Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net (5b79c2af) · Commits · e / devices / android_kernel_teracube_emerald

Documentation/ABI/testing/sysfs-devices-system-cpu

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		@@ -478,6 +478,7 @@ What: /sys/devices/system/cpu/vulnerabilities
		/sys/devices/system/cpu/vulnerabilities/meltdown
		/sys/devices/system/cpu/vulnerabilities/spectre_v1
		/sys/devices/system/cpu/vulnerabilities/spectre_v2
		/sys/devices/system/cpu/vulnerabilities/spec_store_bypass
		Date: January 2018
		Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
		Description: Information about CPU vulnerabilities

Documentation/admin-guide/kernel-parameters.txt

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		@@ -2680,6 +2680,9 @@
		allow data leaks with this option, which is equivalent
		to spectre_v2=off.

		nospec_store_bypass_disable
		[HW] Disable all mitigations for the Speculative Store Bypass vulnerability

		noxsave [BUGS=X86] Disables x86 extended register state save
		and restore using xsave. The kernel will fallback to
		enabling legacy floating-point and sse state.
		@@ -4025,6 +4028,48 @@
		Not specifying this option is equivalent to
		spectre_v2=auto.

		spec_store_bypass_disable=
		[HW] Control Speculative Store Bypass (SSB) Disable mitigation
		(Speculative Store Bypass vulnerability)

		Certain CPUs are vulnerable to an exploit against a
		a common industry wide performance optimization known
		as "Speculative Store Bypass" in which recent stores
		to the same memory location may not be observed by
		later loads during speculative execution. The idea
		is that such stores are unlikely and that they can
		be detected prior to instruction retirement at the
		end of a particular speculation execution window.

		In vulnerable processors, the speculatively forwarded
		store can be used in a cache side channel attack, for
		example to read memory to which the attacker does not
		directly have access (e.g. inside sandboxed code).

		This parameter controls whether the Speculative Store
		Bypass optimization is used.

		on - Unconditionally disable Speculative Store Bypass
		off - Unconditionally enable Speculative Store Bypass
		auto - Kernel detects whether the CPU model contains an
		implementation of Speculative Store Bypass and
		picks the most appropriate mitigation. If the
		CPU is not vulnerable, "off" is selected. If the
		CPU is vulnerable the default mitigation is
		architecture and Kconfig dependent. See below.
		prctl - Control Speculative Store Bypass per thread
		via prctl. Speculative Store Bypass is enabled
		for a process by default. The state of the control
		is inherited on fork.
		seccomp - Same as "prctl" above, but all seccomp threads
		will disable SSB unless they explicitly opt out.

		Not specifying this option is equivalent to
		spec_store_bypass_disable=auto.

		Default mitigations:
		X86: If CONFIG_SECCOMP=y "seccomp", otherwise "prctl"

		spia_io_base= [HW,MTD]
		spia_fio_base=
		spia_pedr=

Documentation/networking/ppp_generic.txt

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		@@ -300,12 +300,6 @@ unattached instance are:
		The ioctl calls available on an instance of /dev/ppp attached to a
		channel are:

		* PPPIOCDETACH detaches the instance from the channel. This ioctl is
		deprecated since the same effect can be achieved by closing the
		instance. In order to prevent possible races this ioctl will fail
		with an EINVAL error if more than one file descriptor refers to this
		instance (i.e. as a result of dup(), dup2() or fork()).

		* PPPIOCCONNECT connects this channel to a PPP interface. The
		argument should point to an int containing the interface unit
		number. It will return an EINVAL error if the channel is already

Documentation/userspace-api/index.rst

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		@@ -19,6 +19,7 @@ place where this information is gathered.
		no_new_privs
		seccomp_filter
		unshare
		spec_ctrl

		.. only:: subproject and html

Documentation/userspace-api/spec_ctrl.rst

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		===================
		Speculation Control
		===================

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

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

		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
		environments. The mechanism to control these mitigations is via
		:manpage:`prctl(2)`.

		There are two prctl options which are related to this:

		* PR_GET_SPECULATION_CTRL

		* PR_SET_SPECULATION_CTRL

		PR_GET_SPECULATION_CTRL
		-----------------------

		PR_GET_SPECULATION_CTRL returns the state of the speculation misfeature
		which is selected with arg2 of prctl(2). The return value uses bits 0-3 with
		the following meaning:

		==== ===================== ===================================================
		Bit Define Description
		==== ===================== ===================================================
		0 PR_SPEC_PRCTL Mitigation can be controlled per task by
		PR_SET_SPECULATION_CTRL.
		1 PR_SPEC_ENABLE The speculation feature is enabled, mitigation is
		disabled.
		2 PR_SPEC_DISABLE The speculation feature is disabled, mitigation is
		enabled.
		3 PR_SPEC_FORCE_DISABLE Same as PR_SPEC_DISABLE, but cannot be undone. A
		subsequent prctl(..., PR_SPEC_ENABLE) will fail.
		==== ===================== ===================================================

		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
		available. If not set, prctl(PR_SET_SPECULATION_CTRL) for the speculation
		misfeature will fail.

		PR_SET_SPECULATION_CTRL
		-----------------------

		PR_SET_SPECULATION_CTRL allows to control the speculation misfeature, which
		is selected by arg2 of :manpage:`prctl(2)` per task. arg3 is used to hand
		in the control value, i.e. either PR_SPEC_ENABLE or PR_SPEC_DISABLE or
		PR_SPEC_FORCE_DISABLE.

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

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

		PR_SET_SPECULATION_CTRL error codes
		-----------------------------------
		======= =================================================================
		Value Meaning
		======= =================================================================
		0 Success

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

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

		EPERM Speculation was disabled with PR_SPEC_FORCE_DISABLE and caller
		tried to enable it again.
		======= =================================================================

		Speculation misfeature controls
		-------------------------------
		- PR_SPEC_STORE_BYPASS: Speculative Store Bypass

		Invocations:
		* prctl(PR_GET_SPECULATION_CTRL, PR_SPEC_STORE_BYPASS, 0, 0, 0);
		* prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_STORE_BYPASS, PR_SPEC_ENABLE, 0, 0);
		* prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_STORE_BYPASS, PR_SPEC_DISABLE, 0, 0);
		* prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_STORE_BYPASS, PR_SPEC_FORCE_DISABLE, 0, 0);