diff options
| author |   Oleg Nesterov <oleg@redhat.com> | 2013-10-13 21:18:38 +0200 |
|---|---|---|
| committer | Oleg Nesterov <oleg@redhat.com> | 2013-10-29 18:02:51 +0100 |
| commit | af0d95af79773f7637107cd3871aaabcb425f15a (patch) | |
| tree | 0d71695828416dd2bf157dccd608434bdffa8bbf /kernel/events | |
| parent | uprobes: Introduce __create_xol_area() (diff) | |
| download | linux-dev-af0d95af79773f7637107cd3871aaabcb425f15a.tar.xz linux-dev-af0d95af79773f7637107cd3871aaabcb425f15a.zip | |
uprobes: Teach __create_xol_area() to accept the predefined vaddr
Currently xol_add_vma() uses get_unmapped_area() for area->vaddr,
but the next patches need to use the fixed address. So this patch
adds the new "vaddr" argument to __create_xol_area() which should
be used as area->vaddr if it is nonzero.
xol_add_vma() doesn't bother to verify that the predefined addr is
not used, insert_vm_struct() should fail if find_vma_links() detects
the overlap with the existing vma.
Also, __create_xol_area() doesn't need __GFP_ZERO to allocate area.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/events')
| -rw-r--r-- | kernel/events/uprobes.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index ad17d813e73e..7d12a45842a7 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1104,11 +1104,14 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area) if (mm->uprobes_state.xol_area) goto fail; - /* 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, @@ -1124,13 +1127,13 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area) return ret; } -static struct xol_area *__create_xol_area(void) +static struct xol_area *__create_xol_area(unsigned long vaddr) { struct mm_struct *mm = current->mm; uprobe_opcode_t insn = UPROBE_SWBP_INSN; struct xol_area *area; - area = kzalloc(sizeof(*area), GFP_KERNEL); + area = kmalloc(sizeof(*area), GFP_KERNEL); if (unlikely(!area)) goto out; @@ -1142,6 +1145,7 @@ static struct xol_area *__create_xol_area(void) if (!area->page) goto free_bitmap; + area->vaddr = vaddr; init_waitqueue_head(&area->wq); /* Reserve the 1st slot for get_trampoline_vaddr() */ set_bit(0, area->bitmap); @@ -1172,7 +1176,7 @@ static struct xol_area *get_xol_area(void) struct xol_area *area; if (!mm->uprobes_state.xol_area) - __create_xol_area(); + __create_xol_area(0); area = mm->uprobes_state.xol_area; smp_read_barrier_depends(); /* pairs with wmb in xol_add_vma() */ |