arm64: vdso: clean up vdso_pagelist initialization

Remove some unnecessary bits that were apparently carried over from
another architecture's implementation:

- No need to get_page() the vdso text/data - these are part of the
  kernel image.
- No need for ClearPageReserved on the vdso text.
- No need to vmap the first text page to check the ELF header - this
  can be done through &vdso_start.

Also some minor cleanup:
- Use kcalloc for vdso_pagelist array allocation.
- Don't print on allocation failure, slab/slub will do that for us.

Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 12 insertions, 30 deletions

diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index a7149cae1615..50384fec56c4 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -106,49 +106,31 @@ int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
 
 static int __init vdso_init(void)
 {
-        struct page *pg;
-        char *vbase;
-        int i, ret = 0;
+        int i;
+
+        if (memcmp(&vdso_start, "\177ELF", 4)) {
+                pr_err("vDSO is not a valid ELF object!\n");
+                return -EINVAL;
+        }
 
         vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT;
         pr_info("vdso: %ld pages (%ld code, %ld data) at base %p\n",
                 vdso_pages + 1, vdso_pages, 1L, &vdso_start);
 
         /* Allocate the vDSO pagelist, plus a page for the data. */
-        vdso_pagelist = kzalloc(sizeof(struct page *) * (vdso_pages + 1),
+        vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *),
                                 GFP_KERNEL);
-        if (vdso_pagelist == NULL) {
-                pr_err("Failed to allocate vDSO pagelist!\n");
+        if (vdso_pagelist == NULL)
                 return -ENOMEM;
-        }
 
         /* Grab the vDSO code pages. */
-        for (i = 0; i < vdso_pages; i++) {
-                pg = virt_to_page(&vdso_start + i*PAGE_SIZE);
-                ClearPageReserved(pg);
-                get_page(pg);
-                vdso_pagelist[i] = pg;
-        }
-
-        /* Sanity check the shared object header. */
-        vbase = vmap(vdso_pagelist, 1, 0, PAGE_KERNEL);
-        if (vbase == NULL) {
-                pr_err("Failed to map vDSO pagelist!\n");
-                return -ENOMEM;
-        } else if (memcmp(vbase, "\177ELF", 4)) {
-                pr_err("vDSO is not a valid ELF object!\n");
-                ret = -EINVAL;
-                goto unmap;
-        }
+        for (i = 0; i < vdso_pages; i++)
+                vdso_pagelist[i] = virt_to_page(&vdso_start + i * PAGE_SIZE);
 
         /* Grab the vDSO data page. */
-        pg = virt_to_page(vdso_data);
-        get_page(pg);
-        vdso_pagelist[i] = pg;
+        vdso_pagelist[i] = virt_to_page(vdso_data);
 
-unmap:
-        vunmap(vbase);
-        return ret;
+        return 0;
 }
 arch_initcall(vdso_init);