Cheng Jian a124692b69 ftrace: Enable trampoline when rec count returns back to one ... Custom trampolines can only be enabled if there is only a single ops attached to it. If there's only a single callback registered to a function, and the ops has a trampoline registered for it, then we can call the trampoline directly. This is very useful for improving the performance of ftrace and livepatch. If more than one callback is registered to a function, the general trampoline is used, and the custom trampoline is not restored back to the direct call even if all the other callbacks were unregistered and we are back to one callback for the function. To fix this, set FTRACE_FL_TRAMP flag if rec count is decremented to one, and the ops that left has a trampoline. Testing After this patch : insmod livepatch_unshare_files.ko cat /sys/kernel/debug/tracing/enabled_functions unshare_files (1) R I tramp: 0xffffffffc0000000(klp_ftrace_handler+0x0/0xa0) ->ftrace_ops_assist_func+0x0/0xf0 echo unshare_files > /sys/kernel/debug/tracing/set_ftrace_filter echo function > /sys/kernel/debug/tracing/current_tracer cat /sys/kernel/debug/tracing/enabled_functions unshare_files (2) R I ->ftrace_ops_list_func+0x0/0x150 echo nop > /sys/kernel/debug/tracing/current_tracer cat /sys/kernel/debug/tracing/enabled_functions unshare_files (1) R I tramp: 0xffffffffc0000000(klp_ftrace_handler+0x0/0xa0) ->ftrace_ops_assist_func+0x0/0xf0 Link: http://lkml.kernel.org/r/1556969979-111047-1-git-send-email-cj.chengjian@huawei.com Signed-off-by: Cheng Jian <cj.chengjian@huawei.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>		2019-05-25 23:04:43 -04:00
..
bpf	bpf: fix undefined behavior in narrow load handling	2019-05-13 02:05:50 +02:00
cgroup	kernel/sched/psi.c: expose pressure metrics on root cgroup	2019-05-14 19:52:48 -07:00
configs
debug	kdb: Fix bound check compiler warning	2019-05-14 13:44:24 +01:00
dma	DMA mapping updates for 5.2	2019-05-09 08:40:55 -07:00
events	mm/mmu_notifier: use correct mmu_notifier events for each invalidation	2019-05-14 09:47:49 -07:00
gcov	gcov: clang support	2019-05-14 19:52:51 -07:00
irq	Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2019-05-19 10:58:45 -07:00
livepatch	The major changes in this tracing update includes:	2019-05-15 16:05:47 -07:00
locking	locking/rwsem: Prevent decrement of reader count before increment	2019-05-07 08:46:46 +02:00
power	Power management updates for 5.2-rc1	2019-05-06 19:40:31 -07:00
printk	panic: add an option to replay all the printk message in buffer	2019-05-18 15:52:26 -07:00
rcu	The major changes in this tracing update includes:	2019-05-15 16:05:47 -07:00
sched	kernel/sched/psi.c: expose pressure metrics on root cgroup	2019-05-14 19:52:48 -07:00
time	Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2019-05-16 11:00:20 -07:00
trace	ftrace: Enable trampoline when rec count returns back to one	2019-05-25 23:04:43 -04:00
.gitignore	Provide in-kernel headers to make extending kernel easier	2019-04-29 16:48:03 +02:00
acct.c	acct_on(): don't mess with freeze protection	2019-04-04 21:04:13 -04:00
async.c	treewide: Switch printk users from %pf and %pF to %ps and %pS, respectively	2019-04-09 14:19:06 +02:00
audit_fsnotify.c	audit_compare_dname_path(): switch to const struct qstr *	2019-04-28 20:33:43 -04:00
audit_tree.c	fsnotify: switch send_to_group() and ->handle_event to const struct qstr *	2019-04-26 13:51:03 -04:00
audit_watch.c	audit_compare_dname_path(): switch to const struct qstr *	2019-04-28 20:33:43 -04:00
audit.c	audit: connect LOGIN record to its syscall record	2019-03-20 20:57:48 -04:00
audit.h	audit_compare_dname_path(): switch to const struct qstr *	2019-04-28 20:33:43 -04:00
auditfilter.c	Merge branch 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2019-05-07 20:03:32 -07:00
auditsc.c	Merge branch 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2019-05-07 20:03:32 -07:00
backtracetest.c	backtrace-test: Simplify stack trace handling	2019-04-29 12:37:47 +02:00
bounds.c
capability.c	LSM: add SafeSetID module that gates setid calls	2019-01-25 11:22:43 -08:00
compat.c	kernel/compat.c: mark expected switch fall-throughs	2019-05-15 08:16:14 -07:00
configs.c	kernel/configs: use .incbin directive to embed config_data.gz	2019-03-07 18:32:02 -08:00
context_tracking.c
cpu_pm.c
cpu.c	Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2019-05-06 14:50:46 -07:00
crash_core.c	kexec: export PG_offline to VMCOREINFO	2019-03-05 21:07:14 -08:00
crash_dump.c
cred.c	SELinux: Remove cred security blob poisoning	2019-01-08 13:18:44 -08:00
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c	mm: change mm_update_next_owner() to update mm->owner with WRITE_ONCE	2019-05-14 19:52:47 -07:00
extable.c
fail_function.c	treewide: Switch printk users from %pf and %pF to %ps and %pS, respectively	2019-04-09 14:19:06 +02:00
fork.c	kernel/latencytop.c: rename clear_all_latency_tracing to clear_tsk_latency_tracing	2019-05-14 19:52:49 -07:00
freezer.c
futex.c	mm/gup: change GUP fast to use flags rather than a write 'bool'	2019-05-14 09:47:46 -07:00
gen_ikh_data.sh	Provide in-kernel headers to make extending kernel easier	2019-04-29 16:48:03 +02:00
groups.c
hung_task.c	kernel/hung_task.c: Use continuously blocked time when reporting.	2019-03-07 18:31:59 -08:00
iomem.c	mm/resource: Use resource_overlaps() to simplify region_intersects()	2019-04-19 12:59:36 +02:00
irq_work.c	irq_work: Do not raise an IPI when queueing work on the local CPU	2019-04-18 14:07:52 +02:00
jump_label.c	locking/static_key: Don't take sleeping locks in __static_key_slow_dec_deferred()	2019-04-29 08:29:21 +02:00
kallsyms.c	bpf: Add module name [bpf] to ksymbols for bpf programs	2019-01-21 17:38:56 -03:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks	Remove Mysterious Macro Intended to Obscure Weird Behaviours (mmiowb())	2019-05-06 16:57:52 -07:00
Kconfig.preempt	kconfig: warn no new line at end of file	2018-12-15 17:44:35 +09:00
kcov.c	kcov: convert kcov.refcount to refcount_t	2019-03-07 18:32:02 -08:00
kexec_core.c	power/suspend: Add function to disable secondaries for suspend	2019-05-03 19:42:41 +02:00
kexec_file.c	mm: memblock: make keeping memblock memory opt-in rather than opt-out	2019-05-14 09:47:50 -07:00
kexec_internal.h
kexec.c
kheaders.c	Provide in-kernel headers to make extending kernel easier	2019-04-29 16:48:03 +02:00
kmod.c
kprobes.c	kprobes: Initialize kprobes at postcore_initcall	2019-05-25 23:04:43 -04:00
ksysfs.c
kthread.c	include/: refactor headers to allow kthread.h inclusion in psi_types.h	2019-05-14 19:52:48 -07:00
latencytop.c	kernel/latencytop.c: rename clear_all_latency_tracing to clear_tsk_latency_tracing	2019-05-14 19:52:49 -07:00
Makefile	kernel/Makefile: don't assume that kernel/gen_ikh_data.sh is executable	2019-05-14 19:52:47 -07:00
memremap.c	kernel/memremap.c: remove the unused device_private_entry_fault() export	2019-05-14 09:47:51 -07:00
module_signing.c
module-internal.h	kallsyms: store type information in its own array	2019-03-28 15:00:37 +01:00
module.c	Modules updates for v5.2	2019-05-14 10:55:54 -07:00
notifier.c	kernel/notifier.c: double register detection	2019-05-14 19:52:49 -07:00
nsproxy.c
padata.c	padata: Replace padata_attr_type default_attrs field with groups	2019-04-25 22:06:11 +02:00
panic.c	panic: add an option to replay all the printk message in buffer	2019-05-18 15:52:26 -07:00
params.c
pid_namespace.c
pid.c	kernel/pid.c: remove unneeded hash header file	2019-05-14 19:52:51 -07:00
profile.c
ptrace.c	ptrace: take into account saved_sigmask in PTRACE{GET,SET}SIGMASK	2019-03-29 10:01:37 -07:00
range.c
reboot.c	panic/reboot: allow specifying reboot_mode for panic only	2019-05-14 19:52:51 -07:00
relay.c	Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2019-03-12 13:27:20 -07:00
resource.c	mm/resource: Use resource_overlaps() to simplify region_intersects()	2019-04-19 12:59:36 +02:00
rseq.c	rseq: Remove superfluous rseq_len from task_struct	2019-04-19 12:39:32 +02:00
seccomp.c	audit/stable-5.2 PR 20190507	2019-05-07 19:06:04 -07:00
signal.c	signal: unconditionally leave the frozen state in ptrace_stop()	2019-05-16 10:43:58 -07:00
smp.c	cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVM	2019-01-30 19:27:00 +01:00
smpboot.c
smpboot.h
softirq.c	softirq: Remove tasklet_hrtimer	2019-03-22 14:36:02 +01:00
stackleak.c
stacktrace.c	stacktrace: Provide common infrastructure	2019-04-29 12:37:57 +02:00
stop_machine.c	treewide: Switch printk users from %pf and %pF to %ps and %pS, respectively	2019-04-09 14:19:06 +02:00
sys_ni.c	signal: support CLONE_PIDFD with pidfd_send_signal	2019-05-07 14:31:03 +02:00
sys.c	kernel/sys.c: prctl: fix false positive in validate_prctl_map()	2019-05-14 09:47:44 -07:00
sysctl_binary.c	kernel/sysctl: add panic_print into sysctl	2019-01-04 13:13:47 -08:00
sysctl.c	kernel/sysctl.c: fix proc_do_large_bitmap for large input buffers	2019-05-14 19:52:51 -07:00
task_work.c
taskstats.c	genetlink: optionally validate strictly/dumps	2019-04-27 17:07:22 -04:00
test_kprobes.c
torture.c	torture: Don't try to offline the last CPU	2019-03-26 14:42:53 -07:00
tracepoint.c
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c	umh: add exit routine for UMH process	2019-01-11 18:05:40 -08:00
up.c
user_namespace.c
user-return-notifier.c
user.c	kernel/user.c: clean up some leftover code	2019-05-14 19:52:49 -07:00
utsname_sysctl.c
utsname.c
watchdog_hld.c	kernel/watchdog_hld.c: hard lockup message should end with a newline	2019-04-19 09:46:05 -07:00
watchdog.c	watchdog: Fix typo in comment	2019-04-18 14:05:51 +02:00
workqueue_internal.h	sched/core, workqueues: Distangle worker accounting from rq lock	2019-04-16 16:55:15 +02:00
workqueue.c	Merge branch 'for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq	2019-05-09 13:48:52 -07:00