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.
> + 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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