On Thu, Oct 14, 2021 at 07:27:42AM +0000, Reshetova, Elena wrote:

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On Thu, Oct 14, 2021 at 06:32:32AM +0000, Reshetova, Elena wrote:

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On Tue, Oct 12, 2021 at 06:36:16PM +0000, Reshetova, Elena wrote:

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The 5.15 tree has something like ~2.4k IO accesses (including MMIO and
others) in init functions that also register drivers (thanks Elena for
the number)

To provide more numbers on this. What I can see so far from a smatch-based
analysis, we have 409 __init style functions (.probe & builtin/module_
_platform_driver_probe excluded) for 5.15 with allyesconfig.

I don't think we care about allyesconfig at all though.
Just don't do that.
How about allmodconfig? This is closer to what distros actually do.

It does not make any difference really for the content of the /drivers/*:
gives 408 __init style functions doing IO (.probe & builtin/module_

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_platform_driver_probe excluded) for 5.15 with allmodconfig:

['doc200x_ident_chip',
'doc_probe', 'doc2001_init', 'mtd_speedtest_init',
'mtd_nandbiterrs_init', 'mtd_oobtest_init', 'mtd_pagetest_init',
'tort_init', 'mtd_subpagetest_init', 'fixup_pmc551',
'doc_set_driver_info', 'init_amd76xrom', 'init_l440gx',
'init_sc520cdp', 'init_ichxrom', 'init_ck804xrom', 'init_esb2rom',
'probe_acpi_namespace_devices', 'amd_iommu_init_pci', 'state_next',
'arm_v7s_do_selftests', 'arm_lpae_run_tests', 'init_iommu_one',

Um. ARM? Which architecture is this build for?

The list of smatch IO findings is built for x86, but the smatch cross function
database covers all archs, so when queried for all potential function callers,
it would show non x86 arch call chains also. 

Here is the original x86 finding and call chain for the 'arm_v7s_do_selftests':

  Detected low-level IO from arm_v7s_do_selftests in fun
__iommu_queue_command_sync

drivers/iommu/amd/iommu.c:1025 __iommu_queue_command_sync() error:
{15002074744551330002}
    'check_host_input' read from the host using function 'readl' to a
member of the structure 'iommu->cmd_buf_head';

__iommu_queue_command_sync()
  iommu_completion_wait()
    amd_iommu_domain_flush_complete()
      iommu_v1_map_page()
        arm_v7s_do_selftests()

So, the results can be further filtered if you want a specified arch. 

So what is it just for x86? Could you tell?

-- 
MST