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charset=utf-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Michal Suchanek , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Segher Boessenkool's on February 26, 2020 7:20 am: > Hi! >=20 > On Wed, Feb 26, 2020 at 03:35:35AM +1000, Nicholas Piggin wrote: >> Kernel addresses and potentially other sensitive data could be leaked >> in volatile registers after a syscall. >=20 >> cmpdi r3,0 >> bne .Lsyscall_restore_regs >> + li r0,0 >> + li r4,0 >> + li r5,0 >> + li r6,0 >> + li r7,0 >> + li r8,0 >> + li r9,0 >> + li r10,0 >> + li r11,0 >> + li r12,0 >> + mtctr r0 >> + mtspr SPRN_XER,r0 >> .Lsyscall_restore_regs_cont: >=20 > What about LR? Is that taken care of later? LR is preserved by sc as per ABI. > This also deserves a big fat comment imo, it is very important after > all, and not so obvious. Sure I can add something. Thanks, Nick =