14 files changed, 643 insertions, 14 deletions

diff --git a/arch/sparc/kernel/Makefile b/arch/sparc/kernel/Makefile
index cc97545737f0..76cb57750dda 100644
--- a/arch/sparc/kernel/Makefile
+++ b/arch/sparc/kernel/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_SPARC64)   += visemul.o
 obj-$(CONFIG_SPARC64)   += hvapi.o
 obj-$(CONFIG_SPARC64)   += sstate.o
 obj-$(CONFIG_SPARC64)   += mdesc.o
+obj-$(CONFIG_SPARC64)   += adi_64.o
 obj-$(CONFIG_SPARC64)	+= pcr.o
 obj-$(CONFIG_SPARC64)	+= nmi.o
 obj-$(CONFIG_SPARC64_SMP) += cpumap.o
diff --git a/arch/sparc/kernel/adi_64.c b/arch/sparc/kernel/adi_64.c
new file mode 100644
index 000000000000..d0a2ac975b42
--- /dev/null
+++ b/arch/sparc/kernel/adi_64.c
@@ -0,0 +1,397 @@
+/* adi_64.c: support for ADI (Application Data Integrity) feature on
+ * sparc m7 and newer processors. This feature is also known as
+ * SSM (Silicon Secured Memory).
+ *
+ * Copyright (C) 2016 Oracle and/or its affiliates. All rights reserved.
+ * Author: Khalid Aziz (khalid.aziz@oracle.com)
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ */
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/mm_types.h>
+#include <asm/mdesc.h>
+#include <asm/adi_64.h>
+#include <asm/mmu_64.h>
+#include <asm/pgtable_64.h>
+
+/* Each page of storage for ADI tags can accommodate tags for 128
+ * pages. When ADI enabled pages are being swapped out, it would be
+ * prudent to allocate at least enough tag storage space to accommodate
+ * SWAPFILE_CLUSTER number of pages. Allocate enough tag storage to
+ * store tags for four SWAPFILE_CLUSTER pages to reduce need for
+ * further allocations for same vma.
+ */
+#define TAG_STORAGE_PAGES	8
+
+struct adi_config adi_state;
+EXPORT_SYMBOL(adi_state);
+
+/* mdesc_adi_init() : Parse machine description provided by the
+ *	hypervisor to detect ADI capabilities
+ *
+ * Hypervisor reports ADI capabilities of platform in "hwcap-list" property
+ * for "cpu" node. If the platform supports ADI, "hwcap-list" property
+ * contains the keyword "adp". If the platform supports ADI, "platform"
+ * node will contain "adp-blksz", "adp-nbits" and "ue-on-adp" properties
+ * to describe the ADI capabilities.
+ */
+void __init mdesc_adi_init(void)
+{
+	struct mdesc_handle *hp = mdesc_grab();
+	const char *prop;
+	u64 pn, *val;
+	int len;
+
+	if (!hp)
+		goto adi_not_found;
+
+	pn = mdesc_node_by_name(hp, MDESC_NODE_NULL, "cpu");
+	if (pn == MDESC_NODE_NULL)
+		goto adi_not_found;
+
+	prop = mdesc_get_property(hp, pn, "hwcap-list", &len);
+	if (!prop)
+		goto adi_not_found;
+
+	/*
+	 * Look for "adp" keyword in hwcap-list which would indicate
+	 * ADI support
+	 */
+	adi_state.enabled = false;
+	while (len) {
+		int plen;
+
+		if (!strcmp(prop, "adp")) {
+			adi_state.enabled = true;
+			break;
+		}
+
+		plen = strlen(prop) + 1;
+		prop += plen;
+		len -= plen;
+	}
+
+	if (!adi_state.enabled)
+		goto adi_not_found;
+
+	/* Find the ADI properties in "platform" node. If all ADI
+	 * properties are not found, ADI support is incomplete and
+	 * do not enable ADI in the kernel.
+	 */
+	pn = mdesc_node_by_name(hp, MDESC_NODE_NULL, "platform");
+	if (pn == MDESC_NODE_NULL)
+		goto adi_not_found;
+
+	val = (u64 *) mdesc_get_property(hp, pn, "adp-blksz", &len);
+	if (!val)
+		goto adi_not_found;
+	adi_state.caps.blksz = *val;
+
+	val = (u64 *) mdesc_get_property(hp, pn, "adp-nbits", &len);
+	if (!val)
+		goto adi_not_found;
+	adi_state.caps.nbits = *val;
+
+	val = (u64 *) mdesc_get_property(hp, pn, "ue-on-adp", &len);
+	if (!val)
+		goto adi_not_found;
+	adi_state.caps.ue_on_adi = *val;
+
+	/* Some of the code to support swapping ADI tags is written
+	 * assumption that two ADI tags can fit inside one byte. If
+	 * this assumption is broken by a future architecture change,
+	 * that code will have to be revisited. If that were to happen,
+	 * disable ADI support so we do not get unpredictable results
+	 * with programs trying to use ADI and their pages getting
+	 * swapped out
+	 */
+	if (adi_state.caps.nbits > 4) {
+		pr_warn("WARNING: ADI tag size >4 on this platform. Disabling AADI support\n");
+		adi_state.enabled = false;
+	}
+
+	mdesc_release(hp);
+	return;
+
+adi_not_found:
+	adi_state.enabled = false;
+	adi_state.caps.blksz = 0;
+	adi_state.caps.nbits = 0;
+	if (hp)
+		mdesc_release(hp);
+}
+
+tag_storage_desc_t *find_tag_store(struct mm_struct *mm,
+				   struct vm_area_struct *vma,
+				   unsigned long addr)
+{
+	tag_storage_desc_t *tag_desc = NULL;
+	unsigned long i, max_desc, flags;
+
+	/* Check if this vma already has tag storage descriptor
+	 * allocated for it.
+	 */
+	max_desc = PAGE_SIZE/sizeof(tag_storage_desc_t);
+	if (mm->context.tag_store) {
+		tag_desc = mm->context.tag_store;
+		spin_lock_irqsave(&mm->context.tag_lock, flags);
+		for (i = 0; i < max_desc; i++) {
+			if ((addr >= tag_desc->start) &&
+			    ((addr + PAGE_SIZE - 1) <= tag_desc->end))
+				break;
+			tag_desc++;
+		}
+		spin_unlock_irqrestore(&mm->context.tag_lock, flags);
+
+		/* If no matching entries were found, this must be a
+		 * freshly allocated page
+		 */
+		if (i >= max_desc)
+			tag_desc = NULL;
+	}
+
+	return tag_desc;
+}
+
+tag_storage_desc_t *alloc_tag_store(struct mm_struct *mm,
+				    struct vm_area_struct *vma,
+				    unsigned long addr)
+{
+	unsigned char *tags;
+	unsigned long i, size, max_desc, flags;
+	tag_storage_desc_t *tag_desc, *open_desc;
+	unsigned long end_addr, hole_start, hole_end;
+
+	max_desc = PAGE_SIZE/sizeof(tag_storage_desc_t);
+	open_desc = NULL;
+	hole_start = 0;
+	hole_end = ULONG_MAX;
+	end_addr = addr + PAGE_SIZE - 1;
+
+	/* Check if this vma already has tag storage descriptor
+	 * allocated for it.
+	 */
+	spin_lock_irqsave(&mm->context.tag_lock, flags);
+	if (mm->context.tag_store) {
+		tag_desc = mm->context.tag_store;
+
+		/* Look for a matching entry for this address. While doing
+		 * that, look for the first open slot as well and find
+		 * the hole in already allocated range where this request
+		 * will fit in.
+		 */
+		for (i = 0; i < max_desc; i++) {
+			if (tag_desc->tag_users == 0) {
+				if (open_desc == NULL)
+					open_desc = tag_desc;
+			} else {
+				if ((addr >= tag_desc->start) &&
+				    (tag_desc->end >= (addr + PAGE_SIZE - 1))) {
+					tag_desc->tag_users++;
+					goto out;
+				}
+			}
+			if ((tag_desc->start > end_addr) &&
+			    (tag_desc->start < hole_end))
+				hole_end = tag_desc->start;
+			if ((tag_desc->end < addr) &&
+			    (tag_desc->end > hole_start))
+				hole_start = tag_desc->end;
+			tag_desc++;
+		}
+
+	} else {
+		size = sizeof(tag_storage_desc_t)*max_desc;
+		mm->context.tag_store = kzalloc(size, GFP_NOWAIT|__GFP_NOWARN);
+		if (mm->context.tag_store == NULL) {
+			tag_desc = NULL;
+			goto out;
+		}
+		tag_desc = mm->context.tag_store;
+		for (i = 0; i < max_desc; i++, tag_desc++)
+			tag_desc->tag_users = 0;
+		open_desc = mm->context.tag_store;
+		i = 0;
+	}
+
+	/* Check if we ran out of tag storage descriptors */
+	if (open_desc == NULL) {
+		tag_desc = NULL;
+		goto out;
+	}
+
+	/* Mark this tag descriptor slot in use and then initialize it */
+	tag_desc = open_desc;
+	tag_desc->tag_users = 1;
+
+	/* Tag storage has not been allocated for this vma and space
+	 * is available in tag storage descriptor. Since this page is
+	 * being swapped out, there is high probability subsequent pages
+	 * in the VMA will be swapped out as well. Allocate pages to
+	 * store tags for as many pages in this vma as possible but not
+	 * more than TAG_STORAGE_PAGES. Each byte in tag space holds
+	 * two ADI tags since each ADI tag is 4 bits. Each ADI tag
+	 * covers adi_blksize() worth of addresses. Check if the hole is
+	 * big enough to accommodate full address range for using
+	 * TAG_STORAGE_PAGES number of tag pages.
+	 */
+	size = TAG_STORAGE_PAGES * PAGE_SIZE;
+	end_addr = addr + (size*2*adi_blksize()) - 1;
+	/* Check for overflow. If overflow occurs, allocate only one page */
+	if (end_addr < addr) {
+		size = PAGE_SIZE;
+		end_addr = addr + (size*2*adi_blksize()) - 1;
+		/* If overflow happens with the minimum tag storage
+		 * allocation as well, adjust ending address for this
+		 * tag storage.
+		 */
+		if (end_addr < addr)
+			end_addr = ULONG_MAX;
+	}
+	if (hole_end < end_addr) {
+		/* Available hole is too small on the upper end of
+		 * address. Can we expand the range towards the lower
+		 * address and maximize use of this slot?
+		 */
+		unsigned long tmp_addr;
+
+		end_addr = hole_end - 1;
+		tmp_addr = end_addr - (size*2*adi_blksize()) + 1;
+		/* Check for underflow. If underflow occurs, allocate
+		 * only one page for storing ADI tags
+		 */
+		if (tmp_addr > addr) {
+			size = PAGE_SIZE;
+			tmp_addr = end_addr - (size*2*adi_blksize()) - 1;
+			/* If underflow happens with the minimum tag storage
+			 * allocation as well, adjust starting address for
+			 * this tag storage.
+			 */
+			if (tmp_addr > addr)
+				tmp_addr = 0;
+		}
+		if (tmp_addr < hole_start) {
+			/* Available hole is restricted on lower address
+			 * end as well
+			 */
+			tmp_addr = hole_start + 1;
+		}
+		addr = tmp_addr;
+		size = (end_addr + 1 - addr)/(2*adi_blksize());
+		size = (size + (PAGE_SIZE-adi_blksize()))/PAGE_SIZE;
+		size = size * PAGE_SIZE;
+	}
+	tags = kzalloc(size, GFP_NOWAIT|__GFP_NOWARN);
+	if (tags == NULL) {
+		tag_desc->tag_users = 0;
+		tag_desc = NULL;
+		goto out;
+	}
+	tag_desc->start = addr;
+	tag_desc->tags = tags;
+	tag_desc->end = end_addr;
+
+out:
+	spin_unlock_irqrestore(&mm->context.tag_lock, flags);
+	return tag_desc;
+}
+
+void del_tag_store(tag_storage_desc_t *tag_desc, struct mm_struct *mm)
+{
+	unsigned long flags;
+	unsigned char *tags = NULL;
+
+	spin_lock_irqsave(&mm->context.tag_lock, flags);
+	tag_desc->tag_users--;
+	if (tag_desc->tag_users == 0) {
+		tag_desc->start = tag_desc->end = 0;
+		/* Do not free up the tag storage space allocated
+		 * by the first descriptor. This is persistent
+		 * emergency tag storage space for the task.
+		 */
+		if (tag_desc != mm->context.tag_store) {
+			tags = tag_desc->tags;
+			tag_desc->tags = NULL;
+		}
+	}
+	spin_unlock_irqrestore(&mm->context.tag_lock, flags);
+	kfree(tags);
+}
+
+#define tag_start(addr, tag_desc)		\
+	((tag_desc)->tags + ((addr - (tag_desc)->start)/(2*adi_blksize())))
+
+/* Retrieve any saved ADI tags for the page being swapped back in and
+ * restore these tags to the newly allocated physical page.
+ */
+void adi_restore_tags(struct mm_struct *mm, struct vm_area_struct *vma,
+		      unsigned long addr, pte_t pte)
+{
+	unsigned char *tag;
+	tag_storage_desc_t *tag_desc;
+	unsigned long paddr, tmp, version1, version2;
+
+	/* Check if the swapped out page has an ADI version
+	 * saved. If yes, restore version tag to the newly
+	 * allocated page.
+	 */
+	tag_desc = find_tag_store(mm, vma, addr);
+	if (tag_desc == NULL)
+		return;
+
+	tag = tag_start(addr, tag_desc);
+	paddr = pte_val(pte) & _PAGE_PADDR_4V;
+	for (tmp = paddr; tmp < (paddr+PAGE_SIZE); tmp += adi_blksize()) {
+		version1 = (*tag) >> 4;
+		version2 = (*tag) & 0x0f;
+		*tag++ = 0;
+		asm volatile("stxa %0, [%1] %2\n\t"
+			:
+			: "r" (version1), "r" (tmp),
+			  "i" (ASI_MCD_REAL));
+		tmp += adi_blksize();
+		asm volatile("stxa %0, [%1] %2\n\t"
+			:
+			: "r" (version2), "r" (tmp),
+			  "i" (ASI_MCD_REAL));
+	}
+	asm volatile("membar #Sync\n\t");
+
+	/* Check and mark this tag space for release later if
+	 * the swapped in page was the last user of tag space
+	 */
+	del_tag_store(tag_desc, mm);
+}
+
+/* A page is about to be swapped out. Save any ADI tags associated with
+ * this physical page so they can be restored later when the page is swapped
+ * back in.
+ */
+int adi_save_tags(struct mm_struct *mm, struct vm_area_struct *vma,
+		  unsigned long addr, pte_t oldpte)
+{
+	unsigned char *tag;
+	tag_storage_desc_t *tag_desc;
+	unsigned long version1, version2, paddr, tmp;
+
+	tag_desc = alloc_tag_store(mm, vma, addr);
+	if (tag_desc == NULL)
+		return -1;
+
+	tag = tag_start(addr, tag_desc);
+	paddr = pte_val(oldpte) & _PAGE_PADDR_4V;
+	for (tmp = paddr; tmp < (paddr+PAGE_SIZE); tmp += adi_blksize()) {
+		asm volatile("ldxa [%1] %2, %0\n\t"
+				: "=r" (version1)
+				: "r" (tmp), "i" (ASI_MCD_REAL));
+		tmp += adi_blksize();
+		asm volatile("ldxa [%1] %2, %0\n\t"
+				: "=r" (version2)
+				: "r" (tmp), "i" (ASI_MCD_REAL));
+		*tag = (version1 << 4) | version2;
+		tag++;
+	}
+
+	return 0;
+}
diff --git a/arch/sparc/kernel/entry.h b/arch/sparc/kernel/entry.h
index 7378567b601f..c746c0fd5d6b 100644
--- a/arch/sparc/kernel/entry.h
+++ b/arch/sparc/kernel/entry.h
@@ -160,6 +160,9 @@ void sun4v_resum_overflow(struct pt_regs *regs);
 void sun4v_nonresum_error(struct pt_regs *regs,
 			  unsigned long offset);
 void sun4v_nonresum_overflow(struct pt_regs *regs);
+void sun4v_mem_corrupt_detect_precise(struct pt_regs *regs,
+				      unsigned long addr,
+				      unsigned long context);
 
 extern unsigned long sun4v_err_itlb_vaddr;
 extern unsigned long sun4v_err_itlb_ctx;
diff --git a/arch/sparc/kernel/etrap_64.S b/arch/sparc/kernel/etrap_64.S
index 5c77a2e0e991..08cc41f64725 100644
--- a/arch/sparc/kernel/etrap_64.S
+++ b/arch/sparc/kernel/etrap_64.S
@@ -151,7 +151,32 @@ etrap_save:	save	%g2, -STACK_BIAS, %sp
 		stx	%g6, [%sp + PTREGS_OFF + PT_V9_G6]
 		stx	%g7, [%sp + PTREGS_OFF + PT_V9_G7]
 		or	%l7, %l0, %l7
-		sethi	%hi(TSTATE_TSO | TSTATE_PEF), %l0
+661:		sethi	%hi(TSTATE_TSO | TSTATE_PEF), %l0
+		/* If userspace is using ADI, it could potentially pass
+		 * a pointer with version tag embedded in it. To maintain
+		 * the ADI security, we must enable PSTATE.mcde. Userspace
+		 * would have already set TTE.mcd in an earlier call to
+		 * kernel and set the version tag for the address being
+		 * dereferenced. Setting PSTATE.mcde would ensure any
+		 * access to userspace data through a system call honors
+		 * ADI and does not allow a rogue app to bypass ADI by
+		 * using system calls. Setting PSTATE.mcde only affects
+		 * accesses to virtual addresses that have TTE.mcd set.
+		 * Set PMCDPER to ensure any exceptions caused by ADI
+		 * version tag mismatch are exposed before system call
+		 * returns to userspace. Setting PMCDPER affects only
+		 * writes to virtual addresses that have TTE.mcd set and
+		 * have a version tag set as well.
+		 */
+		.section .sun_m7_1insn_patch, "ax"
+		.word	661b
+		sethi	%hi(TSTATE_TSO | TSTATE_PEF | TSTATE_MCDE), %l0
+		.previous
+661:		nop
+		.section .sun_m7_1insn_patch, "ax"
+		.word	661b
+		.word 0xaf902001	/* wrpr %g0, 1, %pmcdper */
+		.previous
 		or	%l7, %l0, %l7
 		wrpr	%l2, %tnpc
 		wrpr	%l7, (TSTATE_PRIV | TSTATE_IE), %tstate
diff --git a/arch/sparc/kernel/head_64.S b/arch/sparc/kernel/head_64.S
index a41e6e16eb36..540bfc98472c 100644
--- a/arch/sparc/kernel/head_64.S
+++ b/arch/sparc/kernel/head_64.S
@@ -897,6 +897,7 @@ sparc64_boot_end:
 #include "syscalls.S"
 #include "helpers.S"
 #include "sun4v_tlb_miss.S"
+#include "sun4v_mcd.S"
 #include "sun4v_ivec.S"
 #include "ktlb.S"
 #include "tsb.S"
diff --git a/arch/sparc/kernel/mdesc.c b/arch/sparc/kernel/mdesc.c
index 418592a09b41..39a2503fa3e1 100644
--- a/arch/sparc/kernel/mdesc.c
+++ b/arch/sparc/kernel/mdesc.c
@@ -22,6 +22,7 @@
 #include <linux/uaccess.h>
 #include <asm/oplib.h>
 #include <asm/smp.h>
+#include <asm/adi.h>
 
 /* Unlike the OBP device tree, the machine description is a full-on
  * DAG.  An arbitrary number of ARCs are possible from one
@@ -1345,5 +1346,6 @@ void __init sun4v_mdesc_init(void)
 
 	cur_mdesc = hp;
 
+	mdesc_adi_init();
 	report_platform_properties();
 }
diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c
index 318efd784a0b..454a8af28f13 100644
--- a/arch/sparc/kernel/process_64.c
+++ b/arch/sparc/kernel/process_64.c
@@ -670,6 +670,31 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
 	return 0;
 }
 
+/* TIF_MCDPER in thread info flags for current task is updated lazily upon
+ * a context switch. Update this flag in current task's thread flags
+ * before dup so the dup'd task will inherit the current TIF_MCDPER flag.
+ */
+int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
+{
+	if (adi_capable()) {
+		register unsigned long tmp_mcdper;
+
+		__asm__ __volatile__(
+			".word 0x83438000\n\t"	/* rd  %mcdper, %g1 */
+			"mov %%g1, %0\n\t"
+			: "=r" (tmp_mcdper)
+			:
+			: "g1");
+		if (tmp_mcdper)
+			set_thread_flag(TIF_MCDPER);
+		else
+			clear_thread_flag(TIF_MCDPER);
+	}
+
+	*dst = *src;
+	return 0;
+}
+
 typedef struct {
 	union {
 		unsigned int	pr_regs[32];
diff --git a/arch/sparc/kernel/rtrap_64.S b/arch/sparc/kernel/rtrap_64.S
index 0b21042ab181..f6528884a2c8 100644
--- a/arch/sparc/kernel/rtrap_64.S
+++ b/arch/sparc/kernel/rtrap_64.S
@@ -25,13 +25,31 @@
 		.align			32
 __handle_preemption:
 		call			SCHEDULE_USER
-		 wrpr			%g0, RTRAP_PSTATE, %pstate
+661:		 wrpr			%g0, RTRAP_PSTATE, %pstate
+		/* If userspace is using ADI, it could potentially pass
+		 * a pointer with version tag embedded in it. To maintain
+		 * the ADI security, we must re-enable PSTATE.mcde before
+		 * we continue execution in the kernel for another thread.
+		 */
+		.section .sun_m7_1insn_patch, "ax"
+		.word	661b
+		 wrpr			%g0, RTRAP_PSTATE|PSTATE_MCDE, %pstate
+		.previous
 		ba,pt			%xcc, __handle_preemption_continue
 		 wrpr			%g0, RTRAP_PSTATE_IRQOFF, %pstate
 
 __handle_user_windows:
 		call			fault_in_user_windows
-		 wrpr			%g0, RTRAP_PSTATE, %pstate
+661:		 wrpr			%g0, RTRAP_PSTATE, %pstate
+		/* If userspace is using ADI, it could potentially pass
+		 * a pointer with version tag embedded in it. To maintain
+		 * the ADI security, we must re-enable PSTATE.mcde before
+		 * we continue execution in the kernel for another thread.
+		 */
+		.section .sun_m7_1insn_patch, "ax"
+		.word	661b
+		 wrpr			%g0, RTRAP_PSTATE|PSTATE_MCDE, %pstate
+		.previous
 		ba,pt			%xcc, __handle_preemption_continue
 		 wrpr			%g0, RTRAP_PSTATE_IRQOFF, %pstate
 
@@ -48,7 +66,16 @@ __handle_signal:
 		add			%sp, PTREGS_OFF, %o0
 		mov			%l0, %o2
 		call			do_notify_resume
-		 wrpr			%g0, RTRAP_PSTATE, %pstate
+661:		 wrpr			%g0, RTRAP_PSTATE, %pstate
+		/* If userspace is using ADI, it could potentially pass
+		 * a pointer with version tag embedded in it. To maintain
+		 * the ADI security, we must re-enable PSTATE.mcde before
+		 * we continue execution in the kernel for another thread.
+		 */
+		.section .sun_m7_1insn_patch, "ax"
+		.word	661b
+		 wrpr			%g0, RTRAP_PSTATE|PSTATE_MCDE, %pstate
+		.previous
 		wrpr			%g0, RTRAP_PSTATE_IRQOFF, %pstate
 
 		/* Signal delivery can modify pt_regs tstate, so we must
diff --git a/arch/sparc/kernel/setup_64.c b/arch/sparc/kernel/setup_64.c
index 34f7a533a74f..7944b3ca216a 100644
--- a/arch/sparc/kernel/setup_64.c
+++ b/arch/sparc/kernel/setup_64.c
@@ -294,6 +294,8 @@ static void __init sun4v_patch(void)
 	case SUN4V_CHIP_SPARC_M7:
 	case SUN4V_CHIP_SPARC_M8:
 	case SUN4V_CHIP_SPARC_SN:
+		sun4v_patch_1insn_range(&__sun_m7_1insn_patch,
+					&__sun_m7_1insn_patch_end);
 		sun_m7_patch_2insn_range(&__sun_m7_2insn_patch,
 					 &__sun_m7_2insn_patch_end);
 		break;
diff --git a/arch/sparc/kernel/sun4v_mcd.S b/arch/sparc/kernel/sun4v_mcd.S
new file mode 100644
index 000000000000..d6c69ebca110
--- /dev/null
+++ b/arch/sparc/kernel/sun4v_mcd.S
@@ -0,0 +1,18 @@
+/* sun4v_mcd.S: Sun4v memory corruption detected precise exception handler
+ *
+ * Copyright (c) 2015 Oracle and/or its affiliates. All rights reserved.
+ * Authors: Bob Picco <bob.picco@oracle.com>,
+ *          Khalid Aziz <khalid.aziz@oracle.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ */
+	.text
+	.align 32
+
+sun4v_mcd_detect_precise:
+	mov	%l4, %o1
+	mov 	%l5, %o2
+	call	sun4v_mem_corrupt_detect_precise
+	 add	%sp, PTREGS_OFF, %o0
+	ba,a,pt	%xcc, rtrap
+	 nop
diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index 0a56dc257cb9..462a21abd105 100644
--- a/arch/sparc/kernel/traps_64.c
+++ b/arch/sparc/kernel/traps_64.c
@@ -362,7 +362,6 @@ void sun4v_data_access_exception(struct pt_regs *regs, unsigned long addr, unsig
 {
 	unsigned short type = (type_ctx >> 16);
 	unsigned short ctx  = (type_ctx & 0xffff);
-	siginfo_t info;
 
 	if (notify_die(DIE_TRAP, "data access exception", regs,
 		       0, 0x8, SIGTRAP) == NOTIFY_STOP)
@@ -397,12 +396,29 @@ void sun4v_data_access_exception(struct pt_regs *regs, unsigned long addr, unsig
 	if (is_no_fault_exception(regs))
 		return;
 
-	info.si_signo = SIGSEGV;
-	info.si_errno = 0;
-	info.si_code = SEGV_MAPERR;
-	info.si_addr = (void __user *) addr;
-	info.si_trapno = 0;
-	force_sig_info(SIGSEGV, &info, current);
+	/* MCD (Memory Corruption Detection) disabled trap (TT=0x19) in HV
+	 * is vectored thorugh data access exception trap with fault type
+	 * set to HV_FAULT_TYPE_MCD_DIS. Check for MCD disabled trap.
+	 * Accessing an address with invalid ASI for the address, for
+	 * example setting an ADI tag on an address with ASI_MCD_PRIMARY
+	 * when TTE.mcd is not set for the VA, is also vectored into
+	 * kerbel by HV as data access exception with fault type set to
+	 * HV_FAULT_TYPE_INV_ASI.
+	 */
+	switch (type) {
+	case HV_FAULT_TYPE_INV_ASI:
+		force_sig_fault(SIGILL, ILL_ILLADR, (void __user *)addr, 0,
+				current);
+		break;
+	case HV_FAULT_TYPE_MCD_DIS:
+		force_sig_fault(SIGSEGV, SEGV_ACCADI, (void __user *)addr, 0,
+				current);
+		break;
+	default:
+		force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *)addr, 0,
+				current);
+		break;
+	}
 }
 
 void sun4v_data_access_exception_tl1(struct pt_regs *regs, unsigned long addr, unsigned long type_ctx)
@@ -1847,6 +1863,7 @@ struct sun4v_error_entry {
 #define SUN4V_ERR_ATTRS_ASI		0x00000080
 #define SUN4V_ERR_ATTRS_PRIV_REG	0x00000100
 #define SUN4V_ERR_ATTRS_SPSTATE_MSK	0x00000600
+#define SUN4V_ERR_ATTRS_MCD		0x00000800
 #define SUN4V_ERR_ATTRS_SPSTATE_SHFT	9
 #define SUN4V_ERR_ATTRS_MODE_MSK	0x03000000
 #define SUN4V_ERR_ATTRS_MODE_SHFT	24
@@ -2044,6 +2061,50 @@ static void sun4v_log_error(struct pt_regs *regs, struct sun4v_error_entry *ent,
 	}
 }
 
+/* Handle memory corruption detected error which is vectored in
+ * through resumable error trap.
+ */
+void do_mcd_err(struct pt_regs *regs, struct sun4v_error_entry ent)
+{
+	if (notify_die(DIE_TRAP, "MCD error", regs, 0, 0x34,
+		       SIGSEGV) == NOTIFY_STOP)
+		return;
+
+	if (regs->tstate & TSTATE_PRIV) {
+		/* MCD exception could happen because the task was
+		 * running a system call with MCD enabled and passed a
+		 * non-versioned pointer or pointer with bad version
+		 * tag to the system call. In such cases, hypervisor
+		 * places the address of offending instruction in the
+		 * resumable error report. This is a deferred error,
+		 * so the read/write that caused the trap was potentially
+		 * retired long time back and we may have no choice
+		 * but to send SIGSEGV to the process.
+		 */
+		const struct exception_table_entry *entry;
+
+		entry = search_exception_tables(regs->tpc);
+		if (entry) {
+			/* Looks like a bad syscall parameter */
+#ifdef DEBUG_EXCEPTIONS
+			pr_emerg("Exception: PC<%016lx> faddr<UNKNOWN>\n",
+				 regs->tpc);
+			pr_emerg("EX_TABLE: insn<%016lx> fixup<%016lx>\n",
+				 ent.err_raddr, entry->fixup);
+#endif
+			regs->tpc = entry->fixup;
+			regs->tnpc = regs->tpc + 4;
+			return;
+		}
+	}
+
+	/* Send SIGSEGV to the userspace process with the right signal
+	 * code
+	 */
+	force_sig_fault(SIGSEGV, SEGV_ADIDERR, (void __user *)ent.err_raddr,
+			0, current);
+}
+
 /* We run with %pil set to PIL_NORMAL_MAX and PSTATE_IE enabled in %pstate.
  * Log the event and clear the first word of the entry.
  */
@@ -2081,6 +2142,14 @@ void sun4v_resum_error(struct pt_regs *regs, unsigned long offset)
 		goto out;
 	}
 
+	/* If this is a memory corruption detected error vectored in
+	 * by HV through resumable error trap, call the handler
+	 */
+	if (local_copy.err_attrs & SUN4V_ERR_ATTRS_MCD) {
+		do_mcd_err(regs, local_copy);
+		return;
+	}
+
 	sun4v_log_error(regs, &local_copy, cpu,
 			KERN_ERR "RESUMABLE ERROR",
 			&sun4v_resum_oflow_cnt);
@@ -2656,6 +2725,53 @@ void sun4v_do_mna(struct pt_regs *regs, unsigned long addr, unsigned long type_c
 	force_sig_info(SIGBUS, &info, current);
 }
 
+/* sun4v_mem_corrupt_detect_precise() - Handle precise exception on an ADI
+ * tag mismatch.
+ *
+ * ADI version tag mismatch on a load from memory always results in a
+ * precise exception. Tag mismatch on a store to memory will result in
+ * precise exception if MCDPER or PMCDPER is set to 1.
+ */
+void sun4v_mem_corrupt_detect_precise(struct pt_regs *regs, unsigned long addr,
+				      unsigned long context)
+{
+	if (notify_die(DIE_TRAP, "memory corruption precise exception", regs,
+		       0, 0x8, SIGSEGV) == NOTIFY_STOP)
+		return;
+
+	if (regs->tstate & TSTATE_PRIV) {
+		/* MCD exception could happen because the task was running
+		 * a system call with MCD enabled and passed a non-versioned
+		 * pointer or pointer with bad version tag to  the system
+		 * call.
+		 */
+		const struct exception_table_entry *entry;
+
+		entry = search_exception_tables(regs->tpc);
+		if (entry) {
+			/* Looks like a bad syscall parameter */
+#ifdef DEBUG_EXCEPTIONS
+			pr_emerg("Exception: PC<%016lx> faddr<UNKNOWN>\n",
+				 regs->tpc);
+			pr_emerg("EX_TABLE: insn<%016lx> fixup<%016lx>\n",
+				 regs->tpc, entry->fixup);
+#endif
+			regs->tpc = entry->fixup;
+			regs->tnpc = regs->tpc + 4;
+			return;
+		}
+		pr_emerg("%s: ADDR[%016lx] CTX[%lx], going.\n",
+			 __func__, addr, context);
+		die_if_kernel("MCD precise", regs);
+	}
+
+	if (test_thread_flag(TIF_32BIT)) {
+		regs->tpc &= 0xffffffff;
+		regs->tnpc &= 0xffffffff;
+	}
+	force_sig_fault(SIGSEGV, SEGV_ADIPERR, (void __user *)addr, 0, current);
+}
+
 void do_privop(struct pt_regs *regs)
 {
 	enum ctx_state prev_state = exception_enter();
diff --git a/arch/sparc/kernel/ttable_64.S b/arch/sparc/kernel/ttable_64.S
index 18685fe69b91..86e737e59c7e 100644
--- a/arch/sparc/kernel/ttable_64.S
+++ b/arch/sparc/kernel/ttable_64.S
@@ -26,8 +26,10 @@ tl0_ill:	membar #Sync
 		TRAP_7INSNS(do_illegal_instruction)
 tl0_privop:	TRAP(do_privop)
 tl0_resv012:	BTRAP(0x12) BTRAP(0x13) BTRAP(0x14) BTRAP(0x15) BTRAP(0x16) BTRAP(0x17)
-tl0_resv018:	BTRAP(0x18) BTRAP(0x19) BTRAP(0x1a) BTRAP(0x1b) BTRAP(0x1c) BTRAP(0x1d)
-tl0_resv01e:	BTRAP(0x1e) BTRAP(0x1f)
+tl0_resv018:	BTRAP(0x18) BTRAP(0x19)
+tl0_mcd:	SUN4V_MCD_PRECISE
+tl0_resv01b:	BTRAP(0x1b)
+tl0_resv01c:	BTRAP(0x1c) BTRAP(0x1d)	BTRAP(0x1e) BTRAP(0x1f)
 tl0_fpdis:	TRAP_NOSAVE(do_fpdis)
 tl0_fpieee:	TRAP_SAVEFPU(do_fpieee)
 tl0_fpother:	TRAP_NOSAVE(do_fpother_check_fitos)
diff --git a/arch/sparc/kernel/urtt_fill.S b/arch/sparc/kernel/urtt_fill.S
index 44183aa59168..e4cee7be5cd0 100644
--- a/arch/sparc/kernel/urtt_fill.S
+++ b/arch/sparc/kernel/urtt_fill.S
@@ -50,7 +50,12 @@ user_rtt_fill_fixup_common:
 		SET_GL(0)
 		.previous
 
-		wrpr	%g0, RTRAP_PSTATE, %pstate
+661:		wrpr	%g0, RTRAP_PSTATE, %pstate
+		.section		.sun_m7_1insn_patch, "ax"
+		.word			661b
+		/* Re-enable PSTATE.mcde to maintain ADI security */
+		wrpr	%g0, RTRAP_PSTATE|PSTATE_MCDE, %pstate
+		.previous
 
 		mov	%l1, %g6
 		ldx	[%g6 + TI_TASK], %g4
diff --git a/arch/sparc/kernel/vmlinux.lds.S b/arch/sparc/kernel/vmlinux.lds.S
index 5a2344574f39..61afd787bd0c 100644
--- a/arch/sparc/kernel/vmlinux.lds.S
+++ b/arch/sparc/kernel/vmlinux.lds.S
@@ -145,6 +145,11 @@ SECTIONS
 		*(.pause_3insn_patch)
 		__pause_3insn_patch_end = .;
 	}
+	.sun_m7_1insn_patch : {
+		__sun_m7_1insn_patch = .;
+		*(.sun_m7_1insn_patch)
+		__sun_m7_1insn_patch_end = .;
+	}
 	.sun_m7_2insn_patch : {
 		__sun_m7_2insn_patch = .;
 		*(.sun_m7_2insn_patch)