- 21 Feb, 2018 6 commits
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Peter Zijlstra authored
David requested a objtool validation pass for CONFIG_RETPOLINE=y enabled builds, where it validates no unannotated indirect jumps or calls are left. Add an additional .discard.retpoline_safe section to allow annotating the few indirect sites that are required and safe. Requested-by:
David Woodhouse <dwmw2@infradead.org> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
David Woodhouse <dwmw@amazon.co.uk> Acked-by:
Thomas Gleixner <tglx@linutronix.de> Acked-by:
Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Peter Zijlstra authored
Use the existing global variables instead of passing them around and creating duplicate global variables. Signed-off-by:
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Peter Zijlstra authored
This is boot code and thus Spectre-safe: we run this _way_ before userspace comes along to have a chance to poison our branch predictor. Signed-off-by:
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Peter Zijlstra authored
The objtool retpoline validation found this indirect jump. Seeing how it's on CPU bringup before we run userspace it should be safe, annotate it. Signed-off-by:
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Peter Zijlstra authored
Paravirt emits indirect calls which get flagged by objtool retpoline checks, annotate it away because all these indirect calls will be patched out before we start userspace. This patching happens through alternative_instructions() -> apply_paravirt() -> pv_init_ops.patch() which will eventually end up in paravirt_patch_default(). This function _will_ write direct alternatives. Signed-off-by:
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Peter Zijlstra authored
Annotate the indirect calls/jumps in the CALL_NOSPEC/JUMP_NOSPEC alternatives. Signed-off-by:
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- 20 Feb, 2018 9 commits
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David Woodhouse authored
Signed-off-by:
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David Woodhouse authored
Retpoline means the kernel is safe because it has no indirect branches. But firmware isn't, so use IBRS for firmware calls if it's available. Block preemption while IBRS is set, although in practice the call sites already had to be doing that. Ignore hpwdt.c for now. It's taking spinlocks and calling into firmware code, from an NMI handler. I don't want to touch that with a bargepole. Signed-off-by:
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David Woodhouse authored
This reverts commit 1dde7415. By putting the RSB filling out of line and calling it, we waste one RSB slot for returning from the function itself, which means one fewer actual function call we can make if we're doing the Skylake abomination of call-depth counting. It also changed the number of RSB stuffings we do on vmexit from 32, which was correct, to 16. Let's just stop with the bikeshedding; it didn't actually *fix* anything anyway. Signed-off-by:
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Jan Beulich authored
Omitting suffixes from instructions in AT&T mode is bad practice when operand size cannot be determined by the assembler from register operands, and is likely going to be warned about by upstream GAS in the future (mine does already). Add the single missing suffix here. Signed-off-by:
Jan Beulich <jbeulich@suse.com> Acked-by:
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Jan Beulich authored
BUG() doesn't always imply "no return", and hence should be followed by a return statement even if that's obviously (to a human) unreachable. Signed-off-by:
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Jan Beulich authored
Constants wider than 32 bits should be tagged with ULL. Signed-off-by:
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Jan Beulich authored
Commit: df340524 ("x86/asm: Add suffix macro for GEN_*_RMWcc()") ... introduced "suffix" RMWcc operations, adding bogus clobber specifiers: For one, on x86 there's no point explicitly clobbering "cc". In fact, with GCC properly fixed, this results in an overlap being detected by the compiler between outputs and clobbers. Furthermore it seems bad practice to me to have clobber specification and use of the clobbered register(s) disconnected - it should rather be at the invocation place of that GEN_{UN,BIN}ARY_SUFFIXED_RMWcc() macros that the clobber is specified which this particular invocation needs. Drop the "cc" clobber altogether and move the "cx" one to refcount.h. Signed-off-by:
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Jann Horn authored
This comment referred to a conditional call to kmemcheck_hide() that was here until commit 49502766 ("kmemcheck: remove annotations"). Now that kmemcheck has been removed, it doesn't make sense anymore. Signed-off-by:
Jann Horn <jannh@google.com> Acked-by:
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Jan Beulich authored
Just like pte_{set,clear}_flags() their PMD and PUD counterparts should not do any address translation. This was outright wrong under Xen (causing a dead boot with no useful output on "suitable" systems), and produced needlessly more complicated code (even if just slightly) when paravirt was enabled. Signed-off-by:Juergen Gross <jgross@suse.com> Acked-by:
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- 17 Feb, 2018 8 commits
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Dominik Brodowski authored
On some x86 CPU microarchitectures using 'xorq' to clear general-purpose registers is slower than 'xorl'. As 'xorl' is sufficient to clear all 64 bits of these registers due to zero-extension [*], switch the x86 64-bit entry code to use 'xorl'. No change in functionality and no change in code size. [*] According to Intel 64 and IA-32 Architecture Software Developer's Manual, section 3.4.1.1, the result of 32-bit operands are "zero- extended to a 64-bit result in the destination general-purpose register." The AMD64 Architecture Programmer’s Manual Volume 3, Appendix B.1, describes the same behaviour. Suggested-by:Denys Vlasenko <dvlasenk@redhat.com> Signed-off-by:
Dominik Brodowski <linux@dominikbrodowski.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180214175924.23065-3-linux@dominikbrodowski.net [ Improved on the changelog a bit. ] Signed-off-by:
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Dominik Brodowski authored
Play a little trick in the generic PUSH_AND_CLEAR_REGS macro to insert the GP registers "above" the original return address. This allows us to (re-)insert the macro in error_entry() and paranoid_entry() and to remove it from the idtentry macro. This reduces the static footprint significantly: text data bss dec hex filename 24307 0 0 24307 5ef3 entry_64.o-orig 20987 0 0 20987 51fb entry_64.o Co-developed-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
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Borislav Petkov authored
With some microcode upgrades, new CPUID features can become visible on the CPU. Check what the kernel has mirrored now and issue a warning hinting at possible things the user/admin can do to make use of the newly visible features. Originally-by:
Ashok Raj <ashok.raj@intel.com> Tested-by:
Borislav Petkov <bp@suse.de> Reviewed-by:
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Borislav Petkov authored
Add a callback function which the microcode loader calls when microcode has been updated to a newer revision. Do the callback only when no error was encountered during loading. Tested-by:
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Borislav Petkov authored
... so that callers can know when microcode was updated and act accordingly. Tested-by:
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Dan Williams authored
The nospec.h header expects the per-architecture header file <asm/barrier.h> to optionally define array_index_mask_nospec(). Include that dependency to prevent inadvertent fallback to the default array_index_mask_nospec() implementation. The default implementation may not provide a full mitigation on architectures that perform data value speculation. Reported-by:
Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by:
Dan Williams <dan.j.williams@intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arch@vger.kernel.org Link: http://lkml.kernel.org/r/151881605404.17395.1341935530792574707.stgit@dwillia2-desk3.amr.corp.intel.comSigned-off-by:
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Rasmus Villemoes authored
The last expression in a statement expression need not be a bare variable, quoting gcc docs The last thing in the compound statement should be an expression followed by a semicolon; the value of this subexpression serves as the value of the entire construct. and we already use that in e.g. the min/max macros which end with a ternary expression. This way, we can allow index to have const-qualified type, which will in some cases avoid the need for introducing a local copy of index of non-const qualified type. That, in turn, can prevent readers not familiar with the internals of array_index_nospec from wondering about the seemingly redundant extra variable, and I think that's worthwhile considering how confusing the whole _nospec business is. The expression _i&_mask has type unsigned long (since that is the type of _mask, and the BUILD_BUG_ONs guarantee that _i will get promoted to that), so in order not to change the type of the whole expression, add a cast back to typeof(_i). Signed-off-by:
Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by:
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Dan Williams authored
There are multiple problems with the dynamic sanity checking in array_index_nospec_mask_check(): * It causes unnecessary overhead in the 32-bit case since integer sized @index values will no longer cause the check to be compiled away like in the 64-bit case. * In the 32-bit case it may trigger with user controllable input when the expectation is that should only trigger during development of new kernel enabling. * The macro reuses the input parameter in multiple locations which is broken if someone passes an expression like 'index++' to array_index_nospec(). Reported-by:
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- 15 Feb, 2018 15 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull x86 PTI and Spectre related fixes and updates from Ingo Molnar: "Here's the latest set of Spectre and PTI related fixes and updates: Spectre: - Add entry code register clearing to reduce the Spectre attack surface - Update the Spectre microcode blacklist - Inline the KVM Spectre helpers to get close to v4.14 performance again. - Fix indirect_branch_prediction_barrier() - Fix/improve Spectre related kernel messages - Fix array_index_nospec_mask() asm constraint - KVM: fix two MSR handling bugs PTI: - Fix a paranoid entry PTI CR3 handling bug - Fix comments objtool: - Fix paranoid_entry() frame pointer warning - Annotate WARN()-related UD2 as reachable - Various fixes - Add Add Peter Zijlstra as objtool co-maintainer Misc: - Various x86 entry code self-test fixes - Improve/simplify entry code stack frame generation and handling after recent heavy-handed PTI and Spectre changes. (There's two more WIP improvements expected here.) - Type fix for cache entries There's also some low risk non-fix changes I've included in this branch to reduce backporting conflicts: - rename a confusing x86_cpu field name - de-obfuscate the naming of single-TLB flushing primitives" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits) x86/entry/64: Fix CR3 restore in paranoid_exit() x86/cpu: Change type of x86_cache_size variable to unsigned int x86/spectre: Fix an error message x86/cpu: Rename cpu_data.x86_mask to cpu_data.x86_stepping selftests/x86/mpx: Fix incorrect bounds with old _sigfault x86/mm: Rename flush_tlb_single() and flush_tlb_one() to __flush_tlb_one_[user|kernel]() x86/speculation: Add <asm/msr-index.h> dependency nospec: Move array_index_nospec() parameter checking into separate macro x86/speculation: Fix up array_index_nospec_mask() asm constraint x86/debug: Use UD2 for WARN() x86/debug, objtool: Annotate WARN()-related UD2 as reachable objtool: Fix segfault in ignore_unreachable_insn() selftests/x86: Disable tests requiring 32-bit support on pure 64-bit systems selftests/x86: Do not rely on "int $0x80" in single_step_syscall.c selftests/x86: Do not rely on "int $0x80" in test_mremap_vdso.c selftests/x86: Fix build bug caused by the 5lvl test which has been moved to the VM directory selftests/x86/pkeys: Remove unused functions selftests/x86: Clean up and document sscanf() usage selftests/x86: Fix vDSO selftest segfault for vsyscall=none x86/entry/64: Remove the unused 'icebp' macro ... -
Ingo Molnar authored
Josh Poimboeuf noticed the following bug: "The paranoid exit code only restores the saved CR3 when it switches back to the user GS. However, even in the kernel GS case, it's possible that it needs to restore a user CR3, if for example, the paranoid exception occurred in the syscall exit path between SWITCH_TO_USER_CR3_STACK and SWAPGS." Josh also confirmed via targeted testing that it's possible to hit this bug. Fix the bug by also restoring CR3 in the paranoid_exit_no_swapgs branch. The reason we haven't seen this bug reported by users yet is probably because "paranoid" entry points are limited to the following cases: idtentry double_fault do_double_fault has_error_code=1 paranoid=2 idtentry debug do_debug has_error_code=0 paranoid=1 shift_ist=DEBUG_STACK idtentry int3 do_int3 has_error_code=0 paranoid=1 shift_ist=DEBUG_STACK idtentry machine_check do_mce has_error_code=0 paranoid=1 Amongst those entry points only machine_check is one that will interrupt an IRQS-off critical section asynchronously - and machine check events are rare. The other main asynchronous entries are NMI entries, which can be very high-freq with perf profiling, but they are special: they don't use the 'idtentry' macro but are open coded and restore user CR3 unconditionally so don't have this bug. Reported-and-tested-by:
Andy Lutomirski <luto@kernel.org> Acked-by:
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Gustavo A. R. Silva authored
Currently, x86_cache_size is of type int, which makes no sense as we will never have a valid cache size equal or less than 0. So instead of initializing this variable to -1, it can perfectly be initialized to 0 and use it as an unsigned variable instead. Suggested-by:
Gustavo A. R. Silva <garsilva@embeddedor.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Addresses-Coverity-ID: 1464429 Link: http://lkml.kernel.org/r/20180213192208.GA26414@embeddedor.comSigned-off-by:
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Dan Carpenter authored
If i == ARRAY_SIZE(mitigation_options) then we accidentally print garbage from one space beyond the end of the mitigation_options[] array. Signed-off-by:
Dan Carpenter <dan.carpenter@oracle.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@suse.de> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: KarimAllah Ahmed <karahmed@amazon.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kernel-janitors@vger.kernel.org Fixes: 9005c683 ("x86/spectre: Simplify spectre_v2 command line parsing") Link: http://lkml.kernel.org/r/20180214071416.GA26677@mwandaSigned-off-by:
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Jia Zhang authored
x86_mask is a confusing name which is hard to associate with the processor's stepping. Additionally, correct an indent issue in lib/cpu.c. Signed-off-by:
Jia Zhang <qianyue.zj@alibaba-inc.com> [ Updated it to more recent kernels. ] Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: bp@alien8.de Cc: tony.luck@intel.com Link: http://lkml.kernel.org/r/1514771530-70829-1-git-send-email-qianyue.zj@alibaba-inc.comSigned-off-by:
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Rui Wang authored
For distributions with old userspace header files, the _sigfault structure is different. mpx-mini-test fails with the following error: [root@Purley]# mpx-mini-test_64 tabletest XSAVE is supported by HW & OS XSAVE processor supported state mask: 0x2ff XSAVE OS supported state mask: 0x2ff BNDREGS: size: 64 user: 1 supervisor: 0 aligned: 0 BNDCSR: size: 64 user: 1 supervisor: 0 aligned: 0 starting mpx bounds table test ERROR: siginfo bounds do not match shadow bounds for register 0 Fix it by using the correct offset of _lower/_upper in _sigfault. RHEL needs this patch to work. Signed-off-by:Rui Wang <rui.y.wang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dave.hansen@linux.intel.com Fixes: e754aedc ("x86/mpx, selftests: Add MPX self test") Link: http://lkml.kernel.org/r/1513586050-1641-1-git-send-email-rui.y.wang@intel.comSigned-off-by:
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Andy Lutomirski authored
flush_tlb_single() and flush_tlb_one() sound almost identical, but they really mean "flush one user translation" and "flush one kernel translation". Rename them to flush_tlb_one_user() and flush_tlb_one_kernel() to make the semantics more obvious. [ I was looking at some PTI-related code, and the flush-one-address code is unnecessarily hard to understand because the names of the helpers are uninformative. This came up during PTI review, but no one got around to doing it. ] Signed-off-by:
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Peter Zijlstra authored
Joe Konno reported a compile failure resulting from using an MSR without inclusion of <asm/msr-index.h>, and while the current code builds fine (by accident) this needs fixing for future patches. Reported-by:
Joe Konno <joe.konno@linux.intel.com> Signed-off-by:
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Will Deacon authored
For architectures providing their own implementation of array_index_mask_nospec() in asm/barrier.h, attempting to use WARN_ONCE() to complain about out-of-range parameters using WARN_ON() results in a mess of mutually-dependent include files. Rather than unpick the dependencies, simply have the core code in nospec.h perform the checking for us. Signed-off-by:
Will Deacon <will.deacon@arm.com> Acked-by:
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Dan Williams authored
Allow the compiler to handle @size as an immediate value or memory directly rather than allocating a register. Reported-by:
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Peter Zijlstra authored
Since the Intel SDM added an ModR/M byte to UD0 and binutils followed that specification, we now cannot disassemble our kernel anymore. This now means Intel and AMD disagree on the encoding of UD0. And instead of playing games with additional bytes that are valid ModR/M and single byte instructions (0xd6 for instance), simply use UD2 for both WARN() and BUG(). Requested-by:
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Josh Poimboeuf authored
By default, objtool assumes that a UD2 is a dead end. This is mainly because GCC 7+ sometimes inserts a UD2 when it detects a divide-by-zero condition. Now that WARN() is moving back to UD2, annotate the code after it as reachable so objtool can follow the code flow. Reported-by:
Borislav Petkov <bp@alien8.de> Signed-off-by:
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Josh Poimboeuf authored
Peter Zijlstra's patch for converting WARN() to use UD2 triggered a bunch of false "unreachable instruction" warnings, which then triggered a seg fault in ignore_unreachable_insn(). The seg fault happened when it tried to dereference a NULL 'insn->func' pointer. Thanks to static_cpu_has(), some functions can jump to a non-function area in the .altinstr_aux section. That breaks ignore_unreachable_insn()'s assumption that it's always inside the original function. Make sure ignore_unreachable_insn() only follows jumps within the current function. Reported-by:
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Dominik Brodowski authored
The ldt_gdt and ptrace_syscall selftests, even in their 64-bit variant, use hard-coded 32-bit syscall numbers and call "int $0x80". This will fail on 64-bit systems with CONFIG_IA32_EMULATION=y disabled. Therefore, do not build these tests if we cannot build 32-bit binaries (which should be a good approximation for CONFIG_IA32_EMULATION=y being enabled). Signed-off-by:
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Dominik Brodowski authored
On 64-bit builds, we should not rely on "int $0x80" working (it only does if CONFIG_IA32_EMULATION=y is enabled). To keep the "Set TF and check int80" test running on 64-bit installs with CONFIG_IA32_EMULATION=y enabled, build this test only if we can also build 32-bit binaries (which should be a good approximation for that). Signed-off-by:
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- 14 Feb, 2018 2 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2Linus Torvalds authored
Pull gfs2 fix from Bob Peterson: "Fix regressions in the gfs2 iomap for block_map implementation we recently discovered in commit 3974320c" * tag 'gfs2-4.16.rc1.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2: gfs2: Fixes to "Implement iomap for block_map"
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linuxLinus Torvalds authored
Pull powerpc fixes from Michael Ellerman: "A larger batch of fixes than we'd like. Roughly 1/3 fixes for new code, 1/3 fixes for stable and 1/3 minor things. There's four commits fixing bugs when using 16GB huge pages on hash, caused by some of the preparatory changes for pkeys. Two fixes for bugs in the enhanced IRQ soft masking for local_t, one of which broke KVM in some circumstances. Four fixes for Power9. The most bizarre being a bug where futexes stopped working because a NULL pointer dereference didn't trap during early boot (it aliased the kernel mapping). A fix for memory hotplug when using the Radix MMU, and a fix for live migration of guests using the Radix MMU. Two fixes for hotplug on pseries machines. One where we weren't correctly updating NUMA info when CPUs are added and removed. And the other fixes crashes/hangs seen when doing memory hot remove during boot, which is apparently a thing people do. Finally a handful of build fixes for obscure configs and other minor fixes. Thanks to: Alexey Kardashevskiy, Aneesh Kumar K.V, Balbir Singh, Colin Ian King, Daniel Henrique Barboza, Florian Weimer, Guenter Roeck, Harish, Laurent Vivier, Madhavan Srinivasan, Mauricio Faria de Oliveira, Nathan Fontenot, Nicholas Piggin, Sam Bobroff" * tag 'powerpc-4.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: selftests/powerpc: Fix to use ucontext_t instead of struct ucontext powerpc/kdump: Fix powernv build break when KEXEC_CORE=n powerpc/pseries: Fix build break for SPLPAR=n and CPU hotplug powerpc/mm/hash64: Zero PGD pages on allocation powerpc/mm/hash64: Store the slot information at the right offset for hugetlb powerpc/mm/hash64: Allocate larger PMD table if hugetlb config is enabled powerpc/mm: Fix crashes with 16G huge pages powerpc/mm: Flush radix process translations when setting MMU type powerpc/vas: Don't set uses_vas for kernel windows powerpc/pseries: Enable RAS hotplug events later powerpc/mm/radix: Split linear mapping on hot-unplug powerpc/64s/radix: Boot-time NULL pointer protection using a guard-PID ocxl: fix signed comparison with less than zero powerpc/64s: Fix may_hard_irq_enable() for PMI soft masking powerpc/64s: Fix MASKABLE_RELON_EXCEPTION_HV_OOL macro powerpc/numa: Invalidate numa_cpu_lookup_table on cpu remove
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