ARM: 8930/1: Add support for generic vDSO

The arm vDSO library requires some adaptations to take advantage of
the newly introduced generic vDSO library.

Introduce the following changes:
 - Modification vdso.c to be compliant with the common vdso datapage
 - Use of lib/vdso for gettimeofday
 - Implementation of elf note

Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

3 files changed, 148 insertions, 26 deletions

diff --git a/arch/arm/include/asm/vdso/gettimeofday.h b/arch/arm/include/asm/vdso/gettimeofday.h
new file mode 100644
index 000000000000..30ce4e87dffc
--- /dev/null
+++ b/arch/arm/include/asm/vdso/gettimeofday.h
@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2018 ARM Limited
+ */
+#ifndef __ASM_VDSO_GETTIMEOFDAY_H
+#define __ASM_VDSO_GETTIMEOFDAY_H
+
+#ifndef __ASSEMBLY__
+
+#include <asm/barrier.h>
+#include <asm/cp15.h>
+#include <asm/unistd.h>
+#include <uapi/linux/time.h>
+
+extern struct vdso_data *__get_datapage(void);
+
+static __always_inline int gettimeofday_fallback(
+				struct __kernel_old_timeval *_tv,
+				struct timezone *_tz)
+{
+	register struct timezone *tz asm("r1") = _tz;
+	register struct __kernel_old_timeval *tv asm("r0") = _tv;
+	register long ret asm ("r0");
+	register long nr asm("r7") = __NR_gettimeofday;
+
+	asm volatile(
+	"	swi #0\n"
+	: "=r" (ret)
+	: "r" (tv), "r" (tz), "r" (nr)
+	: "memory");
+
+	return ret;
+}
+
+static __always_inline long clock_gettime_fallback(
+					clockid_t _clkid,
+					struct __kernel_timespec *_ts)
+{
+	register struct __kernel_timespec *ts asm("r1") = _ts;
+	register clockid_t clkid asm("r0") = _clkid;
+	register long ret asm ("r0");
+	register long nr asm("r7") = __NR_clock_gettime64;
+
+	asm volatile(
+	"	swi #0\n"
+	: "=r" (ret)
+	: "r" (clkid), "r" (ts), "r" (nr)
+	: "memory");
+
+	return ret;
+}
+
+static __always_inline u64 __arch_get_hw_counter(int clock_mode)
+{
+#ifdef CONFIG_ARM_ARCH_TIMER
+	u64 cycle_now;
+
+	isb();
+	cycle_now = read_sysreg(CNTVCT);
+
+	return cycle_now;
+#else
+	return -EINVAL; /* use fallback */
+#endif
+}
+
+static __always_inline const struct vdso_data *__arch_get_vdso_data(void)
+{
+	return __get_datapage();
+}
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_GETTIMEOFDAY_H */
diff --git a/arch/arm/include/asm/vdso/vsyscall.h b/arch/arm/include/asm/vdso/vsyscall.h
new file mode 100644
index 000000000000..c4166f317071
--- /dev/null
+++ b/arch/arm/include/asm/vdso/vsyscall.h
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_VDSO_VSYSCALL_H
+#define __ASM_VDSO_VSYSCALL_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/timekeeper_internal.h>
+#include <vdso/datapage.h>
+#include <asm/cacheflush.h>
+
+extern struct vdso_data *vdso_data;
+extern bool cntvct_ok;
+
+static __always_inline
+bool tk_is_cntvct(const struct timekeeper *tk)
+{
+	if (!IS_ENABLED(CONFIG_ARM_ARCH_TIMER))
+		return false;
+
+	if (!tk->tkr_mono.clock->archdata.vdso_direct)
+		return false;
+
+	return true;
+}
+
+/*
+ * Update the vDSO data page to keep in sync with kernel timekeeping.
+ */
+static __always_inline
+struct vdso_data *__arm_get_k_vdso_data(void)
+{
+	return vdso_data;
+}
+#define __arch_get_k_vdso_data __arm_get_k_vdso_data
+
+static __always_inline
+int __arm_update_vdso_data(void)
+{
+	return !cntvct_ok;
+}
+#define __arch_update_vdso_data __arm_update_vdso_data
+
+static __always_inline
+int __arm_get_clock_mode(struct timekeeper *tk)
+{
+	u32 __tk_is_cntvct = tk_is_cntvct(tk);
+
+	return __tk_is_cntvct;
+}
+#define __arch_get_clock_mode __arm_get_clock_mode
+
+static __always_inline
+int __arm_use_vsyscall(struct vdso_data *vdata)
+{
+	return vdata[CS_HRES_COARSE].clock_mode;
+}
+#define __arch_use_vsyscall __arm_use_vsyscall
+
+static __always_inline
+void __arm_sync_vdso_data(struct vdso_data *vdata)
+{
+	flush_dcache_page(virt_to_page(vdata));
+}
+#define __arch_sync_vdso_data __arm_sync_vdso_data
+
+/* The asm-generic header needs to be included after the definitions above */
+#include <asm-generic/vdso/vsyscall.h>
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_VSYSCALL_H */
diff --git a/arch/arm/include/asm/vdso_datapage.h b/arch/arm/include/asm/vdso_datapage.h
index 7910abf89b1c..bef68f59928d 100644
--- a/arch/arm/include/asm/vdso_datapage.h
+++ b/arch/arm/include/asm/vdso_datapage.h
@@ -11,35 +11,12 @@
 
 #ifndef __ASSEMBLY__
 
+#include <vdso/datapage.h>
 #include <asm/page.h>
 
-/* Try to be cache-friendly on systems that don't implement the
- * generic timer: fit the unconditionally updated fields in the first
- * 32 bytes.
- */
-struct vdso_data {
-	u32 seq_count;		/* sequence count - odd during updates */
-	u16 tk_is_cntvct;	/* fall back to syscall if false */
-	u16 cs_shift;		/* clocksource shift */
-	u32 xtime_coarse_sec;	/* coarse time */
-	u32 xtime_coarse_nsec;
-
-	u32 wtm_clock_sec;	/* wall to monotonic offset */
-	u32 wtm_clock_nsec;
-	u32 xtime_clock_sec;	/* CLOCK_REALTIME - seconds */
-	u32 cs_mult;		/* clocksource multiplier */
-
-	u64 cs_cycle_last;	/* last cycle value */
-	u64 cs_mask;		/* clocksource mask */
-
-	u64 xtime_clock_snsec;	/* CLOCK_REALTIME sub-ns base */
-	u32 tz_minuteswest;	/* timezone info for gettimeofday(2) */
-	u32 tz_dsttime;
-};
-
 union vdso_data_store {
-	struct vdso_data data;
-	u8 page[PAGE_SIZE];
+	struct vdso_data	data[CS_BASES];
+	u8			page[PAGE_SIZE];
 };
 
 #endif /* !__ASSEMBLY__ */