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kernel-49/kernel/trace/trace_clock.c
Greg Kroah-Hartman 8ec09e737b Merge 4.9.274 into android-4.9-q
Changes in 4.9.274
	net: ieee802154: fix null deref in parse dev addr
	HID: hid-sensor-hub: Return error for hid_set_field() failure
	HID: Add BUS_VIRTUAL to hid_connect logging
	HID: usbhid: fix info leak in hid_submit_ctrl
	ARM: OMAP2+: Fix build warning when mmc_omap is not built
	HID: gt683r: add missing MODULE_DEVICE_TABLE
	gfs2: Fix use-after-free in gfs2_glock_shrink_scan
	scsi: target: core: Fix warning on realtime kernels
	ethernet: myri10ge: Fix missing error code in myri10ge_probe()
	net: ipconfig: Don't override command-line hostnames or domains
	rtnetlink: Fix missing error code in rtnl_bridge_notify()
	net/x25: Return the correct errno code
	net: Return the correct errno code
	fib: Return the correct errno code
	dmaengine: QCOM_HIDMA_MGMT depends on HAS_IOMEM
	dmaengine: stedma40: add missing iounmap() on error in d40_probe()
	mm: hwpoison: change PageHWPoison behavior on hugetlb pages
	batman-adv: Avoid WARN_ON timing related checks
	net: ipv4: fix memory leak in netlbl_cipsov4_add_std
	net: rds: fix memory leak in rds_recvmsg
	udp: fix race between close() and udp_abort()
	rtnetlink: Fix regression in bridge VLAN configuration
	netfilter: synproxy: Fix out of bounds when parsing TCP options
	alx: Fix an error handling path in 'alx_probe()'
	net: stmmac: dwmac1000: Fix extended MAC address registers definition
	qlcnic: Fix an error handling path in 'qlcnic_probe()'
	netxen_nic: Fix an error handling path in 'netxen_nic_probe()'
	net: cdc_ncm: switch to eth%d interface naming
	net: usb: fix possible use-after-free in smsc75xx_bind
	net: ipv4: fix memory leak in ip_mc_add1_src
	net/af_unix: fix a data-race in unix_dgram_sendmsg / unix_release_sock
	be2net: Fix an error handling path in 'be_probe()'
	net: hamradio: fix memory leak in mkiss_close
	net: cdc_eem: fix tx fixup skb leak
	net: ethernet: fix potential use-after-free in ec_bhf_remove
	scsi: core: Put .shost_dev in failure path if host state changes to RUNNING
	radeon: use memcpy_to/fromio for UVD fw upload
	can: bcm: fix infoleak in struct bcm_msg_head
	tracing: Do no increment trace_clock_global() by one
	PCI: Mark TI C667X to avoid bus reset
	PCI: Mark some NVIDIA GPUs to avoid bus reset
	dmaengine: pl330: fix wrong usage of spinlock flags in dma_cyclc
	net: fec_ptp: add clock rate zero check
	can: bcm/raw/isotp: use per module netdevice notifier
	usb: dwc3: core: fix kernel panic when do reboot
	tracing: Do not stop recording cmdlines when tracing is off
	tracing: Do not stop recording comms if the trace file is being read
	x86/fpu: Reset state for all signal restore failures
	inet: use bigger hash table for IP ID generation
	i40e: Be much more verbose about what we can and cannot offload
	ARM: 9081/1: fix gcc-10 thumb2-kernel regression
	Makefile: Move -Wno-unused-but-set-variable out of GCC only block
	arm64: perf: Disable PMU while processing counter overflows
	Revert "PCI: PM: Do not read power state in pci_enable_device_flags()"
	mac80211: remove warning in ieee80211_get_sband()
	cfg80211: call cfg80211_leave_ocb when switching away from OCB
	mac80211: drop multicast fragments
	ping: Check return value of function 'ping_queue_rcv_skb'
	inet: annotate date races around sk->sk_txhash
	net: caif: fix memory leak in ldisc_open
	net/packet: annotate accesses to po->bind
	net/packet: annotate accesses to po->ifindex
	r8152: Avoid memcpy() over-reading of ETH_SS_STATS
	sh_eth: Avoid memcpy() over-reading of ETH_SS_STATS
	r8169: Avoid memcpy() over-reading of ETH_SS_STATS
	net: qed: Fix memcpy() overflow of qed_dcbx_params()
	net: ll_temac: Avoid ndo_start_xmit returning NETDEV_TX_BUSY
	nilfs2: fix memory leak in nilfs_sysfs_delete_device_group
	i2c: robotfuzz-osif: fix control-request directions
	Linux 4.9.274

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I31d1bfc426326657ecc9db939474f25961471552
2021-07-02 12:35:13 +03:00

157 lines
4.1 KiB
C

/*
* tracing clocks
*
* Copyright (C) 2009 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
*
* Implements 3 trace clock variants, with differing scalability/precision
* tradeoffs:
*
* - local: CPU-local trace clock
* - medium: scalable global clock with some jitter
* - global: globally monotonic, serialized clock
*
* Tracer plugins will chose a default from these clocks.
*/
#include <linux/spinlock.h>
#include <linux/irqflags.h>
#include <linux/hardirq.h>
#include <linux/module.h>
#include <linux/percpu.h>
#include <linux/sched.h>
#include <linux/ktime.h>
#include <linux/trace_clock.h>
/*
* trace_clock_local(): the simplest and least coherent tracing clock.
*
* Useful for tracing that does not cross to other CPUs nor
* does it go through idle events.
*/
u64 notrace trace_clock_local(void)
{
u64 clock;
/*
* sched_clock() is an architecture implemented, fast, scalable,
* lockless clock. It is not guaranteed to be coherent across
* CPUs, nor across CPU idle events.
*/
preempt_disable_notrace();
clock = sched_clock();
preempt_enable_notrace();
return clock;
}
EXPORT_SYMBOL_GPL(trace_clock_local);
/*
* trace_clock(): 'between' trace clock. Not completely serialized,
* but not completely incorrect when crossing CPUs either.
*
* This is based on cpu_clock(), which will allow at most ~1 jiffy of
* jitter between CPUs. So it's a pretty scalable clock, but there
* can be offsets in the trace data.
*/
u64 notrace trace_clock(void)
{
return local_clock();
}
EXPORT_SYMBOL_GPL(trace_clock);
/*
* trace_jiffy_clock(): Simply use jiffies as a clock counter.
* Note that this use of jiffies_64 is not completely safe on
* 32-bit systems. But the window is tiny, and the effect if
* we are affected is that we will have an obviously bogus
* timestamp on a trace event - i.e. not life threatening.
*/
u64 notrace trace_clock_jiffies(void)
{
return jiffies_64_to_clock_t(jiffies_64 - INITIAL_JIFFIES);
}
EXPORT_SYMBOL_GPL(trace_clock_jiffies);
/*
* trace_clock_global(): special globally coherent trace clock
*
* It has higher overhead than the other trace clocks but is still
* an order of magnitude faster than GTOD derived hardware clocks.
*
* Used by plugins that need globally coherent timestamps.
*/
/* keep prev_time and lock in the same cacheline. */
static struct {
u64 prev_time;
arch_spinlock_t lock;
} trace_clock_struct ____cacheline_aligned_in_smp =
{
.lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED,
};
u64 notrace trace_clock_global(void)
{
unsigned long flags;
int this_cpu;
u64 now, prev_time;
local_irq_save(flags);
this_cpu = raw_smp_processor_id();
/*
* The global clock "guarantees" that the events are ordered
* between CPUs. But if two events on two different CPUS call
* trace_clock_global at roughly the same time, it really does
* not matter which one gets the earlier time. Just make sure
* that the same CPU will always show a monotonic clock.
*
* Use a read memory barrier to get the latest written
* time that was recorded.
*/
smp_rmb();
prev_time = READ_ONCE(trace_clock_struct.prev_time);
now = sched_clock_cpu(this_cpu);
/* Make sure that now is always greater than or equal to prev_time */
if ((s64)(now - prev_time) < 0)
now = prev_time;
/*
* If in an NMI context then dont risk lockups and simply return
* the current time.
*/
if (unlikely(in_nmi()))
goto out;
/* Tracing can cause strange recursion, always use a try lock */
if (arch_spin_trylock(&trace_clock_struct.lock)) {
/* Reread prev_time in case it was already updated */
prev_time = READ_ONCE(trace_clock_struct.prev_time);
if ((s64)(now - prev_time) < 0)
now = prev_time;
trace_clock_struct.prev_time = now;
/* The unlock acts as the wmb for the above rmb */
arch_spin_unlock(&trace_clock_struct.lock);
}
out:
local_irq_restore(flags);
return now;
}
EXPORT_SYMBOL_GPL(trace_clock_global);
static atomic64_t trace_counter;
/*
* trace_clock_counter(): simply an atomic counter.
* Use the trace_counter "counter" for cases where you do not care
* about timings, but are interested in strict ordering.
*/
u64 notrace trace_clock_counter(void)
{
return atomic64_add_return(1, &trace_counter);
}