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  1. 31 Jan, 2023 1 commit
    • Michael Ellerman's avatar
      powerpc/imc-pmu: Revert nest_init_lock to being a mutex · ad53db4a
      Michael Ellerman authored 
      The recent commit 76d588dd ("powerpc/imc-pmu: Fix use of mutex in
IRQs disabled section") fixed warnings (and possible deadlocks) in the
IMC PMU driver by converting the locking to use spinlocks.

It also converted the init-time nest_init_lock to a spinlock, even
though it's not used at runtime in IRQ disabled sections or while
holding other spinlocks.

This leads to warnings such as:

  BUG: sleeping function called from invalid context at include/linux/percpu-rwsem.h:49
  in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0
  preempt_count: 1, expected: 0
  CPU: 7 PID: 1 Comm: swapper/0 Not tainted 6.2.0-rc2-14719-gf12cd061-dirty #1
  Hardware name: Mambo,Simulated-System POWER9 0x4e1203 opal:v6.6.6 PowerNV
  Call Trace:
    dump_stack_lvl+0x74/0xa8 (unreliable)
    __might_resched+0x178/0x1a0
    __cpuhp_setup_state+0x64/0x1e0
    init_imc_pmu+0xe48/0x1250
    opal_imc_counters_probe+0x30c/0x6a0
    platform_probe+0x78/0x110
    really_probe+0x104/0x420
    __driver_probe_device+0xb0/0x170
    driver_probe_device+0x58/0x180
    __driver_attach+0xd8/0x250
    bus_for_each_dev+0xb4/0x140
    driver_attach+0x34/0x50
    bus_add_driver+0x1e8/0x2d0
    driver_register+0xb4/0x1c0
    __platform_driver_register+0x38/0x50
    opal_imc_driver_init+0x2c/0x40
    do_one_initcall+0x80/0x360
    kernel_init_freeable+0x310/0x3b8
    kernel_init+0x30/0x1a0
    ret_from_kernel_thread+0x5c/0x64

Fix it by converting nest_init_lock back to a mutex, so that we can call
sleeping functions while holding it. There is no interaction between
nest_init_lock and the runtime spinlocks used by the actual PMU routines.

Fixes: 76d588dd ("powerpc/imc-pmu: Fix use of mutex in IRQs disabled section")
Tested-by: Kajol Jain<kjain@linux.ibm.com>
Reviewed-by: Kajol Jain<kjain@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230130014401.540543-1-mpe@ellerman.id.au
      ad53db4a
  3. 30 Jan, 2023 4 commits
  5. 11 Jan, 2023 3 commits
    • Yang Yingliang's avatar
      powerpc/64s/hash: Make stress_hpt_timer_fn() static · f12cd061
      Yang Yingliang authored 
      stress_hpt_timer_fn() is only used in hash_utils.c, make it static.

Fixes: 6b34a099 ("powerpc/64s/hash: add stress_hpt kernel boot option to increase hash faults")
Signed-off-by: default avatarYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221228093603.3166599-1-yangyingliang@huawei.com
      f12cd061
    • Kajol Jain's avatar
      powerpc/imc-pmu: Fix use of mutex in IRQs disabled section · 76d588dd
      Kajol Jain authored 
      Current imc-pmu code triggers a WARNING with CONFIG_DEBUG_ATOMIC_SLEEP
and CONFIG_PROVE_LOCKING enabled, while running a thread_imc event.

Command to trigger the warning:
  # perf stat -e thread_imc/CPM_CS_FROM_L4_MEM_X_DPTEG/ sleep 5

   Performance counter stats for 'sleep 5':

                   0      thread_imc/CPM_CS_FROM_L4_MEM_X_DPTEG/

         5.002117947 seconds time elapsed

         0.000131000 seconds user
         0.001063000 seconds sys

Below is snippet of the warning in dmesg:

  BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580
  in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 2869, name: perf-exec
  preempt_count: 2, expected: 0
  4 locks held by perf-exec/2869:
   #0: c00000004325c540 (&sig->cred_guard_mutex){+.+.}-{3:3}, at: bprm_execve+0x64/0xa90
   #1: c00000004325c5d8 (&sig->exec_update_lock){++++}-{3:3}, at: begin_new_exec+0x460/0xef0
   #2: c0000003fa99d4e0 (&cpuctx_lock){-...}-{2:2}, at: perf_event_exec+0x290/0x510
   #3: c000000017ab8418 (&ctx->lock){....}-{2:2}, at: perf_event_exec+0x29c/0x510
  irq event stamp: 4806
  hardirqs last  enabled at (4805): [<c000000000f65b94>] _raw_spin_unlock_irqrestore+0x94/0xd0
  hardirqs last disabled at (4806): [<c0000000003fae44>] perf_event_exec+0x394/0x510
  softirqs last  enabled at (0): [<c00000000013c404>] copy_process+0xc34/0x1ff0
  softirqs last disabled at (0): [<0000000000000000>] 0x0
  CPU: 36 PID: 2869 Comm: perf-exec Not tainted 6.2.0-rc2-00011-g1247637727f2 #61
  Hardware name: 8375-42A POWER9 0x4e1202 opal:v7.0-16-g9b85f7d961 PowerNV
  Call Trace:
    dump_stack_lvl+0x98/0xe0 (unreliable)
    __might_resched+0x2f8/0x310
    __mutex_lock+0x6c/0x13f0
    thread_imc_event_add+0xf4/0x1b0
    event_sched_in+0xe0/0x210
    merge_sched_in+0x1f0/0x600
    visit_groups_merge.isra.92.constprop.166+0x2bc/0x6c0
    ctx_flexible_sched_in+0xcc/0x140
    ctx_sched_in+0x20c/0x2a0
    ctx_resched+0x104/0x1c0
    perf_event_exec+0x340/0x510
    begin_new_exec+0x730/0xef0
    load_elf_binary+0x3f8/0x1e10
  ...
  do not call blocking ops when !TASK_RUNNING; state=2001 set at [<00000000fd63e7cf>] do_nanosleep+0x60/0x1a0
  WARNING: CPU: 36 PID: 2869 at kernel/sched/core.c:9912 __might_sleep+0x9c/0xb0
  CPU: 36 PID: 2869 Comm: sleep Tainted: G        W          6.2.0-rc2-00011-g1247637727f2 #61
  Hardware name: 8375-42A POWER9 0x4e1202 opal:v7.0-16-g9b85f7d961 PowerNV
  NIP:  c000000000194a1c LR: c000000000194a18 CTR: c000000000a78670
  REGS: c00000004d2134e0 TRAP: 0700   Tainted: G        W           (6.2.0-rc2-00011-g1247637727f2)
  MSR:  9000000000021033 <SF,HV,ME,IR,DR,RI,LE>  CR: 48002824  XER: 00000000
  CFAR: c00000000013fb64 IRQMASK: 1

The above warning triggered because the current imc-pmu code uses mutex
lock in interrupt disabled sections. The function mutex_lock()
internally calls __might_resched(), which will check if IRQs are
disabled and in case IRQs are disabled, it will trigger the warning.

Fix the issue by changing the mutex lock to spinlock.

Fixes: 8f95faaa ("powerpc/powernv: Detect and create IMC device")
Reported-by: default avatarMichael Petlan <mpetlan@redhat.com>
Reported-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarKajol Jain <kjain@linux.ibm.com>
[mpe: Fix comments, trim oops in change log, add reported-by tags]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230106065157.182648-1-kjain@linux.ibm.com
      76d588dd
    • Ojaswin Mujoo's avatar
      powerpc/boot: Fix incorrect version calculation issue in ld_version · 3287ebd7
      Ojaswin Mujoo authored 
      The ld_version() function computes the wrong version value for certain
ld versions such as the following:

  $ ld --version
  GNU ld (GNU Binutils; SUSE Linux Enterprise 15)
  2.37.20211103-150100.7.37

For input 2.37.20211103, the value computed is 202348030000 which is
higher than the value for a later version like 2.39.0, which is
23900000.

This issue was highlighted because with the above ld version, the
powerpc kernel build started failing with ld error: "unrecognized option
--no-warn-rwx-segments". This was caused due to the recent commit
579aee9f ("powerpc: suppress some linker warnings in recent linker
versions") which added the --no-warn-rwx-segments linker flag if the ld
version is greater than 2.39.

Due to the bug in ld_version(), ld version 2.37.20111103 is wrongly
calculated to be greater than 2.39 and the unsupported flag is added.

To fix it, if version is of the form x.y.z and length(z) == 8, then most
probably it is a date [yyyymmdd] commonly used for release snapshots and
not an actual new version. Hence, ignore the date part replacing it with
0.

Fixes: 579aee9f ("powerpc: suppress some linker warnings in recent linker versions")
Signed-off-by: default avatarOjaswin Mujoo <ojaswin@linux.ibm.com>
[mpe: Tweak change log wording/formatting, add Fixes tag]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230104202437.90039-1-ojaswin@linux.ibm.com
      3287ebd7
  7. 05 Jan, 2023 3 commits
    • Michael Ellerman's avatar
      powerpc/vmlinux.lds: Don't discard .comment · be5f95c8
      Michael Ellerman authored 
      Although the powerpc linker script mentions .comment in the DISCARD
section, that has never actually caused it to be discarded, because the
earlier ELF_DETAILS macro (previously STABS_DEBUG) explicitly includes
.comment.

However commit 99cb0d91 ("arch: fix broken BuildID for arm64 and
riscv") introduced an earlier use of DISCARD as part of the RO_DATA
macro. With binutils < 2.36 that causes the DISCARD directives later in
the script to be applied earlier, causing .comment to actually be
discarded.

It's confusing to explicitly include and discard .comment, and even more
so if the behaviour depends on the toolchain version. So don't discard
.comment in order to maintain the existing behaviour in all cases.

Fixes: 83a092cf ("powerpc: Link warning for orphan sections")
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230105132349.384666-3-mpe@ellerman.id.au
      be5f95c8
    • Michael Ellerman's avatar
      powerpc/vmlinux.lds: Don't discard .rela* for relocatable builds · 07b050f9
      Michael Ellerman authored 
      Relocatable kernels must not discard relocations, they need to be
processed at runtime. As such they are included for CONFIG_RELOCATABLE
builds in the powerpc linker script (line 340).

However they are also unconditionally discarded later in the
script (line 414). Previously that worked because the earlier inclusion
superseded the discard.

However commit 99cb0d91 ("arch: fix broken BuildID for arm64 and
riscv") introduced an earlier use of DISCARD as part of the RO_DATA
macro (line 137). With binutils < 2.36 that causes the DISCARD
directives later in the script to be applied earlier, causing .rela* to
actually be discarded at link time, leading to build warnings and a
kernel that doesn't boot:

  ld: warning: discarding dynamic section .rela.init.rodata

Fix it by conditionally discarding .rela* only when CONFIG_RELOCATABLE
is disabled.

Fixes: 99cb0d91 ("arch: fix broken BuildID for arm64 and riscv")
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>

Link: https://lore.kernel.org/r/20230105132349.384666-2-mpe@ellerman.id.au
      07b050f9
    • Michael Ellerman's avatar
      powerpc/vmlinux.lds: Define RUNTIME_DISCARD_EXIT · 4b9880db
      Michael Ellerman authored 
      The powerpc linker script explicitly includes .exit.text, because
otherwise the link fails due to references from __bug_table and
__ex_table. The code is freed (discarded) at runtime along with
.init.text and data.

That has worked in the past despite powerpc not defining
RUNTIME_DISCARD_EXIT because DISCARDS appears late in the powerpc linker
script (line 410), and the explicit inclusion of .exit.text
earlier (line 280) supersedes the discard.

However commit 99cb0d91 ("arch: fix broken BuildID for arm64 and
riscv") introduced an earlier use of DISCARD as part of the RO_DATA
macro (line 136). With binutils < 2.36 that causes the DISCARD
directives later in the script to be applied earlier [1], causing
.exit.text to actually be discarded at link time, leading to build
errors:

  '.exit.text' referenced in section '__bug_table' of crypto/algboss.o: defined in
  discarded section '.exit.text' of crypto/algboss.o
  '.exit.text' referenced in section '__ex_table' of drivers/nvdimm/core.o: defined in
  discarded section '.exit.text' of drivers/nvdimm/core.o

Fix it by defining RUNTIME_DISCARD_EXIT, which causes the generic
DISCARDS macro to not include .exit.text at all.

1: https://lore.kernel.org/lkml/87fscp2v7k.fsf@igel.home/

Fixes: 99cb0d91 ("arch: fix broken BuildID for arm64 and riscv")
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230105132349.384666-1-mpe@ellerman.id.au
      4b9880db
  9. 01 Jan, 2023 6 commits
  11. 31 Dec, 2022 2 commits
  13. 30 Dec, 2022 19 commits
  15. 29 Dec, 2022 2 commits
    • Linus Torvalds's avatar
      Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm · 2258c2dc
      Linus Torvalds authored 
      Pull kvm fixes from Paolo Bonzini:
 "Changes that were posted too late for 6.1, or after the release.

  x86:

   - several fixes to nested VMX execution controls

   - fixes and clarification to the documentation for Xen emulation

   - do not unnecessarily release a pmu event with zero period

   - MMU fixes

   - fix Coverity warning in kvm_hv_flush_tlb()

  selftests:

   - fixes for the ucall mechanism in selftests

   - other fixes mostly related to compilation with clang"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (41 commits)
  KVM: selftests: restore special vmmcall code layout needed by the harness
  Documentation: kvm: clarify SRCU locking order
  KVM: x86: fix deadlock for KVM_XEN_EVTCHN_RESET
  KVM: x86/xen: Documentation updates and clarifications
  KVM: x86/xen: Add KVM_XEN_INVALID_GPA and KVM_XEN_INVALID_GFN to uapi
  KVM: x86/xen: Simplify eventfd IOCTLs
  KVM: x86/xen: Fix SRCU/RCU usage in readers of evtchn_ports
  KVM: x86/xen: Use kvm_read_guest_virt() instead of open-coding it badly
  KVM: x86/xen: Fix memory leak in kvm_xen_write_hypercall_page()
  KVM: Delete extra block of "};" in the KVM API documentation
  kvm: x86/mmu: Remove duplicated "be split" in spte.h
  kvm: Remove the unused macro KVM_MMU_READ_{,UN}LOCK()
  MAINTAINERS: adjust entry after renaming the vmx hyperv files
  KVM: selftests: Mark correct page as mapped in virt_map()
  KVM: arm64: selftests: Don't identity map the ucall MMIO hole
  KVM: selftests: document the default implementation of vm_vaddr_populate_bitmap
  KVM: selftests: Use magic value to signal ucall_alloc() failure
  KVM: selftests: Disable "gnu-variable-sized-type-not-at-end" warning
  KVM: selftests: Include lib.mk before consuming $(CC)
  KVM: selftests: Explicitly disable builtins for mem*() overrides
  ...
      2258c2dc
    • Jens Axboe's avatar
      Merge tag 'nvme-6.2-2022-12-29' of git://git.infradead.org/nvme into block-6.2 · 1551ed5a
      Jens Axboe authored 
      Pull NVMe fixes from Christoph:

"nvme fixes for Linux 6.2

 - fix various problems in handling the Command Supported and Effects log
   (Christoph Hellwig)
 - don't allow unprivileged passthrough of commands that don't transfer
   data but modify logical block content (Christoph Hellwig)
 - add a features and quirks policy document (Christoph Hellwig)
 - fix some really nasty code that was correct but made smatch complain
   (Sagi Grimberg)"

* tag 'nvme-6.2-2022-12-29' of git://git.infradead.org/nvme:
  nvme-auth: fix smatch warning complaints
  nvme: consult the CSE log page for unprivileged passthrough
  nvme: also return I/O command effects from nvme_command_effects
  nvmet: don't defer passthrough commands with trivial effects to the workqueue
  nvmet: set the LBCC bit for commands that modify data
  nvmet: use NVME_CMD_EFFECTS_CSUPP instead of open coding it
  nvme: fix the NVME_CMD_EFFECTS_CSE_MASK definition
  docs, nvme: add a feature and quirk policy document
      1551ed5a
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