- 19 Sep, 2018 25 commits
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Nicholas Piggin authored
Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Reviewed-by:
Joel Stanley <joel@jms.id.au> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Nicholas Piggin authored
Signed-off-by:
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Nicholas Piggin authored
GCC 4.6 is the minimum supported now. Signed-off-by:
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Nicholas Piggin authored
When switching processes, currently all user SLBEs are cleared, and a few (exec_base, pc, and stack) are preloaded. In trivial testing with small apps, this tends to miss the heap and low 256MB segments, and it will also miss commonly accessed segments on large memory workloads. Add a simple round-robin preload cache that just inserts the last SLB miss into the head of the cache and preloads those at context switch time. Every 256 context switches, the oldest entry is removed from the cache to shrink the cache and require fewer slbmte if they are unused. Much more could go into this, including into the SLB entry reclaim side to track some LRU information etc, which would require a study of large memory workloads. But this is a simple thing we can do now that is an obvious win for common workloads. With the full series, process switching speed on the context_switch benchmark on POWER9/hash (with kernel speculation security masures disabled) increases from 140K/s to 178K/s (27%). POWER8 does not change much (within 1%), it's unclear why it does not see a big gain like POWER9. Booting to busybox init with 256MB segments has SLB misses go down from 945 to 69, and with 1T segments 900 to 21. These could almost all be eliminated by preloading a bit more carefully with ELF binary loading. Signed-off-by:
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Nicholas Piggin authored
This will be used by the SLB code in the next patch, but for now this sets the slb_addr_limit to the correct size for 32-bit tasks. Signed-off-by:
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Nicholas Piggin authored
Signed-off-by:
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Nicholas Piggin authored
Add 32-entry bitmaps to track the allocation status of the first 32 SLB entries, and whether they are user or kernel entries. These are used to allocate free SLB entries first, before resorting to the round robin allocator. Signed-off-by:
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Nicholas Piggin authored
User SLB mappig data is copied into the PACA from the mm->context so it can be accessed by the SLB miss handlers. After the C conversion, SLB miss handlers now run with relocation on, and user SLB misses are able to take recursive kernel SLB misses, so the user SLB mapping data can be removed from the paca and accessed directly. Signed-off-by:
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Nicholas Piggin authored
This patch moves SLB miss handlers completely to C, using the standard exception handler macros to set up the stack and branch to C. This can be done because the segment containing the kernel stack is always bolted, so accessing it with relocation on will not cause an SLB exception. Arbitrary kernel memory may not be accessed when handling kernel space SLB misses, so care should be taken there. However user SLB misses can access any kernel memory, which can be used to move some fields out of the paca (in later patches). User SLB misses could quite easily reconcile IRQs and set up a first class kernel environment and exit via ret_from_except, however that doesn't seem to be necessary at the moment, so we only do that if a bad fault is encountered. [ Credit to Aneesh for bug fixes, error checks, and improvements to bad address handling, etc ] Signed-off-by:
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Nicholas Piggin authored
POWER9 introduces SLBIA IH=3, which invalidates all SLB entries and associated lookaside information that have a class value of 1, which Linux assigns to user addresses. This matches what switch_slb wants, and allows a simple fast implementation that avoids the slb_cache complexity. As a side-effect, the POWER5 < DD2.1 SLB invalidation workaround is also avoided on POWER9. Process context switching rate is improved about 2.2% for a small process that hits the slb cache which is the best case for the current code. Signed-off-by:
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Nicholas Piggin authored
The SLBIA IH=1 hint will remove all non-zero SLBEs, but only invalidate ERAT entries associated with a class value of 1, for processors that support the hint (e.g., POWER6 and newer), which Linux assigns to user addresses. This prevents kernel ERAT entries from being invalidated when context switchig (if the thread faulted in more than 8 user SLBEs). Signed-off-by:
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Nicholas Piggin authored
Remove the vmalloc segment from bolted SLBEs. This is not required to be bolted, and seems like it was added to help pre-load the SLB on context switch. However there are now other segments like the vmemmap segment and non-zero node memory that often take misses after a context switch, so it is better to solve this in a more general way. A subsequent change will track free SLB entries and uses those rather than round-robin overwrite valid entries, which makes it far less likely for kernel SLBEs to be evicted after they are installed. Signed-off-by:
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Nicholas Piggin authored
The POWER5 < DD2.1 issue is that slbie needs to be issued more than once. It came in with this change: ChangeSet@1.1608, 2004-04-29 07:12:31-07:00, david@gibson.dropbear.id.au [PATCH] POWER5 erratum workaround Early POWER5 revisions (<DD2.1) have a problem requiring slbie instructions to be repeated under some circumstances. The patch below adds a workaround (patch made by Anton Blanchard). (aka. 3e4520f7605243abf66a7ccd3d2e49e48e8c0483 in the full history tree) The extra slbie in switch_slb is done even for the case where slbia is called (slb_flush_and_rebolt). I don't believe that is required because there are other slb_flush_and_rebolt callers which do not issue the workaround slbie, which would be broken if it was required. It also seems to be fine inside the isync with the first slbie, as it is in the kernel stack switch code. So move this workaround to where it is required. This is not much of an optimisation because this is the fast path, but it makes the code more understandable and neater. Signed-off-by:
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Nicholas Piggin authored
I only have POWER8/9 to test, so just remove it for those. Signed-off-by:
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Nicholas Piggin authored
This causes SLB alloation to start 1 beyond the start of the SLB. There is no real problem because after it wraps it stats behaving properly, it's just surprisig to see when looking at SLB traces. Signed-off-by:
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Mahesh Salgaonkar authored
Now that other platforms also implements real mode mce handler, lets consolidate the code by sharing existing powernv machine check early code. Rename machine_check_powernv_early to machine_check_common_early and reuse the code. Signed-off-by:
Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by:
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Mahesh Salgaonkar authored
If we get a machine check exceptions due to SLB errors then dump the current SLB contents which will be very much helpful in debugging the root cause of SLB errors. Introduce an exclusive buffer per cpu to hold faulty SLB entries. In real mode mce handler saves the old SLB contents into this buffer accessible through paca and print it out later in virtual mode. With this patch the console will log SLB contents like below on SLB MCE errors: [ 507.297236] SLB contents of cpu 0x1 [ 507.297237] Last SLB entry inserted at slot 16 [ 507.297238] 00 c000000008000000 400ea1b217000500 [ 507.297239] 1T ESID= c00000 VSID= ea1b217 LLP:100 [ 507.297240] 01 d000000008000000 400d43642f000510 [ 507.297242] 1T ESID= d00000 VSID= d43642f LLP:110 [ 507.297243] 11 f000000008000000 400a86c85f000500 [ 507.297244] 1T ESID= f00000 VSID= a86c85f LLP:100 [ 507.297245] 12 00007f0008000000 4008119624000d90 [ 507.297246] 1T ESID= 7f VSID= 8119624 LLP:110 [ 507.297247] 13 0000000018000000 00092885f5150d90 [ 507.297247] 256M ESID= 1 VSID= 92885f5150 LLP:110 [ 507.297248] 14 0000010008000000 4009e7cb50000d90 [ 507.297249] 1T ESID= 1 VSID= 9e7cb50 LLP:110 [ 507.297250] 15 d000000008000000 400d43642f000510 [ 507.297251] 1T ESID= d00000 VSID= d43642f LLP:110 [ 507.297252] 16 d000000008000000 400d43642f000510 [ 507.297253] 1T ESID= d00000 VSID= d43642f LLP:110 [ 507.297253] ---------------------------------- [ 507.297254] SLB cache ptr value = 3 [ 507.297254] Valid SLB cache entries: [ 507.297255] 00 EA[0-35]= 7f000 [ 507.297256] 01 EA[0-35]= 1 [ 507.297257] 02 EA[0-35]= 1000 [ 507.297257] Rest of SLB cache entries: [ 507.297258] 03 EA[0-35]= 7f000 [ 507.297258] 04 EA[0-35]= 1 [ 507.297259] 05 EA[0-35]= 1000 [ 507.297260] 06 EA[0-35]= 12 [ 507.297260] 07 EA[0-35]= 7f000 Suggested-by:
Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Suggested-by:
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Mahesh Salgaonkar authored
Extract the MCE error details from RTAS extended log and display it to console. With this patch you should now see mce logs like below: [ 142.371818] Severe Machine check interrupt [Recovered] [ 142.371822] NIP [d00000000ca301b8]: init_module+0x1b8/0x338 [bork_kernel] [ 142.371822] Initiator: CPU [ 142.371823] Error type: SLB [Multihit] [ 142.371824] Effective address: d00000000ca70000 Signed-off-by:
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Mahesh Salgaonkar authored
On pseries, as of today system crashes if we get a machine check exceptions due to SLB errors. These are soft errors and can be fixed by flushing the SLBs so the kernel can continue to function instead of system crash. We do this in real mode before turning on MMU. Otherwise we would run into nested machine checks. This patch now fetches the rtas error log in real mode and flushes the SLBs on SLB/ERAT errors. Signed-off-by:
Michal Suchanek <msuchanek@suse.com> Reviewed-by:
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Mahesh Salgaonkar authored
On pseries, the machine check error details are part of RTAS extended event log passed under Machine check exception section. This patch adds the definition of rtas MCE event section and related helper functions. Signed-off-by:
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Breno Leitao authored
There are cases where the test is not expecting to have the transaction aborted, but, the test process might have been rescheduled, either in the OS level or by KVM (if it is running on a KVM guest machine). The process reschedule will cause a treclaim/recheckpoint which will cause the transaction to doom, aborting the transaction as soon as the process is rescheduled back to the CPU. This might cause the test to fail, but this is not a failure in essence. If that is the case, TEXASR[FC] is indicated with either TM_CAUSE_RESCHEDULE or TM_CAUSE_KVM_RESCHEDULE for KVM interruptions. In this scenario, ignore these two failures and avoid the whole test to return failure. Signed-off-by:
Breno Leitao <leitao@debian.org> Reviewed-by:
Gustavo Romero <gromero@linux.ibm.com> Signed-off-by:
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Breno Leitao authored
The tbl pointer is being derefenced by IOMMU_PAGE_SIZE prior the check if it is not NULL. Just moving the dereference code to after the check, where there will be guarantee that 'tbl' will not be NULL. Signed-off-by:
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Breno Leitao authored
Function xive_native_get_ipi() might use chip_id without it being initialized, if the CPU node is not found, as reported by smatch: error: uninitialized symbol 'chip_id' As suggested by Cédric, we can use xc->chip_id instead of consulting the device tree for chip id, which is safe since xive_prepare_cpu() should have initialized ->chip_id by the time xive_native_get_ipi() is called. Signed-off-by:
Cédric Le Goater <clg@kaod.org> [mpe: Tweak change log] Signed-off-by:
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Christophe Lombard authored
The AFU Information DVSEC capability is a means to extract common, general information about all of the AFUs associated with a Function independent of the specific functionality that each AFU provides. Write in the AFU Index field allows to access to the descriptor data for each AFU. With the current code, we are not able to access to these specific data when the index >= 1 because we are writing to the wrong location. All requests to the data of each AFU are pointing to those of the AFU 0, which could have impacts when using a card with more than one AFU per function. This patch fixes the access to the AFU Descriptor Data indexed by the AFU Info Index field. Fixes: 5ef3166e ("ocxl: Driver code for 'generic' opencapi devices") Cc: stable <stable@vger.kernel.org> # 4.16 Signed-off-by:
Christophe Lombard <clombard@linux.vnet.ibm.com> Acked-by:
Frederic Barrat <fbarrat@linux.vnet.ibm.com> Acked-by:
Andrew Donnellan <andrew.donnellan@au1.ibm.com> Signed-off-by:
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Rashmica Gupta authored
When hot-removing memory release_mem_region_adjustable() splits iomem resources if they are not the exact size of the memory being hot-deleted. Adding this memory back to the kernel adds a new resource. Eg a node has memory 0x0 - 0xfffffffff. Hot-removing 1GB from 0xf40000000 results in the single resource 0x0-0xfffffffff being split into two resources: 0x0-0xf3fffffff and 0xf80000000-0xfffffffff. When we hot-add the memory back we now have three resources: 0x0-0xf3fffffff, 0xf40000000-0xf7fffffff, and 0xf80000000-0xfffffffff. This is an issue if we try to remove some memory that overlaps resources. Eg when trying to remove 2GB at address 0xf40000000, release_mem_region_adjustable() fails as it expects the chunk of memory to be within the boundaries of a single resource. We then get the warning: "Unable to release resource" and attempting to use memtrace again gives us this error: "bash: echo: write error: Resource temporarily unavailable" This patch makes memtrace remove memory in chunks that are always the same size from an address that is always equal to end_of_memory - n*size, for some n. So hotremoving and hotadding memory of different sizes will now not attempt to remove memory that spans multiple resources. Signed-off-by:
Rashmica Gupta <rashmica.g@gmail.com> Signed-off-by:
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- 17 Sep, 2018 7 commits
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Anton Blanchard authored
Static branch hints override dynamic branch prediction on recent POWER CPUs. We should only use them when we are overwhelmingly sure of the direction. Signed-off-by:
Anton Blanchard <anton@samba.org> Signed-off-by:
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Laurent Dufour authored
This hypervisor's call allows to remove up to 8 ptes with only call to tlbie. The virtual pages must be all within the same naturally aligned 8 pages virtual address block and have the same page and segment size encodings. Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by:
Laurent Dufour <ldufour@linux.vnet.ibm.com> Signed-off-by:
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Laurent Dufour authored
This part of code will be called also when dealing with H_BLOCK_REMOVE. Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reviewed-by:
Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by:
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Laurent Dufour authored
This feature tells if the hcall H_BLOCK_REMOVE is available. Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reviewed-by:
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Breno Leitao authored
This patch simply fix part of the documentation on the HTM code. This fixes reference to old fields that were renamed in commit 000ec280 ("powerpc: tm: Rename transct_(*) to ck(\1)_state") It also documents better the flow after commit eb5c3f1c ("powerpc: Always save/restore checkpointed regs during treclaim/trecheckpoint"), where tm_recheckpoint can recheckpoint what is in ck{fp,vr}_state blindly. Signed-off-by:
Michael Neuling <mikey@neuling.org> Signed-off-by:
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Breno Leitao authored
Test tm-tmspr might exit before all threads stop executing, because it just waits for the very last thread to join before proceeding/exiting. This patch makes sure that all threads that were created will join before proceeding/exiting. This patch also guarantees that the amount of threads being created is equal to thread_num. Signed-off-by:
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Joel Stanley authored
Deciding wich govenors should be built into the kernel can be left to users to configure. Fixes: 81f35902 ("cpufreq: powernv: Select CPUFreq related Kconfig options for powernv") Signed-off-by:
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- 14 Sep, 2018 2 commits
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Alan Modra authored
Call Frame Information is used by gdb for back-traces and inserting breakpoints on function return for the "finish" command. This failed when inside __kernel_clock_gettime. More concerning than difficulty debugging is that CFI is also used by stack frame unwinding code to implement exceptions. If you have an app that needs to handle asynchronous exceptions for some reason, and you are unlucky enough to get one inside the VDSO time functions, your app will crash. What's wrong: There is control flow in __kernel_clock_gettime that reaches label 99 without saving lr in r12. CFI info however is interpreted by the unwinder without reference to control flow: It's a simple matter of "Execute all the CFI opcodes up to the current address". That means the unwinder thinks r12 contains the return address at label 99. Disabuse it of that notion by resetting CFI for the return address at label 99. Note that the ".cfi_restore lr" could have gone anywhere from the "mtlr r12" a few instructions earlier to the instruction at label 99. I put the CFI as late as possible, because in general that's best practice (and if possible grouped with other CFI in order to reduce the number of CFI opcodes executed when unwinding). Using r12 as the return address is perfectly fine after the "mtlr r12" since r12 on that code path still contains the return address. __get_datapage also has a CFI error. That function temporarily saves lr in r0, and reflects that fact with ".cfi_register lr,r0". A later use of r0 means the CFI at that point isn't correct, as r0 no longer contains the return address. Fix that too. Signed-off-by:
Alan Modra <amodra@gmail.com> Tested-by:
Reza Arbab <arbab@linux.ibm.com> Signed-off-by:
Paul Mackerras <paulus@ozlabs.org>
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Michael Neuling authored
Currently on P9N DD2.1 we end up taking infinite TM facility unavailable exceptions on the first TM usage by userspace. In the special case of TM no suspend (P9N DD2.1), Linux is told TM is off via CPU dt-ftrs but told to (partially) use it via OPAL_REINIT_CPUS_TM_SUSPEND_DISABLED. So HFSCR[TM] will be off from dt-ftrs but we need to turn it on for the no suspend case. This patch fixes this by enabling HFSCR TM in this case. Cc: stable@vger.kernel.org # 4.15+ Signed-off-by:
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- 10 Sep, 2018 1 commit
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Linus Torvalds authored
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- 09 Sep, 2018 5 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull x86 fixes from Thomas Gleixner: "A set of fixes for x86: - Prevent multiplication result truncation on 32bit. Introduced with the early timestamp reworrk. - Ensure microcode revision storage to be consistent under all circumstances - Prevent write tearing of PTEs - Prevent confusion of user and kernel reegisters when dumping fatal signals verbosely - Make an error return value in a failure path of the vector allocation negative. Returning EINVAL might the caller assume success and causes further wreckage. - A trivial kernel doc warning fix" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm: Use WRITE_ONCE() when setting PTEs x86/apic/vector: Make error return value negative x86/process: Don't mix user/kernel regs in 64bit __show_regs() x86/tsc: Prevent result truncation on 32bit x86: Fix kernel-doc atomic.h warnings x86/microcode: Update the new microcode revision unconditionally x86/microcode: Make sure boot_cpu_data.microcode is up-to-date -
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull timekeeping fixes from Thomas Gleixner: "Two fixes for timekeeping: - Revert to the previous kthread based update, which is unfortunately required due to lock ordering issues. The removal caused boot failures on old Core2 machines. Add a proper comment why the thread needs to stay to prevent accidental removal in the future. - Fix a silly typo in a function declaration" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: clocksource: Revert "Remove kthread" timekeeping: Fix declaration of read_persistent_wall_and_boot_offset() -
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull irqchip fix from Thomas Gleixner: "A single fix to prevent allocating excessive memory in the GIC/ITS driver. While the subject of the patch might suggest otherwise this is a real fix as some SoCs exceed the memory allocation limits and fail to boot" * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: irqchip/gic-v3-its: Cap lpi_id_bits to reduce memory footprint
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull cpu hotplug fixes from Thomas Gleixner: "Two fixes for the hotplug state machine code: - Move the misplaces smb() in the hotplug thread function to the proper place, otherwise a half update control struct could be observed - Prevent state corruption on error rollback, which causes the state to advance by one and as a consequence skip it in the bringup sequence" * 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: cpu/hotplug: Prevent state corruption on error rollback cpu/hotplug: Adjust misplaced smb() in cpuhp_thread_fun() -
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/randomLinus Torvalds authored
Pull random driver fix from Ted Ts'o: "Fix things so the choice of whether or not to trust RDRAND to initialize the CRNG is configurable via the boot option random.trust_cpu={on,off}" * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random: random: make CPU trust a boot parameter
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