[PATCH v7 17/25] arm: Add clock_getres entry point

Vincenzo Frascino
2019-06-21T09:54:36Z

The generic vDSO library provides an implementation of clock_getres() that
can be leveraged by each architecture.

Add clock_getres() entry point on arm to be on pair with arm64.

Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
---
arch/arm/include/asm/vdso/gettimeofday.h | 20 ++++++++++++++++++++
arch/arm/vdso/vdso.lds.S | 1 +
arch/arm/vdso/vgettimeofday.c | 6 ++++++
3 files changed, 27 insertions(+)

diff --git a/arch/arm/include/asm/vdso/gettimeofday.h b/arch/arm/include/asm/vdso/gettimeofday.h
index 30ce4e87dffc..5b879ae7afc1 100644
--- a/arch/arm/include/asm/vdso/gettimeofday.h
+++ b/arch/arm/include/asm/vdso/gettimeofday.h
@@ -12,6 +12,8 @@
#include <asm/unistd.h>
#include <uapi/linux/time.h>

+#define VDSO_HAS_CLOCK_GETRES 1
+
extern struct vdso_data *__get_datapage(void);

static __always_inline int gettimeofday_fallback(
@@ -50,6 +52,24 @@ static __always_inline long clock_gettime_fallback(
return ret;
}

+static __always_inline int clock_getres_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_getres_time64;
+
+ 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
diff --git a/arch/arm/vdso/vdso.lds.S b/arch/arm/vdso/vdso.lds.S
index 89ca89f12d23..1d81e8c3acf6 100644
--- a/arch/arm/vdso/vdso.lds.S
+++ b/arch/arm/vdso/vdso.lds.S
@@ -82,6 +82,7 @@ VERSION
global:
__vdso_clock_gettime;
__vdso_gettimeofday;
+ __vdso_clock_getres;
local: *;
};
}
diff --git a/arch/arm/vdso/vgettimeofday.c b/arch/arm/vdso/vgettimeofday.c
index fea6b3c89f43..d3330c0c1147 100644
--- a/arch/arm/vdso/vgettimeofday.c
+++ b/arch/arm/vdso/vgettimeofday.c
@@ -32,6 +32,12 @@ int __vdso_gettimeofday(struct __kernel_old_timeval *tv,
return __cvdso_gettimeofday(tv, tz);
}

+int __vdso_clock_getres(clockid_t clock_id,
+ struct old_timespec32 *res)
+{
+ return __cvdso_clock_getres_time32(clock_id, res);
+}
+
/* Avoid unresolved references emitted by GCC */

void __aeabi_unwind_cpp_pr0(void)
--
2.21.0