|
HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|
|
NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | STANDARDS | HISTORY | SEE ALSO | COLOPHON |
|
|
|
PR_GET_SPECULATION_CTRL(2const) PR_GET_SPECULATION_CTRL(2const)
PR_GET_SPECULATION_CTRL - get the state of a speculation
misfeature for the calling thread
Standard C library (libc, -lc)
#include <linux/prctl.h> /* Definition of PR_* constants */
#include <sys/prctl.h>
int prctl(PR_GET_SPECULATION_CTRL, long misfeature, 0L, 0L, 0L);
Return the state of the speculation misfeature specified in
misfeature.
Currently, misfeature must be one of:
PR_SPEC_STORE_BYPASS
Get the state of the speculative store bypass misfeature.
PR_SPEC_INDIRECT_BRANCH (since Linux 4.20)
Get the state of the indirect branch speculation
misfeature.
The return value uses bits 0-4 with the following meaning:
PR_SPEC_PRCTL
Mitigation can be controlled per thread by
PR_SET_SPECULATION_CTRL(2const).
PR_SPEC_ENABLE
The speculation feature is enabled, mitigation is disabled.
PR_SPEC_DISABLE
The speculation feature is disabled, mitigation is enabled.
PR_SPEC_FORCE_DISABLE
Same as PR_SPEC_DISABLE but cannot be undone.
PR_SPEC_DISABLE_NOEXEC (since Linux 5.1)
Same as PR_SPEC_DISABLE, but the state will be cleared on
execve(2).
If all bits are 0, then the CPU is not affected by the speculation
misfeature.
If PR_SPEC_PRCTL is set, then per-thread control of the mitigation
is available. If not set, PR_SET_SPECULATION_CTRL(2const) for the
speculation misfeature will fail.
On success, PR_GET_SPECULATION_CTRL returns the nonnegative value
described above. On error, -1 is returned, and errno is set to
indicate the error.
ENODEV The kernel or CPU does not support the requested
speculation misfeature.
Linux.
Linux 4.17.
prctl(2), PR_SET_SPECULATION_CTRL(2const)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.15.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2025-08-11. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.15 2025-05-17PR_GET_SPECULATION_CTRL(2const)
Pages that refer to this page: prctl(2), PR_SET_SPECULATION_CTRL(2const)
|
HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|