Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/hch/vfs...

[pandora-kernel.git] / arch / x86 / vdso / vma.c

diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c
index 7abd2be..153407c 100644 (file)
--- a/arch/x86/vdso/vma.c
+++ b/arch/x86/vdso/vma.c
@@ -14,41 +14,61 @@
 #include <asm/vgtod.h>
 #include <asm/proto.h>
 #include <asm/vdso.h>
+#include <asm/page.h>
 
 unsigned int __read_mostly vdso_enabled = 1;
 
 extern char vdso_start[], vdso_end[];
 extern unsigned short vdso_sync_cpuid;
 
-static struct page **vdso_pages;
+extern struct page *vdso_pages[];
 static unsigned vdso_size;
 
-static int __init init_vdso_vars(void)
+static void __init patch_vdso(void *vdso, size_t len)
+{
+       Elf64_Ehdr *hdr = vdso;
+       Elf64_Shdr *sechdrs, *alt_sec = 0;
+       char *secstrings;
+       void *alt_data;
+       int i;
+
+       BUG_ON(len < sizeof(Elf64_Ehdr));
+       BUG_ON(memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0);
+
+       sechdrs = (void *)hdr + hdr->e_shoff;
+       secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+
+       for (i = 1; i < hdr->e_shnum; i++) {
+               Elf64_Shdr *shdr = &sechdrs[i];
+               if (!strcmp(secstrings + shdr->sh_name, ".altinstructions")) {
+                       alt_sec = shdr;
+                       goto found;
+               }
+       }
+
+       /* If we get here, it's probably a bug. */
+       pr_warning("patch_vdso: .altinstructions not found\n");
+       return;  /* nothing to patch */
+
+found:
+       alt_data = (void *)hdr + alt_sec->sh_offset;
+       apply_alternatives(alt_data, alt_data + alt_sec->sh_size);
+}
+
+static int __init init_vdso(void)
 {
        int npages = (vdso_end - vdso_start + PAGE_SIZE - 1) / PAGE_SIZE;
        int i;
 
+       patch_vdso(vdso_start, vdso_end - vdso_start);
+
        vdso_size = npages << PAGE_SHIFT;
-       vdso_pages = kmalloc(sizeof(struct page *) * npages, GFP_KERNEL);
-       if (!vdso_pages)
-               goto oom;
-       for (i = 0; i < npages; i++) {
-               struct page *p;
-               p = alloc_page(GFP_KERNEL);
-               if (!p)
-                       goto oom;
-               vdso_pages[i] = p;
-               copy_page(page_address(p), vdso_start + i*PAGE_SIZE);
-       }
+       for (i = 0; i < npages; i++)
+               vdso_pages[i] = virt_to_page(vdso_start + i*PAGE_SIZE);
 
        return 0;
-
- oom:
-       printk("Cannot allocate vdso\n");
-       vdso_enabled = 0;
-       return -ENOMEM;
 }
-subsys_initcall(init_vdso_vars);
+subsys_initcall(init_vdso);
 
 struct linux_binprm;
 
@@ -69,6 +89,15 @@ static unsigned long vdso_addr(unsigned long start, unsigned len)
        addr = start + (offset << PAGE_SHIFT);
        if (addr >= end)
                addr = end;
+
+       /*
+        * page-align it here so that get_unmapped_area doesn't
+        * align it wrongfully again to the next page. addr can come in 4K
+        * unaligned here as a result of stack start randomization.
+        */
+       addr = PAGE_ALIGN(addr);
+       addr = align_addr(addr, NULL, ALIGN_VDSO);
+
        return addr;
 }