arm64/vdso: use the fault callback to map vvar pages

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Currently the vdso has no awareness of time namespaces, which may
apply distinct offsets to processes in different namespaces. To handle
this within the vdso, we'll need to expose a per-namespace data page.

As a preparatory step, this patch separates the vdso data page from
the code pages, and has it faulted in via its own fault callback.
Subsquent patches will extend this to support distinct pages per time
namespace.

The vvar vma has to be installed with the VM_PFNMAP flag to handle
faults via its vma fault callback.

Signed-off-by: Andrei Vagin <avagin@gmail.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Dmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20200624083321.144975-2-avagin@gmail.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

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Andrei Vagin 2020-06-24 01:33:16 -07:00 • committed by Catalin Marinas

parent 9ebcfadb06

commit d53b5c013e

1 changed files with 15 additions and 10 deletions

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arch/arm64/kernel/vdso.c

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