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Linux kernel source tree
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Non-streaming SVE state may be preserved without an SVE payload, in
which case the SVE context only has a header with VL==0, and all state
can be restored from the FPSIMD context. Streaming SVE state is always
preserved with an SVE payload, where the SVE context header has VL!=0,
and the SVE_SIG_FLAG_SM flag is set.
The kernel never preserves an SVE context where SVE_SIG_FLAG_SM is set
without an SVE payload. However, restore_sve_fpsimd_context() doesn't
forbid restoring such a context, and will handle this case by clearing
PSTATE.SM and restoring the FPSIMD context into non-streaming mode,
which isn't consistent with the SVE_SIG_FLAG_SM flag.
Forbid this case, and mandate an SVE payload when the SVE_SIG_FLAG_SM
flag is set. This avoids an awkward ABI quirk and reduces the risk that
later rework to this code permits configuring a task with PSTATE.SM==1
and fp_type==FP_STATE_FPSIMD.
I've marked this as a fix given that we never intended to support this
case, and we don't want anyone to start relying upon the old behaviour
once we re-enable SME.
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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 reStructuredText 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.