Jason A. Donenfeld 8cea35e3a0 timekeeping: Add raw clock fallback for random_get_entropy() ... commit 1366992e16bddd5e2d9a561687f367f9f802e2e4 upstream. The addition of random_get_entropy_fallback() provides access to whichever time source has the highest frequency, which is useful for gathering entropy on platforms without available cycle counters. It's not necessarily as good as being able to quickly access a cycle counter that the CPU has, but it's still something, even when it falls back to being jiffies-based. In the event that a given arch does not define get_cycles(), falling back to the get_cycles() default implementation that returns 0 is really not the best we can do. Instead, at least calling random_get_entropy_fallback() would be preferable, because that always needs to return _something_, even falling back to jiffies eventually. It's not as though random_get_entropy_fallback() is super high precision or guaranteed to be entropic, but basically anything that's not zero all the time is better than returning zero all the time. Finally, since random_get_entropy_fallback() is used during extremely early boot when randomizing freelists in mm_init(), it can be called before timekeeping has been initialized. In that case there really is nothing we can do; jiffies hasn't even started ticking yet. So just give up and return 0. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2022-06-25 11:49:10 +02:00
..
bpf	bpf: Add kconfig knob for disabling unpriv bpf by default	2022-02-16 12:51:45 +01:00
cgroup	cgroup/cpuset: Remove cpus_allowed/mems_allowed setup in cpuset_init_smp()	2022-05-18 09:42:49 +02:00
configs
debug	kdb: Make memory allocations more robust	2021-03-04 09:39:31 +01:00
dma	dma-debug: change allocation mode from GFP_NOWAIT to GFP_ATIOMIC	2022-06-14 16:59:16 +02:00
events	perf: Fix sys_perf_event_open() race against self	2022-05-25 09:10:38 +02:00
gcov	gcov: add support for GCC 10.1	2020-09-17 13:45:31 +02:00
irq	random: remove unused irq_flags argument from add_interrupt_randomness()	2022-06-25 11:49:01 +02:00
livepatch	livepatch: Nullify obj->mod in klp_module_coming()'s error path	2019-10-07 18:57:10 +02:00
locking	locking/lockdep: Avoid RCU-induced noinstr fail	2021-11-26 11:36:04 +01:00
power	PM: suspend: fix return value of __setup handler	2022-04-15 14:14:43 +02:00
printk	printk: fix return value of printk.devkmsg __setup handler	2022-04-15 14:14:45 +02:00
rcu	rcu: Fix missed wakeup of exp_wq waiters	2021-09-26 13:39:46 +02:00
sched	sched/debug: Remove mpol_get/put and task_lock/unlock from sched_show_numa	2022-04-15 14:14:44 +02:00
time	timekeeping: Add raw clock fallback for random_get_entropy()	2022-06-25 11:49:10 +02:00
trace	tracing: Avoid adding tracer option before update_tracer_options	2022-06-14 16:59:34 +02:00
.gitignore
acct.c	acct_on(): don't mess with freeze protection	2019-05-31 06:46:05 -07:00
async.c	Revert "module, async: async_synchronize_full() on module init iff async is used"	2022-02-23 11:58:38 +01:00
audit.c	audit: improve audit queue handling when "audit=1" on cmdline	2022-02-08 18:23:13 +01:00
audit.h	audit: fix a net reference leak in audit_list_rules_send()	2020-06-22 09:05:13 +02:00
audit_fsnotify.c
audit_tree.c	audit: Embed key into chunk	2019-12-13 08:51:11 +01:00
audit_watch.c	audit: CONFIG_CHANGE don't log internal bookkeeping as an event	2020-10-01 13:14:33 +02:00
auditfilter.c	audit: fix a net reference leak in audit_list_rules_send()	2020-06-22 09:05:13 +02:00
auditsc.c	audit: print empty EXECVE args	2019-12-01 09:17:17 +01:00
backtracetest.c
bounds.c
capability.c	LSM: generalize flag passing to security_capable	2020-01-23 08:21:29 +01:00
compat.c	make 'user_access_begin()' do 'access_ok()'	2020-06-22 09:04:58 +02:00
configs.c
context_tracking.c
cpu.c	random: clear fast pool, crng, and batches in cpuhp bring up	2022-06-25 11:49:07 +02:00
cpu_pm.c	kernel/cpu_pm: Fix uninitted local in cpu_pm	2020-06-22 09:05:28 +02:00
crash_core.c
crash_dump.c
cred.c	memcg: account security cred as well to kmemcg	2020-01-09 10:19:00 +01:00
delayacct.c
dma.c
exec_domain.c
exit.c	futex: Mark the begin of futex exit explicitly	2021-01-30 13:32:11 +01:00
extable.c
fail_function.c	fail_function: Remove a redundant mutex unlock	2020-11-24 13:27:23 +01:00
fork.c	mm/hugetlb: initialize hugetlb_usage in mm_init	2021-09-22 11:48:09 +02:00
freezer.c
futex.c	mm, futex: fix shared futex pgoff on shmem huge page	2021-07-11 12:49:30 +02:00
groups.c
hung_task.c	kernel: hung_task.c: disable on suspend	2019-04-20 09:16:02 +02:00
iomem.c
irq_work.c	irq_work: Do not raise an IPI when queueing work on the local CPU	2019-05-31 06:46:19 -07:00
jump_label.c	locking/static_key: Fix false positive warnings on concurrent dec/inc	2021-03-04 09:39:30 +01:00
kallsyms.c	kallsyms: Refactor kallsyms_show_value() to take cred	2020-07-16 08:17:26 +02:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c
kexec.c
kexec_core.c	kernel: kexec: remove the lock operation of system_transition_mutex	2021-02-03 23:23:23 +01:00
kexec_file.c	kernel: kexec_file: fix error return code of kexec_calculate_store_digests()	2021-05-22 10:59:44 +02:00
kexec_internal.h
kmod.c	kmod: make request_module() return an error when autoloading is disabled	2020-04-17 10:48:52 +02:00
kprobes.c	kprobes: Limit max data_size of the kretprobe instances	2021-12-08 08:50:12 +01:00
ksysfs.c
kthread.c	kthread: prevent deadlock when kthread_mod_delayed_work() races with kthread_cancel_delayed_work_sync()	2021-07-11 12:49:31 +02:00
latencytop.c
Makefile	elfcore: fix building with clang	2021-02-10 09:21:06 +01:00
memremap.c	mm/memory_hotplug: shrink zones when offlining memory	2020-01-29 16:43:27 +01:00
module-internal.h
module.c	Revert "module, async: async_synchronize_full() on module init iff async is used"	2022-02-23 11:58:38 +01:00
module_signing.c
notifier.c	x86/mm: split vmalloc_sync_all()	2020-03-25 08:06:13 +01:00
nsproxy.c
padata.c	padata: add separate cpuhp node for CPUHP_PADATA_DEAD	2021-08-08 08:54:30 +02:00
panic.c	kernel/panic.c: do not append newline to the stack protector panic string	2019-12-01 09:17:10 +01:00
params.c
pid.c
pid_namespace.c	memcg: enable accounting for pids in nested pid namespaces	2021-09-22 11:48:09 +02:00
profile.c	profiling: fix shift-out-of-bounds bugs	2021-09-26 13:39:48 +02:00
ptrace.c	ptrace: Reimplement PTRACE_KILL by always sending SIGKILL	2022-06-14 16:59:14 +02:00
range.c
reboot.c	reboot: fix overflow parsing reboot cpu number	2020-11-18 19:18:52 +01:00
relay.c	kernel/relay.c: fix memleak on destroy relay channel	2020-08-26 10:30:59 +02:00
resource.c	resource: fix locking in find_next_iomem_res()	2019-09-16 08:22:20 +02:00
rseq.c
seccomp.c	seccomp: Invalidate seccomp mode to catch death failures	2022-02-16 12:51:47 +01:00
signal.c	signal: Remove the bogus sigkill_pending in ptrace_stop	2021-11-26 11:36:02 +01:00
smp.c	smp: Fix offline cpu check in flush_smp_call_function_queue()	2022-04-20 09:12:50 +02:00
smpboot.c	kthread: Extract KTHREAD_IS_PER_CPU	2021-02-07 14:48:38 +01:00
smpboot.h
softirq.c
stacktrace.c
stop_machine.c
sys.c	prctl: allow to setup brk for et_dyn executables	2021-09-26 13:39:47 +02:00
sys_ni.c
sysctl.c	x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation reporting	2022-03-11 10:15:11 +01:00
sysctl_binary.c
task_work.c
taskstats.c	taskstats: fix data-race	2020-01-09 10:18:59 +01:00
test_kprobes.c
torture.c
tracepoint.c	tracepoint: Add tracepoint_probe_register_may_exist() for BPF tracing	2021-07-20 16:15:42 +02:00
tsacct.c	taskstats: Cleanup the use of task->exit_code	2022-02-23 11:58:39 +01:00
ucount.c
uid16.c
uid16.h
umh.c	usermodehelper: reset umask to default before executing user process	2020-10-14 10:31:21 +02:00
up.c	smp: Fix smp_call_function_single_async prototype	2021-05-22 10:59:39 +02:00
user-return-notifier.c
user.c
user_namespace.c
utsname.c
utsname_sysctl.c
watchdog.c	watchdog/softlockup: Enforce that timestamp is valid on boot	2020-02-24 08:34:49 +01:00
watchdog_hld.c
workqueue.c	workqueue: make sysfs of unbound kworker cpumask more clever	2021-11-26 11:36:06 +01:00
workqueue_internal.h