4 Commits

Author SHA1 Message Date
Thomas Weißschuh
8af2d1ab78 admin-guide/hw-vuln/core-scheduling: fix return type of PR_SCHED_CORE_GET
sched_core_share_pid() copies the cookie to userspace with
put_user(id, (u64 __user *)uaddr), expecting 64 bits of space.
The "unsigned long" datatype that is documented in core-scheduling.rst
however is only 32 bits large on 32 bit architectures.

Document "unsigned long long" as the correct data type that is always
64bits large.

This matches what the selftest cs_prctl_test.c has been doing all along.

Fixes: 0159bb020ca9 ("Documentation: Add usecases, design and interface for core scheduling")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/util-linux/df7a25a0-7923-4f8b-a527-5e6f0064074d@t-8ch.de/
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Chris Hyser <chris.hyser@oracle.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240423-core-scheduling-cookie-v1-1-5753a35f8dfc@weissschuh.net
2024-04-24 13:04:27 -06:00
Eugene Syromiatnikov
61bc346ce6
uapi/linux/prctl: provide macro definitions for the PR_SCHED_CORE type argument
Commit 7ac592aa35a684ff ("sched: prctl() core-scheduling interface")
made use of enum pid_type in prctl's arg4; this type and the associated
enumeration definitions are not exposed to userspace.  Christian
has suggested to provide additional macro definitions that convey
the meaning of the type argument more in alignment with its actual
usage, and this patch does exactly that.

Link: https://lore.kernel.org/r/20210825170613.GA3884@asgard.redhat.com
Suggested-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
Complements: 7ac592aa35a684ff ("sched: prctl() core-scheduling interface")
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-09-29 13:00:05 +02:00
Fabio M. De Francesco
ce48ee81a1 admin-guide/hw-vuln: Rephrase a section of core-scheduling.rst
Rephrase the "For MDS" section in core-scheduling.rst for the purpose of
making it clearer what is meant by "kernel memory is still considered
untrusted".

Suggested-by: Vineeth Pillai <Vineeth.Pillai@microsoft.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: Joel Fernandes (Google) <joelaf@google.com>
Link: https://lore.kernel.org/r/20210721190250.26095-1-fmdefrancesco@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-07-25 14:39:17 -06:00
Joel Fernandes (Google)
0159bb020c Documentation: Add usecases, design and interface for core scheduling
Now that core scheduling is merged, update the documentation.

Co-developed-by: Chris Hyser <chris.hyser@oracle.com>
Signed-off-by: Chris Hyser <chris.hyser@oracle.com>
Co-developed-by: Josh Don <joshdon@google.com>
Signed-off-by: Josh Don <joshdon@google.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210603013136.370918-1-joel@joelfernandes.org
2021-06-10 09:57:09 +02:00