linux-stable.git/arch/x86/kernel/cpu/proc.c, branch linux-rolling-stable

cpufreq: Allow arch_freq_get_on_cpu to return an error

2025-02-17T18:09:20+00:00

Allow arch_freq_get_on_cpu to return an error for cases when retrieving
current CPU frequency is not possible, whether that being due to lack of
required arch support or due to other circumstances when the current
frequency cannot be determined at given point of time.

Signed-off-by: Beata Michalska 
Reviewed-by: Prasanna Kumar T S M 
Acked-by: Viresh Kumar 
Acked-by: Rafael J. Wysocki 
Link: https://lore.kernel.org/r/20250131162439.3843071-2-beata.michalska@arm.com
Signed-off-by: Catalin Marinas

x86/cpu: Use str_yes_no() helper in show_cpuinfo_misc()

2024-10-26T13:37:15+00:00

Remove hard-coded strings by using the str_yes_no() helper function.

Signed-off-by: Thorsten Blum 
Signed-off-by: Borislav Petkov (AMD) 
Link: https://lore.kernel.org/r/20241026110808.78074-1-thorsten.blum@linux.dev

x86/cpu: Move cpu_core_id into topology info

2023-10-10T12:38:17+00:00

Rename it to core_id and stick it to the other ID fields.

No functional change.

Signed-off-by: Thomas Gleixner 
Tested-by: Juergen Gross 
Tested-by: Sohil Mehta 
Tested-by: Michael Kelley 
Tested-by: Peter Zijlstra (Intel) 
Tested-by: Zhang Rui 
Acked-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/r/20230814085112.566519388@linutronix.de

x86/cpu: Move phys_proc_id into topology info

2023-10-10T12:38:17+00:00

Rename it to pkg_id which is the terminology used in the kernel.

No functional change.

Signed-off-by: Thomas Gleixner 
Tested-by: Juergen Gross 
Tested-by: Sohil Mehta 
Tested-by: Michael Kelley 
Tested-by: Peter Zijlstra (Intel) 
Tested-by: Zhang Rui 
Acked-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/r/20230814085112.329006989@linutronix.de

x86/cpu: Encapsulate topology information in cpuinfo_x86

2023-10-10T12:38:17+00:00

The topology related information is randomly scattered across cpuinfo_x86.

Create a new structure cpuinfo_topo and move in a first step initial_apicid
and apicid into it.

Aside of being better readable this is in preparation for replacing the
horribly fragile CPU topology evaluation code further down the road.

Consolidate APIC ID fields to u32 as that represents the hardware type.

No functional change.

Signed-off-by: Thomas Gleixner 
Tested-by: Juergen Gross 
Tested-by: Sohil Mehta 
Tested-by: Michael Kelley 
Tested-by: Peter Zijlstra (Intel) 
Tested-by: Zhang Rui 
Acked-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/r/20230814085112.269787744@linutronix.de

x86: Expose thread features in /proc/$PID/status

2023-08-02T22:01:51+00:00

Applications and loaders can have logic to decide whether to enable
shadow stack. They usually don't report whether shadow stack has been
enabled or not, so there is no way to verify whether an application
actually is protected by shadow stack.

Add two lines in /proc/$PID/status to report enabled and locked features.

Since, this involves referring to arch specific defines in asm/prctl.h,
implement an arch breakout to emit the feature lines.

[Switched to CET, added to commit log]

Co-developed-by: Kirill A. Shutemov 
Signed-off-by: Kirill A. Shutemov 
Signed-off-by: Rick Edgecombe 
Signed-off-by: Dave Hansen 
Reviewed-by: Borislav Petkov (AMD) 
Reviewed-by: Kees Cook 
Acked-by: Mike Rapoport (IBM) 
Tested-by: Pengfei Xu 
Tested-by: John Allen 
Tested-by: Kees Cook 
Link: https://lore.kernel.org/all/20230613001108.3040476-37-rick.p.edgecombe%40intel.com

x86/aperfmperf: Integrate the fallback code from show_cpuinfo()

2022-04-27T18:22:20+00:00

Due to the avoidance of IPIs to idle CPUs arch_freq_get_on_cpu() can return
0 when the last sample was too long ago.

show_cpuinfo() has a fallback to cpufreq_quick_get() and if that fails to
return cpu_khz, but the readout code for the per CPU scaling frequency in
sysfs does not.

Move that fallback into arch_freq_get_on_cpu() so the behaviour is the same
when reading /proc/cpuinfo and /sys/..../cur_scaling_freq.

Suggested-by: "Rafael J. Wysocki" 
Signed-off-by: Thomas Gleixner 
Tested-by: Doug Smythies 
Link: https://lore.kernel.org/r/87pml5180p.ffs@tglx

x86/aperfmperf: Replace arch_freq_get_on_cpu()

2022-04-27T18:22:19+00:00

Reading the current CPU frequency from /sys/..../scaling_cur_freq involves
in the worst case two IPIs due to the ad hoc sampling.

The frequency invariance infrastructure provides the APERF/MPERF samples
already. Utilize them and consolidate this with the /proc/cpuinfo readout.

The sample is considered valid for 20ms. So for idle or isolated NOHZ full
CPUs the function returns 0, which is matching the previous behaviour.

The resulting text size vs. the original APERF/MPERF plus the separate
frequency invariance code:

  text:		2411	->   723
  init.text:	   0	->   767

Signed-off-by: Thomas Gleixner 
Tested-by: Eric Dumazet 
Reviewed-by: Rafael J. Wysocki 
Acked-by: Peter Zijlstra (Intel) 
Acked-by: Paul E. McKenney 
Link: https://lore.kernel.org/r/20220415161206.934040006@linutronix.de

x86/cpu: Print VMX flags in /proc/cpuinfo using VMX_FEATURES_*

2020-01-13T17:36:02+00:00

Add support for generating VMX feature names in capflags.c and use the
resulting x86_vmx_flags to print the VMX flags in /proc/cpuinfo.  Don't
print VMX flags if no bits are set in word 0, which holds Pin Controls.
Pin Control's INTR and NMI exiting are fundamental pillars of VMX, if
they are not supported then the CPU is broken, it does not actually
support VMX, or the kernel wasn't built with support for the target CPU.

Print the features in a dedicated "vmx flags" line to avoid polluting
the common "flags" and to avoid having to prefix all flags with "vmx_",
which results in horrendously long names.

Keep synthetic VMX flags in cpufeatures to preserve /proc/cpuinfo's ABI
for those flags.  This means that "flags" and "vmx flags" will have
duplicate entries for tpr_shadow (virtual_tpr), vnmi, ept, flexpriority,
vpid and ept_ad, but caps the pollution of "flags" at those six VMX
features.  The vendor-specific code that populates the synthetic flags
will be consolidated in a future patch to further minimize the lasting
damage.

Signed-off-by: Sean Christopherson 
Signed-off-by: Borislav Petkov 
Link: https://lkml.kernel.org/r/20191221044513.21680-12-sean.j.christopherson@intel.com

x86: Convert some slow-path static_cpu_has() callers to boot_cpu_has()

2019-04-08T10:13:34+00:00

Using static_cpu_has() is pointless on those paths, convert them to the
boot_cpu_has() variant.

No functional changes.

Reported-by: Nadav Amit 
Signed-off-by: Borislav Petkov 
Reviewed-by: Rik van Riel 
Reviewed-by: Juergen Gross  # for paravirt
Cc: Aubrey Li 
Cc: Dave Hansen 
Cc: Dominik Brodowski 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Jann Horn 
Cc: Joerg Roedel 
Cc: "Kirill A. Shutemov" 
Cc: Konrad Rzeszutek Wilk 
Cc: Thomas Lendacky 
Cc: linux-edac@vger.kernel.org
Cc: Masami Hiramatsu 
Cc: Peter Zijlstra 
Cc: "Rafael J. Wysocki" 
Cc: Sebastian Andrzej Siewior 
Cc: Thomas Gleixner 
Cc: Tony Luck 
Cc: virtualization@lists.linux-foundation.org
Cc: x86@kernel.org
Link: https://lkml.kernel.org/r/20190330112022.28888-3-bp@alien8.de