arm64: vdso: move to _install_special_mapping and remove arch_vma_name

_install_special_mapping replaces install_special_mapping and removes
the need to detect special VMA in arch_vma_name.

This patch moves the vdso and compat vectors page code over to the new
API.

Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 35 insertions, 45 deletions

diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 84cafbc3eb54..60ae12087d9f 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -88,22 +88,29 @@ int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
 {
         struct mm_struct *mm = current->mm;
         unsigned long addr = AARCH32_VECTORS_BASE;
-        int ret;
+        static struct vm_special_mapping spec = {
+                .name   = "[vectors]",
+                .pages  = vectors_page,
+
+        };
+        void *ret;
 
         down_write(&mm->mmap_sem);
         current->mm->context.vdso = (void *)addr;
 
         /* Map vectors page at the high address. */
-        ret = install_special_mapping(mm, addr, PAGE_SIZE,
-                                      VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC,
-                                      vectors_page);
+        ret = _install_special_mapping(mm, addr, PAGE_SIZE,
+                                       VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC,
+                                       &spec);
 
         up_write(&mm->mmap_sem);
 
-        return ret;
+        return PTR_ERR_OR_ZERO(ret);
 }
 #endif /* CONFIG_COMPAT */
 
+static struct vm_special_mapping vdso_spec[2];
+
 static int __init vdso_init(void)
 {
         int i;
@@ -130,6 +137,17 @@ static int __init vdso_init(void)
         /* Grab the vDSO data page. */
         vdso_pagelist[i] = virt_to_page(vdso_data);
 
+        /* Populate the special mapping structures */
+        vdso_spec[0] = (struct vm_special_mapping) {
+                .name   = "[vdso]",
+                .pages  = vdso_pagelist,
+        };
+
+        vdso_spec[1] = (struct vm_special_mapping) {
+                .name   = "[vvar]",
+                .pages  = vdso_pagelist + vdso_pages,
+        };
+
         return 0;
 }
 arch_initcall(vdso_init);
@@ -139,7 +157,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,
 {
         struct mm_struct *mm = current->mm;
         unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
-        int ret;
+        void *ret;
 
         vdso_text_len = vdso_pages << PAGE_SHIFT;
         /* Be sure to map the data page */
@@ -148,23 +166,23 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,
         down_write(&mm->mmap_sem);
         vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0);
         if (IS_ERR_VALUE(vdso_base)) {
-                ret = vdso_base;
+                ret = ERR_PTR(vdso_base);
                 goto up_fail;
         }
         mm->context.vdso = (void *)vdso_base;
 
-        ret = install_special_mapping(mm, vdso_base, vdso_text_len,
-                                      VM_READ|VM_EXEC|
-                                      VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
-                                      vdso_pagelist);
-        if (ret)
+        ret = _install_special_mapping(mm, vdso_base, vdso_text_len,
+                                       VM_READ|VM_EXEC|
+                                       VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
+                                       &vdso_spec[0]);
+        if (IS_ERR(ret))
                 goto up_fail;
 
         vdso_base += vdso_text_len;
-        ret = install_special_mapping(mm, vdso_base, PAGE_SIZE,
-                                      VM_READ|VM_MAYREAD,
-                                      vdso_pagelist + vdso_pages);
-        if (ret)
+        ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE,
+                                       VM_READ|VM_MAYREAD,
+                                       &vdso_spec[1]);
+        if (IS_ERR(ret))
                 goto up_fail;
 
         up_write(&mm->mmap_sem);
@@ -173,35 +191,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,
 up_fail:
         mm->context.vdso = NULL;
         up_write(&mm->mmap_sem);
-        return ret;
-}
-
-const char *arch_vma_name(struct vm_area_struct *vma)
-{
-        unsigned long vdso_text;
-
-        if (!vma->vm_mm)
-                return NULL;
-
-        vdso_text = (unsigned long)vma->vm_mm->context.vdso;
-
-        /*
-         * We can re-use the vdso pointer in mm_context_t for identifying
-         * the vectors page for compat applications. The vDSO will always
-         * sit above TASK_UNMAPPED_BASE and so we don't need to worry about
-         * it conflicting with the vectors base.
-         */
-        if (vma->vm_start == vdso_text) {
-#ifdef CONFIG_COMPAT
-                if (vma->vm_start == AARCH32_VECTORS_BASE)
-                        return "[vectors]";
-#endif
-                return "[vdso]";
-        } else if (vma->vm_start == (vdso_text + (vdso_pages << PAGE_SHIFT))) {
-                return "[vvar]";
-        }
-
-        return NULL;
+        return PTR_ERR(ret);
 }
 
 /*