Date: Tue, 12 Feb 2019 08:45:41 -0700 From: Khalid Aziz <khalid.aziz@...cle.com> To: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com> Cc: juergh@...il.com, tycho@...ho.ws, jsteckli@...zon.de, ak@...ux.intel.com, torvalds@...ux-foundation.org, liran.alon@...cle.com, keescook@...gle.com, Juerg Haefliger <juerg.haefliger@...onical.com>, deepa.srinivasan@...cle.com, chris.hyser@...cle.com, tyhicks@...onical.com, dwmw@...zon.co.uk, andrew.cooper3@...rix.com, jcm@...hat.com, boris.ostrovsky@...cle.com, kanth.ghatraju@...cle.com, joao.m.martins@...cle.com, jmattson@...gle.com, pradeep.vincent@...cle.com, john.haxby@...cle.com, tglx@...utronix.de, kirill.shutemov@...ux.intel.com, hch@....de, steven.sistare@...cle.com, kernel-hardening@...ts.openwall.com, linux-mm@...ck.org, linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, Tycho Andersen <tycho@...ker.com> Subject: Re: [RFC PATCH v7 05/16] arm64/mm: Add support for XPFO On 1/23/19 7:20 AM, Konrad Rzeszutek Wilk wrote: > On Thu, Jan 10, 2019 at 02:09:37PM -0700, Khalid Aziz wrote: >> From: Juerg Haefliger <juerg.haefliger@...onical.com> >> >> Enable support for eXclusive Page Frame Ownership (XPFO) for arm64 and >> provide a hook for updating a single kernel page table entry (which is >> required by the generic XPFO code). >> >> v6: use flush_tlb_kernel_range() instead of __flush_tlb_one() >> >> CC: linux-arm-kernel@...ts.infradead.org >> Signed-off-by: Juerg Haefliger <juerg.haefliger@...onical.com> >> Signed-off-by: Tycho Andersen <tycho@...ker.com> >> Signed-off-by: Khalid Aziz <khalid.aziz@...cle.com> >> --- >> arch/arm64/Kconfig | 1 + >> arch/arm64/mm/Makefile | 2 ++ >> arch/arm64/mm/xpfo.c | 58 ++++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 61 insertions(+) >> create mode 100644 arch/arm64/mm/xpfo.c >> >> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig >> index ea2ab0330e3a..f0a9c0007d23 100644 >> --- a/arch/arm64/Kconfig >> +++ b/arch/arm64/Kconfig >> @@ -171,6 +171,7 @@ config ARM64 >> select SWIOTLB >> select SYSCTL_EXCEPTION_TRACE >> select THREAD_INFO_IN_TASK >> + select ARCH_SUPPORTS_XPFO >> help >> ARM 64-bit (AArch64) Linux support. >> >> diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile >> index 849c1df3d214..cca3808d9776 100644 >> --- a/arch/arm64/mm/Makefile >> +++ b/arch/arm64/mm/Makefile >> @@ -12,3 +12,5 @@ KASAN_SANITIZE_physaddr.o += n >> >> obj-$(CONFIG_KASAN) += kasan_init.o >> KASAN_SANITIZE_kasan_init.o := n >> + >> +obj-$(CONFIG_XPFO) += xpfo.o >> diff --git a/arch/arm64/mm/xpfo.c b/arch/arm64/mm/xpfo.c >> new file mode 100644 >> index 000000000000..678e2be848eb >> --- /dev/null >> +++ b/arch/arm64/mm/xpfo.c >> @@ -0,0 +1,58 @@ >> +/* >> + * Copyright (C) 2017 Hewlett Packard Enterprise Development, L.P. >> + * Copyright (C) 2016 Brown University. All rights reserved. >> + * >> + * Authors: >> + * Juerg Haefliger <juerg.haefliger@....com> >> + * Vasileios P. Kemerlis <vpk@...brown.edu> >> + * >> + * This program is free software; you can redistribute it and/or modify it >> + * under the terms of the GNU General Public License version 2 as published by >> + * the Free Software Foundation. >> + */ >> + >> +#include <linux/mm.h> >> +#include <linux/module.h> >> + >> +#include <asm/tlbflush.h> >> + >> +/* >> + * Lookup the page table entry for a virtual address and return a pointer to >> + * the entry. Based on x86 tree. >> + */ >> +static pte_t *lookup_address(unsigned long addr) > > The x86 also has level. Would it make sense to include that in here? > Possibly. ARM64 does not define page levels (as in the enum for page levels) at this time but that can be added easily. Adding level to lookup_address() for arm will make it uniform with x86 but is there any other rationale besides that? Do you see a future use for this information? The only other architecture I could see that defines lookup_address() is sh but it uses it for trapped io only. Thanks, Khalid Download attachment "pEpkey.asc" of type "application/pgp-keys" (2461 bytes)
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