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d96cc49bff
enter_lazy_tlb is called when a kernel thread rides on the back of
another mm, due to a context switch or an explicit call to unuse_mm
where a call to switch_mm is elided.
In these cases, it's important to keep the saved ttbr value up to date
with the active mm, otherwise we can end up with a stale value which
points to a potentially freed page table.
This patch implements enter_lazy_tlb for arm64, so that the saved ttbr0
is kept up-to-date with the active mm for kernel threads.
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Cc: <stable@vger.kernel.org>
Fixes: 39bc88e5e3 ("arm64: Disable TTBR0_EL1 during normal kernel execution")
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Vinayak Menon <vinmenon@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.