kernel/arch/x86/include, branch linux-5.1.y

Revert "kvm: x86: Use task structs fpu field for user"

2019-07-28T06:28:38Z

commit ec269475cba7bcdd1eb8fdf8e87f4c6c81a376fe upstream. This reverts commit 240c35a3783ab9b3a0afaba0dde7291295680a6b ("kvm: x86: Use task structs fpu field for user", 2018-11-06). The commit is broken and causes QEMU's FPU state to be destroyed when KVM_RUN is preempted. Fixes: 240c35a3783a ("kvm: x86: Use task structs fpu field for user") Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

x86/atomic: Fix smp_mb__{before,after}_atomic()

2019-07-26T07:12:36Z

[ Upstream commit 69d927bba39517d0980462efc051875b7f4db185 ] Recent probing at the Linux Kernel Memory Model uncovered a 'surprise'. Strongly ordered architectures where the atomic RmW primitive implies full memory ordering and smp_mb__{before,after}_atomic() are a simple barrier() (such as x86) fail for: *x = 1; atomic_inc(u); smp_mb__after_atomic(); r0 = *y; Because, while the atomic_inc() implies memory order, it (surprisingly) does not provide a compiler barrier. This then allows the compiler to re-order like so: atomic_inc(u); *x = 1; smp_mb__after_atomic(); r0 = *y; Which the CPU is then allowed to re-order (under TSO rules) like: atomic_inc(u); r0 = *y; *x = 1; And this very much was not intended. Therefore strengthen the atomic RmW ops to include a compiler barrier. NOTE: atomic_{or,and,xor} and the bitops already had the compiler barrier. Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin

x86/cpufeatures: Add FDP_EXCPTN_ONLY and ZERO_FCS_FDS

2019-07-26T07:12:35Z

[ Upstream commit cbb99c0f588737ec98c333558922ce47e9a95827 ] Add the CPUID enumeration for Intel's de-feature bits to accommodate passing these de-features through to kvm guests. These de-features are (from SDM vol 1, section 8.1.8): - X86_FEATURE_FDP_EXCPTN_ONLY: If CPUID.(EAX=07H,ECX=0H):EBX[bit 6] = 1, the data pointer (FDP) is updated only for the x87 non-control instructions that incur unmasked x87 exceptions. - X86_FEATURE_ZERO_FCS_FDS: If CPUID.(EAX=07H,ECX=0H):EBX[bit 13] = 1, the processor deprecates FCS and FDS; it saves each as 0000H. Signed-off-by: Aaron Lewis Signed-off-by: Borislav Petkov Reviewed-by: Jim Mattson Cc: Fenghua Yu Cc: Frederic Weisbecker Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Konrad Rzeszutek Wilk Cc: marcorr@google.com Cc: Peter Feiner Cc: pshier@google.com Cc: Robert Hoo Cc: Thomas Gleixner Cc: Thomas Lendacky Cc: x86-ml Link: https://lkml.kernel.org/r/20190605220252.103406-1-aaronlewis@google.com Signed-off-by: Sasha Levin

x86/cpu: Add Ice Lake NNPI to Intel family

2019-07-26T07:12:35Z

[ Upstream commit e32d045cd4ba06b59878323e434bad010e78e658 ] Add the CPUID model number of Ice Lake Neural Network Processor for Deep Learning Inference (ICL-NNPI) to the Intel family list. Ice Lake NNPI uses model number 0x9D and this will be documented in a future version of Intel Software Development Manual. Signed-off-by: Rajneesh Bhardwaj Signed-off-by: Thomas Gleixner Cc: bp@suse.de Cc: Borislav Petkov Cc: Dave Hansen Cc: Andy Shevchenko Cc: "H. Peter Anvin" Cc: Kan Liang Cc: Peter Zijlstra Cc: platform-driver-x86@vger.kernel.org Cc: Qiuxu Zhuo Cc: Srinivas Pandruvada Cc: Len Brown Cc: Linux PM Link: https://lkml.kernel.org/r/20190606012419.13250-1-rajneesh.bhardwaj@linux.intel.com Signed-off-by: Sasha Levin

x86/irq: Seperate unused system vectors from spurious entry again

2019-07-21T07:02:02Z

commit f8a8fe61fec8006575699559ead88b0b833d5cad upstream. Quite some time ago the interrupt entry stubs for unused vectors in the system vector range got removed and directly mapped to the spurious interrupt vector entry point. Sounds reasonable, but it's subtly broken. The spurious interrupt vector entry point pushes vector number 0xFF on the stack which makes the whole logic in __smp_spurious_interrupt() pointless. As a consequence any spurious interrupt which comes from a vector != 0xFF is treated as a real spurious interrupt (vector 0xFF) and not acknowledged. That subsequently stalls all interrupt vectors of equal and lower priority, which brings the system to a grinding halt. This can happen because even on 64-bit the system vector space is not guaranteed to be fully populated. A full compile time handling of the unused vectors is not possible because quite some of them are conditonally populated at runtime. Bring the entry stubs back, which wastes 160 bytes if all stubs are unused, but gains the proper handling back. There is no point to selectively spare some of the stubs which are known at compile time as the required code in the IDT management would be way larger and convoluted. Do not route the spurious entries through common_interrupt and do_IRQ() as the original code did. Route it to smp_spurious_interrupt() which evaluates the vector number and acts accordingly now that the real vector numbers are handed in. Fixup the pr_warn so the actual spurious vector (0xff) is clearly distiguished from the other vectors and also note for the vectored case whether it was pending in the ISR or not. "Spurious APIC interrupt (vector 0xFF) on CPU#0, should never happen." "Spurious interrupt vector 0xed on CPU#1. Acked." "Spurious interrupt vector 0xee on CPU#1. Not pending!." Fixes: 2414e021ac8d ("x86: Avoid building unused IRQ entry stubs") Reported-by: Jan Kiszka Signed-off-by: Thomas Gleixner Cc: Marc Zyngier Cc: Jan Beulich Link: https://lkml.kernel.org/r/20190628111440.550568228@linutronix.de Signed-off-by: Greg Kroah-Hartman

x86/irq: Handle spurious interrupt after shutdown gracefully

2019-07-21T07:02:02Z

commit b7107a67f0d125459fe41f86e8079afd1a5e0b15 upstream. Since the rework of the vector management, warnings about spurious interrupts have been reported. Robert provided some more information and did an initial analysis. The following situation leads to these warnings: CPU 0 CPU 1 IO_APIC interrupt is raised sent to CPU1 Unable to handle immediately (interrupts off, deep idle delay) mask() ... free() shutdown() synchronize_irq() clear_vector() do_IRQ() -> vector is clear Before the rework the vector entries of legacy interrupts were statically assigned and occupied precious vector space while most of them were unused. Due to that the above situation was handled silently because the vector was handled and the core handler of the assigned interrupt descriptor noticed that it is shut down and returned. While this has been usually observed with legacy interrupts, this situation is not limited to them. Any other interrupt source, e.g. MSI, can cause the same issue. After adding proper synchronization for level triggered interrupts, this can only happen for edge triggered interrupts where the IO-APIC obviously cannot provide information about interrupts in flight. While the spurious warning is actually harmless in this case it worries users and driver developers. Handle it gracefully by marking the vector entry as VECTOR_SHUTDOWN instead of VECTOR_UNUSED when the vector is freed up. If that above late handling happens the spurious detector will not complain and switch the entry to VECTOR_UNUSED. Any subsequent spurious interrupt on that line will trigger the spurious warning as before. Fixes: 464d12309e1b ("x86/vector: Switch IOAPIC to global reservation mode") Reported-by: Robert Hodaszi Signed-off-by: Thomas Gleixner - Tested-by: Robert Hodaszi Cc: Marc Zyngier Link: https://lkml.kernel.org/r/20190628111440.459647741@linutronix.de Signed-off-by: Greg Kroah-Hartman

x86/CPU: Add more Icelake model numbers

2019-07-10T07:52:24Z

[ Upstream commit e35faeb64146f2015f2aec14b358ae508e4066db ] Add the CPUID model numbers of Icelake (ICL) desktop and server processors to the Intel family list. [ Qiuxu: Sort the macros by model number. ] Signed-off-by: Kan Liang Signed-off-by: Borislav Petkov Cc: "H. Peter Anvin" Cc: Andy Shevchenko Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Qiuxu Zhuo Cc: Rajneesh Bhardwaj Cc: rui.zhang@intel.com Cc: Thomas Gleixner Cc: Tony Luck Cc: x86-ml Link: https://lkml.kernel.org/r/20190603134122.13853-1-kan.liang@linux.intel.com Signed-off-by: Sasha Levin

x86/uaccess: Dont leak the AC flag into __put_user() argument evaluation

2019-05-31T13:43:25Z

[ Upstream commit 6ae865615fc43d014da2fd1f1bba7e81ee622d1b ] The __put_user() macro evaluates it's @ptr argument inside the __uaccess_begin() / __uaccess_end() region. While this would normally not be expected to be an issue, an UBSAN bug (it ignored -fwrapv, fixed in GCC 8+) would transform the @ptr evaluation for: drivers/gpu/drm/i915/i915_gem_execbuffer.c: if (unlikely(__put_user(offset, &urelocs[r-stack].presumed_offset))) { into a signed-overflow-UB check and trigger the objtool AC validation. Finish this commit: 2a418cf3f5f1 ("x86/uaccess: Don't leak the AC flag into __put_user() value evaluation") and explicitly evaluate all 3 arguments early. Reported-by: Randy Dunlap Signed-off-by: Peter Zijlstra (Intel) Acked-by: Randy Dunlap # build-tested Acked-by: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: luto@kernel.org Fixes: 2a418cf3f5f1 ("x86/uaccess: Don't leak the AC flag into __put_user() value evaluation") Link: http://lkml.kernel.org/r/20190424072208.695962771@infradead.org Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin

x86: Hide the int3_emulate_call/jmp functions from UML

2019-05-31T13:43:08Z

commit 693713cbdb3a4bda5a8a678c31f06560bbb14657 upstream. User Mode Linux does not have access to the ip or sp fields of the pt_regs, and accessing them causes UML to fail to build. Hide the int3_emulate_jmp() and int3_emulate_call() instructions from UML, as it doesn't need them anyway. Reported-by: kbuild test robot Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

x86/mpx, mm/core: Fix recursive munmap() corruption

2019-05-25T16:16:40Z

commit 5a28fc94c9143db766d1ba5480cae82d856ad080 upstream. This is a bit of a mess, to put it mildly. But, it's a bug that only seems to have showed up in 4.20 but wasn't noticed until now, because nobody uses MPX. MPX has the arch_unmap() hook inside of munmap() because MPX uses bounds tables that protect other areas of memory. When memory is unmapped, there is also a need to unmap the MPX bounds tables. Barring this, unused bounds tables can eat 80% of the address space. But, the recursive do_munmap() that gets called vi arch_unmap() wreaks havoc with __do_munmap()'s state. It can result in freeing populated page tables, accessing bogus VMA state, double-freed VMAs and more. See the "long story" further below for the gory details. To fix this, call arch_unmap() before __do_unmap() has a chance to do anything meaningful. Also, remove the 'vma' argument and force the MPX code to do its own, independent VMA lookup. == UML / unicore32 impact == Remove unused 'vma' argument to arch_unmap(). No functional change. I compile tested this on UML but not unicore32. == powerpc impact == powerpc uses arch_unmap() well to watch for munmap() on the VDSO and zeroes out 'current->mm->context.vdso_base'. Moving arch_unmap() makes this happen earlier in __do_munmap(). But, 'vdso_base' seems to only be used in perf and in the signal delivery that happens near the return to userspace. I can not find any likely impact to powerpc, other than the zeroing happening a little earlier. powerpc does not use the 'vma' argument and is unaffected by its removal. I compile-tested a 64-bit powerpc defconfig. == x86 impact == For the common success case this is functionally identical to what was there before. For the munmap() failure case, it's possible that some MPX tables will be zapped for memory that continues to be in use. But, this is an extraordinarily unlikely scenario and the harm would be that MPX provides no protection since the bounds table got reset (zeroed). I can't imagine anyone doing this: ptr = mmap(); // use ptr ret = munmap(ptr); if (ret) // oh, there was an error, I'll // keep using ptr. Because if you're doing munmap(), you are *done* with the memory. There's probably no good data in there _anyway_. This passes the original reproducer from Richard Biener as well as the existing mpx selftests/. The long story: munmap() has a couple of pieces: 1. Find the affected VMA(s) 2. Split the start/end one(s) if neceesary 3. Pull the VMAs out of the rbtree 4. Actually zap the memory via unmap_region(), including freeing page tables (or queueing them to be freed). 5. Fix up some of the accounting (like fput()) and actually free the VMA itself. This specific ordering was actually introduced by: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") during the 4.20 merge window. The previous __do_munmap() code was actually safe because the only thing after arch_unmap() was remove_vma_list(). arch_unmap() could not see 'vma' in the rbtree because it was detached, so it is not even capable of doing operations unsafe for remove_vma_list()'s use of 'vma'. Richard Biener reported a test that shows this in dmesg: [1216548.787498] BUG: Bad rss-counter state mm:0000000017ce560b idx:1 val:551 [1216548.787500] BUG: non-zero pgtables_bytes on freeing mm: 24576 What triggered this was the recursive do_munmap() called via arch_unmap(). It was freeing page tables that has not been properly zapped. But, the problem was bigger than this. For one, arch_unmap() can free VMAs. But, the calling __do_munmap() has variables that *point* to VMAs and obviously can't handle them just getting freed while the pointer is still in use. I tried a couple of things here. First, I tried to fix the page table freeing problem in isolation, but I then found the VMA issue. I also tried having the MPX code return a flag if it modified the rbtree which would force __do_munmap() to re-walk to restart. That spiralled out of control in complexity pretty fast. Just moving arch_unmap() and accepting that the bonkers failure case might eat some bounds tables seems like the simplest viable fix. This was also reported in the following kernel bugzilla entry: https://bugzilla.kernel.org/show_bug.cgi?id=203123 There are some reports that this commit triggered this bug: dd2283f2605 ("mm: mmap: zap pages with read mmap_sem in munmap") While that commit certainly made the issues easier to hit, I believe the fundamental issue has been with us as long as MPX itself, thus the Fixes: tag below is for one of the original MPX commits. [ mingo: Minor edits to the changelog and the patch. ] Reported-by: Richard Biener Reported-by: H.J. Lu Signed-off-by: Dave Hansen Reviewed-by Thomas Gleixner Reviewed-by: Yang Shi Acked-by: Michael Ellerman Cc: Andrew Morton Cc: Andy Lutomirski Cc: Anton Ivanov Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Guan Xuetao Cc: H. Peter Anvin Cc: Jeff Dike Cc: Linus Torvalds Cc: Michal Hocko Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Richard Weinberger Cc: Rik van Riel Cc: Vlastimil Babka Cc: linux-arch@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-um@lists.infradead.org Cc: linuxppc-dev@lists.ozlabs.org Cc: stable@vger.kernel.org Fixes: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") Link: http://lkml.kernel.org/r/20190419194747.5E1AD6DC@viggo.jf.intel.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman