bionic: Optimizations for gettimeofday and clock_gettime.
Use the kernel user helper feature to calculate the results
of gettimeofday and clock_gettime without actually calling
into kernel space. If the user helper patches have not been
applied to the kernel, the regular system calls are used as
a fallback.
Change-Id: I3aebc6ac19ab4743725648a1a279819e624cc5c4
diff --git a/libc/Android.mk b/libc/Android.mk
index 8a11e24..370af72 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -408,6 +408,18 @@
endif # !TARGET_USE_KRAIT_BIONIC_OPTIMIZATION
endif # !TARGET_USE_SCORPION_BIONIC_OPTIMIZATION
+# If the kernel supports kernel user helpers for gettimeofday, use
+# that instead.
+ifeq ($(KERNEL_HAS_GETTIMEOFDAY_HELPER),true)
+ libc_common_src_files := $(filter-out arch-arm/syscalls/gettimeofday.S,$(libc_common_src_files))
+ libc_common_src_files := $(filter-out arch-arm/syscalls/clock_gettime.S,$(libc_common_src_files))
+ libc_common_src_files += \
+ arch-arm/bionic/gettimeofday.c \
+ arch-arm/bionic/gettimeofday_syscall.S \
+ arch-arm/bionic/clock_gettime.c \
+ arch-arm/bionic/clock_gettime_syscall.S
+endif # KERNEL_HAS_GETTIMEOFDAY_HELPER
+
# These files need to be arm so that gdbserver
# can set breakpoints in them without messing
# up any thumb code.
diff --git a/libc/arch-arm/bionic/clock_gettime.c b/libc/arch-arm/bionic/clock_gettime.c
new file mode 100644
index 0000000..c2917b0
--- /dev/null
+++ b/libc/arch-arm/bionic/clock_gettime.c
@@ -0,0 +1,94 @@
+/* Copyright (c) 2012, The Linux Foundation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials provided
+ * with the distribution.
+ * * Neither the name of The Linux Foundation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+ * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <string.h>
+#include <stdint.h>
+#include <time.h>
+#include <sys/time.h>
+#include <machine/cpu-features.h>
+#include <machine/kernel_user_helper.h>
+
+int clock_gettime(int clk_id, struct timespec *tp)
+{
+ unsigned prelock, postlock;
+
+ /*
+ * Check if the offset in the kernel user helper page has
+ * the flag set appropriately to show that this feature is
+ * enabled in the kernel. If not, default to the original
+ * clock_gettime system call.
+ *
+ * Also, if this is anything other than CLOCK_MONOTONIC, route
+ * to the original system call as well.
+ */
+ if ((__kuser_gtod_feature != __kuser_gtod_feature_flag) ||
+ (clk_id != CLOCK_MONOTONIC))
+ return clock_gettime_syscall(clk_id, tp);
+
+ if (tp) {
+ struct gtod_t dgtod;
+ uint32_t nscount, cycleoffset;
+ uint32_t mono_sec, mono_nsec;
+ uint64_t cycle_delta;
+
+ do {
+ prelock = __kuser_gtod_seqnum;
+
+ dgtod.cycle_last = __kuser_gtod_cycle_last;
+ dgtod.mask = __kuser_gtod_mask;
+ dgtod.mult = __kuser_gtod_mult;
+ dgtod.shift = __kuser_gtod_shift;
+ dgtod.tv_sec = __kuser_gtod_tv_sec;
+ dgtod.tv_nsec = __kuser_gtod_tv_nsec;
+
+ mono_sec = __kuser_gtod_wtm_tv_sec;
+ mono_nsec = __kuser_gtod_wtm_tv_nsec;
+
+ cycleoffset = __kuser_gtod_offset;
+ cycleoffset += __kuser_gtod_cycle_base;
+ nscount = *(uint32_t *)cycleoffset;
+
+ postlock = __kuser_gtod_seqnum;
+ } while (prelock != postlock);
+
+ cycle_delta = (nscount - dgtod.cycle_last) & dgtod.mask;
+ dgtod.tv_nsec += (cycle_delta * dgtod.mult) >> dgtod.shift;
+ dgtod.tv_sec += mono_sec;
+ dgtod.tv_nsec += mono_nsec;
+ while (dgtod.tv_nsec >= NSEC_PER_SEC) {
+ dgtod.tv_sec += 1;
+ dgtod.tv_nsec -= NSEC_PER_SEC;
+ }
+
+ tp->tv_sec = dgtod.tv_sec;
+ tp->tv_nsec = dgtod.tv_nsec;
+ }
+
+ return 0;
+}
diff --git a/libc/arch-arm/bionic/clock_gettime_syscall.S b/libc/arch-arm/bionic/clock_gettime_syscall.S
new file mode 100644
index 0000000..0b3078a
--- /dev/null
+++ b/libc/arch-arm/bionic/clock_gettime_syscall.S
@@ -0,0 +1,42 @@
+/* Copyright (c) 2012, The Linux Foundation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials provided
+ * with the distribution.
+ * * Neither the name of The Linux Foundation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+ * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <machine/asm.h>
+#include <sys/linux-syscalls.h>
+
+ENTRY(clock_gettime_syscall)
+ .save {r4, r7}
+ stmfd sp!, {r4, r7}
+ ldr r7, =__NR_clock_gettime
+ swi #0
+ movs r0, r0
+ ldmfd sp!, {r4, r7}
+ bmi __set_syscall_errno
+ bx lr
+END(clock_gettime_syscall)
diff --git a/libc/arch-arm/bionic/gettimeofday.c b/libc/arch-arm/bionic/gettimeofday.c
new file mode 100644
index 0000000..780d6e8
--- /dev/null
+++ b/libc/arch-arm/bionic/gettimeofday.c
@@ -0,0 +1,99 @@
+/* Copyright (c) 2012, The Linux Foundation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials provided
+ * with the distribution.
+ * * Neither the name of The Linux Foundation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+ * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <string.h>
+#include <stdint.h>
+#include <sys/time.h>
+#include <machine/cpu-features.h>
+#include <machine/kernel_user_helper.h>
+
+int gettimeofday(struct timeval *tv, struct timezone *tz)
+{
+ unsigned prelock, postlock;
+
+ /*
+ * Check if the offset in the kernel user helper page has
+ * the flag set appropriately to show that this feature is
+ * enabled in the kernel. If not, default to the original
+ * gettimeofday system call.
+ */
+ if (__kuser_gtod_feature != __kuser_gtod_feature_flag)
+ return gettimeofday_syscall(tv, tz);
+
+ if (tv) {
+ struct gtod_t dgtod;
+ uint32_t nscount, cycleoffset;
+ uint64_t cycle_delta;
+ uint32_t tmp = 0;
+
+ do {
+ prelock = __kuser_gtod_seqnum;
+
+ dgtod.cycle_last = __kuser_gtod_cycle_last;
+ dgtod.mask = __kuser_gtod_mask;
+ dgtod.mult = __kuser_gtod_mult;
+ dgtod.shift = __kuser_gtod_shift;
+ dgtod.tv_sec = __kuser_gtod_tv_sec;
+ dgtod.tv_nsec = __kuser_gtod_tv_nsec;
+
+ cycleoffset = __kuser_gtod_offset;
+ cycleoffset += __kuser_gtod_cycle_base;
+ nscount = *(uint32_t *)cycleoffset;
+
+ postlock = __kuser_gtod_seqnum;
+ } while (prelock != postlock);
+
+ cycle_delta = (nscount - dgtod.cycle_last) & dgtod.mask;
+ dgtod.tv_nsec += (cycle_delta * dgtod.mult) >> dgtod.shift;
+ while (dgtod.tv_nsec >= NSEC_PER_SEC) {
+ dgtod.tv_sec += 1;
+ dgtod.tv_nsec -= NSEC_PER_SEC;
+ }
+
+ tv->tv_sec = dgtod.tv_sec;
+ asm(" movw %[tmp], #0x4dd3\n\t"
+ " movt %[tmp], #0x1062\n\t"
+ " umull %[tmp], %[x], %[y], %[tmp]\n\t"
+ " lsr %[x], %[x], #6\n\t" :
+ [x] "=r" (tv->tv_usec) :
+ [y] "r" (dgtod.tv_nsec), [tmp] "r" (tmp)
+ : );
+ }
+
+ if (tz) {
+ do {
+ prelock = __kuser_gtod_seqnum;
+ tz->tz_minuteswest = __kuser_gtod_tz_minw;
+ tz->tz_dsttime = __kuser_gtod_tz_dst;
+ postlock = __kuser_gtod_seqnum;
+ } while (prelock != postlock);
+ }
+
+ return 0;
+}
diff --git a/libc/arch-arm/bionic/gettimeofday_syscall.S b/libc/arch-arm/bionic/gettimeofday_syscall.S
new file mode 100644
index 0000000..3a945e2
--- /dev/null
+++ b/libc/arch-arm/bionic/gettimeofday_syscall.S
@@ -0,0 +1,42 @@
+/* Copyright (c) 2012, The Linux Foundation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials provided
+ * with the distribution.
+ * * Neither the name of The Linux Foundation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+ * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <machine/asm.h>
+#include <sys/linux-syscalls.h>
+
+ENTRY(gettimeofday_syscall)
+ .save {r4, r7}
+ stmfd sp!, {r4, r7}
+ ldr r7, =__NR_gettimeofday
+ swi #0
+ movs r0, r0
+ ldmfd sp!, {r4, r7}
+ bmi __set_syscall_errno
+ bx lr
+END(gettimeofday_syscall)
diff --git a/libc/arch-arm/include/machine/kernel_user_helper.h b/libc/arch-arm/include/machine/kernel_user_helper.h
new file mode 100644
index 0000000..8836c50
--- /dev/null
+++ b/libc/arch-arm/include/machine/kernel_user_helper.h
@@ -0,0 +1,68 @@
+/* Copyright (c) 2012, The Linux Foundation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials provided
+ * with the distribution.
+ * * Neither the name of The Linux Foundation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+ * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef _ARCH_ARM_KERNEL_USER_HELPER_H
+#define _ARCH_ARM_KERNEL_USER_HELPER_H
+
+extern int clock_gettime_syscall(int clk_id, struct timespec *tp);
+extern int gettimeofday_syscall(struct timeval *tv, struct timezone *tz);
+
+#define __kuser_gtod_base (*(int32_t *)0xffff0f40)
+#define __kuser_gtod_cycle_last (*(int32_t *)0xffff0f40)
+#define __kuser_gtod_mask (*(int32_t *)0xffff0f48)
+#define __kuser_gtod_mult (*(int32_t *)0xffff0f50)
+#define __kuser_gtod_shift (*(int32_t *)0xffff0f54)
+#define __kuser_gtod_tv_sec (*(int32_t *)0xffff0f58)
+#define __kuser_gtod_tv_nsec (*(int32_t *)0xffff0f5c)
+
+#define __kuser_gtod_seqnum (*(int32_t *)0xffff0f28)
+#define __kuser_gtod_offset (*(int32_t *)0xffff0f30)
+#define __kuser_gtod_cycle_base 0xfffef000
+#define __kuser_gtod_feature (*(int32_t *)0xffff0f34)
+#define __kuser_gtod_feature_flag 0xffff0f20
+
+#define __kuser_gtod_wtm_tv_sec (*(int32_t *)0xffff0f38)
+#define __kuser_gtod_wtm_tv_nsec (*(int32_t *)0xffff0f3c)
+
+#define __kuser_gtod_timezone (*(int32_t *)0xffff0f20)
+#define __kuser_gtod_tz_minw (*(int32_t *)0xffff0f20)
+#define __kuser_gtod_tz_dst (*(int32_t *)0xffff0f24)
+
+struct gtod_t {
+ uint64_t cycle_last;
+ uint64_t mask;
+ uint32_t mult;
+ uint32_t shift;
+ uint32_t tv_sec;
+ uint32_t tv_nsec;
+};
+
+#define NSEC_PER_SEC 1000000000L
+
+#endif