x86/mpx: remove MPX from arch/x86

From: Dave Hansen <dave.hansen@linux.intel.com>

MPX is being removed from the kernel due to a lack of support
in the toolchain going forward (gcc).

This removes all the remaining (dead at this point) MPX handling
code remaining in the tree.  The only remaining code is the XSAVE
support for MPX state which is currently needd for KVM to handle
VMs which might use MPX.

Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: x86@kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>

14 files changed, 1 insertions, 1315 deletions

diff --git a/arch/x86/include/asm/bugs.h b/arch/x86/include/asm/bugs.h
index 794eb2129bc6..92ae28389940 100644
--- a/arch/x86/include/asm/bugs.h
+++ b/arch/x86/include/asm/bugs.h
@@ -6,12 +6,6 @@
 
 extern void check_bugs(void);
 
-#if defined(CONFIG_CPU_SUP_INTEL)
-void check_mpx_erratum(struct cpuinfo_x86 *c);
-#else
-static inline void check_mpx_erratum(struct cpuinfo_x86 *c) {}
-#endif
-
 #if defined(CONFIG_CPU_SUP_INTEL) && defined(CONFIG_X86_32)
 int ppro_with_ram_bug(void);
 #else
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index a5ea841cc6d2..41d069fa8f2f 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -10,12 +10,6 @@
  * cpu_feature_enabled().
  */
 
-#ifdef CONFIG_X86_INTEL_MPX
-# define DISABLE_MPX	0
-#else
-# define DISABLE_MPX	(1<<(X86_FEATURE_MPX & 31))
-#endif
-
 #ifdef CONFIG_X86_SMAP
 # define DISABLE_SMAP	0
 #else
@@ -74,7 +68,7 @@
 #define DISABLED_MASK6	0
 #define DISABLED_MASK7	(DISABLE_PTI)
 #define DISABLED_MASK8	0
-#define DISABLED_MASK9	(DISABLE_MPX|DISABLE_SMAP)
+#define DISABLED_MASK9	(DISABLE_SMAP)
 #define DISABLED_MASK10	0
 #define DISABLED_MASK11	0
 #define DISABLED_MASK12	0
diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h
index e78c7db87801..bdeae9291e5c 100644
--- a/arch/x86/include/asm/mmu.h
+++ b/arch/x86/include/asm/mmu.h
@@ -50,10 +50,6 @@ typedef struct {
 	u16 pkey_allocation_map;
 	s16 execute_only_pkey;
 #endif
-#ifdef CONFIG_X86_INTEL_MPX
-	/* address of the bounds directory */
-	void __user *bd_addr;
-#endif
 } mm_context_t;
 
 #define INIT_MM_CONTEXT(mm)						\
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index b7135e92e571..a3e1c72a3ab9 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -12,7 +12,6 @@
 #include <asm/pgalloc.h>
 #include <asm/tlbflush.h>
 #include <asm/paravirt.h>
-#include <asm/mpx.h>
 #include <asm/debugreg.h>
 
 extern atomic64_t last_mm_ctx_id;
@@ -275,25 +274,6 @@ static inline bool is_64bit_mm(struct mm_struct *mm)
 static inline void arch_unmap(struct mm_struct *mm, unsigned long start,
 			      unsigned long end)
 {
-	/*
-	 * mpx_notify_unmap() goes and reads a rarely-hot
-	 * cacheline in the mm_struct.  That can be expensive
-	 * enough to be seen in profiles.
-	 *
-	 * The mpx_notify_unmap() call and its contents have been
-	 * observed to affect munmap() performance on hardware
-	 * where MPX is not present.
-	 *
-	 * The unlikely() optimizes for the fast case: no MPX
-	 * in the CPU, or no MPX use in the process.  Even if
-	 * we get this wrong (in the unlikely event that MPX
-	 * is widely enabled on some system) the overhead of
-	 * MPX itself (reading bounds tables) is expected to
-	 * overwhelm the overhead of getting this unlikely()
-	 * consistently wrong.
-	 */
-	if (unlikely(cpu_feature_enabled(X86_FEATURE_MPX)))
-		mpx_notify_unmap(mm, start, end);
 }
 
 /*
diff --git a/arch/x86/include/asm/mpx.h b/arch/x86/include/asm/mpx.h
deleted file mode 100644
index 143a5c193ed3..000000000000
--- a/arch/x86/include/asm/mpx.h
+++ /dev/null
@@ -1,116 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_X86_MPX_H
-#define _ASM_X86_MPX_H
-
-#include <linux/types.h>
-#include <linux/mm_types.h>
-
-#include <asm/ptrace.h>
-#include <asm/insn.h>
-
-/*
- * NULL is theoretically a valid place to put the bounds
- * directory, so point this at an invalid address.
- */
-#define MPX_INVALID_BOUNDS_DIR	((void __user *)-1)
-#define MPX_BNDCFG_ENABLE_FLAG	0x1
-#define MPX_BD_ENTRY_VALID_FLAG	0x1
-
-/*
- * The upper 28 bits [47:20] of the virtual address in 64-bit
- * are used to index into bounds directory (BD).
- *
- * The directory is 2G (2^31) in size, and with 8-byte entries
- * it has 2^28 entries.
- */
-#define MPX_BD_SIZE_BYTES_64	(1UL<<31)
-#define MPX_BD_ENTRY_BYTES_64	8
-#define MPX_BD_NR_ENTRIES_64	(MPX_BD_SIZE_BYTES_64/MPX_BD_ENTRY_BYTES_64)
-
-/*
- * The 32-bit directory is 4MB (2^22) in size, and with 4-byte
- * entries it has 2^20 entries.
- */
-#define MPX_BD_SIZE_BYTES_32	(1UL<<22)
-#define MPX_BD_ENTRY_BYTES_32	4
-#define MPX_BD_NR_ENTRIES_32	(MPX_BD_SIZE_BYTES_32/MPX_BD_ENTRY_BYTES_32)
-
-/*
- * A 64-bit table is 4MB total in size, and an entry is
- * 4 64-bit pointers in size.
- */
-#define MPX_BT_SIZE_BYTES_64	(1UL<<22)
-#define MPX_BT_ENTRY_BYTES_64	32
-#define MPX_BT_NR_ENTRIES_64	(MPX_BT_SIZE_BYTES_64/MPX_BT_ENTRY_BYTES_64)
-
-/*
- * A 32-bit table is 16kB total in size, and an entry is
- * 4 32-bit pointers in size.
- */
-#define MPX_BT_SIZE_BYTES_32	(1UL<<14)
-#define MPX_BT_ENTRY_BYTES_32	16
-#define MPX_BT_NR_ENTRIES_32	(MPX_BT_SIZE_BYTES_32/MPX_BT_ENTRY_BYTES_32)
-
-#define MPX_BNDSTA_TAIL		2
-#define MPX_BNDCFG_TAIL		12
-#define MPX_BNDSTA_ADDR_MASK	(~((1UL<<MPX_BNDSTA_TAIL)-1))
-#define MPX_BNDCFG_ADDR_MASK	(~((1UL<<MPX_BNDCFG_TAIL)-1))
-#define MPX_BNDSTA_ERROR_CODE	0x3
-
-struct mpx_fault_info {
-	void __user *addr;
-	void __user *lower;
-	void __user *upper;
-};
-
-#ifdef CONFIG_X86_INTEL_MPX
-
-extern int mpx_fault_info(struct mpx_fault_info *info, struct pt_regs *regs);
-extern int mpx_handle_bd_fault(void);
-
-static inline int kernel_managing_mpx_tables(struct mm_struct *mm)
-{
-	return (mm->context.bd_addr != MPX_INVALID_BOUNDS_DIR);
-}
-
-static inline void mpx_mm_init(struct mm_struct *mm)
-{
-	/*
-	 * NULL is theoretically a valid place to put the bounds
-	 * directory, so point this at an invalid address.
-	 */
-	mm->context.bd_addr = MPX_INVALID_BOUNDS_DIR;
-}
-
-extern void mpx_notify_unmap(struct mm_struct *mm, unsigned long start, unsigned long end);
-extern unsigned long mpx_unmapped_area_check(unsigned long addr, unsigned long len, unsigned long flags);
-
-#else
-static inline int mpx_fault_info(struct mpx_fault_info *info, struct pt_regs *regs)
-{
-	return -EINVAL;
-}
-static inline int mpx_handle_bd_fault(void)
-{
-	return -EINVAL;
-}
-static inline int kernel_managing_mpx_tables(struct mm_struct *mm)
-{
-	return 0;
-}
-static inline void mpx_mm_init(struct mm_struct *mm)
-{
-}
-static inline void mpx_notify_unmap(struct mm_struct *mm,
-				    unsigned long start, unsigned long end)
-{
-}
-
-static inline unsigned long mpx_unmapped_area_check(unsigned long addr,
-		unsigned long len, unsigned long flags)
-{
-	return addr;
-}
-#endif /* CONFIG_X86_INTEL_MPX */
-
-#endif /* _ASM_X86_MPX_H */
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 54f5d54280f6..4482f14dc48d 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -915,24 +915,6 @@ extern int set_tsc_mode(unsigned int val);
 
 DECLARE_PER_CPU(u64, msr_misc_features_shadow);
 
-/* Register/unregister a process' MPX related resource */
-#define MPX_ENABLE_MANAGEMENT()	mpx_enable_management()
-#define MPX_DISABLE_MANAGEMENT()	mpx_disable_management()
-
-#ifdef CONFIG_X86_INTEL_MPX
-extern int mpx_enable_management(void);
-extern int mpx_disable_management(void);
-#else
-static inline int mpx_enable_management(void)
-{
-	return -EINVAL;
-}
-static inline int mpx_disable_management(void)
-{
-	return -EINVAL;
-}
-#endif /* CONFIG_X86_INTEL_MPX */
-
 #ifdef CONFIG_CPU_SUP_AMD
 extern u16 amd_get_nb_id(int cpu);
 extern u32 amd_get_nodes_per_socket(void);
diff --git a/arch/x86/include/asm/trace/mpx.h b/arch/x86/include/asm/trace/mpx.h
deleted file mode 100644
index 54133017267c..000000000000
--- a/arch/x86/include/asm/trace/mpx.h
+++ /dev/null
@@ -1,134 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#undef TRACE_SYSTEM
-#define TRACE_SYSTEM mpx
-
-#if !defined(_TRACE_MPX_H) || defined(TRACE_HEADER_MULTI_READ)
-#define _TRACE_MPX_H
-
-#include <linux/tracepoint.h>
-
-#ifdef CONFIG_X86_INTEL_MPX
-
-TRACE_EVENT(mpx_bounds_register_exception,
-
-	TP_PROTO(void __user *addr_referenced,
-		 const struct mpx_bndreg *bndreg),
-	TP_ARGS(addr_referenced, bndreg),
-
-	TP_STRUCT__entry(
-		__field(void __user *, addr_referenced)
-		__field(u64, lower_bound)
-		__field(u64, upper_bound)
-	),
-
-	TP_fast_assign(
-		__entry->addr_referenced = addr_referenced;
-		__entry->lower_bound = bndreg->lower_bound;
-		__entry->upper_bound = bndreg->upper_bound;
-	),
-	/*
-	 * Note that we are printing out the '~' of the upper
-	 * bounds register here.  It is actually stored in its
-	 * one's complement form so that its 'init' state
-	 * corresponds to all 0's.  But, that looks like
-	 * gibberish when printed out, so print out the 1's
-	 * complement instead of the actual value here.  Note
-	 * though that you still need to specify filters for the
-	 * actual value, not the displayed one.
-	 */
-	TP_printk("address referenced: 0x%p bounds: lower: 0x%llx ~upper: 0x%llx",
-		__entry->addr_referenced,
-		__entry->lower_bound,
-		~__entry->upper_bound
-	)
-);
-
-TRACE_EVENT(bounds_exception_mpx,
-
-	TP_PROTO(const struct mpx_bndcsr *bndcsr),
-	TP_ARGS(bndcsr),
-
-	TP_STRUCT__entry(
-		__field(u64, bndcfgu)
-		__field(u64, bndstatus)
-	),
-
-	TP_fast_assign(
-		/* need to get rid of the 'const' on bndcsr */
-		__entry->bndcfgu   = (u64)bndcsr->bndcfgu;
-		__entry->bndstatus = (u64)bndcsr->bndstatus;
-	),
-
-	TP_printk("bndcfgu:0x%llx bndstatus:0x%llx",
-		__entry->bndcfgu,
-		__entry->bndstatus)
-);
-
-DECLARE_EVENT_CLASS(mpx_range_trace,
-
-	TP_PROTO(unsigned long start,
-		 unsigned long end),
-	TP_ARGS(start, end),
-
-	TP_STRUCT__entry(
-		__field(unsigned long, start)
-		__field(unsigned long, end)
-	),
-
-	TP_fast_assign(
-		__entry->start = start;
-		__entry->end   = end;
-	),
-
-	TP_printk("[0x%p:0x%p]",
-		(void *)__entry->start,
-		(void *)__entry->end
-	)
-);
-
-DEFINE_EVENT(mpx_range_trace, mpx_unmap_zap,
-	TP_PROTO(unsigned long start, unsigned long end),
-	TP_ARGS(start, end)
-);
-
-DEFINE_EVENT(mpx_range_trace, mpx_unmap_search,
-	TP_PROTO(unsigned long start, unsigned long end),
-	TP_ARGS(start, end)
-);
-
-TRACE_EVENT(mpx_new_bounds_table,
-
-	TP_PROTO(unsigned long table_vaddr),
-	TP_ARGS(table_vaddr),
-
-	TP_STRUCT__entry(
-		__field(unsigned long, table_vaddr)
-	),
-
-	TP_fast_assign(
-		__entry->table_vaddr = table_vaddr;
-	),
-
-	TP_printk("table vaddr:%p", (void *)__entry->table_vaddr)
-);
-
-#else
-
-/*
- * This gets used outside of MPX-specific code, so we need a stub.
- */
-static inline
-void trace_bounds_exception_mpx(const struct mpx_bndcsr *bndcsr)
-{
-}
-
-#endif /* CONFIG_X86_INTEL_MPX */
-
-#undef TRACE_INCLUDE_PATH
-#define TRACE_INCLUDE_PATH asm/trace/
-#undef TRACE_INCLUDE_FILE
-#define TRACE_INCLUDE_FILE mpx
-#endif /* _TRACE_MPX_H */
-
-/* This part must be outside protection */
-#include <trace/define_trace.h>
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index fffe21945374..be2c85bf9c56 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -165,22 +165,6 @@ DEFINE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page) = { .gdt = {
 } };
 EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
 
-static int __init x86_mpx_setup(char *s)
-{
-	/* require an exact match without trailing characters */
-	if (strlen(s))
-		return 0;
-
-	/* do not emit a message if the feature is not present */
-	if (!boot_cpu_has(X86_FEATURE_MPX))
-		return 1;
-
-	setup_clear_cpu_cap(X86_FEATURE_MPX);
-	pr_info("nompx: Intel Memory Protection Extensions (MPX) disabled\n");
-	return 1;
-}
-__setup("nompx", x86_mpx_setup);
-
 #ifdef CONFIG_X86_64
 static int __init x86_nopcid_setup(char *s)
 {
@@ -307,8 +291,6 @@ static inline void squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
 static __init int setup_disable_smep(char *arg)
 {
 	setup_clear_cpu_cap(X86_FEATURE_SMEP);
-	/* Check for things that depend on SMEP being enabled: */
-	check_mpx_erratum(&boot_cpu_data);
 	return 1;
 }
 __setup("nosmep", setup_disable_smep);
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 11d5c5950e2d..ea5899f79f36 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -32,41 +32,6 @@
 #endif
 
 /*
- * Just in case our CPU detection goes bad, or you have a weird system,
- * allow a way to override the automatic disabling of MPX.
- */
-static int forcempx;
-
-static int __init forcempx_setup(char *__unused)
-{
-	forcempx = 1;
-
-	return 1;
-}
-__setup("intel-skd-046-workaround=disable", forcempx_setup);
-
-void check_mpx_erratum(struct cpuinfo_x86 *c)
-{
-	if (forcempx)
-		return;
-	/*
-	 * Turn off the MPX feature on CPUs where SMEP is not
-	 * available or disabled.
-	 *
-	 * Works around Intel Erratum SKD046: "Branch Instructions
-	 * May Initialize MPX Bound Registers Incorrectly".
-	 *
-	 * This might falsely disable MPX on systems without
-	 * SMEP, like Atom processors without SMEP.  But there
-	 * is no such hardware known at the moment.
-	 */
-	if (cpu_has(c, X86_FEATURE_MPX) && !cpu_has(c, X86_FEATURE_SMEP)) {
-		setup_clear_cpu_cap(X86_FEATURE_MPX);
-		pr_warn("x86/mpx: Disabling MPX since SMEP not present\n");
-	}
-}
-
-/*
  * Processors which have self-snooping capability can handle conflicting
  * memory type across CPUs by snooping its own cache. However, there exists
  * CPU models in which having conflicting memory types still leads to
@@ -330,7 +295,6 @@ static void early_init_intel(struct cpuinfo_x86 *c)
 			c->x86_coreid_bits = get_count_order((ebx >> 16) & 0xff);
 	}
 
-	check_mpx_erratum(c);
 	check_memory_type_self_snoop_errata(c);
 
 	/*
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 77ea96b794bd..6cf206806be0 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -947,8 +947,6 @@ void __init setup_arch(char **cmdline_p)
 	init_mm.end_data = (unsigned long) _edata;
 	init_mm.brk = _brk_end;
 
-	mpx_mm_init(&init_mm);
-
 	code_resource.start = __pa_symbol(_text);
 	code_resource.end = __pa_symbol(_etext)-1;
 	data_resource.start = __pa_symbol(_etext);
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index f7476ce23b6e..ca3c11a17b5a 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -22,7 +22,6 @@
 #include <asm/elf.h>
 #include <asm/ia32.h>
 #include <asm/syscalls.h>
-#include <asm/mpx.h>
 
 /*
  * Align a virtual address to avoid aliasing in the I$ on AMD F15h.
@@ -137,10 +136,6 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	struct vm_unmapped_area_info info;
 	unsigned long begin, end;
 
-	addr = mpx_unmapped_area_check(addr, len, flags);
-	if (IS_ERR_VALUE(addr))
-		return addr;
-
 	if (flags & MAP_FIXED)
 		return addr;
 
@@ -180,10 +175,6 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	unsigned long addr = addr0;
 	struct vm_unmapped_area_info info;
 
-	addr = mpx_unmapped_area_check(addr, len, flags);
-	if (IS_ERR_VALUE(addr))
-		return addr;
-
 	/* requested length too big for entire address space */
 	if (len > TASK_SIZE)
 		return -ENOMEM;
diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c
index fab095362c50..5bfd5aef5378 100644
--- a/arch/x86/mm/hugetlbpage.c
+++ b/arch/x86/mm/hugetlbpage.c
@@ -19,7 +19,6 @@
 #include <asm/tlbflush.h>
 #include <asm/pgalloc.h>
 #include <asm/elf.h>
-#include <asm/mpx.h>
 
 #if 0	/* This is just for testing */
 struct page *
@@ -151,10 +150,6 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 	if (len & ~huge_page_mask(h))
 		return -EINVAL;
 
-	addr = mpx_unmapped_area_check(addr, len, flags);
-	if (IS_ERR_VALUE(addr))
-		return addr;
-
 	if (len > TASK_SIZE)
 		return -ENOMEM;
 
diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c
index aae9a933dfd4..cb91eccc4960 100644
--- a/arch/x86/mm/mmap.c
+++ b/arch/x86/mm/mmap.c
@@ -163,8 +163,6 @@ unsigned long get_mmap_base(int is_legacy)
 
 const char *arch_vma_name(struct vm_area_struct *vma)
 {
-	if (vma->vm_flags & VM_MPX)
-		return "[mpx]";
 	return NULL;
 }
 
diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c
deleted file mode 100644
index 895fb7a9294d..000000000000
--- a/arch/x86/mm/mpx.c
+++ /dev/null
@@ -1,938 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * mpx.c - Memory Protection eXtensions
- *
- * Copyright (c) 2014, Intel Corporation.
- * Qiaowei Ren <qiaowei.ren@intel.com>
- * Dave Hansen <dave.hansen@intel.com>
- */
-#include <linux/kernel.h>
-#include <linux/slab.h>
-#include <linux/mm_types.h>
-#include <linux/mman.h>
-#include <linux/syscalls.h>
-#include <linux/sched/sysctl.h>
-
-#include <asm/insn.h>
-#include <asm/insn-eval.h>
-#include <asm/mmu_context.h>
-#include <asm/mpx.h>
-#include <asm/processor.h>
-#include <asm/fpu/internal.h>
-
-#define CREATE_TRACE_POINTS
-#include <asm/trace/mpx.h>
-
-static inline unsigned long mpx_bd_size_bytes(struct mm_struct *mm)
-{
-	if (is_64bit_mm(mm))
-		return MPX_BD_SIZE_BYTES_64;
-	else
-		return MPX_BD_SIZE_BYTES_32;
-}
-
-static inline unsigned long mpx_bt_size_bytes(struct mm_struct *mm)
-{
-	if (is_64bit_mm(mm))
-		return MPX_BT_SIZE_BYTES_64;
-	else
-		return MPX_BT_SIZE_BYTES_32;
-}
-
-/*
- * This is really a simplified "vm_mmap". it only handles MPX
- * bounds tables (the bounds directory is user-allocated).
- */
-static unsigned long mpx_mmap(unsigned long len)
-{
-	struct mm_struct *mm = current->mm;
-	unsigned long addr, populate;
-
-	/* Only bounds table can be allocated here */
-	if (len != mpx_bt_size_bytes(mm))
-		return -EINVAL;
-
-	down_write(&mm->mmap_sem);
-	addr = do_mmap(NULL, 0, len, PROT_READ | PROT_WRITE,
-		       MAP_ANONYMOUS | MAP_PRIVATE, VM_MPX, 0, &populate, NULL);
-	up_write(&mm->mmap_sem);
-	if (populate)
-		mm_populate(addr, populate);
-
-	return addr;
-}
-
-static int mpx_insn_decode(struct insn *insn,
-			   struct pt_regs *regs)
-{
-	unsigned char buf[MAX_INSN_SIZE];
-	int x86_64 = !test_thread_flag(TIF_IA32);
-	int not_copied;
-	int nr_copied;
-
-	not_copied = copy_from_user(buf, (void __user *)regs->ip, sizeof(buf));
-	nr_copied = sizeof(buf) - not_copied;
-	/*
-	 * The decoder _should_ fail nicely if we pass it a short buffer.
-	 * But, let's not depend on that implementation detail.  If we
-	 * did not get anything, just error out now.
-	 */
-	if (!nr_copied)
-		return -EFAULT;
-	insn_init(insn, buf, nr_copied, x86_64);
-	insn_get_length(insn);
-	/*
-	 * copy_from_user() tries to get as many bytes as we could see in
-	 * the largest possible instruction.  If the instruction we are
-	 * after is shorter than that _and_ we attempt to copy from
-	 * something unreadable, we might get a short read.  This is OK
-	 * as long as the read did not stop in the middle of the
-	 * instruction.  Check to see if we got a partial instruction.
-	 */
-	if (nr_copied < insn->length)
-		return -EFAULT;
-
-	insn_get_opcode(insn);
-	/*
-	 * We only _really_ need to decode bndcl/bndcn/bndcu
-	 * Error out on anything else.
-	 */
-	if (insn->opcode.bytes[0] != 0x0f)
-		goto bad_opcode;
-	if ((insn->opcode.bytes[1] != 0x1a) &&
-	    (insn->opcode.bytes[1] != 0x1b))
-		goto bad_opcode;
-
-	return 0;
-bad_opcode:
-	return -EINVAL;
-}
-
-/*
- * If a bounds overflow occurs then a #BR is generated. This
- * function decodes MPX instructions to get violation address
- * and set this address into extended struct siginfo.
- *
- * Note that this is not a super precise way of doing this.
- * Userspace could have, by the time we get here, written
- * anything it wants in to the instructions.  We can not
- * trust anything about it.  They might not be valid
- * instructions or might encode invalid registers, etc...
- */
-int mpx_fault_info(struct mpx_fault_info *info, struct pt_regs *regs)
-{
-	const struct mpx_bndreg_state *bndregs;
-	const struct mpx_bndreg *bndreg;
-	struct insn insn;
-	uint8_t bndregno;
-	int err;
-
-	err = mpx_insn_decode(&insn, regs);
-	if (err)
-		goto err_out;
-
-	/*
-	 * We know at this point that we are only dealing with
-	 * MPX instructions.
-	 */
-	insn_get_modrm(&insn);
-	bndregno = X86_MODRM_REG(insn.modrm.value);
-	if (bndregno > 3) {
-		err = -EINVAL;
-		goto err_out;
-	}
-	/* get bndregs field from current task's xsave area */
-	bndregs = get_xsave_field_ptr(XFEATURE_BNDREGS);
-	if (!bndregs) {
-		err = -EINVAL;
-		goto err_out;
-	}
-	/* now go select the individual register in the set of 4 */
-	bndreg = &bndregs->bndreg[bndregno];
-
-	/*
-	 * The registers are always 64-bit, but the upper 32
-	 * bits are ignored in 32-bit mode.  Also, note that the
-	 * upper bounds are architecturally represented in 1's
-	 * complement form.
-	 *
-	 * The 'unsigned long' cast is because the compiler
-	 * complains when casting from integers to different-size
-	 * pointers.
-	 */
-	info->lower = (void __user *)(unsigned long)bndreg->lower_bound;
-	info->upper = (void __user *)(unsigned long)~bndreg->upper_bound;
-	info->addr  = insn_get_addr_ref(&insn, regs);
-
-	/*
-	 * We were not able to extract an address from the instruction,
-	 * probably because there was something invalid in it.
-	 */
-	if (info->addr == (void __user *)-1) {
-		err = -EINVAL;
-		goto err_out;
-	}
-	trace_mpx_bounds_register_exception(info->addr, bndreg);
-	return 0;
-err_out:
-	/* info might be NULL, but kfree() handles that */
-	return err;
-}
-
-static __user void *mpx_get_bounds_dir(void)
-{
-	const struct mpx_bndcsr *bndcsr;
-
-	if (!cpu_feature_enabled(X86_FEATURE_MPX))
-		return MPX_INVALID_BOUNDS_DIR;
-
-	/*
-	 * The bounds directory pointer is stored in a register
-	 * only accessible if we first do an xsave.
-	 */
-	bndcsr = get_xsave_field_ptr(XFEATURE_BNDCSR);
-	if (!bndcsr)
-		return MPX_INVALID_BOUNDS_DIR;
-
-	/*
-	 * Make sure the register looks valid by checking the
-	 * enable bit.
-	 */
-	if (!(bndcsr->bndcfgu & MPX_BNDCFG_ENABLE_FLAG))
-		return MPX_INVALID_BOUNDS_DIR;
-
-	/*
-	 * Lastly, mask off the low bits used for configuration
-	 * flags, and return the address of the bounds table.
-	 */
-	return (void __user *)(unsigned long)
-		(bndcsr->bndcfgu & MPX_BNDCFG_ADDR_MASK);
-}
-
-int mpx_enable_management(void)
-{
-	void __user *bd_base = MPX_INVALID_BOUNDS_DIR;
-	struct mm_struct *mm = current->mm;
-	int ret = 0;
-
-	/*
-	 * 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.
-	 *
-	 * The copy_xregs_to_kernel() beneath get_xsave_field_ptr() is
-	 * expected to be relatively expensive. Storing the bounds
-	 * directory here means that we do not have to do xsave in the
-	 * unmap path; we can just use mm->context.bd_addr instead.
-	 */
-	bd_base = mpx_get_bounds_dir();
-	down_write(&mm->mmap_sem);
-
-	/* MPX doesn't support addresses above 47 bits yet. */
-	if (find_vma(mm, DEFAULT_MAP_WINDOW)) {
-		pr_warn_once("%s (%d): MPX cannot handle addresses "
-				"above 47-bits. Disabling.",
-				current->comm, current->pid);
-		ret = -ENXIO;
-		goto out;
-	}
-	mm->context.bd_addr = bd_base;
-	if (mm->context.bd_addr == MPX_INVALID_BOUNDS_DIR)
-		ret = -ENXIO;
-out:
-	up_write(&mm->mmap_sem);
-	return ret;
-}
-
-int mpx_disable_management(void)
-{
-	struct mm_struct *mm = current->mm;
-
-	if (!cpu_feature_enabled(X86_FEATURE_MPX))
-		return -ENXIO;
-
-	down_write(&mm->mmap_sem);
-	mm->context.bd_addr = MPX_INVALID_BOUNDS_DIR;
-	up_write(&mm->mmap_sem);
-	return 0;
-}
-
-static int mpx_cmpxchg_bd_entry(struct mm_struct *mm,
-		unsigned long *curval,
-		unsigned long __user *addr,
-		unsigned long old_val, unsigned long new_val)
-{
-	int ret;
-	/*
-	 * user_atomic_cmpxchg_inatomic() actually uses sizeof()
-	 * the pointer that we pass to it to figure out how much
-	 * data to cmpxchg.  We have to be careful here not to
-	 * pass a pointer to a 64-bit data type when we only want
-	 * a 32-bit copy.
-	 */
-	if (is_64bit_mm(mm)) {
-		ret = user_atomic_cmpxchg_inatomic(curval,
-				addr, old_val, new_val);
-	} else {
-		u32 uninitialized_var(curval_32);
-		u32 old_val_32 = old_val;
-		u32 new_val_32 = new_val;
-		u32 __user *addr_32 = (u32 __user *)addr;
-
-		ret = user_atomic_cmpxchg_inatomic(&curval_32,
-				addr_32, old_val_32, new_val_32);
-		*curval = curval_32;
-	}
-	return ret;
-}
-
-/*
- * With 32-bit mode, a bounds directory is 4MB, and the size of each
- * bounds table is 16KB. With 64-bit mode, a bounds directory is 2GB,
- * and the size of each bounds table is 4MB.
- */
-static int allocate_bt(struct mm_struct *mm, long __user *bd_entry)
-{
-	unsigned long expected_old_val = 0;
-	unsigned long actual_old_val = 0;
-	unsigned long bt_addr;
-	unsigned long bd_new_entry;
-	int ret = 0;
-
-	/*
-	 * Carve the virtual space out of userspace for the new
-	 * bounds table:
-	 */
-	bt_addr = mpx_mmap(mpx_bt_size_bytes(mm));
-	if (IS_ERR((void *)bt_addr))
-		return PTR_ERR((void *)bt_addr);
-	/*
-	 * Set the valid flag (kinda like _PAGE_PRESENT in a pte)
-	 */
-	bd_new_entry = bt_addr | MPX_BD_ENTRY_VALID_FLAG;
-
-	/*
-	 * Go poke the address of the new bounds table in to the
-	 * bounds directory entry out in userspace memory.  Note:
-	 * we may race with another CPU instantiating the same table.
-	 * In that case the cmpxchg will see an unexpected
-	 * 'actual_old_val'.
-	 *
-	 * This can fault, but that's OK because we do not hold
-	 * mmap_sem at this point, unlike some of the other part
-	 * of the MPX code that have to pagefault_disable().
-	 */
-	ret = mpx_cmpxchg_bd_entry(mm, &actual_old_val,	bd_entry,
-				   expected_old_val, bd_new_entry);
-	if (ret)
-		goto out_unmap;
-
-	/*
-	 * The user_atomic_cmpxchg_inatomic() will only return nonzero
-	 * for faults, *not* if the cmpxchg itself fails.  Now we must
-	 * verify that the cmpxchg itself completed successfully.
-	 */
-	/*
-	 * We expected an empty 'expected_old_val', but instead found
-	 * an apparently valid entry.  Assume we raced with another
-	 * thread to instantiate this table and desclare succecss.
-	 */
-	if (actual_old_val & MPX_BD_ENTRY_VALID_FLAG) {
-		ret = 0;
-		goto out_unmap;
-	}
-	/*
-	 * We found a non-empty bd_entry but it did not have the
-	 * VALID_FLAG set.  Return an error which will result in
-	 * a SEGV since this probably means that somebody scribbled
-	 * some invalid data in to a bounds table.
-	 */
-	if (expected_old_val != actual_old_val) {
-		ret = -EINVAL;
-		goto out_unmap;
-	}
-	trace_mpx_new_bounds_table(bt_addr);
-	return 0;
-out_unmap:
-	vm_munmap(bt_addr, mpx_bt_size_bytes(mm));
-	return ret;
-}
-
-/*
- * When a BNDSTX instruction attempts to save bounds to a bounds
- * table, it will first attempt to look up the table in the
- * first-level bounds directory.  If it does not find a table in
- * the directory, a #BR is generated and we get here in order to
- * allocate a new table.
- *
- * With 32-bit mode, the size of BD is 4MB, and the size of each
- * bound table is 16KB. With 64-bit mode, the size of BD is 2GB,
- * and the size of each bound table is 4MB.
- */
-static int do_mpx_bt_fault(void)
-{
-	unsigned long bd_entry, bd_base;
-	const struct mpx_bndcsr *bndcsr;
-	struct mm_struct *mm = current->mm;
-
-	bndcsr = get_xsave_field_ptr(XFEATURE_BNDCSR);
-	if (!bndcsr)
-		return -EINVAL;
-	/*
-	 * Mask off the preserve and enable bits
-	 */
-	bd_base = bndcsr->bndcfgu & MPX_BNDCFG_ADDR_MASK;
-	/*
-	 * The hardware provides the address of the missing or invalid
-	 * entry via BNDSTATUS, so we don't have to go look it up.
-	 */
-	bd_entry = bndcsr->bndstatus & MPX_BNDSTA_ADDR_MASK;
-	/*
-	 * Make sure the directory entry is within where we think
-	 * the directory is.
-	 */
-	if ((bd_entry < bd_base) ||
-	    (bd_entry >= bd_base + mpx_bd_size_bytes(mm)))
-		return -EINVAL;
-
-	return allocate_bt(mm, (long __user *)bd_entry);
-}
-
-int mpx_handle_bd_fault(void)
-{
-	/*
-	 * Userspace never asked us to manage the bounds tables,
-	 * so refuse to help.
-	 */
-	if (