arm64: vdso: Use only one single vvar mapping

The vvar mapping is the same for all processes. Use a single mapping to
simplify the logic and align it with the other architectures.

In addition this will enable the move of the vvar handling into generic code.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Will Deacon <will@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/all/20241010-vdso-generic-base-v1-5-b64f0842d512@linutronix.de

diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 8ef20c16bc482e92de8098d55000c9999b89830e..e8ed8e5b713b525abac828b1a17ab9e6d974a3e9 100644 (file)
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -38,8 +38,6 @@ struct vdso_abi_info {
        const char *vdso_code_start;
        const char *vdso_code_end;
        unsigned long vdso_pages;
-       /* Data Mapping */
-       struct vm_special_mapping *dm;
        /* Code Mapping */
        struct vm_special_mapping *cm;
 };
@@ -112,6 +110,8 @@ struct vdso_data *arch_get_vdso_data(void *vvar_page)
        return (struct vdso_data *)(vvar_page);
 }
 
+static const struct vm_special_mapping vvar_map;
+
 /*
  * The vvar mapping contains data for a specific time namespace, so when a task
  * changes namespace we must unmap its vvar data for the old namespace.
@@ -128,12 +128,8 @@ int vdso_join_timens(struct task_struct *task, struct time_namespace *ns)
        mmap_read_lock(mm);
 
        for_each_vma(vmi, vma) {
-               if (vma_is_special_mapping(vma, vdso_info[VDSO_ABI_AA64].dm))
-                       zap_vma_pages(vma);
-#ifdef CONFIG_COMPAT_VDSO
-               if (vma_is_special_mapping(vma, vdso_info[VDSO_ABI_AA32].dm))
+               if (vma_is_special_mapping(vma, &vvar_map))
                        zap_vma_pages(vma);
-#endif
        }
 
        mmap_read_unlock(mm);
@@ -175,6 +171,11 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
        return vmf_insert_pfn(vma, vmf->address, pfn);
 }
 
+static const struct vm_special_mapping vvar_map = {
+       .name   = "[vvar]",
+       .fault = vvar_fault,
+};
+
 static int __setup_additional_pages(enum vdso_abi abi,
                                    struct mm_struct *mm,
                                    struct linux_binprm *bprm,
@@ -198,7 +199,7 @@ static int __setup_additional_pages(enum vdso_abi abi,
 
        ret = _install_special_mapping(mm, vdso_base, VVAR_NR_PAGES * PAGE_SIZE,
                                       VM_READ|VM_MAYREAD|VM_PFNMAP,
-                                      vdso_info[abi].dm);
+                                      &vvar_map);
        if (IS_ERR(ret))
                goto up_fail;
 
@@ -228,7 +229,6 @@ up_fail:
 enum aarch32_map {
        AA32_MAP_VECTORS, /* kuser helpers */
        AA32_MAP_SIGPAGE,
-       AA32_MAP_VVAR,
        AA32_MAP_VDSO,
 };
 
@@ -253,10 +253,6 @@ static struct vm_special_mapping aarch32_vdso_maps[] = {
                .pages  = &aarch32_sig_page,
                .mremap = aarch32_sigpage_mremap,
        },
-       [AA32_MAP_VVAR] = {
-               .name = "[vvar]",
-               .fault = vvar_fault,
-       },
        [AA32_MAP_VDSO] = {
                .name = "[vdso]",
                .mremap = vdso_mremap,
@@ -306,7 +302,6 @@ static int __init __aarch32_alloc_vdso_pages(void)
        if (!IS_ENABLED(CONFIG_COMPAT_VDSO))
                return 0;
 
-       vdso_info[VDSO_ABI_AA32].dm = &aarch32_vdso_maps[AA32_MAP_VVAR];
        vdso_info[VDSO_ABI_AA32].cm = &aarch32_vdso_maps[AA32_MAP_VDSO];
 
        return __vdso_init(VDSO_ABI_AA32);
@@ -401,26 +396,14 @@ out:
 }
 #endif /* CONFIG_COMPAT */
 
-enum aarch64_map {
-       AA64_MAP_VVAR,
-       AA64_MAP_VDSO,
-};
-
-static struct vm_special_mapping aarch64_vdso_maps[] __ro_after_init = {
-       [AA64_MAP_VVAR] = {
-               .name   = "[vvar]",
-               .fault = vvar_fault,
-       },
-       [AA64_MAP_VDSO] = {
-               .name   = "[vdso]",
-               .mremap = vdso_mremap,
-       },
+static struct vm_special_mapping aarch64_vdso_map __ro_after_init = {
+       .name   = "[vdso]",
+       .mremap = vdso_mremap,
 };
 
 static int __init vdso_init(void)
 {
-       vdso_info[VDSO_ABI_AA64].dm = &aarch64_vdso_maps[AA64_MAP_VVAR];
-       vdso_info[VDSO_ABI_AA64].cm = &aarch64_vdso_maps[AA64_MAP_VDSO];
+       vdso_info[VDSO_ABI_AA64].cm = &aarch64_vdso_map;
 
        return __vdso_init(VDSO_ABI_AA64);
 }