sparc64: Add support for ADI (Application Data Integrity)

ADI is a new feature supported on SPARC M7 and newer processors to allow
hardware to catch rogue accesses to memory. ADI is supported for data
fetches only and not instruction fetches. An app can enable ADI on its
data pages, set version tags on them and use versioned addresses to
access the data pages. Upper bits of the address contain the version
tag. On M7 processors, upper four bits (bits 63-60) contain the version
tag. If a rogue app attempts to access ADI enabled data pages, its
access is blocked and processor generates an exception. Please see
Documentation/sparc/adi.txt for further details.

This patch extends mprotect to enable ADI (TSTATE.mcde), enable/disable
MCD (Memory Corruption Detection) on selected memory ranges, enable
TTE.mcd in PTEs, return ADI parameters to userspace and save/restore ADI
version tags on page swap out/in or migration. ADI is not enabled by
default for any task. A task must explicitly enable ADI on a memory
range and set version tag for ADI to be effective for the task.

Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Khalid Aziz <khalid@gonehiking.org>
Reviewed-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 46 insertions, 0 deletions

diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 619332a44402..44d6ac47e035 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -19,6 +19,7 @@
 #include <asm/types.h>
 #include <asm/spitfire.h>
 #include <asm/asi.h>
+#include <asm/adi.h>
 #include <asm/page.h>
 #include <asm/processor.h>
 
@@ -606,6 +607,18 @@ static inline pte_t pte_mkspecial(pte_t pte)
 	return pte;
 }
 
+static inline pte_t pte_mkmcd(pte_t pte)
+{
+	pte_val(pte) |= _PAGE_MCD_4V;
+	return pte;
+}
+
+static inline pte_t pte_mknotmcd(pte_t pte)
+{
+	pte_val(pte) &= ~_PAGE_MCD_4V;
+	return pte;
+}
+
 static inline unsigned long pte_young(pte_t pte)
 {
 	unsigned long mask;
@@ -1048,6 +1061,39 @@ int page_in_phys_avail(unsigned long paddr);
 int remap_pfn_range(struct vm_area_struct *, unsigned long, unsigned long,
 		    unsigned long, pgprot_t);
 
+void adi_restore_tags(struct mm_struct *mm, struct vm_area_struct *vma,
+		      unsigned long addr, pte_t pte);
+
+int adi_save_tags(struct mm_struct *mm, struct vm_area_struct *vma,
+		  unsigned long addr, pte_t oldpte);
+
+#define __HAVE_ARCH_DO_SWAP_PAGE
+static inline void arch_do_swap_page(struct mm_struct *mm,
+				     struct vm_area_struct *vma,
+				     unsigned long addr,
+				     pte_t pte, pte_t oldpte)
+{
+	/* If this is a new page being mapped in, there can be no
+	 * ADI tags stored away for this page. Skip looking for
+	 * stored tags
+	 */
+	if (pte_none(oldpte))
+		return;
+
+	if (adi_state.enabled && (pte_val(pte) & _PAGE_MCD_4V))
+		adi_restore_tags(mm, vma, addr, pte);
+}
+
+#define __HAVE_ARCH_UNMAP_ONE
+static inline int arch_unmap_one(struct mm_struct *mm,
+				 struct vm_area_struct *vma,
+				 unsigned long addr, pte_t oldpte)
+{
+	if (adi_state.enabled && (pte_val(oldpte) & _PAGE_MCD_4V))
+		return adi_save_tags(mm, vma, addr, oldpte);
+	return 0;
+}
+
 static inline int io_remap_pfn_range(struct vm_area_struct *vma,
 				     unsigned long from, unsigned long pfn,
 				     unsigned long size, pgprot_t prot)