Documentation/spec_ctrl: Do some minor cleanups (dd079269) · Commits · 戴 / test

Documentation/userspace-api/spec_ctrl.rst

+12 −12

Original line number	Original line	Diff line number	Diff line
	@@ -2,13 +2,13 @@
	Speculation Control		Speculation Control
	===================		===================

	Quite some CPUs have speculation related misfeatures which are in fact		Quite some CPUs have speculation-related misfeatures which are in
	vulnerabilites causing data leaks in various forms even accross privilege		fact vulnerabilities causing data leaks in various forms even across
	domains.		privilege domains.

	The kernel provides mitigation for such vulnerabilities in various		The kernel provides mitigation for such vulnerabilities in various
	forms. Some of these mitigations are compile time configurable and some on		forms. Some of these mitigations are compile-time configurable and some
	the kernel command line.		can be supplied on the kernel command line.

	There is also a class of mitigations which are very expensive, but they can		There is also a class of mitigations which are very expensive, but they can
	be restricted to a certain set of processes or tasks in controlled		be restricted to a certain set of processes or tasks in controlled
	@@ -32,18 +32,18 @@ the following meaning:
	Bit Define Description		Bit Define Description
	==== ===================== ===================================================		==== ===================== ===================================================
	0 PR_SPEC_PRCTL Mitigation can be controlled per task by		0 PR_SPEC_PRCTL Mitigation can be controlled per task by
	PR_SET_SPECULATION_CTRL		PR_SET_SPECULATION_CTRL.
	1 PR_SPEC_ENABLE The speculation feature is enabled, mitigation is		1 PR_SPEC_ENABLE The speculation feature is enabled, mitigation is
	disabled		disabled.
	2 PR_SPEC_DISABLE The speculation feature is disabled, mitigation is		2 PR_SPEC_DISABLE The speculation feature is disabled, mitigation is
	enabled		enabled.
	3 PR_SPEC_FORCE_DISABLE Same as PR_SPEC_DISABLE, but cannot be undone. A		3 PR_SPEC_FORCE_DISABLE Same as PR_SPEC_DISABLE, but cannot be undone. A
	subsequent prctl(..., PR_SPEC_ENABLE) will fail.		subsequent prctl(..., PR_SPEC_ENABLE) will fail.
	==== ===================== ===================================================		==== ===================== ===================================================

	If all bits are 0 the CPU is not affected by the speculation misfeature.		If all bits are 0 the CPU is not affected by the speculation misfeature.

	If PR_SPEC_PRCTL is set, then the per task control of the mitigation is		If PR_SPEC_PRCTL is set, then the per-task control of the mitigation is
	available. If not set, prctl(PR_SET_SPECULATION_CTRL) for the speculation		available. If not set, prctl(PR_SET_SPECULATION_CTRL) for the speculation
	misfeature will fail.		misfeature will fail.

	@@ -61,9 +61,9 @@ Common error codes
	Value Meaning		Value Meaning
	======= =================================================================		======= =================================================================
	EINVAL The prctl is not implemented by the architecture or unused		EINVAL The prctl is not implemented by the architecture or unused
	prctl(2) arguments are not 0		prctl(2) arguments are not 0.

	ENODEV arg2 is selecting a not supported speculation misfeature		ENODEV arg2 is selecting a not supported speculation misfeature.
	======= =================================================================		======= =================================================================

	PR_SET_SPECULATION_CTRL error codes		PR_SET_SPECULATION_CTRL error codes
	@@ -74,7 +74,7 @@ Value Meaning
	0 Success		0 Success

	ERANGE arg3 is incorrect, i.e. it's neither PR_SPEC_ENABLE nor		ERANGE arg3 is incorrect, i.e. it's neither PR_SPEC_ENABLE nor
	PR_SPEC_DISABLE nor PR_SPEC_FORCE_DISABLE		PR_SPEC_DISABLE nor PR_SPEC_FORCE_DISABLE.

	ENXIO Control of the selected speculation misfeature is not possible.		ENXIO Control of the selected speculation misfeature is not possible.
	See PR_GET_SPECULATION_CTRL.		See PR_GET_SPECULATION_CTRL.

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