[PATCH v3] arm64: Expose the end of the linear map in PHYSMEM_END

[Andy Shevchenko]

On Tue, Sep 03, 2024 at 09:45:32AM -0700, D Scott Phillips wrote:
> The memory hot-plug and resource management code needs to know the
> largest address which can fit in the linear map, so set
> PHYSMEM_END for that purpose.
> 
> This fixes a crash[1] at boot when amdgpu tries to create
> DEVICE_PRIVATE_MEMORY and is given a physical address by the
> resource management code which is outside the range which can have
> a `struct page`
> 
> The Fixes: commit listed below isn't actually broken, but the
> reorganization of vmemmap causes the improper DEVICE_PRIVATE_MEMORY address
> to go from a warning to a crash.
> 
> [1]: Unable to handle kernel paging request at virtual address

No need to have [1]: prefix here and also read this
https://www.kernel.org/doc/html/latest/process/submitting-patches.html#backtraces-in-commit-messages
and amend commit message accordingly.

>      000001ffa6000034
>      Mem abort info:
>        ESR = 0x0000000096000044
>        EC = 0x25: DABT (current EL), IL = 32 bits
>        SET = 0, FnV = 0
>        EA = 0, S1PTW = 0
>        FSC = 0x04: level 0 translation fault
>      Data abort info:
>        ISV = 0, ISS = 0x00000044, ISS2 = 0x00000000
>        CM = 0, WnR = 1, TnD = 0, TagAccess = 0
>        GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
>      user pgtable: 4k pages, 48-bit VAs, pgdp=000008000287c000
>      [000001ffa6000034] pgd=0000000000000000, p4d=0000000000000000
>      Call trace:
>       __init_zone_device_page.constprop.0+0x2c/0xa8
>       memmap_init_zone_device+0xf0/0x210
>       pagemap_range+0x1e0/0x410
>       memremap_pages+0x18c/0x2e0
>       devm_memremap_pages+0x30/0x90
>       kgd2kfd_init_zone_device+0xf0/0x200 [amdgpu]
>       amdgpu_device_ip_init+0x674/0x888 [amdgpu]
>       amdgpu_device_init+0x7a4/0xea0 [amdgpu]
>       amdgpu_driver_load_kms+0x28/0x1c0 [amdgpu]
>       amdgpu_pci_probe+0x1a0/0x560 [amdgpu]
>       local_pci_probe+0x48/0xb8
>       work_for_cpu_fn+0x24/0x40
>       process_one_work+0x170/0x3e0
>       worker_thread+0x2ac/0x3e0
>       kthread+0xf4/0x108
>       ret_from_fork+0x10/0x20

-- 
With Best Regards,
Andy Shevchenko