mseal sysmap: enable arm64

Provide support for CONFIG_MSEAL_SYSTEM_MAPPINGS on arm64, covering the
vdso, vvar, and compat-mode vectors and sigpage mappings.

Production release testing passes on Android and Chrome OS.

Link: https://lkml.kernel.org/r/20250305021711.3867874-5-jeffxu@google.com
Signed-off-by: Jeff Xu <jeffxu@chromium.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Anna-Maria Behnsen <anna-maria@linutronix.de>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Benjamin Berg <benjamin@sipsolutions.net>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Elliot Hughes <enh@google.com>
Cc: Florian Faineli <f.fainelli@gmail.com>
Cc: Greg Ungerer <gerg@kernel.org>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Jason A. Donenfeld <jason@zx2c4.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Jorge Lucangeli Obes <jorgelo@chromium.org>
Cc: Linus Waleij <linus.walleij@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Rapoport <mike.rapoport@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Stephen Röttger <sroettger@google.com>
Cc: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: peaktocreek

arch/arm64/Kconfig

@@ -38,6 +38,7 @@ config ARM64
 	select ARCH_HAS_KEEPINITRD
 	select ARCH_HAS_MEMBARRIER_SYNC_CORE
 	select ARCH_HAS_MEM_ENCRYPT
+	select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS
 	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
 	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 	select ARCH_HAS_NONLEAF_PMD_YOUNG if ARM64_HAFT

arch/arm64/kernel/vdso.c

@@ -130,7 +130,8 @@ static int __setup_additional_pages(enum vdso_abi abi,
 	mm->context.vdso = (void *)vdso_base;
 	ret = _install_special_mapping(mm, vdso_base, vdso_text_len,
 				       VM_READ|VM_EXEC|gp_flags|
-				       VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
+				       VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
+				       VM_SEALED_SYSMAP,
 				       vdso_info[abi].cm);
 	if (IS_ERR(ret))
 		goto up_fail;
@@ -256,7 +257,8 @@ static int aarch32_kuser_helpers_setup(struct mm_struct *mm)
 	 */
 	ret = _install_special_mapping(mm, AARCH32_VECTORS_BASE, PAGE_SIZE,
 				       VM_READ | VM_EXEC |
-				       VM_MAYREAD | VM_MAYEXEC,
+				       VM_MAYREAD | VM_MAYEXEC |
+				       VM_SEALED_SYSMAP,
 				       &aarch32_vdso_maps[AA32_MAP_VECTORS]);
 
 	return PTR_ERR_OR_ZERO(ret);
@@ -279,7 +281,8 @@ static int aarch32_sigreturn_setup(struct mm_struct *mm)
 	 */
 	ret = _install_special_mapping(mm, addr, PAGE_SIZE,
 				       VM_READ | VM_EXEC | VM_MAYREAD |
-				       VM_MAYWRITE | VM_MAYEXEC,
+				       VM_MAYWRITE | VM_MAYEXEC |
+				       VM_SEALED_SYSMAP,
 				       &aarch32_vdso_maps[AA32_MAP_SIGPAGE]);
 	if (IS_ERR(ret))
 		goto out;