From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 9CF1B6B000C for ; Tue, 10 Jul 2018 18:31:13 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id v9-v6so4865613pfn.6 for ; Tue, 10 Jul 2018 15:31:13 -0700 (PDT) Received: from mga11.intel.com (mga11.intel.com. [192.55.52.93]) by mx.google.com with ESMTPS id q185-v6si17504162pga.322.2018.07.10.15.31.12 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 10 Jul 2018 15:31:12 -0700 (PDT) From: Yu-cheng Yu Subject: [RFC PATCH v2 08/27] mm: Introduce VM_SHSTK for shadow stack memory Date: Tue, 10 Jul 2018 15:26:20 -0700 Message-Id: <20180710222639.8241-9-yu-cheng.yu@intel.com> In-Reply-To: <20180710222639.8241-1-yu-cheng.yu@intel.com> References: <20180710222639.8241-1-yu-cheng.yu@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Cyrill Gorcunov , Dave Hansen , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , "Ravi V. Shankar" , Vedvyas Shanbhogue Cc: Yu-cheng Yu VM_SHSTK indicates a shadow stack memory area. A shadow stack PTE must be read-only and dirty. For non shadow stack, we use a spare bit of the 64-bit PTE for dirty. The PTE changes are in the next patch. There is no more spare bit in the 32-bit PTE (except for PAE) and the shadow stack is not implemented for the 32-bit kernel. Signed-off-by: Yu-cheng Yu --- include/linux/mm.h | 8 ++++++++ mm/internal.h | 8 ++++++++ 2 files changed, 16 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index a0fbb9ffe380..d7b338b41593 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -222,11 +222,13 @@ extern unsigned int kobjsize(const void *objp); #define VM_HIGH_ARCH_BIT_2 34 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_BIT_3 35 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_BIT_4 36 /* bit only usable on 64-bit architectures */ +#define VM_HIGH_ARCH_BIT_5 37 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_0 BIT(VM_HIGH_ARCH_BIT_0) #define VM_HIGH_ARCH_1 BIT(VM_HIGH_ARCH_BIT_1) #define VM_HIGH_ARCH_2 BIT(VM_HIGH_ARCH_BIT_2) #define VM_HIGH_ARCH_3 BIT(VM_HIGH_ARCH_BIT_3) #define VM_HIGH_ARCH_4 BIT(VM_HIGH_ARCH_BIT_4) +#define VM_HIGH_ARCH_5 BIT(VM_HIGH_ARCH_BIT_5) #endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */ #ifdef CONFIG_ARCH_HAS_PKEYS @@ -264,6 +266,12 @@ extern unsigned int kobjsize(const void *objp); # define VM_MPX VM_NONE #endif +#ifdef CONFIG_X86_INTEL_SHADOW_STACK_USER +# define VM_SHSTK VM_HIGH_ARCH_5 +#else +# define VM_SHSTK VM_NONE +#endif + #ifndef VM_GROWSUP # define VM_GROWSUP VM_NONE #endif diff --git a/mm/internal.h b/mm/internal.h index 9e3654d70289..b09c29762d85 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -280,6 +280,14 @@ static inline bool is_data_mapping(vm_flags_t flags) return (flags & (VM_WRITE | VM_SHARED | VM_STACK)) == VM_WRITE; } +/* + * Shadow stack area + */ +static inline bool is_shstk_mapping(vm_flags_t flags) +{ + return (flags & VM_SHSTK); +} + /* mm/util.c */ void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, struct vm_area_struct *prev, struct rb_node *rb_parent); -- 2.17.1