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uprobes: Introduce copy_to_page()

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Extract the kmap_atomic/memcpy/kunmap_atomic code from
xol_get_insn_slot() into the new simple helper, copy_to_page().
It will have more users soon.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
This commit is contained in:
Oleg Nesterov 2013-03-24 18:58:04 +01:00
parent 98763a1bb1
commit 5669ccee21
1 changed files with 8 additions and 6 deletions
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14
kernel/events/uprobes.c
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@ -194,6 +194,13 @@ static void copy_from_page(struct page *page, unsigned long vaddr, void *dst, in
kunmap_atomic(kaddr);
}
static void copy_to_page(struct page *page, unsigned long vaddr, const void *src, int len)
{
void *kaddr = kmap_atomic(page);
memcpy(kaddr + (vaddr & ~PAGE_MASK), src, len);
kunmap_atomic(kaddr);
}
static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode)
{
uprobe_opcode_t old_opcode;
@ -1227,9 +1234,7 @@ static unsigned long xol_take_insn_slot(struct xol_area *area)
static unsigned long xol_get_insn_slot(struct uprobe *uprobe)
{
struct xol_area *area;
unsigned long offset;
unsigned long xol_vaddr;
void *vaddr;
area = get_xol_area();
if (!area)
@ -1240,10 +1245,7 @@ static unsigned long xol_get_insn_slot(struct uprobe *uprobe)
return 0;
/* Initialize the slot */
offset = xol_vaddr & ~PAGE_MASK;
vaddr = kmap_atomic(area->page);
memcpy(vaddr + offset, uprobe->arch.insn, MAX_UINSN_BYTES);
kunmap_atomic(vaddr);
copy_to_page(area->page, xol_vaddr, uprobe->arch.insn, MAX_UINSN_BYTES);
/*
* We probably need flush_icache_user_range() but it needs vma.
* This should work on supported architectures too.