95ac5bf4e4
Note this crash is present before any of the patches in this series, but as explained below it is highly unlikely anyone is shipping a firmware that causes it. Tests were done using an overriden SRAT. On ARM64, the gic-v3 driver directly parses SRAT to locate GIC Interrupt Translation Service (ITS) Affinity Structures. This is done much later in the boot than the parses of SRAT which identify proximity domains. As a result, an ITS placed in a proximity domain that is not defined by another SRAT structure will result in a NUMA node that is not completely configured and a crash. ITS [mem 0x202100000-0x20211ffff] ITS@0x0000000202100000: Using ITS number 0 Unable to handle kernel paging request at virtual address 0000000000001a08 ... Call trace: __alloc_pages_nodemask+0xe8/0x338 alloc_pages_node.constprop.0+0x34/0x40 its_probe_one+0x2f8/0xb18 gic_acpi_parse_madt_its+0x108/0x150 acpi_table_parse_entries_array+0x17c/0x264 acpi_table_parse_entries+0x48/0x6c acpi_table_parse_madt+0x30/0x3c its_init+0x1c4/0x644 gic_init_bases+0x4b8/0x4ec gic_acpi_init+0x134/0x264 acpi_match_madt+0x4c/0x84 acpi_table_parse_entries_array+0x17c/0x264 acpi_table_parse_entries+0x48/0x6c acpi_table_parse_madt+0x30/0x3c __acpi_probe_device_table+0x8c/0xe8 irqchip_init+0x3c/0x48 init_IRQ+0xcc/0x100 start_kernel+0x33c/0x548 ACPI 6.3 allows any set of Affinity Structures in SRAT to define a proximity domain. However, as we do not see this crash, we can conclude that no firmware is currently placing an ITS in a node that is separate from those containing memory and / or processors. We could modify the SRAT parsing behavior to identify the existence of Proximity Domains unique to the ITS structures, and handle them as a special case of a generic initiator (once support for those merges). This patch avoids the complexity that would be needed to handle this corner case, by not allowing the ITS entry parsing code to instantiate new NUMA Nodes. If one is encountered that does not already exist, then NO_NUMA_NODE is assigned and a warning printed just as if the value had been greater than allowed NUMA Nodes. "SRAT: Invalid NUMA node -1 in ITS affinity" Whilst this does not provide the full flexibility allowed by ACPI, it does fix the problem. We can revisit a more sophisticated solution if needed by future platforms. Change is simply to replace acpi_map_pxm_to_node with pxm_to_node reflecting the fact a new mapping is not created. Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Hanjun Guo <guohanjun@huawei.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.