[PATCH v3 03/12] arm: vdso: inline assembler operations to compiler.h
Mark Salyzyn
salyzyn at android.com
Fri Oct 27 15:25:10 PDT 2017
Move compiler-specific code to a local compiler.h file. CONFIG_AEABI
dependency check. System call fallback functions standardized into
a DEFINE_FALLBACK macro. Accept that __arch_counter_get_cntvct()
is the API for aarch64. Deal with unresolved references emitted by
GCC. Optimize handling of fallback calls. Most notably add unlikely
nullptr checking to __vdso_gettimeofday, if tv null no need to
proceed to fallback, as vdso is capable of filling in the tv values.
For time functions that always return success, do not waste time
checking return value for switch to fallback.
Signed-off-by: Mark Salyzyn <salyzyn at android.com>
Cc: James Morse <james.morse at arm.com>
Cc: Russell King <linux at armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Will Deacon <will.deacon at arm.com>
Cc: Andy Lutomirski <luto at amacapital.net>
Cc: Dmitry Safonov <dsafonov at virtuozzo.com>
Cc: John Stultz <john.stultz at linaro.org>
Cc: Mark Rutland <mark.rutland at arm.com>
Cc: Laura Abbott <labbott at redhat.com>
Cc: Kees Cook <keescook at chromium.org>
Cc: Ard Biesheuvel <ard.biesheuvel at linaro.org>
Cc: Andy Gross <andy.gross at linaro.org>
Cc: Kevin Brodsky <kevin.brodsky at arm.com>
Cc: Andrew Pinski <apinski at cavium.com>
Cc: linux-kernel at vger.kernel.org
Cc: linux-arm-kernel at lists.infradead.org
v2:
- split first CL into 3 of 7 pieces
v3:
- rebase (unchanged)
---
arch/arm/vdso/compiler.h | 69 ++++++++++++++++++++++++++
arch/arm/vdso/vgettimeofday.c | 109 +++++++++++-------------------------------
2 files changed, 96 insertions(+), 82 deletions(-)
create mode 100644 arch/arm/vdso/compiler.h
diff --git a/arch/arm/vdso/compiler.h b/arch/arm/vdso/compiler.h
new file mode 100644
index 000000000000..ef1d664fb4fa
--- /dev/null
+++ b/arch/arm/vdso/compiler.h
@@ -0,0 +1,69 @@
+/*
+ * Userspace implementations of fallback calls
+ *
+ * Copyright (C) 2017 Cavium, Inc.
+ * Copyright (C) 2012 ARM Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Will Deacon <will.deacon at arm.com>
+ * Rewriten into C by: Andrew Pinski <apinski at cavium.com>
+ */
+
+#ifndef __VDSO_COMPILER_H
+#define __VDSO_COMPILER_H
+
+#include <asm/arch_timer.h>
+#include <asm/processor.h>
+#include <asm/unistd.h>
+#include <linux/compiler.h>
+
+#ifndef CONFIG_AEABI
+#error This code depends on AEABI system call conventions
+#endif
+
+#define DEFINE_FALLBACK(name, type_arg1, name_arg1, type_arg2, name_arg2) \
+static notrace long name##_fallback(type_arg1 _##name_arg1, \
+ type_arg2 _##name_arg2) \
+{ \
+ register type_arg1 name_arg1 asm("r0") = _##name_arg1; \
+ register type_arg2 name_arg2 asm("r1") = _##name_arg2; \
+ register long ret asm ("r0"); \
+ register long nr asm("r7") = __NR_##name; \
+ \
+ asm volatile( \
+ " swi #0\n" \
+ : "=r" (ret) \
+ : "r" (name_arg1), "r" (name_arg2), "r" (nr) \
+ : "memory"); \
+ \
+ return ret; \
+}
+
+#define __arch_counter_get_cntvct() arch_counter_get_cntvct()
+
+/* Avoid unresolved references emitted by GCC */
+
+void __aeabi_unwind_cpp_pr0(void)
+{
+}
+
+void __aeabi_unwind_cpp_pr1(void)
+{
+}
+
+void __aeabi_unwind_cpp_pr2(void)
+{
+}
+
+#endif /* __VDSO_COMPILER_H */
diff --git a/arch/arm/vdso/vgettimeofday.c b/arch/arm/vdso/vgettimeofday.c
index 2474c17dc356..5f596911bd53 100644
--- a/arch/arm/vdso/vgettimeofday.c
+++ b/arch/arm/vdso/vgettimeofday.c
@@ -22,21 +22,16 @@
* Reworked and rebased over arm version by: Mark Salyzyn <salyzyn at android.com>
*/
-#include <linux/compiler.h>
-#include <linux/hrtimer.h>
-#include <linux/time.h>
-#include <asm/arch_timer.h>
#include <asm/barrier.h>
-#include <asm/bug.h>
-#include <asm/page.h>
-#include <asm/unistd.h>
-
-#ifndef CONFIG_AEABI
-#error This code depends on AEABI system call conventions
-#endif
+#include <linux/time.h>
+#include <linux/hrtimer.h>
+#include "compiler.h"
#include "datapage.h"
+DEFINE_FALLBACK(gettimeofday, struct timeval *, tv, struct timezone *, tz)
+DEFINE_FALLBACK(clock_gettime, clockid_t, clock, struct timespec *, ts)
+
static notrace u32 vdso_read_begin(const struct vdso_data *vd)
{
u32 seq;
@@ -63,23 +58,6 @@ static notrace int vdso_read_retry(const struct vdso_data *vd, u32 start)
return seq != start;
}
-static notrace long clock_gettime_fallback(clockid_t _clkid,
- struct timespec *_ts)
-{
- register struct timespec *ts asm("r1") = _ts;
- register clockid_t clkid asm("r0") = _clkid;
- register long ret asm ("r0");
- register long nr asm("r7") = __NR_clock_gettime;
-
- asm volatile(
- " swi #0\n"
- : "=r" (ret)
- : "r" (clkid), "r" (ts), "r" (nr)
- : "memory");
-
- return ret;
-}
-
static notrace int do_realtime_coarse(const struct vdso_data *vd,
struct timespec *ts)
{
@@ -127,7 +105,7 @@ static notrace u64 get_ns(const struct vdso_data *vd)
u64 cycle_now;
u64 nsec;
- cycle_now = arch_counter_get_cntvct();
+ cycle_now = __arch_counter_get_cntvct();
cycle_delta = (cycle_now - vd->cs_cycle_last) & vd->cs_mask;
@@ -200,85 +178,52 @@ static notrace int do_monotonic(const struct vdso_data *vd, struct timespec *ts)
#endif /* CONFIG_ARM_ARCH_TIMER */
-notrace int __vdso_clock_gettime(clockid_t clkid, struct timespec *ts)
+notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
{
- int ret = -1;
-
const struct vdso_data *vd = __get_datapage();
- switch (clkid) {
+ switch (clock) {
case CLOCK_REALTIME_COARSE:
- ret = do_realtime_coarse(vd, ts);
+ do_realtime_coarse(vd, ts);
break;
case CLOCK_MONOTONIC_COARSE:
- ret = do_monotonic_coarse(vd, ts);
+ do_monotonic_coarse(vd, ts);
break;
case CLOCK_REALTIME:
- ret = do_realtime(vd, ts);
+ if (do_realtime(vd, ts))
+ goto fallback;
break;
case CLOCK_MONOTONIC:
- ret = do_monotonic(vd, ts);
+ if (do_monotonic(vd, ts))
+ goto fallback;
break;
default:
- break;
+ goto fallback;
}
- if (ret)
- ret = clock_gettime_fallback(clkid, ts);
-
- return ret;
-}
-
-static notrace long gettimeofday_fallback(struct timeval *_tv,
- struct timezone *_tz)
-{
- register struct timezone *tz asm("r1") = _tz;
- register struct 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;
+ return 0;
+fallback:
+ return clock_gettime_fallback(clock, ts);
}
notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
{
- struct timespec ts;
- int ret;
-
const struct vdso_data *vd = __get_datapage();
- ret = do_realtime(vd, &ts);
- if (ret)
- return gettimeofday_fallback(tv, tz);
+ if (likely(tv != NULL)) {
+ struct timespec ts;
+
+ if (do_realtime(vd, &ts))
+ return gettimeofday_fallback(tv, tz);
- if (tv) {
tv->tv_sec = ts.tv_sec;
tv->tv_usec = ts.tv_nsec / 1000;
}
- if (tz) {
+
+ if (unlikely(tz != NULL)) {
tz->tz_minuteswest = vd->tz_minuteswest;
tz->tz_dsttime = vd->tz_dsttime;
}
- return ret;
-}
-
-/* Avoid unresolved references emitted by GCC */
-
-void __aeabi_unwind_cpp_pr0(void)
-{
-}
-
-void __aeabi_unwind_cpp_pr1(void)
-{
-}
-
-void __aeabi_unwind_cpp_pr2(void)
-{
+ return 0;
}
--
2.15.0.rc2.357.g7e34df9404-goog
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