1
Commit Graph

408 Commits

Author SHA1 Message Date
Kirill A. Shutemov
26ba7353ca x86/smp: Add smp_ops.stop_this_cpu() callback
If the helper is defined, it is called instead of halt() to stop the CPU at the
end of stop_this_cpu() and on crash CPU shutdown.

ACPI MADT will use it to hand over the CPU to BIOS in order to be able to wake
it up again after kexec.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Kai Huang <kai.huang@intel.com>
Tested-by: Tao Liu <ltao@redhat.com>
Link: https://lore.kernel.org/r/20240614095904.1345461-17-kirill.shutemov@linux.intel.com
2024-06-17 17:46:20 +02:00
Linus Torvalds
685d982112 Core x86 changes for v6.9:
- The biggest change is the rework of the percpu code,
   to support the 'Named Address Spaces' GCC feature,
   by Uros Bizjak:
 
    - This allows C code to access GS and FS segment relative
      memory via variables declared with such attributes,
      which allows the compiler to better optimize those accesses
      than the previous inline assembly code.
 
    - The series also includes a number of micro-optimizations
      for various percpu access methods, plus a number of
      cleanups of %gs accesses in assembly code.
 
    - These changes have been exposed to linux-next testing for
      the last ~5 months, with no known regressions in this area.
 
 - Fix/clean up __switch_to()'s broken but accidentally
   working handling of FPU switching - which also generates
   better code.
 
 - Propagate more RIP-relative addressing in assembly code,
   to generate slightly better code.
 
 - Rework the CPU mitigations Kconfig space to be less idiosyncratic,
   to make it easier for distros to follow & maintain these options.
 
 - Rework the x86 idle code to cure RCU violations and
   to clean up the logic.
 
 - Clean up the vDSO Makefile logic.
 
 - Misc cleanups and fixes.
 
 [ Please note that there's a higher number of merge commits in
   this branch (three) than is usual in x86 topic trees. This happened
   due to the long testing lifecycle of the percpu changes that
   involved 3 merge windows, which generated a longer history
   and various interactions with other core x86 changes that we
   felt better about to carry in a single branch. ]
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-core-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core x86 updates from Ingo Molnar:

 - The biggest change is the rework of the percpu code, to support the
   'Named Address Spaces' GCC feature, by Uros Bizjak:

      - This allows C code to access GS and FS segment relative memory
        via variables declared with such attributes, which allows the
        compiler to better optimize those accesses than the previous
        inline assembly code.

      - The series also includes a number of micro-optimizations for
        various percpu access methods, plus a number of cleanups of %gs
        accesses in assembly code.

      - These changes have been exposed to linux-next testing for the
        last ~5 months, with no known regressions in this area.

 - Fix/clean up __switch_to()'s broken but accidentally working handling
   of FPU switching - which also generates better code

 - Propagate more RIP-relative addressing in assembly code, to generate
   slightly better code

 - Rework the CPU mitigations Kconfig space to be less idiosyncratic, to
   make it easier for distros to follow & maintain these options

 - Rework the x86 idle code to cure RCU violations and to clean up the
   logic

 - Clean up the vDSO Makefile logic

 - Misc cleanups and fixes

* tag 'x86-core-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits)
  x86/idle: Select idle routine only once
  x86/idle: Let prefer_mwait_c1_over_halt() return bool
  x86/idle: Cleanup idle_setup()
  x86/idle: Clean up idle selection
  x86/idle: Sanitize X86_BUG_AMD_E400 handling
  sched/idle: Conditionally handle tick broadcast in default_idle_call()
  x86: Increase brk randomness entropy for 64-bit systems
  x86/vdso: Move vDSO to mmap region
  x86/vdso/kbuild: Group non-standard build attributes and primary object file rules together
  x86/vdso: Fix rethunk patching for vdso-image-{32,64}.o
  x86/retpoline: Ensure default return thunk isn't used at runtime
  x86/vdso: Use CONFIG_COMPAT_32 to specify vdso32
  x86/vdso: Use $(addprefix ) instead of $(foreach )
  x86/vdso: Simplify obj-y addition
  x86/vdso: Consolidate targets and clean-files
  x86/bugs: Rename CONFIG_RETHUNK              => CONFIG_MITIGATION_RETHUNK
  x86/bugs: Rename CONFIG_CPU_SRSO             => CONFIG_MITIGATION_SRSO
  x86/bugs: Rename CONFIG_CPU_IBRS_ENTRY       => CONFIG_MITIGATION_IBRS_ENTRY
  x86/bugs: Rename CONFIG_CPU_UNRET_ENTRY      => CONFIG_MITIGATION_UNRET_ENTRY
  x86/bugs: Rename CONFIG_SLS                  => CONFIG_MITIGATION_SLS
  ...
2024-03-11 19:53:15 -07:00
Thomas Gleixner
35ce64922c x86/idle: Select idle routine only once
The idle routine selection is done on every CPU bringup operation and
has a guard in place which is effective after the first invocation,
which is a pointless exercise.

Invoke it once on the boot CPU and mark the related functions __init.
The guard check has to stay as xen_set_default_idle() runs early.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/87edcu6vaq.ffs@tglx
2024-03-04 17:39:24 +01:00
Thomas Gleixner
5f75916ec6 x86/idle: Let prefer_mwait_c1_over_halt() return bool
The return value is truly boolean. Make it so.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240229142248.518723854@linutronix.de
2024-03-04 17:39:24 +01:00
Thomas Gleixner
f3d7eab7be x86/idle: Cleanup idle_setup()
Updating the static call for x86_idle() from idle_setup() is
counter-intuitive.

Let select_idle_routine() handle it like the other idle choices, which
allows to simplify the idle selection later on.

While at it rewrite comments and return a proper error code and not -1.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240229142248.455616019@linutronix.de
2024-03-04 17:39:24 +01:00
Thomas Gleixner
0ab562875c x86/idle: Clean up idle selection
Clean up the code to make it readable. No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240229142248.392017685@linutronix.de
2024-03-04 17:39:24 +01:00
Thomas Gleixner
cb81deefb5 x86/idle: Sanitize X86_BUG_AMD_E400 handling
amd_e400_idle(), the idle routine for AMD CPUs which are affected by
erratum 400 violates the RCU constraints by invoking tick_broadcast_enter()
and tick_broadcast_exit() after the core code has marked RCU non-idle.  The
functions can end up in lockdep or tracing, which rightfully triggers a
RCU warning.

The core code provides now a static branch conditional invocation of the
broadcast functions.

Remove amd_e400_idle(), enforce default_idle() and enable the static branch
on affected CPUs to cure this.

  [ bp: Fold in a fix for a IS_ENABLED() check fail missing a "CONFIG_"
    prefix which tglx spotted. ]

Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/877cim6sis.ffs@tglx
2024-03-04 17:38:06 +01:00
Kees Cook
44c76825d6 x86: Increase brk randomness entropy for 64-bit systems
In commit c1d171a002 ("x86: randomize brk"), arch_randomize_brk() was
defined to use a 32MB range (13 bits of entropy), but was never increased
when moving to 64-bit. The default arch_randomize_brk() uses 32MB for
32-bit tasks, and 1GB (18 bits of entropy) for 64-bit tasks.

Update x86_64 to match the entropy used by arm64 and other 64-bit
architectures.

Reported-by: y0un9n132@gmail.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Jiri Kosina <jkosina@suse.com>
Closes: https://lore.kernel.org/linux-hardening/CA+2EKTVLvc8hDZc+2Yhwmus=dzOUG5E4gV7ayCbu0MPJTZzWkw@mail.gmail.com/
Link: https://lore.kernel.org/r/20240217062545.1631668-1-keescook@chromium.org
2024-02-27 00:23:55 +01:00
Thomas Gleixner
8078f4d610 x86/cpu/topology: Rename smp_num_siblings
It's really a non-intuitive name. Rename it to __max_threads_per_core which
is obvious.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20240213210253.011307973@linutronix.de
2024-02-15 22:07:45 +01:00
Bjorn Helgaas
54aa699e80 arch/x86: Fix typos
Fix typos, most reported by "codespell arch/x86".  Only touches comments,
no code changes.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20240103004011.1758650-1-helgaas@kernel.org
2024-01-03 11:46:22 +01:00
Rick Edgecombe
748c90c693 x86/shstk: Remove useless clone error handling
When clone fails after the shadow stack is allocated, any allocated shadow
stack is cleaned up in exit_thread() in copy_process(). So the logic in
copy_thread() is unneeded, and also will not handle failures that happen
outside of copy_thread().

In addition, since there is a second attempt to unmap the same shadow
stack, there is a race where an newly mapped region could get unmapped.

So remove the logic in copy_thread() and rely on exit_thread() to handle
clone failure.

Fixes: b2926a36b9 ("x86/shstk: Handle thread shadow stack")
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: H.J. Lu <hjl.tools@gmail.com>
Link: https://lore.kernel.org/all/20230908203655.543765-3-rick.p.edgecombe%40intel.com
2023-09-19 09:18:34 -07:00
Linus Torvalds
df57721f9a Add x86 shadow stack support
Convert IBT selftest to asm to fix objtool warning
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Merge tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 shadow stack support from Dave Hansen:
 "This is the long awaited x86 shadow stack support, part of Intel's
  Control-flow Enforcement Technology (CET).

  CET consists of two related security features: shadow stacks and
  indirect branch tracking. This series implements just the shadow stack
  part of this feature, and just for userspace.

  The main use case for shadow stack is providing protection against
  return oriented programming attacks. It works by maintaining a
  secondary (shadow) stack using a special memory type that has
  protections against modification. When executing a CALL instruction,
  the processor pushes the return address to both the normal stack and
  to the special permission shadow stack. Upon RET, the processor pops
  the shadow stack copy and compares it to the normal stack copy.

  For more information, refer to the links below for the earlier
  versions of this patch set"

Link: https://lore.kernel.org/lkml/20220130211838.8382-1-rick.p.edgecombe@intel.com/
Link: https://lore.kernel.org/lkml/20230613001108.3040476-1-rick.p.edgecombe@intel.com/

* tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits)
  x86/shstk: Change order of __user in type
  x86/ibt: Convert IBT selftest to asm
  x86/shstk: Don't retry vm_munmap() on -EINTR
  x86/kbuild: Fix Documentation/ reference
  x86/shstk: Move arch detail comment out of core mm
  x86/shstk: Add ARCH_SHSTK_STATUS
  x86/shstk: Add ARCH_SHSTK_UNLOCK
  x86: Add PTRACE interface for shadow stack
  selftests/x86: Add shadow stack test
  x86/cpufeatures: Enable CET CR4 bit for shadow stack
  x86/shstk: Wire in shadow stack interface
  x86: Expose thread features in /proc/$PID/status
  x86/shstk: Support WRSS for userspace
  x86/shstk: Introduce map_shadow_stack syscall
  x86/shstk: Check that signal frame is shadow stack mem
  x86/shstk: Check that SSP is aligned on sigreturn
  x86/shstk: Handle signals for shadow stack
  x86/shstk: Introduce routines modifying shstk
  x86/shstk: Handle thread shadow stack
  x86/shstk: Add user-mode shadow stack support
  ...
2023-08-31 12:20:12 -07:00
Rick Edgecombe
b2926a36b9 x86/shstk: Handle thread shadow stack
When a process is duplicated, but the child shares the address space with
the parent, there is potential for the threads sharing a single stack to
cause conflicts for each other. In the normal non-CET case this is handled
in two ways.

With regular CLONE_VM a new stack is provided by userspace such that the
parent and child have different stacks.

For vfork, the parent is suspended until the child exits. So as long as
the child doesn't return from the vfork()/CLONE_VFORK calling function and
sticks to a limited set of operations, the parent and child can share the
same stack.

For shadow stack, these scenarios present similar sharing problems. For the
CLONE_VM case, the child and the parent must have separate shadow stacks.
Instead of changing clone to take a shadow stack, have the kernel just
allocate one and switch to it.

Use stack_size passed from clone3() syscall for thread shadow stack size. A
compat-mode thread shadow stack size is further reduced to 1/4. This
allows more threads to run in a 32-bit address space. The clone() does not
pass stack_size, which was added to clone3(). In that case, use
RLIMIT_STACK size and cap to 4 GB.

For shadow stack enabled vfork(), the parent and child can share the same
shadow stack, like they can share a normal stack. Since the parent is
suspended until the child terminates, the child will not interfere with
the parent while executing as long as it doesn't return from the vfork()
and overwrite up the shadow stack. The child can safely overwrite down
the shadow stack, as the parent can just overwrite this later. So CET does
not add any additional limitations for vfork().

Free the shadow stack on thread exit by doing it in mm_release(). Skip
this when exiting a vfork() child since the stack is shared in the
parent.

During this operation, the shadow stack pointer of the new thread needs
to be updated to point to the newly allocated shadow stack. Since the
ability to do this is confined to the FPU subsystem, change
fpu_clone() to take the new shadow stack pointer, and update it
internally inside the FPU subsystem. This part was suggested by Thomas
Gleixner.

Co-developed-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Tested-by: Pengfei Xu <pengfei.xu@intel.com>
Tested-by: John Allen <john.allen@amd.com>
Tested-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/all/20230613001108.3040476-30-rick.p.edgecombe%40intel.com
2023-08-02 15:01:50 -07:00
Brian Gerst
3aec4ecb3d x86: Rewrite ret_from_fork() in C
When kCFI is enabled, special handling is needed for the indirect call
to the kernel thread function.  Rewrite the ret_from_fork() function in
C so that the compiler can properly handle the indirect call.

Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lkml.kernel.org/r/20230623225529.34590-3-brgerst@gmail.com
2023-07-10 09:52:25 +02:00
Tony Battersby
9b040453d4 x86/smp: Dont access non-existing CPUID leaf
stop_this_cpu() tests CPUID leaf 0x8000001f::EAX unconditionally. Intel
CPUs return the content of the highest supported leaf when a non-existing
leaf is read, while AMD CPUs return all zeros for unsupported leafs.

So the result of the test on Intel CPUs is lottery.

While harmless it's incorrect and causes the conditional wbinvd() to be
issued where not required.

Check whether the leaf is supported before reading it.

[ tglx: Adjusted changelog ]

Fixes: 08f253ec37 ("x86/cpu: Clear SME feature flag when not in use")
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/3817d810-e0f1-8ef8-0bbd-663b919ca49b@cybernetics.com
Link: https://lore.kernel.org/r/20230615193330.322186388@linutronix.de
2023-06-20 14:51:46 +02:00
Thomas Gleixner
1f5e7eb786 x86/smp: Make stop_other_cpus() more robust
Tony reported intermittent lockups on poweroff. His analysis identified the
wbinvd() in stop_this_cpu() as the culprit. This was added to ensure that
on SME enabled machines a kexec() does not leave any stale data in the
caches when switching from encrypted to non-encrypted mode or vice versa.

That wbinvd() is conditional on the SME feature bit which is read directly
from CPUID. But that readout does not check whether the CPUID leaf is
available or not. If it's not available the CPU will return the value of
the highest supported leaf instead. Depending on the content the "SME" bit
might be set or not.

That's incorrect but harmless. Making the CPUID readout conditional makes
the observed hangs go away, but it does not fix the underlying problem:

CPU0					CPU1

 stop_other_cpus()
   send_IPIs(REBOOT);			stop_this_cpu()
   while (num_online_cpus() > 1);         set_online(false);
   proceed... -> hang
				          wbinvd()

WBINVD is an expensive operation and if multiple CPUs issue it at the same
time the resulting delays are even larger.

But CPU0 already observed num_online_cpus() going down to 1 and proceeds
which causes the system to hang.

This issue exists independent of WBINVD, but the delays caused by WBINVD
make it more prominent.

Make this more robust by adding a cpumask which is initialized to the
online CPU mask before sending the IPIs and CPUs clear their bit in
stop_this_cpu() after the WBINVD completed. Check for that cpumask to
become empty in stop_other_cpus() instead of watching num_online_cpus().

The cpumask cannot plug all holes either, but it's better than a raw
counter and allows to restrict the NMI fallback IPI to be sent only the
CPUs which have not reported within the timeout window.

Fixes: 08f253ec37 ("x86/cpu: Clear SME feature flag when not in use")
Reported-by: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/3817d810-e0f1-8ef8-0bbd-663b919ca49b@cybernetics.com
Link: https://lore.kernel.org/r/87h6r770bv.ffs@tglx
2023-06-20 14:51:46 +02:00
Linus Torvalds
2aff7c706c Objtool changes for v6.4:
- Mark arch_cpu_idle_dead() __noreturn, make all architectures & drivers that did
    this inconsistently follow this new, common convention, and fix all the fallout
    that objtool can now detect statically.
 
  - Fix/improve the ORC unwinder becoming unreliable due to UNWIND_HINT_EMPTY ambiguity,
    split it into UNWIND_HINT_END_OF_STACK and UNWIND_HINT_UNDEFINED to resolve it.
 
  - Fix noinstr violations in the KCSAN code and the lkdtm/stackleak code.
 
  - Generate ORC data for __pfx code
 
  - Add more __noreturn annotations to various kernel startup/shutdown/panic functions.
 
  - Misc improvements & fixes.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'objtool-core-2023-04-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool updates from Ingo Molnar:

 - Mark arch_cpu_idle_dead() __noreturn, make all architectures &
   drivers that did this inconsistently follow this new, common
   convention, and fix all the fallout that objtool can now detect
   statically

 - Fix/improve the ORC unwinder becoming unreliable due to
   UNWIND_HINT_EMPTY ambiguity, split it into UNWIND_HINT_END_OF_STACK
   and UNWIND_HINT_UNDEFINED to resolve it

 - Fix noinstr violations in the KCSAN code and the lkdtm/stackleak code

 - Generate ORC data for __pfx code

 - Add more __noreturn annotations to various kernel startup/shutdown
   and panic functions

 - Misc improvements & fixes

* tag 'objtool-core-2023-04-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits)
  x86/hyperv: Mark hv_ghcb_terminate() as noreturn
  scsi: message: fusion: Mark mpt_halt_firmware() __noreturn
  x86/cpu: Mark {hlt,resume}_play_dead() __noreturn
  btrfs: Mark btrfs_assertfail() __noreturn
  objtool: Include weak functions in global_noreturns check
  cpu: Mark nmi_panic_self_stop() __noreturn
  cpu: Mark panic_smp_self_stop() __noreturn
  arm64/cpu: Mark cpu_park_loop() and friends __noreturn
  x86/head: Mark *_start_kernel() __noreturn
  init: Mark start_kernel() __noreturn
  init: Mark [arch_call_]rest_init() __noreturn
  objtool: Generate ORC data for __pfx code
  x86/linkage: Fix padding for typed functions
  objtool: Separate prefix code from stack validation code
  objtool: Remove superfluous dead_end_function() check
  objtool: Add symbol iteration helpers
  objtool: Add WARN_INSN()
  scripts/objdump-func: Support multiple functions
  context_tracking: Fix KCSAN noinstr violation
  objtool: Add stackleak instrumentation to uaccess safe list
  ...
2023-04-28 14:02:54 -07:00
Kirill A. Shutemov
2f8794bd08 x86/mm: Provide arch_prctl() interface for LAM
Add a few of arch_prctl() handles:

 - ARCH_ENABLE_TAGGED_ADDR enabled LAM. The argument is required number
   of tag bits. It is rounded up to the nearest LAM mode that can
   provide it. For now only LAM_U57 is supported, with 6 tag bits.

 - ARCH_GET_UNTAG_MASK returns untag mask. It can indicates where tag
   bits located in the address.

 - ARCH_GET_MAX_TAG_BITS returns the maximum tag bits user can request.
   Zero if LAM is not supported.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/all/20230312112612.31869-9-kirill.shutemov%40linux.intel.com
2023-03-16 13:08:39 -07:00
Kirill A. Shutemov
74c228d20a x86/uaccess: Provide untagged_addr() and remove tags before address check
untagged_addr() is a helper used by the core-mm to strip tag bits and
get the address to the canonical shape based on rules of the current
thread. It only handles userspace addresses.

The untagging mask is stored in per-CPU variable and set on context
switching to the task.

The tags must not be included into check whether it's okay to access the
userspace address. Strip tags in access_ok().

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/all/20230312112612.31869-7-kirill.shutemov%40linux.intel.com
2023-03-16 13:08:39 -07:00
Philippe Mathieu-Daudé
b4c108d7da x86/cpu: Expose arch_cpu_idle_dead()'s prototype definition
Include <linux/cpu.h> to make sure arch_cpu_idle_dead() matches its
prototype going forward.

Inspired-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Link: https://lore.kernel.org/r/20230214083857.50163-1-philmd@linaro.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-03-08 08:44:30 -08:00
Josh Poimboeuf
071c44e427 sched/idle: Mark arch_cpu_idle_dead() __noreturn
Before commit 076cbf5d2163 ("x86/xen: don't let xen_pv_play_dead()
return"), in Xen, when a previously offlined CPU was brought back
online, it unexpectedly resumed execution where it left off in the
middle of the idle loop.

There were some hacks to make that work, but the behavior was surprising
as do_idle() doesn't expect an offlined CPU to return from the dead (in
arch_cpu_idle_dead()).

Now that Xen has been fixed, and the arch-specific implementations of
arch_cpu_idle_dead() also don't return, give it a __noreturn attribute.

This will cause the compiler to complain if an arch-specific
implementation might return.  It also improves code generation for both
caller and callee.

Also fixes the following warning:

  vmlinux.o: warning: objtool: do_idle+0x25f: unreachable instruction

Reported-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/60d527353da8c99d4cf13b6473131d46719ed16d.1676358308.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-03-08 08:44:28 -08:00
Josh Poimboeuf
eab89405b6 x86/cpu: Mark play_dead() __noreturn
play_dead() doesn't return.  Annotate it as such.  By extension this
also makes arch_cpu_idle_dead() noreturn.

Link: https://lore.kernel.org/r/f3a069e6869c51ccfdda656b76882363bc9fcfa4.1676358308.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-03-08 08:44:26 -08:00
Linus Torvalds
2504ba8b01 Power management updates for 6.3-rc1
- Add EPP support to the AMD P-state cpufreq driver (Perry Yuan, Wyes
    Karny, Arnd Bergmann, Bagas Sanjaya).
 
  - Drop the custom cpufreq driver for loongson1 that is not necessary
    any more and the corresponding cpufreq platform device (Keguang
    Zhang).
 
  - Remove "select SRCU" from system sleep, cpufreq and OPP Kconfig
    entries (Paul E. McKenney).
 
  - Enable thermal cooling for Tegra194 (Yi-Wei Wang).
 
  - Register module device table and add missing compatibles for
    cpufreq-qcom-hw (Nícolas F. R. A. Prado, Abel Vesa and Luca Weiss).
 
  - Various dt binding updates for qcom-cpufreq-nvmem and opp-v2-kryo-cpu
    (Christian Marangi).
 
  - Make kobj_type structure in the cpufreq core constant (Thomas
    Weißschuh).
 
  - Make cpufreq_unregister_driver() return void (Uwe Kleine-König).
 
  - Make the TEO cpuidle governor check CPU utilization in order to refine
   idle state selection (Kajetan Puchalski).
 
  - Make Kconfig select the haltpoll cpuidle governor when the haltpoll
    cpuidle driver is selected and replace a default_idle() call in that
    driver with arch_cpu_idle() to allow MWAIT to be used (Li RongQing).
 
  - Add Emerald Rapids Xeon support to the intel_idle driver (Artem
    Bityutskiy).
 
  - Add ARCH_SUSPEND_POSSIBLE dependencies for ARMv4 cpuidle drivers to
    avoid randconfig build failures (Arnd Bergmann).
 
  - Make kobj_type structures used in the cpuidle sysfs interface
    constant (Thomas Weißschuh).
 
  - Make the cpuidle driver registration code update microsecond values
    of idle state parameters in accordance with their nanosecond values
    if they are provided (Rafael Wysocki).
 
  - Make the PSCI cpuidle driver prevent topology CPUs from being
    suspended on PREEMPT_RT (Krzysztof Kozlowski).
 
  - Document that pm_runtime_force_suspend() cannot be used with
    DPM_FLAG_SMART_SUSPEND (Richard Fitzgerald).
 
  - Add EXPORT macros for exporting PM functions from drivers (Richard
    Fitzgerald).
 
  - Remove /** from non-kernel-doc comments in hibernation code (Randy
    Dunlap).
 
  - Fix possible name leak in powercap_register_zone() (Yang Yingliang).
 
  - Add Meteor Lake and Emerald Rapids support to the intel_rapl power
    capping driver (Zhang Rui).
 
  - Modify the idle_inject power capping facility to support 100% idle
    injection (Srinivas Pandruvada).
 
  - Fix large time windows handling in the intel_rapl power capping
    driver (Zhang Rui).
 
  - Fix memory leaks with using debugfs_lookup() in the generic PM
    domains and Energy Model code (Greg Kroah-Hartman).
 
  - Add missing 'cache-unified' property in the example for kryo OPP
    bindings (Rob Herring).
 
  - Fix error checking in opp_migrate_dentry() (Qi Zheng).
 
  - Let qcom,opp-fuse-level be a 2-long array for qcom SoCs (Konrad
    Dybcio).
 
  - Modify some power management utilities to use the canonical ftrace
    path (Ross Zwisler).
 
  - Correct spelling problems for Documentation/power/ as reported by
    codespell (Randy Dunlap).
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Merge tag 'pm-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:
 "These add EPP support to the AMD P-state cpufreq driver, add support
  for new platforms to the Intel RAPL power capping driver, intel_idle
  and the Qualcomm cpufreq driver, enable thermal cooling for Tegra194,
  drop the custom cpufreq driver for loongson1 that is not necessary any
  more (and the corresponding cpufreq platform device), fix assorted
  issues and clean up code.

  Specifics:

   - Add EPP support to the AMD P-state cpufreq driver (Perry Yuan, Wyes
     Karny, Arnd Bergmann, Bagas Sanjaya)

   - Drop the custom cpufreq driver for loongson1 that is not necessary
     any more and the corresponding cpufreq platform device (Keguang
     Zhang)

   - Remove "select SRCU" from system sleep, cpufreq and OPP Kconfig
     entries (Paul E. McKenney)

   - Enable thermal cooling for Tegra194 (Yi-Wei Wang)

   - Register module device table and add missing compatibles for
     cpufreq-qcom-hw (Nícolas F. R. A. Prado, Abel Vesa and Luca Weiss)

   - Various dt binding updates for qcom-cpufreq-nvmem and
     opp-v2-kryo-cpu (Christian Marangi)

   - Make kobj_type structure in the cpufreq core constant (Thomas
     Weißschuh)

   - Make cpufreq_unregister_driver() return void (Uwe Kleine-König)

   - Make the TEO cpuidle governor check CPU utilization in order to
     refine idle state selection (Kajetan Puchalski)

   - Make Kconfig select the haltpoll cpuidle governor when the haltpoll
     cpuidle driver is selected and replace a default_idle() call in
     that driver with arch_cpu_idle() to allow MWAIT to be used (Li
     RongQing)

   - Add Emerald Rapids Xeon support to the intel_idle driver (Artem
     Bityutskiy)

   - Add ARCH_SUSPEND_POSSIBLE dependencies for ARMv4 cpuidle drivers to
     avoid randconfig build failures (Arnd Bergmann)

   - Make kobj_type structures used in the cpuidle sysfs interface
     constant (Thomas Weißschuh)

   - Make the cpuidle driver registration code update microsecond values
     of idle state parameters in accordance with their nanosecond values
     if they are provided (Rafael Wysocki)

   - Make the PSCI cpuidle driver prevent topology CPUs from being
     suspended on PREEMPT_RT (Krzysztof Kozlowski)

   - Document that pm_runtime_force_suspend() cannot be used with
     DPM_FLAG_SMART_SUSPEND (Richard Fitzgerald)

   - Add EXPORT macros for exporting PM functions from drivers (Richard
     Fitzgerald)

   - Remove /** from non-kernel-doc comments in hibernation code (Randy
     Dunlap)

   - Fix possible name leak in powercap_register_zone() (Yang Yingliang)

   - Add Meteor Lake and Emerald Rapids support to the intel_rapl power
     capping driver (Zhang Rui)

   - Modify the idle_inject power capping facility to support 100% idle
     injection (Srinivas Pandruvada)

   - Fix large time windows handling in the intel_rapl power capping
     driver (Zhang Rui)

   - Fix memory leaks with using debugfs_lookup() in the generic PM
     domains and Energy Model code (Greg Kroah-Hartman)

   - Add missing 'cache-unified' property in the example for kryo OPP
     bindings (Rob Herring)

   - Fix error checking in opp_migrate_dentry() (Qi Zheng)

   - Let qcom,opp-fuse-level be a 2-long array for qcom SoCs (Konrad
     Dybcio)

   - Modify some power management utilities to use the canonical ftrace
     path (Ross Zwisler)

   - Correct spelling problems for Documentation/power/ as reported by
     codespell (Randy Dunlap)"

* tag 'pm-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (53 commits)
  Documentation: amd-pstate: disambiguate user space sections
  cpufreq: amd-pstate: Fix invalid write to MSR_AMD_CPPC_REQ
  dt-bindings: opp: opp-v2-kryo-cpu: enlarge opp-supported-hw maximum
  dt-bindings: cpufreq: qcom-cpufreq-nvmem: make cpr bindings optional
  dt-bindings: cpufreq: qcom-cpufreq-nvmem: specify supported opp tables
  PM: Add EXPORT macros for exporting PM functions
  cpuidle: psci: Do not suspend topology CPUs on PREEMPT_RT
  MIPS: loongson32: Drop obsolete cpufreq platform device
  powercap: intel_rapl: Fix handling for large time window
  cpuidle: driver: Update microsecond values of state parameters as needed
  cpuidle: sysfs: make kobj_type structures constant
  cpuidle: add ARCH_SUSPEND_POSSIBLE dependencies
  PM: EM: fix memory leak with using debugfs_lookup()
  PM: domains: fix memory leak with using debugfs_lookup()
  cpufreq: Make kobj_type structure constant
  cpufreq: davinci: Fix clk use after free
  cpufreq: amd-pstate: avoid uninitialized variable use
  cpufreq: Make cpufreq_unregister_driver() return void
  OPP: fix error checking in opp_migrate_dentry()
  dt-bindings: cpufreq: cpufreq-qcom-hw: Add SM8550 compatible
  ...
2023-02-21 12:13:58 -08:00
Li RongQing
716ff71ae2 cpuidle-haltpoll: Replace default_idle() with arch_cpu_idle()
When a KVM guest has MWAIT, mwait_idle() is used as the default idle
function.

However, the cpuidle-haltpoll driver calls default_idle() from
default_enter_idle() directly and that one uses HLT instead of MWAIT,
which may affect performance adversely, because MWAIT is preferred to
HLT as explained by the changelog of commit aebef63cf7 ("x86: Remove
vendor checks from prefer_mwait_c1_over_halt").

Make default_enter_idle() call arch_cpu_idle(), which can use MWAIT,
instead of default_idle() to address this issue.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Li RongQing <lirongqing@baidu.com>
[ rjw: Changelog rewrite ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2023-01-20 17:33:52 +01:00
Peter Zijlstra
89b3098703 arch/idle: Change arch_cpu_idle() behavior: always exit with IRQs disabled
Current arch_cpu_idle() is called with IRQs disabled, but will return
with IRQs enabled.

However, the very first thing the generic code does after calling
arch_cpu_idle() is raw_local_irq_disable(). This means that
architectures that can idle with IRQs disabled end up doing a
pointless 'enable-disable' dance.

Therefore, push this IRQ disabling into the idle function, meaning
that those architectures can avoid the pointless IRQ state flipping.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Acked-by: Mark Rutland <mark.rutland@arm.com> [arm64]
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Guo Ren <guoren@kernel.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195540.618076436@infradead.org
2023-01-13 11:48:15 +01:00
Peter Zijlstra
aaa3896b96 x86/idle: Replace 'x86_idle' function pointer with a static_call
Typical boot time setup; no need to suffer an indirect call for that.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20230112195539.453613251@infradead.org
2023-01-13 11:03:21 +01:00
Linus Torvalds
268325bda5 Random number generator updates for Linux 6.2-rc1.
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Merge tag 'random-6.2-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

Pull random number generator updates from Jason Donenfeld:

 - Replace prandom_u32_max() and various open-coded variants of it,
   there is now a new family of functions that uses fast rejection
   sampling to choose properly uniformly random numbers within an
   interval:

       get_random_u32_below(ceil) - [0, ceil)
       get_random_u32_above(floor) - (floor, U32_MAX]
       get_random_u32_inclusive(floor, ceil) - [floor, ceil]

   Coccinelle was used to convert all current users of
   prandom_u32_max(), as well as many open-coded patterns, resulting in
   improvements throughout the tree.

   I'll have a "late" 6.1-rc1 pull for you that removes the now unused
   prandom_u32_max() function, just in case any other trees add a new
   use case of it that needs to converted. According to linux-next,
   there may be two trivial cases of prandom_u32_max() reintroductions
   that are fixable with a 's/.../.../'. So I'll have for you a final
   conversion patch doing that alongside the removal patch during the
   second week.

   This is a treewide change that touches many files throughout.

 - More consistent use of get_random_canary().

 - Updates to comments, documentation, tests, headers, and
   simplification in configuration.

 - The arch_get_random*_early() abstraction was only used by arm64 and
   wasn't entirely useful, so this has been replaced by code that works
   in all relevant contexts.

 - The kernel will use and manage random seeds in non-volatile EFI
   variables, refreshing a variable with a fresh seed when the RNG is
   initialized. The RNG GUID namespace is then hidden from efivarfs to
   prevent accidental leakage.

   These changes are split into random.c infrastructure code used in the
   EFI subsystem, in this pull request, and related support inside of
   EFISTUB, in Ard's EFI tree. These are co-dependent for full
   functionality, but the order of merging doesn't matter.

 - Part of the infrastructure added for the EFI support is also used for
   an improvement to the way vsprintf initializes its siphash key,
   replacing an sleep loop wart.

 - The hardware RNG framework now always calls its correct random.c
   input function, add_hwgenerator_randomness(), rather than sometimes
   going through helpers better suited for other cases.

 - The add_latent_entropy() function has long been called from the fork
   handler, but is a no-op when the latent entropy gcc plugin isn't
   used, which is fine for the purposes of latent entropy.

   But it was missing out on the cycle counter that was also being mixed
   in beside the latent entropy variable. So now, if the latent entropy
   gcc plugin isn't enabled, add_latent_entropy() will expand to a call
   to add_device_randomness(NULL, 0), which adds a cycle counter,
   without the absent latent entropy variable.

 - The RNG is now reseeded from a delayed worker, rather than on demand
   when used. Always running from a worker allows it to make use of the
   CPU RNG on platforms like S390x, whose instructions are too slow to
   do so from interrupts. It also has the effect of adding in new inputs
   more frequently with more regularity, amounting to a long term
   transcript of random values. Plus, it helps a bit with the upcoming
   vDSO implementation (which isn't yet ready for 6.2).

 - The jitter entropy algorithm now tries to execute on many different
   CPUs, round-robining, in hopes of hitting even more memory latencies
   and other unpredictable effects. It also will mix in a cycle counter
   when the entropy timer fires, in addition to being mixed in from the
   main loop, to account more explicitly for fluctuations in that timer
   firing. And the state it touches is now kept within the same cache
   line, so that it's assured that the different execution contexts will
   cause latencies.

* tag 'random-6.2-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: (23 commits)
  random: include <linux/once.h> in the right header
  random: align entropy_timer_state to cache line
  random: mix in cycle counter when jitter timer fires
  random: spread out jitter callback to different CPUs
  random: remove extraneous period and add a missing one in comments
  efi: random: refresh non-volatile random seed when RNG is initialized
  vsprintf: initialize siphash key using notifier
  random: add back async readiness notifier
  random: reseed in delayed work rather than on-demand
  random: always mix cycle counter in add_latent_entropy()
  hw_random: use add_hwgenerator_randomness() for early entropy
  random: modernize documentation comment on get_random_bytes()
  random: adjust comment to account for removed function
  random: remove early archrandom abstraction
  random: use random.trust_{bootloader,cpu} command line option only
  stackprotector: actually use get_random_canary()
  stackprotector: move get_random_canary() into stackprotector.h
  treewide: use get_random_u32_inclusive() when possible
  treewide: use get_random_u32_{above,below}() instead of manual loop
  treewide: use get_random_u32_below() instead of deprecated function
  ...
2022-12-12 16:22:22 -08:00
Pawan Gupta
6606515742 x86/bugs: Make sure MSR_SPEC_CTRL is updated properly upon resume from S3
The "force" argument to write_spec_ctrl_current() is currently ambiguous
as it does not guarantee the MSR write. This is due to the optimization
that writes to the MSR happen only when the new value differs from the
cached value.

This is fine in most cases, but breaks for S3 resume when the cached MSR
value gets out of sync with the hardware MSR value due to S3 resetting
it.

When x86_spec_ctrl_current is same as x86_spec_ctrl_base, the MSR write
is skipped. Which results in SPEC_CTRL mitigations not getting restored.

Move the MSR write from write_spec_ctrl_current() to a new function that
unconditionally writes to the MSR. Update the callers accordingly and
rename functions.

  [ bp: Rework a bit. ]

Fixes: caa0ff24d5 ("x86/bugs: Keep a per-CPU IA32_SPEC_CTRL value")
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/806d39b0bfec2fe8f50dc5446dff20f5bb24a959.1669821572.git.pawan.kumar.gupta@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-12-02 15:45:33 -08:00
Jason A. Donenfeld
8032bf1233 treewide: use get_random_u32_below() instead of deprecated function
This is a simple mechanical transformation done by:

@@
expression E;
@@
- prandom_u32_max
+ get_random_u32_below
  (E)

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Reviewed-by: SeongJae Park <sj@kernel.org> # for damon
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> # for infiniband
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> # for arm
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-11-18 02:15:15 +01:00
Jason A. Donenfeld
81895a65ec treewide: use prandom_u32_max() when possible, part 1
Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:

@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)

@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@

-       RAND = get_random_u32();
        ... when != RAND
-       RAND %= (E);
+       RAND = prandom_u32_max(E);

// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@

        ((T)get_random_u32()@p & (LITERAL))

// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@

value = None
if literal.startswith('0x'):
        value = int(literal, 16)
elif literal[0] in '123456789':
        value = int(literal, 10)
if value is None:
        print("I don't know how to handle %s" % (literal))
        cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
        print("Skipping 0x%x for cleanup elsewhere" % (value))
        cocci.include_match(False)
elif value & (value + 1) != 0:
        print("Skipping 0x%x because it's not a power of two minus one" % (value))
        cocci.include_match(False)
elif literal.startswith('0x'):
        coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
        coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))

// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@

-       (FUNC()@p & (LITERAL))
+       prandom_u32_max(RESULT)

@collapse_ret@
type T;
identifier VAR;
expression E;
@@

 {
-       T VAR;
-       VAR = (E);
-       return VAR;
+       return E;
 }

@drop_var@
type T;
identifier VAR;
@@

 {
-       T VAR;
        ... when != VAR
 }

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-10-11 17:42:55 -06:00
Linus Torvalds
42efa5e3a8 - Remove the vendor check when selecting MWAIT as the default idle state
- Respect idle=nomwait when supplied on the kernel cmdline
 
 - Two small cleanups
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Merge tag 'x86_cpu_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 cpu updates from Borislav Petkov:

 - Remove the vendor check when selecting MWAIT as the default idle
   state

 - Respect idle=nomwait when supplied on the kernel cmdline

 - Two small cleanups

* tag 'x86_cpu_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu: Use MSR_IA32_MISC_ENABLE constants
  x86: Fix comment for X86_FEATURE_ZEN
  x86: Remove vendor checks from prefer_mwait_c1_over_halt
  x86: Handle idle=nomwait cmdline properly for x86_idle
2022-08-01 09:49:29 -07:00
Peter Zijlstra
c779bc1a90 x86/bugs: Optimize SPEC_CTRL MSR writes
When changing SPEC_CTRL for user control, the WRMSR can be delayed
until return-to-user when KERNEL_IBRS has been enabled.

This avoids an MSR write during context switch.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:59 +02:00
Peter Zijlstra
caa0ff24d5 x86/bugs: Keep a per-CPU IA32_SPEC_CTRL value
Due to TIF_SSBD and TIF_SPEC_IB the actual IA32_SPEC_CTRL value can
differ from x86_spec_ctrl_base. As such, keep a per-CPU value
reflecting the current task's MSR content.

  [jpoimboe: rename]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-27 10:33:59 +02:00
Wyes Karny
aebef63cf7 x86: Remove vendor checks from prefer_mwait_c1_over_halt
Remove vendor checks from prefer_mwait_c1_over_halt function. Restore
the decision tree to support MWAIT C1 as the default idle state based on
CPUID checks as done by Thomas Gleixner in
commit 09fd4b4ef5 ("x86: use cpuid to check MWAIT support for C1")

The decision tree is removed in
commit 69fb3676df ("x86 idle: remove mwait_idle() and "idle=mwait" cmdline param")

Prefer MWAIT when the following conditions are satisfied:
    1. CPUID_Fn00000001_ECX [Monitor] should be set
    2. CPUID_Fn00000005 should be supported
    3. If CPUID_Fn00000005_ECX [EMX] is set then there should be
       at least one C1 substate available, indicated by
       CPUID_Fn00000005_EDX [MWaitC1SubStates] bits.

Otherwise use HLT for default_idle function.

HPC customers who want to optimize for lower latency are known to
disable Global C-States in the BIOS. In fact, some vendors allow
choosing a BIOS 'performance' profile which explicitly disables
C-States.  In this scenario, the cpuidle driver will not be loaded and
the kernel will continue with the default idle state chosen at boot
time. On AMD systems currently the default idle state is HLT which has
a higher exit latency compared to MWAIT.

The reason for the choice of HLT over MWAIT on AMD systems is:

1. Families prior to 10h didn't support MWAIT
2. Families 10h-15h supported MWAIT, but not MWAIT C1. Hence it was
   preferable to use HLT as the default state on these systems.

However, AMD Family 17h onwards supports MWAIT as well as MWAIT C1. And
it is preferable to use MWAIT as the default idle state on these
systems, as it has lower exit latencies.

The below table represents the exit latency for HLT and MWAIT on AMD
Zen 3 system. Exit latency is measured by issuing a wakeup (IPI) to
other CPU and measuring how many clock cycles it took to wakeup.  Each
iteration measures 10K wakeups by pinning source and destination.

HLT:

25.0000th percentile  :      1900 ns
50.0000th percentile  :      2000 ns
75.0000th percentile  :      2300 ns
90.0000th percentile  :      2500 ns
95.0000th percentile  :      2600 ns
99.0000th percentile  :      2800 ns
99.5000th percentile  :      3000 ns
99.9000th percentile  :      3400 ns
99.9500th percentile  :      3600 ns
99.9900th percentile  :      5900 ns
  Min latency         :      1700 ns
  Max latency         :      5900 ns
Total Samples      9999

MWAIT:

25.0000th percentile  :      1400 ns
50.0000th percentile  :      1500 ns
75.0000th percentile  :      1700 ns
90.0000th percentile  :      1800 ns
95.0000th percentile  :      1900 ns
99.0000th percentile  :      2300 ns
99.5000th percentile  :      2500 ns
99.9000th percentile  :      3200 ns
99.9500th percentile  :      3500 ns
99.9900th percentile  :      4600 ns
  Min latency         :      1200 ns
  Max latency         :      4600 ns
Total Samples      9997

Improvement (99th percentile): 21.74%

Below is another result for context_switch2 micro-benchmark, which
brings out the impact of improved wakeup latency through increased
context-switches per second.

with HLT:
-------------------------------
50.0000th percentile  :  190184
75.0000th percentile  :  191032
90.0000th percentile  :  192314
95.0000th percentile  :  192520
99.0000th percentile  :  192844
MIN  :  190148
MAX  :  192852

with MWAIT:
-------------------------------
50.0000th percentile  :  277444
75.0000th percentile  :  278268
90.0000th percentile  :  278888
95.0000th percentile  :  279164
99.0000th percentile  :  280504
MIN  :  273278
MAX  :  281410

Improvement(99th percentile): ~ 45.46%

Signed-off-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Link: https://ozlabs.org/~anton/junkcode/context_switch2.c
Link: https://lkml.kernel.org/r/0cc675d8fd1f55e41b510e10abf2e21b6e9803d5.1654538381.git-series.wyes.karny@amd.com
2022-06-08 13:00:19 -07:00
Wyes Karny
8bcedb4ce0 x86: Handle idle=nomwait cmdline properly for x86_idle
When kernel is booted with idle=nomwait do not use MWAIT as the
default idle state.

If the user boots the kernel with idle=nomwait, it is a clear
direction to not use mwait as the default idle state.
However, the current code does not take this into consideration
while selecting the default idle state on x86.

Fix it by checking for the idle=nomwait boot option in
prefer_mwait_c1_over_halt().

Also update the documentation around idle=nomwait appropriately.

[ dhansen: tweak commit message ]

Signed-off-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lkml.kernel.org/r/fdc2dc2d0a1bc21c2f53d989ea2d2ee3ccbc0dbe.1654538381.git-series.wyes.karny@amd.com
2022-06-08 12:58:58 -07:00
Linus Torvalds
1ec6574a3c This set of changes updates init and user mode helper tasks to be
ordinary user mode tasks.
 
 In commit 40966e316f ("kthread: Ensure struct kthread is present for
 all kthreads") caused init and the user mode helper threads that call
 kernel_execve to have struct kthread allocated for them.  This struct
 kthread going away during execve in turned made a use after free of
 struct kthread possible.
 
 The commit 343f4c49f2 ("kthread: Don't allocate kthread_struct for
 init and umh") is enough to fix the use after free and is simple enough
 to be backportable.
 
 The rest of the changes pass struct kernel_clone_args to clean things
 up and cause the code to make sense.
 
 In making init and the user mode helpers tasks purely user mode tasks
 I ran into two complications.  The function task_tick_numa was
 detecting tasks without an mm by testing for the presence of
 PF_KTHREAD.  The initramfs code in populate_initrd_image was using
 flush_delayed_fput to ensuere the closing of all it's file descriptors
 was complete, and flush_delayed_fput does not work in a userspace thread.
 
 I have looked and looked and more complications and in my code review
 I have not found any, and neither has anyone else with the code sitting
 in linux-next.
 
 Link: https://lkml.kernel.org/r/87mtfu4up3.fsf@email.froward.int.ebiederm.org
 
 Eric W. Biederman (8):
       kthread: Don't allocate kthread_struct for init and umh
       fork: Pass struct kernel_clone_args into copy_thread
       fork: Explicity test for idle tasks in copy_thread
       fork: Generalize PF_IO_WORKER handling
       init: Deal with the init process being a user mode process
       fork: Explicitly set PF_KTHREAD
       fork: Stop allowing kthreads to call execve
       sched: Update task_tick_numa to ignore tasks without an mm
 
  arch/alpha/kernel/process.c      | 13 ++++++------
  arch/arc/kernel/process.c        | 13 ++++++------
  arch/arm/kernel/process.c        | 12 ++++++-----
  arch/arm64/kernel/process.c      | 12 ++++++-----
  arch/csky/kernel/process.c       | 15 ++++++-------
  arch/h8300/kernel/process.c      | 10 ++++-----
  arch/hexagon/kernel/process.c    | 12 ++++++-----
  arch/ia64/kernel/process.c       | 15 +++++++------
  arch/m68k/kernel/process.c       | 12 ++++++-----
  arch/microblaze/kernel/process.c | 12 ++++++-----
  arch/mips/kernel/process.c       | 13 ++++++------
  arch/nios2/kernel/process.c      | 12 ++++++-----
  arch/openrisc/kernel/process.c   | 12 ++++++-----
  arch/parisc/kernel/process.c     | 18 +++++++++-------
  arch/powerpc/kernel/process.c    | 15 +++++++------
  arch/riscv/kernel/process.c      | 12 ++++++-----
  arch/s390/kernel/process.c       | 12 ++++++-----
  arch/sh/kernel/process_32.c      | 12 ++++++-----
  arch/sparc/kernel/process_32.c   | 12 ++++++-----
  arch/sparc/kernel/process_64.c   | 12 ++++++-----
  arch/um/kernel/process.c         | 15 +++++++------
  arch/x86/include/asm/fpu/sched.h |  2 +-
  arch/x86/include/asm/switch_to.h |  8 +++----
  arch/x86/kernel/fpu/core.c       |  4 ++--
  arch/x86/kernel/process.c        | 18 +++++++++-------
  arch/xtensa/kernel/process.c     | 17 ++++++++-------
  fs/exec.c                        |  8 ++++---
  include/linux/sched/task.h       |  8 +++++--
  init/initramfs.c                 |  2 ++
  init/main.c                      |  2 +-
  kernel/fork.c                    | 46 +++++++++++++++++++++++++++++++++-------
  kernel/sched/fair.c              |  2 +-
  kernel/umh.c                     |  6 +++---
  33 files changed, 234 insertions(+), 160 deletions(-)
 
 Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Merge tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull kthread updates from Eric Biederman:
 "This updates init and user mode helper tasks to be ordinary user mode
  tasks.

  Commit 40966e316f ("kthread: Ensure struct kthread is present for
  all kthreads") caused init and the user mode helper threads that call
  kernel_execve to have struct kthread allocated for them. This struct
  kthread going away during execve in turned made a use after free of
  struct kthread possible.

  Here, commit 343f4c49f2 ("kthread: Don't allocate kthread_struct for
  init and umh") is enough to fix the use after free and is simple
  enough to be backportable.

  The rest of the changes pass struct kernel_clone_args to clean things
  up and cause the code to make sense.

  In making init and the user mode helpers tasks purely user mode tasks
  I ran into two complications. The function task_tick_numa was
  detecting tasks without an mm by testing for the presence of
  PF_KTHREAD. The initramfs code in populate_initrd_image was using
  flush_delayed_fput to ensuere the closing of all it's file descriptors
  was complete, and flush_delayed_fput does not work in a userspace
  thread.

  I have looked and looked and more complications and in my code review
  I have not found any, and neither has anyone else with the code
  sitting in linux-next"

* tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  sched: Update task_tick_numa to ignore tasks without an mm
  fork: Stop allowing kthreads to call execve
  fork: Explicitly set PF_KTHREAD
  init: Deal with the init process being a user mode process
  fork: Generalize PF_IO_WORKER handling
  fork: Explicity test for idle tasks in copy_thread
  fork: Pass struct kernel_clone_args into copy_thread
  kthread: Don't allocate kthread_struct for init and umh
2022-06-03 16:03:05 -07:00
Linus Torvalds
3e2cbc016b - Add Raptor Lake to the set of CPU models which support splitlock
- Make life miserable for apps using split locks by slowing them down
 considerably while the rest of the system remains responsive. The hope
 is it will hurt more and people will really fix their misaligned locks
 apps. As a result, free a TIF bit.
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Merge tag 'x86_splitlock_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 splitlock updates from Borislav Petkov:

 - Add Raptor Lake to the set of CPU models which support splitlock

 - Make life miserable for apps using split locks by slowing them down
   considerably while the rest of the system remains responsive. The
   hope is it will hurt more and people will really fix their misaligned
   locks apps. As a result, free a TIF bit.

* tag 'x86_splitlock_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/split_lock: Enable the split lock feature on Raptor Lake
  x86/split-lock: Remove unused TIF_SLD bit
  x86/split_lock: Make life miserable for split lockers
2022-05-23 19:24:47 -07:00
Linus Torvalds
de8ac81747 - Remove all the code around GS switching on 32-bit now that it is not
needed anymore
 
 - Other misc improvements
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Merge tag 'x86_core_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core x86 updates from Borislav Petkov:

 - Remove all the code around GS switching on 32-bit now that it is not
   needed anymore

 - Other misc improvements

* tag 'x86_core_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  bug: Use normal relative pointers in 'struct bug_entry'
  x86/nmi: Make register_nmi_handler() more robust
  x86/asm: Merge load_gs_index()
  x86/32: Remove lazy GS macros
  ELF: Remove elf_core_copy_kernel_regs()
  x86/32: Simplify ELF_CORE_COPY_REGS
2022-05-23 18:42:07 -07:00
Linus Torvalds
a13dc4d409 - Serious sanitization and cleanup of the whole APERF/MPERF and
frequency invariance code along with removing the need for unnecessary IPIs
 
 - Finally remove a.out support
 
 - The usual trivial cleanups and fixes all over x86
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Merge tag 'x86_cleanups_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 cleanups from Borislav Petkov:

 - Serious sanitization and cleanup of the whole APERF/MPERF and
   frequency invariance code along with removing the need for
   unnecessary IPIs

 - Finally remove a.out support

 - The usual trivial cleanups and fixes all over x86

* tag 'x86_cleanups_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
  x86: Remove empty files
  x86/speculation: Add missing srbds=off to the mitigations= help text
  x86/prctl: Remove pointless task argument
  x86/aperfperf: Make it correct on 32bit and UP kernels
  x86/aperfmperf: Integrate the fallback code from show_cpuinfo()
  x86/aperfmperf: Replace arch_freq_get_on_cpu()
  x86/aperfmperf: Replace aperfmperf_get_khz()
  x86/aperfmperf: Store aperf/mperf data for cpu frequency reads
  x86/aperfmperf: Make parts of the frequency invariance code unconditional
  x86/aperfmperf: Restructure arch_scale_freq_tick()
  x86/aperfmperf: Put frequency invariance aperf/mperf data into a struct
  x86/aperfmperf: Untangle Intel and AMD frequency invariance init
  x86/aperfmperf: Separate AP/BP frequency invariance init
  x86/smp: Move APERF/MPERF code where it belongs
  x86/aperfmperf: Dont wake idle CPUs in arch_freq_get_on_cpu()
  x86/process: Fix kernel-doc warning due to a changed function name
  x86: Remove a.out support
  x86/mm: Replace nodes_weight() with nodes_empty() where appropriate
  x86: Replace cpumask_weight() with cpumask_empty() where appropriate
  x86/pkeys: Remove __arch_set_user_pkey_access() declaration
  ...
2022-05-23 18:17:09 -07:00
Thomas Gleixner
f5c0b4f304 x86/prctl: Remove pointless task argument
The functions invoked via do_arch_prctl_common() can only operate on
the current task and none of these function uses the task argument.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/87lev7vtxj.ffs@tglx
2022-05-13 12:56:28 +02:00
Eric W. Biederman
5bd2e97c86 fork: Generalize PF_IO_WORKER handling
Add fn and fn_arg members into struct kernel_clone_args and test for
them in copy_thread (instead of testing for PF_KTHREAD | PF_IO_WORKER).
This allows any task that wants to be a user space task that only runs
in kernel mode to use this functionality.

The code on x86 is an exception and still retains a PF_KTHREAD test
because x86 unlikely everything else handles kthreads slightly
differently than user space tasks that start with a function.

The functions that created tasks that start with a function
have been updated to set ".fn" and ".fn_arg" instead of
".stack" and ".stack_size".  These functions are fork_idle(),
create_io_thread(), kernel_thread(), and user_mode_thread().

Link: https://lkml.kernel.org/r/20220506141512.516114-4-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-07 09:01:59 -05:00
Eric W. Biederman
c5febea095 fork: Pass struct kernel_clone_args into copy_thread
With io_uring we have started supporting tasks that are for most
purposes user space tasks that exclusively run code in kernel mode.

The kernel task that exec's init and tasks that exec user mode
helpers are also user mode tasks that just run kernel code
until they call kernel execve.

Pass kernel_clone_args into copy_thread so these oddball
tasks can be supported more cleanly and easily.

v2: Fix spelling of kenrel_clone_args on h8300
Link: https://lkml.kernel.org/r/20220506141512.516114-2-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-07 09:01:48 -05:00
Tony Luck
ef79970d7c x86/split-lock: Remove unused TIF_SLD bit
Changes to the "warn" mode of split lock handling mean that TIF_SLD is
never set.

Remove the bit, and the functions that use it.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220310204854.31752-3-tony.luck@intel.com
2022-04-27 15:43:39 +02:00
Brian Gerst
3a24a60854 x86/32: Remove lazy GS macros
GS is always a user segment now.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220325153953.162643-4-brgerst@gmail.com
2022-04-14 14:09:43 +02:00
Jiapeng Chong
dbb5ab6d2c x86/process: Fix kernel-doc warning due to a changed function name
Fix the following scripts/kernel-doc warning:

  arch/x86/kernel/process.c:412: warning: expecting prototype for tss_update_io_bitmap().
  Prototype was for native_tss_update_io_bitmap() instead.

  [ bp: Massage. ]

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220414062110.60343-1-jiapeng.chong@linux.alibaba.com
2022-04-14 12:23:06 +02:00
Kirill A. Shutemov
bfe6ed0c67 x86/tdx: Add HLT support for TDX guests
The HLT instruction is a privileged instruction, executing it stops
instruction execution and places the processor in a HALT state. It
is used in kernel for cases like reboot, idle loop and exception fixup
handlers. For the idle case, interrupts will be enabled (using STI)
before the HLT instruction (this is also called safe_halt()).

To support the HLT instruction in TDX guests, it needs to be emulated
using TDVMCALL (hypercall to VMM). More details about it can be found
in Intel Trust Domain Extensions (Intel TDX) Guest-Host-Communication
Interface (GHCI) specification, section TDVMCALL[Instruction.HLT].

In TDX guests, executing HLT instruction will generate a #VE, which is
used to emulate the HLT instruction. But #VE based emulation will not
work for the safe_halt() flavor, because it requires STI instruction to
be executed just before the TDCALL. Since idle loop is the only user of
safe_halt() variant, handle it as a special case.

To avoid *safe_halt() call in the idle function, define the
tdx_guest_idle() and use it to override the "x86_idle" function pointer
for a valid TDX guest.

Alternative choices like PV ops have been considered for adding
safe_halt() support. But it was rejected because HLT paravirt calls
only exist under PARAVIRT_XXL, and enabling it in TDX guest just for
safe_halt() use case is not worth the cost.

Co-developed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20220405232939.73860-9-kirill.shutemov@linux.intel.com
2022-04-07 08:27:51 -07:00
Ingo Molnar
9cea0d46f5 Merge branch 'x86/cpu' into x86/core, to resolve conflicts
Conflicts:
	arch/x86/include/asm/cpufeatures.h

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2022-03-15 12:52:51 +01:00
Peter Zijlstra
f9cdf7ca57 x86: Mark stop_this_cpu() __noreturn
vmlinux.o: warning: objtool: smp_stop_nmi_callback()+0x2b: unreachable instruction

0000 0000000000047cf0 <smp_stop_nmi_callback>:
...
0026    47d16:  e8 00 00 00 00          call   47d1b <smp_stop_nmi_callback+0x2b>       47d17: R_X86_64_PLT32   stop_this_cpu-0x4
002b    47d1b:  b8 01 00 00 00          mov    $0x1,%eax

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154319.290905453@infradead.org
2022-03-15 10:32:43 +01:00
Mario Limonciello
08f253ec37 x86/cpu: Clear SME feature flag when not in use
Currently, the SME CPU feature flag is reflective of whether the CPU
supports the feature but not whether it has been activated by the
kernel.

Change this around to clear the SME feature flag if the kernel is not
using it so userspace can determine if it is available and in use
from /proc/cpuinfo.

As the feature flag is cleared on systems where SME isn't active, use
CPUID 0x8000001f to confirm SME availability before calling
native_wbinvd().

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20220216034446.2430634-1-mario.limonciello@amd.com
2022-02-16 19:45:53 +01:00
Linus Torvalds
79e06c4c49 RISCV:
- Use common KVM implementation of MMU memory caches
 
 - SBI v0.2 support for Guest
 
 - Initial KVM selftests support
 
 - Fix to avoid spurious virtual interrupts after clearing hideleg CSR
 
 - Update email address for Anup and Atish
 
 ARM:
 - Simplification of the 'vcpu first run' by integrating it into
   KVM's 'pid change' flow
 
 - Refactoring of the FP and SVE state tracking, also leading to
   a simpler state and less shared data between EL1 and EL2 in
   the nVHE case
 
 - Tidy up the header file usage for the nvhe hyp object
 
 - New HYP unsharing mechanism, finally allowing pages to be
   unmapped from the Stage-1 EL2 page-tables
 
 - Various pKVM cleanups around refcounting and sharing
 
 - A couple of vgic fixes for bugs that would trigger once
   the vcpu xarray rework is merged, but not sooner
 
 - Add minimal support for ARMv8.7's PMU extension
 
 - Rework kvm_pgtable initialisation ahead of the NV work
 
 - New selftest for IRQ injection
 
 - Teach selftests about the lack of default IPA space and
   page sizes
 
 - Expand sysreg selftest to deal with Pointer Authentication
 
 - The usual bunch of cleanups and doc update
 
 s390:
 - fix sigp sense/start/stop/inconsistency
 
 - cleanups
 
 x86:
 - Clean up some function prototypes more
 
 - improved gfn_to_pfn_cache with proper invalidation, used by Xen emulation
 
 - add KVM_IRQ_ROUTING_XEN_EVTCHN and event channel delivery
 
 - completely remove potential TOC/TOU races in nested SVM consistency checks
 
 - update some PMCs on emulated instructions
 
 - Intel AMX support (joint work between Thomas and Intel)
 
 - large MMU cleanups
 
 - module parameter to disable PMU virtualization
 
 - cleanup register cache
 
 - first part of halt handling cleanups
 
 - Hyper-V enlightened MSR bitmap support for nested hypervisors
 
 Generic:
 - clean up Makefiles
 
 - introduce CONFIG_HAVE_KVM_DIRTY_RING
 
 - optimize memslot lookup using a tree
 
 - optimize vCPU array usage by converting to xarray
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "RISCV:

   - Use common KVM implementation of MMU memory caches

   - SBI v0.2 support for Guest

   - Initial KVM selftests support

   - Fix to avoid spurious virtual interrupts after clearing hideleg CSR

   - Update email address for Anup and Atish

  ARM:

   - Simplification of the 'vcpu first run' by integrating it into KVM's
     'pid change' flow

   - Refactoring of the FP and SVE state tracking, also leading to a
     simpler state and less shared data between EL1 and EL2 in the nVHE
     case

   - Tidy up the header file usage for the nvhe hyp object

   - New HYP unsharing mechanism, finally allowing pages to be unmapped
     from the Stage-1 EL2 page-tables

   - Various pKVM cleanups around refcounting and sharing

   - A couple of vgic fixes for bugs that would trigger once the vcpu
     xarray rework is merged, but not sooner

   - Add minimal support for ARMv8.7's PMU extension

   - Rework kvm_pgtable initialisation ahead of the NV work

   - New selftest for IRQ injection

   - Teach selftests about the lack of default IPA space and page sizes

   - Expand sysreg selftest to deal with Pointer Authentication

   - The usual bunch of cleanups and doc update

  s390:

   - fix sigp sense/start/stop/inconsistency

   - cleanups

  x86:

   - Clean up some function prototypes more

   - improved gfn_to_pfn_cache with proper invalidation, used by Xen
     emulation

   - add KVM_IRQ_ROUTING_XEN_EVTCHN and event channel delivery

   - completely remove potential TOC/TOU races in nested SVM consistency
     checks

   - update some PMCs on emulated instructions

   - Intel AMX support (joint work between Thomas and Intel)

   - large MMU cleanups

   - module parameter to disable PMU virtualization

   - cleanup register cache

   - first part of halt handling cleanups

   - Hyper-V enlightened MSR bitmap support for nested hypervisors

  Generic:

   - clean up Makefiles

   - introduce CONFIG_HAVE_KVM_DIRTY_RING

   - optimize memslot lookup using a tree

   - optimize vCPU array usage by converting to xarray"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (268 commits)
  x86/fpu: Fix inline prefix warnings
  selftest: kvm: Add amx selftest
  selftest: kvm: Move struct kvm_x86_state to header
  selftest: kvm: Reorder vcpu_load_state steps for AMX
  kvm: x86: Disable interception for IA32_XFD on demand
  x86/fpu: Provide fpu_sync_guest_vmexit_xfd_state()
  kvm: selftests: Add support for KVM_CAP_XSAVE2
  kvm: x86: Add support for getting/setting expanded xstate buffer
  x86/fpu: Add uabi_size to guest_fpu
  kvm: x86: Add CPUID support for Intel AMX
  kvm: x86: Add XCR0 support for Intel AMX
  kvm: x86: Disable RDMSR interception of IA32_XFD_ERR
  kvm: x86: Emulate IA32_XFD_ERR for guest
  kvm: x86: Intercept #NM for saving IA32_XFD_ERR
  x86/fpu: Prepare xfd_err in struct fpu_guest
  kvm: x86: Add emulation for IA32_XFD
  x86/fpu: Provide fpu_update_guest_xfd() for IA32_XFD emulation
  kvm: x86: Enable dynamic xfeatures at KVM_SET_CPUID2
  x86/fpu: Provide fpu_enable_guest_xfd_features() for KVM
  x86/fpu: Add guest support to xfd_enable_feature()
  ...
2022-01-16 16:15:14 +02:00