On Fri, 4 Jul 2025 05:56:50 +0300
Jarkko Sakkinen <jar...@kernel.org> wrote:
> On Fri, Jul 04, 2025 at 05:45:11AM +0300, Jarkko Sakkinen wrote:
...
> > Well, that was some truly misguided advice from my side so all the shame
> > here is on me :-) There's no global memzero() and neither explicit
> > version makes much sense here. Sorry about that.
> >
> > I gave it now (actual) thought, and here's what I'd propose:
> >
> > diff --git a/drivers/char/tpm/tpm_crb_ffa.c b/drivers/char/tpm/tpm_crb_ffa.c
> > index 96746d5b03e3..e769f6143a7c 100644
> > --- a/drivers/char/tpm/tpm_crb_ffa.c
> > +++ b/drivers/char/tpm/tpm_crb_ffa.c
> > @@ -203,26 +203,20 @@ static int __tpm_crb_ffa_try_send_receive(unsigned
> > long func_id,
> > msg_ops = tpm_crb_ffa->ffa_dev->ops->msg_ops;
> >
> > if (ffa_partition_supports_direct_req2_recv(tpm_crb_ffa->ffa_dev)) {
> > - memzero(&tpm_crb_ffa->direct_msg_data2,
> > - sizeof(struct ffa_send_direct_data2));
> > -
> > - tpm_crb_ffa->direct_msg_data2.data[0] = func_id;
> > - tpm_crb_ffa->direct_msg_data2.data[1] = a0;
> > - tpm_crb_ffa->direct_msg_data2.data[2] = a1;
> > - tpm_crb_ffa->direct_msg_data2.data[3] = a2;
> > + tpm_crb_ffa->direct_msg_data2 = (struct ffa_send_direct_data2){
> > + .data = { func_id, a0, a1, a2 },
> > + };
clang has a habit of compiling that as an un-named on-stack structure that
is initialised and then memcpy() used to copy it into place.
Often not was intended and blows the stack when the structure is large.
So probably not a pattern that should be encouraged.
David
