MIPS: VDSO: Always map near top of user memory

[linux-2.6-microblaze.git] / arch / mips / kernel / vdso.c

diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c
index 8f845f6..48a9c6b 100644 (file)
--- a/arch/mips/kernel/vdso.c
+++ b/arch/mips/kernel/vdso.c
@@ -15,6 +15,7 @@
 #include <linux/ioport.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
+#include <linux/random.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/timekeeper_internal.h>
@@ -97,6 +98,21 @@ void update_vsyscall_tz(void)
        }
 }
 
+static unsigned long vdso_base(void)
+{
+       unsigned long base;
+
+       /* Skip the delay slot emulation page */
+       base = STACK_TOP + PAGE_SIZE;
+
+       if (current->flags & PF_RANDOMIZE) {
+               base += get_random_int() & (VDSO_RANDOMIZE_SIZE - 1);
+               base = PAGE_ALIGN(base);
+       }
+
+       return base;
+}
+
 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 {
        struct mips_vdso_image *image = current->thread.abi->vdso;
@@ -137,7 +153,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
        if (cpu_has_dc_aliases)
                size += shm_align_mask + 1;
 
-       base = get_unmapped_area(NULL, 0, size, 0, 0);
+       base = get_unmapped_area(NULL, vdso_base(), size, 0, 0);
        if (IS_ERR_VALUE(base)) {
                ret = base;
                goto out;