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2019-09-01Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds7-39/+43
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Thomas Gleixner: "A set of fixes for x86: - Fix the bogus detection of 32bit user mode for uretprobes which caused corruption of the user return address resulting in application crashes. In the uprobes handler in_ia32_syscall() is obviously always returning false on a 64bit kernel. Use user_64bit_mode() instead which works correctly. - Prevent large page splitting when ftrace flips RW/RO on the kernel text which caused iTLB performance issues. Ftrace wants to be converted to text_poke() which avoids the problem, but for now allow large page preservation in the static protections check when the change request spawns a full large page. - Prevent arch_dynirq_lower_bound() from returning 0 when the IOAPIC is configured via device tree. In the device tree case the GSI 1:1 mapping is meaningless therefore the lower bound which protects the GSI range on ACPI machines is irrelevant. Return the lower bound which the core hands to the function instead of blindly returning 0 which causes the core to allocate the invalid virtual interupt number 0 which in turn prevents all drivers from allocating and requesting an interrupt. - Remove the bogus initialization of LDR and DFR in the 32bit bigsmp APIC driver. That uses physical destination mode where LDR/DFR are ignored, but the initialization and the missing clear of LDR caused the APIC to be left in a inconsistent state on kexec/reboot. - Clear LDR when clearing the APIC registers so the APIC is in a well defined state. - Initialize variables proper in the find_trampoline_placement() code. - Silence GCC( build warning for the real mode part of the build" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm/cpa: Prevent large page split when ftrace flips RW on kernel text x86/build: Add -Wnoaddress-of-packed-member to REALMODE_CFLAGS, to silence GCC9 build warning x86/boot/compressed/64: Fix missing initialization in find_trampoline_placement() x86/apic: Include the LDR when clearing out APIC registers x86/apic: Do not initialize LDR and DFR for bigsmp uprobes/x86: Fix detection of 32-bit user mode x86/apic: Fix arch_dynirq_lower_bound() bug for DT enabled machines
2019-09-01Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds3-7/+24
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Thomas Gleixner: "Two fixes for perf x86 hardware implementations: - Restrict the period on Nehalem machines to prevent perf from hogging the CPU - Prevent the AMD IBS driver from overwriting the hardwre controlled and pre-seeded reserved bits (0-6) in the count register which caused a sample bias for dispatched micro-ops" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/amd/ibs: Fix sample bias for dispatched micro-ops perf/x86/intel: Restrict period on Nehalem
2019-08-31Merge tag 'trace-v5.3-rc6' of ↵Linus Torvalds1-1/+0
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fixes from Steven Rostedt: "Small fixes and minor cleanups for tracing: - Make exported ftrace function not static - Fix NULL pointer dereference in reading probes as they are created - Fix NULL pointer dereference in k/uprobe clean up path - Various documentation fixes" * tag 'trace-v5.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Correct kdoc formats ftrace/x86: Remove mcount() declaration tracing/probe: Fix null pointer dereference tracing: Make exported ftrace_set_clr_event non-static ftrace: Check for successful allocation of hash ftrace: Check for empty hash and comment the race with registering probes ftrace: Fix NULL pointer dereference in t_probe_next()
2019-08-31ftrace/x86: Remove mcount() declarationJisheng Zhang1-1/+0
Commit 562e14f72292 ("ftrace/x86: Remove mcount support") removed the support for using mcount, so we could remove the mcount() declaration to clean up. Link: http://lkml.kernel.org/r/20190826170150.10f101ba@xhacker.debian Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-08-30perf/x86/amd/ibs: Fix sample bias for dispatched micro-opsKim Phillips2-7/+18
When counting dispatched micro-ops with cnt_ctl=1, in order to prevent sample bias, IBS hardware preloads the least significant 7 bits of current count (IbsOpCurCnt) with random values, such that, after the interrupt is handled and counting resumes, the next sample taken will be slightly perturbed. The current count bitfield is in the IBS execution control h/w register, alongside the maximum count field. Currently, the IBS driver writes that register with the maximum count, leaving zeroes to fill the current count field, thereby overwriting the random bits the hardware preloaded for itself. Fix the driver to actually retain and carry those random bits from the read of the IBS control register, through to its write, instead of overwriting the lower current count bits with zeroes. Tested with: perf record -c 100001 -e ibs_op/cnt_ctl=1/pp -a -C 0 taskset -c 0 <workload> 'perf annotate' output before: 15.70 65: addsd %xmm0,%xmm1 17.30 add $0x1,%rax 15.88 cmp %rdx,%rax je 82 17.32 72: test $0x1,%al jne 7c 7.52 movapd %xmm1,%xmm0 5.90 jmp 65 8.23 7c: sqrtsd %xmm1,%xmm0 12.15 jmp 65 'perf annotate' output after: 16.63 65: addsd %xmm0,%xmm1 16.82 add $0x1,%rax 16.81 cmp %rdx,%rax je 82 16.69 72: test $0x1,%al jne 7c 8.30 movapd %xmm1,%xmm0 8.13 jmp 65 8.24 7c: sqrtsd %xmm1,%xmm0 8.39 jmp 65 Tested on Family 15h and 17h machines. Machines prior to family 10h Rev. C don't have the RDWROPCNT capability, and have the IbsOpCurCnt bitfield reserved, so this patch shouldn't affect their operation. It is unknown why commit db98c5faf8cb ("perf/x86: Implement 64-bit counter support for IBS") ignored the lower 4 bits of the IbsOpCurCnt field; the number of preloaded random bits has always been 7, AFAICT. Signed-off-by: Kim Phillips <kim.phillips@amd.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: "Arnaldo Carvalho de Melo" <acme@kernel.org> Cc: <x86@kernel.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "Borislav Petkov" <bp@alien8.de> Cc: Stephane Eranian <eranian@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: "Namhyung Kim" <namhyung@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Link: https://lkml.kernel.org/r/20190826195730.30614-1-kim.phillips@amd.com
2019-08-30perf/x86/intel: Restrict period on NehalemJosh Hunt1-0/+6
We see our Nehalem machines reporting 'perfevents: irq loop stuck!' in some cases when using perf: perfevents: irq loop stuck! WARNING: CPU: 0 PID: 3485 at arch/x86/events/intel/core.c:2282 intel_pmu_handle_irq+0x37b/0x530 ... RIP: 0010:intel_pmu_handle_irq+0x37b/0x530 ... Call Trace: <NMI> ? perf_event_nmi_handler+0x2e/0x50 ? intel_pmu_save_and_restart+0x50/0x50 perf_event_nmi_handler+0x2e/0x50 nmi_handle+0x6e/0x120 default_do_nmi+0x3e/0x100 do_nmi+0x102/0x160 end_repeat_nmi+0x16/0x50 ... ? native_write_msr+0x6/0x20 ? native_write_msr+0x6/0x20 </NMI> intel_pmu_enable_event+0x1ce/0x1f0 x86_pmu_start+0x78/0xa0 x86_pmu_enable+0x252/0x310 __perf_event_task_sched_in+0x181/0x190 ? __switch_to_asm+0x41/0x70 ? __switch_to_asm+0x35/0x70 ? __switch_to_asm+0x41/0x70 ? __switch_to_asm+0x35/0x70 finish_task_switch+0x158/0x260 __schedule+0x2f6/0x840 ? hrtimer_start_range_ns+0x153/0x210 schedule+0x32/0x80 schedule_hrtimeout_range_clock+0x8a/0x100 ? hrtimer_init+0x120/0x120 ep_poll+0x2f7/0x3a0 ? wake_up_q+0x60/0x60 do_epoll_wait+0xa9/0xc0 __x64_sys_epoll_wait+0x1a/0x20 do_syscall_64+0x4e/0x110 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fdeb1e96c03 ... Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: acme@kernel.org Cc: Josh Hunt <johunt@akamai.com> Cc: bpuranda@akamai.com Cc: mingo@redhat.com Cc: jolsa@redhat.com Cc: tglx@linutronix.de Cc: namhyung@kernel.org Cc: alexander.shishkin@linux.intel.com Link: https://lkml.kernel.org/r/1566256411-18820-1-git-send-email-johunt@akamai.com
2019-08-29x86/mm/cpa: Prevent large page split when ftrace flips RW on kernel textThomas Gleixner1-8/+18
ftrace does not use text_poke() for enabling trace functionality. It uses its own mechanism and flips the whole kernel text to RW and back to RO. The CPA rework removed a loop based check of 4k pages which tried to preserve a large page by checking each 4k page whether the change would actually cover all pages in the large page. This resulted in endless loops for nothing as in testing it turned out that it actually never preserved anything. Of course testing missed to include ftrace, which is the one and only case which benefitted from the 4k loop. As a consequence enabling function tracing or ftrace based kprobes results in a full 4k split of the kernel text, which affects iTLB performance. The kernel RO protection is the only valid case where this can actually preserve large pages. All other static protections (RO data, data NX, PCI, BIOS) are truly static. So a conflict with those protections which results in a split should only ever happen when a change of memory next to a protected region is attempted. But these conflicts are rightfully splitting the large page to preserve the protected regions. In fact a change to the protected regions itself is a bug and is warned about. Add an exception for the static protection check for kernel text RO when the to be changed region spawns a full large page which allows to preserve the large mappings. This also prevents the syslog to be spammed about CPA violations when ftrace is used. The exception needs to be removed once ftrace switched over to text_poke() which avoids the whole issue. Fixes: 585948f4f695 ("x86/mm/cpa: Avoid the 4k pages check completely") Reported-by: Song Liu <songliubraving@fb.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Song Liu <songliubraving@fb.com> Reviewed-by: Song Liu <songliubraving@fb.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1908282355340.1938@nanos.tec.linutronix.de
2019-08-28x86/build: Add -Wnoaddress-of-packed-member to REALMODE_CFLAGS, to silence ↵Linus Torvalds1-0/+1
GCC9 build warning One of the very few warnings I have in the current build comes from arch/x86/boot/edd.c, where I get the following with a gcc9 build: arch/x86/boot/edd.c: In function ‘query_edd’: arch/x86/boot/edd.c:148:11: warning: taking address of packed member of ‘struct boot_params’ may result in an unaligned pointer value [-Waddress-of-packed-member] 148 | mbrptr = boot_params.edd_mbr_sig_buffer; | ^~~~~~~~~~~ This warning triggers because we throw away all the CFLAGS and then make a new set for REALMODE_CFLAGS, so the -Wno-address-of-packed-member we added in the following commit is not present: 6f303d60534c ("gcc-9: silence 'address-of-packed-member' warning") The simplest solution for now is to adjust the warning for this version of CFLAGS as well, but it would definitely make sense to examine whether REALMODE_CFLAGS could be derived from CFLAGS, so that it picks up changes in the compiler flags environment automatically. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Borislav Petkov <bp@alien8.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-08-27KVM: x86: Don't update RIP or do single-step on faulting emulationSean Christopherson1-4/+5
Don't advance RIP or inject a single-step #DB if emulation signals a fault. This logic applies to all state updates that are conditional on clean retirement of the emulation instruction, e.g. updating RFLAGS was previously handled by commit 38827dbd3fb85 ("KVM: x86: Do not update EFLAGS on faulting emulation"). Not advancing RIP is likely a nop, i.e. ctxt->eip isn't updated with ctxt->_eip until emulation "retires" anyways. Skipping #DB injection fixes a bug reported by Andy Lutomirski where a #UD on SYSCALL due to invalid state with EFLAGS.TF=1 would loop indefinitely due to emulation overwriting the #UD with #DB and thus restarting the bad SYSCALL over and over. Cc: Nadav Amit <nadav.amit@gmail.com> Cc: stable@vger.kernel.org Reported-by: Andy Lutomirski <luto@kernel.org> Fixes: 663f4c61b803 ("KVM: x86: handle singlestep during emulation") Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2019-08-27KVM: x86: hyper-v: don't crash on KVM_GET_SUPPORTED_HV_CPUID when ↵Vitaly Kuznetsov3-8/+6
kvm_intel.nested is disabled If kvm_intel is loaded with nested=0 parameter an attempt to perform KVM_GET_SUPPORTED_HV_CPUID results in OOPS as nested_get_evmcs_version hook in kvm_x86_ops is NULL (we assign it in nested_vmx_hardware_setup() and this only happens in case nested is enabled). Check that kvm_x86_ops->nested_get_evmcs_version is not NULL before calling it. With this, we can remove the stub from svm as it is no longer needed. Cc: <stable@vger.kernel.org> Fixes: e2e871ab2f02 ("x86/kvm/hyper-v: Introduce nested_get_evmcs_version() helper") Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Jim Mattson <jmattson@google.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2019-08-27x86/boot/compressed/64: Fix missing initialization in ↵Kirill A. Shutemov1-1/+1
find_trampoline_placement() Gustavo noticed that 'new' can be left uninitialized if 'bios_start' happens to be less or equal to 'entry->addr + entry->size'. Initialize the variable at the begin of the iteration to the current value of 'bios_start'. Fixes: 0a46fff2f910 ("x86/boot/compressed/64: Fix boot on machines with broken E820 table") Reported-by: "Gustavo A. R. Silva" <gustavo@embeddedor.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190826133326.7cxb4vbmiawffv2r@box
2019-08-26x86/apic: Include the LDR when clearing out APIC registersBandan Das1-0/+4
Although APIC initialization will typically clear out the LDR before setting it, the APIC cleanup code should reset the LDR. This was discovered with a 32-bit KVM guest jumping into a kdump kernel. The stale bits in the LDR triggered a bug in the KVM APIC implementation which caused the destination mapping for VCPUs to be corrupted. Note that this isn't intended to paper over the KVM APIC bug. The kernel has to clear the LDR when resetting the APIC registers except when X2APIC is enabled. This lacks a Fixes tag because missing to clear LDR goes way back into pre git history. [ tglx: Made x2apic_enabled a function call as required ] Signed-off-by: Bandan Das <bsd@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190826101513.5080-3-bsd@redhat.com
2019-08-26x86/apic: Do not initialize LDR and DFR for bigsmpBandan Das1-22/+2
Legacy apic init uses bigsmp for smp systems with 8 and more CPUs. The bigsmp APIC implementation uses physical destination mode, but it nevertheless initializes LDR and DFR. The LDR even ends up incorrectly with multiple bit being set. This does not cause a functional problem because LDR and DFR are ignored when physical destination mode is active, but it triggered a problem on a 32-bit KVM guest which jumps into a kdump kernel. The multiple bits set unearthed a bug in the KVM APIC implementation. The code which creates the logical destination map for VCPUs ignores the disabled state of the APIC and ends up overwriting an existing valid entry and as a result, APIC calibration hangs in the guest during kdump initialization. Remove the bogus LDR/DFR initialization. This is not intended to work around the KVM APIC bug. The LDR/DFR ininitalization is wrong on its own. The issue goes back into the pre git history. The fixes tag is the commit in the bitkeeper import which introduced bigsmp support in 2003. git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git Fixes: db7b9e9f26b8 ("[PATCH] Clustered APIC setup for >8 CPU systems") Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Bandan Das <bsd@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190826101513.5080-2-bsd@redhat.com
2019-08-26uprobes/x86: Fix detection of 32-bit user modeSebastian Mayr1-7/+10
32-bit processes running on a 64-bit kernel are not always detected correctly, causing the process to crash when uretprobes are installed. The reason for the crash is that in_ia32_syscall() is used to determine the process's mode, which only works correctly when called from a syscall. In the case of uretprobes, however, the function is called from a exception and always returns 'false' on a 64-bit kernel. In consequence this leads to corruption of the process's return address. Fix this by using user_64bit_mode() instead of in_ia32_syscall(), which is correct in any situation. [ tglx: Add a comment and the following historical info ] This should have been detected by the rename which happened in commit abfb9498ee13 ("x86/entry: Rename is_{ia32,x32}_task() to in_{ia32,x32}_syscall()") which states in the changelog: The is_ia32_task()/is_x32_task() function names are a big misnomer: they suggests that the compat-ness of a system call is a task property, which is not true, the compatness of a system call purely depends on how it was invoked through the system call layer. ..... and then it went and blindly renamed every call site. Sadly enough this was already mentioned here: 8faaed1b9f50 ("uprobes/x86: Introduce sizeof_long(), cleanup adjust_ret_addr() and arch_uretprobe_hijack_return_addr()") where the changelog says: TODO: is_ia32_task() is not what we actually want, TS_COMPAT does not necessarily mean 32bit. Fortunately syscall-like insns can't be probed so it actually works, but it would be better to rename and use is_ia32_frame(). and goes all the way back to: 0326f5a94dde ("uprobes/core: Handle breakpoint and singlestep exceptions") Oh well. 7+ years until someone actually tried a uretprobe on a 32bit process on a 64bit kernel.... Fixes: 0326f5a94dde ("uprobes/core: Handle breakpoint and singlestep exceptions") Signed-off-by: Sebastian Mayr <me@sam.st> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190728152617.7308-1-me@sam.st
2019-08-26x86/apic: Fix arch_dynirq_lower_bound() bug for DT enabled machinesThomas Gleixner1-1/+7
Rahul Tanwar reported the following bug on DT systems: > 'ioapic_dynirq_base' contains the virtual IRQ base number. Presently, it is > updated to the end of hardware IRQ numbers but this is done only when IOAPIC > configuration type is IOAPIC_DOMAIN_LEGACY or IOAPIC_DOMAIN_STRICT. There is > a third type IOAPIC_DOMAIN_DYNAMIC which applies when IOAPIC configuration > comes from devicetree. > > See dtb_add_ioapic() in arch/x86/kernel/devicetree.c > > In case of IOAPIC_DOMAIN_DYNAMIC (DT/OF based system), 'ioapic_dynirq_base' > remains to zero initialized value. This means that for OF based systems, > virtual IRQ base will get set to zero. Such systems will very likely not even boot. For DT enabled machines ioapic_dynirq_base is irrelevant and not updated, so simply map the IRQ base 1:1 instead. Reported-by: Rahul Tanwar <rahul.tanwar@linux.intel.com> Tested-by: Rahul Tanwar <rahul.tanwar@linux.intel.com> Tested-by: Andy Shevchenko <andriy.shevchenko@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: alan@linux.intel.com Cc: bp@alien8.de Cc: cheol.yong.kim@intel.com Cc: qi-ming.wu@intel.com Cc: rahul.tanwar@intel.com Cc: rppt@linux.ibm.com Cc: tony.luck@intel.com Link: http://lkml.kernel.org/r/20190821081330.1187-1-rahul.tanwar@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-08-25Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds8-33/+220
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Thomas Gleixner: "A few fixes for x86: - Fix a boot regression caused by the recent bootparam sanitizing change, which escaped the attention of all people who reviewed that code. - Address a boot problem on machines with broken E820 tables caused by an underflow which ended up placing the trampoline start at physical address 0. - Handle machines which do not advertise a legacy timer of any form, but need calibration of the local APIC timer gracefully by making the calibration routine independent from the tick interrupt. Marked for stable as well as there seems to be quite some new laptops rolled out which expose this. - Clear the RDRAND CPUID bit on AMD family 15h and 16h CPUs which are affected by broken firmware which does not initialize RDRAND correctly after resume. Add a command line parameter to override this for machine which either do not use suspend/resume or have a fixed BIOS. Unfortunately there is no way to detect this on boot, so the only safe decision is to turn it off by default. - Prevent RFLAGS from being clobbers in CALL_NOSPEC on 32bit which caused fast KVM instruction emulation to break. - Explain the Intel CPU model naming convention so that the repeating discussions come to an end" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/retpoline: Don't clobber RFLAGS during CALL_NOSPEC on i386 x86/boot: Fix boot regression caused by bootparam sanitizing x86/CPU/AMD: Clear RDRAND CPUID bit on AMD family 15h/16h x86/boot/compressed/64: Fix boot on machines with broken E820 table x86/apic: Handle missing global clockevent gracefully x86/cpu: Explain Intel model naming convention
2019-08-25Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Thomas Gleixner: "Two small fixes for kprobes and perf: - Prevent a deadlock in kprobe_optimizer() causes by reverse lock ordering - Fix a comment typo" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: kprobes: Fix potential deadlock in kprobe_optimizer() perf/x86: Fix typo in comment
2019-08-23x86/retpoline: Don't clobber RFLAGS during CALL_NOSPEC on i386Sean Christopherson1-1/+1
Use 'lea' instead of 'add' when adjusting %rsp in CALL_NOSPEC so as to avoid clobbering flags. KVM's emulator makes indirect calls into a jump table of sorts, where the destination of the CALL_NOSPEC is a small blob of code that performs fast emulation by executing the target instruction with fixed operands. adcb_al_dl: 0x000339f8 <+0>: adc %dl,%al 0x000339fa <+2>: ret A major motiviation for doing fast emulation is to leverage the CPU to handle consumption and manipulation of arithmetic flags, i.e. RFLAGS is both an input and output to the target of CALL_NOSPEC. Clobbering flags results in all sorts of incorrect emulation, e.g. Jcc instructions often take the wrong path. Sans the nops... asm("push %[flags]; popf; " CALL_NOSPEC " ; pushf; pop %[flags]\n" 0x0003595a <+58>: mov 0xc0(%ebx),%eax 0x00035960 <+64>: mov 0x60(%ebx),%edx 0x00035963 <+67>: mov 0x90(%ebx),%ecx 0x00035969 <+73>: push %edi 0x0003596a <+74>: popf 0x0003596b <+75>: call *%esi 0x000359a0 <+128>: pushf 0x000359a1 <+129>: pop %edi 0x000359a2 <+130>: mov %eax,0xc0(%ebx) 0x000359b1 <+145>: mov %edx,0x60(%ebx) ctxt->eflags = (ctxt->eflags & ~EFLAGS_MASK) | (flags & EFLAGS_MASK); 0x000359a8 <+136>: mov -0x10(%ebp),%eax 0x000359ab <+139>: and $0x8d5,%edi 0x000359b4 <+148>: and $0xfffff72a,%eax 0x000359b9 <+153>: or %eax,%edi 0x000359bd <+157>: mov %edi,0x4(%ebx) For the most part this has gone unnoticed as emulation of guest code that can trigger fast emulation is effectively limited to MMIO when running on modern hardware, and MMIO is rarely, if ever, accessed by instructions that affect or consume flags. Breakage is almost instantaneous when running with unrestricted guest disabled, in which case KVM must emulate all instructions when the guest has invalid state, e.g. when the guest is in Big Real Mode during early BIOS. Fixes: 776b043848fd2 ("x86/retpoline: Add initial retpoline support") Fixes: 1a29b5b7f347a ("KVM: x86: Make indirect calls in emulator speculation safe") Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190822211122.27579-1-sean.j.christopherson@intel.com
2019-08-21x86/boot: Fix boot regression caused by bootparam sanitizingJohn Hubbard1-1/+1
commit a90118c445cc ("x86/boot: Save fields explicitly, zero out everything else") had two errors: * It preserved boot_params.acpi_rsdp_addr, and * It failed to preserve boot_params.hdr Therefore, zero out acpi_rsdp_addr, and preserve hdr. Fixes: a90118c445cc ("x86/boot: Save fields explicitly, zero out everything else") Reported-by: Neil MacLeod <neil@nmacleod.com> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Neil MacLeod <neil@nmacleod.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190821192513.20126-1-jhubbard@nvidia.com
2019-08-21Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds3-33/+6
Pull KVM fixes from Paolo Bonzini: "A couple bugfixes, and mostly selftests changes" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: selftests/kvm: make platform_info_test pass on AMD Revert "KVM: x86/mmu: Zap only the relevant pages when removing a memslot" selftests: kvm: fix state save/load on processors without XSAVE selftests: kvm: fix vmx_set_nested_state_test selftests: kvm: provide common function to enable eVMCS selftests: kvm: do not try running the VM in vmx_set_nested_state_test KVM: x86: svm: remove redundant assignment of var new_entry MAINTAINERS: add KVM x86 reviewers MAINTAINERS: change list for KVM/s390 kvm: x86: skip populating logical dest map if apic is not sw enabled
2019-08-21Revert "KVM: x86/mmu: Zap only the relevant pages when removing a memslot"Paolo Bonzini1-32/+1
This reverts commit 4e103134b862314dc2f2f18f2fb0ab972adc3f5f. Alex Williamson reported regressions with device assignment with this patch. Even though the bug is probably elsewhere and still latent, this is needed to fix the regression. Fixes: 4e103134b862 ("KVM: x86/mmu: Zap only the relevant pages when removing a memslot", 2019-02-05) Reported-by: Alex Willamson <alex.williamson@redhat.com> Cc: stable@vger.kernel.org Cc: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-08-19x86/CPU/AMD: Clear RDRAND CPUID bit on AMD family 15h/16hTom Lendacky3-13/+140
There have been reports of RDRAND issues after resuming from suspend on some AMD family 15h and family 16h systems. This issue stems from a BIOS not performing the proper steps during resume to ensure RDRAND continues to function properly. RDRAND support is indicated by CPUID Fn00000001_ECX[30]. This bit can be reset by clearing MSR C001_1004[62]. Any software that checks for RDRAND support using CPUID, including the kernel, will believe that RDRAND is not supported. Update the CPU initialization to clear the RDRAND CPUID bit for any family 15h and 16h processor that supports RDRAND. If it is known that the family 15h or family 16h system does not have an RDRAND resume issue or that the system will not be placed in suspend, the "rdrand=force" kernel parameter can be used to stop the clearing of the RDRAND CPUID bit. Additionally, update the suspend and resume path to save and restore the MSR C001_1004 value to ensure that the RDRAND CPUID setting remains in place after resuming from suspend. Note, that clearing the RDRAND CPUID bit does not prevent a processor that normally supports the RDRAND instruction from executing it. So any code that determined the support based on family and model won't #UD. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chen Yu <yu.c.chen@intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Kees Cook <keescook@chromium.org> Cc: "linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org> Cc: "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org> Cc: Nathan Chancellor <natechancellor@gmail.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: <stable@vger.kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "x86@kernel.org" <x86@kernel.org> Link: https://lkml.kernel.org/r/7543af91666f491547bd86cebb1e17c66824ab9f.1566229943.git.thomas.lendacky@amd.com
2019-08-19Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netLinus Torvalds1-4/+5
Pull networking fixes from David Miller: 1) Fix jmp to 1st instruction in x64 JIT, from Alexei Starovoitov. 2) Severl kTLS fixes in mlx5 driver, from Tariq Toukan. 3) Fix severe performance regression due to lack of SKB coalescing of fragments during local delivery, from Guillaume Nault. 4) Error path memory leak in sch_taprio, from Ivan Khoronzhuk. 5) Fix batched events in skbedit packet action, from Roman Mashak. 6) Propagate VLAN TX offload to hw_enc_features in bond and team drivers, from Yue Haibing. 7) RXRPC local endpoint refcounting fix and read after free in rxrpc_queue_local(), from David Howells. 8) Fix endian bug in ibmveth multicast list handling, from Thomas Falcon. 9) Oops, make nlmsg_parse() wrap around the correct function, __nlmsg_parse not __nla_parse(). Fix from David Ahern. 10) Memleak in sctp_scend_reset_streams(), fro Zheng Bin. 11) Fix memory leak in cxgb4, from Wenwen Wang. 12) Yet another race in AF_PACKET, from Eric Dumazet. 13) Fix false detection of retransmit failures in tipc, from Tuong Lien. 14) Use after free in ravb_tstamp_skb, from Tho Vu. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (101 commits) ravb: Fix use-after-free ravb_tstamp_skb netfilter: nf_tables: map basechain priority to hardware priority net: sched: use major priority number as hardware priority wimax/i2400m: fix a memory leak bug net: cavium: fix driver name ibmvnic: Unmap DMA address of TX descriptor buffers after use bnxt_en: Fix to include flow direction in L2 key bnxt_en: Use correct src_fid to determine direction of the flow bnxt_en: Suppress HWRM errors for HWRM_NVM_GET_VARIABLE command bnxt_en: Fix handling FRAG_ERR when NVM_INSTALL_UPDATE cmd fails bnxt_en: Improve RX doorbell sequence. bnxt_en: Fix VNIC clearing logic for 57500 chips. net: kalmia: fix memory leaks cx82310_eth: fix a memory leak bug bnx2x: Fix VF's VLAN reconfiguration in reload. Bluetooth: Add debug setting for changing minimum encryption key size tipc: fix false detection of retransmit failures lan78xx: Fix memory leaks MAINTAINERS: r8169: Update path to the driver MAINTAINERS: PHY LIBRARY: Update files in the record ...
2019-08-19x86/boot/compressed/64: Fix boot on machines with broken E820 tableKirill A. Shutemov1-3/+10
BIOS on Samsung 500C Chromebook reports very rudimentary E820 table that consists of 2 entries: BIOS-e820: [mem 0x0000000000000000-0x0000000000000fff] usable BIOS-e820: [mem 0x00000000fffff000-0x00000000ffffffff] reserved It breaks logic in find_trampoline_placement(): bios_start lands on the end of the first 4k page and trampoline start gets placed below 0. Detect underflow and don't touch bios_start for such cases. It makes kernel ignore E820 table on machines that doesn't have two usable pages below BIOS_START_MAX. Fixes: 1b3a62643660 ("x86/boot/compressed/64: Validate trampoline placement against E820") Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86-ml <x86@kernel.org> Link: https://bugzilla.kernel.org/show_bug.cgi?id=203463 Link: https://lkml.kernel.org/r/20190813131654.24378-1-kirill.shutemov@linux.intel.com
2019-08-19x86/apic: Handle missing global clockevent gracefullyThomas Gleixner1-15/+53
Some newer machines do not advertise legacy timers. The kernel can handle that situation if the TSC and the CPU frequency are enumerated by CPUID or MSRs and the CPU supports TSC deadline timer. If the CPU does not support TSC deadline timer the local APIC timer frequency has to be known as well. Some Ryzens machines do not advertize legacy timers, but there is no reliable way to determine the bus frequency which feeds the local APIC timer when the machine allows overclocking of that frequency. As there is no legacy timer the local APIC timer calibration crashes due to a NULL pointer dereference when accessing the not installed global clock event device. Switch the calibration loop to a non interrupt based one, which polls either TSC (if frequency is known) or jiffies. The latter requires a global clockevent. As the machines which do not have a global clockevent installed have a known TSC frequency this is a non issue. For older machines where TSC frequency is not known, there is no known case where the legacy timers do not exist as that would have been reported long ago. Reported-by: Daniel Drake <drake@endlessm.com> Reported-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Daniel Drake <drake@endlessm.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1908091443030.21433@nanos.tec.linutronix.de Link: http://bugzilla.opensuse.org/show_bug.cgi?id=1142926#c12
2019-08-19perf/x86: Fix typo in commentSu Yanjun1-1/+1
No functional change. Signed-off-by: Su Yanjun <suyj.fnst@cn.fujitsu.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1565945001-4413-1-git-send-email-suyj.fnst@cn.fujitsu.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-08-17x86/cpu: Explain Intel model naming conventionTony Luck1-0/+15
Dave Hansen spelled out the rules in an e-mail: https://lkml.kernel.org/r/91eefbe4-e32b-d762-be4d-672ff915db47@intel.com Copy those right into the <asm/intel-family.h> file to make it easy for people to find them. Suggested-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190815224704.GA10025@agluck-desk2.amr.corp.intel.com
2019-08-16x86/boot: Save fields explicitly, zero out everything elseJohn Hubbard1-15/+48
Recent gcc compilers (gcc 9.1) generate warnings about an out of bounds memset, if the memset goes accross several fields of a struct. This generated a couple of warnings on x86_64 builds in sanitize_boot_params(). Fix this by explicitly saving the fields in struct boot_params that are intended to be preserved, and zeroing all the rest. [ tglx: Tagged for stable as it breaks the warning free build there as well ] Suggested-by: Thomas Gleixner <tglx@linutronix.de> Suggested-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190731054627.5627-2-jhubbard@nvidia.com
2019-08-14KVM: x86: svm: remove redundant assignment of var new_entryMiaohe Lin1-1/+0
new_entry is reassigned a new value next line. So it's redundant and remove it. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-08-14kvm: x86: skip populating logical dest map if apic is not sw enabledRadim Krcmar1-0/+5
recalculate_apic_map does not santize ldr and it's possible that multiple bits are set. In that case, a previous valid entry can potentially be overwritten by an invalid one. This condition is hit when booting a 32 bit, >8 CPU, RHEL6 guest and then triggering a crash to boot a kdump kernel. This is the sequence of events: 1. Linux boots in bigsmp mode and enables PhysFlat, however, it still writes to the LDR which probably will never be used. 2. However, when booting into kdump, the stale LDR values remain as they are not cleared by the guest and there isn't a apic reset. 3. kdump boots with 1 cpu, and uses Logical Destination Mode but the logical map has been overwritten and points to an inactive vcpu. Signed-off-by: Radim Krcmar <rkrcmar@redhat.com> Signed-off-by: Bandan Das <bsd@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-08-12x86/fpu/math-emu: Address fallthrough warningsThomas Gleixner2-3/+4
/home/tglx/work/kernel/linus/linux/arch/x86/math-emu/errors.c: In function ‘FPU_printall’: /home/tglx/work/kernel/linus/linux/arch/x86/math-emu/errors.c:187:9: warning: this statement may fall through [-Wimplicit-fallthrough=] tagi = FPU_Special(r); ~~~~~^~~~~~~~~~~~~~~~ /home/tglx/work/kernel/linus/linux/arch/x86/math-emu/errors.c:188:3: note: here case TAG_Valid: ^~~~ /home/tglx/work/kernel/linus/linux/arch/x86/math-emu/fpu_trig.c: In function ‘fyl2xp1’: /home/tglx/work/kernel/linus/linux/arch/x86/math-emu/fpu_trig.c:1353:7: warning: this statement may fall through [-Wimplicit-fallthrough=] if (denormal_operand() < 0) ^ /home/tglx/work/kernel/linus/linux/arch/x86/math-emu/fpu_trig.c:1356:3: note: here case TAG_Zero: Remove the pointless 'break;' after 'continue;' while at it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2019-08-12x86/apic/32: Fix yet another implicit fallthrough warningBorislav Petkov1-1/+2
Fix arch/x86/kernel/apic/probe_32.c: In function ‘default_setup_apic_routing’: arch/x86/kernel/apic/probe_32.c:146:7: warning: this statement may fall through [-Wimplicit-fallthrough=] if (!APIC_XAPIC(version)) { ^ arch/x86/kernel/apic/probe_32.c:151:3: note: here case X86_VENDOR_HYGON: ^~~~ for 32-bit builds. Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190811154036.29805-1-bp@alien8.de
2019-08-12x86/umwait: Fix error handling in umwait_init()Fenghua Yu1-1/+38
Currently, failure of cpuhp_setup_state() is ignored and the syscore ops and the control interfaces can still be added even after the failure. But, this error handling will cause a few issues: 1. The CPUs may have different values in the IA32_UMWAIT_CONTROL MSR because there is no way to roll back the control MSR on the CPUs which already set the MSR before the failure. 2. If the sysfs interface is added successfully, there will be a mismatch between the global control value and the control MSR: - The interface shows the default global control value. But, the control MSR is not set to the value because the CPU online function, which is supposed to set the MSR to the value, is not installed. - If the sysadmin changes the global control value through the interface, the control MSR on all current online CPUs is set to the new value. But, the control MSR on newly onlined CPUs after the value change will not be set to the new value due to lack of the CPU online function. 3. On resume from suspend/hibernation, the boot CPU restores the control MSR to the global control value through the syscore ops. But, the control MSR on all APs is not set due to lake of the CPU online function. To solve the issues and enforce consistent behavior on the failure of the CPU hotplug setup, make the following changes: 1. Cache the original control MSR value which is configured by hardware or BIOS before kernel boot. This value is likely to be 0. But it could be a different number as well. Cache the control MSR only once before the MSR is changed. 2. Add the CPU offline function so that the MSR is restored to the original control value on all CPUs on the failure. 3. On the failure, exit from cpumait_init() so that the syscore ops and the control interfaces are not added. Reported-by: Valdis Kletnieks <valdis.kletnieks@vt.edu> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/1565401237-60936-1-git-send-email-fenghua.yu@intel.com
2019-08-11Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpfDavid S. Miller1-4/+5
Daniel Borkmann says: ==================== pull-request: bpf 2019-08-11 The following pull-request contains BPF updates for your *net* tree. The main changes are: 1) x64 JIT code generation fix for backward-jumps to 1st insn, from Alexei. 2) Fix buggy multi-closing of BTF file descriptor in libbpf, from Andrii. 3) Fix libbpf_num_possible_cpus() to make it thread safe, from Takshak. 4) Fix bpftool to dump an error if pinning fails, from Jakub. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-10Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds7-28/+48
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Thomas Gleixner: "A few fixes for x86: - Don't reset the carefully adjusted build flags for the purgatory and remove the unwanted flags instead. The 'reset all' approach led to build fails under certain circumstances. - Unbreak CLANG build of the purgatory by avoiding the builtin memcpy/memset implementations. - Address missing prototype warnings by including the proper header - Fix yet more fall-through issues" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/lib/cpu: Address missing prototypes warning x86/purgatory: Use CFLAGS_REMOVE rather than reset KBUILD_CFLAGS x86/purgatory: Do not use __builtin_memcpy and __builtin_memset x86: mtrr: cyrix: Mark expected switch fall-through x86/ptrace: Mark expected switch fall-through
2019-08-09Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds7-49/+44
Pull kvm fixes from Paolo Bonzini: "Bugfixes (arm and x86) and cleanups" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: selftests: kvm: Adding config fragments KVM: selftests: Update gitignore file for latest changes kvm: remove unnecessary PageReserved check KVM: arm/arm64: vgic: Reevaluate level sensitive interrupts on enable KVM: arm: Don't write junk to CP15 registers on reset KVM: arm64: Don't write junk to sysregs on reset KVM: arm/arm64: Sync ICH_VMCR_EL2 back when about to block x86: kvm: remove useless calls to kvm_para_available KVM: no need to check return value of debugfs_create functions KVM: remove kvm_arch_has_vcpu_debugfs() KVM: Fix leak vCPU's VMCS value into other pCPU KVM: Check preempted_in_kernel for involuntary preemption KVM: LAPIC: Don't need to wakeup vCPU twice afer timer fire arm64: KVM: hyp: debug-sr: Mark expected switch fall-through KVM: arm64: Update kvm_arm_exception_class and esr_class_str for new EC KVM: arm: vgic-v3: Mark expected switch fall-through arm64: KVM: regmap: Fix unexpected switch fall-through KVM: arm/arm64: Introduce kvm_pmu_vcpu_init() to setup PMU counter index
2019-08-09Merge tag 'kvmarm-fixes-for-5.3' of ↵Paolo Bonzini68-504/+493
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm fixes for 5.3 - A bunch of switch/case fall-through annotation, fixing one actual bug - Fix PMU reset bug - Add missing exception class debug strings
2019-08-08x86/lib/cpu: Address missing prototypes warningValdis Klētnieks1-0/+1
When building with W=1, warnings about missing prototypes are emitted: CC arch/x86/lib/cpu.o arch/x86/lib/cpu.c:5:14: warning: no previous prototype for 'x86_family' [-Wmissing-prototypes] 5 | unsigned int x86_family(unsigned int sig) | ^~~~~~~~~~ arch/x86/lib/cpu.c:18:14: warning: no previous prototype for 'x86_model' [-Wmissing-prototypes] 18 | unsigned int x86_model(unsigned int sig) | ^~~~~~~~~ arch/x86/lib/cpu.c:33:14: warning: no previous prototype for 'x86_stepping' [-Wmissing-prototypes] 33 | unsigned int x86_stepping(unsigned int sig) | ^~~~~~~~~~~~ Add the proper include file so the prototypes are there. Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/42513.1565234837@turing-police
2019-08-08x86/purgatory: Use CFLAGS_REMOVE rather than reset KBUILD_CFLAGSNick Desaulniers1-5/+28
KBUILD_CFLAGS is very carefully built up in the top level Makefile, particularly when cross compiling or using different build tools. Resetting KBUILD_CFLAGS via := assignment is an antipattern. The comment above the reset mentions that -pg is problematic. Other Makefiles use `CFLAGS_REMOVE_file.o = $(CC_FLAGS_FTRACE)` when CONFIG_FUNCTION_TRACER is set. Prefer that pattern to wiping out all of the important KBUILD_CFLAGS then manually having to re-add them. Seems also that __stack_chk_fail references are generated when using CONFIG_STACKPROTECTOR or CONFIG_STACKPROTECTOR_STRONG. Fixes: 8fc5b4d4121c ("purgatory: core purgatory functionality") Reported-by: Vaibhav Rustagi <vaibhavrustagi@google.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Vaibhav Rustagi <vaibhavrustagi@google.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190807221539.94583-2-ndesaulniers@google.com
2019-08-08x86/purgatory: Do not use __builtin_memcpy and __builtin_memsetNick Desaulniers4-23/+17
Implementing memcpy and memset in terms of __builtin_memcpy and __builtin_memset is problematic. GCC at -O2 will replace calls to the builtins with calls to memcpy and memset (but will generate an inline implementation at -Os). Clang will replace the builtins with these calls regardless of optimization level. $ llvm-objdump -dr arch/x86/purgatory/string.o | tail 0000000000000339 memcpy: 339: 48 b8 00 00 00 00 00 00 00 00 movabsq $0, %rax 000000000000033b: R_X86_64_64 memcpy 343: ff e0 jmpq *%rax 0000000000000345 memset: 345: 48 b8 00 00 00 00 00 00 00 00 movabsq $0, %rax 0000000000000347: R_X86_64_64 memset 34f: ff e0 Such code results in infinite recursion at runtime. This is observed when doing kexec. Instead, reuse an implementation from arch/x86/boot/compressed/string.c. This requires to implement a stub function for warn(). Also, Clang may lower memcmp's that compare against 0 to bcmp's, so add a small definition, too. See also: commit 5f074f3e192f ("lib/string.c: implement a basic bcmp") Fixes: 8fc5b4d4121c ("purgatory: core purgatory functionality") Reported-by: Vaibhav Rustagi <vaibhavrustagi@google.com> Debugged-by: Vaibhav Rustagi <vaibhavrustagi@google.com> Debugged-by: Manoj Gupta <manojgupta@google.com> Suggested-by: Alistair Delva <adelva@google.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Vaibhav Rustagi <vaibhavrustagi@google.com> Cc: stable@vger.kernel.org Link: https://bugs.chromium.org/p/chromium/issues/detail?id=984056 Link: https://lkml.kernel.org/r/20190807221539.94583-1-ndesaulniers@google.com
2019-08-07x86: mtrr: cyrix: Mark expected switch fall-throughGustavo A. R. Silva1-0/+1
Mark switch cases where we are expecting to fall through. Fix the following warning (Building: i386_defconfig i386): arch/x86/kernel/cpu/mtrr/cyrix.c:99:6: warning: this statement may fall through [-Wimplicit-fallthrough=] Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20190805201712.GA19927@embeddedor
2019-08-07x86/ptrace: Mark expected switch fall-throughGustavo A. R. Silva1-0/+1
Mark switch cases where we are expecting to fall through. Fix the following warning (Building: allnoconfig i386): arch/x86/kernel/ptrace.c:202:6: warning: this statement may fall through [-Wimplicit-fallthrough=] if (unlikely(value == 0)) ^ arch/x86/kernel/ptrace.c:206:2: note: here default: ^~~~~~~ Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20190805195654.GA17831@embeddedor
2019-08-06Merge branch 'x86/grand-schemozzle' of ↵Linus Torvalds5-28/+162
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull pti updates from Thomas Gleixner: "The performance deterioration departement is not proud at all to present yet another set of speculation fences to mitigate the next chapter in the 'what could possibly go wrong' story. The new vulnerability belongs to the Spectre class and affects GS based data accesses and has therefore been dubbed 'Grand Schemozzle' for secret communication purposes. It's officially listed as CVE-2019-1125. Conditional branches in the entry paths which contain a SWAPGS instruction (interrupts and exceptions) can be mis-speculated which results in speculative accesses with a wrong GS base. This can happen on entry from user mode through a mis-speculated branch which takes the entry from kernel mode path and therefore does not execute the SWAPGS instruction. The following speculative accesses are done with user GS base. On entry from kernel mode the mis-speculated branch executes the SWAPGS instruction in the entry from user mode path which has the same effect that the following GS based accesses are done with user GS base. If there is a disclosure gadget available in these code paths the mis-speculated data access can be leaked through the usual side channels. The entry from user mode issue affects all CPUs which have speculative execution. The entry from kernel mode issue affects only Intel CPUs which can speculate through SWAPGS. On CPUs from other vendors SWAPGS has semantics which prevent that. SMAP migitates both problems but only when the CPU is not affected by the Meltdown vulnerability. The mitigation is to issue LFENCE instructions in the entry from kernel mode path for all affected CPUs and on the affected Intel CPUs also in the entry from user mode path unless PTI is enabled because the CR3 write is serializing. The fences are as usual enabled conditionally and can be completely disabled on the kernel command line. The Spectre V1 documentation is updated accordingly. A big "Thank You!" goes to Josh for doing the heavy lifting for this round of hardware misfeature 'repair'. Of course also "Thank You!" to everybody else who contributed in one way or the other" * 'x86/grand-schemozzle' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Documentation: Add swapgs description to the Spectre v1 documentation x86/speculation/swapgs: Exclude ATOMs from speculation through SWAPGS x86/entry/64: Use JMP instead of JMPQ x86/speculation: Enable Spectre v1 swapgs mitigations x86/speculation: Prepare entry code for Spectre v1 swapgs mitigations
2019-08-05x86: kvm: remove useless calls to kvm_para_availablePaolo Bonzini1-8/+0
Most code in arch/x86/kernel/kvm.c is called through x86_hyper_kvm, and thus only runs if KVM has been detected. There is no need to check again for the CPUID base. Cc: Sergio Lopez <slp@redhat.com> Cc: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-08-05KVM: no need to check return value of debugfs_create functionsGreg KH1-28/+13
When calling debugfs functions, there is no need to ever check the return value. The function can work or not, but the code logic should never do something different based on this. Also, when doing this, change kvm_arch_create_vcpu_debugfs() to return void instead of an integer, as we should not care at all about if this function actually does anything or not. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: <x86@kernel.org> Cc: <kvm@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-08-05KVM: remove kvm_arch_has_vcpu_debugfs()Paolo Bonzini2-5/+2
There is no need for this function as all arches have to implement kvm_arch_create_vcpu_debugfs() no matter what. A #define symbol let us actually simplify the code. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-08-05KVM: Fix leak vCPU's VMCS value into other pCPUWanpeng Li4-0/+29
After commit d73eb57b80b (KVM: Boost vCPUs that are delivering interrupts), a five years old bug is exposed. Running ebizzy benchmark in three 80 vCPUs VMs on one 80 pCPUs Skylake server, a lot of rcu_sched stall warning splatting in the VMs after stress testing: INFO: rcu_sched detected stalls on CPUs/tasks: { 4 41 57 62 77} (detected by 15, t=60004 jiffies, g=899, c=898, q=15073) Call Trace: flush_tlb_mm_range+0x68/0x140 tlb_flush_mmu.part.75+0x37/0xe0 tlb_finish_mmu+0x55/0x60 zap_page_range+0x142/0x190 SyS_madvise+0x3cd/0x9c0 system_call_fastpath+0x1c/0x21 swait_active() sustains to be true before finish_swait() is called in kvm_vcpu_block(), voluntarily preempted vCPUs are taken into account by kvm_vcpu_on_spin() loop greatly increases the probability condition kvm_arch_vcpu_runnable(vcpu) is checked and can be true, when APICv is enabled the yield-candidate vCPU's VMCS RVI field leaks(by vmx_sync_pir_to_irr()) into spinning-on-a-taken-lock vCPU's current VMCS. This patch fixes it by checking conservatively a subset of events. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Marc Zyngier <Marc.Zyngier@arm.com> Cc: stable@vger.kernel.org Fixes: 98f4a1467 (KVM: add kvm_arch_vcpu_runnable() test to kvm_vcpu_on_spin() loop) Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-08-05KVM: LAPIC: Don't need to wakeup vCPU twice afer timer fireWanpeng Li1-8/+0
kvm_set_pending_timer() will take care to wake up the sleeping vCPU which has pending timer, don't need to check this in apic_timer_expired() again. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-08-01bpf: fix x64 JIT code generation for jmp to 1st insnAlexei Starovoitov1-4/+5
Introduction of bounded loops exposed old bug in x64 JIT. JIT maintains the array of offsets to the end of all instructions to compute jmp offsets. addrs[0] - offset of the end of the 1st insn (that includes prologue). addrs[1] - offset of the end of the 2nd insn. JIT didn't keep the offset of the beginning of the 1st insn, since classic BPF didn't have backward jumps and valid extended BPF couldn't have a branch to 1st insn, because it didn't allow loops. With bounded loops it's possible to construct a valid program that jumps backwards to the 1st insn. Fix JIT by computing: addrs[0] - offset of the end of prologue == start of the 1st insn. addrs[1] - offset of the end of 1st insn. v1->v2: - Yonghong noticed a bug in jit linfo. Fix it by passing 'addrs + 1' to bpf_prog_fill_jited_linfo(), since it expects insn_to_jit_off array to be offsets to last byte. Reported-by: syzbot+35101610ff3e83119b1b@syzkaller.appspotmail.com Fixes: 2589726d12a1 ("bpf: introduce bounded loops") Fixes: 0a14842f5a3c ("net: filter: Just In Time compiler for x86-64") Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com>
2019-07-31x86/vdso/32: Use 32bit syscall fallbackThomas Gleixner1-0/+36
The generic VDSO implementation uses the Y2038 safe clock_gettime64() and clock_getres_time64() syscalls as fallback for 32bit VDSO. This breaks seccomp setups because these syscalls might be not (yet) allowed. Implement the 32bit variants which use the legacy syscalls and select the variant in the core library. The 64bit time variants are not removed because they are required for the time64 based vdso accessors. Fixes: 7ac870747988 ("x86/vdso: Switch to generic vDSO implementation") Reported-by: Sean Christopherson <sean.j.christopherson@intel.com> Reported-by: Paul Bolle <pebolle@tiscali.nl> Suggested-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Andy Lutomirski <luto@kernel.org> Link: https://lkml.kernel.org/r/20190728131648.879156507@linutronix.de
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