Message ID | 1337754877-19759-3-git-send-email-yinghai@kernel.org |
---|---|
State | Rejected |
Headers | show |
On Tue, May 22, 2012 at 11:34 PM, Yinghai Lu <yinghai@kernel.org> wrote:
> and will fall back to below 4g if it can not find any above 4g.
Has this been tested on 32-bit machines without PAE? There might be
things that just happen to work because their allocations were always
done bottom-up.
Or do we have something else that protects us from the "oops, we can't
actually *map* those pages"?
Linus
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On Wed, May 23, 2012 at 8:57 AM, Linus Torvalds <torvalds@linux-foundation.org> wrote: > On Tue, May 22, 2012 at 11:34 PM, Yinghai Lu <yinghai@kernel.org> wrote: >> and will fall back to below 4g if it can not find any above 4g. > > Has this been tested on 32-bit machines without PAE? There might be > things that just happen to work because their allocations were always > done bottom-up. Good point. that problem should be addressed at first before this patch. > > Or do we have something else that protects us from the "oops, we can't > actually *map* those pages"? Steven tested on his setup. I tested some Infiniband cards. Thanks Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, May 23, 2012 at 10:30 AM, Yinghai Lu <yinghai@kernel.org> wrote: > On Wed, May 23, 2012 at 8:57 AM, Linus Torvalds > <torvalds@linux-foundation.org> wrote: >> On Tue, May 22, 2012 at 11:34 PM, Yinghai Lu <yinghai@kernel.org> wrote: >>> and will fall back to below 4g if it can not find any above 4g. >> >> Has this been tested on 32-bit machines without PAE? There might be >> things that just happen to work because their allocations were always >> done bottom-up. > > Good point. that problem should be addressed at first before this patch. Just checked code for 32bit machines without PAE. when X86_PAE is not set, phys_addr_t aka resource_size_t will be 32bit. so in drivers/pci/bus.c::pci_bus_alloc_resource_fit() will have bottom to 0. resource_size_t bottom = PCIBIOS_MAX_MEM_32 + 1ULL; also in arch/x86/kernel/setup.c::setup_arch() iomem_resource.end = (1ULL << boot_cpu_data.x86_phys_bits) - 1; will have iomem_resource.end to 0xffffffff when X86_PAE is set, but CPU does not support PAE. phys_addr_t aka resource_size_t will be 32bit. so in drivers/pci/bus.c::pci_bus_alloc_resource_fit() will have bottom to 4g. resource_size_t bottom = PCIBIOS_MAX_MEM_32 + 1ULL; but in arch/x86/kernel/setup.c::setup_arch() iomem_resource.end = (1ULL << boot_cpu_data.x86_phys_bits) - 1; will have iomem_resource.end to 0xffffffff, because x86_phys_bits is 32 when PAE is not detected in arch/x86/kernel/cpu/common.c::get_cpu_cap. that mean first try will fail, so it will go to second try with bottom to 0. so both case are safe with this patch. Thanks Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c index 4ce5ef2..2429f1f 100644 --- a/drivers/pci/bus.c +++ b/drivers/pci/bus.c @@ -122,13 +122,17 @@ pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res, int i, ret = -ENOMEM; struct resource *r; resource_size_t max = -1; + resource_size_t bottom = PCIBIOS_MAX_MEM_32 + 1ULL; type_mask |= IORESOURCE_IO | IORESOURCE_MEM; /* don't allocate too high if the pref mem doesn't support 64bit*/ - if (!(res->flags & IORESOURCE_MEM_64)) + if (!(res->flags & IORESOURCE_MEM_64)) { max = PCIBIOS_MAX_MEM_32; + bottom = 0; + } +again: pci_bus_for_each_resource(bus, r, i) { if (!r) continue; @@ -145,12 +149,18 @@ pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res, /* Ok, try it out.. */ ret = allocate_resource(r, res, size, - r->start ? : min, + max(bottom, r->start ? : min), max, align, alignf, alignf_data); if (ret == 0) - break; + return 0; } + + if (bottom != 0) { + bottom = 0; + goto again; + } + return ret; }
and will fall back to below 4g if it can not find any above 4g. Signed-off-by: Yinghai Lu <yinghai@kernel.org> --- drivers/pci/bus.c | 16 +++++++++++++--- 1 files changed, 13 insertions(+), 3 deletions(-)