lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-ID: <CA+CK2bC4X4SmZ4FBXSBO15ErCd3yDeU9i97mZfQWbZaXN2AWNw@mail.gmail.com> Date: Sat, 13 Feb 2021 13:17:11 -0500 From: Pavel Tatashin <pasha.tatashin@...een.com> To: Tyler Hicks <tyhicks@...ux.microsoft.com> Cc: James Morris <jmorris@...ei.org>, Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>, Andrew Morton <akpm@...ux-foundation.org>, Anshuman Khandual <anshuman.khandual@....com>, Mike Rapoport <rppt@...nel.org>, Logan Gunthorpe <logang@...tatee.com>, ardb@...nel.org, Linux ARM <linux-arm-kernel@...ts.infradead.org>, LKML <linux-kernel@...r.kernel.org> Subject: Re: [PATCH] arm64: mm: correct the start of physical address in linear map > We're ignoring the portion from the linear mapping's start PA to the > point of wraparound. Could the start and end of the hot plugged memory > fall within this range and, as a result, the hot plug operation be > incorrectly blocked? Hi Tyler, Thank you for looking at this fix. The maximum addressable PA's can be seen in this function: id_aa64mmfr0_parange_to_phys_shift(). For example for PA shift 32, the linear map must be able to cover any physical addresses from 0 to "1 << 32". Therefore, 0 to __pa(PAGE_END - 1); must include 0 to "1<<32". The randomization of the linear map tries to hide where exactly within the linear map the [0 to max_phys] addresses are located by changing PHYS_OFFSET (linear map space is usually much bigger than PA space). Therefore, the beginning or end of a linear map can actually convert to completely bagus high PA addresses, but this is normal. Thank you, Pasha > > Tyler > > > + > > /* > > * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)] > > * accommodating both its ends but excluding PAGE_END. Max physical > > * range which can be mapped inside this linear mapping range, must > > * also be derived from its end points. > > */ > > - return start >= __pa(_PAGE_OFFSET(vabits_actual)) && > > - (start + size - 1) <= __pa(PAGE_END - 1); > > + return start >= start_linear_pa && (start + size - 1) <= end_linear_pa; > > } > > > > int arch_add_memory(int nid, u64 start, u64 size, > > -- > > 2.25.1 > >
Powered by blists - more mailing lists