hi Bjorn,
On 2018/6/7 6:01, Bjorn Helgaas wrote:
> On Wed, Jun 06, 2018 at 10:06:33AM +0800, Yisheng Xie wrote:
>> Zhou reported a bug on Hisilicon arm64 D06 platform with 64KB page size:
>>
>> [ 2.470908] kernel BUG at lib/ioremap.c:72!
>> [ 2.475079] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
>> [ 2.480551] Modules linked in:
>> [ 2.483594] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.16.0-rc7-00062-g0b41260-dirty #23
>> [ 2.491756] Hardware name: Huawei D06/D06, BIOS Hisilicon D06 UEFI Nemo 2.0 RC0 - B120 03/23/2018
>> [ 2.500614] pstate: 80c00009 (Nzcv daif +PAN +UAO)
>> [ 2.505395] pc : ioremap_page_range+0x268/0x36c
>> [ 2.509912] lr : pci_remap_iospace+0xe4/0x100
>> [...]
>> [ 2.603733] Call trace:
>> [ 2.606168] ioremap_page_range+0x268/0x36c
>> [ 2.610337] pci_remap_iospace+0xe4/0x100
>> [ 2.614334] acpi_pci_probe_root_resources+0x1d4/0x214
>> [ 2.619460] pci_acpi_root_prepare_resources+0x18/0xa8
>> [ 2.624585] acpi_pci_root_create+0x98/0x214
>> [ 2.628843] pci_acpi_scan_root+0x124/0x20c
>> [ 2.633013] acpi_pci_root_add+0x224/0x494
>> [ 2.637096] acpi_bus_attach+0xf8/0x200
>> [ 2.640918] acpi_bus_attach+0x98/0x200
>> [ 2.644740] acpi_bus_attach+0x98/0x200
>> [ 2.648562] acpi_bus_scan+0x48/0x9c
>> [ 2.652125] acpi_scan_init+0x104/0x268
>> [ 2.655948] acpi_init+0x308/0x374
>> [ 2.659337] do_one_initcall+0x48/0x14c
>> [ 2.663160] kernel_init_freeable+0x19c/0x250
>> [ 2.667504] kernel_init+0x10/0x100
>> [ 2.670979] ret_from_fork+0x10/0x18
>>
>> The cause is the size of PCI IO resource is 32KB, which is 4K aligned but
>> not 64KB aligned, however, ioremap_page_range() request the range as page
>> aligned or it will trigger a BUG_ON() on ioremap_pte_range() it calls, as
>> ioremap_pte_range increase the addr by PAGE_SIZE, which makes addr != end
>> until trigger BUG_ON, if its incoming end is not page aligned. More detail
>> trace is as following:
>>
>> ioremap_page_range
>> -> ioremap_p4d_range
>> -> ioremap_p4d_range
>> -> ioremap_pud_range
>> -> ioremap_pmd_range
>> -> ioremap_pte_range
>>
>> This patch avoid panic by align the vaddr and phys_addr.
>>
>> Reported-by: Zhou Wang <wangzhou1@xxxxxxxxxxxxx>
>> Tested-by: Xiaojun Tan <tanxiaojun@xxxxxxxxxx>
>> Signed-off-by: Yisheng Xie <xieyisheng1@xxxxxxxxxx>
>> ---
>> v4:
>> - align vaddr and phys_addr - per Bjorn
>> v3:
>> - pci_remap_iospace() sanitize its arguments instead - per Rafael
>> v2:
>> - Let the caller of ioremap_page_range() align the request by PAGE_SIZE - per Toshi
>>
>> drivers/pci/pci.c | 12 +++++++++++-
>> 1 file changed, 11 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
>> index dbfe7c4..652f7d6 100644
>> --- a/drivers/pci/pci.c
>> +++ b/drivers/pci/pci.c
>> @@ -3537,6 +3537,7 @@ int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
>> {
>> #if defined(PCI_IOBASE) && defined(CONFIG_MMU)
>> unsigned long vaddr = (unsigned long)PCI_IOBASE + res->start;
>> + unsigned long last_vaddr;
>>
>> if (!(res->flags & IORESOURCE_IO))
>> return -EINVAL;
>> @@ -3544,7 +3545,16 @@ int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
>> if (res->end > IO_SPACE_LIMIT)
>> return -EINVAL;
>>
>> - return ioremap_page_range(vaddr, vaddr + resource_size(res), phys_addr,
>> + /* It will be mess if vaddr's offset is not equal to phys_addr's */
>> + if ((vaddr & ~PAGE_MASK) != (phys_addr & ~PAGE_MASK))
>> + return -EINVAL;
>> +
>> + /* Mappings have to be page-aligned */
>> + last_vaddr = PAGE_ALIGN(vaddr + resource_size(res));
>> + phys_addr &= PAGE_MASK;
>> + vaddr &= PAGE_MASK;
>
> I think this stuff should be put into ioremap_page_range(). Almost
> every caller does this sort of thing before calling
> ioremap_page_range(), so you could clean up a fair amount of code if
> you added one copy into ioremap_page_range() and removed it from all
> the callers.
Actually, I do not have strong opinion about this. Therefore, I would
like to add ./lib/ioremap.c's maintainer(commiters), to get more suggestion.
Hi Andrew, Greg and all,
Could you please give some suggestion about this patch?
Thanks
Yisheng
>
>> + return ioremap_page_range(vaddr, last_vaddr, phys_addr,
>> pgprot_device(PAGE_KERNEL));
>> #else
>> /* this architecture does not have memory mapped I/O space,
>
> .
>
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