Hello Bjorn,
On Sat, Jan 18, 2025 at 02:34:21PM -0600, Bjorn Helgaas wrote:
> On Tue, Dec 03, 2024 at 07:38:53AM +0100, Niklas Cassel wrote:
> > The test BAR is on the EP side is allocated using pci_epf_alloc_space(),
> > which allocates the backing memory using dma_alloc_coherent(), which will
> > return zeroed memory regardless of __GFP_ZERO was set or not.
>
> > +static void pci_epf_test_set_capabilities(struct pci_epf *epf)
> > +{
> > + struct pci_epf_test *epf_test = epf_get_drvdata(epf);
> > + enum pci_barno test_reg_bar = epf_test->test_reg_bar;
> > + struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
> > + struct pci_epc *epc = epf->epc;
> > + u32 caps = 0;
> > +
> > + if (epc->ops->align_addr)
> > + caps |= CAP_UNALIGNED_ACCESS;
> > +
> > + reg->caps = cpu_to_le32(caps);
>
> "make C=2 drivers/pci/" complains about this:
>
> drivers/pci/endpoint/functions/pci-epf-test.c:756:19: warning: incorrect type in assignment (different base types)
> drivers/pci/endpoint/functions/pci-epf-test.c:756:19: expected unsigned int [usertype] caps
> drivers/pci/endpoint/functions/pci-epf-test.c:756:19: got restricted __le32 [usertype]
Yes, pci-epf-test is broken when it comes to endianness, as reported here:
https://lore.kernel.org/linux-pci/ZxYHoi4mv-4eg0TK@xxxxxxxxx/
Nice to see that sparse is complaining about it! :)
Mani said that he was going to work on it, but I guess that it fell through
the cracks.
I sent patch for it here:
https://lore.kernel.org/linux-pci/20250120115009.2748899-2-cassel@xxxxxxxxxx/T/#u
FWIW, I tested it on rk3588 which is little-endian, and that still worked.
However, if you feel that it is a bit too late to queue it now, you could
also take only the following change from the patch above:
diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index ffb534a8e50a..cb7e57377214 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -76,7 +76,7 @@ struct pci_epf_test_reg {
u32 irq_type;
u32 irq_number;
u32 flags;
- u32 caps;
+ __le32 caps;
} __packed;
static struct pci_epf_header test_header = {
Kind regards,
Niklas
