[S390] introduce vdso on s390

Add a vdso to speed up gettimeofday and clock_getres/clock_gettime for
CLOCK_REALTIME/CLOCK_MONOTONIC.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

5 files changed, 60 insertions, 0 deletions

diff --git a/arch/s390/include/asm/auxvec.h b/arch/s390/include/asm/auxvec.h
index 0d34072..a1f153e 100644
--- a/arch/s390/include/asm/auxvec.h
+++ b/arch/s390/include/asm/auxvec.h
@@ -1,4 +1,6 @@
 #ifndef __ASMS390_AUXVEC_H
 #define __ASMS390_AUXVEC_H
 
+#define AT_SYSINFO_EHDR		33
+
 #endif
diff --git a/arch/s390/include/asm/elf.h b/arch/s390/include/asm/elf.h
index 261785a..d480f39 100644
--- a/arch/s390/include/asm/elf.h
+++ b/arch/s390/include/asm/elf.h
@@ -120,6 +120,10 @@ typedef s390_compat_regs compat_elf_gregset_t;
 #include <asm/system.h>		/* for save_access_regs */
 #include <asm/mmu_context.h>
 
+#include <asm/vdso.h>
+
+extern unsigned int vdso_enabled;
+
 /*
  * This is used to ensure we don't load something for the wrong architecture.
  */
@@ -191,4 +195,16 @@ do {							\
 	current->mm->context.noexec == 0;		\
 })
 
+#define ARCH_DLINFO							    \
+do {									    \
+	if (vdso_enabled)						    \
+		NEW_AUX_ENT(AT_SYSINFO_EHDR,				    \
+			    (unsigned long)current->mm->context.vdso_base); \
+} while (0)
+
+struct linux_binprm;
+
+#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
+int arch_setup_additional_pages(struct linux_binprm *, int);
+
 #endif
diff --git a/arch/s390/include/asm/mmu.h b/arch/s390/include/asm/mmu.h
index d2b4ff8..3b59216 100644
--- a/arch/s390/include/asm/mmu.h
+++ b/arch/s390/include/asm/mmu.h
@@ -6,6 +6,7 @@ typedef struct {
 	struct list_head pgtable_list;
 	unsigned long asce_bits;
 	unsigned long asce_limit;
+	unsigned long vdso_base;
 	int noexec;
 	int has_pgste;	 /* The mmu context has extended page tables */
 	int alloc_pgste; /* cloned contexts will have extended page tables */
diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index 991ba93..32e8f6a 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -152,4 +152,6 @@ void arch_alloc_page(struct page *page, int order);
 #include <asm-generic/memory_model.h>
 #include <asm-generic/page.h>
 
+#define __HAVE_ARCH_GATE_AREA 1
+
 #endif /* _S390_PAGE_H */
diff --git a/arch/s390/include/asm/vdso.h b/arch/s390/include/asm/vdso.h
new file mode 100644
index 0000000..a44f4fe
--- /dev/null
+++ b/arch/s390/include/asm/vdso.h
@@ -0,0 +1,39 @@
+#ifndef __S390_VDSO_H__
+#define __S390_VDSO_H__
+
+#ifdef __KERNEL__
+
+/* Default link addresses for the vDSOs */
+#define VDSO32_LBASE	0
+#define VDSO64_LBASE	0
+
+#define VDSO_VERSION_STRING	LINUX_2.6.26
+
+#ifndef __ASSEMBLY__
+
+/*
+ * Note about this structure:
+ *
+ * NEVER USE THIS IN USERSPACE CODE DIRECTLY. The layout of this
+ * structure is supposed to be known only to the function in the vdso
+ * itself and may change without notice.
+ */
+
+struct vdso_data {
+	__u64 tb_update_count;		/* Timebase atomicity ctr	0x00 */
+	__u64 xtime_tod_stamp;		/* TOD clock for xtime		0x08 */
+	__u64 xtime_clock_sec;		/* Kernel time			0x10 */
+	__u64 xtime_clock_nsec;		/*				0x18 */
+	__u64 wtom_clock_sec;		/* Wall to monotonic clock	0x20 */
+	__u64 wtom_clock_nsec;		/*				0x28 */
+	__u32 tz_minuteswest;		/* Minutes west of Greenwich	0x30 */
+	__u32 tz_dsttime;		/* Type of dst correction	0x34 */
+};
+
+extern struct vdso_data *vdso_data;
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __KERNEL__ */
+
+#endif /* __S390_VDSO_H__ */