Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965822AbaFRJtf (ORCPT ); Wed, 18 Jun 2014 05:49:35 -0400 Received: from mga02.intel.com ([134.134.136.20]:24728 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965855AbaFRJsR (ORCPT ); Wed, 18 Jun 2014 05:48:17 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.01,499,1400050800"; d="scan'208";a="530353889" From: Qiaowei Ren To: "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , Dave Hansen Cc: x86@kernel.org, linux-kernel@vger.kernel.org, Qiaowei Ren Subject: [PATCH v6 08/10] x86, mpx: add prctl commands PR_MPX_REGISTER, PR_MPX_UNREGISTER Date: Wed, 18 Jun 2014 17:44:14 +0800 Message-Id: <1403084656-27284-9-git-send-email-qiaowei.ren@intel.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1403084656-27284-1-git-send-email-qiaowei.ren@intel.com> References: <1403084656-27284-1-git-send-email-qiaowei.ren@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch adds the PR_MPX_REGISTER and PR_MPX_UNREGISTER prctl() commands. These commands can be used to register and unregister MPX related resource on the x86 platform. The base of the bounds directory is set into mm_struct during PR_MPX_REGISTER command execution. This member can be used to check whether one application is mpx enabled. Signed-off-by: Qiaowei Ren --- arch/x86/include/asm/mpx.h | 1 + arch/x86/include/asm/processor.h | 18 ++++++++++++ arch/x86/kernel/mpx.c | 56 ++++++++++++++++++++++++++++++++++++++ include/linux/mm_types.h | 3 ++ include/uapi/linux/prctl.h | 6 ++++ kernel/sys.c | 12 ++++++++ 6 files changed, 96 insertions(+), 0 deletions(-) diff --git a/arch/x86/include/asm/mpx.h b/arch/x86/include/asm/mpx.h index 780af63..6cb0853 100644 --- a/arch/x86/include/asm/mpx.h +++ b/arch/x86/include/asm/mpx.h @@ -43,6 +43,7 @@ #define MPX_BT_SIZE_BYTES (1UL<<(MPX_BT_ENTRY_OFFSET+MPX_BT_ENTRY_SHIFT)) #define MPX_BNDSTA_ERROR_CODE 0x3 +#define MPX_BNDCFG_ENABLE_FLAG 0x1 #define MPX_BD_ENTRY_VALID_FLAG 0x1 struct mpx_insn { diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index a4ea023..6e0966e 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -952,6 +952,24 @@ extern void start_thread(struct pt_regs *regs, unsigned long new_ip, extern int get_tsc_mode(unsigned long adr); extern int set_tsc_mode(unsigned int val); +/* Register/unregister a process' MPX related resource */ +#define MPX_REGISTER(tsk) mpx_register((tsk)) +#define MPX_UNREGISTER(tsk) mpx_unregister((tsk)) + +#ifdef CONFIG_X86_INTEL_MPX +extern int mpx_register(struct task_struct *tsk); +extern int mpx_unregister(struct task_struct *tsk); +#else +static inline int mpx_register(struct task_struct *tsk) +{ + return -EINVAL; +} +static inline int mpx_unregister(struct task_struct *tsk) +{ + return -EINVAL; +} +#endif /* CONFIG_X86_INTEL_MPX */ + extern u16 amd_get_nb_id(int cpu); static inline uint32_t hypervisor_cpuid_base(const char *sig, uint32_t leaves) diff --git a/arch/x86/kernel/mpx.c b/arch/x86/kernel/mpx.c index 650b282..d8a2a09 100644 --- a/arch/x86/kernel/mpx.c +++ b/arch/x86/kernel/mpx.c @@ -1,6 +1,62 @@ #include #include +#include #include +#include +#include + +/* + * This should only be called when cpuid has been checked + * and we are sure that MPX is available. + */ +static __user void *task_get_bounds_dir(struct task_struct *tsk) +{ + struct xsave_struct *xsave_buf; + + fpu_xsave(&tsk->thread.fpu); + xsave_buf = &(tsk->thread.fpu.state->xsave); + if (!(xsave_buf->bndcsr.cfg_reg_u & MPX_BNDCFG_ENABLE_FLAG)) + return NULL; + + return (void __user *)(xsave_buf->bndcsr.cfg_reg_u & + MPX_BNDCFG_ADDR_MASK); +} + +int mpx_register(struct task_struct *tsk) +{ + struct mm_struct *mm = tsk->mm; + + if (!cpu_has_mpx) + return -EINVAL; + + /* + * runtime in the userspace will be responsible for allocation of + * the bounds directory. Then, it will save the base of the bounds + * directory into XSAVE/XRSTOR Save Area and enable MPX through + * XRSTOR instruction. + * + * fpu_xsave() is expected to be very expensive. In order to do + * performance optimization, here we get the base of the bounds + * directory and then save it into mm_struct to be used in future. + */ + mm->bd_addr = task_get_bounds_dir(tsk); + if (!mm->bd_addr) + return -EINVAL; + + pr_debug("MPX BD base address %p\n", mm->bd_addr); + return 0; +} + +int mpx_unregister(struct task_struct *tsk) +{ + struct mm_struct *mm = current->mm; + + if (!cpu_has_mpx) + return -EINVAL; + + mm->bd_addr = NULL; + return 0; +} typedef enum {REG_TYPE_RM, REG_TYPE_INDEX, REG_TYPE_BASE} reg_type_t; static unsigned long get_reg(struct mpx_insn *insn, struct pt_regs *regs, diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 8967e20..54b8011 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -454,6 +454,9 @@ struct mm_struct { bool tlb_flush_pending; #endif struct uprobes_state uprobes_state; +#ifdef CONFIG_X86_INTEL_MPX + void __user *bd_addr; /* address of the bounds directory */ +#endif }; static inline void mm_init_cpumask(struct mm_struct *mm) diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 58afc04..ce86fa9 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -152,4 +152,10 @@ #define PR_SET_THP_DISABLE 41 #define PR_GET_THP_DISABLE 42 +/* + * Register/unregister MPX related resource. + */ +#define PR_MPX_REGISTER 43 +#define PR_MPX_UNREGISTER 44 + #endif /* _LINUX_PRCTL_H */ diff --git a/kernel/sys.c b/kernel/sys.c index fba0f29..ed1a03c 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -91,6 +91,12 @@ #ifndef SET_TSC_CTL # define SET_TSC_CTL(a) (-EINVAL) #endif +#ifndef MPX_REGISTER +# define MPX_REGISTER(a) (-EINVAL) +#endif +#ifndef MPX_UNREGISTER +# define MPX_UNREGISTER(a) (-EINVAL) +#endif /* * this is where the system-wide overflow UID and GID are defined, for @@ -2011,6 +2017,12 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, me->mm->def_flags &= ~VM_NOHUGEPAGE; up_write(&me->mm->mmap_sem); break; + case PR_MPX_REGISTER: + error = MPX_REGISTER(me); + break; + case PR_MPX_UNREGISTER: + error = MPX_UNREGISTER(me); + break; default: error = -EINVAL; break; -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/