]> git.baikalelectronics.ru Git - kernel.git/commit
arm64/vdso: Support mremap() for vDSO
authorDmitry Safonov <dsafonov@virtuozzo.com>
Wed, 26 Jul 2017 17:07:37 +0000 (20:07 +0300)
committerCatalin Marinas <catalin.marinas@arm.com>
Wed, 9 Aug 2017 11:16:28 +0000 (12:16 +0100)
commita210f642592ce2a67b356953ca3993e90a00c39a
treec169ef82d580fe74b081bdae45fbc49a2b668d50
parentfed3b4b8a03fab1ec02675f6c076eaf6ae8e61f0
arm64/vdso: Support mremap() for vDSO

vDSO VMA address is saved in mm_context for the purpose of using
restorer from vDSO page to return to userspace after signal handling.

In Checkpoint Restore in Userspace (CRIU) project we place vDSO VMA
on restore back to the place where it was on the dump.
With the exception for x86 (where there is API to map vDSO with
arch_prctl()), we move vDSO inherited from CRIU task to restoree
position by mremap().

CRIU does support arm64 architecture, but kernel doesn't update
context.vdso pointer after mremap(). Which results in translation
fault after signal handling on restored application:
https://github.com/xemul/criu/issues/288

Make vDSO code track the VMA address by supplying .mremap() fops
the same way it's done for x86 and arm32 by:
commit 6eb1736a6083 ("x86/vdso: Add mremap hook to vm_special_mapping")
commit d486fb58fdce ("ARM: 8683/1: ARM32: Support mremap() for sigpage/vDSO").

Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: Christopher Covington <cov@codeaurora.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
arch/arm64/kernel/vdso.c