summaryrefslogtreecommitdiffstats
path: root/arch/sparc/kernel/adi_64.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/sparc/kernel/adi_64.c')
-rw-r--r--arch/sparc/kernel/adi_64.c397
1 files changed, 397 insertions, 0 deletions
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;
+}