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    Subject[PATCH 4.9 124/130] PCI: OF: Fix I/O space page leak
    Date
    4.9-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>

    commit a5fb9fb023a1435f2b42bccd7f547560f3a21dc3 upstream.

    When testing the R-Car PCIe driver on the Condor board, if the PCIe PHY
    driver was left disabled, the kernel crashed with this BUG:

    kernel BUG at lib/ioremap.c:72!
    Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
    Modules linked in:
    CPU: 0 PID: 39 Comm: kworker/0:1 Not tainted 4.17.0-dirty #1092
    Hardware name: Renesas Condor board based on r8a77980 (DT)
    Workqueue: events deferred_probe_work_func
    pstate: 80000005 (Nzcv daif -PAN -UAO)
    pc : ioremap_page_range+0x370/0x3c8
    lr : ioremap_page_range+0x40/0x3c8
    sp : ffff000008da39e0
    x29: ffff000008da39e0 x28: 00e8000000000f07
    x27: ffff7dfffee00000 x26: 0140000000000000
    x25: ffff7dfffef00000 x24: 00000000000fe100
    x23: ffff80007b906000 x22: ffff000008ab8000
    x21: ffff000008bb1d58 x20: ffff7dfffef00000
    x19: ffff800009c30fb8 x18: 0000000000000001
    x17: 00000000000152d0 x16: 00000000014012d0
    x15: 0000000000000000 x14: 0720072007200720
    x13: 0720072007200720 x12: 0720072007200720
    x11: 0720072007300730 x10: 00000000000000ae
    x9 : 0000000000000000 x8 : ffff7dffff000000
    x7 : 0000000000000000 x6 : 0000000000000100
    x5 : 0000000000000000 x4 : 000000007b906000
    x3 : ffff80007c61a880 x2 : ffff7dfffeefffff
    x1 : 0000000040000000 x0 : 00e80000fe100f07
    Process kworker/0:1 (pid: 39, stack limit = 0x (ptrval))
    Call trace:
    ioremap_page_range+0x370/0x3c8
    pci_remap_iospace+0x7c/0xac
    pci_parse_request_of_pci_ranges+0x13c/0x190
    rcar_pcie_probe+0x4c/0xb04
    platform_drv_probe+0x50/0xbc
    driver_probe_device+0x21c/0x308
    __device_attach_driver+0x98/0xc8
    bus_for_each_drv+0x54/0x94
    __device_attach+0xc4/0x12c
    device_initial_probe+0x10/0x18
    bus_probe_device+0x90/0x98
    deferred_probe_work_func+0xb0/0x150
    process_one_work+0x12c/0x29c
    worker_thread+0x200/0x3fc
    kthread+0x108/0x134
    ret_from_fork+0x10/0x18
    Code: f9004ba2 54000080 aa0003fb 17ffff48 (d4210000)

    It turned out that pci_remap_iospace() wasn't undone when the driver's
    probe failed, and since devm_phy_optional_get() returned -EPROBE_DEFER,
    the probe was retried, finally causing the BUG due to trying to remap
    already remapped pages.

    Introduce the devm_pci_remap_iospace() managed API and replace the
    pci_remap_iospace() call with it to fix the bug.

    Fixes: dbf9826d5797 ("PCI: generic: Convert to DT resource parsing API")
    Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
    [lorenzo.pieralisi@arm.com: split commit/updated the commit log]
    Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
    Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
    Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
    [Backport just for the new api which other patches need - gregkh]
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/pci/pci.c | 38 ++++++++++++++++++++++++++++++++++++++
    include/linux/pci.h | 2 ++
    2 files changed, 40 insertions(+)

    --- a/drivers/pci/pci.c
    +++ b/drivers/pci/pci.c
    @@ -3436,6 +3436,44 @@ char * __weak __init pcibios_setup(char
    return str;
    }

    +static void devm_pci_unmap_iospace(struct device *dev, void *ptr)
    +{
    + struct resource **res = ptr;
    +
    + pci_unmap_iospace(*res);
    +}
    +
    +/**
    + * devm_pci_remap_iospace - Managed pci_remap_iospace()
    + * @dev: Generic device to remap IO address for
    + * @res: Resource describing the I/O space
    + * @phys_addr: physical address of range to be mapped
    + *
    + * Managed pci_remap_iospace(). Map is automatically unmapped on driver
    + * detach.
    + */
    +int devm_pci_remap_iospace(struct device *dev, const struct resource *res,
    + phys_addr_t phys_addr)
    +{
    + const struct resource **ptr;
    + int error;
    +
    + ptr = devres_alloc(devm_pci_unmap_iospace, sizeof(*ptr), GFP_KERNEL);
    + if (!ptr)
    + return -ENOMEM;
    +
    + error = pci_remap_iospace(res, phys_addr);
    + if (error) {
    + devres_free(ptr);
    + } else {
    + *ptr = res;
    + devres_add(dev, ptr);
    + }
    +
    + return error;
    +}
    +EXPORT_SYMBOL(devm_pci_remap_iospace);
    +
    /**
    * pcibios_set_master - enable PCI bus-mastering for device dev
    * @dev: the PCI device to enable
    --- a/include/linux/pci.h
    +++ b/include/linux/pci.h
    @@ -1190,6 +1190,8 @@ int pci_register_io_range(phys_addr_t ad
    unsigned long pci_address_to_pio(phys_addr_t addr);
    phys_addr_t pci_pio_to_address(unsigned long pio);
    int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr);
    +int devm_pci_remap_iospace(struct device *dev, const struct resource *res,
    + phys_addr_t phys_addr);
    void pci_unmap_iospace(struct resource *res);

    static inline pci_bus_addr_t pci_bus_address(struct pci_dev *pdev, int bar)

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