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2021-03-23x86/mem_encrypt: Correct physical address calculation in __set_clr_pte_enc()Isaku Yamahata1-1/+1
The pfn variable contains the page frame number as returned by the pXX_pfn() functions, shifted to the right by PAGE_SHIFT to remove the page bits. After page protection computations are done to it, it gets shifted back to the physical address using page_level_shift(). That is wrong, of course, because that function determines the shift length based on the level of the page in the page table but in all the cases, it was shifted by PAGE_SHIFT before. Therefore, shift it back using PAGE_SHIFT to get the correct physical address. [ bp: Rewrite commit message. ] Fixes: dfaaec9033b8 ("x86: Add support for changing memory encryption attribute in early boot") Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/81abbae1657053eccc535c16151f63cd049dcb97.1616098294.git.isaku.yamahata@intel.com
2021-02-26x86: fix seq_file iteration for pat/memtype.cNeilBrown1-2/+2
The memtype seq_file iterator allocates a buffer in the ->start and ->next functions and frees it in the ->show function. The preferred handling for such resources is to free them in the subsequent ->next or ->stop function call. Since Commit 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface") there is no guarantee that ->show will be called after ->next, so this function can now leak memory. So move the freeing of the buffer to ->next and ->stop. Link: https://lkml.kernel.org/r/161248539022.21478.13874455485854739066.stgit@noble1 Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface") Signed-off-by: NeilBrown <neilb@suse.de> Cc: Xin Long <lucien.xin@gmail.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Vlad Yasevich <vyasevich@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-26kfence: add test suiteMarco Elver1-1/+2
Add KFENCE test suite, testing various error detection scenarios. Makes use of KUnit for test organization. Since KFENCE's interface to obtain error reports is via the console, the test verifies that KFENCE outputs expected reports to the console. [elver@google.com: fix typo in test] Link: https://lkml.kernel.org/r/X9lHQExmHGvETxY4@elver.google.com [elver@google.com: show access type in report] Link: https://lkml.kernel.org/r/20210111091544.3287013-2-elver@google.com Link: https://lkml.kernel.org/r/20201103175841.3495947-9-elver@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Signed-off-by: Marco Elver <elver@google.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Co-developed-by: Alexander Potapenko <glider@google.com> Reviewed-by: Jann Horn <jannh@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christopher Lameter <cl@linux.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hillf Danton <hdanton@sina.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joern Engel <joern@purestorage.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: SeongJae Park <sjpark@amazon.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-26kfence: use pt_regs to generate stack trace on faultsMarco Elver1-1/+1
Instead of removing the fault handling portion of the stack trace based on the fault handler's name, just use struct pt_regs directly. Change kfence_handle_page_fault() to take a struct pt_regs, and plumb it through to kfence_report_error() for out-of-bounds, use-after-free, or invalid access errors, where pt_regs is used to generate the stack trace. If the kernel is a DEBUG_KERNEL, also show registers for more information. Link: https://lkml.kernel.org/r/20201105092133.2075331-1-elver@google.com Signed-off-by: Marco Elver <elver@google.com> Suggested-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Jann Horn <jannh@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-26x86, kfence: enable KFENCE for x86Alexander Potapenko1-0/+5
Add architecture specific implementation details for KFENCE and enable KFENCE for the x86 architecture. In particular, this implements the required interface in <asm/kfence.h> for setting up the pool and providing helper functions for protecting and unprotecting pages. For x86, we need to ensure that the pool uses 4K pages, which is done using the set_memory_4k() helper function. [elver@google.com: add missing copyright and description header] Link: https://lkml.kernel.org/r/20210118092159.145934-2-elver@google.com Link: https://lkml.kernel.org/r/20201103175841.3495947-3-elver@google.com Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Alexander Potapenko <glider@google.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Co-developed-by: Marco Elver <elver@google.com> Reviewed-by: Jann Horn <jannh@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christopher Lameter <cl@linux.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hillf Danton <hdanton@sina.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joern Engel <joern@purestorage.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: SeongJae Park <sjpark@amazon.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-20Merge tag 'x86_mm_for_v5.12' of ↵Linus Torvalds3-199/+225
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 mm cleanups from Borislav Petkov: - PTRACE_GETREGS/PTRACE_PUTREGS regset selection cleanup - Another initial cleanup - more to follow - to the fault handling code. - Other minor cleanups and corrections. * tag 'x86_mm_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits) x86/{fault,efi}: Fix and rename efi_recover_from_page_fault() x86/fault: Don't run fixups for SMAP violations x86/fault: Don't look for extable entries for SMEP violations x86/fault: Rename no_context() to kernelmode_fixup_or_oops() x86/fault: Bypass no_context() for implicit kernel faults from usermode x86/fault: Split the OOPS code out from no_context() x86/fault: Improve kernel-executing-user-memory handling x86/fault: Correct a few user vs kernel checks wrt WRUSS x86/fault: Document the locking in the fault_signal_pending() path x86/fault/32: Move is_f00f_bug() to do_kern_addr_fault() x86/fault: Fold mm_fault_error() into do_user_addr_fault() x86/fault: Skip the AMD erratum #91 workaround on unaffected CPUs x86/fault: Fix AMD erratum #91 errata fixup for user code x86/Kconfig: Remove HPET_EMULATE_RTC depends on RTC x86/asm: Fixup TASK_SIZE_MAX comment x86/ptrace: Clean up PTRACE_GETREGS/PTRACE_PUTREGS regset selection x86/vm86/32: Remove VM86_SCREEN_BITMAP support x86: Remove definition of DEBUG x86/entry: Remove now unused do_IRQ() declaration x86/mm: Remove duplicate definition of _PAGE_PAT_LARGE ...
2021-02-20Merge tag 'x86_seves_for_v5.12' of ↵Linus Torvalds1-2/+3
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 SEV-ES fix from Borislav Petkov: "Do not unroll string I/O for SEV-ES guests because they support it" * tag 'x86_seves_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/sev-es: Do not unroll string I/O for SEV-ES guests
2021-02-12Merge branch 'x86/cleanups' into x86/mmIngo Molnar2-32/+0
Merge recent cleanups to the x86 MM code to resolve a conflict. Conflicts: arch/x86/mm/fault.c Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-02-10x86/{fault,efi}: Fix and rename efi_recover_from_page_fault()Andy Lutomirski1-5/+6
efi_recover_from_page_fault() doesn't recover -- it does a special EFI mini-oops. Rename it to make it clear that it crashes. While renaming it, I noticed a blatant bug: a page fault oops in a different thread happening concurrently with an EFI runtime service call would be misinterpreted as an EFI page fault. Fix that. This isn't quite exact. The situation could be improved by using a special CS for calls into EFI. [ bp: Massage commit message and simplify in interrupt check. ] Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/f43b1e80830dc78ed60ed8b0826f4f189254570c.1612924255.git.luto@kernel.org
2021-02-10x86/fault: Don't run fixups for SMAP violationsAndy Lutomirski1-3/+6
A SMAP-violating kernel access is not a recoverable condition. Imagine kernel code that, outside of a uaccess region, dereferences a pointer to the user range by accident. If SMAP is on, this will reliably generate as an intentional user access. This makes it easy for bugs to be overlooked if code is inadequately tested both with and without SMAP. This was discovered because BPF can generate invalid accesses to user memory, but those warnings only got printed if SMAP was off. Make it so that this type of error will be discovered with SMAP on as well. [ bp: Massage commit message. ] Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/66a02343624b1ff46f02a838c497fc05c1a871b3.1612924255.git.luto@kernel.org
2021-02-10x86/fault: Don't look for extable entries for SMEP violationsAndy Lutomirski1-2/+2
If the kernel gets a SMEP violation or a fault that would have been a SMEP violation if it had SMEP support, it shouldn't run fixups. Just OOPS. [ bp: Massage commit message. ] Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/46160d8babce2abf1d6daa052146002efa24ac56.1612924255.git.luto@kernel.org
2021-02-10x86/fault: Rename no_context() to kernelmode_fixup_or_oops()Andy Lutomirski1-18/+10
The name no_context() has never been very clear. It's only called for faults from kernel mode, so rename it and change the no-longer-useful user_mode(regs) check to a WARN_ON_ONCE. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/c21940efe676024bb4bc721f7d70c29c420e127e.1612924255.git.luto@kernel.org
2021-02-10x86/fault: Bypass no_context() for implicit kernel faults from usermodeAndy Lutomirski1-27/+32
Drop an indentation level and remove the last user_mode(regs) == true caller of no_context() by directly OOPSing for implicit kernel faults from usermode. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/6e3d1129494a8de1e59d28012286e3a292a2296e.1612924255.git.luto@kernel.org
2021-02-10x86/fault: Split the OOPS code out from no_context()Andy Lutomirski1-54/+62
Not all callers of no_context() want to run exception fixups. Separate the OOPS code out from the fixup code in no_context(). Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/450f8d8eabafb83a5df349108c8e5ea83a2f939d.1612924255.git.luto@kernel.org
2021-02-10x86/fault: Improve kernel-executing-user-memory handlingAndy Lutomirski1-3/+18
Right now, the case of the kernel trying to execute from user memory is treated more or less just like the kernel getting a page fault on a user access. In the failure path, it checks for erratum #93, tries to otherwise fix up the error, and then oopses. If it manages to jump to the user address space, with or without SMEP, it should not try to resolve the page fault. This is an error, pure and simple. Rearrange the code so that this case is caught early, check for erratum #93, and bail out. [ bp: Massage commit message. ] Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/ab8719c7afb8bd501c4eee0e36493150fbbe5f6a.1612924255.git.luto@kernel.org
2021-02-10x86/fault: Correct a few user vs kernel checks wrt WRUSSAndy Lutomirski1-4/+11
In general, page fault errors for WRUSS should be just like get_user(), etc. Fix three bugs in this area: There is a comment that says that, if the kernel can't handle a page fault on a user address due to OOM, the OOM-kill-and-retry logic would be skipped. The code checked kernel *privilege*, not kernel mode, so it missed WRUSS. This means that the kernel would malfunction if it got OOM on a WRUSS fault -- this would be a kernel-mode, user-privilege fault, and the OOM killer would be invoked and the handler would retry the faulting instruction. A failed user access from kernel while a fatal signal is pending should fail even if the instruction in question was WRUSS. do_sigbus() should not send SIGBUS for WRUSS -- it should handle it like any other kernel mode failure. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/a7b7bcea730bd4069e6b7e629236bb2cf526c2fb.1612924255.git.luto@kernel.org
2021-02-10x86/fault: Document the locking in the fault_signal_pending() pathAndy Lutomirski1-1/+4
If fault_signal_pending() returns true, then the core mm has unlocked the mm for us. Add a comment to help future readers of this code. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/c56de3d103f40e6304437b150aa7b215530d23f7.1612924255.git.luto@kernel.org
2021-02-10x86/fault/32: Move is_f00f_bug() to do_kern_addr_fault()Andy Lutomirski1-5/+7
bad_area() and its relatives are called from many places in fault.c, and exactly one of them wants the F00F workaround. __bad_area_nosemaphore() no longer contains any kernel fault code, which prepares for further cleanups. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/e9668729a48ce6754022b0a4415631e8ebdd00e7.1612924255.git.luto@kernel.org
2021-02-10x86/fault: Fold mm_fault_error() into do_user_addr_fault()Andy Lutomirski1-52/+45
mm_fault_error() is logically just the end of do_user_addr_fault(). Combine the functions. This makes the code easier to read. Most of the churn here is from renaming hw_error_code to error_code in do_user_addr_fault(). This makes no difference at all to the generated code (objdump -dr) as compared to changing noinline to __always_inline in the definition of mm_fault_error(). Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/dedc4d9c9b047e51ce38b991bd23971a28af4e7b.1612924255.git.luto@kernel.org
2021-02-10x86/fault: Skip the AMD erratum #91 workaround on unaffected CPUsAndy Lutomirski1-0/+13
According to the Revision Guide for AMD Athlon™ 64 and AMD Opteron™ Processors, only early revisions of family 0xF are affected. This will avoid unnecessarily fetching instruction bytes before sending SIGSEGV to user programs. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/477173b7784bc28afb3e53d76ae5ef143917e8dd.1612924255.git.luto@kernel.org
2021-02-10x86/fault: Fix AMD erratum #91 errata fixup for user codeAndy Lutomirski1-10/+17
The recent rework of probe_kernel_address() and its conversion to get_kernel_nofault() inadvertently broke is_prefetch(). Before this change, probe_kernel_address() was used as a sloppy "read user or kernel memory" helper, but it doesn't do that any more. The new get_kernel_nofault() reads *kernel* memory only, which completely broke is_prefetch() for user access. Adjust the code to the correct accessor based on access mode. The manual address bounds check is no longer necessary, since the accessor helpers (get_user() / get_kernel_nofault()) do the right thing all by themselves. As a bonus, by using the correct accessor, the open-coded address bounds check is not needed anymore. [ bp: Massage commit message. ] Fixes: eab0c6089b68 ("maccess: unify the probe kernel arch hooks") Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/b91f7f92f3367d2d3a88eec3b09c6aab1b2dc8ef.1612924255.git.luto@kernel.org
2021-02-03KVM: SVM: Treat SVM as unsupported when running as an SEV guestSean Christopherson1-0/+1
Don't let KVM load when running as an SEV guest, regardless of what CPUID says. Memory is encrypted with a key that is not accessible to the host (L0), thus it's impossible for L0 to emulate SVM, e.g. it'll see garbage when reading the VMCB. Technically, KVM could decrypt all memory that needs to be accessible to the L0 and use shadow paging so that L0 does not need to shadow NPT, but exposing such information to L0 largely defeats the purpose of running as an SEV guest. This can always be revisited if someone comes up with a use case for running VMs inside SEV guests. Note, VMLOAD, VMRUN, etc... will also #GP on GPAs with C-bit set, i.e. KVM is doomed even if the SEV guest is debuggable and the hypervisor is willing to decrypt the VMCB. This may or may not be fixed on CPUs that have the SVME_ADDR_CHK fix. Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210202212017.2486595-1-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-02x86/sev-es: Do not unroll string I/O for SEV-ES guestsTom Lendacky1-2/+3
Under the GHCB specification, SEV-ES guests can support string I/O. The current #VC handler contains this support, so remove the need to unroll kernel string I/O operations. This will reduce the number of #VC exceptions generated as well as the number VM exits for the guest. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/3de04b5b638546ac75d42ba52307fe1a922173d3.1612203987.git.thomas.lendacky@amd.com
2021-01-21x86/vm86/32: Remove VM86_SCREEN_BITMAP supportAndy Lutomirski1-30/+0
The implementation was rather buggy. It unconditionally marked PTEs read-only, even for VM_SHARED mappings. I'm not sure whether this is actually a problem, but it certainly seems unwise. More importantly, it released the mmap lock before flushing the TLB, which could allow a racing CoW operation to falsely believe that the underlying memory was not writable. I can't find any users at all of this mechanism, so just remove it. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Stas Sergeev <stsp2@yandex.ru> Link: https://lkml.kernel.org/r/f3086de0babcab36f69949b5780bde851f719bc8.1611078018.git.luto@kernel.org
2021-01-15x86: Remove definition of DEBUGTom Rix1-2/+0
Defining DEBUG should only be done in development. So remove it. Signed-off-by: Tom Rix <trix@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Link: https://lkml.kernel.org/r/20210114212827.47584-1-trix@redhat.com
2021-01-05x86/mm: Fix leak of pmd ptlockDan Williams1-0/+2
Commit 28ee90fe6048 ("x86/mm: implement free pmd/pte page interfaces") introduced a new location where a pmd was released, but neglected to run the pmd page destructor. In fact, this happened previously for a different pmd release path and was fixed by commit: c283610e44ec ("x86, mm: do not leak page->ptl for pmd page tables"). This issue was hidden until recently because the failure mode is silent, but commit: b2b29d6d0119 ("mm: account PMD tables like PTE tables") turns the failure mode into this signature: BUG: Bad page state in process lt-pmem-ns pfn:15943d page:000000007262ed7b refcount:0 mapcount:-1024 mapping:0000000000000000 index:0x0 pfn:0x15943d flags: 0xaffff800000000() raw: 00affff800000000 dead000000000100 0000000000000000 0000000000000000 raw: 0000000000000000 ffff913a029bcc08 00000000fffffbff 0000000000000000 page dumped because: nonzero mapcount [..] dump_stack+0x8b/0xb0 bad_page.cold+0x63/0x94 free_pcp_prepare+0x224/0x270 free_unref_page+0x18/0xd0 pud_free_pmd_page+0x146/0x160 ioremap_pud_range+0xe3/0x350 ioremap_page_range+0x108/0x160 __ioremap_caller.constprop.0+0x174/0x2b0 ? memremap+0x7a/0x110 memremap+0x7a/0x110 devm_memremap+0x53/0xa0 pmem_attach_disk+0x4ed/0x530 [nd_pmem] ? __devm_release_region+0x52/0x80 nvdimm_bus_probe+0x85/0x210 [libnvdimm] Given this is a repeat occurrence it seemed prudent to look for other places where this destructor might be missing and whether a better helper is needed. try_to_free_pmd_page() looks like a candidate, but testing with setting up and tearing down pmd mappings via the dax unit tests is thus far not triggering the failure. As for a better helper pmd_free() is close, but it is a messy fit due to requiring an @mm arg. Also, ___pmd_free_tlb() wants to call paravirt_tlb_remove_table() instead of free_page(), so open-coded pgtable_pmd_page_dtor() seems the best way forward for now. Debugged together with Matthew Wilcox <willy@infradead.org>. Fixes: 28ee90fe6048 ("x86/mm: implement free pmd/pte page interfaces") Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Yi Zhang <yi.zhang@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/160697689204.605323.17629854984697045602.stgit@dwillia2-desk3.amr.corp.intel.com
2021-01-04x86/mm: Increase pgt_buf size for 5-level page tablesLorenzo Stoakes1-5/+14
pgt_buf is used to allocate page tables on initial direct page mapping which bootstraps the kernel into being able to allocate these before the direct mapping makes further pages available. INIT_PGD_PAGE_COUNT is set to 6 pages (doubled for KASLR) - 3 (PUD, PMD, PTE) for the 1 MiB ISA mapping and 3 more for the first direct mapping assignment in each case providing 2 MiB of address space. This has not been updated for 5-level page tables which has an additional P4D page table level above PUD. In most instances, this will not have a material impact as the first 4 page levels allocated for the ISA mapping will provide sufficient address space to encompass all further address mappings. If the first direct mapping is within 512 GiB of the ISA mapping, only a PMD and PTE needs to be added in the instance the kernel is using 4 KiB page tables (e.g. CONFIG_DEBUG_PAGEALLOC is enabled) and only a PMD if the kernel can use 2 MiB pages (the first allocation is limited to PMD_SIZE so a GiB page cannot be used there). However, if the machine has more than 512 GiB of RAM and the kernel is allocating 4 KiB page size, 3 further page tables are required. If the machine has more than 256 TiB of RAM at 4 KiB or 2 MiB page size, further 3 or 4 page tables are required respectively. Update INIT_PGD_PAGE_COUNT to reflect this. [ bp: Sanitize text into passive voice without ambiguous personal pronouns. ] Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Dave Hansen <dave.hansen@intel.com> Link: https://lkml.kernel.org/r/20201215205641.34096-1-lstoakes@gmail.com
2020-12-16Merge branch 'stable/for-linus-5.11' of ↵Linus Torvalds1-0/+31
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb Pull swiotlb update from Konrad Rzeszutek Wilk: "A generic (but for right now engaged only with AMD SEV) mechanism to adjust a larger size SWIOTLB based on the total memory of the SEV guests which right now require the bounce buffer for interacting with the outside world. Normal knobs (swiotlb=XYZ) still work" * 'stable/for-linus-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb: x86,swiotlb: Adjust SWIOTLB bounce buffer size for SEV guests
2020-12-15Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-2/+2
Merge misc updates from Andrew Morton: - a few random little subsystems - almost all of the MM patches which are staged ahead of linux-next material. I'll trickle to post-linux-next work in as the dependents get merged up. Subsystems affected by this patch series: kthread, kbuild, ide, ntfs, ocfs2, arch, and mm (slab-generic, slab, slub, dax, debug, pagecache, gup, swap, shmem, memcg, pagemap, mremap, hmm, vmalloc, documentation, kasan, pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction, oom-kill, migration, cma, page-poison, userfaultfd, zswap, zsmalloc, uaccess, zram, and cleanups). * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (200 commits) mm: cleanup kstrto*() usage mm: fix fall-through warnings for Clang mm: slub: convert sysfs sprintf family to sysfs_emit/sysfs_emit_at mm: shmem: convert shmem_enabled_show to use sysfs_emit_at mm:backing-dev: use sysfs_emit in macro defining functions mm: huge_memory: convert remaining use of sprintf to sysfs_emit and neatening mm: use sysfs_emit for struct kobject * uses mm: fix kernel-doc markups zram: break the strict dependency from lzo zram: add stat to gather incompressible pages since zram set up zram: support page writeback mm/process_vm_access: remove redundant initialization of iov_r mm/zsmalloc.c: rework the list_add code in insert_zspage() mm/zswap: move to use crypto_acomp API for hardware acceleration mm/zswap: fix passing zero to 'PTR_ERR' warning mm/zswap: make struct kernel_param_ops definitions const userfaultfd/selftests: hint the test runner on required privilege userfaultfd/selftests: fix retval check for userfaultfd_open() userfaultfd/selftests: always dump something in modes userfaultfd: selftests: make __{s,u}64 format specifiers portable ...
2020-12-15arch, mm: make kernel_page_present() always availableMike Rapoport1-3/+1
For architectures that enable ARCH_HAS_SET_MEMORY having the ability to verify that a page is mapped in the kernel direct map can be useful regardless of hibernation. Add RISC-V implementation of kernel_page_present(), update its forward declarations and stubs to be a part of set_memory API and remove ugly ifdefery in inlcude/linux/mm.h around current declarations of kernel_page_present(). Link: https://lkml.kernel.org/r/20201109192128.960-5-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Andy Lutomirski <luto@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Len Brown <len.brown@intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15arch, mm: restore dependency of __kernel_map_pages() on DEBUG_PAGEALLOCMike Rapoport1-0/+2
The design of DEBUG_PAGEALLOC presumes that __kernel_map_pages() must never fail. With this assumption is wouldn't be safe to allow general usage of this function. Moreover, some architectures that implement __kernel_map_pages() have this function guarded by #ifdef DEBUG_PAGEALLOC and some refuse to map/unmap pages when page allocation debugging is disabled at runtime. As all the users of __kernel_map_pages() were converted to use debug_pagealloc_map_pages() it is safe to make it available only when DEBUG_PAGEALLOC is set. Link: https://lkml.kernel.org/r/20201109192128.960-4-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Andy Lutomirski <luto@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Rientjes <rientjes@google.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Len Brown <len.brown@intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-14Merge tag 'core-mm-2020-12-14' of ↵Linus Torvalds3-128/+3
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull kmap updates from Thomas Gleixner: "The new preemtible kmap_local() implementation: - Consolidate all kmap_atomic() internals into a generic implementation which builds the base for the kmap_local() API and make the kmap_atomic() interface wrappers which handle the disabling/enabling of preemption and pagefaults. - Switch the storage from per-CPU to per task and provide scheduler support for clearing mapping when scheduling out and restoring them when scheduling back in. - Merge the migrate_disable/enable() code, which is also part of the scheduler pull request. This was required to make the kmap_local() interface available which does not disable preemption when a mapping is established. It has to disable migration instead to guarantee that the virtual address of the mapped slot is the same across preemption. - Provide better debug facilities: guard pages and enforced utilization of the mapping mechanics on 64bit systems when the architecture allows it. - Provide the new kmap_local() API which can now be used to cleanup the kmap_atomic() usage sites all over the place. Most of the usage sites do not require the implicit disabling of preemption and pagefaults so the penalty on 64bit and 32bit non-highmem systems is removed and quite some of the code can be simplified. A wholesale conversion is not possible because some usage depends on the implicit side effects and some need to be cleaned up because they work around these side effects. The migrate disable side effect is only effective on highmem systems and when enforced debugging is enabled. On 64bit and 32bit non-highmem systems the overhead is completely avoided" * tag 'core-mm-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits) ARM: highmem: Fix cache_is_vivt() reference x86/crashdump/32: Simplify copy_oldmem_page() io-mapping: Provide iomap_local variant mm/highmem: Provide kmap_local* sched: highmem: Store local kmaps in task struct x86: Support kmap_local() forced debugging mm/highmem: Provide CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP mm/highmem: Provide and use CONFIG_DEBUG_KMAP_LOCAL microblaze/mm/highmem: Add dropped #ifdef back xtensa/mm/highmem: Make generic kmap_atomic() work correctly mm/highmem: Take kmap_high_get() properly into account highmem: High implementation details and document API Documentation/io-mapping: Remove outdated blurb io-mapping: Cleanup atomic iomap mm/highmem: Remove the old kmap_atomic cruft highmem: Get rid of kmap_types.h xtensa/mm/highmem: Switch to generic kmap atomic sparc/mm/highmem: Switch to generic kmap atomic powerpc/mm/highmem: Switch to generic kmap atomic nds32/mm/highmem: Switch to generic kmap atomic ...
2020-12-14Merge tag 'x86_cleanups_for_v5.11' of ↵Linus Torvalds1-2/+4
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cleanups from Borislav Petkov: "Another branch with a nicely negative diffstat, just the way I like 'em: - Remove all uses of TIF_IA32 and TIF_X32 and reclaim the two bits in the end (Gabriel Krisman Bertazi) - All kinds of minor cleanups all over the tree" * tag 'x86_cleanups_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) x86/ia32_signal: Propagate __user annotation properly x86/alternative: Update text_poke_bp() kernel-doc comment x86/PCI: Make a kernel-doc comment a normal one x86/asm: Drop unused RDPID macro x86/boot/compressed/64: Use TEST %reg,%reg instead of CMP $0,%reg x86/head64: Remove duplicate include x86/mm: Declare 'start' variable where it is used x86/head/64: Remove unused GET_CR2_INTO() macro x86/boot: Remove unused finalize_identity_maps() x86/uaccess: Document copy_from_user_nmi() x86/dumpstack: Make show_trace_log_lvl() static x86/mtrr: Fix a kernel-doc markup x86/setup: Remove unused MCA variables x86, libnvdimm/test: Remove COPY_MC_TEST x86: Reclaim TIF_IA32 and TIF_X32 x86/mm: Convert mmu context ia32_compat into a proper flags field x86/elf: Use e_machine to check for x32/ia32 in setup_additional_pages() elf: Expose ELF header on arch_setup_additional_pages() x86/elf: Use e_machine to select start_thread for x32 elf: Expose ELF header in compat_start_thread() ...
2020-12-14Merge tag 'x86_mm_for_v5.11' of ↵Linus Torvalds1-2/+10
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 mm update from Borislav Petkov: "A single improvement to check ident_pud_init()'s return value (Arvind Sankar)" * tag 'x86_mm_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm/ident_map: Check for errors from ident_pud_init()
2020-12-14Merge tag 'x86_sgx_for_v5.11' of ↵Linus Torvalds1-12/+33
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 SGC support from Borislav Petkov: "Intel Software Guard eXtensions enablement. This has been long in the making, we were one revision number short of 42. :) Intel SGX is new hardware functionality that can be used by applications to populate protected regions of user code and data called enclaves. Once activated, the new hardware protects enclave code and data from outside access and modification. Enclaves provide a place to store secrets and process data with those secrets. SGX has been used, for example, to decrypt video without exposing the decryption keys to nosy debuggers that might be used to subvert DRM. Software has generally been rewritten specifically to run in enclaves, but there are also projects that try to run limited unmodified software in enclaves. Most of the functionality is concentrated into arch/x86/kernel/cpu/sgx/ except the addition of a new mprotect() hook to control enclave page permissions and support for vDSO exceptions fixup which will is used by SGX enclaves. All this work by Sean Christopherson, Jarkko Sakkinen and many others" * tag 'x86_sgx_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (30 commits) x86/sgx: Return -EINVAL on a zero length buffer in sgx_ioc_enclave_add_pages() x86/sgx: Fix a typo in kernel-doc markup x86/sgx: Fix sgx_ioc_enclave_provision() kernel-doc comment x86/sgx: Return -ERESTARTSYS in sgx_ioc_enclave_add_pages() selftests/sgx: Use a statically generated 3072-bit RSA key x86/sgx: Clarify 'laundry_list' locking x86/sgx: Update MAINTAINERS Documentation/x86: Document SGX kernel architecture x86/sgx: Add ptrace() support for the SGX driver x86/sgx: Add a page reclaimer selftests/x86: Add a selftest for SGX x86/vdso: Implement a vDSO for Intel SGX enclave call x86/traps: Attempt to fixup exceptions in vDSO before signaling x86/fault: Add a helper function to sanitize error code x86/vdso: Add support for exception fixup in vDSO functions x86/sgx: Add SGX_IOC_ENCLAVE_PROVISION x86/sgx: Add SGX_IOC_ENCLAVE_INIT x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES x86/sgx: Add SGX_IOC_ENCLAVE_CREATE x86/sgx: Add an SGX misc driver interface ...
2020-12-11x86,swiotlb: Adjust SWIOTLB bounce buffer size for SEV guestsAshish Kalra1-0/+31
For SEV, all DMA to and from guest has to use shared (un-encrypted) pages. SEV uses SWIOTLB to make this happen without requiring changes to device drivers. However, depending on the workload being run, the default 64MB of it might not be enough and it may run out of buffers to use for DMA, resulting in I/O errors and/or performance degradation for high I/O workloads. Adjust the default size of SWIOTLB for SEV guests using a percentage of the total memory available to guest for the SWIOTLB buffers. Adds a new sev_setup_arch() function which is invoked from setup_arch() and it calls into a new swiotlb generic code function swiotlb_adjust_size() to do the SWIOTLB buffer adjustment. v5 fixed build errors and warnings as Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> Co-developed-by: Borislav Petkov <bp@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2020-12-10x86/mm/mem_encrypt: Fix definition of PMD_FLAGS_DEC_WPArvind Sankar1-2/+2
The PAT bit is in different locations for 4k and 2M/1G page table entries. Add a definition for _PAGE_LARGE_CACHE_MASK to represent the three caching bits (PWT, PCD, PAT), similar to _PAGE_CACHE_MASK for 4k pages, and use it in the definition of PMD_FLAGS_DEC_WP to get the correct PAT index for write-protected pages. Fixes: 6ebcb060713f ("x86/mm: Add support to encrypt the kernel in-place") Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Tom Lendacky <thomas.lendacky@amd.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20201111160946.147341-1-nivedita@alum.mit.edu
2020-12-09x86/membarrier: Get rid of a dubious optimizationAndy Lutomirski1-2/+8
sync_core_before_usermode() had an incorrect optimization. If the kernel returns from an interrupt, it can get to usermode without IRET. It just has to schedule to a different task in the same mm and do SYSRET. Fortunately, there were no callers of sync_core_before_usermode() that could have had in_irq() or in_nmi() equal to true, because it's only ever called from the scheduler. While at it, clarify a related comment. Fixes: 70216e18e519 ("membarrier: Provide core serializing command, *_SYNC_CORE") Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/5afc7632be1422f91eaf7611aaaa1b5b8580a086.1607058304.git.luto@kernel.org
2020-11-22mm: fix phys_to_target_node() and memory_add_physaddr_to_nid() exportsDan Williams1-0/+2
The core-mm has a default __weak implementation of phys_to_target_node() to mirror the weak definition of memory_add_physaddr_to_nid(). That symbol is exported for modules. However, while the export in mm/memory_hotplug.c exported the symbol in the configuration cases of: CONFIG_NUMA_KEEP_MEMINFO=y CONFIG_MEMORY_HOTPLUG=y ...and: CONFIG_NUMA_KEEP_MEMINFO=n CONFIG_MEMORY_HOTPLUG=y ...it failed to export the symbol in the case of: CONFIG_NUMA_KEEP_MEMINFO=y CONFIG_MEMORY_HOTPLUG=n Not only is that broken, but Christoph points out that the kernel should not be exporting any __weak symbol, which means that memory_add_physaddr_to_nid() example that phys_to_target_node() copied is broken too. Rework the definition of phys_to_target_node() and memory_add_physaddr_to_nid() to not require weak symbols. Move to the common arch override design-pattern of an asm header defining a symbol to replace the default implementation. The only common header that all memory_add_physaddr_to_nid() producing architectures implement is asm/sparsemem.h. In fact, powerpc already defines its memory_add_physaddr_to_nid() helper in sparsemem.h. Double-down on that observation and define phys_to_target_node() where necessary in asm/sparsemem.h. An alternate consideration that was discarded was to put this override in asm/numa.h, but that entangles with the definition of MAX_NUMNODES relative to the inclusion of linux/nodemask.h, and requires powerpc to grow a new header. The dependency on NUMA_KEEP_MEMINFO for DEV_DAX_HMEM_DEVICES is invalid now that the symbol is properly exported / stubbed in all combinations of CONFIG_NUMA_KEEP_MEMINFO and CONFIG_MEMORY_HOTPLUG. [dan.j.williams@intel.com: v4] Link: https://lkml.kernel.org/r/160461461867.1505359.5301571728749534585.stgit@dwillia2-desk3.amr.corp.intel.com [dan.j.williams@intel.com: powerpc: fix create_section_mapping compile warning] Link: https://lkml.kernel.org/r/160558386174.2948926.2740149041249041764.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: a035b6bf863e ("mm/memory_hotplug: introduce default phys_to_target_node() implementation") Reported-by: Randy Dunlap <rdunlap@infradead.org> Reported-by: Thomas Gleixner <tglx@linutronix.de> Reported-by: kernel test robot <lkp@intel.com> Reported-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Randy Dunlap <rdunlap@infradead.org> Tested-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Link: https://lkml.kernel.org/r/160447639846.1133764.7044090803980177548.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-20x86/mm: Declare 'start' variable where it is usedLukas Bulwahn1-2/+4
It is not required to initialize the local variable start in memory_map_top_down(), as the variable will be initialized in any path before it is used. make clang-analyzer on x86_64 tinyconfig reports: arch/x86/mm/init.c:612:15: warning: Although the value stored to 'start' \ is used in the enclosing expression, the value is never actually read \ from 'start' [clang-analyzer-deadcode.DeadStores] Move the variable declaration into the loop, where it is used. No code changed: # arch/x86/mm/init.o: text data bss dec hex filename 7105 1424 26768 35297 89e1 init.o.before 7105 1424 26768 35297 89e1 init.o.after md5: a8d76c1bb5fce9cae251780a7ee7730f init.o.before.asm a8d76c1bb5fce9cae251780a7ee7730f init.o.after.asm [ bp: Massage. ] Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lkml.kernel.org/r/20200928100004.25674-1-lukas.bulwahn@gmail.com
2020-11-18x86/traps: Attempt to fixup exceptions in vDSO before signalingSean Christopherson1-0/+7
vDSO functions can now leverage an exception fixup mechanism similar to kernel exception fixup. For vDSO exception fixup, the initial user is Intel's Software Guard Extensions (SGX), which will wrap the low-level transitions to/from the enclave, i.e. EENTER and ERESUME instructions, in a vDSO function and leverage fixup to intercept exceptions that would otherwise generate a signal. This allows the vDSO wrapper to return the fault information directly to its caller, obviating the need for SGX applications and libraries to juggle signal handlers. Attempt to fixup vDSO exceptions immediately prior to populating and sending signal information. Except for the delivery mechanism, an exception in a vDSO function should be treated like any other exception in userspace, e.g. any fault that is successfully handled by the kernel should not be directly visible to userspace. Although it's debatable whether or not all exceptions are of interest to enclaves, defer to the vDSO fixup to decide whether to do fixup or generate a signal. Future users of vDSO fixup, if there ever are any, will undoubtedly have different requirements than SGX enclaves, e.g. the fixup vs. signal logic can be made function specific if/when necessary. Suggested-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Jethro Beekman <jethro@fortanix.com> Link: https://lkml.kernel.org/r/20201112220135.165028-19-jarkko@kernel.org
2020-11-18x86/fault: Add a helper function to sanitize error codeSean Christopherson1-12/+14
vDSO exception fixup is a replacement for signals in limited situations. Signals and vDSO exception fixup need to provide similar information to userspace, including the hardware error code. That hardware error code needs to be sanitized. For instance, if userspace accesses a kernel address, the error code could indicate to userspace whether the address had a Present=1 PTE. That can leak information about the kernel layout to userspace, which is bad. The existing signal code does this sanitization, but fairly late in the signal process. The vDSO exception code runs before the sanitization happens. Move error code sanitization out of the signal code and into a helper. Call the helper in the signal code. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Jethro Beekman <jethro@fortanix.com> Link: https://lkml.kernel.org/r/20201112220135.165028-18-jarkko@kernel.org
2020-11-17x86/mm: Signal SIGSEGV with PF_SGXSean Christopherson1-0/+12
The x86 architecture has a set of page fault error codes. These indicate things like whether the fault occurred from a write, or whether it originated in userspace. The SGX hardware architecture has its own per-page memory management metadata (EPCM) [*] and hardware which is separate from the normal x86 MMU. The architecture has a new page fault error code: PF_SGX. This new error code bit is set whenever a page fault occurs as the result of the SGX MMU. These faults occur for a variety of reasons. For instance, an access attempt to enclave memory from outside the enclave causes a PF_SGX fault. PF_SGX would also be set for permission conflicts, such as if a write to an enclave page occurs and the page is marked read-write in the x86 page tables but is read-only in the EPCM. These faults do not always indicate errors, though. SGX pages are encrypted with a key that is destroyed at hardware reset, including suspend. Throwing a SIGSEGV allows user space software to react and recover when these events occur. Include PF_SGX in the PF error codes list and throw SIGSEGV when it is encountered. [*] Intel SDM: 36.5.1 Enclave Page Cache Map (EPCM) [ bp: Add bit 15 to the comment above enum x86_pf_error_code too. ] Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Jethro Beekman <jethro@fortanix.com> Link: https://lkml.kernel.org/r/20201112220135.165028-7-jarkko@kernel.org
2020-11-06io-mapping: Cleanup atomic iomapThomas Gleixner1-4/+2
Switch the atomic iomap implementation over to kmap_local and stick the preempt/pagefault mechanics into the generic code similar to the kmap_atomic variants. Rename the x86 map function in preparation for a non-atomic variant. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linuxfoundation.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Andrew Morton <akpm@linux-foundation.org> Link: https://lore.kernel.org/r/20201103095858.625310005@linutronix.de
2020-11-06x86/mm/highmem: Use generic kmap atomic implementationThomas Gleixner3-128/+5
Convert X86 to the generic kmap atomic implementation and make the iomap_atomic() naming convention consistent while at it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201103095857.375127260@linutronix.de
2020-10-29x86/head/64: Check SEV encryption before switching to kernel page-tableJoerg Roedel1-0/+1
When SEV is enabled, the kernel requests the C-bit position again from the hypervisor to build its own page-table. Since the hypervisor is an untrusted source, the C-bit position needs to be verified before the kernel page-table is used. Call sev_verify_cbit() before writing the CR3. [ bp: Massage. ] Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lkml.kernel.org/r/20201028164659.27002-5-joro@8bytes.org
2020-10-28x86/mm/ident_map: Check for errors from ident_pud_init()Arvind Sankar1-2/+10
Commit ea3b5e60ce80 ("x86/mm/ident_map: Add 5-level paging support") added ident_p4d_init() to support 5-level paging, but this function doesn't check and return errors from ident_pud_init(). For example, the decompressor stub uses this code to create an identity mapping. If it runs out of pages while trying to allocate a PMD pagetable, the error will be currently ignored. Fix this to propagate errors. [ bp: Space out statements for better readability. ] Fixes: ea3b5e60ce80 ("x86/mm/ident_map: Add 5-level paging support") Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Joerg Roedel <jroedel@suse.de> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Link: https://lkml.kernel.org/r/20201027230648.1885111-1-nivedita@alum.mit.edu
2020-10-25treewide: Convert macro and uses of __section(foo) to __section("foo")Joe Perches2-4/+4
Use a more generic form for __section that requires quotes to avoid complications with clang and gcc differences. Remove the quote operator # from compiler_attributes.h __section macro. Convert all unquoted __section(foo) uses to quoted __section("foo"). Also convert __attribute__((section("foo"))) uses to __section("foo") even if the __attribute__ has multiple list entry forms. Conversion done using the script at: https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl Signed-off-by: Joe Perches <joe@perches.com> Reviewed-by: Nick Desaulniers <ndesaulniers@gooogle.com> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-23Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds1-5/+8
Pull KVM updates from Paolo Bonzini: "For x86, there is a new alternative and (in the future) more scalable implementation of extended page tables that does not need a reverse map from guest physical addresses to host physical addresses. For now it is disabled by default because it is still lacking a few of the existing MMU's bells and whistles. However it is a very solid piece of work and it is already available for people to hammer on it. Other updates: ARM: - New page table code for both hypervisor and guest stage-2 - Introduction of a new EL2-private host context - Allow EL2 to have its own private per-CPU variables - Support of PMU event filtering - Complete rework of the Spectre mitigation PPC: - Fix for running nested guests with in-kernel IRQ chip - Fix race condition causing occasional host hard lockup - Minor cleanups and bugfixes x86: - allow trapping unknown MSRs to userspace - allow userspace to force #GP on specific MSRs - INVPCID support on AMD - nested AMD cleanup, on demand allocation of nested SVM state - hide PV MSRs and hypercalls for features not enabled in CPUID - new test for MSR_IA32_TSC writes from host and guest - cleanups: MMU, CPUID, shared MSRs - LAPIC latency optimizations ad bugfixes" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (232 commits) kvm: x86/mmu: NX largepage recovery for TDP MMU kvm: x86/mmu: Don't clear write flooding count for direct roots kvm: x86/mmu: Support MMIO in the TDP MMU kvm: x86/mmu: Support write protection for nesting in tdp MMU kvm: x86/mmu: Support disabling dirty logging for the tdp MMU kvm: x86/mmu: Support dirty logging for the TDP MMU kvm: x86/mmu: Support changed pte notifier in tdp MMU kvm: x86/mmu: Add access tracking for tdp_mmu kvm: x86/mmu: Support invalidate range MMU notifier for TDP MMU kvm: x86/mmu: Allocate struct kvm_mmu_pages for all pages in TDP MMU kvm: x86/mmu: Add TDP MMU PF handler kvm: x86/mmu: Remove disallowed_hugepage_adjust shadow_walk_iterator arg kvm: x86/mmu: Support zapping SPTEs in the TDP MMU KVM: Cache as_id in kvm_memory_slot kvm: x86/mmu: Add functions to handle changed TDP SPTEs kvm: x86/mmu: Allocate and free TDP MMU roots kvm: x86/mmu: Init / Uninit the TDP MMU kvm: x86/mmu: Introduce tdp_iter KVM: mmu: extract spte.h and spte.c KVM: mmu: Separate updating a PTE from kvm_set_pte_rmapp ...
2020-10-21x86/kvm: Update the comment about asynchronous page fault in exc_page_fault()Vitaly Kuznetsov1-5/+8
KVM was switched to interrupt-based mechanism for 'page ready' event delivery in Linux-5.8 (see commit 2635b5c4a0e4 ("KVM: x86: interrupt based APF 'page ready' event delivery")) and #PF (ab)use for 'page ready' event delivery was removed. Linux guest switched to this new mechanism exclusively in 5.9 (see commit b1d405751cd5 ("KVM: x86: Switch KVM guest to using interrupts for page ready APF delivery")) so it is not possible to get #PF for a 'page ready' event even when the guest is running on top of an older KVM (APF mechanism won't be enabled). Update the comment in exc_page_fault() to reflect the new reality. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20201002154313.1505327-1-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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