On 29 January 2016 at 15:19, Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote: > 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 > Sigh. 64 * 4 == 256 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
