On 06/03/2016 12:50 PM, Cyrill Gorcunov wrote:
On Wed, Jun 01, 2016 at 04:11:33PM +0300, Dmitry Safonov wrote:
Make in-kernel API to map vDSO blobs on x86.
Cc: Andy Lutomirski <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Signed-off-by: Dmitry Safonov <[email protected]>
Hi! Sorry for delay in reply. Dima, here is a moment I somehow missing:
when do_map_vdso is called it is implied that old vdso is unmapped already,
or both can be present in the system?
Both can be present. There are some limitations: if first vDSO was
32-bit, syscalls through it wouldn't work, only on the last mapped.
It's because of mm->context.vdso pointer, which for 32-bit vDSO
should point on it. (and this code make it point to a new mapped vDSO)
On RFC I did patch that unmaps previous vDSO, but I have though
it's better to simplify this code and drop unmapping.
