[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 0d340720fd99..a1f153e89133 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 261785ab5b22..d480f39d65e6 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 d2b4ff831477..3b59216e6284 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 991ba939408c..32e8f6aa4384 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 000000000000..a44f4fe16a35
--- /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__ */