Hi Nishanth On Sat, Jan 20, 2018 at 12:10 AM, Nishanth Menon <[email protected]> wrote: > On 01/19/2018 04:21 PM, Mark Kettenis wrote: >>> >>> Date: Fri, 19 Jan 2018 16:56:14 -0500 >>> From: Tom Rini <[email protected]> >>> >>> Hey all, >>> >>> So, now that things have quieted down a little bit in this area, I've >>> been wondering about something. Over on the U-Boot side of things, are >>> there changes we need to make in order to support the kernel side of the >>> various mitigations properly? I know that for example currently >>> https://developer.arm.com/support/security-update talks about ATF >>> patches, in the context of AArch64 however. But on the other hand for >>> variant 2, there's nothing listed on the Linux side for 32bit ARM, but >>> there is for non-Linux OSes. >>> >>> And, in the event I'm also missing something else entirely that we need >>> to do here, is there something that we need to be doing? Or is it still >>> too early at this point in time to know? >> >> >> I think that for AArch32, the following bit advice is relevant: >> >> For Cortex-A15, set ACTLR[0]==1 from early initialization of the >> processor, and invalidate the branch predictor by performing an >> ICIALLU instruction. >> >> For now OpenBSD assumes that "the firmware" sets ACTLR[0] since this >> register may be read-only in non-secure mode. And unless I missed >> something Linux makes the same assumption. >> >> If U-Boot provides the PSCI implementation it should probably flush >> the BTB on affected 32-bit processors and should defenitely flush on >> 64-bit processors. > > > Seeing the traffic in kernel, I think I understand these two I know of at > least? > > A8/9/12/17: > "So without IBE set, as the comments above say, the flush won't do > anything."
Regarding IBE set, is this can be set later on boot stage after MLO? Michael > https://marc.info/?l=linux-arm-kernel&m=151566145121435&w=2 > > A15: ACTLR > https://marc.info/?l=linux-arm-kernel&m=151562519425981&w=2 > > Am I misunderstanding the list we need to do in u-boot? > > -- > Regards, > Nishanth Menon > > _______________________________________________ > U-Boot mailing list > [email protected] > https://lists.denx.de/listinfo/u-boot -- | Michael Nazzareno Trimarchi Amarula Solutions BV | | COO - Founder Cruquiuskade 47 | | +31(0)851119172 Amsterdam 1018 AM NL | | [`as] http://www.amarulasolutions.com | _______________________________________________ U-Boot mailing list [email protected] https://lists.denx.de/listinfo/u-boot
