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authorLinus Torvalds <torvalds@linux-foundation.org>2019-07-08 11:06:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-08 11:06:29 -0700
commit927ba67a63c72ee87d655e30183d1576c3717d3e (patch)
tree85f941aeac5581ef6b612c5b5949f2e2896103c5 /lib
parent2a1ccd31420a7b1acd6ca37b2bec2d723aa093e4 (diff)
parent9176ab1b848059a0cd9caf39f0cebaa1b7ec5ec2 (diff)
Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner: "The timer and timekeeping departement delivers: Core: - The consolidation of the VDSO code into a generic library including the conversion of x86 and ARM64. Conversion of ARM and MIPS are en route through the relevant maintainer trees and should end up in 5.4. This gets rid of the unnecessary different copies of the same code and brings all architectures on the same level of VDSO functionality. - Make the NTP user space interface more robust by restricting the TAI offset to prevent undefined behaviour. Includes a selftest. - Validate user input in the compat settimeofday() syscall to catch invalid values which would be turned into valid values by a multiplication overflow - Consolidate the time accessors - Small fixes, improvements and cleanups all over the place Drivers: - Support for the NXP system counter, TI davinci timer - Move the Microsoft HyperV clocksource/events code into the drivers/clocksource directory so it can be shared between x86 and ARM64. - Overhaul of the Tegra driver - Delay timer support for IXP4xx - Small fixes, improvements and cleanups as usual" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (71 commits) time: Validate user input in compat_settimeofday() timer: Document TIMER_PINNED clocksource/drivers: Continue making Hyper-V clocksource ISA agnostic clocksource/drivers: Make Hyper-V clocksource ISA agnostic MAINTAINERS: Fix Andy's surname and the directory entries of VDSO hrtimer: Use a bullet for the returns bullet list arm64: vdso: Fix compilation with clang older than 8 arm64: compat: Fix __arch_get_hw_counter() implementation arm64: Fix __arch_get_hw_counter() implementation lib/vdso: Make delta calculation work correctly MAINTAINERS: Add entry for the generic VDSO library arm64: compat: No need for pre-ARMv7 barriers on an ARMv8 system arm64: vdso: Remove unnecessary asm-offsets.c definitions vdso: Remove superfluous #ifdef __KERNEL__ in vdso/datapage.h clocksource/drivers/davinci: Add support for clocksource clocksource/drivers/davinci: Add support for clockevents clocksource/drivers/tegra: Set up maximum-ticks limit properly clocksource/drivers/tegra: Cycles can't be 0 clocksource/drivers/tegra: Restore base address before cleanup clocksource/drivers/tegra: Add verbose definition for 1MHz constant ...
Diffstat (limited to 'lib')
-rw-r--r--lib/Kconfig5
-rw-r--r--lib/vdso/Kconfig36
-rw-r--r--lib/vdso/Makefile22
-rw-r--r--lib/vdso/gettimeofday.c239
4 files changed, 302 insertions, 0 deletions
diff --git a/lib/Kconfig b/lib/Kconfig
index 90623a0e1942..8c8eefc5e54c 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -576,6 +576,11 @@ config OID_REGISTRY
config UCS2_STRING
tristate
+#
+# generic vdso
+#
+source "lib/vdso/Kconfig"
+
source "lib/fonts/Kconfig"
config SG_SPLIT
diff --git a/lib/vdso/Kconfig b/lib/vdso/Kconfig
new file mode 100644
index 000000000000..cc00364bd2c2
--- /dev/null
+++ b/lib/vdso/Kconfig
@@ -0,0 +1,36 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config HAVE_GENERIC_VDSO
+ bool
+
+if HAVE_GENERIC_VDSO
+
+config GENERIC_GETTIMEOFDAY
+ bool
+ help
+ This is a generic implementation of gettimeofday vdso.
+ Each architecture that enables this feature has to
+ provide the fallback implementation.
+
+config GENERIC_VDSO_32
+ bool
+ depends on GENERIC_GETTIMEOFDAY && !64BIT
+ help
+ This config option helps to avoid possible performance issues
+ in 32 bit only architectures.
+
+config GENERIC_COMPAT_VDSO
+ bool
+ help
+ This config option enables the compat VDSO layer.
+
+config CROSS_COMPILE_COMPAT_VDSO
+ string "32 bit Toolchain prefix for compat vDSO"
+ default ""
+ depends on GENERIC_COMPAT_VDSO
+ help
+ Defines the cross-compiler prefix for compiling compat vDSO.
+ If a 64 bit compiler (i.e. x86_64) can compile the VDSO for
+ 32 bit, it does not need to define this parameter.
+
+endif
diff --git a/lib/vdso/Makefile b/lib/vdso/Makefile
new file mode 100644
index 000000000000..c415a685d61b
--- /dev/null
+++ b/lib/vdso/Makefile
@@ -0,0 +1,22 @@
+# SPDX-License-Identifier: GPL-2.0
+
+GENERIC_VDSO_MK_PATH := $(abspath $(lastword $(MAKEFILE_LIST)))
+GENERIC_VDSO_DIR := $(dir $(GENERIC_VDSO_MK_PATH))
+
+c-gettimeofday-$(CONFIG_GENERIC_GETTIMEOFDAY) := $(addprefix $(GENERIC_VDSO_DIR), gettimeofday.c)
+
+# This cmd checks that the vdso library does not contain absolute relocation
+# It has to be called after the linking of the vdso library and requires it
+# as a parameter.
+#
+# $(ARCH_REL_TYPE_ABS) is defined in the arch specific makefile and corresponds
+# to the absolute relocation types printed by "objdump -R" and accepted by the
+# dynamic linker.
+ifndef ARCH_REL_TYPE_ABS
+$(error ARCH_REL_TYPE_ABS is not set)
+endif
+
+quiet_cmd_vdso_check = VDSOCHK $@
+ cmd_vdso_check = if $(OBJDUMP) -R $@ | egrep -h "$(ARCH_REL_TYPE_ABS)"; \
+ then (echo >&2 "$@: dynamic relocations are not supported"; \
+ rm -f $@; /bin/false); fi
diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c
new file mode 100644
index 000000000000..2d1c1f241fd9
--- /dev/null
+++ b/lib/vdso/gettimeofday.c
@@ -0,0 +1,239 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic userspace implementations of gettimeofday() and similar.
+ */
+#include <linux/compiler.h>
+#include <linux/math64.h>
+#include <linux/time.h>
+#include <linux/kernel.h>
+#include <linux/hrtimer_defs.h>
+#include <vdso/datapage.h>
+#include <vdso/helpers.h>
+
+/*
+ * The generic vDSO implementation requires that gettimeofday.h
+ * provides:
+ * - __arch_get_vdso_data(): to get the vdso datapage.
+ * - __arch_get_hw_counter(): to get the hw counter based on the
+ * clock_mode.
+ * - gettimeofday_fallback(): fallback for gettimeofday.
+ * - clock_gettime_fallback(): fallback for clock_gettime.
+ * - clock_getres_fallback(): fallback for clock_getres.
+ */
+#ifdef ENABLE_COMPAT_VDSO
+#include <asm/vdso/compat_gettimeofday.h>
+#else
+#include <asm/vdso/gettimeofday.h>
+#endif /* ENABLE_COMPAT_VDSO */
+
+#ifndef vdso_calc_delta
+/*
+ * Default implementation which works for all sane clocksources. That
+ * obviously excludes x86/TSC.
+ */
+static __always_inline
+u64 vdso_calc_delta(u64 cycles, u64 last, u64 mask, u32 mult)
+{
+ return ((cycles - last) & mask) * mult;
+}
+#endif
+
+static int do_hres(const struct vdso_data *vd, clockid_t clk,
+ struct __kernel_timespec *ts)
+{
+ const struct vdso_timestamp *vdso_ts = &vd->basetime[clk];
+ u64 cycles, last, sec, ns;
+ u32 seq;
+
+ do {
+ seq = vdso_read_begin(vd);
+ cycles = __arch_get_hw_counter(vd->clock_mode);
+ ns = vdso_ts->nsec;
+ last = vd->cycle_last;
+ if (unlikely((s64)cycles < 0))
+ return clock_gettime_fallback(clk, ts);
+
+ ns += vdso_calc_delta(cycles, last, vd->mask, vd->mult);
+ ns >>= vd->shift;
+ sec = vdso_ts->sec;
+ } while (unlikely(vdso_read_retry(vd, seq)));
+
+ /*
+ * Do this outside the loop: a race inside the loop could result
+ * in __iter_div_u64_rem() being extremely slow.
+ */
+ ts->tv_sec = sec + __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+ ts->tv_nsec = ns;
+
+ return 0;
+}
+
+static void do_coarse(const struct vdso_data *vd, clockid_t clk,
+ struct __kernel_timespec *ts)
+{
+ const struct vdso_timestamp *vdso_ts = &vd->basetime[clk];
+ u32 seq;
+
+ do {
+ seq = vdso_read_begin(vd);
+ ts->tv_sec = vdso_ts->sec;
+ ts->tv_nsec = vdso_ts->nsec;
+ } while (unlikely(vdso_read_retry(vd, seq)));
+}
+
+static __maybe_unused int
+__cvdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts)
+{
+ const struct vdso_data *vd = __arch_get_vdso_data();
+ u32 msk;
+
+ /* Check for negative values or invalid clocks */
+ if (unlikely((u32) clock >= MAX_CLOCKS))
+ goto fallback;
+
+ /*
+ * Convert the clockid to a bitmask and use it to check which
+ * clocks are handled in the VDSO directly.
+ */
+ msk = 1U << clock;
+ if (likely(msk & VDSO_HRES)) {
+ return do_hres(&vd[CS_HRES_COARSE], clock, ts);
+ } else if (msk & VDSO_COARSE) {
+ do_coarse(&vd[CS_HRES_COARSE], clock, ts);
+ return 0;
+ } else if (msk & VDSO_RAW) {
+ return do_hres(&vd[CS_RAW], clock, ts);
+ }
+
+fallback:
+ return clock_gettime_fallback(clock, ts);
+}
+
+static __maybe_unused int
+__cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res)
+{
+ struct __kernel_timespec ts;
+ int ret;
+
+ if (res == NULL)
+ goto fallback;
+
+ ret = __cvdso_clock_gettime(clock, &ts);
+
+ if (ret == 0) {
+ res->tv_sec = ts.tv_sec;
+ res->tv_nsec = ts.tv_nsec;
+ }
+
+ return ret;
+
+fallback:
+ return clock_gettime_fallback(clock, (struct __kernel_timespec *)res);
+}
+
+static __maybe_unused int
+__cvdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
+{
+ const struct vdso_data *vd = __arch_get_vdso_data();
+
+ if (likely(tv != NULL)) {
+ struct __kernel_timespec ts;
+
+ if (do_hres(&vd[CS_HRES_COARSE], CLOCK_REALTIME, &ts))
+ return gettimeofday_fallback(tv, tz);
+
+ tv->tv_sec = ts.tv_sec;
+ tv->tv_usec = (u32)ts.tv_nsec / NSEC_PER_USEC;
+ }
+
+ if (unlikely(tz != NULL)) {
+ tz->tz_minuteswest = vd[CS_HRES_COARSE].tz_minuteswest;
+ tz->tz_dsttime = vd[CS_HRES_COARSE].tz_dsttime;
+ }
+
+ return 0;
+}
+
+#ifdef VDSO_HAS_TIME
+static __maybe_unused time_t __cvdso_time(time_t *time)
+{
+ const struct vdso_data *vd = __arch_get_vdso_data();
+ time_t t = READ_ONCE(vd[CS_HRES_COARSE].basetime[CLOCK_REALTIME].sec);
+
+ if (time)
+ *time = t;
+
+ return t;
+}
+#endif /* VDSO_HAS_TIME */
+
+#ifdef VDSO_HAS_CLOCK_GETRES
+static __maybe_unused
+int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *res)
+{
+ const struct vdso_data *vd = __arch_get_vdso_data();
+ u64 ns;
+ u32 msk;
+ u64 hrtimer_res = READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res);
+
+ /* Check for negative values or invalid clocks */
+ if (unlikely((u32) clock >= MAX_CLOCKS))
+ goto fallback;
+
+ /*
+ * Convert the clockid to a bitmask and use it to check which
+ * clocks are handled in the VDSO directly.
+ */
+ msk = 1U << clock;
+ if (msk & VDSO_HRES) {
+ /*
+ * Preserves the behaviour of posix_get_hrtimer_res().
+ */
+ ns = hrtimer_res;
+ } else if (msk & VDSO_COARSE) {
+ /*
+ * Preserves the behaviour of posix_get_coarse_res().
+ */
+ ns = LOW_RES_NSEC;
+ } else if (msk & VDSO_RAW) {
+ /*
+ * Preserves the behaviour of posix_get_hrtimer_res().
+ */
+ ns = hrtimer_res;
+ } else {
+ goto fallback;
+ }
+
+ if (res) {
+ res->tv_sec = 0;
+ res->tv_nsec = ns;
+ }
+
+ return 0;
+
+fallback:
+ return clock_getres_fallback(clock, res);
+}
+
+static __maybe_unused int
+__cvdso_clock_getres_time32(clockid_t clock, struct old_timespec32 *res)
+{
+ struct __kernel_timespec ts;
+ int ret;
+
+ if (res == NULL)
+ goto fallback;
+
+ ret = __cvdso_clock_getres(clock, &ts);
+
+ if (ret == 0) {
+ res->tv_sec = ts.tv_sec;
+ res->tv_nsec = ts.tv_nsec;
+ }
+
+ return ret;
+
+fallback:
+ return clock_getres_fallback(clock, (struct __kernel_timespec *)res);
+}
+#endif /* VDSO_HAS_CLOCK_GETRES */