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2020-05-08x86/module: Use text_poke() for late relocationsPeter Zijlstra2-7/+47
Because of late module patching, a livepatch module needs to be able to apply some of its relocations well after it has been loaded. Instead of playing games with module_{dis,en}able_ro(), use existing text poking mechanisms to apply relocations after module loading. So far only x86, s390 and Power have HAVE_LIVEPATCH but only the first two also have STRICT_MODULE_RWX. This will allow removal of the last module_disable_ro() usage in livepatch. The ultimate goal is to completely disallow making executable mappings writable. [ jpoimboe: Split up patches. Use mod state to determine whether memcpy() can be used. Implement text_poke() for UML. ] Cc: x86@kernel.org Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-05-08s390/module: Use s390_kernel_write() for late relocationsPeter Zijlstra1-59/+88
Because of late module patching, a livepatch module needs to be able to apply some of its relocations well after it has been loaded. Instead of playing games with module_{dis,en}able_ro(), use existing text poking mechanisms to apply relocations after module loading. So far only x86, s390 and Power have HAVE_LIVEPATCH but only the first two also have STRICT_MODULE_RWX. This will allow removal of the last module_disable_ro() usage in livepatch. The ultimate goal is to completely disallow making executable mappings writable. [ jpoimboe: Split up patches. Use mod state to determine whether memcpy() can be used. Test and add fixes. ] Cc: linux-s390@vger.kernel.org Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> # s390 Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-05-08s390: Change s390_kernel_write() return type to match memcpy()Josh Poimboeuf2-4/+7
s390_kernel_write()'s function type is almost identical to memcpy(). Change its return type to "void *" so they can be used interchangeably. Cc: linux-s390@vger.kernel.org Cc: heiko.carstens@de.ibm.com Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> # s390 Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-05-08livepatch: Remove .klp.archPeter Zijlstra2-54/+0
After the previous patch, vmlinux-specific KLP relocations are now applied early during KLP module load. This means that .klp.arch sections are no longer needed for *vmlinux-specific* KLP relocations. One might think they're still needed for *module-specific* KLP relocations. If a to-be-patched module is loaded *after* its corresponding KLP module is loaded, any corresponding KLP relocations will be delayed until the to-be-patched module is loaded. If any special sections (.parainstructions, for example) rely on those relocations, their initializations (apply_paravirt) need to be done afterwards. Thus the apparent need for arch_klp_init_object_loaded() and its corresponding .klp.arch sections -- it allows some of the special section initializations to be done at a later time. But... if you look closer, that dependency between the special sections and the module-specific KLP relocations doesn't actually exist in reality. Looking at the contents of the .altinstructions and .parainstructions sections, there's not a realistic scenario in which a KLP module's .altinstructions or .parainstructions section needs to access a symbol in a to-be-patched module. It might need to access a local symbol or even a vmlinux symbol; but not another module's symbol. When a special section needs to reference a local or vmlinux symbol, a normal rela can be used instead of a KLP rela. Since the special section initializations don't actually have any real dependency on module-specific KLP relocations, .klp.arch and arch_klp_init_object_loaded() no longer have a reason to exist. So remove them. As Peter said much more succinctly: So the reason for .klp.arch was that .klp.rela.* stuff would overwrite paravirt instructions. If that happens you're doing it wrong. Those RELAs are core kernel, not module, and thus should've happened in .rela.* sections at patch-module loading time. Reverting this removes the two apply_{paravirt,alternatives}() calls from the late patching path, and means we don't have to worry about them when removing module_disable_ro(). [ jpoimboe: Rewrote patch description. Tweaked klp_init_object_loaded() error path. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-05-06Merge branch 'linus' of ↵Linus Torvalds11-34/+69
git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 Pull crypto fixes from Herbert Xu: "This fixes a potential scheduling latency problem for the algorithms used by WireGuard" * 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: crypto: arch/nhpoly1305 - process in explicit 4k chunks crypto: arch/lib - limit simd usage to 4k chunks
2020-05-01Merge tag 'arm64-fixes' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 fix from Catalin Marinas: "Add -fasynchronous-unwind-tables to the vDSO CFLAGS" * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64: vdso: Add -fasynchronous-unwind-tables to cflags
2020-04-30arm64: vdso: Add -fasynchronous-unwind-tables to cflagsVincenzo Frascino1-1/+1
On arm64 linux gcc uses -fasynchronous-unwind-tables -funwind-tables by default since gcc-8, so now the de facto platform ABI is to allow unwinding from async signal handlers. However on bare metal targets (aarch64-none-elf), and on old gcc, async and sync unwind tables are not enabled by default to avoid runtime memory costs. This means if linux is built with a baremetal toolchain the vdso.so may not have unwind tables which breaks the gcc platform ABI guarantee in userspace. Add -fasynchronous-unwind-tables explicitly to the vgettimeofday.o cflags to address the ABI change. Fixes: 28b1a824a4f4 ("arm64: vdso: Substitute gettimeofday() with C implementation") Cc: Will Deacon <will@kernel.org> Reported-by: Szabolcs Nagy <szabolcs.nagy@arm.com> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2020-04-30crypto: arch/nhpoly1305 - process in explicit 4k chunksJason A. Donenfeld4-4/+4
Rather than chunking via PAGE_SIZE, this commit changes the arch implementations to chunk in explicit 4k parts, so that calculations on maximum acceptable latency don't suddenly become invalid on platforms where PAGE_SIZE isn't 4k, such as arm64. Fixes: 0f961f9f670e ("crypto: x86/nhpoly1305 - add AVX2 accelerated NHPoly1305") Fixes: 012c82388c03 ("crypto: x86/nhpoly1305 - add SSE2 accelerated NHPoly1305") Fixes: a00fa0c88774 ("crypto: arm64/nhpoly1305 - add NEON-accelerated NHPoly1305") Fixes: 16aae3595a9d ("crypto: arm/nhpoly1305 - add NEON-accelerated NHPoly1305") Cc: stable@vger.kernel.org Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Reviewed-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2020-04-30crypto: arch/lib - limit simd usage to 4k chunksJason A. Donenfeld7-30/+65
The initial Zinc patchset, after some mailing list discussion, contained code to ensure that kernel_fpu_enable would not be kept on for more than a 4k chunk, since it disables preemption. The choice of 4k isn't totally scientific, but it's not a bad guess either, and it's what's used in both the x86 poly1305, blake2s, and nhpoly1305 code already (in the form of PAGE_SIZE, which this commit corrects to be explicitly 4k for the former two). Ard did some back of the envelope calculations and found that at 5 cycles/byte (overestimate) on a 1ghz processor (pretty slow), 4k means we have a maximum preemption disabling of 20us, which Sebastian confirmed was probably a good limit. Unfortunately the chunking appears to have been left out of the final patchset that added the glue code. So, this commit adds it back in. Fixes: 84e03fa39fbe ("crypto: x86/chacha - expose SIMD ChaCha routine as library function") Fixes: b3aad5bad26a ("crypto: arm64/chacha - expose arm64 ChaCha routine as library function") Fixes: a44a3430d71b ("crypto: arm/chacha - expose ARM ChaCha routine as library function") Fixes: d7d7b8535662 ("crypto: x86/poly1305 - wire up faster implementations for kernel") Fixes: f569ca164751 ("crypto: arm64/poly1305 - incorporate OpenSSL/CRYPTOGAMS NEON implementation") Fixes: a6b803b3ddc7 ("crypto: arm/poly1305 - incorporate OpenSSL/CRYPTOGAMS NEON implementation") Fixes: ed0356eda153 ("crypto: blake2s - x86_64 SIMD implementation") Cc: Eric Biggers <ebiggers@google.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: stable@vger.kernel.org Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2020-04-29Merge tag 'riscv-for-linus-5.7-rc4' of ↵Linus Torvalds4-13/+16
git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux Pull RISC-V fixes from Palmer Dabbelt: "A handful of fixes. Specifically: - fix linker argument to allow linking with lld - build fix for configurations without a frame pointer - a handful of build fixes related the SBI 0.1 vs 0.2 split - remove STRICT_KERNEL_RWX for !MMU, which isn't useful" * tag 'riscv-for-linus-5.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: riscv: select ARCH_HAS_STRICT_KERNEL_RWX only if MMU riscv: sbi: Fix undefined reference to sbi_shutdown tty: riscv: Using RISCV_SBI_V01 instead of RISCV_SBI riscv: sbi: Correct sbi_shutdown() and sbi_clear_ipi() export riscv: fix vdso build with lld RISC-V: stacktrace: Declare sp_in_global outside ifdef
2020-04-28Merge tag 'cve-2020-11884' from emailed bundleLinus Torvalds2-2/+18
Pull s390 fix from Christian Borntraeger: "Fix a race between page table upgrade and uaccess on s390. This fixes CVE-2020-11884 which allows for a local kernel crash or code execution" * tag 'cve-2020-11884' from emailed bundle: s390/mm: fix page table upgrade vs 2ndary address mode accesses
2020-04-27Merge tag 'hyperv-fixes-signed' of ↵Linus Torvalds2-2/+12
git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux Pull Hyper-V fixes from Wei Liu: - Two patches from Dexuan fixing suspension bugs - Three cleanup patches from Andy and Michael * tag 'hyperv-fixes-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: hyper-v: Remove internal types from UAPI header hyper-v: Use UUID API for exporting the GUID x86/hyperv: Suspend/resume the VP assist page for hibernation Drivers: hv: Move AEOI determination to architecture dependent code Drivers: hv: vmbus: Fix Suspend-to-Idle for Generation-2 VM
2020-04-26Merge tag 's390-5.7-3' of ↵Linus Torvalds6-9/+9
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull s390 fixes from Vasily Gorbik: - Add a few notrace annotations to avoid potential crashes when switching ftrace tracers. - Avoid setting affinity for floating irqs in pci code. - Fix build issue found by kbuild test robot. * tag 's390-5.7-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: s390/protvirt: fix compilation issue s390/pci: do not set affinity for floating irqs s390/ftrace: fix potential crashes when switching tracers
2020-04-26Merge tag 'powerpc-5.7-3' of ↵Linus Torvalds4-2/+7
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull powerpc fixes from Michael Ellerman: - One important fix for a bug in the way we find the cache-line size from the device tree, which was leading to the wrong size being reported to userspace on some platforms. - A fix for 8xx STRICT_KERNEL_RWX which was leaving TLB entries around leading to a window at boot when the strict mapping wasn't enforced. - A fix to enable our KUAP (kernel user access prevention) debugging on PPC32. - A build fix for clang in lib/mpi. Thanks to: Chris Packham, Christophe Leroy, Nathan Chancellor, Qian Cai. * tag 'powerpc-5.7-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: lib/mpi: Fix building for powerpc with clang powerpc/mm: Fix CONFIG_PPC_KUAP_DEBUG on PPC32 powerpc/8xx: Fix STRICT_KERNEL_RWX startup test failure powerpc/setup_64: Set cache-line-size based on cache-block-size
2020-04-25Merge tag 'sched-urgent-2020-04-25' of ↵Linus Torvalds1-14/+33
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar: "Misc fixes: - an uclamp accounting fix - three frequency invariance fixes and a readability improvement" * tag 'sched-urgent-2020-04-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/core: Fix reset-on-fork from RT with uclamp x86, sched: Move check for CPU type to caller function x86, sched: Don't enable static key when starting secondary CPUs x86, sched: Account for CPUs with less than 4 cores in freq. invariance x86, sched: Bail out of frequency invariance if base frequency is unknown
2020-04-25Merge tag 'perf-urgent-2020-04-25' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Ingo Molnar: "Two changes: - fix exit event records - extend x86 PMU driver enumeration to add Intel Jasper Lake CPU support" * tag 'perf-urgent-2020-04-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/core: fix parent pid/tid in task exit events perf/x86/cstate: Add Jasper Lake CPU support
2020-04-25s390/protvirt: fix compilation issueClaudio Imbrenda2-3/+2
The kernel fails to compile with CONFIG_PROTECTED_VIRTUALIZATION_GUEST set but CONFIG_KVM unset. This patch fixes the issue by making the needed variable always available. Link: https://lkml.kernel.org/r/20200423120114.2027410-1-imbrenda@linux.ibm.com Fixes: a0f60f843199 ("s390/protvirt: Add sysfs firmware interface for Ultravisor information") Reported-by: kbuild test robot <lkp@intel.com> Reported-by: Philipp Rudo <prudo@linux.ibm.com> Suggested-by: Philipp Rudo <prudo@linux.ibm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Vasily Gorbik <gor@linux.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2020-04-24Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netLinus Torvalds2-9/+37
Pull networking fixes from David Miller: 1) Fix memory leak in netfilter flowtable, from Roi Dayan. 2) Ref-count leaks in netrom and tipc, from Xiyu Yang. 3) Fix warning when mptcp socket is never accepted before close, from Florian Westphal. 4) Missed locking in ovs_ct_exit(), from Tonghao Zhang. 5) Fix large delays during PTP synchornization in cxgb4, from Rahul Lakkireddy. 6) team_mode_get() can hang, from Taehee Yoo. 7) Need to use kvzalloc() when allocating fw tracer in mlx5 driver, from Niklas Schnelle. 8) Fix handling of bpf XADD on BTF memory, from Jann Horn. 9) Fix BPF_STX/BPF_B encoding in x86 bpf jit, from Luke Nelson. 10) Missing queue memory release in iwlwifi pcie code, from Johannes Berg. 11) Fix NULL deref in macvlan device event, from Taehee Yoo. 12) Initialize lan87xx phy correctly, from Yuiko Oshino. 13) Fix looping between VRF and XFRM lookups, from David Ahern. 14) etf packet scheduler assumes all sockets are full sockets, which is not necessarily true. From Eric Dumazet. 15) Fix mptcp data_fin handling in RX path, from Paolo Abeni. 16) fib_select_default() needs to handle nexthop objects, from David Ahern. 17) Use GFP_ATOMIC under spinlock in mac80211_hwsim, from Wei Yongjun. 18) vxlan and geneve use wrong nlattr array, from Sabrina Dubroca. 19) Correct rx/tx stats in bcmgenet driver, from Doug Berger. 20) BPF_LDX zero-extension is encoded improperly in x86_32 bpf jit, fix from Luke Nelson. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (100 commits) selftests/bpf: Fix a couple of broken test_btf cases tools/runqslower: Ensure own vmlinux.h is picked up first bpf: Make bpf_link_fops static bpftool: Respect the -d option in struct_ops cmd selftests/bpf: Add test for freplace program with expected_attach_type bpf: Propagate expected_attach_type when verifying freplace programs bpf: Fix leak in LINK_UPDATE and enforce empty old_prog_fd bpf, x86_32: Fix logic error in BPF_LDX zero-extension bpf, x86_32: Fix clobbering of dst for BPF_JSET bpf, x86_32: Fix incorrect encoding in BPF_LDX zero-extension bpf: Fix reStructuredText markup net: systemport: suppress warnings on failed Rx SKB allocations net: bcmgenet: suppress warnings on failed Rx SKB allocations macsec: avoid to set wrong mtu mac80211: sta_info: Add lockdep condition for RCU list usage mac80211: populate debugfs only after cfg80211 init net: bcmgenet: correct per TX/RX ring statistics net: meth: remove spurious copyright text net: phy: bcm84881: clear settings on link down chcr: Fix CPU hard lockup ...
2020-04-24bpf, x86_32: Fix logic error in BPF_LDX zero-extensionWang YanQing1-1/+1
When verifier_zext is true, we don't need to emit code for zero-extension. Fixes: 836256bf5f37 ("x32: bpf: eliminate zero extension code-gen") Signed-off-by: Wang YanQing <udknight@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200423050637.GA4029@udknight
2020-04-24bpf, x86_32: Fix clobbering of dst for BPF_JSETLuke Nelson1-4/+18
The current JIT clobbers the destination register for BPF_JSET BPF_X and BPF_K by using "and" and "or" instructions. This is fine when the destination register is a temporary loaded from a register stored on the stack but not otherwise. This patch fixes the problem (for both BPF_K and BPF_X) by always loading the destination register into temporaries since BPF_JSET should not modify the destination register. This bug may not be currently triggerable as BPF_REG_AX is the only register not stored on the stack and the verifier uses it in a limited way. Fixes: 03f5781be2c7b ("bpf, x86_32: add eBPF JIT compiler for ia32") Signed-off-by: Xi Wang <xi.wang@gmail.com> Signed-off-by: Luke Nelson <luke.r.nels@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Wang YanQing <udknight@gmail.com> Link: https://lore.kernel.org/bpf/20200422173630.8351-2-luke.r.nels@gmail.com
2020-04-24bpf, x86_32: Fix incorrect encoding in BPF_LDX zero-extensionLuke Nelson1-1/+3
The current JIT uses the following sequence to zero-extend into the upper 32 bits of the destination register for BPF_LDX BPF_{B,H,W}, when the destination register is not on the stack: EMIT3(0xC7, add_1reg(0xC0, dst_hi), 0); The problem is that C7 /0 encodes a MOV instruction that requires a 4-byte immediate; the current code emits only 1 byte of the immediate. This means that the first 3 bytes of the next instruction will be treated as the rest of the immediate, breaking the stream of instructions. This patch fixes the problem by instead emitting "xor dst_hi,dst_hi" to clear the upper 32 bits. This fixes the problem and is more efficient than using MOV to load a zero immediate. This bug may not be currently triggerable as BPF_REG_AX is the only register not stored on the stack and the verifier uses it in a limited way, and the verifier implements a zero-extension optimization. But the JIT should avoid emitting incorrect encodings regardless. Fixes: 03f5781be2c7b ("bpf, x86_32: add eBPF JIT compiler for ia32") Signed-off-by: Xi Wang <xi.wang@gmail.com> Signed-off-by: Luke Nelson <luke.r.nels@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: H. Peter Anvin (Intel) <hpa@zytor.com> Acked-by: Wang YanQing <udknight@gmail.com> Link: https://lore.kernel.org/bpf/20200422173630.8351-1-luke.r.nels@gmail.com
2020-04-24riscv: select ARCH_HAS_STRICT_KERNEL_RWX only if MMUDamien Le Moal1-1/+1
ARCH_HAS_STRICT_KERNEL_RWX is not useful for NO-MMU systems. Furthermore, has this option leads to very large boot image files on 64bits architectures, do not enable this option to allow supporting no-mmu platforms such as the Kendryte K210 SoC based boards. Fixes: 00cb41d5ad31 ("riscv: add alignment for text, rodata and data sections") Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Anup Patel <anup@brainfault.org> Reviewed-by: Wladimir J. van der Laan <laanwj@gmail.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-24Merge tag 'arm64-fixes' of ↵Linus Torvalds1-3/+6
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 fixes from Catalin Marinas: - Ensure context synchronisation after a write to APIAKey. - Fix bullet list formatting in Documentation/arm64/amu.rst to eliminate doc warnings. * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: Documentation: arm64: fix amu.rst doc warnings arm64: sync kernel APIAKey when installing
2020-04-24Merge tag 'kbuild-fixes-v5.7' of ↵Linus Torvalds23-222/+277
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild fixes from Masahiro Yamada: - fix scripts/config to properly handle ':' in string type CONFIG options - fix unneeded rebuilds of DT schema check rule - git rid of ordering dependency between <linux/vermagic.h> and <linux/module.h> to fix build errors in some network drivers - clean up generated headers of host arch with 'make ARCH=um mrproper' * tag 'kbuild-fixes-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: h8300: ignore vmlinux.lds Documentation: kbuild: fix the section title format um: ensure `make ARCH=um mrproper` removes arch/$(SUBARCH)/include/generated/ arch: split MODULE_ARCH_VERMAGIC definitions out to <asm/vermagic.h> kbuild: fix DT binding schema rule again to avoid needless rebuilds scripts/config: allow colons in option strings for sed
2020-04-23Merge tag 'armsoc-fixes' of ↵Linus Torvalds4-0/+11
git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc Pull ARM SoC fixes from Arnd Bergmann: "A few smaller fixes for v5.7-rc3: The majority are fixes for bugs I found after restarting my randconfig build testing that had been dormant for a while. On the Nokia N950/N9 phone, a DT fix is required to address a boot regression. For the bcm283x (Raspberry Pi), two DT fixes address minor issues" * tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: soc: imx8: select SOC_BUS soc: tegra: fix tegra_pmc_get_suspend_mode definition soc: fsl: dpio: avoid stack usage warning soc: fsl: dpio: fix incorrect pointer conversions ARM: imx: provide v7_cpu_resume() only on ARM_CPU_SUSPEND=y ARM: dts: bcm283x: Disable dsi0 node firmware: xilinx: make firmware_debugfs_root static drivers: soc: xilinx: fix firmware driver Kconfig dependency ARM: dts: bcm283x: Add cells encoding format to firmware bus ARM: dts: OMAP3: disable RNG on N950/N9
2020-04-23Merge tag 'arm-soc/for-5.7/devicetree-fixes' of ↵Arnd Bergmann2-0/+4
https://github.com/Broadcom/stblinux into arm/fixes This pull request contains Broadcom ARM-based SoCs Device Tree fixes for 5.7, please pull the following: - Nicolas provides a fix for 55c7c0621078 ("ARM: dts: bcm283x: Fix vc4's firmware bus DMA limitations") which missed adding proper #address-cells and #size-cells properties and he also disables the DSI node which should have been disabled by default but was not. * tag 'arm-soc/for-5.7/devicetree-fixes' of https://github.com/Broadcom/stblinux: ARM: dts: bcm283x: Disable dsi0 node ARM: dts: bcm283x: Add cells encoding format to firmware bus Link: https://lore.kernel.org/r/20200417171725.1084-1-f.fainelli@gmail.com Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2020-04-23h8300: ignore vmlinux.ldsMasahiro Yamada1-0/+2
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-04-23um: ensure `make ARCH=um mrproper` removes arch/$(SUBARCH)/include/generated/Vitor Massaru Iha1-0/+1
In this workflow: $ make ARCH=um defconfig && make ARCH=um -j8 [snip] $ make ARCH=um mrproper [snip] $ make ARCH=um defconfig O=./build_um && make ARCH=um -j8 O=./build_um [snip] CC scripts/mod/empty.o In file included from ../include/linux/types.h:6, from ../include/linux/mod_devicetable.h:12, from ../scripts/mod/devicetable-offsets.c:3: ../include/uapi/linux/types.h:5:10: fatal error: asm/types.h: No such file or directory 5 | #include <asm/types.h> | ^~~~~~~~~~~~~ compilation terminated. make[2]: *** [../scripts/Makefile.build:100: scripts/mod/devicetable-offsets.s] Error 1 make[2]: *** Waiting for unfinished jobs.... make[1]: *** [/home/iha/sdb/opensource/lkmp/linux-kselftest.git/Makefile:1140: prepare0] Error 2 make[1]: Leaving directory '/home/iha/sdb/opensource/lkmp/linux-kselftest.git/build_um' make: *** [Makefile:180: sub-make] Error 2 The cause of the error was because arch/$(SUBARCH)/include/generated files weren't properly cleaned by `make ARCH=um mrproper`. Fixes: a788b2ed81ab ("kbuild: check arch/$(SRCARCH)/include/generated before out-of-tree build") Reported-by: Theodore Ts'o <tytso@mit.edu> Suggested-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Vitor Massaru Iha <vitor@massaru.org> Reviewed-by: Brendan Higgins <brendanhiggins@google.com> Tested-by: Brendan Higgins <brendanhiggins@google.com> Link: https://groups.google.com/forum/#!msg/kunit-dev/QmA27YEgEgI/hvS1kiz2CwAJ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-04-23arch: split MODULE_ARCH_VERMAGIC definitions out to <asm/vermagic.h>Masahiro Yamada21-222/+274
As the bug report [1] pointed out, <linux/vermagic.h> must be included after <linux/module.h>. I believe we should not impose any include order restriction. We often sort include directives alphabetically, but it is just coding style convention. Technically, we can include header files in any order by making every header self-contained. Currently, arch-specific MODULE_ARCH_VERMAGIC is defined in <asm/module.h>, which is not included from <linux/vermagic.h>. Hence, the straight-forward fix-up would be as follows: |--- a/include/linux/vermagic.h |+++ b/include/linux/vermagic.h |@@ -1,5 +1,6 @@ | /* SPDX-License-Identifier: GPL-2.0 */ | #include <generated/utsrelease.h> |+#include <linux/module.h> | | /* Simply sanity version stamp for modules. */ | #ifdef CONFIG_SMP This works enough, but for further cleanups, I split MODULE_ARCH_VERMAGIC definitions into <asm/vermagic.h>. With this, <linux/module.h> and <linux/vermagic.h> will be orthogonal, and the location of MODULE_ARCH_VERMAGIC definitions will be consistent. For arc and ia64, MODULE_PROC_FAMILY is only used for defining MODULE_ARCH_VERMAGIC. I squashed it. For hexagon, nds32, and xtensa, I removed <asm/modules.h> entirely because they contained nothing but MODULE_ARCH_VERMAGIC definition. Kbuild will automatically generate <asm/modules.h> at build-time, wrapping <asm-generic/module.h>. [1] https://lore.kernel.org/lkml/20200411155623.GA22175@zn.tnic Reported-by: Borislav Petkov <bp@suse.de> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Jessica Yu <jeyu@kernel.org>
2020-04-22x86, sched: Move check for CPU type to caller functionGiovanni Gherdovich1-4/+2
Improve readability of the function intel_set_max_freq_ratio() by moving the check for KNL CPUs there, together with checks for GLM and SKX. Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lkml.kernel.org/r/20200416054745.740-5-ggherdovich@suse.cz
2020-04-22x86, sched: Don't enable static key when starting secondary CPUsPeter Zijlstra (Intel)1-7/+14
The static key arch_scale_freq_key only needs to be enabled once (at boot). This change fixes a bug by which the key was enabled every time cpu0 is started, even as a secondary CPU during cpu hotplug. Secondary CPUs are started from the idle thread: setting a static key from there means acquiring a lock and may result in sleeping in the idle task, causing CPU lockup. Another consequence of this change is that init_counter_refs() is now called on each CPU correctly; previously the function on_each_cpu() was used, but it was called at boot when the only online cpu is cpu0. [ggherdovich@suse.cz: Tested and wrote changelog] Fixes: 1567c3e3467c ("x86, sched: Add support for frequency invariance") Reported-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lkml.kernel.org/r/20200416054745.740-4-ggherdovich@suse.cz
2020-04-22x86, sched: Account for CPUs with less than 4 cores in freq. invarianceGiovanni Gherdovich1-3/+8
If a CPU has less than 4 physical cores, MSR_TURBO_RATIO_LIMIT will rightfully report that the 4C turbo ratio is zero. In such cases, use the 1C turbo ratio instead for frequency invariance calculations. Fixes: 1567c3e3467c ("x86, sched: Add support for frequency invariance") Reported-by: Like Xu <like.xu@linux.intel.com> Reported-by: Neil Rickert <nwr10cst-oslnx@yahoo.com> Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Dave Kleikamp <dave.kleikamp@oracle.com> Link: https://lkml.kernel.org/r/20200416054745.740-3-ggherdovich@suse.cz
2020-04-22x86, sched: Bail out of frequency invariance if base frequency is unknownGiovanni Gherdovich1-0/+9
Some hypervisors such as VMWare ESXi 5.5 advertise support for X86_FEATURE_APERFMPERF but then fill all MSR's with zeroes. In particular, MSR_PLATFORM_INFO set to zero tricks the code that wants to know the base clock frequency of the CPU (highest non-turbo frequency), producing a division by zero when computing the ratio turbo_freq/base_freq necessary for frequency invariant accounting. It is to be noted that even if MSR_PLATFORM_INFO contained the appropriate data, APERF and MPERF are constantly zero on ESXi 5.5, thus freq-invariance couldn't be done in principle (not that it would make a lot of sense in a VM anyway). The real problem is advertising X86_FEATURE_APERFMPERF. This appears to be fixed in more recent versions: ESXi 6.7 doesn't advertise that feature. Fixes: 1567c3e3467c ("x86, sched: Add support for frequency invariance") Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lkml.kernel.org/r/20200416054745.740-2-ggherdovich@suse.cz
2020-04-22perf/x86/cstate: Add Jasper Lake CPU supportHarry Pan1-0/+1
The Jasper Lake processor is Tremont microarchitecture, reuse the glm_cstates table of Goldmont and Goldmont Plus to enable the C-states residency profiling. Signed-off-by: Harry Pan <harry.pan@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200402190658.1.Ic02e891daac41303aed1f2fc6c64f6110edd27bd@changeid
2020-04-22s390/pci: do not set affinity for floating irqsNiklas Schnelle1-2/+3
with the introduction of CPU directed interrupts the kernel parameter pci=force_floating was introduced to fall back to the previous behavior using floating irqs. However we were still setting the affinity in that case, both in __irq_alloc_descs() and via the irq_set_affinity callback in struct irq_chip. For the former only set the affinity in the directed case. The latter is explicitly set in zpci_directed_irq_init() so we can just leave it unset for the floating case. Fixes: e979ce7bced2 ("s390/pci: provide support for CPU directed interrupts") Co-developed-by: Alexander Schmidt <alexs@linux.ibm.com> Signed-off-by: Alexander Schmidt <alexs@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2020-04-22s390/ftrace: fix potential crashes when switching tracersPhilipp Rudo3-4/+4
Switching tracers include instruction patching. To prevent that a instruction is patched while it's read the instruction patching is done in stop_machine 'context'. This also means that any function called during stop_machine must not be traced. Thus add 'notrace' to all functions called within stop_machine. Fixes: 1ec2772e0c3c ("s390/diag: add a statistic for diagnose calls") Fixes: 38f2c691a4b3 ("s390: improve wait logic of stop_machine") Fixes: 4ecf0a43e729 ("processor: get rid of cpu_relax_yield") Signed-off-by: Philipp Rudo <prudo@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2020-04-22powerpc/mm: Fix CONFIG_PPC_KUAP_DEBUG on PPC32Christophe Leroy2-2/+2
CONFIG_PPC_KUAP_DEBUG is not selectable because it depends on PPC_32 which doesn't exists. Fixing it leads to a deadlock due to a vital register getting clobbered in _switch(). Change dependency to PPC32 and use r0 instead of r4 in _switch() Fixes: e2fb9f544431 ("powerpc/32: Prepare for Kernel Userspace Access Protection") Cc: stable@vger.kernel.org # v5.2+ Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/540242f7d4573f7cdf1b3bf46bb35f743b2cd68f.1587124651.git.christophe.leroy@c-s.fr
2020-04-22powerpc/8xx: Fix STRICT_KERNEL_RWX startup test failureChristophe Leroy1-0/+3
WRITE_RO lkdtm test works. But when selecting CONFIG_DEBUG_RODATA_TEST, the kernel reports rodata_test: test data was not read only This is because when rodata test runs, there are still old entries in TLB. Flush TLB after setting kernel pages RO or NX. Fixes: d5f17ee96447 ("powerpc/8xx: don't disable large TLBs with CONFIG_STRICT_KERNEL_RWX") Cc: stable@vger.kernel.org # v5.1+ Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/485caac75f195f18c11eb077b0031fdd2bb7fb9e.1587361039.git.christophe.leroy@c-s.fr
2020-04-21riscv: sbi: Fix undefined reference to sbi_shutdownKefeng Wang1-5/+8
There is no shutdown call in SBI v0.2, only set pm_power_off when RISCV_SBI_V01 enabled to fix following build error, riscv64-linux-ld: arch/riscv/kernel/sbi.o: in function `sbi_power_off': sbi.c:(.text+0xe): undefined reference to `sbi_shutdown Fixes: efca13989250 ("RISC-V: Introduce a new config for SBI v0.1") Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-21riscv: sbi: Correct sbi_shutdown() and sbi_clear_ipi() exportKefeng Wang1-2/+2
Fix incorrect EXPORT_SYMBOL(). Fixes: efca13989250 ("RISC-V: Introduce a new config for SBI v0.1") Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-21riscv: fix vdso build with lldIlie Halip1-3/+3
When building with the LLVM linker this error occurrs: LD arch/riscv/kernel/vdso/vdso-syms.o ld.lld: error: no input files This happens because the lld treats -R as an alias to -rpath, as opposed to ld where -R means --just-symbols. Use the long option name for compatibility between the two. Link: https://github.com/ClangBuiltLinux/linux/issues/805 Reported-by: Dmitry Golovin <dima@golovin.in> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Ilie Halip <ilie.halip@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-21Merge branch 'akpm' (patches from Andrew)Linus Torvalds2-2/+2
Merge misc fixes from Andrew Morton: "15 fixes" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: tools/vm: fix cross-compile build coredump: fix null pointer dereference on coredump mm: shmem: disable interrupt when acquiring info->lock in userfaultfd_copy path shmem: fix possible deadlocks on shmlock_user_lock vmalloc: fix remap_vmalloc_range() bounds checks mm/shmem: fix build without THP mm/ksm: fix NULL pointer dereference when KSM zero page is enabled tools/build: tweak unused value workaround checkpatch: fix a typo in the regex for $allocFunctions mm, gup: return EINTR when gup is interrupted by fatal signals mm/hugetlb: fix a addressing exception caused by huge_pte_offset MAINTAINERS: add an entry for kfifo mm/userfaultfd: disable userfaultfd-wp on x86_32 slub: avoid redzone when choosing freepointer location sh: fix build error in mm/init.c
2020-04-21mm/userfaultfd: disable userfaultfd-wp on x86_32Peter Xu1-1/+1
Userfaultfd-wp is not yet working on 32bit hosts, but it's accidentally enabled previously. Disable it. Fixes: 5a281062af1d ("userfaultfd: wp: add WP pagetable tracking to x86") Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Hillf Danton <hdanton@sina.com> Link: http://lkml.kernel.org/r/20200413141608.109211-1-peterx@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-21sh: fix build error in mm/init.cMasahiro Yamada1-1/+1
The closing parenthesis is missing. Fixes: bfeb022f8fe4 ("mm/memory_hotplug: add pgprot_t to mhp_params") Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Logan Gunthorpe <logang@deltatee.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Link: http://lkml.kernel.org/r/20200413014743.16353-1-masahiroy@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-21RISC-V: stacktrace: Declare sp_in_global outside ifdefGuenter Roeck1-2/+2
riscv:allnoconfig and riscv:tinyconfig fail to compile. arch/riscv/kernel/stacktrace.c: In function 'walk_stackframe': arch/riscv/kernel/stacktrace.c:78:8: error: 'sp_in_global' undeclared sp_in_global is declared inside CONFIG_FRAME_POINTER but used outside of it. Fixes: 52e7c52d2ded ("RISC-V: Stop relying on GCC's register allocator's hueristics") Signed-off-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-21arm64: sync kernel APIAKey when installingMark Rutland1-3/+6
A direct write to a APxxKey_EL1 register requires a context synchronization event to ensure that indirect reads made by subsequent instructions (e.g. AUTIASP, PACIASP) observe the new value. When we initialize the boot task's APIAKey in boot_init_stack_canary() via ptrauth_keys_switch_kernel() we miss the necessary ISB, and so there is a window where instructions are not guaranteed to use the new APIAKey value. This has been observed to result in boot-time crashes where PACIASP and AUTIASP within a function used a mixture of the old and new key values. Fix this by having ptrauth_keys_switch_kernel() synchronize the new key value with an ISB. At the same time, __ptrauth_key_install() is renamed to __ptrauth_key_install_nosync() so that it is obvious that this performs no synchronization itself. Fixes: 28321582334c261c ("arm64: initialize ptrauth keys for kernel booting task") Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reported-by: Will Deacon <will@kernel.org> Cc: Amit Daniel Kachhap <amit.kachhap@arm.com> Cc: Marc Zyngier <maz@kernel.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Tested-by: Will Deacon <will@kernel.org>
2020-04-21Merge tag 'kvm-ppc-fixes-5.7-1' of ↵Paolo Bonzini2-8/+10
git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into kvm-master PPC KVM fix for 5.7 - Fix a regression introduced in the last merge window, which results in guests in HPT mode dying randomly.
2020-04-21Merge tag 'kvm-s390-master-5.7-2' of ↵Paolo Bonzini1224-15645/+34962
git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvm-master KVM: s390: Fix for 5.7 and maintainer update - Silence false positive lockdep warning - add Claudio as reviewer
2020-04-21s390/mm: fix page table upgrade vs 2ndary address mode accessesChristian Borntraeger2-2/+18
A page table upgrade in a kernel section that uses secondary address mode will mess up the kernel instructions as follows: Consider the following scenario: two threads are sharing memory. On CPU1 thread 1 does e.g. strnlen_user(). That gets to old_fs = enable_sacf_uaccess(); len = strnlen_user_srst(src, size); and " la %2,0(%1)\n" " la %3,0(%0,%1)\n" " slgr %0,%0\n" " sacf 256\n" "0: srst %3,%2\n" in strnlen_user_srst(). At that point we are in secondary space mode, control register 1 points to kernel page table and instruction fetching happens via c1, rather than usual c13. Interrupts are not disabled, for obvious reasons. On CPU2 thread 2 does MAP_FIXED mmap(), forcing the upgrade of page table from 3-level to e.g. 4-level one. We'd allocated new top-level table, set it up and now we hit this: notify = 1; spin_unlock_bh(&mm->page_table_lock); } if (notify) on_each_cpu(__crst_table_upgrade, mm, 0); OK, we need to actually change over to use of new page table and we need that to happen in all threads that are currently running. Which happens to include the thread 1. IPI is delivered and we have static void __crst_table_upgrade(void *arg) { struct mm_struct *mm = arg; if (current->active_mm == mm) set_user_asce(mm); __tlb_flush_local(); } run on CPU1. That does static inline void set_user_asce(struct mm_struct *mm) { S390_lowcore.user_asce = mm->context.asce; OK, user page table address updated... __ctl_load(S390_lowcore.user_asce, 1, 1); ... and control register 1 set to it. clear_cpu_flag(CIF_ASCE_PRIMARY); } IPI is run in home space mode, so it's fine - insns are fetched using c13, which always points to kernel page table. But as soon as we return from the interrupt, previous PSW is restored, putting CPU1 back into secondary space mode, at which point we no longer get the kernel instructions from the kernel mapping. The fix is to only fixup the control registers that are currently in use for user processes during the page table update. We must also disable interrupts in enable_sacf_uaccess to synchronize the cr and thread.mm_segment updates against the on_each-cpu. Fixes: 0aaba41b58bc ("s390: remove all code using the access register mode") Cc: stable@vger.kernel.org # 4.15+ Reported-by: Al Viro <viro@zeniv.linux.org.uk> Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> References: CVE-2020-11884 Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2020-04-21x86/hyperv: Suspend/resume the VP assist page for hibernationDexuan Cui1-2/+10
Unlike the other CPUs, CPU0 is never offlined during hibernation, so in the resume path, the "new" kernel's VP assist page is not suspended (i.e. not disabled), and later when we jump to the "old" kernel, the page is not properly re-enabled for CPU0 with the allocated page from the old kernel. So far, the VP assist page is used by hv_apic_eoi_write(), and is also used in the case of nested virtualization (running KVM atop Hyper-V). For hv_apic_eoi_write(), when the page is not properly re-enabled, hvp->apic_assist is always 0, so the HV_X64_MSR_EOI MSR is always written. This is not ideal with respect to performance, but Hyper-V can still correctly handle this according to the Hyper-V spec; nevertheless, Linux still must update the Hyper-V hypervisor with the correct VP assist page to prevent Hyper-V from writing to the stale page, which causes guest memory corruption and consequently may have caused the hangs and triple faults seen during non-boot CPUs resume. Fix the issue by calling hv_cpu_die()/hv_cpu_init() in the syscore ops. Without the fix, hibernation can fail at a rate of 1/300 ~ 1/500. With the fix, hibernation can pass a long-haul test of 2000 runs. In the case of nested virtualization, disabling/reenabling the assist page upon hibernation may be unsafe if there are active L2 guests. It looks KVM should be enhanced to abort the hibernation request if there is any active L2 guest. Fixes: 05bd330a7fd8 ("x86/hyperv: Suspend/resume the hypercall page for hibernation") Cc: stable@vger.kernel.org Signed-off-by: Dexuan Cui <decui@microsoft.com> Link: https://lore.kernel.org/r/1587437171-2472-1-git-send-email-decui@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>