[PATCH v2]: arch: arm64: vdso: export the symbols for time()

From: Mark Salyzyn
Date: Mon Jun 15 2020 - 10:38:53 EST


From: Chiawei Wang <chiaweiwang@xxxxxxxxxx>

__cvdso_time() can be found in vDSO implementation,
but the symbols for time() are not exported.

Export the symbols and run bionic-benchmarks.

BEFORE:
bionic-benchmarks32 --bionic_extra BM_time_time
-----------------------------------------------------
Benchmark Time CPU Iterations
-----------------------------------------------------
BM_time_time 83.6 ns 83.5 ns 8385964

bionic-benchmarks64 --bionic_extra BM_time_time
-----------------------------------------------------
Benchmark Time CPU Iterations
-----------------------------------------------------
BM_time_time 63.5 ns 63.4 ns 11037509

AFTER:
bionic-benchmarks32 --bionic_extra BM_time_time
-----------------------------------------------------
Benchmark Time CPU Iterations
-----------------------------------------------------
BM_time_time 8.57 ns 8.56 ns 81887312

bionic-benchmarks64 --bionic_extra BM_time_time
-----------------------------------------------------
Benchmark Time CPU Iterations
-----------------------------------------------------
BM_time_time 7.52 ns 7.51 ns 93253809

Signed-off-by: Chiawei Wang <chiaweiwang@xxxxxxxxxx>
Signed-off-by: Mark Salyzyn <salyzyn@xxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: kernel-team@xxxxxxxxxxx
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: Enrico Weigelt <info@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Alexios Zavras <alexios.zavras@xxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
---
v2:
- add prototypes in both vgettimeofday.c
- use __kernel_old_time_t instead of time_t
---
arch/arm64/include/asm/vdso/compat_gettimeofday.h | 12 ++++++++++++
arch/arm64/include/asm/vdso/gettimeofday.h | 10 ++++++++++
arch/arm64/kernel/vdso/vdso.lds.S | 1 +
arch/arm64/kernel/vdso/vgettimeofday.c | 5 +++++
arch/arm64/kernel/vdso32/vdso.lds.S | 1 +
arch/arm64/kernel/vdso32/vgettimeofday.c | 5 +++++
6 files changed, 34 insertions(+)

diff --git a/arch/arm64/include/asm/vdso/compat_gettimeofday.h b/arch/arm64/include/asm/vdso/compat_gettimeofday.h
index b6907ae78e53..d0a5655785bd 100644
--- a/arch/arm64/include/asm/vdso/compat_gettimeofday.h
+++ b/arch/arm64/include/asm/vdso/compat_gettimeofday.h
@@ -14,8 +14,20 @@

#define VDSO_HAS_CLOCK_GETRES 1

+#define VDSO_HAS_TIME 1
+
#define BUILD_VDSO32 1

+extern int __vdso_clock_gettime(clockid_t clock,
+ struct old_timespec32 *ts);
+extern int __vdso_clock_gettime64(clockid_t clock,
+ struct __kernel_timespec *ts);
+extern int __vdso_gettimeofday(struct __kernel_old_timeval *tv,
+ struct timezone *tz);
+extern int __vdso_clock_getres(clockid_t clock_id,
+ struct old_timespec32 *res);
+extern __kernel_old_time_t time(__kernel_old_time_t *time);
+
static __always_inline
int gettimeofday_fallback(struct __kernel_old_timeval *_tv,
struct timezone *_tz)
diff --git a/arch/arm64/include/asm/vdso/gettimeofday.h b/arch/arm64/include/asm/vdso/gettimeofday.h
index afba6ba332f8..e0dcf0dce6c0 100644
--- a/arch/arm64/include/asm/vdso/gettimeofday.h
+++ b/arch/arm64/include/asm/vdso/gettimeofday.h
@@ -11,6 +11,16 @@

#define VDSO_HAS_CLOCK_GETRES 1

+#define VDSO_HAS_TIME 1
+
+extern int __kernel_clock_gettime(clockid_t clock,
+ struct __kernel_timespec *ts);
+extern int __kernel_gettimeofday(struct __kernel_old_timeval *tv,
+ struct timezone *tz);
+extern int __kernel_clock_getres(clockid_t clock_id,
+ struct __kernel_timespec *res);
+extern __kernel_old_time_t __vdso_time(__kernel_old_time_t *time);
+
static __always_inline
int gettimeofday_fallback(struct __kernel_old_timeval *_tv,
struct timezone *_tz)
diff --git a/arch/arm64/kernel/vdso/vdso.lds.S b/arch/arm64/kernel/vdso/vdso.lds.S
index 7ad2d3a0cd48..61dddb0af1a5 100644
--- a/arch/arm64/kernel/vdso/vdso.lds.S
+++ b/arch/arm64/kernel/vdso/vdso.lds.S
@@ -77,6 +77,7 @@ VERSION
__kernel_gettimeofday;
__kernel_clock_gettime;
__kernel_clock_getres;
+ __kernel_time;
local: *;
};
}
diff --git a/arch/arm64/kernel/vdso/vgettimeofday.c b/arch/arm64/kernel/vdso/vgettimeofday.c
index 4236cf34d7d9..9a9058ba1f89 100644
--- a/arch/arm64/kernel/vdso/vgettimeofday.c
+++ b/arch/arm64/kernel/vdso/vgettimeofday.c
@@ -23,3 +23,8 @@ int __kernel_clock_getres(clockid_t clock_id,
{
return __cvdso_clock_getres(clock_id, res);
}
+
+__kernel_old_time_t __vdso_time(__kernel_old_time_t *time)
+{
+ return __cvdso_time(time);
+}
diff --git a/arch/arm64/kernel/vdso32/vdso.lds.S b/arch/arm64/kernel/vdso32/vdso.lds.S
index a3944927eaeb..2222c78451b4 100644
--- a/arch/arm64/kernel/vdso32/vdso.lds.S
+++ b/arch/arm64/kernel/vdso32/vdso.lds.S
@@ -69,6 +69,7 @@ VERSION
__kernel_rt_sigreturn_arm;
__kernel_rt_sigreturn_thumb;
__vdso_clock_gettime64;
+ __vdso_time;
local: *;
};
}
diff --git a/arch/arm64/kernel/vdso32/vgettimeofday.c b/arch/arm64/kernel/vdso32/vgettimeofday.c
index 5acff29c5991..7eb988fa06d8 100644
--- a/arch/arm64/kernel/vdso32/vgettimeofday.c
+++ b/arch/arm64/kernel/vdso32/vgettimeofday.c
@@ -30,6 +30,11 @@ int __vdso_clock_getres(clockid_t clock_id,
return __cvdso_clock_getres_time32(clock_id, res);
}

+__kernel_old_time_t time(__kernel_old_time_t *time)
+{
+ return __cvdso_time(time);
+}
+
/* Avoid unresolved references emitted by GCC */

void __aeabi_unwind_cpp_pr0(void)
--
2.27.0.290.gba653c62da-goog