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Simplify one of the last few Intel x86_model checks in arch/x86 by
substituting it with a VFM one.
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20250219184133.816753-5-sohil.mehta@intel.com
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The Family model check to read the processor flag MSR is misleading and
potentially incorrect. It doesn't consider Family while comparing the
model number. The original check did have a Family number but it got
lost/moved during refactoring.
intel_collect_cpu_info() is called through multiple paths such as early
initialization, CPU hotplug as well as IFS image load. Some of these
flows would be error prone due to the ambiguous check.
Correct the processor flag scan check to use a Family number and update
it to a VFM based one to make it more readable.
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20250219184133.816753-4-sohil.mehta@intel.com
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The alignment preference for 32-bit MOVSL based bulk memory move has
been 8-byte for a long time. However this preference is only set for
Family 6 and 15 processors.
Use the same preference for upcoming Family numbers 18 and 19. Also, use
a simpler VFM based check instead of switching based on Family numbers.
Refresh the comment to reflect the new check.
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250219184133.816753-3-sohil.mehta@intel.com
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APIC detection is currently limited to a few specific Families and will
not match the upcoming Families >=18.
Extend the check to include all Families 6 or greater. Also convert it
to a VFM check to make it simpler.
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20250219184133.816753-2-sohil.mehta@intel.com
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Use u32 instead of uint32_t in hypervisor_cpuid_base().
Yes, uint32_t is used in Xen code et al, but this is a core x86
architecture header and we should standardize on the type that
is being used overwhelmingly in related x86 architecture code.
The two types are the same so there should be no build warnings.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: "Ahmed S. Darwish" <darwi@linutronix.de>
Cc: x86-cpuid@lists.linux.dev
Link: https://lore.kernel.org/r/20250317221824.3738853-6-mingo@kernel.org
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Convert all uses of 'unsigned int' to 'u32' in <asm/cpuid/api.h>.
This is how a lot of the call sites are doing it, and the two
types are equivalent in the C sense - but 'u32' better expresses
that these are expressions of an immutable hardware ABI.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Xin Li (Intel) <xin@zytor.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: "Ahmed S. Darwish" <darwi@linutronix.de>
Cc: x86-cpuid@lists.linux.dev
Link: https://lore.kernel.org/r/20250317221824.3738853-5-mingo@kernel.org
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- Include <asm/cpuid/types.h> first, as is customary. This also has
the side effect of build-testing the header dependency assumptions
in the types header.
- No newline necessary after the SPDX line
- Newline necessary after inline function definitions
- Rename native_cpuid_reg() to NATIVE_CPUID_REG(): it's a CPP macro,
whose name we capitalize in such cases.
- Prettify the CONFIG_PARAVIRT_XXL inclusion block a bit
- Standardize register references in comments to EAX/EBX/ECX/etc.,
from the hodgepodge of references.
- s/cpus/CPUs because why add noise to common acronyms?
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: "Ahmed S. Darwish" <darwi@linutronix.de>
Cc: x86-cpuid@lists.linux.dev
Link: https://lore.kernel.org/r/20250317221824.3738853-4-mingo@kernel.org
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- We have 0x0d, 0x9 and 0x1d as literals for the CPUID_LEAF definitions,
pick a single, consistent style of 0xZZ literals.
- Likewise, harmonize the style of the 'struct cpuid_regs' list of
registers with that of 'enum cpuid_regs_idx'. Because while computers
don't care about unnecessary visual noise, humans do.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: "Ahmed S. Darwish" <darwi@linutronix.de>
Cc: x86-cpuid@lists.linux.dev
Link: https://lore.kernel.org/r/20250317221824.3738853-3-mingo@kernel.org
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In preparation for future commits where CPUID headers will be expanded,
refactor the CPUID header <asm/cpuid.h> into:
asm/cpuid/
├── api.h
└── types.h
Move the CPUID data structures into <asm/cpuid/types.h> and the access
APIs into <asm/cpuid/api.h>. Let <asm/cpuid.h> be just an include of
<asm/cpuid/api.h> so that existing call sites do not break.
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: "Ahmed S. Darwish" <darwi@linutronix.de>
Cc: x86-cpuid@lists.linux.dev
Link: https://lore.kernel.org/r/20250317221824.3738853-2-mingo@kernel.org
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Add a CONFIG_X86_FRED comment, since this conditional is nested.
Suggested-by: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250314151220.862768-8-brgerst@gmail.com
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No functional change.
Suggested-by: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250314151220.862768-7-brgerst@gmail.com
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Move sys_ni_syscall() to kernel/process.c, and remove the now empty
entry/common.c
No functional changes.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250314151220.862768-6-brgerst@gmail.com
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Since commit:
2e958a8a510d ("x86/entry/x32: Rename __x32_compat_sys_* to __x64_compat_sys_*")
the ABI prefix for x32 syscalls is the same as native 64-bit
syscalls. Move the x32 syscall table to syscall_64.c
No functional changes.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250314151220.862768-5-brgerst@gmail.com
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Move the 64-bit syscall dispatch code to syscall_64.c.
No functional changes.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250314151220.862768-4-brgerst@gmail.com
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Move the 32-bit syscall dispatch code to syscall_32.c.
No functional changes.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250314151220.862768-3-brgerst@gmail.com
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Move the upcall handler to Xen-specific files.
No functional changes.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250314151220.862768-2-brgerst@gmail.com
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Some of the ACP drivers will poll registers through SMN using
read_poll_timeout() which requires returning the result of the register read
as the argument.
Add a helper to do just that.
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250217231747.1656228-2-superm1@kernel.org
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There are certain registers on AMD Zen systems that can only be accessed
through SMN.
Introduce a new interface that provides debugfs files for accessing SMN. As
this introduces the capability for userspace to manipulate the hardware in
unpredictable ways, taint the kernel when writing.
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250130-wip-x86-amd-nb-cleanup-v4-3-b5cc997e471b@amd.com
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Offsets 0x60 and 0x64 are used internally by kernel drivers that call
the amd_smn_read() and amd_smn_write() functions. If userspace accesses
the regions at the same time as the kernel it may cause malfunctions in
drivers using the offsets.
Add these offsets to the exclusions so that the kernel is tainted if a
non locked down userspace tries to access them.
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250130-wip-x86-amd-nb-cleanup-v4-2-b5cc997e471b@amd.com
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The HSMP interface is just an SMN interface with different offsets.
Define an HSMP wrapper in the SMN code and have the HSMP platform driver
use that rather than a local solution.
Also, remove the "root" member from AMD_NB, since there are no more
users of it.
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Carlos Bilbao <carlos.bilbao@kernel.org>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20250130-wip-x86-amd-nb-cleanup-v4-1-b5cc997e471b@amd.com
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Remove hard-coded strings by using the str_enabled_disabled() helper
function.
Suggested-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/all/20250117144900.171684-2-thorsten.blum%40linux.dev
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ia32_emulation_override_cmdline() is an early_param() arg and these
are only needed at boot time. In fact, all other early_param() functions
in arch/x86 seem to have '__init' annotation and
ia32_emulation_override_cmdline() is the only exception.
Fixes: a11e097504ac ("x86: Make IA32_EMULATION boot time configurable")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Link: https://lore.kernel.org/all/20241210151650.1746022-1-vkuznets%40redhat.com
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Currently, the cpuid_deps[] table is only exercised when a particular
feature is explicitly disabled and clear_cpu_cap() is called. However,
some of these listed dependencies might already be missing during boot.
These types of errors shouldn't generally happen in production
environments, but they could sometimes sneak through, especially when
VMs and Kconfigs are in the mix. Also, the kernel might introduce
artificial dependencies between unrelated features, such as making LAM
depend on LASS.
Unexpected failures can occur when the kernel tries to use such
features. Add a simple boot-time scan of the cpuid_deps[] table to
detect the missing dependencies. One option is to disable all of such
features during boot, but that may cause regressions in existing
systems. For now, just warn about the missing dependencies to create
awareness.
As a trade-off between spamming the kernel log and keeping track of all
the features that have been warned about, only warn about the first
missing dependency. Any subsequent unmet dependency will only be logged
after the first one has been resolved.
Features are typically represented through unsigned integers within the
kernel, though some of them have user-friendly names if they are exposed
via /proc/cpuinfo.
Show the friendlier name if available, otherwise display the
X86_FEATURE_* numerals to make it easier to identify the feature.
Suggested-by: Tony Luck <tony.luck@intel.com>
Suggested-by: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250313201608.3304135-1-sohil.mehta@intel.com
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The affected CPU table (cpu_vuln_blacklist) marks Alderlake and Raptorlake
P-only parts affected by RFDS. This is not true because only E-cores are
affected by RFDS. With the current family/model matching it is not possible
to differentiate the unaffected parts, as the affected and unaffected
hybrid variants have the same model number.
Add a cpu-type match as well for such parts so as to exclude P-only parts
being marked as affected.
Note, family/model and cpu-type enumeration could be inaccurate in
virtualized environments. In a guest affected status is decided by RFDS_NO
and RFDS_CLEAR bits exposed by VMMs.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20250311-add-cpu-type-v8-5-e8514dcaaff2@linux.intel.com
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Non-hybrid CPU variants that share the same Family/Model could be
differentiated by their cpu-type. x86_match_cpu() currently does not use
cpu-type for CPU matching.
Dave Hansen suggested to use below conditions to match CPU-type:
1. If CPU_TYPE_ANY (the wildcard), then matched
2. If hybrid, then matched
3. If !hybrid, look at the boot CPU and compare the cpu-type to determine
if it is a match.
This special case for hybrid systems allows more compact vulnerability
list. Imagine that "Haswell" CPUs might or might not be hybrid and that
only Atom cores are vulnerable to Meltdown. That means there are three
possibilities:
1. P-core only
2. Atom only
3. Atom + P-core (aka. hybrid)
One might be tempted to code up the vulnerability list like this:
MATCH( HASWELL, X86_FEATURE_HYBRID, MELTDOWN)
MATCH_TYPE(HASWELL, ATOM, MELTDOWN)
Logically, this matches #2 and #3. But that's a little silly. You would
only ask for the "ATOM" match in cases where there *WERE* hybrid cores in
play. You shouldn't have to _also_ ask for hybrid cores explicitly.
In short, assume that processors that enumerate Hybrid==1 have a
vulnerable core type.
Update x86_match_cpu() to also match cpu-type. Also treat hybrid systems as
special, and match them to any cpu-type.
Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20250311-add-cpu-type-v8-4-e8514dcaaff2@linux.intel.com
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In addition to matching vendor/family/model/feature, for hybrid variants it is
required to also match cpu-type. For example, some CPU vulnerabilities like
RFDS only affect a specific cpu-type.
To be able to also match CPUs based on their type, add a new field "type" to
struct x86_cpu_id which is used by the CPU-matching tables. Introduce
X86_CPU_TYPE_ANY for the cases that don't care about the cpu-type.
[ bp: Massage commit message. ]
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20250311-add-cpu-type-v8-3-e8514dcaaff2@linux.intel.com
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To add cpu-type to the existing CPU matching infrastructure, the base macro
X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE need to append _CPU_TYPE. This
makes an already long name longer, and somewhat incomprehensible.
To avoid this, rename the base macro to X86_MATCH_CPU. The macro name
doesn't need to explicitly tell everything that it matches. The arguments
to the macro already hint at that.
For consistency, use this base macro to define X86_MATCH_VFM and friends.
Remove unused X86_MATCH_VENDOR_FAM_MODEL_FEATURE while at it.
[ bp: Massage commit message. ]
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20250311-add-cpu-type-v8-2-e8514dcaaff2@linux.intel.com
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The comments needs to reflect an implementation change.
No functional change.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250311-add-cpu-type-v8-1-e8514dcaaff2@linux.intel.com
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<asm/cpufeaturemasks.h>
Generate the {REQUIRED|DISABLED}_MASK_BIT_SET macros in the newly added AWK
script that generates <asm/cpufeaturemasks.h>.
Suggested-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Brian Gerst <brgerst@gmail.com>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250228082338.73859-6-xin@zytor.com
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The functionalities of {disabled,required}-features.h have been replaced with
the auto-generated generated/<asm/cpufeaturemasks.h> header.
Thus they are no longer needed and can be removed.
None of the macros defined in {disabled,required}-features.h is used in tools,
delete them too.
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250305184725.3341760-4-xin@zytor.com
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config
Introduce an AWK script to auto-generate the <asm/cpufeaturemasks.h> header
with required and disabled feature masks based on <asm/cpufeatures.h>
and the current build config.
Thus for any CPU feature with a build config, e.g., X86_FRED, simply add:
config X86_DISABLED_FEATURE_FRED
def_bool y
depends on !X86_FRED
to arch/x86/Kconfig.cpufeatures, instead of adding a conditional CPU
feature disable flag, e.g., DISABLE_FRED.
Lastly, the generated required and disabled feature masks will be added to
their corresponding feature masks for this particular compile-time
configuration.
[ Xin: build integration improvements ]
[ mingo: Improved changelog and comments ]
Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250305184725.3341760-3-xin@zytor.com
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Required and disabled feature masks completely rely on build configs,
i.e., once a build config is fixed, so are the feature masks.
To prepare for auto-generating the <asm/cpufeaturemasks.h> header
with required and disabled feature masks based on a build config,
add feature Kconfig items:
- X86_REQUIRED_FEATURE_x
- X86_DISABLED_FEATURE_x
each of which may be set to "y" if and only if its preconditions from
current build config are met.
Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250228082338.73859-3-xin@zytor.com
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The current calculation of the 'next' virtual address in the
page table initialization functions in arch/x86/mm/ident_map.c
doesn't protect against wrapping to zero.
This is a theoretical issue that cannot happen currently,
the problematic case is possible only if the user sets a
high enough x86_mapping_info::offset value - which no
current code in the upstream kernel does.
( The wrapping to zero only occurs if the top PGD entry is accessed.
There are no such users upstream. Only hibernate_64.c uses
x86_mapping_info::offset, and it operates on the direct mapping
range, which is not the top PGD entry. )
Should such an overflow happen, it can result in page table
corruption and a hang.
To future-proof this code, replace the manual 'next' calculation
with p?d_addr_end() which handles wrapping correctly.
[ Backporter's note: there's no need to backport this patch. ]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20241016111458.846228-2-kirill.shutemov@linux.intel.com
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kernel_ident_mapping_init()
The init_transition_pgtable() functions maps the page with
asm_acpi_mp_play_dead() into an identity mapping.
Replace open-coded manual page table initialization with
kernel_ident_mapping_init() to avoid code duplication.
Use x86_mapping_info::offset to get the page mapped at the
correct location.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20241016111458.846228-3-kirill.shutemov@linux.intel.com
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When executing the INVLPGB instruction on a bare-metal host or hypervisor, if
the ASID valid bit is not set, the instruction will flush the TLB entries that
match the specified criteria for any ASID, not just the those of the host. If
virtual machines are running on the system, this may result in inadvertent
flushes of guest TLB entries.
When executing the INVLPGB instruction in a guest and the INVLPGB instruction is
not intercepted by the hypervisor, the hardware will replace the requested ASID
with the guest ASID and set the ASID valid bit before doing the broadcast
invalidation. Thus a guest is only able to flush its own TLB entries.
So to limit the host TLB flushing reach, always set the ASID valid bit using an
ASID value of 0 (which represents the host/hypervisor). This will will result in
the desired effect in both host and guest.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250304120449.GHZ8bsYYyEBOKQIxBm@fat_crate.local
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With AMD TCE (translation cache extensions) only the intermediate mappings
that cover the address range zapped by INVLPG / INVLPGB get invalidated,
rather than all intermediate mappings getting zapped at every TLB invalidation.
This can help reduce the TLB miss rate, by keeping more intermediate mappings
in the cache.
From the AMD manual:
Translation Cache Extension (TCE) Bit. Bit 15, read/write. Setting this bit to
1 changes how the INVLPG, INVLPGB, and INVPCID instructions operate on TLB
entries. When this bit is 0, these instructions remove the target PTE from the
TLB as well as all upper-level table entries that are cached in the TLB,
whether or not they are associated with the target PTE. When this bit is set,
these instructions will remove the target PTE and only those upper-level
entries that lead to the target PTE in the page table hierarchy, leaving
unrelated upper-level entries intact.
[ bp: use cpu_has()... I know, it is a mess. ]
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250226030129.530345-13-riel@surriel.com
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There is not enough room in the 12-bit ASID address space to hand out
broadcast ASIDs to every process. Only hand out broadcast ASIDs to processes
when they are observed to be simultaneously running on 4 or more CPUs.
This also allows single threaded process to continue using the cheaper, local
TLB invalidation instructions like INVLPGB.
Due to the structure of flush_tlb_mm_range(), the INVLPGB flushing is done in
a generically named broadcast_tlb_flush() function which can later also be
used for Intel RAR.
Combined with the removal of unnecessary lru_add_drain calls() (see
https://lore.kernel.org/r/20241219153253.3da9e8aa@fangorn) this results in
a nice performance boost for the will-it-scale tlb_flush2_threads test on an
AMD Milan system with 36 cores:
- vanilla kernel: 527k loops/second
- lru_add_drain removal: 731k loops/second
- only INVLPGB: 527k loops/second
- lru_add_drain + INVLPGB: 1157k loops/second
Profiling with only the INVLPGB changes showed while TLB invalidation went
down from 40% of the total CPU time to only around 4% of CPU time, the
contention simply moved to the LRU lock.
Fixing both at the same time about doubles the number of iterations per second
from this case.
Comparing will-it-scale tlb_flush2_threads with several different numbers of
threads on a 72 CPU AMD Milan shows similar results. The number represents the
total number of loops per second across all the threads:
threads tip INVLPGB
1 315k 304k
2 423k 424k
4 644k 1032k
8 652k 1267k
16 737k 1368k
32 759k 1199k
64 636k 1094k
72 609k 993k
1 and 2 thread performance is similar with and without INVLPGB, because
INVLPGB is only used on processes using 4 or more CPUs simultaneously.
The number is the median across 5 runs.
Some numbers closer to real world performance can be found at Phoronix, thanks
to Michael:
https://www.phoronix.com/news/AMD-INVLPGB-Linux-Benefits
[ bp:
- Massage
- :%s/\<static_cpu_has\>/cpu_feature_enabled/cgi
- :%s/\<clear_asid_transition\>/mm_clear_asid_transition/cgi
- Fold in a 0day bot fix: https://lore.kernel.org/oe-kbuild-all/202503040000.GtiWUsBm-lkp@intel.com
]
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nadav Amit <nadav.amit@gmail.com>
Link: https://lore.kernel.org/r/20250226030129.530345-11-riel@surriel.com
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A global ASID is allocated for the lifetime of a process. Free the global ASID
at process exit time.
[ bp: Massage, create helpers, hide details inside them. ]
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250226030129.530345-10-riel@surriel.com
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Do context switch and TLB flush support for processes that use a global
ASID and PCID across all CPUs.
At both context switch time and TLB flush time, it needs to be checked whether
a task is switching to a global ASID, and, if so, reload the TLB with the new
ASID as appropriate.
In both code paths, the TLB flush is avoided if a global ASID is used, because
the global ASIDs are always kept up to date across CPUs, even when the
process is not running on a CPU.
[ bp:
- Massage
- :%s/\<static_cpu_has\>/cpu_feature_enabled/cgi
]
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250226030129.530345-9-riel@surriel.com
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Add functions to manage global ASID space. Multithreaded processes that are
simultaneously active on 4 or more CPUs can get a global ASID, resulting in the
same PCID being used for that process on every CPU.
This in turn will allow the kernel to use hardware-assisted TLB flushing
through AMD INVLPGB or Intel RAR for these processes.
[ bp:
- Extend use_global_asid() comment
- s/X86_BROADCAST_TLB_FLUSH/BROADCAST_TLB_FLUSH/g
- other touchups ]
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250226030129.530345-8-riel@surriel.com
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Page reclaim tracks only the CPU(s) where the TLB needs to be flushed, rather
than all the individual mappings that may be getting invalidated.
Use broadcast TLB flushing when that is available.
[ bp: Massage commit message. ]
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250226030129.530345-7-riel@surriel.com
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Use broadcast TLB invalidation for kernel addresses when available.
Remove the need to send IPIs for kernel TLB flushes.
[ bp: Integrate dhansen's comments additions, merge the
flush_tlb_all() change into this one too. ]
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250226030129.530345-5-riel@surriel.com
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Add helper functions and definitions needed to use broadcast TLB
invalidation on AMD CPUs.
[ bp:
- Cleanup commit message
- Improve and expand comments
- push the preemption guards inside the invlpgb* helpers
- merge improvements from dhansen
- add !CONFIG_BROADCAST_TLB_FLUSH function stubs because Clang
can't do DCE properly yet and looks at the inline asm and
complains about it getting a u64 argument on 32-bit code ]
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250226030129.530345-4-riel@surriel.com
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In addition, the CPU advertises the maximum number of pages that can be
shot down with one INVLPGB instruction in CPUID. Save that information
for later use.
[ bp: use cpu_has(), typos, massage. ]
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250226030129.530345-3-riel@surriel.com
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Reduce code duplication by consolidating the decision point for whether to do
individual invalidations or a full flush inside get_flush_tlb_info().
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Link: https://lore.kernel.org/r/20250226030129.530345-2-riel@surriel.com
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At least with CONFIG_PHYSICAL_START=0x100000, if there is < 4 MiB of
contiguous free memory available at this point, the kernel will crash
and burn because memblock_phys_alloc_range() returns 0 on failure,
which leads memblock_phys_free() to throw the first 4 MiB of physical
memory to the wolves.
At a minimum it should fail gracefully with a meaningful diagnostic,
but in fact everything seems to work fine without the weird reserve
allocation.
Signed-off-by: Philip Redkin <me@rarity.fan>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lore.kernel.org/r/94b3e98f-96a7-3560-1f76-349eb95ccf7f@rarity.fan
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The file arch/x86/um/asm/module.h is equivalent to the definition of
asm-generic. Thus this commit cleans up to use it.
Signed-off-by: Hajime Tazaki <thehajime@gmail.com>
Link: https://patch.msgid.link/2d70a0ed79ee0a0bef80ad4790063f4833dd9bed.1737348399.git.thehajime@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Doing this allows using registers as retrieved from an mcontext to be
pushed to a process using PTRACE_SETREGS.
It is not entirely clear to me why CSGSFS was masked. Doing so creates
issues when using the mcontext as process state in seccomp and simply
copying the register appears to work perfectly fine for ptrace.
Signed-off-by: Benjamin Berg <benjamin@sipsolutions.net>
Link: https://patch.msgid.link/20250224181827.647129-2-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Minimum version of binutils required to compile the kernel is 2.25.
This version correctly handles the "lock" prefix, so it is possible
to remove the semicolon, which was used to support ancient versions
of GNU as.
Due to the semicolon, the compiler considers "lock; insn" as two
separate instructions. Removing the semicolon makes asm length
calculations more accurate, consequently making scheduling and
inlining decisions of the compiler more accurate.
Removing the semicolon also enables assembler checks involving lock
prefix. Trying to assemble e.g. "lock andl %eax, %ebx" results in:
Error: expecting lockable instruction after `lock'
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://patch.msgid.link/20250228090058.2499163-1-ubizjak@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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