linux-bl808/kernel
Eric W. Biederman add0b32ef9 siginfo: Move si_trapno inside the union inside _si_fault
It turns out that linux uses si_trapno very sparingly, and as such it
can be considered extra information for a very narrow selection of
signals, rather than information that is present with every fault
reported in siginfo.

As such move si_trapno inside the union inside of _si_fault.  This
results in no change in placement, and makes it eaiser
to extend _si_fault in the future as this reduces the number of
special cases.  In particular with si_trapno included in the union it
is no longer a concern that the union must be pointer aligned on most
architectures because the union follows immediately after si_addr
which is a pointer.

This change results in a difference in siginfo field placement on
sparc and alpha for the fields si_addr_lsb, si_lower, si_upper,
si_pkey, and si_perf.  These architectures do not implement the
signals that would use si_addr_lsb, si_lower, si_upper, si_pkey, and
si_perf.  Further these architecture have not yet implemented the
userspace that would use si_perf.

The point of this change is in fact to correct these placement issues
before sparc or alpha grow userspace that cares.  This change was
discussed[1] and the agreement is that this change is currently safe.

[1]: https://lkml.kernel.org/r/CAK8P3a0+uKYwL1NhY6Hvtieghba2hKYGD6hcKx5n8=4Gtt+pHA@mail.gmail.com
Acked-by: Marco Elver <elver@google.com>
v1: https://lkml.kernel.org/r/m1tunns7yf.fsf_-_@fess.ebiederm.org
v2: https://lkml.kernel.org/r/20210505141101.11519-5-ebiederm@xmission.com
Link: https://lkml.kernel.org/r/20210517195748.8880-1-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2021-05-18 16:17:03 -05:00
..
bpf
cgroup
configs
debug
dma
entry
events
gcov
irq
kcsan
livepatch
locking Locking changes for this cycle were: 2021-04-28 12:37:53 -07:00
power
printk
rcu
sched Locking changes for this cycle were: 2021-04-28 12:37:53 -07:00
time
trace
.gitignore
acct.c
async.c
audit.c
audit.h
audit_fsnotify.c
audit_tree.c
audit_watch.c
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c
cfi.c
compat.c
configs.c
context_tracking.c
cpu.c
cpu_pm.c
crash_core.c
crash_dump.c
cred.c
delayacct.c
dma.c
exec_domain.c
exit.c
extable.c
fail_function.c
fork.c Perf events changes in this cycle were: 2021-04-28 13:03:44 -07:00
freezer.c
futex.c
gen_kheaders.sh
groups.c
hung_task.c
iomem.c
irq_work.c
jump_label.c
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c
kexec.c
kexec_core.c
kexec_elf.c
kexec_file.c
kexec_internal.h
kheaders.c
kmod.c
kprobes.c
ksysfs.c
kthread.c
latencytop.c
Makefile
module-internal.h
module.c
module_signature.c
module_signing.c
notifier.c
nsproxy.c
padata.c
panic.c
params.c
pid.c
pid_namespace.c
profile.c
ptrace.c
range.c
reboot.c
regset.c
relay.c
resource.c
resource_kunit.c
rseq.c
scftorture.c
scs.c
seccomp.c
signal.c siginfo: Move si_trapno inside the union inside _si_fault 2021-05-18 16:17:03 -05:00
smp.c
smpboot.c
smpboot.h
softirq.c RCU changes for this cycle were: 2021-04-28 12:00:13 -07:00
stackleak.c
stacktrace.c
static_call.c
stop_machine.c
sys.c
sys_ni.c
sysctl-test.c
sysctl.c
task_work.c
taskstats.c
test_kprobes.c
torture.c
tracepoint.c
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c
up.c
user-return-notifier.c
user.c
user_namespace.c
usermode_driver.c
utsname.c
utsname_sysctl.c
watch_queue.c
watchdog.c
watchdog_hld.c
workqueue.c
workqueue_internal.h