Merge 4.4.144 into android-4.4

Changes in 4.4.144
	KVM/Eventfd: Avoid crash when assign and deassign specific eventfd in parallel.
	x86/MCE: Remove min interval polling limitation
	fat: fix memory allocation failure handling of match_strdup()
	ALSA: rawmidi: Change resized buffers atomically
	ARC: Fix CONFIG_SWAP
	ARC: mm: allow mprotect to make stack mappings executable
	mm: memcg: fix use after free in mem_cgroup_iter()
	ipv4: Return EINVAL when ping_group_range sysctl doesn't map to user ns
	ipv6: fix useless rol32 call on hash
	lib/rhashtable: consider param->min_size when setting initial table size
	net/ipv4: Set oif in fib_compute_spec_dst
	net: phy: fix flag masking in __set_phy_supported
	ptp: fix missing break in switch
	tg3: Add higher cpu clock for 5762.
	net: Don't copy pfmemalloc flag in __copy_skb_header()
	skbuff: Unconditionally copy pfmemalloc in __skb_clone()
	xhci: Fix perceived dead host due to runtime suspend race with event handler
	x86/paravirt: Make native_save_fl() extern inline
	x86/cpufeatures: Add CPUID_7_EDX CPUID leaf
	x86/cpufeatures: Add Intel feature bits for Speculation Control
	x86/cpufeatures: Add AMD feature bits for Speculation Control
	x86/msr: Add definitions for new speculation control MSRs
	x86/pti: Do not enable PTI on CPUs which are not vulnerable to Meltdown
	x86/cpufeature: Blacklist SPEC_CTRL/PRED_CMD on early Spectre v2 microcodes
	x86/speculation: Add basic IBPB (Indirect Branch Prediction Barrier) support
	x86/cpufeatures: Clean up Spectre v2 related CPUID flags
	x86/cpuid: Fix up "virtual" IBRS/IBPB/STIBP feature bits on Intel
	x86/pti: Mark constant arrays as __initconst
	x86/asm/entry/32: Simplify pushes of zeroed pt_regs->REGs
	x86/entry/64/compat: Clear registers for compat syscalls, to reduce speculation attack surface
	x86/speculation: Update Speculation Control microcode blacklist
	x86/speculation: Correct Speculation Control microcode blacklist again
	x86/speculation: Clean up various Spectre related details
	x86/speculation: Fix up array_index_nospec_mask() asm constraint
	x86/speculation: Add <asm/msr-index.h> dependency
	x86/xen: Zero MSR_IA32_SPEC_CTRL before suspend
	x86/mm: Factor out LDT init from context init
	x86/mm: Give each mm TLB flush generation a unique ID
	x86/speculation: Use Indirect Branch Prediction Barrier in context switch
	x86/spectre_v2: Don't check microcode versions when running under hypervisors
	x86/speculation: Use IBRS if available before calling into firmware
	x86/speculation: Move firmware_restrict_branch_speculation_*() from C to CPP
	x86/speculation: Remove Skylake C2 from Speculation Control microcode blacklist
	selftest/seccomp: Fix the flag name SECCOMP_FILTER_FLAG_TSYNC
	selftest/seccomp: Fix the seccomp(2) signature
	xen: set cpu capabilities from xen_start_kernel()
	x86/amd: don't set X86_BUG_SYSRET_SS_ATTRS when running under Xen
	x86/nospec: Simplify alternative_msr_write()
	x86/bugs: Concentrate bug detection into a separate function
	x86/bugs: Concentrate bug reporting into a separate function
	x86/bugs: Read SPEC_CTRL MSR during boot and re-use reserved bits
	x86/bugs, KVM: Support the combination of guest and host IBRS
	x86/cpu: Rename Merrifield2 to Moorefield
	x86/cpu/intel: Add Knights Mill to Intel family
	x86/bugs: Expose /sys/../spec_store_bypass
	x86/cpufeatures: Add X86_FEATURE_RDS
	x86/bugs: Provide boot parameters for the spec_store_bypass_disable mitigation
	x86/bugs/intel: Set proper CPU features and setup RDS
	x86/bugs: Whitelist allowed SPEC_CTRL MSR values
	x86/bugs/AMD: Add support to disable RDS on Fam[15, 16, 17]h if requested
	x86/speculation: Create spec-ctrl.h to avoid include hell
	prctl: Add speculation control prctls
	x86/process: Optimize TIF checks in __switch_to_xtra()
	x86/process: Correct and optimize TIF_BLOCKSTEP switch
	x86/process: Optimize TIF_NOTSC switch
	x86/process: Allow runtime control of Speculative Store Bypass
	x86/speculation: Add prctl for Speculative Store Bypass mitigation
	nospec: Allow getting/setting on non-current task
	proc: Provide details on speculation flaw mitigations
	seccomp: Enable speculation flaw mitigations
	prctl: Add force disable speculation
	seccomp: Use PR_SPEC_FORCE_DISABLE
	seccomp: Add filter flag to opt-out of SSB mitigation
	seccomp: Move speculation migitation control to arch code
	x86/speculation: Make "seccomp" the default mode for Speculative Store Bypass
	x86/bugs: Rename _RDS to _SSBD
	proc: Use underscores for SSBD in 'status'
	Documentation/spec_ctrl: Do some minor cleanups
	x86/bugs: Fix __ssb_select_mitigation() return type
	x86/bugs: Make cpu_show_common() static
	x86/bugs: Fix the parameters alignment and missing void
	x86/cpu: Make alternative_msr_write work for 32-bit code
	x86/speculation: Use synthetic bits for IBRS/IBPB/STIBP
	x86/cpufeatures: Disentangle MSR_SPEC_CTRL enumeration from IBRS
	x86/cpufeatures: Disentangle SSBD enumeration
	x86/cpu/AMD: Fix erratum 1076 (CPB bit)
	x86/cpufeatures: Add FEATURE_ZEN
	x86/speculation: Handle HT correctly on AMD
	x86/bugs, KVM: Extend speculation control for VIRT_SPEC_CTRL
	x86/speculation: Add virtualized speculative store bypass disable support
	x86/speculation: Rework speculative_store_bypass_update()
	x86/bugs: Unify x86_spec_ctrl_{set_guest, restore_host}
	x86/bugs: Expose x86_spec_ctrl_base directly
	x86/bugs: Remove x86_spec_ctrl_set()
	x86/bugs: Rework spec_ctrl base and mask logic
	x86/speculation, KVM: Implement support for VIRT_SPEC_CTRL/LS_CFG
	x86/bugs: Rename SSBD_NO to SSB_NO
	x86/xen: Add call of speculative_store_bypass_ht_init() to PV paths
	x86/cpu: Re-apply forced caps every time CPU caps are re-read
	block: do not use interruptible wait anywhere
	clk: tegra: Fix PLL_U post divider and initial rate on Tegra30
	ubi: Introduce vol_ignored()
	ubi: Rework Fastmap attach base code
	ubi: Be more paranoid while seaching for the most recent Fastmap
	ubi: Fix races around ubi_refill_pools()
	ubi: Fix Fastmap's update_vol()
	ubi: fastmap: Erase outdated anchor PEBs during attach
	Linux 4.4.144

Change-Id: Ia3e9b2b7bc653cba68b76878d34f8fcbbc007a13
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

3 files changed, 140 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index ea6a043f5beb..50f95689ab38 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -276,6 +276,7 @@ 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
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 7c4f1da0111d..b44281ccc9fe 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2520,6 +2520,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			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.
@@ -3687,6 +3690,48 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			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=
diff --git a/Documentation/spec_ctrl.txt b/Documentation/spec_ctrl.txt
new file mode 100644
index 000000000000..32f3d55c54b7
--- /dev/null
+++ b/Documentation/spec_ctrl.txt
@@ -0,0 +1,94 @@
+===================
+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);