uprobes: Change uprobe_copy_process() to dup return_instances

[platform/adaptation/renesas_rcar/renesas_kernel.git] / kernel / events / uprobes.c

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index ad8e1bd..1c6cda6 100644 (file)
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1096,21 +1096,22 @@ void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned lon
 }
 
 /* Slot allocation for XOL */
-static int xol_add_vma(struct xol_area *area)
+static int xol_add_vma(struct mm_struct *mm, struct xol_area *area)
 {
-       struct mm_struct *mm = current->mm;
        int ret = -EALREADY;
 
        down_write(&mm->mmap_sem);
        if (mm->uprobes_state.xol_area)
                goto fail;
 
-       ret = -ENOMEM;
-       /* Try to map as high as possible, this is only a hint. */
-       area->vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, PAGE_SIZE, 0, 0);
-       if (area->vaddr & ~PAGE_MASK) {
-               ret = area->vaddr;
-               goto fail;
+       if (!area->vaddr) {
+               /* Try to map as high as possible, this is only a hint. */
+               area->vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE,
+                                               PAGE_SIZE, 0, 0);
+               if (area->vaddr & ~PAGE_MASK) {
+                       ret = area->vaddr;
+                       goto fail;
+               }
        }
 
        ret = install_special_mapping(mm, area->vaddr, PAGE_SIZE,
@@ -1120,30 +1121,19 @@ static int xol_add_vma(struct xol_area *area)
 
        smp_wmb();      /* pairs with get_xol_area() */
        mm->uprobes_state.xol_area = area;
-       ret = 0;
  fail:
        up_write(&mm->mmap_sem);
 
        return ret;
 }
 
-/*
- * get_xol_area - Allocate process's xol_area if necessary.
- * This area will be used for storing instructions for execution out of line.
- *
- * Returns the allocated area or NULL.
- */
-static struct xol_area *get_xol_area(void)
+static struct xol_area *__create_xol_area(unsigned long vaddr)
 {
        struct mm_struct *mm = current->mm;
-       struct xol_area *area;
        uprobe_opcode_t insn = UPROBE_SWBP_INSN;
+       struct xol_area *area;
 
-       area = mm->uprobes_state.xol_area;
-       if (area)
-               goto ret;
-
-       area = kzalloc(sizeof(*area), GFP_KERNEL);
+       area = kmalloc(sizeof(*area), GFP_KERNEL);
        if (unlikely(!area))
                goto out;
 
@@ -1155,13 +1145,14 @@ static struct xol_area *get_xol_area(void)
        if (!area->page)
                goto free_bitmap;
 
-       /* allocate first slot of task's xol_area for the return probes */
+       area->vaddr = vaddr;
+       init_waitqueue_head(&area->wq);
+       /* Reserve the 1st slot for get_trampoline_vaddr() */
        set_bit(0, area->bitmap);
-       copy_to_page(area->page, 0, &insn, UPROBE_SWBP_INSN_SIZE);
        atomic_set(&area->slot_count, 1);
-       init_waitqueue_head(&area->wq);
+       copy_to_page(area->page, 0, &insn, UPROBE_SWBP_INSN_SIZE);
 
-       if (!xol_add_vma(area))
+       if (!xol_add_vma(mm, area))
                return area;
 
        __free_page(area->page);
@@ -1170,9 +1161,25 @@ static struct xol_area *get_xol_area(void)
  free_area:
        kfree(area);
  out:
+       return NULL;
+}
+
+/*
+ * get_xol_area - Allocate process's xol_area if necessary.
+ * This area will be used for storing instructions for execution out of line.
+ *
+ * Returns the allocated area or NULL.
+ */
+static struct xol_area *get_xol_area(void)
+{
+       struct mm_struct *mm = current->mm;
+       struct xol_area *area;
+
+       if (!mm->uprobes_state.xol_area)
+               __create_xol_area(0);
+
        area = mm->uprobes_state.xol_area;
- ret:
-       smp_read_barrier_depends();     /* pairs with wmb in xol_add_vma() */
+       smp_read_barrier_depends();     /* pairs with wmb in xol_add_vma() */
        return area;
 }
 
@@ -1345,14 +1352,6 @@ void uprobe_free_utask(struct task_struct *t)
 }
 
 /*
- * Called in context of a new clone/fork from copy_process.
- */
-void uprobe_copy_process(struct task_struct *t)
-{
-       t->utask = NULL;
-}
-
-/*
  * Allocate a uprobe_task object for the task if if necessary.
  * Called when the thread hits a breakpoint.
  *
@@ -1367,6 +1366,57 @@ static struct uprobe_task *get_utask(void)
        return current->utask;
 }
 
+static int dup_utask(struct task_struct *t, struct uprobe_task *o_utask)
+{
+       struct uprobe_task *n_utask;
+       struct return_instance **p, *o, *n;
+
+       n_utask = kzalloc(sizeof(struct uprobe_task), GFP_KERNEL);
+       if (!n_utask)
+               return -ENOMEM;
+       t->utask = n_utask;
+
+       p = &n_utask->return_instances;
+       for (o = o_utask->return_instances; o; o = o->next) {
+               n = kmalloc(sizeof(struct return_instance), GFP_KERNEL);
+               if (!n)
+                       return -ENOMEM;
+
+               *n = *o;
+               atomic_inc(&n->uprobe->ref);
+               n->next = NULL;
+
+               *p = n;
+               p = &n->next;
+               n_utask->depth++;
+       }
+
+       return 0;
+}
+
+static void uprobe_warn(struct task_struct *t, const char *msg)
+{
+       pr_warn("uprobe: %s:%d failed to %s\n",
+                       current->comm, current->pid, msg);
+}
+
+/*
+ * Called in context of a new clone/fork from copy_process.
+ */
+void uprobe_copy_process(struct task_struct *t)
+{
+       struct uprobe_task *utask = current->utask;
+       struct mm_struct *mm = current->mm;
+
+       t->utask = NULL;
+
+       if (mm == t->mm || !utask || !utask->return_instances)
+               return;
+
+       if (dup_utask(t, utask))
+               return uprobe_warn(t, "dup ret instances");
+}
+
 /*
  * Current area->vaddr notion assume the trampoline address is always
  * equal area->vaddr.