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Diffstat (limited to 'Documentation/arch/arm64/sve.rst')
| -rw-r--r-- | Documentation/arch/arm64/sve.rst | 10 |
1 files changed, 2 insertions, 8 deletions
diff --git a/Documentation/arch/arm64/sve.rst b/Documentation/arch/arm64/sve.rst index 0d9a426e9f..8d8837fc39 100644 --- a/Documentation/arch/arm64/sve.rst +++ b/Documentation/arch/arm64/sve.rst @@ -117,11 +117,6 @@ the SVE instruction set architecture. * The SVE registers are not used to pass arguments to or receive results from any syscall. -* In practice the affected registers/bits will be preserved or will be replaced - with zeros on return from a syscall, but userspace should not make - assumptions about this. The kernel behaviour may vary on a case-by-case - basis. - * All other SVE state of a thread, including the currently configured vector length, the state of the PR_SVE_VL_INHERIT flag, and the deferred vector length (if any), is preserved across all syscalls, subject to the specific @@ -428,9 +423,8 @@ The regset data starts with struct user_sve_header, containing: /proc/sys/abi/sve_default_vector_length Writing the text representation of an integer to this file sets the system - default vector length to the specified value, unless the value is greater - than the maximum vector length supported by the system in which case the - default vector length is set to that maximum. + default vector length to the specified value rounded to a supported value + using the same rules as for setting vector length via PR_SVE_SET_VL. The result can be determined by reopening the file and reading its contents. |