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
...
This commit is contained in:
Linus Torvalds
@@ -576,6 +576,11 @@ config OID_REGISTRY
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config UCS2_STRING
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tristate
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#
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# generic vdso
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#
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source "lib/vdso/Kconfig"
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source "lib/fonts/Kconfig"
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config SG_SPLIT
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36
lib/vdso/Kconfig
Normal file
36
lib/vdso/Kconfig
Normal file
@@ -0,0 +1,36 @@
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# SPDX-License-Identifier: GPL-2.0
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config HAVE_GENERIC_VDSO
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bool
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if HAVE_GENERIC_VDSO
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config GENERIC_GETTIMEOFDAY
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bool
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help
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This is a generic implementation of gettimeofday vdso.
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Each architecture that enables this feature has to
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provide the fallback implementation.
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config GENERIC_VDSO_32
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bool
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depends on GENERIC_GETTIMEOFDAY && !64BIT
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help
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This config option helps to avoid possible performance issues
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in 32 bit only architectures.
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config GENERIC_COMPAT_VDSO
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bool
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help
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This config option enables the compat VDSO layer.
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config CROSS_COMPILE_COMPAT_VDSO
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string "32 bit Toolchain prefix for compat vDSO"
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default ""
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depends on GENERIC_COMPAT_VDSO
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help
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Defines the cross-compiler prefix for compiling compat vDSO.
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If a 64 bit compiler (i.e. x86_64) can compile the VDSO for
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32 bit, it does not need to define this parameter.
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endif
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22
lib/vdso/Makefile
Normal file
22
lib/vdso/Makefile
Normal file
@@ -0,0 +1,22 @@
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# SPDX-License-Identifier: GPL-2.0
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GENERIC_VDSO_MK_PATH := $(abspath $(lastword $(MAKEFILE_LIST)))
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GENERIC_VDSO_DIR := $(dir $(GENERIC_VDSO_MK_PATH))
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c-gettimeofday-$(CONFIG_GENERIC_GETTIMEOFDAY) := $(addprefix $(GENERIC_VDSO_DIR), gettimeofday.c)
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# This cmd checks that the vdso library does not contain absolute relocation
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# It has to be called after the linking of the vdso library and requires it
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# as a parameter.
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#
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# $(ARCH_REL_TYPE_ABS) is defined in the arch specific makefile and corresponds
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# to the absolute relocation types printed by "objdump -R" and accepted by the
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# dynamic linker.
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ifndef ARCH_REL_TYPE_ABS
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$(error ARCH_REL_TYPE_ABS is not set)
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endif
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quiet_cmd_vdso_check = VDSOCHK $@
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cmd_vdso_check = if $(OBJDUMP) -R $@ | egrep -h "$(ARCH_REL_TYPE_ABS)"; \
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then (echo >&2 "$@: dynamic relocations are not supported"; \
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rm -f $@; /bin/false); fi
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239
lib/vdso/gettimeofday.c
Normal file
239
lib/vdso/gettimeofday.c
Normal file
@@ -0,0 +1,239 @@
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Generic userspace implementations of gettimeofday() and similar.
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*/
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#include <linux/compiler.h>
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#include <linux/math64.h>
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#include <linux/time.h>
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#include <linux/kernel.h>
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#include <linux/hrtimer_defs.h>
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#include <vdso/datapage.h>
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#include <vdso/helpers.h>
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/*
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* The generic vDSO implementation requires that gettimeofday.h
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* provides:
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* - __arch_get_vdso_data(): to get the vdso datapage.
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* - __arch_get_hw_counter(): to get the hw counter based on the
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* clock_mode.
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* - gettimeofday_fallback(): fallback for gettimeofday.
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* - clock_gettime_fallback(): fallback for clock_gettime.
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* - clock_getres_fallback(): fallback for clock_getres.
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*/
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#ifdef ENABLE_COMPAT_VDSO
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#include <asm/vdso/compat_gettimeofday.h>
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#else
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#include <asm/vdso/gettimeofday.h>
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#endif /* ENABLE_COMPAT_VDSO */
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#ifndef vdso_calc_delta
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/*
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* Default implementation which works for all sane clocksources. That
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* obviously excludes x86/TSC.
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*/
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static __always_inline
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u64 vdso_calc_delta(u64 cycles, u64 last, u64 mask, u32 mult)
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{
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return ((cycles - last) & mask) * mult;
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}
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#endif
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static int do_hres(const struct vdso_data *vd, clockid_t clk,
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struct __kernel_timespec *ts)
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{
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const struct vdso_timestamp *vdso_ts = &vd->basetime[clk];
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u64 cycles, last, sec, ns;
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u32 seq;
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do {
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seq = vdso_read_begin(vd);
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cycles = __arch_get_hw_counter(vd->clock_mode);
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ns = vdso_ts->nsec;
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last = vd->cycle_last;
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if (unlikely((s64)cycles < 0))
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return clock_gettime_fallback(clk, ts);
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ns += vdso_calc_delta(cycles, last, vd->mask, vd->mult);
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ns >>= vd->shift;
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sec = vdso_ts->sec;
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} while (unlikely(vdso_read_retry(vd, seq)));
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/*
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* Do this outside the loop: a race inside the loop could result
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* in __iter_div_u64_rem() being extremely slow.
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*/
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ts->tv_sec = sec + __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
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ts->tv_nsec = ns;
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return 0;
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}
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static void do_coarse(const struct vdso_data *vd, clockid_t clk,
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struct __kernel_timespec *ts)
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{
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const struct vdso_timestamp *vdso_ts = &vd->basetime[clk];
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u32 seq;
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do {
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seq = vdso_read_begin(vd);
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ts->tv_sec = vdso_ts->sec;
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ts->tv_nsec = vdso_ts->nsec;
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} while (unlikely(vdso_read_retry(vd, seq)));
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}
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static __maybe_unused int
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__cvdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts)
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{
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const struct vdso_data *vd = __arch_get_vdso_data();
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u32 msk;
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/* Check for negative values or invalid clocks */
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if (unlikely((u32) clock >= MAX_CLOCKS))
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goto fallback;
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/*
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* Convert the clockid to a bitmask and use it to check which
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* clocks are handled in the VDSO directly.
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*/
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msk = 1U << clock;
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if (likely(msk & VDSO_HRES)) {
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return do_hres(&vd[CS_HRES_COARSE], clock, ts);
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} else if (msk & VDSO_COARSE) {
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do_coarse(&vd[CS_HRES_COARSE], clock, ts);
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return 0;
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} else if (msk & VDSO_RAW) {
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return do_hres(&vd[CS_RAW], clock, ts);
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}
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fallback:
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return clock_gettime_fallback(clock, ts);
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}
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static __maybe_unused int
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__cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res)
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{
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struct __kernel_timespec ts;
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int ret;
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if (res == NULL)
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goto fallback;
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ret = __cvdso_clock_gettime(clock, &ts);
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if (ret == 0) {
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res->tv_sec = ts.tv_sec;
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res->tv_nsec = ts.tv_nsec;
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}
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return ret;
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fallback:
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return clock_gettime_fallback(clock, (struct __kernel_timespec *)res);
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}
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static __maybe_unused int
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__cvdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
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{
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const struct vdso_data *vd = __arch_get_vdso_data();
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if (likely(tv != NULL)) {
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struct __kernel_timespec ts;
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if (do_hres(&vd[CS_HRES_COARSE], CLOCK_REALTIME, &ts))
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return gettimeofday_fallback(tv, tz);
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tv->tv_sec = ts.tv_sec;
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tv->tv_usec = (u32)ts.tv_nsec / NSEC_PER_USEC;
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}
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if (unlikely(tz != NULL)) {
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tz->tz_minuteswest = vd[CS_HRES_COARSE].tz_minuteswest;
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tz->tz_dsttime = vd[CS_HRES_COARSE].tz_dsttime;
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}
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return 0;
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}
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#ifdef VDSO_HAS_TIME
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static __maybe_unused time_t __cvdso_time(time_t *time)
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{
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const struct vdso_data *vd = __arch_get_vdso_data();
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time_t t = READ_ONCE(vd[CS_HRES_COARSE].basetime[CLOCK_REALTIME].sec);
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if (time)
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*time = t;
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return t;
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}
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#endif /* VDSO_HAS_TIME */
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#ifdef VDSO_HAS_CLOCK_GETRES
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static __maybe_unused
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int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *res)
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{
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const struct vdso_data *vd = __arch_get_vdso_data();
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u64 ns;
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u32 msk;
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u64 hrtimer_res = READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res);
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/* Check for negative values or invalid clocks */
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if (unlikely((u32) clock >= MAX_CLOCKS))
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goto fallback;
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/*
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* Convert the clockid to a bitmask and use it to check which
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* clocks are handled in the VDSO directly.
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*/
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msk = 1U << clock;
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if (msk & VDSO_HRES) {
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/*
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* Preserves the behaviour of posix_get_hrtimer_res().
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*/
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ns = hrtimer_res;
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} else if (msk & VDSO_COARSE) {
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/*
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* Preserves the behaviour of posix_get_coarse_res().
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*/
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ns = LOW_RES_NSEC;
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} else if (msk & VDSO_RAW) {
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/*
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* Preserves the behaviour of posix_get_hrtimer_res().
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*/
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ns = hrtimer_res;
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} else {
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goto fallback;
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}
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if (res) {
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res->tv_sec = 0;
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res->tv_nsec = ns;
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}
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return 0;
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fallback:
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return clock_getres_fallback(clock, res);
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}
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static __maybe_unused int
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__cvdso_clock_getres_time32(clockid_t clock, struct old_timespec32 *res)
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{
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struct __kernel_timespec ts;
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int ret;
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if (res == NULL)
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goto fallback;
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ret = __cvdso_clock_getres(clock, &ts);
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if (ret == 0) {
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res->tv_sec = ts.tv_sec;
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res->tv_nsec = ts.tv_nsec;
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}
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return ret;
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fallback:
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return clock_getres_fallback(clock, (struct __kernel_timespec *)res);
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}
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#endif /* VDSO_HAS_CLOCK_GETRES */
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Reference in New Issue
Block a user