On 29 January 2016 at 15:17, Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote: > Instead of iterating over the PCI config window and performing individual > ioremap() calls on all the adjacent slices, perform a single ioremap() to > map the entire region, and divvy it up later. This not only prevents > leaving some of it mapped if we fail half way through, it also ensures that > archs that support huge-vmap can use section mappings to perform the > mapping. > > On my Seattle A0 box, this transforms 128 separate 1 MB mappings that are > mapped down to 4 KB pages into a single 128 MB mapping using 2 MB sections, > saving 512 KB worth of page tables. > OK, this math is slightly off: 4 KB for each 2 MB section == 64 * 4 == 128 KB > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> > --- > > huge-vmap for arm64 proposed here: > http://article.gmane.org/gmane.linux.kernel.hardened.devel/1661 > > drivers/pci/host/pci-host-generic.c | 12 +++++++----- > 1 file changed, 7 insertions(+), 5 deletions(-) > > diff --git a/drivers/pci/host/pci-host-generic.c b/drivers/pci/host/pci-host-generic.c > index 1652bc70b145..3251cd779278 100644 > --- a/drivers/pci/host/pci-host-generic.c > +++ b/drivers/pci/host/pci-host-generic.c > @@ -161,6 +161,7 @@ static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci) > struct device *dev = pci->host.dev.parent; > struct device_node *np = dev->of_node; > u32 sz = 1 << pci->cfg.ops->bus_shift; > + void *window; > > err = of_address_to_resource(np, 0, &pci->cfg.res); > if (err) { > @@ -186,14 +187,15 @@ static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci) > return -ENOMEM; > > bus_range = pci->cfg.bus_range; > + window = devm_ioremap(dev, pci->cfg.res.start, > + (bus_range->end - bus_range->start + 1) * sz); > + if (!window) > + return -ENOMEM; > + > for (busn = bus_range->start; busn <= bus_range->end; ++busn) { > u32 idx = busn - bus_range->start; > > - pci->cfg.win[idx] = devm_ioremap(dev, > - pci->cfg.res.start + idx * sz, > - sz); > - if (!pci->cfg.win[idx]) > - return -ENOMEM; > + pci->cfg.win[idx] = window + idx * sz; > } > > return 0; > -- > 2.5.0 > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
