[PATCH] mseal sysmap: enable LoongArch

[WangYuli]

Provide support for CONFIG_MSEAL_SYSTEM_MAPPINGS on LoongArch,
covering the vdso.

Tested-by: Yuli Wang <wangyuli@xxxxxxxxxxxxx>
Signed-off-by: Yuli Wang <wangyuli@xxxxxxxxxxxxx>
---
 Documentation/userspace-api/mseal.rst | 2 +-
 arch/loongarch/Kconfig                | 1 +
 arch/loongarch/kernel/vdso.c          | 4 +++-
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/Documentation/userspace-api/mseal.rst b/Documentation/userspace-api/mseal.rst
index 1dabfc29be0d..ef733f69003d 100644
--- a/Documentation/userspace-api/mseal.rst
+++ b/Documentation/userspace-api/mseal.rst
@@ -144,7 +144,7 @@ Use cases
   architecture.
 
   The following architectures currently support this feature: x86-64, arm64,
-  and s390.
+  loongarch and s390.
 
   WARNING: This feature breaks programs which rely on relocating
   or unmapping system mappings. Known broken software at the time
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 067c0b994648..54ed5b59a690 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -69,6 +69,7 @@ config LOONGARCH
 	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
 	select ARCH_SUPPORTS_LTO_CLANG
 	select ARCH_SUPPORTS_LTO_CLANG_THIN
+	select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS
 	select ARCH_SUPPORTS_NUMA_BALANCING
 	select ARCH_SUPPORTS_RT
 	select ARCH_USE_BUILTIN_BSWAP
diff --git a/arch/loongarch/kernel/vdso.c b/arch/loongarch/kernel/vdso.c
index 10cf1608c7b3..7b888d9085a0 100644
--- a/arch/loongarch/kernel/vdso.c
+++ b/arch/loongarch/kernel/vdso.c
@@ -105,7 +105,9 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 
 	vdso_addr = data_addr + VVAR_SIZE;
 	vma = _install_special_mapping(mm, vdso_addr, info->size,
-				       VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
+				       VM_READ | VM_EXEC |
+				       VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC |
+				       VM_SEALED_SYSMAP,
 				       &info->code_mapping);
 	if (IS_ERR(vma)) {
 		ret = PTR_ERR(vma);
-- 
2.49.0