[COMMITTED 2.40 2/2] x32/cet: Support shadow stack during startup for Linux 6.10

[H.J. Lu]

Use RXX_LP in RTLD_START_ENABLE_X86_FEATURES.  Support shadow stack during
startup for Linux 6.10:

commit 2883f01ec37dd8668e7222dfdb5980c86fdfe277
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Mar 15 07:04:33 2024 -0700

    x86/shstk: Enable shadow stacks for x32

    1. Add shadow stack support to x32 signal.
    2. Use the 64-bit map_shadow_stack syscall for x32.
    3. Set up shadow stack for x32.

Add the map_shadow_stack system call to <fixup-asm-unistd.h> and regenerate
arch-syscall.h.  Tested on Intel Tiger Lake with CET enabled x32.  There
are no regressions with CET enabled x86-64.  There are no changes in CET
enabled x86-64 _dl_start_user.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
(cherry picked from commit 8344c1f5514b1b5b1c8c6e48f4b802653bd23b71)
---
 sysdeps/unix/sysv/linux/x86_64/dl-cet.h               | 6 +++---
 sysdeps/unix/sysv/linux/x86_64/x32/arch-syscall.h     | 1 +
 sysdeps/unix/sysv/linux/x86_64/x32/fixup-asm-unistd.h | 4 ++++
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/sysdeps/unix/sysv/linux/x86_64/dl-cet.h b/sysdeps/unix/sysv/linux/x86_64/dl-cet.h
index 1fe3133406..b4f7e6c9cd 100644
--- a/sysdeps/unix/sysv/linux/x86_64/dl-cet.h
+++ b/sysdeps/unix/sysv/linux/x86_64/dl-cet.h
@@ -92,9 +92,9 @@ dl_cet_ibt_enabled (void)
 	# Pass GL(dl_x86_feature_1) to _dl_cet_setup_features.\n\
 	movl %edx, %edi\n\
 	# Align stack for the _dl_cet_setup_features call.\n\
-	andq $-16, %rsp\n\
+	and $-16, %" RSP_LP "\n\
 	call _dl_cet_setup_features\n\
 	# Restore %rax and %rsp from %r12 and %r13.\n\
-	movq %r12, %rax\n\
-	movq %r13, %rsp\n\
+	mov %" R12_LP ", %" RAX_LP "\n\
+	mov %" R13_LP ", %" RSP_LP "\n\
 "
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/arch-syscall.h b/sysdeps/unix/sysv/linux/x86_64/x32/arch-syscall.h
index 3040a47d72..df3e22236d 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/arch-syscall.h
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/arch-syscall.h
@@ -155,6 +155,7 @@
 #define __NR_lsm_set_self_attr 1073742284
 #define __NR_lstat 1073741830
 #define __NR_madvise 1073741852
+#define __NR_map_shadow_stack 1073742277
 #define __NR_mbind 1073742061
 #define __NR_membarrier 1073742148
 #define __NR_memfd_create 1073742143
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/fixup-asm-unistd.h b/sysdeps/unix/sysv/linux/x86_64/x32/fixup-asm-unistd.h
index 98124169e6..47fa8af4ce 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/fixup-asm-unistd.h
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/fixup-asm-unistd.h
@@ -15,6 +15,10 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
+#ifndef __NR_map_shadow_stack
+# define __NR_map_shadow_stack 1073742277
+#endif
+
 /* X32 uses the same 64-bit syscall interface for set_thread_area.   */
 #ifndef __NR_set_thread_area
 # define __NR_set_thread_area 1073742029
-- 
2.46.0