Daniel Borkmann 8b614aebec bpf: move clearing of A/X into classic to eBPF migration prologue ... Back in the days where eBPF (or back then "internal BPF" ;->) was not exposed to user space, and only the classic BPF programs internally translated into eBPF programs, we missed the fact that for classic BPF A and X needed to be cleared. It was fixed back then via 83d5b7ef99 ("net: filter: initialize A and X registers"), and thus classic BPF specifics were added to the eBPF interpreter core to work around it. This added some confusion for JIT developers later on that take the eBPF interpreter code as an example for deriving their JIT. F.e. in f75298f5c3 ("s390/bpf: clear correct BPF accumulator register"), at least X could leak stack memory. Furthermore, since this is only needed for classic BPF translations and not for eBPF (verifier takes care that read access to regs cannot be done uninitialized), more complexity is added to JITs as they need to determine whether they deal with migrations or native eBPF where they can just omit clearing A/X in their prologue and thus reduce image size a bit, see f.e. cde66c2d88 ("s390/bpf: Only clear A and X for converted BPF programs"). In other cases (x86, arm64), A and X is being cleared in the prologue also for eBPF case, which is unnecessary. Lets move this into the BPF migration in bpf_convert_filter() where it actually belongs as long as the number of eBPF JITs are still few. It can thus be done generically; allowing us to remove the quirk from __bpf_prog_run() and to slightly reduce JIT image size in case of eBPF, while reducing code duplication on this matter in current(/future) eBPF JITs. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Tested-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Cc: Zi Shen Lim <zlim.lnx@gmail.com> Cc: Yang Shi <yang.shi@linaro.org> Acked-by: Yang Shi <yang.shi@linaro.org> Acked-by: Zi Shen Lim <zlim.lnx@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2015-12-18 16:04:51 -05:00
..
bpf	bpf: move clearing of A/X into classic to eBPF migration prologue	2015-12-18 16:04:51 -05:00
configs	kconfig: add xenconfig defconfig helper	2015-06-16 11:04:29 +01:00
debug	debug: prevent entering debug mode on panic/exception.	2015-02-19 12:39:03 -06:00
events	Merge branch 'for-4.4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup	2015-12-08 13:35:52 -08:00
gcov	gcov: add support for GCC 5.1	2015-06-30 19:44:57 -07:00
irq	Merge branches 'irq-urgent-for-linus' and 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-11-15 09:30:48 -08:00
livepatch	livepatch: x86: fix relocation computation with kASLR	2015-11-11 17:36:04 +01:00
locking	locking/osq: Fix ordering of node initialisation in osq_lock	2015-12-17 11:40:29 -08:00
power	mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM	2015-11-06 17:50:42 -08:00
printk	printk: prevent userland from spoofing kernel messages	2015-11-06 17:50:42 -08:00
rcu	Merge branches 'doc.2015.10.06a', 'percpu-rwsem.2015.10.06a' and 'torture.2015.10.06a' into HEAD	2015-10-07 16:06:25 -07:00
sched	sched/wait: Fix the signal handling fix	2015-12-13 14:30:59 -08:00
time	Merge branches 'irq-urgent-for-linus' and 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-11-15 09:30:48 -08:00
trace	Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-12-08 13:01:23 -08:00
.gitignore	certs: add .gitignore to stop git nagging about x509_certificate_list	2015-10-21 15:18:35 +01:00
acct.c	acct: check FMODE_CAN_WRITE	2015-04-11 22:27:55 -04:00
async.c
audit_fsnotify.c	audit: clean simple fsnotify implementation	2015-08-06 16:14:53 -04:00
audit_tree.c	audit: audit_tree_match can be boolean	2015-11-04 08:23:51 -05:00
audit_watch.c	Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit	2015-09-08 13:34:59 -07:00
audit.c	mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd	2015-11-06 17:50:42 -08:00
audit.h	audit: audit_tree_match can be boolean	2015-11-04 08:23:51 -05:00
auditfilter.c	audit: fix comment block whitespace	2015-11-04 08:23:51 -05:00
auditsc.c	Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit	2015-09-08 13:34:59 -07:00
backtracetest.c
bounds.c
capability.c	kernel: conditionally support non-root users, groups and capabilities	2015-04-15 16:35:22 -07:00
cgroup_freezer.c	cgroup: fix handling of multi-destination migration from subtree_control enabling	2015-12-03 10:18:21 -05:00
cgroup_pids.c	cgroup_pids: don't account for the root cgroup	2015-12-03 10:18:21 -05:00
cgroup.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2015-12-17 22:08:28 -05:00
compat.c	compat: cleanup coding in compat_get_bitmap() and compat_put_bitmap()	2015-06-04 23:57:18 +02:00
configs.c
context_tracking.c	context_tracking: avoid irq_save/irq_restore on guest entry and exit	2015-11-10 12:06:23 +01:00
cpu_pm.c	kernel/cpu_pm: fix cpu_cluster_pm_exit comment	2015-09-03 02:42:20 +02:00
cpu.c	Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-11-03 18:03:50 -08:00
cpuset.c	cgroup: fix handling of multi-destination migration from subtree_control enabling	2015-12-03 10:18:21 -05:00
crash_dump.c
cred.c	kernel/cred.c: remove unnecessary kdebug atomic reads	2015-09-10 13:29:01 -07:00
delayacct.c
dma.c
elfcore.c
exec_domain.c	Remove rest of exec domains.	2015-04-12 21:03:31 +02:00
exit.c	Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-11-03 18:03:50 -08:00
extable.c	kernel/extable.c: remove duplicated include	2015-09-10 13:29:01 -07:00
fork.c	cgroup: pids: fix race between cgroup_post_fork() and cgroup_migrate()	2015-11-30 09:48:18 -05:00
freezer.c
futex_compat.c
futex.c	driver core update for 4.4-rc1	2015-11-04 21:50:37 -08:00
groups.c	kernel: conditionally support non-root users, groups and capabilities	2015-04-15 16:35:22 -07:00
hung_task.c	kernel/hung_task.c: change hung_task.c to use for_each_process_thread()	2015-04-15 16:35:22 -07:00
irq_work.c	treewide: Remove old email address	2015-11-23 09:44:58 +01:00
jump_label.c	treewide: Remove old email address	2015-11-23 09:44:58 +01:00
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks	locking/qrwlock: Rename QUEUE_RWLOCK to QUEUED_RWLOCKS	2015-05-12 09:46:00 +02:00
Kconfig.preempt
kexec_core.c	kexec: use file name as the output message prefix	2015-11-06 17:50:42 -08:00
kexec_file.c	kexec: use file name as the output message prefix	2015-11-06 17:50:42 -08:00
kexec_internal.h	kexec: split kexec_file syscall code to kexec_file.c	2015-09-10 13:29:01 -07:00
kexec.c	kexec: use file name as the output message prefix	2015-11-06 17:50:42 -08:00
kmod.c	kmod: don't run async usermode helper as a child of kworker thread	2015-10-23 17:55:10 +09:00
kprobes.c	perf/x86/hw_breakpoints: Disallow kernel breakpoints unless kprobe-safe	2015-08-04 10:16:54 +02:00
ksysfs.c	kexec: split kexec_load syscall from kexec core code	2015-09-10 13:29:01 -07:00
kthread.c	kernel/kthread.c:kthread_create_on_node(): clarify documentation	2015-09-04 16:54:41 -07:00
latencytop.c
Makefile	sys_membarrier(): system-wide memory barrier (generic, x86)	2015-09-11 15:21:34 -07:00
membarrier.c	sys_membarrier(): system-wide memory barrier (generic, x86)	2015-09-11 15:21:34 -07:00
memremap.c	libnvdimm for 4.4:	2015-11-10 12:07:22 -08:00
module_signing.c	KEYS: Merge the type-specific data with the payload data	2015-10-21 15:18:36 +01:00
module-internal.h
module.c	module: Fix locking in symbol_put_addr()	2015-08-24 10:37:01 +09:30
notifier.c	Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-09-01 08:40:25 -07:00
nsproxy.c
padata.c	padata: use %*pb[l] to print bitmaps including cpumasks and nodemasks	2015-02-13 21:21:38 -08:00
panic.c	kernel/panic.c: turn off locks debug before releasing console lock	2015-11-20 16:17:32 -08:00
params.c	Nothing exciting, minor tweaks and cleanups.	2015-11-09 15:53:39 -08:00
pid_namespace.c
pid.c	pidns: fix NULL dereference in __task_pid_nr_ns()	2015-11-24 12:03:55 -08:00
profile.c	mm: rename alloc_pages_exact_node() to __alloc_pages_node()	2015-09-08 15:35:28 -07:00
ptrace.c	seccomp, ptrace: add support for dumping seccomp filters	2015-10-27 19:55:13 -07:00
range.c
reboot.c	kexec: split kexec_load syscall from kexec core code	2015-09-10 13:29:01 -07:00
relay.c	kernel/relay.c: use kvfree() in relay_free_page_array()	2015-06-30 19:44:59 -07:00
resource.c	mm: enhance region_is_ram() to region_intersects()	2015-08-10 23:07:05 -04:00
seccomp.c	seccomp, ptrace: add support for dumping seccomp filters	2015-10-27 19:55:13 -07:00
signal.c	kernel/signal.c: unexport sigsuspend()	2015-11-20 16:17:32 -08:00
smp.c	mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd	2015-11-06 17:50:42 -08:00
smpboot.c	stop_machine: Kill smp_hotplug_thread->pre_unpark, introduce stop_machine_unpark()	2015-10-20 10:23:55 +02:00
smpboot.h
softirq.c
stacktrace.c
stop_machine.c	kernel: remove stop_machine() Kconfig dependency	2015-12-12 10:15:34 -08:00
sys_ni.c	mm: mlock: add new mlock system call	2015-11-05 19:34:48 -08:00
sys.c	pidns: fix set/getpriority and ioprio_set/get in PRIO_USER mode	2015-11-06 17:50:42 -08:00
sysctl_binary.c
sysctl.c	kernel/watchdog.c: add sysctl knob hardlockup_panic	2015-11-05 19:34:48 -08:00
task_work.c	task_work: remove fifo ordering guarantee	2015-09-05 13:46:58 -07:00
taskstats.c
test_kprobes.c
torture.c	torture: Consolidate cond_resched_rcu_qs() into stutter_wait()	2015-10-06 11:25:01 -07:00
tracepoint.c	tracepoint: Give priority to probes of tracepoints	2015-10-25 21:33:54 -04:00
tsacct.c
uid16.c
up.c
user_namespace.c	capabilities: ambient capabilities	2015-09-04 16:54:41 -07:00
user-return-notifier.c
user.c
utsname_sysctl.c
utsname.c
watchdog.c	kernel/watchdog.c: fix race between proc_watchdog_thresh() and watchdog_timer_fn()	2015-11-05 19:34:48 -08:00
workqueue_internal.h
workqueue.c	Merge branch 'for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq	2015-11-05 14:16:27 -08:00