2 files changed, 133 insertions, 0 deletions

diff --git a/include/linux/prctl.h b/include/linux/prctl.h
index a3baeb2c2161..7ddc7f1b480f 100644
--- a/include/linux/prctl.h
+++ b/include/linux/prctl.h
@@ -102,4 +102,16 @@
 
 #define PR_MCE_KILL_GET 34
 
+/*
+ * Tune up process memory map specifics.
+ */
+#define PR_SET_MM               35
+# define PR_SET_MM_START_CODE           1
+# define PR_SET_MM_END_CODE             2
+# define PR_SET_MM_START_DATA           3
+# define PR_SET_MM_END_DATA             4
+# define PR_SET_MM_START_STACK          5
+# define PR_SET_MM_START_BRK            6
+# define PR_SET_MM_BRK                  7
+
 #endif /* _LINUX_PRCTL_H */
diff --git a/kernel/sys.c b/kernel/sys.c
index ddf8155bf3f8..40701538fbd1 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1692,6 +1692,124 @@ SYSCALL_DEFINE1(umask, int, mask)
         return mask;
 }
 
+#ifdef CONFIG_CHECKPOINT_RESTORE
+static int prctl_set_mm(int opt, unsigned long addr,
+                        unsigned long arg4, unsigned long arg5)
+{
+        unsigned long rlim = rlimit(RLIMIT_DATA);
+        unsigned long vm_req_flags;
+        unsigned long vm_bad_flags;
+        struct vm_area_struct *vma;
+        int error = 0;
+        struct mm_struct *mm = current->mm;
+
+        if (arg4 | arg5)
+                return -EINVAL;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
+        if (addr >= TASK_SIZE)
+                return -EINVAL;
+
+        down_read(&mm->mmap_sem);
+        vma = find_vma(mm, addr);
+
+        if (opt != PR_SET_MM_START_BRK && opt != PR_SET_MM_BRK) {
+                /* It must be existing VMA */
+                if (!vma || vma->vm_start > addr)
+                        goto out;
+        }
+
+        error = -EINVAL;
+        switch (opt) {
+        case PR_SET_MM_START_CODE:
+        case PR_SET_MM_END_CODE:
+                vm_req_flags = VM_READ | VM_EXEC;
+                vm_bad_flags = VM_WRITE | VM_MAYSHARE;
+
+                if ((vma->vm_flags & vm_req_flags) != vm_req_flags ||
+                    (vma->vm_flags & vm_bad_flags))
+                        goto out;
+
+                if (opt == PR_SET_MM_START_CODE)
+                        mm->start_code = addr;
+                else
+                        mm->end_code = addr;
+                break;
+
+        case PR_SET_MM_START_DATA:
+        case PR_SET_MM_END_DATA:
+                vm_req_flags = VM_READ | VM_WRITE;
+                vm_bad_flags = VM_EXEC | VM_MAYSHARE;
+
+                if ((vma->vm_flags & vm_req_flags) != vm_req_flags ||
+                    (vma->vm_flags & vm_bad_flags))
+                        goto out;
+
+                if (opt == PR_SET_MM_START_DATA)
+                        mm->start_data = addr;
+                else
+                        mm->end_data = addr;
+                break;
+
+        case PR_SET_MM_START_STACK:
+
+#ifdef CONFIG_STACK_GROWSUP
+                vm_req_flags = VM_READ | VM_WRITE | VM_GROWSUP;
+#else
+                vm_req_flags = VM_READ | VM_WRITE | VM_GROWSDOWN;
+#endif
+                if ((vma->vm_flags & vm_req_flags) != vm_req_flags)
+                        goto out;
+
+                mm->start_stack = addr;
+                break;
+
+        case PR_SET_MM_START_BRK:
+                if (addr <= mm->end_data)
+                        goto out;
+
+                if (rlim < RLIM_INFINITY &&
+                    (mm->brk - addr) +
+                    (mm->end_data - mm->start_data) > rlim)
+                        goto out;
+
+                mm->start_brk = addr;
+                break;
+
+        case PR_SET_MM_BRK:
+                if (addr <= mm->end_data)
+                        goto out;
+
+                if (rlim < RLIM_INFINITY &&
+                    (addr - mm->start_brk) +
+                    (mm->end_data - mm->start_data) > rlim)
+                        goto out;
+
+                mm->brk = addr;
+                break;
+
+        default:
+                error = -EINVAL;
+                goto out;
+        }
+
+        error = 0;
+
+out:
+        up_read(&mm->mmap_sem);
+
+        return error;
+}
+#else /* CONFIG_CHECKPOINT_RESTORE */
+static int prctl_set_mm(int opt, unsigned long addr,
+                        unsigned long arg4, unsigned long arg5)
+{
+        return -EINVAL;
+}
+#endif
+
 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
                 unsigned long, arg4, unsigned long, arg5)
 {
@@ -1841,6 +1959,9 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
                         else
                                 error = PR_MCE_KILL_DEFAULT;
                         break;
+                case PR_SET_MM:
+                        error = prctl_set_mm(arg2, arg3, arg4, arg5);
+                        break;
                 default:
                         error = -EINVAL;
                         break;