  The name is changed by adding
-   an additional underscore at the beginning.  The Sun version uses
-   the normal calling convention.  */
-void *
-__tls_get_addr (tls_index *ti)
-{
-  return ___tls_get_addr_internal (ti);
-}
-
-
 /* Prepare using the definition of __tls_get_addr in the generic
    version of this file.  */
-# define __tls_get_addr __attribute__ ((__regparm__ (1))) ___tls_get_addr
+# define __tls_get_addr \
-strong_alias (___tls_get_addr, ___tls_get_addr_internal)
+    __attribute__ ((__regparm__ (1))) ___tls_get_addr_internal
-rtld_hidden_proto (___tls_get_addr)
+# else
-rtld_hidden_def (___tls_get_addr)
-#else
-
 /* Users should get the better interface.  */
-# define __tls_get_addr ___tls_get_addr
+#  define __tls_get_addr ___tls_get_addr
-
 # endif
 #endif
 

sysdeps/i386/dl-tlsdesc-dynamic.h

@@ -16,34 +16,6 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#undef REGISTER_SAVE_AREA
-
-#if !defined USE_FNSAVE && (STATE_SAVE_ALIGNMENT % 16) != 0
-# error STATE_SAVE_ALIGNMENT must be multiple of 16
-#endif
-
-#if DL_RUNTIME_RESOLVE_REALIGN_STACK
-# ifdef USE_FNSAVE
-#  error USE_FNSAVE shouldn't be defined
-# endif
-# ifdef USE_FXSAVE
-/* Use fxsave to save all registers.  */
-#  define REGISTER_SAVE_AREA	512
-# endif
-#else
-# ifdef USE_FNSAVE
-/* Use fnsave to save x87 FPU stack registers.  */
-#  define REGISTER_SAVE_AREA	108
-# else
-#  ifndef USE_FXSAVE
-#   error USE_FXSAVE must be defined
-#  endif
-/* Use fxsave to save all registers.  Add 12 bytes to align the stack
-   to 16 bytes.  */
-#  define REGISTER_SAVE_AREA	(512 + 12)
-# endif
-#endif
-
 	.hidden _dl_tlsdesc_dynamic
 	.global	_dl_tlsdesc_dynamic
 	.type	_dl_tlsdesc_dynamic,@function
@@ -104,85 +76,7 @@ _dl_tlsdesc_dynamic:
 	ret
 	.p2align 4,,7
 2:
-	cfi_adjust_cfa_offset (32)
+#include "tls-get-addr-wrapper.h"
-#if DL_RUNTIME_RESOLVE_REALIGN_STACK
-	movl	%ebx, -28(%esp)
-	movl	%esp, %ebx
-	cfi_def_cfa_register(%ebx)
-	and	$-STATE_SAVE_ALIGNMENT, %esp
-#endif
-#ifdef REGISTER_SAVE_AREA
-	subl	$REGISTER_SAVE_AREA, %esp
-# if !DL_RUNTIME_RESOLVE_REALIGN_STACK
-	cfi_adjust_cfa_offset(REGISTER_SAVE_AREA)
-# endif
-#else
-# if !DL_RUNTIME_RESOLVE_REALIGN_STACK
-#  error DL_RUNTIME_RESOLVE_REALIGN_STACK must be true
-# endif
-	/* Allocate stack space of the required size to save the state.  */
-	LOAD_PIC_REG (cx)
-	subl	RTLD_GLOBAL_RO_DL_X86_CPU_FEATURES_OFFSET+XSAVE_STATE_SIZE_OFFSET+_rtld_local_ro@GOTOFF(%ecx), %esp
-#endif
-#ifdef USE_FNSAVE
-	fnsave	(%esp)
-#elif defined USE_FXSAVE
-	fxsave	(%esp)
-#else
-	/* Save the argument for ___tls_get_addr in EAX.  */
-	movl	%eax, %ecx
-	movl	$TLSDESC_CALL_STATE_SAVE_MASK, %eax
-	xorl	%edx, %edx
-	/* Clear the XSAVE Header.  */
-# ifdef USE_XSAVE
-	movl	%edx, (512)(%esp)
-	movl	%edx, (512 + 4 * 1)(%esp)
-	movl	%edx, (512 + 4 * 2)(%esp)
-	movl	%edx, (512 + 4 * 3)(%esp)
-# endif
-	movl	%edx, (512 + 4 * 4)(%esp)
-	movl	%edx, (512 + 4 * 5)(%esp)
-	movl	%edx, (512 + 4 * 6)(%esp)
-	movl	%edx, (512 + 4 * 7)(%esp)
-	movl	%edx, (512 + 4 * 8)(%esp)
-	movl	%edx, (512 + 4 * 9)(%esp)
-	movl	%edx, (512 + 4 * 10)(%esp)
-	movl	%edx, (512 + 4 * 11)(%esp)
-	movl	%edx, (512 + 4 * 12)(%esp)
-	movl	%edx, (512 + 4 * 13)(%esp)
-	movl	%edx, (512 + 4 * 14)(%esp)
-	movl	%edx, (512 + 4 * 15)(%esp)
-# ifdef USE_XSAVE
-	xsave	(%esp)
-# else
-	xsavec	(%esp)
-# endif
-	/* Restore the argument for ___tls_get_addr in EAX.  */
-	movl	%ecx, %eax
-#endif
-	call	HIDDEN_JUMPTARGET (___tls_get_addr)
-	/* Get register content back.  */
-#ifdef USE_FNSAVE
-	frstor	(%esp)
-#elif defined USE_FXSAVE
-	fxrstor	(%esp)
-#else
-	/* Save and retore ___tls_get_addr return value stored in EAX.  */
-	movl	%eax, %ecx
-	movl	$TLSDESC_CALL_STATE_SAVE_MASK, %eax
-	xorl	%edx, %edx
-	xrstor	(%esp)
-	movl	%ecx, %eax
-#endif
-#if DL_RUNTIME_RESOLVE_REALIGN_STACK
-	mov	%ebx, %esp
-	cfi_def_cfa_register(%esp)
-	movl	-28(%esp), %ebx
-	cfi_restore(%ebx)
-#else
-	addl	$REGISTER_SAVE_AREA, %esp
-	cfi_adjust_cfa_offset(-REGISTER_SAVE_AREA)
-#endif
 	jmp	1b
 	cfi_endproc
 	.size	_dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic

sysdeps/i386/dl-tlsdesc.S

@@ -22,23 +22,6 @@
 #include <features-offsets.h>
 #include "tlsdesc.h"
 
-#ifndef DL_STACK_ALIGNMENT
-/* Due to GCC bug:
-
-   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58066
-
-   __tls_get_addr may be called with 4-byte stack alignment.  Although
-   this bug has been fixed in GCC 4.9.4, 5.3 and 6, we can't assume
-   that stack will be always aligned at 16 bytes.  */
-# define DL_STACK_ALIGNMENT 4
-#endif
-
-/* True if _dl_tlsdesc_dynamic should align stack for STATE_SAVE or align
-   stack to MINIMUM_ALIGNMENT bytes before calling ___tls_get_addr.  */
-#define DL_RUNTIME_RESOLVE_REALIGN_STACK \
-  (STATE_SAVE_ALIGNMENT > DL_STACK_ALIGNMENT \
-   || MINIMUM_ALIGNMENT > DL_STACK_ALIGNMENT)
-
 	.text
 
      /* This function is used to compute the TP offset for symbols in

sysdeps/i386/tls-get-addr-wrapper.h

@@ -0,0 +1,127 @@
+/* Wrapper of i386 ___tls_get_addr to save and restore vector registers.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#undef REGISTER_SAVE_AREA
+
+#if !defined USE_FNSAVE && (STATE_SAVE_ALIGNMENT % 16) != 0
+# error STATE_SAVE_ALIGNMENT must be multiple of 16
+#endif
+
+#if DL_RUNTIME_RESOLVE_REALIGN_STACK
+# ifdef USE_FNSAVE
+#  error USE_FNSAVE shouldn't be defined
+# endif
+# ifdef USE_FXSAVE
+/* Use fxsave to save all registers.  */
+#  define REGISTER_SAVE_AREA	512
+# endif
+#else
+# ifdef USE_FNSAVE
+/* Use fnsave to save x87 FPU stack registers.  */
+#  define REGISTER_SAVE_AREA	108
+# else
+#  ifndef USE_FXSAVE
+#   error USE_FXSAVE must be defined
+#  endif
+/* Use fxsave to save all registers.  Add 12 bytes to align the stack
+   to 16 bytes.  */
+#  define REGISTER_SAVE_AREA	(512 + 12)
+# endif
+#endif
+
+#if DL_RUNTIME_RESOLVE_REALIGN_STACK
+	movl	%ebx, 28(%esp)
+	movl	%esp, %ebx
+	cfi_def_cfa_register(%ebx)
+	and	$-STATE_SAVE_ALIGNMENT, %esp
+#endif
+#ifdef REGISTER_SAVE_AREA
+	subl	$REGISTER_SAVE_AREA, %esp
+# if !DL_RUNTIME_RESOLVE_REALIGN_STACK
+	cfi_adjust_cfa_offset(REGISTER_SAVE_AREA)
+# endif
+#else
+# if !DL_RUNTIME_RESOLVE_REALIGN_STACK
+#  error DL_RUNTIME_RESOLVE_REALIGN_STACK must be true
+# endif
+	/* Allocate stack space of the required size to save the state.  */
+	LOAD_PIC_REG (cx)
+	subl	RTLD_GLOBAL_RO_DL_X86_CPU_FEATURES_OFFSET \
+		+XSAVE_STATE_SIZE_OFFSET+_rtld_local_ro@GOTOFF(%ecx), %esp
+#endif
+#ifdef USE_FNSAVE
+	fnsave	(%esp)
+#elif defined USE_FXSAVE
+	fxsave	(%esp)
+#else
+	/* Save the argument for ___tls_get_addr in EAX.  */
+	movl	%eax, %ecx
+	movl	$TLSDESC_CALL_STATE_SAVE_MASK, %eax
+	xorl	%edx, %edx
+	/* Clear the XSAVE Header.  */
+# ifdef USE_XSAVE
+	movl	%edx, (512)(%esp)
+	movl	%edx, (512 + 4 * 1)(%esp)
+	movl	%edx, (512 + 4 * 2)(%esp)
+	movl	%edx, (512 + 4 * 3)(%esp)
+# endif
+	movl	%edx, (512 + 4 * 4)(%esp)
+	movl	%edx, (512 + 4 * 5)(%esp)
+	movl	%edx, (512 + 4 * 6)(%esp)
+	movl	%edx, (512 + 4 * 7)(%esp)
+	movl	%edx, (512 + 4 * 8)(%esp)
+	movl	%edx, (512 + 4 * 9)(%esp)
+	movl	%edx, (512 + 4 * 10)(%esp)
+	movl	%edx, (512 + 4 * 11)(%esp)
+	movl	%edx, (512 + 4 * 12)(%esp)
+	movl	%edx, (512 + 4 * 13)(%esp)
+	movl	%edx, (512 + 4 * 14)(%esp)
+	movl	%edx, (512 + 4 * 15)(%esp)
+# ifdef USE_XSAVE
+	xsave	(%esp)
+# else
+	xsavec	(%esp)
+# endif
+	/* Restore the argument for ___tls_get_addr in EAX.  */
+	movl	%ecx, %eax
+#endif
+	call	___tls_get_addr_internal
+	/* Get register content back.  */
+#ifdef USE_FNSAVE
+	frstor	(%esp)
+#elif defined USE_FXSAVE
+	fxrstor	(%esp)
+#else
+	/* Save and retore ___tls_get_addr return value stored in EAX.  */
+	movl	%eax, %ecx
+	movl	$TLSDESC_CALL_STATE_SAVE_MASK, %eax
+	xorl	%edx, %edx
+	xrstor	(%esp)
+	movl	%ecx, %eax
+#endif
+#if DL_RUNTIME_RESOLVE_REALIGN_STACK
+	mov	%ebx, %esp
+	cfi_def_cfa_register(%esp)
+	movl	28(%esp), %ebx
+	cfi_restore(%ebx)
+#else
+	addl	$REGISTER_SAVE_AREA, %esp
+	cfi_adjust_cfa_offset(-REGISTER_SAVE_AREA)
+#endif
+
+#undef STATE_SAVE_ALIGNMENT

sysdeps/i386/tls_get_addr.S

@@ -0,0 +1,57 @@
+/* Thread-local storage handling in the ELF dynamic linker.  i386 version.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+#include <tls.h>
+#include <cpu-features-offsets.h>
+#include <features-offsets.h>
+
+	.text
+#ifdef SHARED
+# define USE_FNSAVE
+# define MINIMUM_ALIGNMENT	4
+# define STATE_SAVE_ALIGNMENT	4
+# define ___tls_get_addr	_____tls_get_addr_fnsave
+# include "tls_get_addr.h"
+# undef ___tls_get_addr
+# undef MINIMUM_ALIGNMENT
+# undef USE_FNSAVE
+
+# define MINIMUM_ALIGNMENT	16
+
+# define USE_FXSAVE
+# define STATE_SAVE_ALIGNMENT	16
+# define ___tls_get_addr	_____tls_get_addr_fxsave
+# include "tls_get_addr.h"
+# undef ___tls_get_addr
+# undef USE_FXSAVE
+
+# define USE_XSAVE
+# define STATE_SAVE_ALIGNMENT	64
+# define ___tls_get_addr	_____tls_get_addr_xsave
+# include "tls_get_addr.h"
+# undef ___tls_get_addr
+# undef USE_XSAVE
+
+# define USE_XSAVEC
+# define STATE_SAVE_ALIGNMENT	64
+# define ___tls_get_addr	_____tls_get_addr_xsavec
+# include "tls_get_addr.h"
+# undef ___tls_get_addr
+# undef USE_XSAVEC
+#endif /* SHARED */

sysdeps/i386/tls_get_addr.h

@@ -0,0 +1,42 @@
+/* Thread-local storage handling in the ELF dynamic linker.  i386 version.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+	.hidden ___tls_get_addr
+	.global	___tls_get_addr
+	.type	___tls_get_addr,@function
+
+	/* This function is a wrapper of ___tls_get_addr_internal to
+	   preserve caller-saved vector registers.  */
+
+	cfi_startproc
+	.align 16
+___tls_get_addr:
+	/* Like all TLS resolvers, preserve call-clobbered registers.
+	   We need two scratch regs anyway.  */
+	subl	$32, %esp
+	cfi_adjust_cfa_offset (32)
+	movl	%ecx, 20(%esp)
+	movl	%edx, 24(%esp)
+#include "tls-get-addr-wrapper.h"
+	movl	20(%esp), %ecx
+	movl	24(%esp), %edx
+	addl	$32, %esp
+	cfi_adjust_cfa_offset (-32)
+	ret
+	cfi_endproc
+	.size	___tls_get_addr, .-___tls_get_addr

sysdeps/loongarch/preconfigure

@@ -44,6 +44,7 @@ loongarch*)
 
     base_machine=loongarch
     mtls_descriptor=desc
+    mtls_traditional=trad
     ;;
 esac
 

sysdeps/loongarch/preconfigure.ac

@@ -42,6 +42,7 @@ loongarch*)
 
     base_machine=loongarch
     mtls_descriptor=desc
+    mtls_traditional=trad
     ;;
 esac
 

sysdeps/powerpc/Makefile

@@ -28,6 +28,11 @@ tst-cache-ppc-static-dlopen-ENV = LD_LIBRARY_PATH=$(objpfx):$(common-objpfx):$(c
 $(objpfx)tst-cache-ppc-static-dlopen.out: $(objpfx)mod-cache-ppc.so
 
 $(objpfx)tst-cache-ppc: $(objpfx)mod-cache-ppc.so
+
+# The test checks if the __tls_get_addr does not clobber caller-saved
+# register, so disable the powerpc specific optimization to force a
+# __tls_get_addr call.
+LDFLAGS-tst-tls23-mod.so = -Wl,--no-tls-get-addr-optimize
 endif
 
 ifneq (no,$(multi-arch))

sysdeps/x86/Makefile

@@ -4,7 +4,13 @@ endif
 
 ifeq ($(subdir),elf)
 sysdep_routines += get-cpuid-feature-leaf
-sysdep-dl-routines += dl-get-cpu-features
+sysdep-dl-routines += \
+  dl-get-cpu-features \
+  dl-tlsdesc \
+  tls_get_addr \
+  tlsdesc \
+# sysdep-dl-routines
+
 sysdep_headers += \
   bits/platform/features.h \
   bits/platform/x86.h \
@@ -113,6 +119,14 @@ $(objpfx)tst-gnu2-tls2-x86-noxsavexsavec.out: \
   $(objpfx)tst-gnu2-tls2mod0.so \
   $(objpfx)tst-gnu2-tls2mod1.so \
   $(objpfx)tst-gnu2-tls2mod2.so
+
+CFLAGS-tst-tls23.c += -msse2
+CFLAGS-tst-tls23-mod.c += -msse2 -mtune=haswell
+
+LDFLAGS-tst-tls23 += -rdynamic
+tst-tls23-mod.so-no-z-defs = yes
+
+$(objpfx)tst-tls23-mod.so: $(libsupport)
 endif
 
 ifeq ($(subdir),math)

sysdeps/x86/sysdep.h

@@ -183,6 +183,29 @@
 
 #define atom_text_section .section ".text.atom", "ax"
 
+#ifndef DL_STACK_ALIGNMENT
+/* Due to GCC bug:
+
+   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58066
+
+   __tls_get_addr may be called with 8-byte/4-byte stack alignment.
+   Although this bug has been fixed in GCC 4.9.4, 5.3 and 6, we can't
+   assume that stack will be always aligned at 16 bytes.  */
+# ifdef __x86_64__
+#  define DL_STACK_ALIGNMENT 8
+#  define MINIMUM_ALIGNMENT 16
+# else
+#  define DL_STACK_ALIGNMENT 4
+# endif
+#endif
+
+/* True if _dl_runtime_resolve/_dl_tlsdesc_dynamic should align stack for
+   STATE_SAVE or align stack to MINIMUM_ALIGNMENT bytes before calling
+   _dl_fixup/__tls_get_addr.  */
+#define DL_RUNTIME_RESOLVE_REALIGN_STACK \
+  (STATE_SAVE_ALIGNMENT > DL_STACK_ALIGNMENT \
+   || MINIMUM_ALIGNMENT > DL_STACK_ALIGNMENT)
+
 #endif	/* __ASSEMBLER__ */
 
 #endif	/* _X86_SYSDEP_H */

sysdeps/x86/tst-tls23.c

@@ -0,0 +1,22 @@
+#ifndef __x86_64__
+#include <sys/platform/x86.h>
+
+#define IS_SUPPORTED() CPU_FEATURE_ACTIVE (SSE2)
+#endif
+
+/* Set XMM0...XMM7 to all 1s.  */
+#define PREPARE_MALLOC()					\
+{								\
+  asm volatile ("pcmpeqd %%xmm0, %%xmm0" : : : "xmm0" );	\
+  asm volatile ("pcmpeqd %%xmm1, %%xmm1" : : : "xmm1" );	\
+  asm volatile ("pcmpeqd %%xmm2, %%xmm2" : : : "xmm2" );	\
+  asm volatile ("pcmpeqd %%xmm3, %%xmm3" : : : "xmm3" );	\
+  asm volatile ("pcmpeqd %%xmm4, %%xmm4" : : : "xmm4" );	\
+  asm volatile ("pcmpeqd %%xmm5, %%xmm5" : : : "xmm5" );	\
+  asm volatile ("pcmpeqd %%xmm6, %%xmm6" : : : "xmm6" );	\
+  asm volatile ("pcmpeqd %%xmm7, %%xmm7" : : : "xmm7" );	\
+}
+
+#include <elf/tst-tls23.c>
+
+v2di v1, v2, v3;

sysdeps/x86/tst-tls23.h

@@ -0,0 +1,35 @@
+/* Test that __tls_get_addr preserves XMM registers.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <support/check.h>
+
+typedef long long v2di __attribute__((vector_size(16)));
+extern v2di v1, v2, v3;
+
+#define BEFORE_TLS_CALL()					\
+  v1 = __extension__(v2di){0, 0};				\
+  v2 = __extension__(v2di){0, 0};
+
+#define AFTER_TLS_CALL()					\
+  v3 = __extension__(v2di){0, 0};				\
+  asm volatile ("" : "+x" (v3));				\
+  union { v2di x; long long a[2]; } u;				\
+  u.x = v3;							\
+  TEST_VERIFY_EXIT (u.a[0] == 0 && u.a[1] == 0);
+
+#include <elf/tst-tls23.h>

sysdeps/x86_64/Makefile

@@ -41,9 +41,6 @@ ifeq ($(subdir),elf)
 CFLAGS-.os += $(if $(filter $(@F),$(patsubst %,%.os,$(all-rtld-routines))),\
 		   -mno-mmx)
 
-sysdep-dl-routines += tlsdesc dl-tlsdesc tls_get_addr
-
-tests += ifuncmain8
 modules-names += ifuncmod8
 
 $(objpfx)ifuncmain8: $(objpfx)ifuncmod8.so

sysdeps/x86_64/dl-tlsdesc.S

@@ -22,7 +22,6 @@
 #include <features-offsets.h>
 #include <isa-level.h>
 #include "tlsdesc.h"
-#include "dl-trampoline-save.h"
 
 /* Area on stack to save and restore registers used for parameter
    passing when calling _dl_tlsdesc_dynamic.  */

sysdeps/x86_64/dl-trampoline.S

@@ -22,7 +22,6 @@
 #include <features-offsets.h>
 #include <link-defines.h>
 #include <isa-level.h>
-#include "dl-trampoline-save.h"
 
 /* Area on stack to save and restore registers used for parameter
    passing when calling _dl_fixup.  */