From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Lendacky Subject: [RFC PATCH v1 01/18] x86: Set the write-protect cache mode for AMD processors Date: Tue, 26 Apr 2016 17:56:04 -0500 Message-ID: <20160426225604.13567.55443.stgit@tlendack-t1.amdoffice.net> References: <20160426225553.13567.19459.stgit@tlendack-t1.amdoffice.net> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160426225553.13567.19459.stgit@tlendack-t1.amdoffice.net> Sender: owner-linux-mm@kvack.org To: linux-arch@vger.kernel.org, linux-efi@vger.kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, iommu@lists.linux-foundation.org Cc: Radim =?utf-8?b?S3LEjW3DocWZ?= , Arnd Bergmann , Jonathan Corbet , Matt Fleming , Joerg Roedel , Konrad Rzeszutek Wilk , Paolo Bonzini , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Andrey Ryabinin , Alexander Potapenko , Thomas Gleixner , Dmitry Vyukov List-Id: linux-efi@vger.kernel.org For AMD processors that support PAT, set the write-protect cache mode (_PAGE_CACHE_MODE_WP) entry to the actual write-protect value (x05). Signed-off-by: Tom Lendacky --- arch/x86/mm/pat.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index fb0604f..dda78ed 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -345,6 +345,8 @@ void pat_init(void) * we lose performance without causing a correctness issue. * Pentium 4 erratum N46 is an example for such an erratum, * although we try not to use PAT at all on affected CPUs. + * AMD processors support write-protect so initialize the + * PAT slot 5 appropriately. * * PTE encoding: * PAT @@ -356,7 +358,7 @@ void pat_init(void) * 010 2 UC-: _PAGE_CACHE_MODE_UC_MINUS * 011 3 UC : _PAGE_CACHE_MODE_UC * 100 4 WB : Reserved - * 101 5 WC : Reserved + * 101 5 WC : Reserved (AMD: _PAGE_CACHE_MODE_WP) * 110 6 UC-: Reserved * 111 7 WT : _PAGE_CACHE_MODE_WT * @@ -364,7 +366,12 @@ void pat_init(void) * corresponding types in the presence of PAT errata. */ pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) | - PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, WT); + PAT(4, WB) | PAT(6, UC_MINUS) | PAT(7, WT); + + if (c->x86_vendor == X86_VENDOR_AMD) + pat |= PAT(5, WP); + else + pat |= PAT(5, WC); } if (!boot_cpu_done) { -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org