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2021-03-24x86/mce/inject: Add IPID for injection tooBorislav Petkov
Add an injection file in order to specify the IPID too when injecting an error. One use case example is using the machinery to decode MCEs collected from other machines. Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210314201806.12798-1-bp@alien8.de
2021-03-21x86: Fix various typos in comments, take #2Ingo Molnar
Fix another ~42 single-word typos in arch/x86/ code comments, missed a few in the first pass, in particular in .S files. Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: linux-kernel@vger.kernel.org
2021-03-20x86/mce: Add Xeon Sapphire Rapids to list of CPUs that support PPINTony Luck
New CPU model, same MSRs to control and read the inventory number. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20210319173919.291428-1-tony.luck@intel.com
2021-03-18x86: Fix various typos in commentsIngo Molnar
Fix ~144 single-word typos in arch/x86/ code comments. Doing this in a single commit should reduce the churn. Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: linux-kernel@vger.kernel.org
2021-03-15x86/mce: Convert to insn_decode()Borislav Petkov
Simplify code, no functional changes. Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210304174237.31945-11-bp@alien8.de
2021-02-20Merge tag 'ras_updates_for_v5.12' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RAS updates from Borislav Petkov: - move therm_throt.c to the thermal framework, where it belongs. - identify CPUs which miss to enter the broadcast handler, as an additional debugging aid. * tag 'ras_updates_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: thermal: Move therm_throt there from x86/mce x86/mce: Get rid of mcheck_intel_therm_init() x86/mce: Make mce_timed_out() identify holdout CPUs
2021-02-08thermal: Move therm_throt there from x86/mceBorislav Petkov
This functionality has nothing to do with MCE, move it to the thermal framework and untangle it from MCE. Requested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Link: https://lkml.kernel.org/r/20210202121003.GD18075@zn.tnic
2021-02-08x86/mce: Get rid of mcheck_intel_therm_init()Borislav Petkov
Move the APIC_LVTTHMR read which needs to happen on the BSP, to intel_init_thermal(). One less boot dependency. No functional changes. Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Link: https://lkml.kernel.org/r/20210201142704.12495-2-bp@alien8.de
2021-01-12x86/mce: Remove explicit/superfluous tracingPeter Zijlstra
There's some explicit tracing left in exc_machine_check_kernel(), remove it, as it's already implied by irqentry_nmi_enter(). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210106144017.719310466@infradead.org
2021-01-08x86/mce: Make mce_timed_out() identify holdout CPUsPaul E. McKenney
The "Timeout: Not all CPUs entered broadcast exception handler" message will appear from time to time given enough systems, but this message does not identify which CPUs failed to enter the broadcast exception handler. This information would be valuable if available, for example, in order to correlate with other hardware-oriented error messages. Add a cpumask of CPUs which maintains which CPUs have entered this handler, and print out which ones failed to enter in the event of a timeout. [ bp: Massage. ] Reported-by: Jonathan Lemon <bsd@fb.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lkml.kernel.org/r/20210106174102.GA23874@paulmck-ThinkPad-P72
2020-12-14Merge tag 'core-entry-2020-12-14' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull core entry/exit updates from Thomas Gleixner: "A set of updates for entry/exit handling: - More generalization of entry/exit functionality - The consolidation work to reclaim TIF flags on x86 and also for non-x86 specific TIF flags which are solely relevant for syscall related work and have been moved into their own storage space. The x86 specific part had to be merged in to avoid a major conflict. - The TIF_NOTIFY_SIGNAL work which replaces the inefficient signal delivery mode of task work and results in an impressive performance improvement for io_uring. The non-x86 consolidation of this is going to come seperate via Jens. - The selective syscall redirection facility which provides a clean and efficient way to support the non-Linux syscalls of WINE by catching them at syscall entry and redirecting them to the user space emulation. This can be utilized for other purposes as well and has been designed carefully to avoid overhead for the regular fastpath. This includes the core changes and the x86 support code. - Simplification of the context tracking entry/exit handling for the users of the generic entry code which guarantee the proper ordering and protection. - Preparatory changes to make the generic entry code accomodate S390 specific requirements which are mostly related to their syscall restart mechanism" * tag 'core-entry-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits) entry: Add syscall_exit_to_user_mode_work() entry: Add exit_to_user_mode() wrapper entry_Add_enter_from_user_mode_wrapper entry: Rename exit_to_user_mode() entry: Rename enter_from_user_mode() docs: Document Syscall User Dispatch selftests: Add benchmark for syscall user dispatch selftests: Add kselftest for syscall user dispatch entry: Support Syscall User Dispatch on common syscall entry kernel: Implement selective syscall userspace redirection signal: Expose SYS_USER_DISPATCH si_code type x86: vdso: Expose sigreturn address on vdso to the kernel MAINTAINERS: Add entry for common entry code entry: Fix boot for !CONFIG_GENERIC_ENTRY x86: Support HAVE_CONTEXT_TRACKING_OFFSTACK context_tracking: Only define schedule_user() on !HAVE_CONTEXT_TRACKING_OFFSTACK archs sched: Detect call to schedule from critical entry code context_tracking: Don't implement exception_enter/exit() on CONFIG_HAVE_CONTEXT_TRACKING_OFFSTACK context_tracking: Introduce HAVE_CONTEXT_TRACKING_OFFSTACK x86: Reclaim unused x86 TI flags ...
2020-12-14Merge tag 'x86_cpu_for_v5.11' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cpuid updates from Borislav Petkov: "Only AMD-specific changes this time: - Save the AMD physical die ID into cpuinfo_x86.cpu_die_id and convert all code to use it (Yazen Ghannam) - Remove a dead and unused TSEG region remapping workaround on AMD (Arvind Sankar)" * tag 'x86_cpu_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/cpu/amd: Remove dead code for TSEG region remapping x86/topology: Set cpu_die_id only if DIE_TYPE found EDAC/mce_amd: Use struct cpuinfo_x86.cpu_die_id for AMD NodeId x86/CPU/AMD: Remove amd_get_nb_id() x86/CPU/AMD: Save AMD NodeId as cpu_die_id
2020-12-01x86/mce: Rename kill_it to kill_current_taskGabriele Paoloni
Currently, if an MCE happens in user-mode or while the kernel is copying data from user space, 'kill_it' is used to check if execution of the interrupted task can be recovered or not; the flag name however is not very meaningful, hence rename it to match its goal. [ bp: Massage commit message, rename the queue_task_work() arg too. ] Signed-off-by: Gabriele Paoloni <gabriele.paoloni@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20201127161819.3106432-6-gabriele.paoloni@intel.com
2020-12-01x86/mce: Remove redundant call to irq_work_queue()Gabriele Paoloni
Currently, __mc_scan_banks() in do_machine_check() does the following callchain: __mc_scan_banks()->mce_log()->irq_work_queue(&mce_irq_work). Hence, the call to irq_work_queue() below after __mc_scan_banks() seems redundant. Just remove it. Signed-off-by: Gabriele Paoloni <gabriele.paoloni@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://lkml.kernel.org/r/20201127161819.3106432-5-gabriele.paoloni@intel.com
2020-12-01x86/mce: Panic for LMCE only if mca_cfg.tolerant < 3Gabriele Paoloni
Right now for LMCE, if no_way_out is set, mce_panic() is called regardless of mca_cfg.tolerant. This is not correct as, if mca_cfg.tolerant = 3, the code should never panic. Add that check. [ bp: use local ptr 'cfg'. ] Signed-off-by: Gabriele Paoloni <gabriele.paoloni@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://lkml.kernel.org/r/20201127161819.3106432-4-gabriele.paoloni@intel.com
2020-12-01x86/mce: Move the mce_panic() call and 'kill_it' assignments to the right placesGabriele Paoloni
Right now, for local MCEs the machine calls panic(), if needed, right after lmce is set. For MCE broadcasting, mce_reign() takes care of calling mce_panic(). Hence: - improve readability by moving the conditional evaluation of tolerant up to when kill_it is set first; - move the mce_panic() call up into the statement where mce_end() fails. [ bp: Massage, remove comment in the mce_end() failure case because it is superfluous; use local ptr 'cfg' in both tests. ] Signed-off-by: Gabriele Paoloni <gabriele.paoloni@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://lkml.kernel.org/r/20201127161819.3106432-3-gabriele.paoloni@intel.com
2020-12-01Merge tag 'v5.10-rc6' into ras/coreBorislav Petkov
Merge the -rc6 tag to pick up dependent changes. Signed-off-by: Borislav Petkov <bp@suse.de>
2020-11-27x86/mce: Do not overwrite no_way_out if mce_end() failsGabriele Paoloni
Currently, if mce_end() fails, no_way_out - the variable denoting whether the machine can recover from this MCE - is determined by whether the worst severity that was found across the MCA banks associated with the current CPU, is of panic severity. However, at this point no_way_out could have been already set by mca_start() after looking at all severities of all CPUs that entered the MCE handler. If mce_end() fails, check first if no_way_out is already set and, if so, stick to it, otherwise use the local worst value. [ bp: Massage. ] Signed-off-by: Gabriele Paoloni <gabriele.paoloni@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20201127161819.3106432-2-gabriele.paoloni@intel.com
2020-11-21x86/mce, cper: Pass x86 CPER through the MCA handling chainSmita Koralahalli
The kernel uses ACPI Boot Error Record Table (BERT) to report fatal errors that occurred in a previous boot. The MCA errors in the BERT are reported using the x86 Processor Error Common Platform Error Record (CPER) format. Currently, the record prints out the raw MSR values and AMD relies on the raw record to provide MCA information. Extract the raw MSR values of MCA registers from the BERT and feed them into mce_log() to decode them properly. The implementation is SMCA-specific as the raw MCA register values are given in the register offset order of the SMCA address space. [ bp: Massage. ] [ Fix a build breakage in patch v1. ] Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Punit Agrawal <punit1.agrawal@toshiba.co.jp> Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lkml.kernel.org/r/20201119182938.151155-1-Smita.KoralahalliChannabasappa@amd.com
2020-11-19x86/CPU/AMD: Remove amd_get_nb_id()Yazen Ghannam
The Last Level Cache ID is returned by amd_get_nb_id(). In practice, this value is the same as the AMD NodeId for callers of this function. The NodeId is saved in struct cpuinfo_x86.cpu_die_id. Replace calls to amd_get_nb_id() with the logical CPU's cpu_die_id and remove the function. Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20201109210659.754018-3-Yazen.Ghannam@amd.com
2020-11-16x86/mce: Use "safe" MSR functions when enabling additional error loggingTony Luck
Booting as a guest under KVM results in error messages about unchecked MSR access: unchecked MSR access error: RDMSR from 0x17f at rIP: 0xffffffff84483f16 (mce_intel_feature_init+0x156/0x270) because KVM doesn't provide emulation for random model specific registers. Switch to using rdmsrl_safe()/wrmsrl_safe() to avoid the message. Fixes: 68299a42f842 ("x86/mce: Enable additional error logging on certain Intel CPUs") Reported-by: Qian Cai <cai@redhat.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20201111003954.GA11878@agluck-desk2.amr.corp.intel.com
2020-11-06x86/mce: Correct the detection of invalid notifier prioritiesZhen Lei
Commit c9c6d216ed28 ("x86/mce: Rename "first" function as "early"") changed the enumeration of MCE notifier priorities. Correct the check for notifier priorities to cover the new range. [ bp: Rewrite commit message, remove superfluous brackets in conditional. ] Fixes: c9c6d216ed28 ("x86/mce: Rename "first" function as "early"") Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20201106141216.2062-2-thunder.leizhen@huawei.com
2020-11-06x86/mce: Assign boolean values to a bool variableKaixu Xia
Fix the following coccinelle warnings: ./arch/x86/kernel/cpu/mce/core.c:1765:3-20: WARNING: Assignment of 0/1 to bool variable ./arch/x86/kernel/cpu/mce/core.c:1584:2-9: WARNING: Assignment of 0/1 to bool variable [ bp: Massage commit message. ] Reported-by: Tosk Robot <tencent_os_robot@tencent.com> Signed-off-by: Kaixu Xia <kaixuxia@tencent.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/1604654363-1463-1-git-send-email-kaixuxia@tencent.com
2020-11-04x86/entry: Move nmi entry/exit into common codeThomas Gleixner
Lockdep state handling on NMI enter and exit is nothing specific to X86. It's not any different on other architectures. Also the extra state type is not necessary, irqentry_state_t can carry the necessary information as well. Move it to common code and extend irqentry_state_t to carry lockdep state. [ Ira: Make exit_rcu and lockdep a union as they are mutually exclusive between the IRQ and NMI exceptions, and add kernel documentation for struct irqentry_state_t ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201102205320.1458656-7-ira.weiny@intel.com
2020-11-02x86/mce: Enable additional error logging on certain Intel CPUsTony Luck
The Xeon versions of Sandy Bridge, Ivy Bridge and Haswell support an optional additional error logging mode which is enabled by an MSR. Previously, this mode was enabled from the mcelog(8) tool via /dev/cpu, but userspace should not be poking at MSRs. So move the enabling into the kernel. [ bp: Correct the explanation why this is done. ] Suggested-by: Boris Petkov <bp@alien8.de> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20201030190807.GA13884@agluck-desk2.amr.corp.intel.com
2020-10-26x86/mce: Remove unneeded breakTom Rix
A break is not needed if it is preceded by a return. Signed-off-by: Tom Rix <trix@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20201019200803.17619-1-trix@redhat.com
2020-10-17task_work: cleanup notification modesJens Axboe
A previous commit changed the notification mode from true/false to an int, allowing notify-no, notify-yes, or signal-notify. This was backwards compatible in the sense that any existing true/false user would translate to either 0 (on notification sent) or 1, the latter which mapped to TWA_RESUME. TWA_SIGNAL was assigned a value of 2. Clean this up properly, and define a proper enum for the notification mode. Now we have: - TWA_NONE. This is 0, same as before the original change, meaning no notification requested. - TWA_RESUME. This is 1, same as before the original change, meaning that we use TIF_NOTIFY_RESUME. - TWA_SIGNAL. This uses TIF_SIGPENDING/JOBCTL_TASK_WORK for the notification. Clean up all the callers, switching their 0/1/false/true to using the appropriate TWA_* mode for notifications. Fixes: e91b48162332 ("task_work: teach task_work_add() to do signal_wake_up()") Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-12Merge tag 'ras_updates_for_v5.10' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RAS updates from Borislav Petkov: - Extend the recovery from MCE in kernel space also to processes which encounter an MCE in kernel space but while copying from user memory by sending them a SIGBUS on return to user space and umapping the faulty memory, by Tony Luck and Youquan Song. - memcpy_mcsafe() rework by splitting the functionality into copy_mc_to_user() and copy_mc_to_kernel(). This, as a result, enables support for new hardware which can recover from a machine check encountered during a fast string copy and makes that the default and lets the older hardware which does not support that advance recovery, opt in to use the old, fragile, slow variant, by Dan Williams. - New AMD hw enablement, by Yazen Ghannam and Akshay Gupta. - Do not use MSR-tracing accessors in #MC context and flag any fault while accessing MCA architectural MSRs as an architectural violation with the hope that such hw/fw misdesigns are caught early during the hw eval phase and they don't make it into production. - Misc fixes, improvements and cleanups, as always. * tag 'ras_updates_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mce: Allow for copy_mc_fragile symbol checksum to be generated x86/mce: Decode a kernel instruction to determine if it is copying from user x86/mce: Recover from poison found while copying from user space x86/mce: Avoid tail copy when machine check terminated a copy from user x86/mce: Add _ASM_EXTABLE_CPY for copy user access x86/mce: Provide method to find out the type of an exception handler x86/mce: Pass pointer to saved pt_regs to severity calculation routines x86/copy_mc: Introduce copy_mc_enhanced_fast_string() x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}() x86/mce: Drop AMD-specific "DEFERRED" case from Intel severity rule list x86/mce: Add Skylake quirk for patrol scrub reported errors RAS/CEC: Convert to DEFINE_SHOW_ATTRIBUTE() x86/mce: Annotate mce_rd/wrmsrl() with noinstr x86/mce/dev-mcelog: Do not update kflags on AMD systems x86/mce: Stop mce_reign() from re-computing severity for every CPU x86/mce: Make mce_rdmsrl() panic on an inaccessible MSR x86/mce: Increase maximum number of banks to 64 x86/mce: Delay clearing IA32_MCG_STATUS to the end of do_machine_check() x86/MCE/AMD, EDAC/mce_amd: Remove struct smca_hwid.xec_bitmap RAS/CEC: Fix cec_init() prototype
2020-10-07x86/mce: Decode a kernel instruction to determine if it is copying from userTony Luck
All instructions copying data between kernel and user memory are tagged with either _ASM_EXTABLE_UA or _ASM_EXTABLE_CPY entries in the exception table. ex_fault_handler_type() returns EX_HANDLER_UACCESS for both of these. Recovery is only possible when the machine check was triggered on a read from user memory. In this case the same strategy for recovery applies as if the user had made the access in ring3. If the fault was in kernel memory while copying to user there is no current recovery plan. For MOV and MOVZ instructions a full decode of the instruction is done to find the source address. For MOVS instructions the source address is in the %rsi register. The function fault_in_kernel_space() determines whether the source address is kernel or user, upgrade it from "static" so it can be used here. Co-developed-by: Youquan Song <youquan.song@intel.com> Signed-off-by: Youquan Song <youquan.song@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20201006210910.21062-7-tony.luck@intel.com
2020-10-07x86/mce: Recover from poison found while copying from user spaceTony Luck
Existing kernel code can only recover from a machine check on code that is tagged in the exception table with a fault handling recovery path. Add two new fields in the task structure to pass information from machine check handler to the "task_work" that is queued to run before the task returns to user mode: + mce_vaddr: will be initialized to the user virtual address of the fault in the case where the fault occurred in the kernel copying data from a user address. This is so that kill_me_maybe() can provide that information to the user SIGBUS handler. + mce_kflags: copy of the struct mce.kflags needed by kill_me_maybe() to determine if mce_vaddr is applicable to this error. Add code to recover from a machine check while copying data from user space to the kernel. Action for this case is the same as if the user touched the poison directly; unmap the page and send a SIGBUS to the task. Use a new helper function to share common code between the "fault in user mode" case and the "fault while copying from user" case. New code paths will be activated by the next patch which sets MCE_IN_KERNEL_COPYIN. Suggested-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20201006210910.21062-6-tony.luck@intel.com
2020-10-07x86/mce: Provide method to find out the type of an exception handlerTony Luck
Avoid a proliferation of ex_has_*_handler() functions by having just one function that returns the type of the handler (if any). Drop the __visible attribute for this function. It is not called from assembler so the attribute is not necessary. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20201006210910.21062-3-tony.luck@intel.com
2020-10-07x86/mce: Pass pointer to saved pt_regs to severity calculation routinesYouquan Song
New recovery features require additional information about processor state when a machine check occurred. Pass pt_regs down to the routines that need it. No functional change. Signed-off-by: Youquan Song <youquan.song@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20201006210910.21062-2-tony.luck@intel.com
2020-10-06x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()Dan Williams
In reaction to a proposal to introduce a memcpy_mcsafe_fast() implementation Linus points out that memcpy_mcsafe() is poorly named relative to communicating the scope of the interface. Specifically what addresses are valid to pass as source, destination, and what faults / exceptions are handled. Of particular concern is that even though x86 might be able to handle the semantics of copy_mc_to_user() with its common copy_user_generic() implementation other archs likely need / want an explicit path for this case: On Fri, May 1, 2020 at 11:28 AM Linus Torvalds <torvalds@linux-foundation.org> wrote: > > On Thu, Apr 30, 2020 at 6:21 PM Dan Williams <dan.j.williams@intel.com> wrote: > > > > However now I see that copy_user_generic() works for the wrong reason. > > It works because the exception on the source address due to poison > > looks no different than a write fault on the user address to the > > caller, it's still just a short copy. So it makes copy_to_user() work > > for the wrong reason relative to the name. > > Right. > > And it won't work that way on other architectures. On x86, we have a > generic function that can take faults on either side, and we use it > for both cases (and for the "in_user" case too), but that's an > artifact of the architecture oddity. > > In fact, it's probably wrong even on x86 - because it can hide bugs - > but writing those things is painful enough that everybody prefers > having just one function. Replace a single top-level memcpy_mcsafe() with either copy_mc_to_user(), or copy_mc_to_kernel(). Introduce an x86 copy_mc_fragile() name as the rename for the low-level x86 implementation formerly named memcpy_mcsafe(). It is used as the slow / careful backend that is supplanted by a fast copy_mc_generic() in a follow-on patch. One side-effect of this reorganization is that separating copy_mc_64.S to its own file means that perf no longer needs to track dependencies for its memcpy_64.S benchmarks. [ bp: Massage a bit. ] Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: <stable@vger.kernel.org> Link: http://lore.kernel.org/r/CAHk-=wjSqtXAqfUJxFtWNwmguFASTgB0dz1dT3V-78Quiezqbg@mail.gmail.com Link: https://lkml.kernel.org/r/160195561680.2163339.11574962055305783722.stgit@dwillia2-desk3.amr.corp.intel.com
2020-09-30x86/mce: Use idtentry_nmi_enter/exit()Thomas Gleixner
The recent fix for NMI vs. IRQ state tracking missed to apply the cure to the MCE handler. Fixes: ba1f2b2eaa2a ("x86/entry: Fix NMI vs IRQ state tracking") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/87mu17ism2.fsf@nanos.tec.linutronix.de
2020-09-30x86/mce: Drop AMD-specific "DEFERRED" case from Intel severity rule listTony Luck
Way back in v3.19 Intel and AMD shared the same machine check severity grading code. So it made sense to add a case for AMD DEFERRED errors in commit e3480271f592 ("x86, mce, severity: Extend the the mce_severity mechanism to handle UCNA/DEFERRED error") But later in v4.2 AMD switched to a separate grading function in commit bf80bbd7dcf5 ("x86/mce: Add an AMD severities-grading function") Belatedly drop the DEFERRED case from the Intel rule list. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200930021313.31810-3-tony.luck@intel.com
2020-09-30x86/mce: Add Skylake quirk for patrol scrub reported errorsBorislav Petkov
The patrol scrubber in Skylake and Cascade Lake systems can be configured to report uncorrected errors using a special signature in the machine check bank and to signal using CMCI instead of machine check. Update the severity calculation mechanism to allow specifying the model, minimum stepping and range of machine check bank numbers. Add a new rule to detect the special signature (on model 0x55, stepping >=4 in any of the memory controller banks). [ bp: Rewrite it. aegl: Productize it. ] Suggested-by: Youquan Song <youquan.song@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Co-developed-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200930021313.31810-2-tony.luck@intel.com
2020-09-18x86/mce: Annotate mce_rd/wrmsrl() with noinstrBorislav Petkov
They do get called from the #MC handler which is already marked "noinstr". Commit e2def7d49d08 ("x86/mce: Make mce_rdmsrl() panic on an inaccessible MSR") already got rid of the instrumentation in the MSR accessors, fix the annotation now too, in order to get rid of: vmlinux.o: warning: objtool: do_machine_check()+0x4a: call to mce_rdmsrl() leaves .noinstr.text section Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200915194020.28807-1-bp@alien8.de
2020-09-15x86/mce/dev-mcelog: Do not update kflags on AMD systemsSmita Koralahalli
The mcelog utility is not commonly used on AMD systems. Therefore, errors logged only by the dev_mce_log() notifier will be missed. This may occur if the EDAC modules are not loaded, in which case it's preferable to print the error record by the default notifier. However, the mce->kflags set by dev_mce_log() notifier makes the default notifier skip over the errors assuming they are processed by dev_mce_log(). Do not update kflags in the dev_mce_log() notifier on AMD systems. Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200903234531.162484-3-Smita.KoralahalliChannabasappa@amd.com
2020-09-14x86/mce: Stop mce_reign() from re-computing severity for every CPUTony Luck
Back in commit: 20d51a426fe9 ("x86/mce: Reuse one of the u16 padding fields in 'struct mce'") a field was added to "struct mce" to save the computed error severity. Make use of this in mce_reign() to avoid re-computing the severity for every CPU. In the case where the machine panics, one call to mce_severity() is still needed in order to provide the correct message giving the reason for the panic. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200908175519.14223-2-tony.luck@intel.com
2020-09-11x86/mce: Make mce_rdmsrl() panic on an inaccessible MSRBorislav Petkov
If an exception needs to be handled while reading an MSR - which is in most of the cases caused by a #GP on a non-existent MSR - then this is most likely the incarnation of a BIOS or a hardware bug. Such bug violates the architectural guarantee that MCA banks are present with all MSRs belonging to them. The proper fix belongs in the hardware/firmware - not in the kernel. Handling an #MC exception which is raised while an NMI is being handled would cause the nasty NMI nesting issue because of the shortcoming of IRET of reenabling NMIs when executed. And the machine is in an #MC context already so <Deity> be at its side. Tracing MSR accesses while in #MC is another no-no due to tracing being inherently a bad idea in atomic context: vmlinux.o: warning: objtool: do_machine_check()+0x4a: call to mce_rdmsrl() leaves .noinstr.text section so remove all that "additional" functionality from mce_rdmsrl() and provide it with a special exception handler which panics the machine when that MSR is not accessible. The exception handler prints a human-readable message explaining what the panic reason is but, what is more, it panics while in the #GP handler and latter won't have executed an IRET, thus opening the NMI nesting issue in the case when the #MC has happened while handling an NMI. (#MC itself won't be reenabled until MCG_STATUS hasn't been cleared). Suggested-by: Andy Lutomirski <luto@kernel.org> Suggested-by: Peter Zijlstra <peterz@infradead.org> [ Add missing prototypes for ex_handler_* ] Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://lkml.kernel.org/r/20200906212130.GA28456@zn.tnic
2020-08-26x86/mce: Delay clearing IA32_MCG_STATUS to the end of do_machine_check()Tony Luck
A long time ago, Linux cleared IA32_MCG_STATUS at the very end of machine check processing. Then, some fancy recovery and IST manipulation was added in: d4812e169de4 ("x86, mce: Get rid of TIF_MCE_NOTIFY and associated mce tricks") and clearing IA32_MCG_STATUS was pulled earlier in the function. Next change moved the actual recovery out of do_machine_check() and just used task_work_add() to schedule it later (before returning to the user): 5567d11c21a1 ("x86/mce: Send #MC singal from task work") Most recently the fancy IST footwork was removed as no longer needed: b052df3da821 ("x86/entry: Get rid of ist_begin/end_non_atomic()") At this point there is no reason remaining to clear IA32_MCG_STATUS early. It can move back to the very end of the function. Also move sync_core(). The comments for this function say that it should only be called when instructions have been changed/re-mapped. Recovery for an instruction fetch may change the physical address. But that doesn't happen until the scheduled work runs (which could be on another CPU). [ bp: Massage commit message. ] Reported-by: Gabriele Paoloni <gabriele.paoloni@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200824221237.5397-1-tony.luck@intel.com
2020-08-23treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-20x86/MCE/AMD, EDAC/mce_amd: Remove struct smca_hwid.xec_bitmapYazen Ghannam
The Extended Error Code Bitmap (xec_bitmap) for a Scalable MCA bank type was intended to be used by the kernel to filter out invalid error codes on a system. However, this is unnecessary after a few product releases because the hardware will only report valid error codes. Thus, there's no need for it with future systems. Remove the xec_bitmap field and all references to it. Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200720145353.43924-1-Yazen.Ghannam@amd.com
2020-08-04Merge tag 'x86-entry-2020-08-04' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 conversion to generic entry code from Thomas Gleixner: "The conversion of X86 syscall, interrupt and exception entry/exit handling to the generic code. Pretty much a straight-forward 1:1 conversion plus the consolidation of the KVM handling of pending work before entering guest mode" * tag 'x86-entry-2020-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/kvm: Use __xfer_to_guest_mode_work_pending() in kvm_run_vcpu() x86/kvm: Use generic xfer to guest work function x86/entry: Cleanup idtentry_enter/exit x86/entry: Use generic interrupt entry/exit code x86/entry: Cleanup idtentry_entry/exit_user x86/entry: Use generic syscall exit functionality x86/entry: Use generic syscall entry function x86/ptrace: Provide pt_regs helper for entry/exit x86/entry: Move user return notifier out of loop x86/entry: Consolidate 32/64 bit syscall entry x86/entry: Consolidate check_user_regs() x86: Correct noinstr qualifiers x86/idtentry: Remove stale comment
2020-08-03Merge tag 'ras-core-2020-08-03' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 RAS updates from Ingo Molnar: "Boris is on vacation and he asked us to send you the pending RAS bits: - Print the PPIN field on CPUs that fill them out - Fix an MCE injection bug - Simplify a kzalloc in dev_mcelog_init_device()" * tag 'ras-core-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mce, EDAC/mce_amd: Print PPIN in machine check records x86/mce/dev-mcelog: Use struct_size() helper in kzalloc() x86/mce/inject: Fix a wrong assignment of i_mce.status
2020-07-27x86/cpu: Relocate sync_core() to sync_core.hRicardo Neri
Having sync_core() in processor.h is problematic since it is not possible to check for hardware capabilities via the *cpu_has() family of macros. The latter needs the definitions in processor.h. It also looks more intuitive to relocate the function to sync_core.h. This changeset does not make changes in functionality. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/r/20200727043132.15082-3-ricardo.neri-calderon@linux.intel.com
2020-07-24x86/entry: Cleanup idtentry_entry/exit_userThomas Gleixner
Cleanup the temporary defines and use irqentry_ instead of idtentry_. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200722220520.602603691@linutronix.de
2020-07-24x86: Correct noinstr qualifiersIra Weiny
The noinstr qualifier is to be specified before the return type in the same way inline is used. These 2 cases were missed by previous patches. Signed-off-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://lkml.kernel.org/r/20200723161405.852613-1-ira.weiny@intel.com
2020-07-05Merge tag 'x86-urgent-2020-07-05' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Thomas Gleixner: "A series of fixes for x86: - Reset MXCSR in kernel_fpu_begin() to prevent using a stale user space value. - Prevent writing MSR_TEST_CTRL on CPUs which are not explicitly whitelisted for split lock detection. Some CPUs which do not support it crash even when the MSR is written to 0 which is the default value. - Fix the XEN PV fallout of the entry code rework - Fix the 32bit fallout of the entry code rework - Add more selftests to ensure that these entry problems don't come back. - Disable 16 bit segments on XEN PV. It's not supported because XEN PV does not implement ESPFIX64" * tag 'x86-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/ldt: Disable 16-bit segments on Xen PV x86/entry/32: Fix #MC and #DB wiring on x86_32 x86/entry/xen: Route #DB correctly on Xen PV x86/entry, selftests: Further improve user entry sanity checks x86/entry/compat: Clear RAX high bits on Xen PV SYSENTER selftests/x86: Consolidate and fix get/set_eflags() helpers selftests/x86/syscall_nt: Clear weird flags after each test selftests/x86/syscall_nt: Add more flag combinations x86/entry/64/compat: Fix Xen PV SYSENTER frame setup x86/entry: Move SYSENTER's regs->sp and regs->flags fixups into C x86/entry: Assert that syscalls are on the right stack x86/split_lock: Don't write MSR_TEST_CTRL on CPUs that aren't whitelisted x86/fpu: Reset MXCSR to default in kernel_fpu_begin()
2020-07-04x86/entry/32: Fix #MC and #DB wiring on x86_32Andy Lutomirski
DEFINE_IDTENTRY_MCE and DEFINE_IDTENTRY_DEBUG were wired up as non-RAW on x86_32, but the code expected them to be RAW. Get rid of all the macro indirection for them on 32-bit and just use DECLARE_IDTENTRY_RAW and DEFINE_IDTENTRY_RAW directly. Also add a warning to make sure that we only hit the _kernel paths in kernel mode. Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/9e90a7ee8e72fd757db6d92e1e5ff16339c1ecf9.1593795633.git.luto@kernel.org