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[134.134.136.126]) by mx.google.com with ESMTPS id t10-v6si6980653pgn.667.2018.08.30.07.44.43 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 30 Aug 2018 07:44:43 -0700 (PDT) Received-SPF: pass (google.com: domain of yu-cheng.yu@intel.com designates 134.134.136.126 as permitted sender) client-ip=134.134.136.126; Authentication-Results: mx.google.com; spf=pass (google.com: domain of yu-cheng.yu@intel.com designates 134.134.136.126 as permitted sender) smtp.mailfrom=yu-cheng.yu@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 30 Aug 2018 07:44:43 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,307,1531810800"; d="scan'208";a="228910403" Received: from 2b52.sc.intel.com ([143.183.136.52]) by orsmga004.jf.intel.com with ESMTP; 30 Aug 2018 07:44:30 -0700 From: Yu-cheng Yu 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 Subject: [RFC PATCH v3 2/8] x86/cet/ibt: User-mode indirect branch tracking support Date: Thu, 30 Aug 2018 07:40:03 -0700 Message-Id: <20180830144009.3314-3-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180830144009.3314-1-yu-cheng.yu@intel.com> References: <20180830144009.3314-1-yu-cheng.yu@intel.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Add user-mode indirect branch tracking enabling/disabling and supporting routines. Signed-off-by: H.J. Lu Signed-off-by: Yu-cheng Yu --- arch/x86/include/asm/cet.h | 8 +++ arch/x86/include/asm/disabled-features.h | 8 ++- arch/x86/kernel/cet.c | 68 ++++++++++++++++++++++++ arch/x86/kernel/cpu/common.c | 20 ++++++- arch/x86/kernel/process.c | 1 + 5 files changed, 103 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/cet.h b/arch/x86/include/asm/cet.h index 212bd68e31d3..1fea93fd436a 100644 --- a/arch/x86/include/asm/cet.h +++ b/arch/x86/include/asm/cet.h @@ -12,8 +12,11 @@ struct task_struct; struct cet_status { unsigned long shstk_base; unsigned long shstk_size; + unsigned long ibt_bitmap_addr; + unsigned long ibt_bitmap_size; unsigned int locked:1; unsigned int shstk_enabled:1; + unsigned int ibt_enabled:1; }; #ifdef CONFIG_X86_INTEL_CET @@ -25,6 +28,9 @@ void cet_disable_shstk(void); void cet_disable_free_shstk(struct task_struct *p); int cet_restore_signal(unsigned long ssp); int cet_setup_signal(bool ia32, unsigned long rstor, unsigned long *new_ssp); +int cet_setup_ibt(void); +int cet_setup_ibt_bitmap(void); +void cet_disable_ibt(void); #else static inline int prctl_cet(int option, unsigned long arg2) { return 0; } static inline int cet_setup_shstk(void) { return 0; } @@ -35,6 +41,8 @@ static inline void cet_disable_free_shstk(struct task_struct *p) {} static inline int cet_restore_signal(unsigned long ssp) { return 0; } static inline int cet_setup_signal(bool ia32, unsigned long rstor, unsigned long *new_ssp) { return 0; } +static inline int cet_setup_ibt(void) { return 0; } +static inline void cet_disable_ibt(void) {} #endif #endif /* __ASSEMBLY__ */ diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h index 3624a11e5ba6..ce5bdaf0f1ff 100644 --- a/arch/x86/include/asm/disabled-features.h +++ b/arch/x86/include/asm/disabled-features.h @@ -62,6 +62,12 @@ #define DISABLE_SHSTK (1<<(X86_FEATURE_SHSTK & 31)) #endif +#ifdef CONFIG_X86_INTEL_BRANCH_TRACKING_USER +#define DISABLE_IBT 0 +#else +#define DISABLE_IBT (1<<(X86_FEATURE_IBT & 31)) +#endif + /* * Make sure to add features to the correct mask */ @@ -72,7 +78,7 @@ #define DISABLED_MASK4 (DISABLE_PCID) #define DISABLED_MASK5 0 #define DISABLED_MASK6 0 -#define DISABLED_MASK7 (DISABLE_PTI) +#define DISABLED_MASK7 (DISABLE_PTI|DISABLE_IBT) #define DISABLED_MASK8 0 #define DISABLED_MASK9 (DISABLE_MPX) #define DISABLED_MASK10 0 diff --git a/arch/x86/kernel/cet.c b/arch/x86/kernel/cet.c index 1c2689738604..071b9dd5bc5c 100644 --- a/arch/x86/kernel/cet.c +++ b/arch/x86/kernel/cet.c @@ -12,6 +12,8 @@ #include #include #include +#include +#include #include #include #include @@ -283,3 +285,69 @@ int cet_setup_signal(bool ia32, unsigned long rstor_addr, set_shstk_ptr(ssp); return 0; } + +int cet_setup_ibt(void) +{ + u64 r; + unsigned long bitmap; + unsigned long size; + + if (!cpu_feature_enabled(X86_FEATURE_IBT)) + return -EOPNOTSUPP; + + size = TASK_SIZE / PAGE_SIZE / BITS_PER_BYTE; + bitmap = do_mmap_locked(0, size, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, + VM_DONTDUMP); + + if (bitmap >= TASK_SIZE) + return -ENOMEM; + + rdmsrl(MSR_IA32_U_CET, r); + r |= (MSR_IA32_CET_ENDBR_EN | MSR_IA32_CET_NO_TRACK_EN); + wrmsrl(MSR_IA32_U_CET, r); + + current->thread.cet.ibt_bitmap_addr = bitmap; + current->thread.cet.ibt_bitmap_size = size; + current->thread.cet.ibt_enabled = 1; + return 0; +} + +int cet_setup_ibt_bitmap(void) +{ + u64 r; + unsigned long bitmap; + + if (!cpu_feature_enabled(X86_FEATURE_IBT)) + return -EOPNOTSUPP; + + /* + * Lower bits of MSR_IA32_CET_LEG_IW_EN are for IBT + * settings. Clear lower bits even bitmap is already + * page-aligned. + */ + bitmap = current->thread.cet.ibt_bitmap_addr; + bitmap &= PAGE_MASK; + + /* + * Turn on IBT legacy bitmap. + */ + rdmsrl(MSR_IA32_U_CET, r); + r |= (MSR_IA32_CET_LEG_IW_EN | bitmap); + wrmsrl(MSR_IA32_U_CET, r); + return 0; +} + +void cet_disable_ibt(void) +{ + u64 r; + + if (!cpu_feature_enabled(X86_FEATURE_IBT)) + return; + + rdmsrl(MSR_IA32_U_CET, r); + r &= ~(MSR_IA32_CET_ENDBR_EN | MSR_IA32_CET_LEG_IW_EN | + MSR_IA32_CET_NO_TRACK_EN); + wrmsrl(MSR_IA32_U_CET, r); + current->thread.cet.ibt_enabled = 0; +} diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index e7eb41830add..cd03c4db2270 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -413,7 +413,8 @@ __setup("nopku", setup_disable_pku); static __always_inline void setup_cet(struct cpuinfo_x86 *c) { - if (cpu_feature_enabled(X86_FEATURE_SHSTK)) + if (cpu_feature_enabled(X86_FEATURE_SHSTK) || + cpu_feature_enabled(X86_FEATURE_IBT)) cr4_set_bits(X86_CR4_CET); } @@ -434,6 +435,23 @@ static __init int setup_disable_shstk(char *s) __setup("no_cet_shstk", setup_disable_shstk); #endif +#ifdef CONFIG_X86_INTEL_BRANCH_TRACKING_USER +static __init int setup_disable_ibt(char *s) +{ + /* require an exact match without trailing characters */ + if (strlen(s)) + return 0; + + if (!boot_cpu_has(X86_FEATURE_IBT)) + return 1; + + setup_clear_cpu_cap(X86_FEATURE_IBT); + pr_info("x86: 'no_cet_ibt' specified, disabling Branch Tracking\n"); + return 1; +} +__setup("no_cet_ibt", setup_disable_ibt); +#endif + /* * Some CPU features depend on higher CPUID levels, which may not always * be available due to CPUID level capping or broken virtualization diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 251b8714f9a3..ac0ea9c7e89f 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -137,6 +137,7 @@ void flush_thread(void) memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array)); cet_disable_shstk(); + cet_disable_ibt(); fpu__clear(&tsk->thread.fpu); }