linux.git/arch/s390/include, branch v5.14

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2021-07-29T16:42:09+00:00

Pull kvm fixes from Paolo Bonzini:
 "ARM:

   - Fix MTE shared page detection

   - Enable selftest's use of PMU registers when asked to

  s390:

   - restore 5.13 debugfs names

  x86:

   - fix sizes for vcpu-id indexed arrays

   - fixes for AMD virtualized LAPIC (AVIC)

   - other small bugfixes

  Generic:

   - access tracking performance test

   - dirty_log_perf_test command line parsing fix

   - Fix selftest use of obsolete pthread_yield() in favour of
     sched_yield()

   - use cpu_relax when halt polling

   - fixed missing KVM_CLEAR_DIRTY_LOG compat ioctl"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: add missing compat KVM_CLEAR_DIRTY_LOG
  KVM: use cpu_relax when halt polling
  KVM: SVM: use vmcb01 in svm_refresh_apicv_exec_ctrl
  KVM: SVM: tweak warning about enabled AVIC on nested entry
  KVM: SVM: svm_set_vintr don't warn if AVIC is active but is about to be deactivated
  KVM: s390: restore old debugfs names
  KVM: SVM: delay svm_vcpu_init_msrpm after svm->vmcb is initialized
  KVM: selftests: Introduce access_tracking_perf_test
  KVM: selftests: Fix missing break in dirty_log_perf_test arg parsing
  x86/kvm: fix vcpu-id indexed array sizes
  KVM: x86: Check the right feature bit for MSR_KVM_ASYNC_PF_ACK access
  docs: virt: kvm: api.rst: replace some characters
  KVM: Documentation: Fix KVM_CAP_ENFORCE_PV_FEATURE_CPUID name
  KVM: nSVM: Swap the parameter order for svm_copy_vmrun_state()/svm_copy_vmloadsave_state()
  KVM: nSVM: Rename nested_svm_vmloadsave() to svm_copy_vmloadsave_state()
  KVM: arm64: selftests: get-reg-list: actually enable pmu regs in pmu sublist
  KVM: selftests: change pthread_yield to sched_yield
  KVM: arm64: Fix detection of shared VMAs on guest fault

KVM: s390: restore old debugfs names

2021-07-27T20:59:00+00:00

commit bc9e9e672df9 ("KVM: debugfs: Reuse binary stats descriptors")
did replace the old definitions with the binary ones. While doing that
it missed that some files are names different than the counters. This
is especially important for kvm_stat which does have special handling
for counters named instruction_*.

Fixes: commit bc9e9e672df9 ("KVM: debugfs: Reuse binary stats descriptors")
CC: Jing Zhang 
Signed-off-by: Christian Borntraeger 
Message-Id: <20210726150108.5603-1-borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini

s390/ftrace: fix ftrace_update_ftrace_func implementation

2021-07-15T10:54:58+00:00

s390 enforces DYNAMIC_FTRACE if FUNCTION_TRACER is selected.
At the same time implementation of ftrace_caller is not compliant with
HAVE_DYNAMIC_FTRACE since it doesn't provide implementation of
ftrace_update_ftrace_func() and calls ftrace_trace_function() directly.

The subtle difference is that during ftrace code patching ftrace
replaces function tracer via ftrace_update_ftrace_func() and activates
it back afterwards. Unexpected direct calls to ftrace_trace_function()
during ftrace code patching leads to nullptr-dereferences when tracing
is activated for one of functions which are used during code patching.
Those function currently are:
copy_from_kernel_nofault()
copy_from_kernel_nofault_allowed()
preempt_count_sub() [with debug_defconfig]
preempt_count_add() [with debug_defconfig]

Corresponding KASAN report:
 BUG: KASAN: nullptr-dereference in function_trace_call+0x316/0x3b0
 Read of size 4 at addr 0000000000001e08 by task migration/0/15

 CPU: 0 PID: 15 Comm: migration/0 Tainted: G B 5.13.0-41423-g08316af3644d
 Hardware name: IBM 3906 M04 704 (LPAR)
 Stopper: multi_cpu_stop+0x0/0x3e0 <- stop_machine_cpuslocked+0x1e4/0x218
 Call Trace:
  [<0000000001f77caa>] show_stack+0x16a/0x1d0
  [<0000000001f8de42>] dump_stack+0x15a/0x1b0
  [<0000000001f81d56>] print_address_description.constprop.0+0x66/0x2e0
  [<000000000082b0ca>] kasan_report+0x152/0x1c0
  [<00000000004cfd8e>] function_trace_call+0x316/0x3b0
  [<0000000001fb7082>] ftrace_caller+0x7a/0x7e
  [<00000000006bb3e6>] copy_from_kernel_nofault_allowed+0x6/0x10
  [<00000000006bb42e>] copy_from_kernel_nofault+0x3e/0xd0
  [<000000000014605c>] ftrace_make_call+0xb4/0x1f8
  [<000000000047a1b4>] ftrace_replace_code+0x134/0x1d8
  [<000000000047a6e0>] ftrace_modify_all_code+0x120/0x1d0
  [<000000000047a7ec>] __ftrace_modify_code+0x5c/0x78
  [<000000000042395c>] multi_cpu_stop+0x224/0x3e0
  [<0000000000423212>] cpu_stopper_thread+0x33a/0x5a0
  [<0000000000243ff2>] smpboot_thread_fn+0x302/0x708
  [<00000000002329ea>] kthread+0x342/0x408
  [<00000000001066b2>] __ret_from_fork+0x92/0xf0
  [<0000000001fb57fa>] ret_from_fork+0xa/0x30

 The buggy address belongs to the page:
 page:(____ptrval____) refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1
 flags: 0x1ffff00000001000(reserved|node=0|zone=0|lastcpupid=0x1ffff)
 raw: 1ffff00000001000 0000040000000048 0000040000000048 0000000000000000
 raw: 0000000000000000 0000000000000000 ffffffff00000001 0000000000000000
 page dumped because: kasan: bad access detected

 Memory state around the buggy address:
  0000000000001d00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0000000000001d80: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
 >0000000000001e00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
                       ^
  0000000000001e80: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0000000000001f00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
 ==================================================================

To fix that introduce ftrace_func callback to be called from
ftrace_caller and update it in ftrace_update_ftrace_func().

Fixes: 4cc9bed034d1 ("[S390] cleanup ftrace backend functions")
Cc: stable@vger.kernel.org
Reviewed-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Heiko Carstens

s390: preempt: Fix preempt_count initialization

2021-07-08T20:12:18+00:00

S390's init_idle_preempt_count(p, cpu) doesn't actually let us initialize the
preempt_count of the requested CPU's idle task: it unconditionally writes
to the current CPU's. This clearly conflicts with idle_threads_init(),
which intends to initialize *all* the idle tasks, including their
preempt_count (or their CPU's, if the arch uses a per-CPU preempt_count).

Unfortunately, it seems the way s390 does things doesn't let us initialize
every possible CPU's preempt_count early on, as the pages where this
resides are only allocated when a CPU is brought up and are freed when it
is brought down.

Let the arch-specific code set a CPU's preempt_count when its lowcore is
allocated, and turn init_idle_preempt_count() into an empty stub.

Fixes: f1a0a376ca0c ("sched/core: Initialize the idle task with preemption disabled")
Reported-by: Guenter Roeck 
Signed-off-by: Valentin Schneider 
Tested-by: Guenter Roeck 
Reviewed-by: Heiko Carstens 
Link: https://lore.kernel.org/r/20210707163338.1623014-1-valentin.schneider@arm.com
Signed-off-by: Vasily Gorbik

s390/linkage: increase asm symbols alignment to 16

2021-07-08T20:12:18+00:00

Both clang and gcc (for -march=z13 and later) align functions to 16
bytes at -O2 to benefit branch prediction.

Make asm symbols alignment consistent with that.

This also benefits potential ftrace code patching, which is currently
able to patch 8 aligned bytes at once.

With defconfig this currently increases .text size by 4104 bytes.

Reviewed-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390: rename CALL_ON_STACK_NORETURN() to call_on_stack_noreturn()

2021-07-08T20:12:18+00:00

Lower case matches the call_on_stack() macro and is easier to read.

Reviewed-by: Sven Schnelle 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390: add type checking to CALL_ON_STACK_NORETURN() macro

2021-07-08T20:12:18+00:00

Make sure the to be called function takes no arguments (and returns void).
Otherwise usage of CALL_ON_STACK_NORETURN() would generate broken code.

Reviewed-by: Sven Schnelle 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390: remove old CALL_ON_STACK() macro

2021-07-08T20:12:18+00:00

Reviewed-by: Sven Schnelle 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/softirq: use call_on_stack() macro

2021-07-08T20:12:18+00:00

Reviewed-by: Sven Schnelle 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390: introduce proper type handling call_on_stack() macro

2021-07-08T20:12:17+00:00

The existing CALL_ON_STACK() macro allows for subtle bugs:

- There is no type checking of the function that is being called. That
  is: missing or too many arguments do not cause any compile error or
  warning. The same is true if the return type of the called function
  changes. This can lead to quite random bugs.

- Sign and zero extension of arguments is missing. Given that the s390
  C ABI requires that the caller of a function performs proper sign
  and zero extension this can also lead to subtle bugs.

- If arguments to the CALL_ON_STACK() macros contain functions calls
  register corruption can happen due to register asm constructs being
  used.

Therefore introduce a new call_on_stack() macro which is supposed to
fix all these problems.

Reviewed-by: Sven Schnelle 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik