[PATCH] powerpc: Merge vdso's and add vdso support to 32 bits kernel

This patch moves the vdso's to arch/powerpc, adds support for the 32
bits vdso to the 32 bits kernel, rename systemcfg (finally !), and adds
some new (still untested) routines to both vdso's: clock_gettime() with
support for CLOCK_REALTIME and CLOCK_MONOTONIC, clock_getres() (same
clocks) and get_tbfreq() for glibc to retreive the timebase frequency.

Tom,Steve: The implementation of get_tbfreq() I've done for 32 bits
returns a long long (r3, r4) not a long. This is such that if we ever
add support for >4Ghz timebases on ppc32, the userland interface won't
have to change.

I have tested gettimeofday() using some glibc patches in both ppc32 and
ppc64 kernels using 32 bits userland (I haven't had a chance to test a
64 bits userland yet, but the implementation didn't change and was
tested earlier). I haven't tested yet the new functions.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

include/asm-powerpc/vdso_datapage.h

@@ -0,0 +1,108 @@
+#ifndef _VDSO_DATAPAGE_H
+#define _VDSO_DATAPAGE_H
+
+/*
+ * Copyright (C) 2002 Peter Bergner <bergner@vnet.ibm.com>, IBM
+ * Copyright (C) 2005 Benjamin Herrenschmidy <benh@kernel.crashing.org>,
+ * 		      IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+
+/*
+ * Note about this structure:
+ *
+ * This structure was historically called systemcfg and exposed to
+ * userland via /proc/ppc64/systemcfg. Unfortunately, this became an
+ * ABI issue as some proprietary software started relying on being able
+ * to mmap() it, thus we have to keep the base layout at least for a
+ * few kernel versions.
+ *
+ * However, since ppc32 doesn't suffer from this backward handicap,
+ * a simpler version of the data structure is used there with only the
+ * fields actually used by the vDSO.
+ *
+ */
+
+/*
+ * If the major version changes we are incompatible.
+ * Minor version changes are a hint.
+ */
+#define SYSTEMCFG_MAJOR 1
+#define SYSTEMCFG_MINOR 1
+
+#ifndef __ASSEMBLY__
+
+#include <linux/unistd.h>
+
+#define SYSCALL_MAP_SIZE      ((__NR_syscalls + 31) / 32)
+
+/*
+ * So here is the ppc64 backward compatible version
+ */
+
+#ifdef CONFIG_PPC64
+
+struct vdso_data {
+	__u8  eye_catcher[16];		/* Eyecatcher: SYSTEMCFG:PPC64	0x00 */
+	struct {			/* Systemcfg version numbers	     */
+		__u32 major;		/* Major number			0x10 */
+		__u32 minor;		/* Minor number			0x14 */
+	} version;
+
+	__u32 platform;			/* Platform flags		0x18 */
+	__u32 processor;		/* Processor type		0x1C */
+	__u64 processorCount;		/* # of physical processors	0x20 */
+	__u64 physicalMemorySize;	/* Size of real memory(B)	0x28 */
+	__u64 tb_orig_stamp;		/* Timebase at boot		0x30 */
+	__u64 tb_ticks_per_sec;		/* Timebase tics / sec		0x38 */
+	__u64 tb_to_xs;			/* Inverse of TB to 2^20	0x40 */
+	__u64 stamp_xsec;		/*				0x48 */
+	__u64 tb_update_count;		/* Timebase atomicity ctr	0x50 */
+	__u32 tz_minuteswest;		/* Minutes west of Greenwich	0x58 */
+	__u32 tz_dsttime;		/* Type of dst correction	0x5C */
+	__u32 dcache_size;		/* L1 d-cache size		0x60 */
+	__u32 dcache_line_size;		/* L1 d-cache line size		0x64 */
+	__u32 icache_size;		/* L1 i-cache size		0x68 */
+	__u32 icache_line_size;		/* L1 i-cache line size		0x6C */
+
+	/* those additional ones don't have to be located anywhere
+	 * special as they were not part of the original systemcfg
+	 */
+	__s64 wtom_clock_sec;			/* Wall to monotonic clock */
+	__s32 wtom_clock_nsec;
+   	__u32 syscall_map_64[SYSCALL_MAP_SIZE]; /* map of syscalls  */
+   	__u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */
+};
+
+#else /* CONFIG_PPC64 */
+
+/*
+ * And here is the simpler 32 bits version
+ */
+struct vdso_data {
+	__u64 tb_orig_stamp;		/* Timebase at boot		0x30 */
+	__u64 tb_ticks_per_sec;		/* Timebase tics / sec		0x38 */
+	__u64 tb_to_xs;			/* Inverse of TB to 2^20	0x40 */
+	__u64 stamp_xsec;		/*				0x48 */
+	__u32 tb_update_count;		/* Timebase atomicity ctr	0x50 */
+	__u32 tz_minuteswest;		/* Minutes west of Greenwich	0x58 */
+	__u32 tz_dsttime;		/* Type of dst correction	0x5C */
+	__s32 wtom_clock_sec;			/* Wall to monotonic clock */
+	__s32 wtom_clock_nsec;
+   	__u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */
+};
+
+#endif /* CONFIG_PPC64 */
+
+#ifdef __KERNEL__
+extern struct vdso_data *vdso_data;
+#endif
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _SYSTEMCFG_H */