1. 16 5月, 2018 2 次提交
  2. 15 5月, 2018 1 次提交
    • C
      arm64: Increase ARCH_DMA_MINALIGN to 128 · ebc7e21e
      Catalin Marinas 提交于
      This patch increases the ARCH_DMA_MINALIGN to 128 so that it covers the
      currently known Cache Writeback Granule (CTR_EL0.CWG) on arm64 and moves
      the fallback in cache_line_size() from L1_CACHE_BYTES to this constant.
      In addition, it warns (and taints) if the CWG is larger than
      ARCH_DMA_MINALIGN as this is not safe with non-coherent DMA.
      
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Robin Murphy <robin.murphy@arm.com>
      Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
      ebc7e21e
  3. 11 5月, 2018 1 次提交
    • C
      Revert "arm64: Increase the max granular size" · d93277b9
      Catalin Marinas 提交于
      This reverts commit 97303480.
      
      Commit 97303480 ("arm64: Increase the max granular size") increased
      the cache line size to 128 to match Cavium ThunderX, apparently for some
      performance benefit which could not be confirmed. This change, however,
      has an impact on the network packet allocation in certain circumstances,
      requiring slightly over a 4K page with a significant performance
      degradation. The patch reverts L1_CACHE_SHIFT back to 6 (64-byte cache
      line).
      
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Robin Murphy <robin.murphy@arm.com>
      Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
      d93277b9
  4. 06 5月, 2018 1 次提交
    • A
      KVM: x86: remove APIC Timer periodic/oneshot spikes · ecf08dad
      Anthoine Bourgeois 提交于
      Since the commit "8003c9ae: add APIC Timer periodic/oneshot mode VMX
      preemption timer support", a Windows 10 guest has some erratic timer
      spikes.
      
      Here the results on a 150000 times 1ms timer without any load:
      	  Before 8003c9ae | After 8003c9ae
      Max           1834us          |  86000us
      Mean          1100us          |   1021us
      Deviation       59us          |    149us
      Here the results on a 150000 times 1ms timer with a cpu-z stress test:
      	  Before 8003c9ae | After 8003c9ae
      Max          32000us          | 140000us
      Mean          1006us          |   1997us
      Deviation      140us          |  11095us
      
      The root cause of the problem is starting hrtimer with an expiry time
      already in the past can take more than 20 milliseconds to trigger the
      timer function.  It can be solved by forward such past timers
      immediately, rather than submitting them to hrtimer_start().
      In case the timer is periodic, update the target expiration and call
      hrtimer_start with it.
      
      v2: Check if the tsc deadline is already expired. Thank you Mika.
      v3: Execute the past timers immediately rather than submitting them to
      hrtimer_start().
      v4: Rearm the periodic timer with advance_periodic_target_expiration() a
      simpler version of set_target_expiration(). Thank you Paolo.
      
      Cc: Mika Penttilä <mika.penttila@nextfour.com>
      Cc: Wanpeng Li <kernellwp@gmail.com>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: stable@vger.kernel.org
      Signed-off-by: NAnthoine Bourgeois <anthoine.bourgeois@blade-group.com>
      8003c9ae ("KVM: LAPIC: add APIC Timer periodic/oneshot mode VMX preemption timer support")
      Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      ecf08dad
  5. 04 5月, 2018 2 次提交
    • J
      arm64: vgic-v2: Fix proxying of cpuif access · b220244d
      James Morse 提交于
      Proxying the cpuif accesses at EL2 makes use of vcpu_data_guest_to_host
      and co, which check the endianness, which call into vcpu_read_sys_reg...
      which isn't mapped at EL2 (it was inlined before, and got moved OoL
      with the VHE optimizations).
      
      The result is of course a nice panic. Let's add some specialized
      cruft to keep the broken platforms that require this hack alive.
      
      But, this code used vcpu_data_guest_to_host(), which expected us to
      write the value to host memory, instead we have trapped the guest's
      read or write to an mmio-device, and are about to replay it using the
      host's readl()/writel() which also perform swabbing based on the host
      endianness. This goes wrong when both host and guest are big-endian,
      as readl()/writel() will undo the guest's swabbing, causing the
      big-endian value to be written to device-memory.
      
      What needs doing?
      A big-endian guest will have pre-swabbed data before storing, undo this.
      If its necessary for the host, writel() will re-swab it.
      
      For a read a big-endian guest expects to swab the data after the load.
      The hosts's readl() will correct for host endianness, giving us the
      device-memory's value in the register. For a big-endian guest, swab it
      as if we'd only done the load.
      
      For a little-endian guest, nothing needs doing as readl()/writel() leave
      the correct device-memory value in registers.
      
      Tested on Juno with that rarest of things: a big-endian 64K host.
      Based on a patch from Marc Zyngier.
      Reported-by: NSuzuki K Poulose <suzuki.poulose@arm.com>
      Fixes: bf8feb39 ("arm64: KVM: vgic-v2: Add GICV access from HYP")
      Signed-off-by: NJames Morse <james.morse@arm.com>
      Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
      b220244d
    • J
      KVM: arm64: Fix order of vcpu_write_sys_reg() arguments · 1975fa56
      James Morse 提交于
      A typo in kvm_vcpu_set_be()'s call:
      | vcpu_write_sys_reg(vcpu, SCTLR_EL1, sctlr)
      causes us to use the 32bit register value as an index into the sys_reg[]
      array, and sail off the end of the linear map when we try to bring up
      big-endian secondaries.
      
      | Unable to handle kernel paging request at virtual address ffff80098b982c00
      | Mem abort info:
      |  ESR = 0x96000045
      |  Exception class = DABT (current EL), IL = 32 bits
      |   SET = 0, FnV = 0
      |   EA = 0, S1PTW = 0
      | Data abort info:
      |   ISV = 0, ISS = 0x00000045
      |   CM = 0, WnR = 1
      | swapper pgtable: 4k pages, 48-bit VAs, pgdp = 000000002ea0571a
      | [ffff80098b982c00] pgd=00000009ffff8803, pud=0000000000000000
      | Internal error: Oops: 96000045 [#1] PREEMPT SMP
      | Modules linked in:
      | CPU: 2 PID: 1561 Comm: kvm-vcpu-0 Not tainted 4.17.0-rc3-00001-ga912e2261ca6-dirty #1323
      | Hardware name: ARM Juno development board (r1) (DT)
      | pstate: 60000005 (nZCv daif -PAN -UAO)
      | pc : vcpu_write_sys_reg+0x50/0x134
      | lr : vcpu_write_sys_reg+0x50/0x134
      
      | Process kvm-vcpu-0 (pid: 1561, stack limit = 0x000000006df4728b)
      | Call trace:
      |  vcpu_write_sys_reg+0x50/0x134
      |  kvm_psci_vcpu_on+0x14c/0x150
      |  kvm_psci_0_2_call+0x244/0x2a4
      |  kvm_hvc_call_handler+0x1cc/0x258
      |  handle_hvc+0x20/0x3c
      |  handle_exit+0x130/0x1ec
      |  kvm_arch_vcpu_ioctl_run+0x340/0x614
      |  kvm_vcpu_ioctl+0x4d0/0x840
      |  do_vfs_ioctl+0xc8/0x8d0
      |  ksys_ioctl+0x78/0xa8
      |  sys_ioctl+0xc/0x18
      |  el0_svc_naked+0x30/0x34
      | Code: 73620291 604d00b0 00201891 1ab10194 (957a33f8)
      |---[ end trace 4b4a4f9628596602 ]---
      
      Fix the order of the arguments.
      
      Fixes: 8d404c4c ("KVM: arm64: Rewrite system register accessors to read/write functions")
      CC: Christoffer Dall <cdall@cs.columbia.edu>
      Signed-off-by: NJames Morse <james.morse@arm.com>
      Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
      1975fa56
  6. 03 5月, 2018 4 次提交
    • H
      parisc: Fix section mismatches · 8d73b180
      Helge Deller 提交于
      Fix three section mismatches:
      1) Section mismatch in reference from the function ioread8() to the
         function .init.text:pcibios_init_bridge()
      2) Section mismatch in reference from the function free_initmem() to the
         function .init.text:map_pages()
      3) Section mismatch in reference from the function ccio_ioc_init() to
         the function .init.text:count_parisc_driver()
      Signed-off-by: NHelge Deller <deller@gmx.de>
      8d73b180
    • H
      parisc: drivers.c: Fix section mismatches · b819439f
      Helge Deller 提交于
      Fix two section mismatches in drivers.c:
      1) Section mismatch in reference from the function alloc_tree_node() to
         the function .init.text:create_tree_node().
      2) Section mismatch in reference from the function walk_native_bus() to
         the function .init.text:alloc_pa_dev().
      Signed-off-by: NHelge Deller <deller@gmx.de>
      b819439f
    • D
      bpf, x64: fix memleak when not converging on calls · 39f56ca9
      Daniel Borkmann 提交于
      The JIT logic in jit_subprogs() is as follows: for all subprogs we
      allocate a bpf_prog_alloc(), populate it (prog->is_func = 1 here),
      and pass it to bpf_int_jit_compile(). If a failure occurred during
      JIT and prog->jited is not set, then we bail out from attempting to
      JIT the whole program, and punt to the interpreter instead. In case
      JITing went successful, we fixup BPF call offsets and do another
      pass to bpf_int_jit_compile() (extra_pass is true at that point) to
      complete JITing calls. Given that requires to pass JIT context around
      addrs and jit_data from x86 JIT are freed in the extra_pass in
      bpf_int_jit_compile() when calls are involved (if not, they can
      be freed immediately). However, if in the original pass, the JIT
      image didn't converge then we leak addrs and jit_data since image
      itself is NULL, the prog->is_func is set and extra_pass is false
      in that case, meaning both will become unreachable and are never
      cleaned up, therefore we need to free as well on !image. Only x64
      JIT is affected.
      
      Fixes: 1c2a088a ("bpf: x64: add JIT support for multi-function programs")
      Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      Acked-by: NAlexei Starovoitov <ast@kernel.org>
      Acked-by: NDavid S. Miller <davem@davemloft.net>
      Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
      39f56ca9
    • D
      bpf, x64: fix memleak when not converging after image · 3aab8884
      Daniel Borkmann 提交于
      While reviewing x64 JIT code, I noticed that we leak the prior allocated
      JIT image in the case where proglen != oldproglen during the JIT passes.
      Prior to the commit e0ee9c12 ("x86: bpf_jit: fix two bugs in eBPF JIT
      compiler") we would just break out of the loop, and using the image as the
      JITed prog since it could only shrink in size anyway. After e0ee9c12,
      we would bail out to out_addrs label where we free addrs and jit_data but
      not the image coming from bpf_jit_binary_alloc().
      
      Fixes: e0ee9c12 ("x86: bpf_jit: fix two bugs in eBPF JIT compiler")
      Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      Acked-by: NAlexei Starovoitov <ast@kernel.org>
      Acked-by: NDavid S. Miller <davem@davemloft.net>
      Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
      3aab8884
  7. 02 5月, 2018 5 次提交
  8. 01 5月, 2018 2 次提交
  9. 28 4月, 2018 1 次提交
  10. 27 4月, 2018 8 次提交
    • J
      kvm: apic: Flush TLB after APIC mode/address change if VPIDs are in use · a468f2db
      Junaid Shahid 提交于
      Currently, KVM flushes the TLB after a change to the APIC access page
      address or the APIC mode when EPT mode is enabled. However, even in
      shadow paging mode, a TLB flush is needed if VPIDs are being used, as
      specified in the Intel SDM Section 29.4.5.
      
      So replace vmx_flush_tlb_ept_only() with vmx_flush_tlb(), which will
      flush if either EPT or VPIDs are in use.
      Signed-off-by: NJunaid Shahid <junaids@google.com>
      Reviewed-by: NJim Mattson <jmattson@google.com>
      Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      a468f2db
    • A
      x86/entry/64/compat: Preserve r8-r11 in int $0x80 · 8bb2610b
      Andy Lutomirski 提交于
      32-bit user code that uses int $80 doesn't care about r8-r11.  There is,
      however, some 64-bit user code that intentionally uses int $0x80 to invoke
      32-bit system calls.  From what I've seen, basically all such code assumes
      that r8-r15 are all preserved, but the kernel clobbers r8-r11.  Since I
      doubt that there's any code that depends on int $0x80 zeroing r8-r11,
      change the kernel to preserve them.
      
      I suspect that very little user code is broken by the old clobber, since
      r8-r11 are only rarely allocated by gcc, and they're clobbered by function
      calls, so they only way we'd see a problem is if the same function that
      invokes int $0x80 also spills something important to one of these
      registers.
      
      The current behavior seems to date back to the historical commit
      "[PATCH] x86-64 merge for 2.6.4".  Before that, all regs were
      preserved.  I can't find any explanation of why this change was made.
      
      Update the test_syscall_vdso_32 testcase as well to verify the new
      behavior, and it strengthens the test to make sure that the kernel doesn't
      accidentally permute r8..r15.
      Suggested-by: NDenys Vlasenko <dvlasenk@redhat.com>
      Signed-off-by: NAndy Lutomirski <luto@kernel.org>
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Dominik Brodowski <linux@dominikbrodowski.net>
      Link: https://lkml.kernel.org/r/d4c4d9985fbe64f8c9e19291886453914b48caee.1523975710.git.luto@kernel.org
      8bb2610b
    • A
      x86/ipc: Fix x32 version of shmid64_ds and msqid64_ds · 1a512c08
      Arnd Bergmann 提交于
      A bugfix broke the x32 shmid64_ds and msqid64_ds data structure layout
      (as seen from user space)  a few years ago: Originally, __BITS_PER_LONG
      was defined as 64 on x32, so we did not have padding after the 64-bit
      __kernel_time_t fields, After __BITS_PER_LONG got changed to 32,
      applications would observe extra padding.
      
      In other parts of the uapi headers we seem to have a mix of those
      expecting either 32 or 64 on x32 applications, so we can't easily revert
      the path that broke these two structures.
      
      Instead, this patch decouples x32 from the other architectures and moves
      it back into arch specific headers, partially reverting the even older
      commit 73a2d096 ("x86: remove all now-duplicate header files").
      
      It's not clear whether this ever made any difference, since at least
      glibc carries its own (correct) copy of both of these header files,
      so possibly no application has ever observed the definitions here.
      
      Based on a suggestion from H.J. Lu, I tried out the tool from
      https://github.com/hjl-tools/linux-header to find other such
      bugs, which pointed out the same bug in statfs(), which also has
      a separate (correct) copy in glibc.
      
      Fixes: f4b4aae1 ("x86/headers/uapi: Fix __BITS_PER_LONG value for x32 builds")
      Signed-off-by: NArnd Bergmann <arnd@arndb.de>
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      Cc: "H . J . Lu" <hjl.tools@gmail.com>
      Cc: Jeffrey Walton <noloader@gmail.com>
      Cc: stable@vger.kernel.org
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Link: https://lkml.kernel.org/r/20180424212013.3967461-1-arnd@arndb.de
      1a512c08
    • P
      x86/setup: Do not reserve a crash kernel region if booted on Xen PV · 3db3eb28
      Petr Tesarik 提交于
      Xen PV domains cannot shut down and start a crash kernel. Instead,
      the crashing kernel makes a SCHEDOP_shutdown hypercall with the
      reason code SHUTDOWN_crash, cf. xen_crash_shutdown() machine op in
      arch/x86/xen/enlighten_pv.c.
      
      A crash kernel reservation is merely a waste of RAM in this case. It
      may also confuse users of kexec_load(2) and/or kexec_file_load(2).
      When flags include KEXEC_ON_CRASH or KEXEC_FILE_ON_CRASH,
      respectively, these syscalls return success, which is technically
      correct, but the crash kexec image will never be actually used.
      Signed-off-by: NPetr Tesarik <ptesarik@suse.com>
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      Reviewed-by: NJuergen Gross <jgross@suse.com>
      Cc: Tom Lendacky <thomas.lendacky@amd.com>
      Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
      Cc: Mikulas Patocka <mpatocka@redhat.com>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: xen-devel@lists.xenproject.org
      Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Jean Delvare <jdelvare@suse.de>
      Link: https://lkml.kernel.org/r/20180425120835.23cef60c@ezekiel.suse.cz
      3db3eb28
    • M
      arm64: avoid instrumenting atomic_ll_sc.o · 3789c122
      Mark Rutland 提交于
      Our out-of-line atomics are built with a special calling convention,
      preventing pointless stack spilling, and allowing us to patch call sites
      with ARMv8.1 atomic instructions.
      
      Instrumentation inserted by the compiler may result in calls to
      functions not following this special calling convention, resulting in
      registers being unexpectedly clobbered, and various problems resulting
      from this.
      
      For example, if a kernel is built with KCOV and ARM64_LSE_ATOMICS, the
      compiler inserts calls to __sanitizer_cov_trace_pc in the prologues of
      the atomic functions. This has been observed to result in spurious
      cmpxchg failures, leading to a hang early on in the boot process.
      
      This patch avoids such issues by preventing instrumentation of our
      out-of-line atomics.
      Signed-off-by: NMark Rutland <mark.rutland@arm.com>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Will Deacon <will.deacon@arm.com>
      Signed-off-by: NWill Deacon <will.deacon@arm.com>
      3789c122
    • L
      powerpc/kvm/booke: Fix altivec related build break · b2d7ecbe
      Laurentiu Tudor 提交于
      Add missing "altivec unavailable" interrupt injection helper
      thus fixing the linker error below:
      
        arch/powerpc/kvm/emulate_loadstore.o: In function `kvmppc_check_altivec_disabled':
        arch/powerpc/kvm/emulate_loadstore.c: undefined reference to `.kvmppc_core_queue_vec_unavail'
      
      Fixes: 09f98496 ("KVM: PPC: Book3S: Add MMIO emulation for VMX instructions")
      Signed-off-by: NLaurentiu Tudor <laurentiu.tudor@nxp.com>
      Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      b2d7ecbe
    • N
      powerpc: Fix deadlock with multiple calls to smp_send_stop · 6029755e
      Nicholas Piggin 提交于
      smp_send_stop can lock up the IPI path for any subsequent calls,
      because the receiving CPUs spin in their handler function. This
      started becoming a problem with the addition of an smp_send_stop
      call in the reboot path, because panics can reboot after doing
      their own smp_send_stop.
      
      The NMI IPI variant was fixed with ac61c115 ("powerpc: Fix
      smp_send_stop NMI IPI handling"), which leaves the smp_call_function
      variant.
      
      This is fixed by having smp_send_stop only ever do the
      smp_call_function once. This is a bit less robust than the NMI IPI
      fix, because any other call to smp_call_function after smp_send_stop
      could deadlock, but that has always been the case, and it was not
      been a problem before.
      
      Fixes: f2748bdf ("powerpc/powernv: Always stop secondaries before reboot/shutdown")
      Reported-by: NAbdul Haleem <abdhalee@linux.vnet.ibm.com>
      Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
      Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      6029755e
    • J
      x86/cpu/intel: Add missing TLB cpuid values · b837913f
      jacek.tomaka@poczta.fm 提交于
      Make kernel print the correct number of TLB entries on Intel Xeon Phi 7210
      (and others)
      
      Before:
      [ 0.320005] Last level dTLB entries: 4KB 0, 2MB 0, 4MB 0, 1GB 0
      After:
      [ 0.320005] Last level dTLB entries: 4KB 256, 2MB 128, 4MB 128, 1GB 16
      
      The entries do exist in the official Intel SMD but the type column there is
      incorrect (states "Cache" where it should read "TLB"), but the entries for
      the values 0x6B, 0x6C and 0x6D are correctly described as 'Data TLB'.
      Signed-off-by: NJacek Tomaka <jacek.tomaka@poczta.fm>
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      Link: https://lkml.kernel.org/r/20180423161425.24366-1-jacekt@dugeo.com
      b837913f
  11. 26 4月, 2018 10 次提交
  12. 25 4月, 2018 3 次提交
    • G
      bpf, x64: fix JIT emission for dead code · 1612a981
      Gianluca Borello 提交于
      Commit 2a5418a1 ("bpf: improve dead code sanitizing") replaced dead
      code with a series of ja-1 instructions, for safety. That made JIT
      compilation much more complex for some BPF programs. One instance of such
      programs is, for example:
      
      bool flag = false
      ...
      /* A bunch of other code */
      ...
      if (flag)
              do_something()
      
      In some cases llvm is not able to remove at compile time the code for
      do_something(), so the generated BPF program ends up with a large amount
      of dead instructions. In one specific real life example, there are two
      series of ~500 and ~1000 dead instructions in the program. When the
      verifier replaces them with a series of ja-1 instructions, it causes an
      interesting behavior at JIT time.
      
      During the first pass, since all the instructions are estimated at 64
      bytes, the ja-1 instructions end up being translated as 5 bytes JMP
      instructions (0xE9), since the jump offsets become increasingly large (>
      127) as each instruction gets discovered to be 5 bytes instead of the
      estimated 64.
      
      Starting from the second pass, the first N instructions of the ja-1
      sequence get translated into 2 bytes JMPs (0xEB) because the jump offsets
      become <= 127 this time. In particular, N is defined as roughly 127 / (5
      - 2) ~= 42. So, each further pass will make the subsequent N JMP
      instructions shrink from 5 to 2 bytes, making the image shrink every time.
      This means that in order to have the entire program converge, there need
      to be, in the real example above, at least ~1000 / 42 ~= 24 passes just
      for translating the dead code. If we add this number to the passes needed
      to translate the other non dead code, it brings such program to 40+
      passes, and JIT doesn't complete. Ultimately the userspace loader fails
      because such BPF program was supposed to be part of a prog array owner
      being JITed.
      
      While it is certainly possible to try to refactor such programs to help
      the compiler remove dead code, the behavior is not really intuitive and it
      puts further burden on the BPF developer who is not expecting such
      behavior. To make things worse, such programs are working just fine in all
      the kernel releases prior to the ja-1 fix.
      
      A possible approach to mitigate this behavior consists into noticing that
      for ja-1 instructions we don't really need to rely on the estimated size
      of the previous and current instructions, we know that a -1 BPF jump
      offset can be safely translated into a 0xEB instruction with a jump offset
      of -2.
      
      Such fix brings the BPF program in the previous example to complete again
      in ~9 passes.
      
      Fixes: 2a5418a1 ("bpf: improve dead code sanitizing")
      Signed-off-by: NGianluca Borello <g.borello@gmail.com>
      Acked-by: NAlexei Starovoitov <ast@kernel.org>
      Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      1612a981
    • S
      tracing/x86: Update syscall trace events to handle new prefixed syscall func names · 1c758a22
      Steven Rostedt (VMware) 提交于
      Arnaldo noticed that the latest kernel is missing the syscall event system
      directory in x86. I bisected it down to d5a00528 ("syscalls/core,
      syscalls/x86: Rename struct pt_regs-based sys_*() to __x64_sys_*()").
      
      The system call trace events are special, as there is only one trace event
      for all system calls (the raw_syscalls). But a macro that wraps the system
      calls creates meta data for them that copies the name to find the system
      call that maps to the system call table (the number). At boot up, it does a
      kallsyms lookup of the system call table to find the function that maps to
      the meta data of the system call. If it does not find a function, then that
      system call is ignored.
      
      Because the x86 system calls had "__x64_", or "__ia32_" prefixed to the
      "sys" for the names, they do not match the default compare algorithm. As
      this was a problem for power pc, the algorithm can be overwritten by the
      architecture. The solution is to have x86 have its own algorithm to do the
      compare and this brings back the system call trace events.
      
      Link: http://lkml.kernel.org/r/20180417174128.0f3457f0@gandalf.local.homeReported-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      Acked-by: NDominik Brodowski <linux@dominikbrodowski.net>
      Acked-by: NThomas Gleixner <tglx@linutronix.de>
      Fixes: d5a00528 ("syscalls/core, syscalls/x86: Rename struct pt_regs-based sys_*() to __x64_sys_*()")
      Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
      1c758a22
    • N
      powerpc: Fix smp_send_stop NMI IPI handling · ac61c115
      Nicholas Piggin 提交于
      The NMI IPI handler for a receiving CPU increments nmi_ipi_busy_count
      over the handler function call, which causes later smp_send_nmi_ipi()
      callers to spin until the call is finished.
      
      The stop_this_cpu() function never returns, so the busy count is never
      decremeted, which can cause the system to hang in some cases. For
      example panic() will call smp_send_stop() early on which calls
      stop_this_cpu() on other CPUs, then later in the reboot path,
      pnv_restart() will call smp_send_stop() again, which hangs.
      
      Fix this by adding a special case to the stop_this_cpu() handler to
      decrement the busy count, because it will never return.
      
      Now that the NMI/non-NMI versions of stop_this_cpu() are different,
      split them out into separate functions rather than doing #ifdef tricks
      to share the body between the two functions.
      
      Fixes: 6bed3237 ("powerpc: use NMI IPI for smp_send_stop")
      Reported-by: NAbdul Haleem <abdhalee@linux.vnet.ibm.com>
      Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
      [mpe: Split out the functions, tweak change log a bit]
      Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      ac61c115