This is a note to let you know that I've just added the patch titled

arm64: mm: don't write garbage into TTBR1_EL1 register

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: arm64-mm-don-t-write-garbage-into-ttbr1_el1-register.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From ard.biesheuvel@linaro.org Mon Feb 26 13:53:22 2018

From: Ard Biesheuvel ard.biesheuvel@linaro.org Date: Fri, 23 Feb 2018 18:29:02 +0000 Subject: arm64: mm: don't write garbage into TTBR1_EL1 register To: linux-arm-kernel@lists.infradead.org Cc: catalin.marinas@arm.com, will.deacon@arm.com, marc.zyngier@arm.com, mark.rutland@arm.com, nicolas.dechesne@linaro.org, gregkh@linuxfoundation.org, Ard Biesheuvel ard.biesheuvel@linaro.org Message-ID: 20180223182902.24873-1-ard.biesheuvel@linaro.org

From: Ard Biesheuvel ard.biesheuvel@linaro.org

Stable backport commit 173358a49173 ("arm64: kpti: Add ->enable callback to remap swapper using nG mappings") of upstream commit f992b4dfd58b did not survive the backporting process unscathed, and ends up writing garbage into the TTBR1_EL1 register, rather than pointing it to the zero page to disable translations. Fix that.

Cc: stable@vger.kernel.org #v4.14 Reported-by: Nicolas Dechesne nicolas.dechesne@linaro.org Signed-off-by: Ard Biesheuvel ard.biesheuvel@linaro.org Acked-by: Will Deacon will.deacon@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/mm/proc.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index 08572f95bd8a..2b473ddeb7a3 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -155,7 +155,7 @@ ENDPROC(cpu_do_switch_mm)

.macro __idmap_cpu_set_reserved_ttbr1, tmp1, tmp2 adrp \tmp1, empty_zero_page - msr ttbr1_el1, \tmp2 + msr ttbr1_el1, \tmp1 isb tlbi vmalle1 dsb nsh