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authorLinus Torvalds <torvalds@linux-foundation.org>2018-02-08 10:44:25 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-08 10:44:25 -0800
commitc0136321924dd338bb8fc5661c4b0e27441a8d04 (patch)
tree099cc60dfe6793309b21474a00e4d10087a7cae8 /arch/arm64/include
parent846ade7dd2e630a309a8c57302046e8c4037b8df (diff)
parent3a0a397ff5ff8b56ca9f7908b75dee6bf0b5fabb (diff)
downloadlinux-c0136321924dd338bb8fc5661c4b0e27441a8d04.tar.gz
Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull more arm64 updates from Catalin Marinas:
 "As I mentioned in the last pull request, there's a second batch of
  security updates for arm64 with mitigations for Spectre/v1 and an
  improved one for Spectre/v2 (via a newly defined firmware interface
  API).

  Spectre v1 mitigation:

   - back-end version of array_index_mask_nospec()

   - masking of the syscall number to restrict speculation through the
     syscall table

   - masking of __user pointers prior to deference in uaccess routines

  Spectre v2 mitigation update:

   - using the new firmware SMC calling convention specification update

   - removing the current PSCI GET_VERSION firmware call mitigation as
     vendors are deploying new SMCCC-capable firmware

   - additional branch predictor hardening for synchronous exceptions
     and interrupts while in user mode

  Meltdown v3 mitigation update:

    - Cavium Thunder X is unaffected but a hardware erratum gets in the
      way. The kernel now starts with the page tables mapped as global
      and switches to non-global if kpti needs to be enabled.

  Other:

   - Theoretical trylock bug fixed"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (38 commits)
  arm64: Kill PSCI_GET_VERSION as a variant-2 workaround
  arm64: Add ARM_SMCCC_ARCH_WORKAROUND_1 BP hardening support
  arm/arm64: smccc: Implement SMCCC v1.1 inline primitive
  arm/arm64: smccc: Make function identifiers an unsigned quantity
  firmware/psci: Expose SMCCC version through psci_ops
  firmware/psci: Expose PSCI conduit
  arm64: KVM: Add SMCCC_ARCH_WORKAROUND_1 fast handling
  arm64: KVM: Report SMCCC_ARCH_WORKAROUND_1 BP hardening support
  arm/arm64: KVM: Turn kvm_psci_version into a static inline
  arm/arm64: KVM: Advertise SMCCC v1.1
  arm/arm64: KVM: Implement PSCI 1.0 support
  arm/arm64: KVM: Add smccc accessors to PSCI code
  arm/arm64: KVM: Add PSCI_VERSION helper
  arm/arm64: KVM: Consolidate the PSCI include files
  arm64: KVM: Increment PC after handling an SMC trap
  arm: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls
  arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls
  arm64: entry: Apply BP hardening for suspicious interrupts from EL0
  arm64: entry: Apply BP hardening for high-priority synchronous exceptions
  arm64: futex: Mask __user pointers prior to dereference
  ...
Diffstat (limited to 'arch/arm64/include')
-rw-r--r--arch/arm64/include/asm/assembler.h43
-rw-r--r--arch/arm64/include/asm/barrier.h22
-rw-r--r--arch/arm64/include/asm/futex.h9
-rw-r--r--arch/arm64/include/asm/kernel-pgtable.h12
-rw-r--r--arch/arm64/include/asm/kvm_host.h6
-rw-r--r--arch/arm64/include/asm/kvm_psci.h27
-rw-r--r--arch/arm64/include/asm/pgtable-prot.h30
-rw-r--r--arch/arm64/include/asm/processor.h3
-rw-r--r--arch/arm64/include/asm/spinlock.h4
-rw-r--r--arch/arm64/include/asm/uaccess.h155
10 files changed, 204 insertions, 107 deletions
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 3873dd7b5a32..1241fb211293 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -116,6 +116,24 @@
 	.endm
 
 /*
+ * Value prediction barrier
+ */
+	.macro	csdb
+	hint	#20
+	.endm
+
+/*
+ * Sanitise a 64-bit bounded index wrt speculation, returning zero if out
+ * of bounds.
+ */
+	.macro	mask_nospec64, idx, limit, tmp
+	sub	\tmp, \idx, \limit
+	bic	\tmp, \tmp, \idx
+	and	\idx, \idx, \tmp, asr #63
+	csdb
+	.endm
+
+/*
  * NOP sequence
  */
 	.macro	nops, num
@@ -514,7 +532,7 @@ alternative_endif
  * 	phys:	physical address, preserved
  * 	ttbr:	returns the TTBR value
  */
-	.macro	phys_to_ttbr, phys, ttbr
+	.macro	phys_to_ttbr, ttbr, phys
 #ifdef CONFIG_ARM64_PA_BITS_52
 	orr	\ttbr, \phys, \phys, lsr #46
 	and	\ttbr, \ttbr, #TTBR_BADDR_MASK_52
@@ -523,6 +541,29 @@ alternative_endif
 #endif
 	.endm
 
+	.macro	phys_to_pte, pte, phys
+#ifdef CONFIG_ARM64_PA_BITS_52
+	/*
+	 * We assume \phys is 64K aligned and this is guaranteed by only
+	 * supporting this configuration with 64K pages.
+	 */
+	orr	\pte, \phys, \phys, lsr #36
+	and	\pte, \pte, #PTE_ADDR_MASK
+#else
+	mov	\pte, \phys
+#endif
+	.endm
+
+	.macro	pte_to_phys, phys, pte
+#ifdef CONFIG_ARM64_PA_BITS_52
+	ubfiz	\phys, \pte, #(48 - 16 - 12), #16
+	bfxil	\phys, \pte, #16, #32
+	lsl	\phys, \phys, #16
+#else
+	and	\phys, \pte, #PTE_ADDR_MASK
+#endif
+	.endm
+
 /**
  * Errata workaround prior to disable MMU. Insert an ISB immediately prior
  * to executing the MSR that will change SCTLR_ELn[M] from a value of 1 to 0.
diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h
index 77651c49ef44..f11518af96a9 100644
--- a/arch/arm64/include/asm/barrier.h
+++ b/arch/arm64/include/asm/barrier.h
@@ -32,6 +32,7 @@
 #define dsb(opt)	asm volatile("dsb " #opt : : : "memory")
 
 #define psb_csync()	asm volatile("hint #17" : : : "memory")
+#define csdb()		asm volatile("hint #20" : : : "memory")
 
 #define mb()		dsb(sy)
 #define rmb()		dsb(ld)
@@ -40,6 +41,27 @@
 #define dma_rmb()	dmb(oshld)
 #define dma_wmb()	dmb(oshst)
 
+/*
+ * Generate a mask for array_index__nospec() that is ~0UL when 0 <= idx < sz
+ * and 0 otherwise.
+ */
+#define array_index_mask_nospec array_index_mask_nospec
+static inline unsigned long array_index_mask_nospec(unsigned long idx,
+						    unsigned long sz)
+{
+	unsigned long mask;
+
+	asm volatile(
+	"	cmp	%1, %2\n"
+	"	sbc	%0, xzr, xzr\n"
+	: "=r" (mask)
+	: "r" (idx), "Ir" (sz)
+	: "cc");
+
+	csdb();
+	return mask;
+}
+
 #define __smp_mb()	dmb(ish)
 #define __smp_rmb()	dmb(ishld)
 #define __smp_wmb()	dmb(ishst)
diff --git a/arch/arm64/include/asm/futex.h b/arch/arm64/include/asm/futex.h
index 5bb2fd4674e7..07fe2479d310 100644
--- a/arch/arm64/include/asm/futex.h
+++ b/arch/arm64/include/asm/futex.h
@@ -48,9 +48,10 @@ do {									\
 } while (0)
 
 static inline int
-arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
+arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *_uaddr)
 {
 	int oldval = 0, ret, tmp;
+	u32 __user *uaddr = __uaccess_mask_ptr(_uaddr);
 
 	pagefault_disable();
 
@@ -88,15 +89,17 @@ arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
 }
 
 static inline int
-futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
+futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *_uaddr,
 			      u32 oldval, u32 newval)
 {
 	int ret = 0;
 	u32 val, tmp;
+	u32 __user *uaddr;
 
-	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
+	if (!access_ok(VERIFY_WRITE, _uaddr, sizeof(u32)))
 		return -EFAULT;
 
+	uaddr = __uaccess_mask_ptr(_uaddr);
 	uaccess_enable();
 	asm volatile("// futex_atomic_cmpxchg_inatomic\n"
 "	prfm	pstl1strm, %2\n"
diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h
index 82386e860dd2..a780f6714b44 100644
--- a/arch/arm64/include/asm/kernel-pgtable.h
+++ b/arch/arm64/include/asm/kernel-pgtable.h
@@ -123,16 +123,8 @@
 /*
  * Initial memory map attributes.
  */
-#define _SWAPPER_PTE_FLAGS	(PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
-#define _SWAPPER_PMD_FLAGS	(PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
-
-#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
-#define SWAPPER_PTE_FLAGS	(_SWAPPER_PTE_FLAGS | PTE_NG)
-#define SWAPPER_PMD_FLAGS	(_SWAPPER_PMD_FLAGS | PMD_SECT_NG)
-#else
-#define SWAPPER_PTE_FLAGS	_SWAPPER_PTE_FLAGS
-#define SWAPPER_PMD_FLAGS	_SWAPPER_PMD_FLAGS
-#endif
+#define SWAPPER_PTE_FLAGS	(PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
+#define SWAPPER_PMD_FLAGS	(PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
 
 #if ARM64_SWAPPER_USES_SECTION_MAPS
 #define SWAPPER_MM_MMUFLAGS	(PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 4485ae8e98de..a73f63aca68e 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -415,4 +415,10 @@ static inline void kvm_arm_vhe_guest_exit(void)
 {
 	local_daif_restore(DAIF_PROCCTX_NOIRQ);
 }
+
+static inline bool kvm_arm_harden_branch_predictor(void)
+{
+	return cpus_have_const_cap(ARM64_HARDEN_BRANCH_PREDICTOR);
+}
+
 #endif /* __ARM64_KVM_HOST_H__ */
diff --git a/arch/arm64/include/asm/kvm_psci.h b/arch/arm64/include/asm/kvm_psci.h
deleted file mode 100644
index bc39e557c56c..000000000000
--- a/arch/arm64/include/asm/kvm_psci.h
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
- * Copyright (C) 2012,2013 - ARM Ltd
- * Author: Marc Zyngier <marc.zyngier@arm.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifndef __ARM64_KVM_PSCI_H__
-#define __ARM64_KVM_PSCI_H__
-
-#define KVM_ARM_PSCI_0_1	1
-#define KVM_ARM_PSCI_0_2	2
-
-int kvm_psci_version(struct kvm_vcpu *vcpu);
-int kvm_psci_call(struct kvm_vcpu *vcpu);
-
-#endif /* __ARM64_KVM_PSCI_H__ */
diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
index 22a926825e3f..2db84df5eb42 100644
--- a/arch/arm64/include/asm/pgtable-prot.h
+++ b/arch/arm64/include/asm/pgtable-prot.h
@@ -37,13 +37,11 @@
 #define _PROT_DEFAULT		(PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
 #define _PROT_SECT_DEFAULT	(PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
 
-#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
-#define PROT_DEFAULT		(_PROT_DEFAULT | PTE_NG)
-#define PROT_SECT_DEFAULT	(_PROT_SECT_DEFAULT | PMD_SECT_NG)
-#else
-#define PROT_DEFAULT		_PROT_DEFAULT
-#define PROT_SECT_DEFAULT	_PROT_SECT_DEFAULT
-#endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */
+#define PTE_MAYBE_NG		(arm64_kernel_unmapped_at_el0() ? PTE_NG : 0)
+#define PMD_MAYBE_NG		(arm64_kernel_unmapped_at_el0() ? PMD_SECT_NG : 0)
+
+#define PROT_DEFAULT		(_PROT_DEFAULT | PTE_MAYBE_NG)
+#define PROT_SECT_DEFAULT	(_PROT_SECT_DEFAULT | PMD_MAYBE_NG)
 
 #define PROT_DEVICE_nGnRnE	(PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_DIRTY | PTE_WRITE | PTE_ATTRINDX(MT_DEVICE_nGnRnE))
 #define PROT_DEVICE_nGnRE	(PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_DIRTY | PTE_WRITE | PTE_ATTRINDX(MT_DEVICE_nGnRE))
@@ -55,22 +53,22 @@
 #define PROT_SECT_NORMAL	(PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
 #define PROT_SECT_NORMAL_EXEC	(PROT_SECT_DEFAULT | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
 
-#define _PAGE_DEFAULT		(PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL))
-#define _HYP_PAGE_DEFAULT	(_PAGE_DEFAULT & ~PTE_NG)
+#define _PAGE_DEFAULT		(_PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL))
+#define _HYP_PAGE_DEFAULT	_PAGE_DEFAULT
 
-#define PAGE_KERNEL		__pgprot(_PAGE_DEFAULT | PTE_PXN | PTE_UXN | PTE_DIRTY | PTE_WRITE)
-#define PAGE_KERNEL_RO		__pgprot(_PAGE_DEFAULT | PTE_PXN | PTE_UXN | PTE_DIRTY | PTE_RDONLY)
-#define PAGE_KERNEL_ROX		__pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_RDONLY)
-#define PAGE_KERNEL_EXEC	__pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_WRITE)
-#define PAGE_KERNEL_EXEC_CONT	__pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_WRITE | PTE_CONT)
+#define PAGE_KERNEL		__pgprot(PROT_NORMAL)
+#define PAGE_KERNEL_RO		__pgprot((PROT_NORMAL & ~PTE_WRITE) | PTE_RDONLY)
+#define PAGE_KERNEL_ROX		__pgprot((PROT_NORMAL & ~(PTE_WRITE | PTE_PXN)) | PTE_RDONLY)
+#define PAGE_KERNEL_EXEC	__pgprot(PROT_NORMAL & ~PTE_PXN)
+#define PAGE_KERNEL_EXEC_CONT	__pgprot((PROT_NORMAL & ~PTE_PXN) | PTE_CONT)
 
 #define PAGE_HYP		__pgprot(_HYP_PAGE_DEFAULT | PTE_HYP | PTE_HYP_XN)
 #define PAGE_HYP_EXEC		__pgprot(_HYP_PAGE_DEFAULT | PTE_HYP | PTE_RDONLY)
 #define PAGE_HYP_RO		__pgprot(_HYP_PAGE_DEFAULT | PTE_HYP | PTE_RDONLY | PTE_HYP_XN)
 #define PAGE_HYP_DEVICE		__pgprot(PROT_DEVICE_nGnRE | PTE_HYP)
 
-#define PAGE_S2			__pgprot(PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_NORMAL) | PTE_S2_RDONLY)
-#define PAGE_S2_DEVICE		__pgprot(PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_DEVICE_nGnRE) | PTE_S2_RDONLY | PTE_UXN)
+#define PAGE_S2			__pgprot(_PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_NORMAL) | PTE_S2_RDONLY)
+#define PAGE_S2_DEVICE		__pgprot(_PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_DEVICE_nGnRE) | PTE_S2_RDONLY | PTE_UXN)
 
 #define PAGE_NONE		__pgprot(((_PAGE_DEFAULT) & ~PTE_VALID) | PTE_PROT_NONE | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN)
 #define PAGE_SHARED		__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE)
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index 6db43ebd648d..fce604e3e599 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -21,6 +21,9 @@
 
 #define TASK_SIZE_64		(UL(1) << VA_BITS)
 
+#define KERNEL_DS	UL(-1)
+#define USER_DS		(TASK_SIZE_64 - 1)
+
 #ifndef __ASSEMBLY__
 
 /*
diff --git a/arch/arm64/include/asm/spinlock.h b/arch/arm64/include/asm/spinlock.h
index fdb827c7832f..ebdae15d665d 100644
--- a/arch/arm64/include/asm/spinlock.h
+++ b/arch/arm64/include/asm/spinlock.h
@@ -87,8 +87,8 @@ static inline int arch_spin_trylock(arch_spinlock_t *lock)
 	"	cbnz	%w1, 1f\n"
 	"	add	%w1, %w0, %3\n"
 	"	casa	%w0, %w1, %2\n"
-	"	and	%w1, %w1, #0xffff\n"
-	"	eor	%w1, %w1, %w0, lsr #16\n"
+	"	sub	%w1, %w1, %3\n"
+	"	eor	%w1, %w1, %w0\n"
 	"1:")
 	: "=&r" (lockval), "=&r" (tmp), "+Q" (*lock)
 	: "I" (1 << TICKET_SHIFT)
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index 59fda5292936..543e11f0f657 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -35,16 +35,20 @@
 #include <asm/compiler.h>
 #include <asm/extable.h>
 
-#define KERNEL_DS	(-1UL)
 #define get_ds()	(KERNEL_DS)
-
-#define USER_DS		TASK_SIZE_64
 #define get_fs()	(current_thread_info()->addr_limit)
 
 static inline void set_fs(mm_segment_t fs)
 {
 	current_thread_info()->addr_limit = fs;
 
+	/*
+	 * Prevent a mispredicted conditional call to set_fs from forwarding
+	 * the wrong address limit to access_ok under speculation.
+	 */
+	dsb(nsh);
+	isb();
+
 	/* On user-mode return, check fs is correct */
 	set_thread_flag(TIF_FSCHECK);
 
@@ -66,22 +70,32 @@ static inline void set_fs(mm_segment_t fs)
  * Returns 1 if the range is valid, 0 otherwise.
  *
  * This is equivalent to the following test:
- * (u65)addr + (u65)size <= current->addr_limit
- *
- * This needs 65-bit arithmetic.
+ * (u65)addr + (u65)size <= (u65)current->addr_limit + 1
  */
-#define __range_ok(addr, size)						\
-({									\
-	unsigned long __addr = (unsigned long)(addr);			\
-	unsigned long flag, roksum;					\
-	__chk_user_ptr(addr);						\
-	asm("adds %1, %1, %3; ccmp %1, %4, #2, cc; cset %0, ls"		\
-		: "=&r" (flag), "=&r" (roksum)				\
-		: "1" (__addr), "Ir" (size),				\
-		  "r" (current_thread_info()->addr_limit)		\
-		: "cc");						\
-	flag;								\
-})
+static inline unsigned long __range_ok(unsigned long addr, unsigned long size)
+{
+	unsigned long limit = current_thread_info()->addr_limit;
+
+	__chk_user_ptr(addr);
+	asm volatile(
+	// A + B <= C + 1 for all A,B,C, in four easy steps:
+	// 1: X = A + B; X' = X % 2^64
+	"	adds	%0, %0, %2\n"
+	// 2: Set C = 0 if X > 2^64, to guarantee X' > C in step 4
+	"	csel	%1, xzr, %1, hi\n"
+	// 3: Set X' = ~0 if X >= 2^64. For X == 2^64, this decrements X'
+	//    to compensate for the carry flag being set in step 4. For
+	//    X > 2^64, X' merely has to remain nonzero, which it does.
+	"	csinv	%0, %0, xzr, cc\n"
+	// 4: For X < 2^64, this gives us X' - C - 1 <= 0, where the -1
+	//    comes from the carry in being clear. Otherwise, we are
+	//    testing X' - C == 0, subject to the previous adjustments.
+	"	sbcs	xzr, %0, %1\n"
+	"	cset	%0, ls\n"
+	: "+r" (addr), "+r" (limit) : "Ir" (size) : "cc");
+
+	return addr;
+}
 
 /*
  * When dealing with data aborts, watchpoints, or instruction traps we may end
@@ -90,7 +104,7 @@ static inline void set_fs(mm_segment_t fs)
  */
 #define untagged_addr(addr)		sign_extend64(addr, 55)
 
-#define access_ok(type, addr, size)	__range_ok(addr, size)
+#define access_ok(type, addr, size)	__range_ok((unsigned long)(addr), size)
 #define user_addr_max			get_fs
 
 #define _ASM_EXTABLE(from, to)						\
@@ -221,6 +235,26 @@ static inline void uaccess_enable_not_uao(void)
 }
 
 /*
+ * Sanitise a uaccess pointer such that it becomes NULL if above the
+ * current addr_limit.
+ */
+#define uaccess_mask_ptr(ptr) (__typeof__(ptr))__uaccess_mask_ptr(ptr)
+static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
+{
+	void __user *safe_ptr;
+
+	asm volatile(
+	"	bics	xzr, %1, %2\n"
+	"	csel	%0, %1, xzr, eq\n"
+	: "=&r" (safe_ptr)
+	: "r" (ptr), "r" (current_thread_info()->addr_limit)
+	: "cc");
+
+	csdb();
+	return safe_ptr;
+}
+
+/*
  * The "__xxx" versions of the user access functions do not verify the address
  * space - it must have been done previously with a separate "access_ok()"
  * call.
@@ -272,28 +306,33 @@ do {									\
 	(x) = (__force __typeof__(*(ptr)))__gu_val;			\
 } while (0)
 
-#define __get_user(x, ptr)						\
+#define __get_user_check(x, ptr, err)					\
 ({									\
-	int __gu_err = 0;						\
-	__get_user_err((x), (ptr), __gu_err);				\
-	__gu_err;							\
+	__typeof__(*(ptr)) __user *__p = (ptr);				\
+	might_fault();							\
+	if (access_ok(VERIFY_READ, __p, sizeof(*__p))) {		\
+		__p = uaccess_mask_ptr(__p);				\
+		__get_user_err((x), __p, (err));			\
+	} else {							\
+		(x) = 0; (err) = -EFAULT;				\
+	}								\
 })
 
 #define __get_user_error(x, ptr, err)					\
 ({									\
-	__get_user_err((x), (ptr), (err));				\
+	__get_user_check((x), (ptr), (err));				\
 	(void)0;							\
 })
 
-#define get_user(x, ptr)						\
+#define __get_user(x, ptr)						\
 ({									\
-	__typeof__(*(ptr)) __user *__p = (ptr);				\
-	might_fault();							\
-	access_ok(VERIFY_READ, __p, sizeof(*__p)) ?			\
-		__get_user((x), __p) :					\
-		((x) = 0, -EFAULT);					\
+	int __gu_err = 0;						\
+	__get_user_check((x), (ptr), __gu_err);				\
+	__gu_err;							\
 })
 
+#define get_user	__get_user
+
 #define __put_user_asm(instr, alt_instr, reg, x, addr, err, feature)	\
 	asm volatile(							\
 	"1:"ALTERNATIVE(instr "     " reg "1, [%2]\n",			\
@@ -336,43 +375,63 @@ do {									\
 	uaccess_disable_not_uao();					\
 } while (0)
 
-#define __put_user(x, ptr)						\
+#define __put_user_check(x, ptr, err)					\
 ({									\
-	int __pu_err = 0;						\
-	__put_user_err((x), (ptr), __pu_err);				\
-	__pu_err;							\
+	__typeof__(*(ptr)) __user *__p = (ptr);				\
+	might_fault();							\
+	if (access_ok(VERIFY_WRITE, __p, sizeof(*__p))) {		\
+		__p = uaccess_mask_ptr(__p);				\
+		__put_user_err((x), __p, (err));			\
+	} else	{							\
+		(err) = -EFAULT;					\
+	}								\
 })
 
 #define __put_user_error(x, ptr, err)					\
 ({									\
-	__put_user_err((x), (ptr), (err));				\
+	__put_user_check((x), (ptr), (err));				\
 	(void)0;							\
 })
 
-#define put_user(x, ptr)						\
+#define __put_user(x, ptr)						\
 ({									\
-	__typeof__(*(ptr)) __user *__p = (ptr);				\
-	might_fault();							\
-	access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ?			\
-		__put_user((x), __p) :					\
-		-EFAULT;						\
+	int __pu_err = 0;						\
+	__put_user_check((x), (ptr), __pu_err);				\
+	__pu_err;							\
 })
 
+#define put_user	__put_user
+
 extern unsigned long __must_check __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
-#define raw_copy_from_user __arch_copy_from_user
+#define raw_copy_from_user(to, from, n)					\
+({									\
+	__arch_copy_from_user((to), __uaccess_mask_ptr(from), (n));	\
+})
+
 extern unsigned long __must_check __arch_copy_to_user(void __user *to, const void *from, unsigned long n);
-#define raw_copy_to_user __arch_copy_to_user
-extern unsigned long __must_check raw_copy_in_user(void __user *to, const void __user *from, unsigned long n);
-extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
+#define raw_copy_to_user(to, from, n)					\
+({									\
+	__arch_copy_to_user(__uaccess_mask_ptr(to), (from), (n));	\
+})
+
+extern unsigned long __must_check __arch_copy_in_user(void __user *to, const void __user *from, unsigned long n);
+#define raw_copy_in_user(to, from, n)					\
+({									\
+	__arch_copy_in_user(__uaccess_mask_ptr(to),			\
+			    __uaccess_mask_ptr(from), (n));		\
+})
+
 #define INLINE_COPY_TO_USER
 #define INLINE_COPY_FROM_USER
 
-static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
+extern unsigned long __must_check __arch_clear_user(void __user *to, unsigned long n);
+static inline unsigned long __must_check __clear_user(void __user *to, unsigned long n)
 {
 	if (access_ok(VERIFY_WRITE, to, n))
-		n = __clear_user(to, n);
+		n = __arch_clear_user(__uaccess_mask_ptr(to), n);
 	return n;
 }
+#define clear_user	__clear_user
 
 extern long strncpy_from_user(char *dest, const char __user *src, long count);
 
@@ -386,7 +445,7 @@ extern unsigned long __must_check __copy_user_flushcache(void *to, const void __
 static inline int __copy_from_user_flushcache(void *dst, const void __user *src, unsigned size)
 {
 	kasan_check_write(dst, size);
-	return __copy_user_flushcache(dst, src, size);
+	return __copy_user_flushcache(dst, __uaccess_mask_ptr(src), size);
 }
 #endif