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2021-09-22KVM: x86: Query vcpu->vcpu_idx directly and drop its accessorSean Christopherson
Read vcpu->vcpu_idx directly instead of bouncing through the one-line wrapper, kvm_vcpu_get_idx(), and drop the wrapper. The wrapper is a remnant of the original implementation and serves no purpose; remove it before it gains more users. Back when kvm_vcpu_get_idx() was added by commit 497d72d80a78 ("KVM: Add kvm_vcpu_get_idx to get vcpu index in kvm->vcpus"), the implementation was more than just a simple wrapper as vcpu->vcpu_idx did not exist and retrieving the index meant walking over the vCPU array to find the given vCPU. When vcpu_idx was introduced by commit 8750e72a79dd ("KVM: remember position in kvm->vcpus array"), the helper was left behind, likely to avoid extra thrash (but even then there were only two users, the original arm usage having been removed at some point in the past). No functional change intended. Suggested-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20210910183220.2397812-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-22kvm: fix wrong exception emulation in check_rdtscHou Wenlong
According to Intel's SDM Vol2 and AMD's APM Vol3, when CR4.TSD is set, use rdtsc/rdtscp instruction above privilege level 0 should trigger a #GP. Fixes: d7eb82030699e ("KVM: SVM: Add intercept checks for remaining group7 instructions") Signed-off-by: Hou Wenlong <houwenlong93@linux.alibaba.com> Message-Id: <1297c0dd3f1bb47a6d089f850b629c7aa0247040.1629257115.git.houwenlong93@linux.alibaba.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Jim Mattson <jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-22KVM: SEV: Pin guest memory for write for RECEIVE_UPDATE_DATASean Christopherson
Require the target guest page to be writable when pinning memory for RECEIVE_UPDATE_DATA. Per the SEV API, the PSP writes to guest memory: The result is then encrypted with GCTX.VEK and written to the memory pointed to by GUEST_PADDR field. Fixes: 15fb7de1a7f5 ("KVM: SVM: Add KVM_SEV_RECEIVE_UPDATE_DATA command") Cc: stable@vger.kernel.org Cc: Peter Gonda <pgonda@google.com> Cc: Marc Orr <marcorr@google.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210914210951.2994260-2-seanjc@google.com> Reviewed-by: Brijesh Singh <brijesh.singh@amd.com> Reviewed-by: Peter Gonda <pgonda@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-22KVM: SVM: fix missing sev_decommission in sev_receive_startMingwei Zhang
DECOMMISSION the current SEV context if binding an ASID fails after RECEIVE_START. Per AMD's SEV API, RECEIVE_START generates a new guest context and thus needs to be paired with DECOMMISSION: The RECEIVE_START command is the only command other than the LAUNCH_START command that generates a new guest context and guest handle. The missing DECOMMISSION can result in subsequent SEV launch failures, as the firmware leaks memory and might not able to allocate more SEV guest contexts in the future. Note, LAUNCH_START suffered the same bug, but was previously fixed by commit 934002cd660b ("KVM: SVM: Call SEV Guest Decommission if ASID binding fails"). Cc: Alper Gun <alpergun@google.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: David Rienjes <rientjes@google.com> Cc: Marc Orr <marcorr@google.com> Cc: John Allen <john.allen@amd.com> Cc: Peter Gonda <pgonda@google.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Vipin Sharma <vipinsh@google.com> Cc: stable@vger.kernel.org Reviewed-by: Marc Orr <marcorr@google.com> Acked-by: Brijesh Singh <brijesh.singh@amd.com> Fixes: af43cbbf954b ("KVM: SVM: Add support for KVM_SEV_RECEIVE_START command") Signed-off-by: Mingwei Zhang <mizhang@google.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210912181815.3899316-1-mizhang@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-22KVM: SEV: Acquire vcpu mutex when updating VMSAPeter Gonda
The update-VMSA ioctl touches data stored in struct kvm_vcpu, and therefore should not be performed concurrently with any VCPU ioctl that might cause KVM or the processor to use the same data. Adds vcpu mutex guard to the VMSA updating code. Refactors out __sev_launch_update_vmsa() function to deal with per vCPU parts of sev_launch_update_vmsa(). Fixes: ad73109ae7ec ("KVM: SVM: Provide support to launch and run an SEV-ES guest") Signed-off-by: Peter Gonda <pgonda@google.com> Cc: Marc Orr <marcorr@google.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: kvm@vger.kernel.org Cc: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org Message-Id: <20210915171755.3773766-1-pgonda@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-22KVM: nVMX: fix comments of handle_vmon()Yu Zhang
"VMXON pointer" is saved in vmx->nested.vmxon_ptr since commit 3573e22cfeca ("KVM: nVMX: additional checks on vmxon region"). Also, handle_vmptrld() & handle_vmclear() now have logic to check the VMCS pointer against the VMXON pointer. So just remove the obsolete comments of handle_vmon(). Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> Message-Id: <20210908171731.18885-1-yu.c.zhang@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-22KVM: x86: Handle SRCU initialization failure during page track initHaimin Zhang
Check the return of init_srcu_struct(), which can fail due to OOM, when initializing the page track mechanism. Lack of checking leads to a NULL pointer deref found by a modified syzkaller. Reported-by: TCS Robot <tcs_robot@tencent.com> Signed-off-by: Haimin Zhang <tcs_kernel@tencent.com> Message-Id: <1630636626-12262-1-git-send-email-tcs_kernel@tencent.com> [Move the call towards the beginning of kvm_arch_init_vm. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-22KVM: VMX: Remove defunct "nr_active_uret_msrs" fieldSean Christopherson
Remove vcpu_vmx.nr_active_uret_msrs and its associated comment, which are both defunct now that KVM keeps the list constant and instead explicitly tracks which entries need to be loaded into hardware. No functional change intended. Fixes: ee9d22e08d13 ("KVM: VMX: Use flag to indicate "active" uret MSRs instead of sorting list") Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210908002401.1947049-1-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-22KVM: x86: Clear KVM's cached guest CR3 at RESET/INITSean Christopherson
Explicitly zero the guest's CR3 and mark it available+dirty at RESET/INIT. Per Intel's SDM and AMD's APM, CR3 is zeroed at both RESET and INIT. For RESET, this is a nop as vcpu is zero-allocated. For INIT, the bug has likely escaped notice because no firmware/kernel puts its page tables root at PA=0, let alone relies on INIT to get the desired CR3 for such page tables. Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210921000303.400537-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-22KVM: x86: Mark all registers as avail/dirty at vCPU creationSean Christopherson
Mark all registers as available and dirty at vCPU creation, as the vCPU has obviously not been loaded into hardware, let alone been given the chance to be modified in hardware. On SVM, reading from "uninitialized" hardware is a non-issue as VMCBs are zero allocated (thus not truly uninitialized) and hardware does not allow for arbitrary field encoding schemes. On VMX, backing memory for VMCSes is also zero allocated, but true initialization of the VMCS _technically_ requires VMWRITEs, as the VMX architectural specification technically allows CPU implementations to encode fields with arbitrary schemes. E.g. a CPU could theoretically store the inverted value of every field, which would result in VMREAD to a zero-allocated field returns all ones. In practice, only the AR_BYTES fields are known to be manipulated by hardware during VMREAD/VMREAD; no known hardware or VMM (for nested VMX) does fancy encoding of cacheable field values (CR0, CR3, CR4, etc...). In other words, this is technically a bug fix, but practically speakings it's a glorified nop. Failure to mark registers as available has been a lurking bug for quite some time. The original register caching supported only GPRs (+RIP, which is kinda sorta a GPR), with the masks initialized at ->vcpu_reset(). That worked because the two cacheable registers, RIP and RSP, are generally speaking not read as side effects in other flows. Arguably, commit aff48baa34c0 ("KVM: Fetch guest cr3 from hardware on demand") was the first instance of failure to mark regs available. While _just_ marking CR3 available during vCPU creation wouldn't have fixed the VMREAD from an uninitialized VMCS bug because ept_update_paging_mode_cr0() unconditionally read vmcs.GUEST_CR3, marking CR3 _and_ intentionally not reading GUEST_CR3 when it's available would have avoided VMREAD to a technically-uninitialized VMCS. Fixes: aff48baa34c0 ("KVM: Fetch guest cr3 from hardware on demand") Fixes: 6de4f3ada40b ("KVM: Cache pdptrs") Fixes: 6de12732c42c ("KVM: VMX: Optimize vmx_get_rflags()") Fixes: 2fb92db1ec08 ("KVM: VMX: Cache vmcs segment fields") Fixes: bd31fe495d0d ("KVM: VMX: Add proper cache tracking for CR0") Fixes: f98c1e77127d ("KVM: VMX: Add proper cache tracking for CR4") Fixes: 5addc235199f ("KVM: VMX: Cache vmcs.EXIT_QUALIFICATION using arch avail_reg flags") Fixes: 8791585837f6 ("KVM: VMX: Cache vmcs.EXIT_INTR_INFO using arch avail_reg flags") Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210921000303.400537-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-22entry: rseq: Call rseq_handle_notify_resume() in tracehook_notify_resume()Sean Christopherson
Invoke rseq_handle_notify_resume() from tracehook_notify_resume() now that the two function are always called back-to-back by architectures that have rseq. The rseq helper is stubbed out for architectures that don't support rseq, i.e. this is a nop across the board. Note, tracehook_notify_resume() is horribly named and arguably does not belong in tracehook.h as literally every line of code in it has nothing to do with tracing. But, that's been true since commit a42c6ded827d ("move key_repace_session_keyring() into tracehook_notify_resume()") first usurped tracehook_notify_resume() back in 2012. Punt cleaning that mess up to future patches. No functional change intended. Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210901203030.1292304-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-19Merge tag 'x86_urgent_for_v5.15_rc2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Borislav Petkov: - Prevent a infinite loop in the MCE recovery on return to user space, which was caused by a second MCE queueing work for the same page and thereby creating a circular work list. - Make kern_addr_valid() handle existing PMD entries, which are marked not present in the higher level page table, correctly instead of blindly dereferencing them. - Pass a valid address to sanitize_phys(). This was caused by the mixture of inclusive and exclusive ranges. memtype_reserve() expect 'end' being exclusive, but sanitize_phys() wants it inclusive. This worked so far, but with end being the end of the physical address space the fail is exposed. - Increase the maximum supported GPIO numbers for 64bit. Newer SoCs exceed the previous maximum. * tag 'x86_urgent_for_v5.15_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mce: Avoid infinite loop for copy from user recovery x86/mm: Fix kern_addr_valid() to cope with existing but not present entries x86/platform: Increase maximum GPIO number for X86_64 x86/pat: Pass valid address to sanitize_phys()
2021-09-19Merge tag 'powerpc-5.15-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull powerpc fixes from Michael Ellerman: - Fix crashes when scv (System Call Vectored) is used to make a syscall when a transaction is active, on Power9 or later. - Fix bad interactions between rfscv (Return-from scv) and Power9 fake-suspend mode. - Fix crashes when handling machine checks in LPARs using the Hash MMU. - Partly revert a recent change to our XICS interrupt controller code, which broke the recently added Microwatt support. Thanks to Cédric Le Goater, Eirik Fuller, Ganesh Goudar, Gustavo Romero, Joel Stanley, Nicholas Piggin. * tag 'powerpc-5.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/xics: Set the IRQ chip data for the ICS native backend powerpc/mce: Fix access error in mce handler KVM: PPC: Book3S HV: Tolerate treclaim. in fake-suspend mode changing registers powerpc/64s: system call rfscv workaround for TM bugs selftests/powerpc: Add scv versions of the basic TM syscall tests powerpc/64s: system call scv tabort fix for corrupt irq soft-mask state
2021-09-19Merge tag 'kbuild-fixes-v5.15' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild fixes from Masahiro Yamada: - Fix bugs in checkkconfigsymbols.py - Fix missing sys import in gen_compile_commands.py - Fix missing FORCE warning for ARCH=sh builds - Fix -Wignored-optimization-argument warnings for Clang builds - Turn -Wignored-optimization-argument into an error in order to stop building instead of sprinkling warnings * tag 'kbuild-fixes-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: Add -Werror=ignored-optimization-argument to CLANG_FLAGS x86/build: Do not add -falign flags unconditionally for clang kbuild: Fix comment typo in scripts/Makefile.modpost sh: Add missing FORCE prerequisites in Makefile gen_compile_commands: fix missing 'sys' package checkkconfigsymbols.py: Remove skipping of help lines in parse_kconfig_file checkkconfigsymbols.py: Forbid passing 'HEAD' to --commit
2021-09-19alpha: enable GENERIC_PCI_IOMAP unconditionallyLinus Torvalds
With the previous commit (9caea0007601: "parisc: Declare pci_iounmap() parisc version only when CONFIG_PCI enabled") we can now enable GENERIC_PCI_IOMAP unconditionally on alpha, and if PCI is not enabled we will just get the nice empty helper functions that allow mixed-bus drivers to build. Example driver: the old 3com/3c59x.c driver works with either the PCI or the EISA version of the 3x59x card, but wouldn't build in an EISA-only configuration because of missing pci_iomap() and pci_iounmap() dummy wrappers. Most of the other PCI infrastructure just becomes empty wrappers even without GENERIC_PCI_IOMAP, and it's not obvious that the pci_iomap functionality shouldn't do the same, but this works. Cc: Ulrich Teichert <krypton@ulrich-teichert.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-19parisc: Declare pci_iounmap() parisc version only when CONFIG_PCI enabledHelge Deller
Linus noticed odd declaration rules for pci_iounmap() in iomap.h and pci_iomap.h, where it dependend on either NO_GENERIC_PCI_IOPORT_MAP or GENERIC_IOMAP when CONFIG_PCI was disabled. Testing on parisc seems to indicate that we need pci_iounmap() only when CONFIG_PCI is enabled, so the declaration of pci_iounmap() can be moved cleanly into pci_iomap.h in sync with the declarations of pci_iomap(). Link: https://lore.kernel.org/all/CAHk-=wjRrh98pZoQ+AzfWmsTZacWxTJKXZ9eKU2X_0+jM=O8nw@mail.gmail.com/ Signed-off-by: Helge Deller <deller@gmx.de> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Fixes: 97a29d59fc22 ("[PARISC] fix compile break caused by iomap: make IOPORT/PCI mapping functions conditional") Cc: Arnd Bergmann <arnd@arndb.de> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Ulrich Teichert <krypton@ulrich-teichert.org> Cc: James Bottomley <James.Bottomley@hansenpartnership.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-19x86/build: Do not add -falign flags unconditionally for clangNathan Chancellor
clang does not support -falign-jumps and only recently gained support for -falign-loops. When one of the configuration options that adds these flags is enabled, clang warns and all cc-{disable-warning,option} that follow fail because -Werror gets added to test for the presence of this warning: clang-14: warning: optimization flag '-falign-jumps=0' is not supported [-Wignored-optimization-argument] To resolve this, add a couple of cc-option calls when building with clang; gcc has supported these options since 3.2 so there is no point in testing for their support. -falign-functions was implemented in clang-7, -falign-loops was implemented in clang-14, and -falign-jumps has not been implemented yet. Link: https://lore.kernel.org/r/YSQE2f5teuvKLkON@Ryzen-9-3900X.localdomain/ Link: https://lore.kernel.org/r/20210824022640.2170859-2-nathan@kernel.org/ Reported-by: kernel test robot <lkp@intel.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Acked-by: Borislav Petkov <bp@suse.de> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-09-19sh: Add missing FORCE prerequisites in MakefileGeert Uytterhoeven
make: arch/sh/boot/Makefile:87: FORCE prerequisite is missing Add the missing FORCE prerequisites for all build targets identified by "make help". Fixes: e1f86d7b4b2a5213 ("kbuild: warn if FORCE is missing for if_changed(_dep,_rule) and filechk") Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-09-18alpha: move __udiv_qrnnd library function to arch/alpha/lib/Linus Torvalds
We already had the implementation for __udiv_qrnnd (unsigned divide for multi-precision arithmetic) as part of the alpha math emulation code. But you can disable the math emulation code - even if you shouldn't - and then the MPI code that actually wants this functionality (and is needed by various crypto functions) will fail to build. So move the extended-precision divide code to be a regular library function, just like all the regular division code is. That way ie is available regardless of math-emulation. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-18alpha: mark 'Jensen' platform as no longer brokenLinus Torvalds
Ok, it almost certainly is still broken on actual hardware, but the immediate reason for it having been marked BROKEN was a build error that is fixed by just making sure the low-level IO header file is included sufficiently early that the __EXTERN_INLINE hackery takes effect. This was marked broken back in 2017 by commit 1883c9f49d02 ("alpha: mark jensen as broken"), but Ulrich Teichert made me look at it as part of my cross-build work to make sure -Werror actually does the right thing. There are lots of alpha configurations that do not build cleanly, but now it's no longer because Jensen wouldn't be buildable. That said, because the Jensen platform doesn't force PCI to be enabled (Jensen only had EISA), it ends up being somewhat interesting as a source of odd configs. Reported-by: Ulrich Teichert <krypton@ulrich-teichert.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-18Merge tag 's390-5.15-3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull s390 fixes from Vasily Gorbik: - Fix potential out-of-range access during secure boot facility detection. - Fully validate the VMA before calling follow_pte() in pci code. - Remove arch specific WARN_DYNAMIC_STACK config option. - Fix zcrypto kernel doc comments. - Update defconfigs. * tag 's390-5.15-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: s390: remove WARN_DYNAMIC_STACK s390/ap: fix kernel doc comments s390: update defconfigs s390/sclp: fix Secure-IPL facility detection s390/pci_mmio: fully validate the VMA before calling follow_pte()
2021-09-18alpha: make 'Jensen' IO functions build againLinus Torvalds
The Jensen IO functions are overly copmplicated because some of the IO addresses refer to special 'local IO' ports, and they get accessed differently. That then makes gcc not actually inline them, and since they were marked "extern inline" when included through the regular <asm/io.h> path, and then only marked "inline" when included from sys_jensen.c, you never necessarily got a body for the IO functions at all. The intent of the sys_jensen.c code is to actually get the non-inlined copy generated, so remove the 'inline' from the magic macro that is supposed to sort this all out. Also, do not mix 'extern inline' functions (that may or may not be inlined and will not generate a function body if they are not) with 'static inline' (that _will_ generate a function body when not inlined). Because gcc will complain about this situation: error: ‘jensen_bus_outb’ is static but used in inline function ‘jensen_outb’ which is not static because gcc basically doesn't know whether to generate a body for that static inline function or not for that call site. So make all of these use that __EXTERN_INLINE marker. Gcc will generally not inline these things on use, and then generate the function body out-of-line in sys_jensen.c. This makes the core IO functions build for the alpha Jensen config. Not that the rest then builds, because it turns out Jensen also doesn't enable PCI, which then makes other drievrs very unhappy, but that's a separate issue. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-17Merge tag 'dma-mapping-5.15-1' of git://git.infradead.org/users/hch/dma-mappingLinus Torvalds
Pull dma-mapping fixes from Christoph Hellwig: - page align size in sparc32 arch_dma_alloc (Andreas Larsson) - tone down a new dma-debug message (Hamza Mahfooz) - fix the kerneldoc for dma_map_sg_attrs (me) * tag 'dma-mapping-5.15-1' of git://git.infradead.org/users/hch/dma-mapping: sparc32: page align size in arch_dma_alloc dma-debug: prevent an error message from causing runtime problems dma-mapping: fix the kerneldoc for dma_map_sg_attrs
2021-09-17Merge tag 'arm64-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 fixes and cleanups from Catalin Marinas: - Fix the memset() size when re-initialising the SVE state. - Mark __stack_chk_guard as __ro_after_init. - Remove duplicate include. * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64: Mark __stack_chk_guard as __ro_after_init arm64/kernel: remove duplicate include in process.c arm64/sve: Use correct size when reinitialising SVE state
2021-09-17Merge tag 'for-linus-5.15b-rc2-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen fixes from Juergen Gross: - The first hunk of a Xen swiotlb fixup series fixing multiple minor issues and doing some small cleanups - Some further Xen related fixes avoiding WARN() splats when running as Xen guests or dom0 - A Kconfig fix allowing the pvcalls frontend to be built as a module * tag 'for-linus-5.15b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: swiotlb-xen: drop DEFAULT_NSLABS swiotlb-xen: arrange to have buffer info logged swiotlb-xen: drop leftover __ref swiotlb-xen: limit init retries swiotlb-xen: suppress certain init retries swiotlb-xen: maintain slab count properly swiotlb-xen: fix late init retry swiotlb-xen: avoid double free xen/pvcalls: backend can be a module xen: fix usage of pmd_populate in mremap for pv guests xen: reset legacy rtc flag for PV domU PM: base: power: don't try to use non-existing RTC for storing data xen/balloon: use a kernel thread instead a workqueue
2021-09-16alpha: Declare virt_to_phys and virt_to_bus parameter as pointer to volatileGuenter Roeck
Some drivers pass a pointer to volatile data to virt_to_bus() and virt_to_phys(), and that works fine. One exception is alpha. This results in a number of compile errors such as drivers/net/wan/lmc/lmc_main.c: In function 'lmc_softreset': drivers/net/wan/lmc/lmc_main.c:1782:50: error: passing argument 1 of 'virt_to_bus' discards 'volatile' qualifier from pointer target type drivers/atm/ambassador.c: In function 'do_loader_command': drivers/atm/ambassador.c:1747:58: error: passing argument 1 of 'virt_to_bus' discards 'volatile' qualifier from pointer target type Declare the parameter of virt_to_phys and virt_to_bus as pointer to volatile to fix the problem. Signed-off-by: Guenter Roeck <linux@roeck-us.net> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-16Merge tag 'for-5.15/parisc-4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux Pull parisc fix from Helge Deller: "Fix a build warning when using the PAGE0 pointer" * tag 'for-5.15/parisc-4' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux: parisc: Use absolute_pointer() to define PAGE0
2021-09-16Merge tag 'm68k-for-v5.15-tag2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k Pull m68k fixes from Geert Uytterhoeven: - Warning fixes to mitigate CONFIG_WERROR=y * tag 'm68k-for-v5.15-tag2' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k: m68k: mvme: Remove overdue #warnings in RTC handling m68k: Double cast io functions to unsigned long
2021-09-16arm64: Mark __stack_chk_guard as __ro_after_initDan Li
__stack_chk_guard is setup once while init stage and never changed after that. Although the modification of this variable at runtime will usually cause the kernel to crash (so does the attacker), it should be marked as __ro_after_init, and it should not affect performance if it is placed in the ro_after_init section. Signed-off-by: Dan Li <ashimida@linux.alibaba.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/1631612642-102881-1-git-send-email-ashimida@linux.alibaba.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-09-16arm64/kernel: remove duplicate include in process.cLv Ruyi
Remove all but the first include of linux/sched.h from process.c Reported-by: Zeal Robot <zealci@zte.com.cn> Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20210902011126.29828-1-lv.ruyi@zte.com.cn Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-09-16arm64/sve: Use correct size when reinitialising SVE stateMark Brown
When we need a buffer for SVE register state we call sve_alloc() to make sure that one is there. In order to avoid repeated allocations and frees we keep the buffer around unless we change vector length and just memset() it to ensure a clean register state. The function that deals with this takes the task to operate on as an argument, however in the case where we do a memset() we initialise using the SVE state size for the current task rather than the task passed as an argument. This is only an issue in the case where we are setting the register state for a task via ptrace and the task being configured has a different vector length to the task tracing it. In the case where the buffer is larger in the traced process we will leak old state from the traced process to itself, in the case where the buffer is smaller in the traced process we will overflow the buffer and corrupt memory. Fixes: bc0ee4760364 ("arm64/sve: Core task context handling") Cc: <stable@vger.kernel.org> # 4.15.x Signed-off-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20210909165356.10675-1-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-09-16parisc: Use absolute_pointer() to define PAGE0Helge Deller
Use absolute_pointer() wrapper for PAGE0 to avoid this compiler warning: arch/parisc/kernel/setup.c: In function 'start_parisc': error: '__builtin_memcmp_eq' specified bound 8 exceeds source size 0 Signed-off-by: Helge Deller <deller@gmx.de> Co-Developed-by: Guenter Roeck <linux@roeck-us.net> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-15Merge tag 'hyperv-fixes-signed-20210915' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux Pull hyperv fixes from Wei Liu: - Fix kernel crash caused by uio driver (Vitaly Kuznetsov) - Remove on-stack cpumask from HV APIC code (Wei Liu) * tag 'hyperv-fixes-signed-20210915' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: x86/hyperv: remove on-stack cpumask from hv_send_ipi_mask_allbutself asm-generic/hyperv: provide cpumask_to_vpset_noself Drivers: hv: vmbus: Fix kernel crash upon unbinding a device from uio_hv_generic driver
2021-09-15sparc: avoid stringop-overread errorsLinus Torvalds
The sparc mdesc code does pointer games with 'struct mdesc_hdr', but didn't describe to the compiler how that header is then followed by the data that the header describes. As a result, gcc is now unhappy since it does stricter pointer range tracking, and doesn't understand about how these things work. This results in various errors like: arch/sparc/kernel/mdesc.c: In function ‘mdesc_node_by_name’: arch/sparc/kernel/mdesc.c:647:22: error: ‘strcmp’ reading 1 or more bytes from a region of size 0 [-Werror=stringop-overread] 647 | if (!strcmp(names + ep[ret].name_offset, name)) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ which are easily avoided by just describing 'struct mdesc_hdr' better, and making the node_block() helper function look into that unsized data[] that follows the header. This makes the sparc64 build happy again at least for my cross-compiler version (gcc version 11.2.1). Link: https://lore.kernel.org/lkml/CAHk-=wi4NW3NC0xWykkw=6LnjQD6D_rtRtxY9g8gQAJXtQMi8A@mail.gmail.com/ Cc: Guenter Roeck <linux@roeck-us.net> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-15Merge branch 'absolute-pointer' (patches from Guenter)Linus Torvalds
Merge absolute_pointer macro series from Guenter Roeck: "Kernel test builds currently fail for several architectures with error messages such as the following. drivers/net/ethernet/i825xx/82596.c: In function 'i82596_probe': arch/m68k/include/asm/string.h:72:25: error: '__builtin_memcpy' reading 6 bytes from a region of size 0 [-Werror=stringop-overread] Such warnings may be reported by gcc 11.x for string and memory operations on fixed addresses if gcc's builtin functions are used for those operations. This series introduces absolute_pointer() to fix the problem. absolute_pointer() disassociates a pointer from its originating symbol type and context, and thus prevents gcc from making assumptions about pointers passed to memory operations" * emailed patches from Guenter Roeck <linux@roeck-us.net>: alpha: Use absolute_pointer to define COMMAND_LINE alpha: Move setup.h out of uapi net: i825xx: Use absolute_pointer for memcpy from fixed memory location compiler.h: Introduce absolute_pointer macro
2021-09-15alpha: Use absolute_pointer to define COMMAND_LINEGuenter Roeck
alpha:allmodconfig fails to build with the following error when using gcc 11.x. arch/alpha/kernel/setup.c: In function 'setup_arch': arch/alpha/kernel/setup.c:493:13: error: 'strcmp' reading 1 or more bytes from a region of size 0 Avoid the problem by declaring COMMAND_LINE as absolute_pointer(). Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-15alpha: Move setup.h out of uapiGuenter Roeck
Most of the contents of setup.h have no value for userspace applications. The file was probably moved to uapi accidentally. Keep the file in uapi to define the alpha-specific COMMAND_LINE_SIZE. Move all other defines to arch/alpha/include/asm/setup.h. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-15s390: remove WARN_DYNAMIC_STACKHeiko Carstens
s390 is the only architecture which allows to set the -mwarn-dynamicstack compile option. This however will also always generate a warning with system call stack randomization, which uses alloca to generate some random sized stack frame. On the other hand Linus just enabled "-Werror" by default with commit 3fe617ccafd6 ("Enable '-Werror' by default for all kernel builds"), which means compiles will always fail by default. So instead of playing once again whack-a-mole for something which is s390 specific, simply remove this option. Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-09-15s390: update defconfigsHeiko Carstens
Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-09-15s390/pci_mmio: fully validate the VMA before calling follow_pte()David Hildenbrand
We should not walk/touch page tables outside of VMA boundaries when holding only the mmap sem in read mode. Evil user space can modify the VMA layout just before this function runs and e.g., trigger races with page table removal code since commit dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap"). find_vma() does not check if the address is >= the VMA start address; use vma_lookup() instead. Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Fixes: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-09-15powerpc/xics: Set the IRQ chip data for the ICS native backendCédric Le Goater
The ICS native driver relies on the IRQ chip data to find the struct 'ics_native' describing the ICS controller but it was removed by commit 248af248a8f4 ("powerpc/xics: Rename the map handler in a check handler"). Revert this change to fix the Microwatt SoC platform. Fixes: 248af248a8f4 ("powerpc/xics: Rename the map handler in a check handler") Signed-off-by: Cédric Le Goater <clg@kaod.org> Tested-by: Gustavo Romero <gustavo.romero@linaro.org> Reviewed-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210913134056.3761960-1-clg@kaod.org
2021-09-15xen: fix usage of pmd_populate in mremap for pv guestsJuergen Gross
Commit 0881ace292b662 ("mm/mremap: use pmd/pud_poplulate to update page table entries") introduced a regression when running as Xen PV guest. Today pmd_populate() for Xen PV assumes that the PFN inserted is referencing a not yet used page table. In case of move_normal_pmd() this is not true, resulting in WARN splats like: [34321.304270] ------------[ cut here ]------------ [34321.304277] WARNING: CPU: 0 PID: 23628 at arch/x86/xen/multicalls.c:102 xen_mc_flush+0x176/0x1a0 [34321.304288] Modules linked in: [34321.304291] CPU: 0 PID: 23628 Comm: apt-get Not tainted 5.14.1-20210906-doflr-mac80211debug+ #1 [34321.304294] Hardware name: MSI MS-7640/890FXA-GD70 (MS-7640) , BIOS V1.8B1 09/13/2010 [34321.304296] RIP: e030:xen_mc_flush+0x176/0x1a0 [34321.304300] Code: 89 45 18 48 c1 e9 3f 48 89 ce e9 20 ff ff ff e8 60 03 00 00 66 90 5b 5d 41 5c 41 5d c3 48 c7 45 18 ea ff ff ff be 01 00 00 00 <0f> 0b 8b 55 00 48 c7 c7 10 97 aa 82 31 db 49 c7 c5 38 97 aa 82 65 [34321.304303] RSP: e02b:ffffc90000a97c90 EFLAGS: 00010002 [34321.304305] RAX: ffff88807d416398 RBX: ffff88807d416350 RCX: ffff88807d416398 [34321.304306] RDX: 0000000000000001 RSI: 0000000000000001 RDI: deadbeefdeadf00d [34321.304308] RBP: ffff88807d416300 R08: aaaaaaaaaaaaaaaa R09: ffff888006160cc0 [34321.304309] R10: deadbeefdeadf00d R11: ffffea000026a600 R12: 0000000000000000 [34321.304310] R13: ffff888012f6b000 R14: 0000000012f6b000 R15: 0000000000000001 [34321.304320] FS: 00007f5071177800(0000) GS:ffff88807d400000(0000) knlGS:0000000000000000 [34321.304322] CS: 10000e030 DS: 0000 ES: 0000 CR0: 0000000080050033 [34321.304323] CR2: 00007f506f542000 CR3: 00000000160cc000 CR4: 0000000000000660 [34321.304326] Call Trace: [34321.304331] xen_alloc_pte+0x294/0x320 [34321.304334] move_pgt_entry+0x165/0x4b0 [34321.304339] move_page_tables+0x6fa/0x8d0 [34321.304342] move_vma.isra.44+0x138/0x500 [34321.304345] __x64_sys_mremap+0x296/0x410 [34321.304348] do_syscall_64+0x3a/0x80 [34321.304352] entry_SYSCALL_64_after_hwframe+0x44/0xae [34321.304355] RIP: 0033:0x7f507196301a [34321.304358] Code: 73 01 c3 48 8b 0d 76 0e 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 19 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 46 0e 0c 00 f7 d8 64 89 01 48 [34321.304360] RSP: 002b:00007ffda1eecd38 EFLAGS: 00000246 ORIG_RAX: 0000000000000019 [34321.304362] RAX: ffffffffffffffda RBX: 000056205f950f30 RCX: 00007f507196301a [34321.304363] RDX: 0000000001a00000 RSI: 0000000001900000 RDI: 00007f506dc56000 [34321.304364] RBP: 0000000001a00000 R08: 0000000000000010 R09: 0000000000000004 [34321.304365] R10: 0000000000000001 R11: 0000000000000246 R12: 00007f506dc56060 [34321.304367] R13: 00007f506dc56000 R14: 00007f506dc56060 R15: 000056205f950f30 [34321.304368] ---[ end trace a19885b78fe8f33e ]--- [34321.304370] 1 of 2 multicall(s) failed: cpu 0 [34321.304371] call 2: op=12297829382473034410 arg=[aaaaaaaaaaaaaaaa] result=-22 Fix that by modifying xen_alloc_ptpage() to only pin the page table in case it wasn't pinned already. Fixes: 0881ace292b662 ("mm/mremap: use pmd/pud_poplulate to update page table entries") Cc: <stable@vger.kernel.org> Reported-by: Sander Eikelenboom <linux@eikelenboom.it> Tested-by: Sander Eikelenboom <linux@eikelenboom.it> Signed-off-by: Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/20210908073640.11299-1-jgross@suse.com Signed-off-by: Juergen Gross <jgross@suse.com>
2021-09-15xen: reset legacy rtc flag for PV domUJuergen Gross
A Xen PV guest doesn't have a legacy RTC device, so reset the legacy RTC flag. Otherwise the following WARN splat will occur at boot: [ 1.333404] WARNING: CPU: 1 PID: 1 at /home/gross/linux/head/drivers/rtc/rtc-mc146818-lib.c:25 mc146818_get_time+0x1be/0x210 [ 1.333404] Modules linked in: [ 1.333404] CPU: 1 PID: 1 Comm: swapper/0 Tainted: G W 5.14.0-rc7-default+ #282 [ 1.333404] RIP: e030:mc146818_get_time+0x1be/0x210 [ 1.333404] Code: c0 64 01 c5 83 fd 45 89 6b 14 7f 06 83 c5 64 89 6b 14 41 83 ec 01 b8 02 00 00 00 44 89 63 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3 <0f> 0b 48 c7 c7 30 0e ef 82 4c 89 e6 e8 71 2a 24 00 48 c7 c0 ff ff [ 1.333404] RSP: e02b:ffffc90040093df8 EFLAGS: 00010002 [ 1.333404] RAX: 00000000000000ff RBX: ffffc90040093e34 RCX: 0000000000000000 [ 1.333404] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000000000000000d [ 1.333404] RBP: ffffffff82ef0e30 R08: ffff888005013e60 R09: 0000000000000000 [ 1.333404] R10: ffffffff82373e9b R11: 0000000000033080 R12: 0000000000000200 [ 1.333404] R13: 0000000000000000 R14: 0000000000000002 R15: ffffffff82cdc6d4 [ 1.333404] FS: 0000000000000000(0000) GS:ffff88807d440000(0000) knlGS:0000000000000000 [ 1.333404] CS: 10000e030 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1.333404] CR2: 0000000000000000 CR3: 000000000260a000 CR4: 0000000000050660 [ 1.333404] Call Trace: [ 1.333404] ? wakeup_sources_sysfs_init+0x30/0x30 [ 1.333404] ? rdinit_setup+0x2b/0x2b [ 1.333404] early_resume_init+0x23/0xa4 [ 1.333404] ? cn_proc_init+0x36/0x36 [ 1.333404] do_one_initcall+0x3e/0x200 [ 1.333404] kernel_init_freeable+0x232/0x28e [ 1.333404] ? rest_init+0xd0/0xd0 [ 1.333404] kernel_init+0x16/0x120 [ 1.333404] ret_from_fork+0x1f/0x30 Cc: <stable@vger.kernel.org> Fixes: 8d152e7a5c7537 ("x86/rtc: Replace paravirt rtc check with platform legacy quirk") Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/20210903084937.19392-3-jgross@suse.com Signed-off-by: Juergen Gross <jgross@suse.com>
2021-09-14memblock: introduce saner 'memblock_free_ptr()' interfaceLinus Torvalds
The boot-time allocation interface for memblock is a mess, with 'memblock_alloc()' returning a virtual pointer, but then you are supposed to free it with 'memblock_free()' that takes a _physical_ address. Not only is that all kinds of strange and illogical, but it actually causes bugs, when people then use it like a normal allocation function, and it fails spectacularly on a NULL pointer: https://lore.kernel.org/all/20210912140820.GD25450@xsang-OptiPlex-9020/ or just random memory corruption if the debug checks don't catch it: https://lore.kernel.org/all/61ab2d0c-3313-aaab-514c-e15b7aa054a0@suse.cz/ I really don't want to apply patches that treat the symptoms, when the fundamental cause is this horribly confusing interface. I started out looking at just automating a sane replacement sequence, but because of this mix or virtual and physical addresses, and because people have used the "__pa()" macro that can take either a regular kernel pointer, or just the raw "unsigned long" address, it's all quite messy. So this just introduces a new saner interface for freeing a virtual address that was allocated using 'memblock_alloc()', and that was kept as a regular kernel pointer. And then it converts a couple of users that are obvious and easy to test, including the 'xbc_nodes' case in lib/bootconfig.c that caused problems. Reported-by: kernel test robot <oliver.sang@intel.com> Fixes: 40caa127f3c7 ("init: bootconfig: Remove all bootconfig data when the init memory is removed") Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-14powerpc/boot: Fix build failure since GCC 4.9 removalMichael Ellerman
Stephen reported that the build was broken since commit 6d2ef226f2f1 ("compiler_attributes.h: drop __has_attribute() support for gcc4"), with errors such as: include/linux/compiler_attributes.h:296:5: warning: "__has_attribute" is not defined, evaluates to 0 [-Wundef] 296 | #if __has_attribute(__warning__) | ^~~~~~~~~~~~~~~ make[2]: *** [arch/powerpc/boot/Makefile:225: arch/powerpc/boot/crt0.o] Error 1 But we expect __has_attribute() to always be defined now that we've stopped using GCC 4. Linus debugged it to the point of reading the GCC sources, and noticing that the problem is that __has_attribute() is not defined when preprocessing assembly files, which is what we're doing here. Our assembly files don't include, or need, compiler_attributes.h, but they are getting it unconditionally from the -include in BOOT_CFLAGS, which is then added in its entirety to BOOT_AFLAGS. That -include was added in commit 77433830ed16 ("powerpc: boot: include compiler_attributes.h") so that we'd have "fallthrough" and other attributes defined for the C files in arch/powerpc/boot. But it's not needed for assembly files. The minimal fix is to move the addition to BOOT_CFLAGS of -include compiler_attributes.h until after we've copied BOOT_CFLAGS into BOOT_AFLAGS. That avoids including compiler_attributes.h for asm files, but makes no other change to BOOT_CFLAGS or BOOT_AFLAGS. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Debugged-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-14sparc32: page align size in arch_dma_allocAndreas Larsson
Commit 53b7670e5735 ("sparc: factor the dma coherent mapping into helper") lost the page align for the calls to dma_make_coherent and srmmu_unmapiorange. The latter cannot handle a non page aligned len argument. Signed-off-by: Andreas Larsson <andreas@gaisler.com> Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Christoph Hellwig <hch@lst.de>
2021-09-14x86/mce: Avoid infinite loop for copy from user recoveryTony Luck
There are two cases for machine check recovery: 1) The machine check was triggered by ring3 (application) code. This is the simpler case. The machine check handler simply queues work to be executed on return to user. That code unmaps the page from all users and arranges to send a SIGBUS to the task that triggered the poison. 2) The machine check was triggered in kernel code that is covered by an exception table entry. In this case the machine check handler still queues a work entry to unmap the page, etc. but this will not be called right away because the #MC handler returns to the fix up code address in the exception table entry. Problems occur if the kernel triggers another machine check before the return to user processes the first queued work item. Specifically, the work is queued using the ->mce_kill_me callback structure in the task struct for the current thread. Attempting to queue a second work item using this same callback results in a loop in the linked list of work functions to call. So when the kernel does return to user, it enters an infinite loop processing the same entry for ever. There are some legitimate scenarios where the kernel may take a second machine check before returning to the user. 1) Some code (e.g. futex) first tries a get_user() with page faults disabled. If this fails, the code retries with page faults enabled expecting that this will resolve the page fault. 2) Copy from user code retries a copy in byte-at-time mode to check whether any additional bytes can be copied. On the other side of the fence are some bad drivers that do not check the return value from individual get_user() calls and may access multiple user addresses without noticing that some/all calls have failed. Fix by adding a counter (current->mce_count) to keep track of repeated machine checks before task_work() is called. First machine check saves the address information and calls task_work_add(). Subsequent machine checks before that task_work call back is executed check that the address is in the same page as the first machine check (since the callback will offline exactly one page). Expected worst case is four machine checks before moving on (e.g. one user access with page faults disabled, then a repeat to the same address with page faults enabled ... repeat in copy tail bytes). Just in case there is some code that loops forever enforce a limit of 10. [ bp: Massage commit message, drop noinstr, fix typo, extend panic messages. ] Fixes: 5567d11c21a1 ("x86/mce: Send #MC singal from task work") Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/YT/IJ9ziLqmtqEPu@agluck-desk2.amr.corp.intel.com
2021-09-13Merge branch 'gcc-min-version-5.1' (make gcc-5.1 the minimum version)Linus Torvalds
Merge patch series from Nick Desaulniers to update the minimum gcc version to 5.1. This is some of the left-overs from the merge window that I didn't want to deal with yesterday, so it comes in after -rc1 but was sent before. Gcc-4.9 support has been an annoyance for some time, and with -Werror I had the choice of applying a fairly big patch from Kees Cook to remove a fair number of initializer warnings (still leaving some), or this patch series from Nick that just removes the source of the problem. The initializer cleanups might still be worth it regardless, but honestly, I preferred just tackling the problem with gcc-4.9 head-on. We've been more aggressiuve about no longer having to care about compilers that were released a long time ago, and I think it's been a good thing. I added a couple of patches on top to sort out a few left-overs now that we no longer support gcc-4.x. As noted by Arnd, as a result of this minimum compiler version upgrade we can probably change our use of '--std=gnu89' to '--std=gnu11', and finally start using local loop declarations etc. But this series does _not_ yet do that. Link: https://lore.kernel.org/all/20210909182525.372ee687@canb.auug.org.au/ Link: https://lore.kernel.org/lkml/CAK7LNASs6dvU6D3jL2GG3jW58fXfaj6VNOe55NJnTB8UPuk2pA@mail.gmail.com/ Link: https://github.com/ClangBuiltLinux/linux/issues/1438 * emailed patches from Nick Desaulniers <ndesaulniers@google.com>: Drop some straggling mentions of gcc-4.9 as being stale compiler_attributes.h: drop __has_attribute() support for gcc4 vmlinux.lds.h: remove old check for GCC 4.9 compiler-gcc.h: drop checks for older GCC versions Makefile: drop GCC < 5 -fno-var-tracking-assignments workaround arm64: remove GCC version check for ARCH_SUPPORTS_INT128 powerpc: remove GCC version check for UPD_CONSTR riscv: remove Kconfig check for GCC version for ARCH_RV64I Kconfig.debug: drop GCC 5+ version check for DWARF5 mm/ksm: remove old GCC 4.9+ check compiler.h: drop fallback overflow checkers Documentation: raise minimum supported version of GCC to 5.1
2021-09-13arm64: remove GCC version check for ARCH_SUPPORTS_INT128Nick Desaulniers
Now that GCC 5.1 is the minimally supported compiler version, this Kconfig check is no longer necessary. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-13powerpc: remove GCC version check for UPD_CONSTRNick Desaulniers
Now that GCC 5.1 is the minimum supported version, we can drop this workaround for older versions of GCC. This adversely affected clang, too. Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Segher Boessenkool <segher@kernel.crashing.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>