<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/arch/x86/kernel/cpu/common.c, branch v6.6</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>x86/srso: Add SRSO mitigation for Hygon processors</title>
<updated>2023-09-28T07:57:07+00:00</updated>
<author>
<name>Pu Wen</name>
<email>puwen@hygon.cn</email>
</author>
<published>2023-09-28T06:59:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=a5ef7d68cea1344cf524f04981c2b3f80bedbb0d'/>
<id>a5ef7d68cea1344cf524f04981c2b3f80bedbb0d</id>
<content type='text'>
Add mitigation for the speculative return stack overflow vulnerability
which exists on Hygon processors too.

Signed-off-by: Pu Wen &lt;puwen@hygon.cn&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Acked-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/tencent_4A14812842F104E93AA722EC939483CEFF05@qq.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add mitigation for the speculative return stack overflow vulnerability
which exists on Hygon processors too.

Signed-off-by: Pu Wen &lt;puwen@hygon.cn&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Acked-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/tencent_4A14812842F104E93AA722EC939483CEFF05@qq.com
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'x86-urgent-2023-09-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2023-09-01T23:40:19+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-09-01T23:40:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=2fcbb03847d89155d7b33d75ffee3a6bc5c51c97'/>
<id>2fcbb03847d89155d7b33d75ffee3a6bc5c51c97</id>
<content type='text'>
Pull x86 fixes from Dave Hansen:
 "The most important fix here adds a missing CPU model to the recent
  Gather Data Sampling (GDS) mitigation list to ensure that mitigations
  are available on that CPU.

  There are also a pair of warning fixes, and closure of a covert
  channel that pops up when protection keys are disabled.

  Summary:
   - Mark all Skylake CPUs as vulnerable to GDS
   - Fix PKRU covert channel
   - Fix -Wmissing-variable-declarations warning for ia32_xyz_class
   - Fix kernel-doc annotation warning"

* tag 'x86-urgent-2023-09-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/fpu/xstate: Fix PKRU covert channel
  x86/irq/i8259: Fix kernel-doc annotation warning
  x86/speculation: Mark all Skylake CPUs as vulnerable to GDS
  x86/audit: Fix -Wmissing-variable-declarations warning for ia32_xyz_class
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull x86 fixes from Dave Hansen:
 "The most important fix here adds a missing CPU model to the recent
  Gather Data Sampling (GDS) mitigation list to ensure that mitigations
  are available on that CPU.

  There are also a pair of warning fixes, and closure of a covert
  channel that pops up when protection keys are disabled.

  Summary:
   - Mark all Skylake CPUs as vulnerable to GDS
   - Fix PKRU covert channel
   - Fix -Wmissing-variable-declarations warning for ia32_xyz_class
   - Fix kernel-doc annotation warning"

* tag 'x86-urgent-2023-09-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/fpu/xstate: Fix PKRU covert channel
  x86/irq/i8259: Fix kernel-doc annotation warning
  x86/speculation: Mark all Skylake CPUs as vulnerable to GDS
  x86/audit: Fix -Wmissing-variable-declarations warning for ia32_xyz_class
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2023-08-31T19:20:12+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-08-31T19:20:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=df57721f9a63e8a1fb9b9b2e70de4aa4c7e0cd2e'/>
<id>df57721f9a63e8a1fb9b9b2e70de4aa4c7e0cd2e</id>
<content type='text'>
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
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/speculation: Mark all Skylake CPUs as vulnerable to GDS</title>
<updated>2023-08-31T18:20:31+00:00</updated>
<author>
<name>Dave Hansen</name>
<email>dave.hansen@linux.intel.com</email>
</author>
<published>2023-08-29T15:07:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c9f4c45c8ec3f07f4f083f9750032a1ec3eab6b2'/>
<id>c9f4c45c8ec3f07f4f083f9750032a1ec3eab6b2</id>
<content type='text'>
The Gather Data Sampling (GDS) vulnerability is common to all Skylake
processors.  However, the "client" Skylakes* are now in this list:

	https://www.intel.com/content/www/us/en/support/articles/000022396/processors.html

which means they are no longer included for new vulnerabilities here:

	https://www.intel.com/content/www/us/en/developer/topic-technology/software-security-guidance/processors-affected-consolidated-product-cpu-model.html

or in other GDS documentation.  Thus, they were not included in the
original GDS mitigation patches.

Mark SKYLAKE and SKYLAKE_L as vulnerable to GDS to match all the
other Skylake CPUs (which include Kaby Lake).  Also group the CPUs
so that the ones that share the exact same vulnerabilities are next
to each other.

Last, move SRBDS to the end of each line.  This makes it clear at a
glance that SKYLAKE_X is unique.  Of the five Skylakes, it is the
only "server" CPU and has a different implementation from the
clients of the "special register" hardware, making it immune to SRBDS.

This makes the diff much harder to read, but the resulting table is
worth it.

I very much appreciate the report from Michael Zhivich about this
issue.  Despite what level of support a hardware vendor is providing,
the kernel very much needs an accurate and up-to-date list of
vulnerable CPUs.  More reports like this are very welcome.

* Client Skylakes are CPUID 406E3/506E3 which is family 6, models
  0x4E and 0x5E, aka INTEL_FAM6_SKYLAKE and INTEL_FAM6_SKYLAKE_L.

Reported-by: Michael Zhivich &lt;mzhivich@akamai.com&gt;
Fixes: 8974eb588283 ("x86/speculation: Add Gather Data Sampling mitigation")
Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Reviewed-by: Daniel Sneddon &lt;daniel.sneddon@linux.intel.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The Gather Data Sampling (GDS) vulnerability is common to all Skylake
processors.  However, the "client" Skylakes* are now in this list:

	https://www.intel.com/content/www/us/en/support/articles/000022396/processors.html

which means they are no longer included for new vulnerabilities here:

	https://www.intel.com/content/www/us/en/developer/topic-technology/software-security-guidance/processors-affected-consolidated-product-cpu-model.html

or in other GDS documentation.  Thus, they were not included in the
original GDS mitigation patches.

Mark SKYLAKE and SKYLAKE_L as vulnerable to GDS to match all the
other Skylake CPUs (which include Kaby Lake).  Also group the CPUs
so that the ones that share the exact same vulnerabilities are next
to each other.

Last, move SRBDS to the end of each line.  This makes it clear at a
glance that SKYLAKE_X is unique.  Of the five Skylakes, it is the
only "server" CPU and has a different implementation from the
clients of the "special register" hardware, making it immune to SRBDS.

This makes the diff much harder to read, but the resulting table is
worth it.

I very much appreciate the report from Michael Zhivich about this
issue.  Despite what level of support a hardware vendor is providing,
the kernel very much needs an accurate and up-to-date list of
vulnerable CPUs.  More reports like this are very welcome.

* Client Skylakes are CPUID 406E3/506E3 which is family 6, models
  0x4E and 0x5E, aka INTEL_FAM6_SKYLAKE and INTEL_FAM6_SKYLAKE_L.

Reported-by: Michael Zhivich &lt;mzhivich@akamai.com&gt;
Fixes: 8974eb588283 ("x86/speculation: Add Gather Data Sampling mitigation")
Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Reviewed-by: Daniel Sneddon &lt;daniel.sneddon@linux.intel.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'x86_apic_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2023-08-30T17:44:46+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-08-30T17:44:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=1687d8aca5488674686eb46bf49d1d908b2672a1'/>
<id>1687d8aca5488674686eb46bf49d1d908b2672a1</id>
<content type='text'>
Pull x86 apic updates from Dave Hansen:
 "This includes a very thorough rework of the 'struct apic' handlers.
  Quite a variety of them popped up over the years, especially in the
  32-bit days when odd apics were much more in vogue.

  The end result speaks for itself, which is a removal of a ton of code
  and static calls to replace indirect calls.

  If there's any breakage here, it's likely to be around the 32-bit
  museum pieces that get light to no testing these days.

  Summary:

   - Rework apic callbacks, getting rid of unnecessary ones and
     coalescing lots of silly duplicates.

   - Use static_calls() instead of indirect calls for apic-&gt;foo()

   - Tons of cleanups an crap removal along the way"

* tag 'x86_apic_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
  x86/apic: Turn on static calls
  x86/apic: Provide static call infrastructure for APIC callbacks
  x86/apic: Wrap IPI calls into helper functions
  x86/apic: Mark all hotpath APIC callback wrappers __always_inline
  x86/xen/apic: Mark apic __ro_after_init
  x86/apic: Convert other overrides to apic_update_callback()
  x86/apic: Replace acpi_wake_cpu_handler_update() and apic_set_eoi_cb()
  x86/apic: Provide apic_update_callback()
  x86/xen/apic: Use standard apic driver mechanism for Xen PV
  x86/apic: Provide common init infrastructure
  x86/apic: Wrap apic-&gt;native_eoi() into a helper
  x86/apic: Nuke ack_APIC_irq()
  x86/apic: Remove pointless arguments from [native_]eoi_write()
  x86/apic/noop: Tidy up the code
  x86/apic: Remove pointless NULL initializations
  x86/apic: Sanitize APIC ID range validation
  x86/apic: Prepare x2APIC for using apic::max_apic_id
  x86/apic: Simplify X2APIC ID validation
  x86/apic: Add max_apic_id member
  x86/apic: Wrap APIC ID validation into an inline
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull x86 apic updates from Dave Hansen:
 "This includes a very thorough rework of the 'struct apic' handlers.
  Quite a variety of them popped up over the years, especially in the
  32-bit days when odd apics were much more in vogue.

  The end result speaks for itself, which is a removal of a ton of code
  and static calls to replace indirect calls.

  If there's any breakage here, it's likely to be around the 32-bit
  museum pieces that get light to no testing these days.

  Summary:

   - Rework apic callbacks, getting rid of unnecessary ones and
     coalescing lots of silly duplicates.

   - Use static_calls() instead of indirect calls for apic-&gt;foo()

   - Tons of cleanups an crap removal along the way"

* tag 'x86_apic_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
  x86/apic: Turn on static calls
  x86/apic: Provide static call infrastructure for APIC callbacks
  x86/apic: Wrap IPI calls into helper functions
  x86/apic: Mark all hotpath APIC callback wrappers __always_inline
  x86/xen/apic: Mark apic __ro_after_init
  x86/apic: Convert other overrides to apic_update_callback()
  x86/apic: Replace acpi_wake_cpu_handler_update() and apic_set_eoi_cb()
  x86/apic: Provide apic_update_callback()
  x86/xen/apic: Use standard apic driver mechanism for Xen PV
  x86/apic: Provide common init infrastructure
  x86/apic: Wrap apic-&gt;native_eoi() into a helper
  x86/apic: Nuke ack_APIC_irq()
  x86/apic: Remove pointless arguments from [native_]eoi_write()
  x86/apic/noop: Tidy up the code
  x86/apic: Remove pointless NULL initializations
  x86/apic: Sanitize APIC ID range validation
  x86/apic: Prepare x2APIC for using apic::max_apic_id
  x86/apic: Simplify X2APIC ID validation
  x86/apic: Add max_apic_id member
  x86/apic: Wrap APIC ID validation into an inline
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'x86_microcode_for_v6.6_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2023-08-28T22:55:20+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-08-28T22:55:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=42a7f6e3ffe06308c1ec43a7dac39a27de101574'/>
<id>42a7f6e3ffe06308c1ec43a7dac39a27de101574</id>
<content type='text'>
Pull x86 microcode loading updates from Borislav Petkov:
 "The first, cleanup part of the microcode loader reorg tglx has been
  working on. The other part wasn't fully ready in time so it will
  follow on later.

  This part makes the loader core code as it is practically enabled on
  pretty much every baremetal machine so there's no need to have the
  Kconfig items.

  In addition, there are cleanups which prepare for future feature
  enablement"

* tag 'x86_microcode_for_v6.6_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/microcode: Remove remaining references to CONFIG_MICROCODE_AMD
  x86/microcode/intel: Remove pointless mutex
  x86/microcode/intel: Remove debug code
  x86/microcode: Move core specific defines to local header
  x86/microcode/intel: Rename get_datasize() since its used externally
  x86/microcode: Make reload_early_microcode() static
  x86/microcode: Include vendor headers into microcode.h
  x86/microcode/intel: Move microcode functions out of cpu/intel.c
  x86/microcode: Hide the config knob
  x86/mm: Remove unused microcode.h include
  x86/microcode: Remove microcode_mutex
  x86/microcode/AMD: Rip out static buffers
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull x86 microcode loading updates from Borislav Petkov:
 "The first, cleanup part of the microcode loader reorg tglx has been
  working on. The other part wasn't fully ready in time so it will
  follow on later.

  This part makes the loader core code as it is practically enabled on
  pretty much every baremetal machine so there's no need to have the
  Kconfig items.

  In addition, there are cleanups which prepare for future feature
  enablement"

* tag 'x86_microcode_for_v6.6_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/microcode: Remove remaining references to CONFIG_MICROCODE_AMD
  x86/microcode/intel: Remove pointless mutex
  x86/microcode/intel: Remove debug code
  x86/microcode: Move core specific defines to local header
  x86/microcode/intel: Rename get_datasize() since its used externally
  x86/microcode: Make reload_early_microcode() static
  x86/microcode: Include vendor headers into microcode.h
  x86/microcode/intel: Move microcode functions out of cpu/intel.c
  x86/microcode: Hide the config knob
  x86/mm: Remove unused microcode.h include
  x86/microcode: Remove microcode_mutex
  x86/microcode/AMD: Rip out static buffers
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'smp-core-2023-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2023-08-28T22:04:43+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-08-28T22:04:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=6f49693a6c85e7156d8fde589d9795a01c33c51a'/>
<id>6f49693a6c85e7156d8fde589d9795a01c33c51a</id>
<content type='text'>
Pull CPU hotplug updates from Thomas Gleixner:
 "Updates for the CPU hotplug core:

   - Support partial SMT enablement.

     So far the sysfs SMT control only allows to toggle between SMT on
     and off. That's sufficient for x86 which usually has at max two
     threads except for the Xeon PHI platform which has four threads per
     core

     Though PowerPC has up to 16 threads per core and so far it's only
     possible to control the number of enabled threads per core via a
     command line option. There is some way to control this at runtime,
     but that lacks enforcement and the usability is awkward

     This update expands the sysfs interface and the core infrastructure
     to accept numerical values so PowerPC can build SMT runtime control
     for partial SMT enablement on top

     The core support has also been provided to the PowerPC maintainers
     who added the PowerPC related changes on top

   - Minor cleanups and documentation updates"

* tag 'smp-core-2023-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Documentation: core-api/cpuhotplug: Fix state names
  cpu/hotplug: Remove unused function declaration cpu_set_state_online()
  cpu/SMT: Fix cpu_smt_possible() comment
  cpu/SMT: Allow enabling partial SMT states via sysfs
  cpu/SMT: Create topology_smt_thread_allowed()
  cpu/SMT: Remove topology_smt_supported()
  cpu/SMT: Store the current/max number of threads
  cpu/SMT: Move smt/control simple exit cases earlier
  cpu/SMT: Move SMT prototypes into cpu_smt.h
  cpu/hotplug: Remove dependancy against cpu_primary_thread_mask
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull CPU hotplug updates from Thomas Gleixner:
 "Updates for the CPU hotplug core:

   - Support partial SMT enablement.

     So far the sysfs SMT control only allows to toggle between SMT on
     and off. That's sufficient for x86 which usually has at max two
     threads except for the Xeon PHI platform which has four threads per
     core

     Though PowerPC has up to 16 threads per core and so far it's only
     possible to control the number of enabled threads per core via a
     command line option. There is some way to control this at runtime,
     but that lacks enforcement and the usability is awkward

     This update expands the sysfs interface and the core infrastructure
     to accept numerical values so PowerPC can build SMT runtime control
     for partial SMT enablement on top

     The core support has also been provided to the PowerPC maintainers
     who added the PowerPC related changes on top

   - Minor cleanups and documentation updates"

* tag 'smp-core-2023-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Documentation: core-api/cpuhotplug: Fix state names
  cpu/hotplug: Remove unused function declaration cpu_set_state_online()
  cpu/SMT: Fix cpu_smt_possible() comment
  cpu/SMT: Allow enabling partial SMT states via sysfs
  cpu/SMT: Create topology_smt_thread_allowed()
  cpu/SMT: Remove topology_smt_supported()
  cpu/SMT: Store the current/max number of threads
  cpu/SMT: Move smt/control simple exit cases earlier
  cpu/SMT: Move SMT prototypes into cpu_smt.h
  cpu/hotplug: Remove dependancy against cpu_primary_thread_mask
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/ibt: Convert IBT selftest to asm</title>
<updated>2023-08-17T15:07:09+00:00</updated>
<author>
<name>Josh Poimboeuf</name>
<email>jpoimboe@kernel.org</email>
</author>
<published>2023-04-08T00:16:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c6cfcbd8ca43766851a8c952e3b570727147020f'/>
<id>c6cfcbd8ca43766851a8c952e3b570727147020f</id>
<content type='text'>
The following warning is reported when frame pointers and kernel IBT are
enabled:

  vmlinux.o: warning: objtool: ibt_selftest+0x11: sibling call from callable instruction with modified stack frame

The problem is that objtool interprets the indirect branch in
ibt_selftest() as a sibling call, and GCC inserts a (partial) frame
pointer prologue before it:

  0000 000000000003f550 &lt;ibt_selftest&gt;:
  0000    3f550:	f3 0f 1e fa          	endbr64
  0004    3f554:	e8 00 00 00 00       	call   3f559 &lt;ibt_selftest+0x9&gt;	3f555: R_X86_64_PLT32	__fentry__-0x4
  0009    3f559:	55                   	push   %rbp
  000a    3f55a:	48 8d 05 02 00 00 00 	lea    0x2(%rip),%rax        # 3f563 &lt;ibt_selftest_ip&gt;
  0011    3f561:	ff e0                	jmp    *%rax

Note the inline asm is missing ASM_CALL_CONSTRAINT, so the 'push %rbp'
happens before the indirect branch and the 'mov %rsp, %rbp' happens
afterwards.

Simplify the generated code and make it easier to understand for both
tools and humans by moving the selftest to proper asm.

Signed-off-by: Josh Poimboeuf &lt;jpoimboe@kernel.org&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/99a7e16b97bda97bf0a04aa141d6241cd8a839a2.1680912949.git.jpoimboe@kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The following warning is reported when frame pointers and kernel IBT are
enabled:

  vmlinux.o: warning: objtool: ibt_selftest+0x11: sibling call from callable instruction with modified stack frame

The problem is that objtool interprets the indirect branch in
ibt_selftest() as a sibling call, and GCC inserts a (partial) frame
pointer prologue before it:

  0000 000000000003f550 &lt;ibt_selftest&gt;:
  0000    3f550:	f3 0f 1e fa          	endbr64
  0004    3f554:	e8 00 00 00 00       	call   3f559 &lt;ibt_selftest+0x9&gt;	3f555: R_X86_64_PLT32	__fentry__-0x4
  0009    3f559:	55                   	push   %rbp
  000a    3f55a:	48 8d 05 02 00 00 00 	lea    0x2(%rip),%rax        # 3f563 &lt;ibt_selftest_ip&gt;
  0011    3f561:	ff e0                	jmp    *%rax

Note the inline asm is missing ASM_CALL_CONSTRAINT, so the 'push %rbp'
happens before the indirect branch and the 'mov %rsp, %rbp' happens
afterwards.

Simplify the generated code and make it easier to understand for both
tools and humans by moving the selftest to proper asm.

Signed-off-by: Josh Poimboeuf &lt;jpoimboe@kernel.org&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/99a7e16b97bda97bf0a04aa141d6241cd8a839a2.1680912949.git.jpoimboe@kernel.org
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/microcode: Include vendor headers into microcode.h</title>
<updated>2023-08-13T16:42:55+00:00</updated>
<author>
<name>Ashok Raj</name>
<email>ashok.raj@intel.com</email>
</author>
<published>2023-08-12T19:58:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=82ad097b02b6ab7985375b925efd06ac042caf1d'/>
<id>82ad097b02b6ab7985375b925efd06ac042caf1d</id>
<content type='text'>
Currently vendor specific headers are included explicitly when used in
common code. Instead, include the vendor specific headers in
microcode.h, and include that in all usages.

No functional change.

Suggested-by: Boris Petkov &lt;bp@alien8.de&gt;
Signed-off-by: Ashok Raj &lt;ashok.raj@intel.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Link: https://lore.kernel.org/r/20230812195727.776541545@linutronix.de
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently vendor specific headers are included explicitly when used in
common code. Instead, include the vendor specific headers in
microcode.h, and include that in all usages.

No functional change.

Suggested-by: Boris Petkov &lt;bp@alien8.de&gt;
Signed-off-by: Ashok Raj &lt;ashok.raj@intel.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Link: https://lore.kernel.org/r/20230812195727.776541545@linutronix.de
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/cpu: Make identify_boot_cpu() static</title>
<updated>2023-08-09T18:58:15+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2023-08-08T22:03:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3ba3fdfe2c3f28b9976f0c07eb7736080cb7d4a9'/>
<id>3ba3fdfe2c3f28b9976f0c07eb7736080cb7d4a9</id>
<content type='text'>
It's not longer used outside the source file.

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Acked-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Tested-by: Michael Kelley &lt;mikelley@microsoft.com&gt;
Tested-by: Sohil Mehta &lt;sohil.mehta@intel.com&gt;
Tested-by: Juergen Gross &lt;jgross@suse.com&gt; # Xen PV (dom0 and unpriv. guest)
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
It's not longer used outside the source file.

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Acked-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Tested-by: Michael Kelley &lt;mikelley@microsoft.com&gt;
Tested-by: Sohil Mehta &lt;sohil.mehta@intel.com&gt;
Tested-by: Juergen Gross &lt;jgross@suse.com&gt; # Xen PV (dom0 and unpriv. guest)
</pre>
</div>
</content>
</entry>
</feed>
