Initial commit: Linux kernel 4.19 for Unplugged OS

include/vdso/bits.h

@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_BITS_H
+#define __VDSO_BITS_H
+
+#define BIT(nr)			(1UL << (nr))
+
+#endif	/* __VDSO_BITS_H */

include/vdso/clocksource.h

@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_CLOCKSOURCE_H
+#define __VDSO_CLOCKSOURCE_H
+
+#include <vdso/limits.h>
+
+#ifdef CONFIG_GENERIC_GETTIMEOFDAY
+#include <asm/vdso/clocksource.h>
+#endif /* CONFIG_GENERIC_GETTIMEOFDAY */
+
+enum vdso_clock_mode {
+	VDSO_CLOCKMODE_NONE,
+#ifdef CONFIG_GENERIC_GETTIMEOFDAY
+	VDSO_ARCH_CLOCKMODES,
+#endif
+	VDSO_CLOCKMODE_MAX,
+
+	/* Indicator for time namespace VDSO */
+	VDSO_CLOCKMODE_TIMENS = INT_MAX
+};
+
+#endif /* __VDSO_CLOCKSOURCE_H */

include/vdso/const.h

@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_CONST_H
+#define __VDSO_CONST_H
+
+#include <uapi/linux/const.h>
+
+#define UL(x)		(_UL(x))
+#define ULL(x)		(_ULL(x))
+
+#endif /* __VDSO_CONST_H */

include/vdso/datapage.h

@@ -0,0 +1,117 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_DATAPAGE_H
+#define __VDSO_DATAPAGE_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/compiler.h>
+#include <linux/compat_time.h>
+#include <uapi/linux/time.h>
+#include <uapi/linux/types.h>
+#include <uapi/asm-generic/errno-base.h>
+
+#include <vdso/bits.h>
+#include <vdso/clocksource.h>
+#include <vdso/ktime.h>
+#include <vdso/limits.h>
+#include <vdso/math64.h>
+#include <vdso/processor.h>
+#include <vdso/time.h>
+#include <vdso/time32.h>
+#include <vdso/time64.h>
+
+#define VDSO_BASES	(CLOCK_TAI + 1)
+#define VDSO_HRES	(BIT(CLOCK_REALTIME)		| \
+			 BIT(CLOCK_MONOTONIC)		| \
+			 BIT(CLOCK_BOOTTIME)		| \
+			 BIT(CLOCK_TAI))
+#define VDSO_COARSE	(BIT(CLOCK_REALTIME_COARSE)	| \
+			 BIT(CLOCK_MONOTONIC_COARSE))
+#define VDSO_RAW	(BIT(CLOCK_MONOTONIC_RAW))
+
+#define CS_HRES_COARSE	0
+#define CS_RAW		1
+#define CS_BASES	(CS_RAW + 1)
+
+/**
+ * struct vdso_timestamp - basetime per clock_id
+ * @sec:	seconds
+ * @nsec:	nanoseconds
+ *
+ * There is one vdso_timestamp object in vvar for each vDSO-accelerated
+ * clock_id. For high-resolution clocks, this encodes the time
+ * corresponding to vdso_data.cycle_last. For coarse clocks this encodes
+ * the actual time.
+ *
+ * To be noticed that for highres clocks nsec is left-shifted by
+ * vdso_data.cs[x].shift.
+ */
+struct vdso_timestamp {
+	u64	sec;
+	u64	nsec;
+};
+
+/**
+ * struct vdso_data - vdso datapage representation
+ * @seq:		timebase sequence counter
+ * @clock_mode:		clock mode
+ * @cycle_last:		timebase at clocksource init
+ * @mask:		clocksource mask
+ * @mult:		clocksource multiplier
+ * @shift:		clocksource shift
+ * @basetime[clock_id]:	basetime per clock_id
+ * @tz_minuteswest:	minutes west of Greenwich
+ * @tz_dsttime:		type of DST correction
+ * @hrtimer_res:	hrtimer resolution
+ * @__unused:		unused
+ *
+ * vdso_data will be accessed by 64 bit and compat code at the same time
+ * so we should be careful before modifying this structure.
+ */
+struct vdso_data {
+	u32			seq;
+
+	s32			clock_mode;
+	u64			cycle_last;
+	u64			mask;
+	u32			mult;
+	u32			shift;
+
+	struct vdso_timestamp	basetime[VDSO_BASES];
+
+	s32			tz_minuteswest;
+	s32			tz_dsttime;
+	u32			hrtimer_res;
+	u32			__unused;
+};
+
+/*
+ * We use the hidden visibility to prevent the compiler from generating a GOT
+ * relocation. Not only is going through a GOT useless (the entry couldn't and
+ * must not be overridden by another library), it does not even work: the linker
+ * cannot generate an absolute address to the data page.
+ *
+ * With the hidden visibility, the compiler simply generates a PC-relative
+ * relocation, and this is what we need.
+ */
+extern struct vdso_data _vdso_data[CS_BASES] __attribute__((visibility("hidden")));
+
+/*
+ * The generic vDSO implementation requires that gettimeofday.h
+ * provides:
+ * - __arch_get_vdso_data(): to get the vdso datapage.
+ * - __arch_get_hw_counter(): to get the hw counter based on the
+ *   clock_mode.
+ * - gettimeofday_fallback(): fallback for gettimeofday.
+ * - clock_gettime_fallback(): fallback for clock_gettime.
+ * - clock_getres_fallback(): fallback for clock_getres.
+ */
+#ifdef ENABLE_COMPAT_VDSO
+#include <asm/vdso/compat_gettimeofday.h>
+#else
+#include <asm/vdso/gettimeofday.h>
+#endif /* ENABLE_COMPAT_VDSO */
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __VDSO_DATAPAGE_H */

include/vdso/helpers.h

@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_HELPERS_H
+#define __VDSO_HELPERS_H
+
+#ifndef __ASSEMBLY__
+
+#include <vdso/datapage.h>
+
+static __always_inline u32 vdso_read_begin(const struct vdso_data *vd)
+{
+	u32 seq;
+
+	while ((seq = READ_ONCE(vd->seq)) & 1)
+		cpu_relax();
+
+	smp_rmb();
+	return seq;
+}
+
+static __always_inline u32 vdso_read_retry(const struct vdso_data *vd,
+					   u32 start)
+{
+	u32 seq;
+
+	smp_rmb();
+	seq = READ_ONCE(vd->seq);
+	return seq != start;
+}
+
+static __always_inline void vdso_write_begin(struct vdso_data *vd)
+{
+	/*
+	 * WRITE_ONCE it is required otherwise the compiler can validly tear
+	 * updates to vd[x].seq and it is possible that the value seen by the
+	 * reader it is inconsistent.
+	 */
+	WRITE_ONCE(vd[CS_HRES_COARSE].seq, vd[CS_HRES_COARSE].seq + 1);
+	WRITE_ONCE(vd[CS_RAW].seq, vd[CS_RAW].seq + 1);
+	smp_wmb();
+}
+
+static __always_inline void vdso_write_end(struct vdso_data *vd)
+{
+	smp_wmb();
+	/*
+	 * WRITE_ONCE it is required otherwise the compiler can validly tear
+	 * updates to vd[x].seq and it is possible that the value seen by the
+	 * reader it is inconsistent.
+	 */
+	WRITE_ONCE(vd[CS_HRES_COARSE].seq, vd[CS_HRES_COARSE].seq + 1);
+	WRITE_ONCE(vd[CS_RAW].seq, vd[CS_RAW].seq + 1);
+}
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __VDSO_HELPERS_H */

include/vdso/jiffies.h

@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_JIFFIES_H
+#define __VDSO_JIFFIES_H
+
+#include <asm/param.h>			/* for HZ */
+#include <vdso/time64.h>
+
+/* TICK_NSEC is the time between ticks in nsec assuming SHIFTED_HZ */
+#define TICK_NSEC ((NSEC_PER_SEC+HZ/2)/HZ)
+
+#endif /* __VDSO_JIFFIES_H */

include/vdso/ktime.h

@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_KTIME_H
+#define __VDSO_KTIME_H
+
+#include <vdso/jiffies.h>
+
+/*
+ * The resolution of the clocks. The resolution value is returned in
+ * the clock_getres() system call to give application programmers an
+ * idea of the (in)accuracy of timers. Timer values are rounded up to
+ * this resolution values.
+ */
+#define LOW_RES_NSEC		TICK_NSEC
+#define KTIME_LOW_RES		(LOW_RES_NSEC)
+
+#endif /* __VDSO_KTIME_H */

include/vdso/limits.h

@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_LIMITS_H
+#define __VDSO_LIMITS_H
+
+#define USHRT_MAX	((unsigned short)~0U)
+#define SHRT_MAX	((short)(USHRT_MAX >> 1))
+#define SHRT_MIN	((short)(-SHRT_MAX - 1))
+#define INT_MAX		((int)(~0U >> 1))
+#define INT_MIN		(-INT_MAX - 1)
+#define UINT_MAX	(~0U)
+#define LONG_MAX	((long)(~0UL >> 1))
+#define LONG_MIN	(-LONG_MAX - 1)
+#define ULONG_MAX	(~0UL)
+#define LLONG_MAX	((long long)(~0ULL >> 1))
+#define LLONG_MIN	(-LLONG_MAX - 1)
+#define ULLONG_MAX	(~0ULL)
+#define UINTPTR_MAX	ULONG_MAX
+
+#endif /* __VDSO_LIMITS_H */

include/vdso/math64.h

@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_MATH64_H
+#define __VDSO_MATH64_H
+
+static __always_inline u32
+__iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
+{
+	u32 ret = 0;
+
+	while (dividend >= divisor) {
+		/* The following asm() prevents the compiler from
+		   optimising this loop into a modulo operation.  */
+		asm("" : "+rm"(dividend));
+
+		dividend -= divisor;
+		ret++;
+	}
+
+	*remainder = dividend;
+
+	return ret;
+}
+
+#endif /* __VDSO_MATH64_H */

include/vdso/processor.h

@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 ARM Ltd.
+ */
+#ifndef __VDSO_PROCESSOR_H
+#define __VDSO_PROCESSOR_H
+
+#ifndef __ASSEMBLY__
+
+#include <asm/vdso/processor.h>
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __VDSO_PROCESSOR_H */

include/vdso/time.h

@@ -0,0 +1,5 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_TIME_H
+#define __VDSO_TIME_H
+
+#endif /* __VDSO_TIME_H */

include/vdso/time32.h

@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_TIME32_H
+#define __VDSO_TIME32_H
+
+/*
+ * New aliases for compat time functions. These will be used to replace
+ * the compat code so it can be shared between 32-bit and 64-bit builds
+ * both of which provide compatibility with old 32-bit tasks.
+ */
+#define old_time32_t		compat_time_t
+#define old_timeval32		compat_timeval
+#define old_timespec32		compat_timespec
+
+#endif /* __VDSO_TIME32_H */

include/vdso/time64.h

@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_TIME64_H
+#define __VDSO_TIME64_H
+
+/* Parameters used to convert the timespec values: */
+#define MSEC_PER_SEC	1000L
+#define USEC_PER_MSEC	1000L
+#define NSEC_PER_USEC	1000L
+#define NSEC_PER_MSEC	1000000L
+#define USEC_PER_SEC	1000000L
+#define NSEC_PER_SEC	1000000000L
+#define FSEC_PER_SEC	1000000000000000LL
+
+#endif /* __VDSO_TIME64_H */

include/vdso/vsyscall.h

@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_VSYSCALL_H
+#define __VDSO_VSYSCALL_H
+
+#ifndef __ASSEMBLY__
+
+#include <asm/vdso/vsyscall.h>
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __VDSO_VSYSCALL_H */