sparc64: Add auxiliary vectors to report platform ADI properties

ADI feature on M7 and newer processors has three important properties
relevant to userspace apps using ADI capabilities - (1) Size of block of
memory an ADI version tag applies to, (2) Number of uppermost bits in
virtual address used to encode ADI tag, and (3) The value M7 processor
will force the ADI tags to if it detects uncorrectable error in an ADI
tagged cacheline. Kernel can retrieve these properties for a platform
through machine description provided by the firmware. This patch adds
code to retrieve these properties and report them to userspace through
auxiliary vectors.

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>

3 files changed, 58 insertions, 0 deletions

diff --git a/arch/sparc/include/asm/adi.h b/arch/sparc/include/asm/adi.h
new file mode 100644
index 0000000..acad0d0
--- /dev/null
+++ b/arch/sparc/include/asm/adi.h
@@ -0,0 +1,6 @@
+#ifndef ___ASM_SPARC_ADI_H
+#define ___ASM_SPARC_ADI_H
+#if defined(__sparc__) && defined(__arch64__)
+#include <asm/adi_64.h>
+#endif
+#endif
diff --git a/arch/sparc/include/asm/adi_64.h b/arch/sparc/include/asm/adi_64.h
new file mode 100644
index 0000000..85f7a76
--- /dev/null
+++ b/arch/sparc/include/asm/adi_64.h
@@ -0,0 +1,47 @@
+/* adi_64.h: ADI related data structures
+ *
+ * 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.
+ */
+#ifndef __ASM_SPARC64_ADI_H
+#define __ASM_SPARC64_ADI_H
+
+#include <linux/types.h>
+
+#ifndef __ASSEMBLY__
+
+struct adi_caps {
+	__u64 blksz;
+	__u64 nbits;
+	__u64 ue_on_adi;
+};
+
+struct adi_config {
+	bool enabled;
+	struct adi_caps caps;
+};
+
+extern struct adi_config adi_state;
+
+extern void mdesc_adi_init(void);
+
+static inline bool adi_capable(void)
+{
+	return adi_state.enabled;
+}
+
+static inline unsigned long adi_blksize(void)
+{
+	return adi_state.caps.blksz;
+}
+
+static inline unsigned long adi_nbits(void)
+{
+	return adi_state.caps.nbits;
+}
+
+#endif	/* __ASSEMBLY__ */
+
+#endif	/* !(__ASM_SPARC64_ADI_H) */
diff --git a/arch/sparc/include/asm/elf_64.h b/arch/sparc/include/asm/elf_64.h
index 25340df..7e078bc 100644
--- a/arch/sparc/include/asm/elf_64.h
+++ b/arch/sparc/include/asm/elf_64.h
@@ -10,6 +10,7 @@
 #include <asm/processor.h>
 #include <asm/extable_64.h>
 #include <asm/spitfire.h>
+#include <asm/adi.h>
 
 /*
  * Sparc section types
@@ -215,9 +216,13 @@ extern unsigned int vdso_enabled;
 
 #define	ARCH_DLINFO							\
 do {									\
+	extern struct adi_config adi_state;				\
 	if (vdso_enabled)						\
 		NEW_AUX_ENT(AT_SYSINFO_EHDR,				\
 			    (unsigned long)current->mm->context.vdso);	\
+	NEW_AUX_ENT(AT_ADI_BLKSZ, adi_state.caps.blksz);		\
+	NEW_AUX_ENT(AT_ADI_NBITS, adi_state.caps.nbits);		\
+	NEW_AUX_ENT(AT_ADI_UEONADI, adi_state.caps.ue_on_adi);		\
 } while (0)
 
 struct linux_binprm;