From mboxrd@z Thu Jan 1 00:00:00 1970 From: gregkh@linuxfoundation.org (Greg KH) Date: Sat, 24 Feb 2018 09:34:24 +0100 Subject: [PATCH -stable] arm64: mm: don't write garbage into TTBR1_EL1 register In-Reply-To: <20180223182902.24873-1-ard.biesheuvel@linaro.org> References: <20180223182902.24873-1-ard.biesheuvel@linaro.org> Message-ID: <20180224083424.GC9681@kroah.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Feb 23, 2018 at 06:29:02PM +0000, Ard Biesheuvel wrote: > 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: #v4.14 > Reported-by: Nicolas Dechesne > Signed-off-by: Ard Biesheuvel > --- > arch/arm64/mm/proc.S | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Any reason why you didn't cc: the stable list, as this is a patch that is not needed in mainline, right? > 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 I don't understand why this isn't also needed in Linus's tree. What commit there prevents this from being required? thanks, greg k-h