From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f51.google.com (mail-pa0-f51.google.com [209.85.220.51]) by kanga.kvack.org (Postfix) with ESMTP id 147046B00D7 for ; Fri, 14 Nov 2014 10:18:39 -0500 (EST) Received: by mail-pa0-f51.google.com with SMTP id ey11so872321pad.38 for ; Fri, 14 Nov 2014 07:18:38 -0800 (PST) Received: from mga03.intel.com (mga03.intel.com. [134.134.136.65]) by mx.google.com with ESMTP id fs1si28686323pbd.25.2014.11.14.07.18.36 for ; Fri, 14 Nov 2014 07:18:37 -0800 (PST) Subject: [PATCH 07/11] x86, mpx: add MPX-specific mmap interface From: Dave Hansen Date: Fri, 14 Nov 2014 07:18:27 -0800 References: <20141114151816.F56A3072@viggo.jf.intel.com> In-Reply-To: <20141114151816.F56A3072@viggo.jf.intel.com> Message-Id: <20141114151827.CE440F67@viggo.jf.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: hpa@zytor.com Cc: tglx@linutronix.de, mingo@redhat.com, x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-mips@linux-mips.org, qiaowei.ren@intel.com, Dave Hansen , dave.hansen@linux.intel.com From: Dave Hansen We have chosen to perform the allocation of bounds tables in kernel (See the patch "on-demand kernel allocation of bounds tables") and to mark these VMAs with VM_MPX. However, there is currently no suitable interface to actually do this. Existing interfaces, like do_mmap_pgoff(), have no way to set a modified ->vm_ops or ->vm_flags and don't hold mmap_sem long enough to let a caller do it. This patch wraps mmap_region() and hold mmap_sem long enough to make the modifications to the VMA which we need. Also note the 32/64-bit #ifdef in the header. We actually need to do this at runtime eventually. But, for now, we don't support running 32-bit binaries on 64-bit kernels. Support for this will come in later patches. Signed-off-by: Qiaowei Ren Signed-off-by: Dave Hansen --- b/arch/x86/Kconfig | 4 ++ b/arch/x86/include/asm/mpx.h | 36 ++++++++++++++++++ b/arch/x86/mm/Makefile | 2 + b/arch/x86/mm/mpx.c | 86 +++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 128 insertions(+) diff -puN /dev/null arch/x86/include/asm/mpx.h --- /dev/null 2014-10-10 16:10:57.316716958 -0700 +++ b/arch/x86/include/asm/mpx.h 2014-11-14 07:06:23.077645424 -0800 @@ -0,0 +1,36 @@ +#ifndef _ASM_X86_MPX_H +#define _ASM_X86_MPX_H + +#include +#include + +#ifdef CONFIG_X86_64 + +/* upper 28 bits [47:20] of the virtual address in 64-bit used to + * index into bounds directory (BD). + */ +#define MPX_BD_ENTRY_OFFSET 28 +#define MPX_BD_ENTRY_SHIFT 3 +/* bits [19:3] of the virtual address in 64-bit used to index into + * bounds table (BT). + */ +#define MPX_BT_ENTRY_OFFSET 17 +#define MPX_BT_ENTRY_SHIFT 5 +#define MPX_IGN_BITS 3 + +#else + +#define MPX_BD_ENTRY_OFFSET 20 +#define MPX_BD_ENTRY_SHIFT 2 +#define MPX_BT_ENTRY_OFFSET 10 +#define MPX_BT_ENTRY_SHIFT 4 +#define MPX_IGN_BITS 2 + +#endif + +#define MPX_BD_SIZE_BYTES (1UL<<(MPX_BD_ENTRY_OFFSET+MPX_BD_ENTRY_SHIFT)) +#define MPX_BT_SIZE_BYTES (1UL<<(MPX_BT_ENTRY_OFFSET+MPX_BT_ENTRY_SHIFT)) + +#define MPX_BNDSTA_ERROR_CODE 0x3 + +#endif /* _ASM_X86_MPX_H */ diff -puN arch/x86/Kconfig~mpx-v11-add-MPX-specific-mmap-interface arch/x86/Kconfig --- a/arch/x86/Kconfig~mpx-v11-add-MPX-specific-mmap-interface 2014-11-14 07:06:23.072645199 -0800 +++ b/arch/x86/Kconfig 2014-11-14 07:06:23.078645470 -0800 @@ -244,6 +244,10 @@ config HAVE_INTEL_TXT def_bool y depends on INTEL_IOMMU && ACPI +config X86_INTEL_MPX + def_bool y + depends on CPU_SUP_INTEL + config X86_32_SMP def_bool y depends on X86_32 && SMP diff -puN arch/x86/mm/Makefile~mpx-v11-add-MPX-specific-mmap-interface arch/x86/mm/Makefile --- a/arch/x86/mm/Makefile~mpx-v11-add-MPX-specific-mmap-interface 2014-11-14 07:06:23.074645289 -0800 +++ b/arch/x86/mm/Makefile 2014-11-14 07:06:23.078645470 -0800 @@ -30,3 +30,5 @@ obj-$(CONFIG_ACPI_NUMA) += srat.o obj-$(CONFIG_NUMA_EMU) += numa_emulation.o obj-$(CONFIG_MEMTEST) += memtest.o + +obj-$(CONFIG_X86_INTEL_MPX) += mpx.o diff -puN /dev/null arch/x86/mm/mpx.c --- /dev/null 2014-10-10 16:10:57.316716958 -0700 +++ b/arch/x86/mm/mpx.c 2014-11-14 07:06:23.078645470 -0800 @@ -0,0 +1,86 @@ +/* + * mpx.c - Memory Protection eXtensions + * + * Copyright (c) 2014, Intel Corporation. + * Qiaowei Ren + * Dave Hansen + */ +#include +#include +#include + +#include +#include + +static const char *mpx_mapping_name(struct vm_area_struct *vma) +{ + return "[mpx]"; +} + +static struct vm_operations_struct mpx_vma_ops = { + .name = mpx_mapping_name, +}; + +/* + * This is really a simplified "vm_mmap". it only handles MPX + * bounds tables (the bounds directory is user-allocated). + * + * Later on, we use the vma->vm_ops to uniquely identify these + * VMAs. + */ +static unsigned long mpx_mmap(unsigned long len) +{ + unsigned long ret; + unsigned long addr, pgoff; + struct mm_struct *mm = current->mm; + vm_flags_t vm_flags; + struct vm_area_struct *vma; + + /* Only bounds table and bounds directory can be allocated here */ + if (len != MPX_BD_SIZE_BYTES && len != MPX_BT_SIZE_BYTES) + return -EINVAL; + + down_write(&mm->mmap_sem); + + /* Too many mappings? */ + if (mm->map_count > sysctl_max_map_count) { + ret = -ENOMEM; + goto out; + } + + /* Obtain the address to map to. we verify (or select) it and ensure + * that it represents a valid section of the address space. + */ + addr = get_unmapped_area(NULL, 0, len, 0, MAP_ANONYMOUS | MAP_PRIVATE); + if (addr & ~PAGE_MASK) { + ret = addr; + goto out; + } + + vm_flags = VM_READ | VM_WRITE | VM_MPX | + mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; + + /* Set pgoff according to addr for anon_vma */ + pgoff = addr >> PAGE_SHIFT; + + ret = mmap_region(NULL, addr, len, vm_flags, pgoff); + if (IS_ERR_VALUE(ret)) + goto out; + + vma = find_vma(mm, ret); + if (!vma) { + ret = -ENOMEM; + goto out; + } + vma->vm_ops = &mpx_vma_ops; + + if (vm_flags & VM_LOCKED) { + up_write(&mm->mmap_sem); + mm_populate(ret, len); + return ret; + } + +out: + up_write(&mm->mmap_sem); + return ret; +} _ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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