Linux remembers cpu_cachinfo::num_leaves per CPU, but x86 initializes all
CPUs from the same global "num_cache_leaves".
This is erroneous on systems such as Meteor Lake, where each CPU has a
distinct num_leaves value. Delete the global "num_cache_leaves" and
initialize num_leaves on each CPU.
init_cache_level() no longer needs to set num_leaves. Also, it never had to
set num_levels as it is unnecessary in x86. Keep checking for zero cache
leaves. Such condition indicates a bug.
[ bp: Cleanup. ]
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org # 6.3+
Link: https://lore.kernel.org/r/20241128002247.26726-3-ricardo.neri-calderon@linux.intel.com
The rework of possible CPUs management erroneously disabled SMP when the
IO/APIC is disabled either by the 'noapic' command line parameter or during
IO/APIC setup. SMP is possible without IO/APIC.
Remove the ioapic_is_disabled conditions from the relevant possible CPU
management code paths to restore the orgininal behaviour.
Fixes: 7c0edad364 ("x86/cpu/topology: Rework possible CPU management")
Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20241202145905.1482-1-ffmancera@riseup.net
Pull x86 fixes from Borislav Petkov:
- Add a terminating zero end-element to the array describing AMD CPUs
affected by erratum 1386 so that the matching loop actually
terminates instead of going off into the weeds
- Update the boot protocol documentation to mention the fact that the
preferred address to load the kernel to is considered in the
relocatable kernel case too
- Flush the memory buffer containing the microcode patch after applying
microcode on AMD Zen1 and Zen2, to avoid unnecessary slowdowns
- Make sure the PPIN CPU feature flag is cleared on all CPUs if PPIN
has been disabled
* tag 'x86_urgent_for_v6.13_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/CPU/AMD: Terminate the erratum_1386_microcode array
x86/Documentation: Update algo in init_size description of boot protocol
x86/microcode/AMD: Flush patch buffer mapping after application
x86/mm: Carve out INVLPG inline asm for use by others
x86/cpu: Fix PPIN initialization
When the size isn't a small constant, __access_ok() will call
valid_user_address() with the address after the last byte of the user
buffer.
It is valid for a buffer to end with the last valid user address so
valid_user_address() must allow accesses to the base of the guard page.
[ This introduces an off-by-one in the other direction for the plain
non-sized accesses, but since we have that guard region that is a
whole page, those checks "allowing" accesses to that guard region
don't really matter. The access will fault anyway, whether to the
guard page or if the address has been masked to all ones - Linus ]
Fixes: 86e6b1547b ("x86: fix user address masking non-canonical speculation issue")
Signed-off-by: David Laight <david.laight@aculab.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On systems that enumerate PPIN (protected processor inventory
number) using CPUID, but where the BIOS locked the MSR to
prevent access /proc/cpuinfo reports "intel_ppin" feature as
present on all logical CPUs except for CPU 0.
This happens because ppin_init() uses x86_match_cpu() to
determine whether PPIN is supported. When called on CPU 0
the test for locked PPIN MSR results in:
clear_cpu_cap(c, info->feature);
This clears the X86 FEATURE bit in boot_cpu_data. When other
CPUs are brought online the x86_match_cpu() fails, and the
PPIN FEATURE bit remains set for those other CPUs.
Fix by using setup_clear_cpu_cap() instead of clear_cpu_cap()
which force clears the FEATURE bit for all CPUS.
Reported-by: Adeel Ashad <adeel.arshad@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20241122234212.27451-1-tony.luck@intel.com
Pull misc x86 updates from Dave Hansen:
"As usual for this branch, these are super random: a compile fix for
some newish LLVM checks and making sure a Kconfig text reference to
'RSB' matches the normal definition:
- Rework some CPU setup code to keep LLVM happy on 32-bit
- Correct RSB terminology in Kconfig text"
* tag 'x86_misc_for_6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/cpu: Make sure flag_is_changeable_p() is always being used
x86/bugs: Correct RSB terminology in Kconfig
Pull sgx update from Dave Hansen:
- Use vmalloc_array() instead of vmalloc()
* tag 'x86_sgx_for_6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sgx: Use vmalloc_array() instead of vmalloc()
Pull x86 cleanups from Ingo Molnar:
- x86/boot: Remove unused function atou() (Dr. David Alan Gilbert)
- x86/cpu: Use str_yes_no() helper in show_cpuinfo_misc() (Thorsten
Blum)
- x86/platform: Switch back to struct platform_driver::remove() (Uwe
Kleine-König)
* tag 'x86-cleanups-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/boot: Remove unused function atou()
x86/cpu: Use str_yes_no() helper in show_cpuinfo_misc()
x86/platform: Switch back to struct platform_driver::remove()
Pull x86 splitlock updates from Ingo Molnar:
- Move Split and Bus lock code to a dedicated file (Ravi Bangoria)
- Add split/bus lock support for AMD (Ravi Bangoria)
* tag 'x86-splitlock-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/bus_lock: Add support for AMD
x86/split_lock: Move Split and Bus lock code to a dedicated file
Pull performance events updates from Ingo Molnar:
"Uprobes:
- Add BPF session support (Jiri Olsa)
- Switch to RCU Tasks Trace flavor for better performance (Andrii
Nakryiko)
- Massively increase uretprobe SMP scalability by SRCU-protecting
the uretprobe lifetime (Andrii Nakryiko)
- Kill xol_area->slot_count (Oleg Nesterov)
Core facilities:
- Implement targeted high-frequency profiling by adding the ability
for an event to "pause" or "resume" AUX area tracing (Adrian
Hunter)
VM profiling/sampling:
- Correct perf sampling with guest VMs (Colton Lewis)
New hardware support:
- x86/intel: Add PMU support for Intel ArrowLake-H CPUs (Dapeng Mi)
Misc fixes and enhancements:
- x86/intel/pt: Fix buffer full but size is 0 case (Adrian Hunter)
- x86/amd: Warn only on new bits set (Breno Leitao)
- x86/amd/uncore: Avoid a false positive warning about snprintf
truncation in amd_uncore_umc_ctx_init (Jean Delvare)
- uprobes: Re-order struct uprobe_task to save some space
(Christophe JAILLET)
- x86/rapl: Move the pmu allocation out of CPU hotplug (Kan Liang)
- x86/rapl: Clean up cpumask and hotplug (Kan Liang)
- uprobes: Deuglify xol_get_insn_slot/xol_free_insn_slot paths (Oleg
Nesterov)"
* tag 'perf-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits)
perf/core: Correct perf sampling with guest VMs
perf/x86: Refactor misc flag assignments
perf/powerpc: Use perf_arch_instruction_pointer()
perf/core: Hoist perf_instruction_pointer() and perf_misc_flags()
perf/arm: Drop unused functions
uprobes: Re-order struct uprobe_task to save some space
perf/x86/amd/uncore: Avoid a false positive warning about snprintf truncation in amd_uncore_umc_ctx_init
perf/x86/intel: Do not enable large PEBS for events with aux actions or aux sampling
perf/x86/intel/pt: Add support for pause / resume
perf/core: Add aux_pause, aux_resume, aux_start_paused
perf/x86/intel/pt: Fix buffer full but size is 0 case
uprobes: SRCU-protect uretprobe lifetime (with timeout)
uprobes: allow put_uprobe() from non-sleepable softirq context
perf/x86/rapl: Clean up cpumask and hotplug
perf/x86/rapl: Move the pmu allocation out of CPU hotplug
uprobe: Add support for session consumer
uprobe: Add data pointer to consumer handlers
perf/x86/amd: Warn only on new bits set
uprobes: fold xol_take_insn_slot() into xol_get_insn_slot()
uprobes: kill xol_area->slot_count
...
Pull x86 cpuid updates from Borislav Petkov:
- Add a feature flag which denotes AMD CPUs supporting workload
classification with the purpose of using such hints when making
scheduling decisions
- Determine the boost enumerator for each AMD core based on its type:
efficiency or performance, in the cppc driver
- Add the type of a CPU to the topology CPU descriptor with the goal of
supporting and making decisions based on the type of the respective
core
- Add a feature flag to denote AMD cores which have heterogeneous
topology and enable SD_ASYM_PACKING for those
- Check microcode revisions before disabling PCID on Intel
- Cleanups and fixlets
* tag 'x86_cpu_for_v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/cpu: Remove redundant CONFIG_NUMA guard around numa_add_cpu()
x86/cpu: Fix FAM5_QUARK_X1000 to use X86_MATCH_VFM()
x86/cpu: Fix formatting of cpuid_bits[] in scattered.c
x86/cpufeatures: Add X86_FEATURE_AMD_WORKLOAD_CLASS feature bit
x86/amd: Use heterogeneous core topology for identifying boost numerator
x86/cpu: Add CPU type to struct cpuinfo_topology
x86/cpu: Enable SD_ASYM_PACKING for PKG domain on AMD
x86/cpufeatures: Add X86_FEATURE_AMD_HETEROGENEOUS_CORES
x86/cpufeatures: Rename X86_FEATURE_FAST_CPPC to have AMD prefix
x86/mm: Don't disable PCID when INVLPG has been fixed by microcode
Pull x86 microcode loader update from Borislav Petkov:
- Remove the unconditional cache writeback and invalidation after
loading the microcode patch on Intel as this was addressing a
microcode bug for which there is a concrete microcode revision check
instead
* tag 'x86_microcode_for_v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/microcode/intel: Remove unnecessary cache writeback and invalidation
Pull x86 cache resource control updates from Borislav Petkov:
- Add support for 6-node sub-NUMA clustering on Intel
- Cleanup
* tag 'x86_cache_for_v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/resctrl: Support Sub-NUMA cluster mode SNC6
x86/resctrl: Slightly clean-up mbm_config_show()
Pull RAS updates from Borislav Petkov:
- Log and handle twp new AMD-specific MCA registers: SYND1 and SYND2
and report the Field Replaceable Unit text info reported through them
- Add support for handling variable-sized SMCA BERT records
- Add the capability for reporting vendor-specific RAS error info
without adding vendor-specific fields to struct mce
- Cleanups
* tag 'ras_core_for_v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
EDAC/mce_amd: Add support for FRU text in MCA
x86/mce/apei: Handle variable SMCA BERT record size
x86/MCE/AMD: Add support for new MCA_SYND{1,2} registers
tracing: Add __print_dynamic_array() helper
x86/mce: Add wrapper for struct mce to export vendor specific info
x86/mce/intel: Use MCG_BANKCNT_MASK instead of 0xff
x86/mce/mcelog: Use xchg() to get and clear the flags
Pull 'struct fd' class updates from Al Viro:
"The bulk of struct fd memory safety stuff
Making sure that struct fd instances are destroyed in the same scope
where they'd been created, getting rid of reassignments and passing
them by reference, converting to CLASS(fd{,_pos,_raw}).
We are getting very close to having the memory safety of that stuff
trivial to verify"
* tag 'pull-fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (28 commits)
deal with the last remaing boolean uses of fd_file()
css_set_fork(): switch to CLASS(fd_raw, ...)
memcg_write_event_control(): switch to CLASS(fd)
assorted variants of irqfd setup: convert to CLASS(fd)
do_pollfd(): convert to CLASS(fd)
convert do_select()
convert vfs_dedupe_file_range().
convert cifs_ioctl_copychunk()
convert media_request_get_by_fd()
convert spu_run(2)
switch spufs_calls_{get,put}() to CLASS() use
convert cachestat(2)
convert do_preadv()/do_pwritev()
fdget(), more trivial conversions
fdget(), trivial conversions
privcmd_ioeventfd_assign(): don't open-code eventfd_ctx_fdget()
o2hb_region_dev_store(): avoid goto around fdget()/fdput()
introduce "fd_pos" class, convert fdget_pos() users to it.
fdget_raw() users: switch to CLASS(fd_raw)
convert vmsplice() to CLASS(fd)
...
Remove unnecessary CONFIG_NUMA #ifdef around numa_add_cpu() since the
function is already properly handled in <asm/numa.h> for both NUMA and
non-NUMA configurations. For !CONFIG_NUMA builds, numa_add_cpu() is
defined as an empty function.
Simplify the code without any functionality change.
Testing: Build CONFIG_NUMA=n
Signed-off-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20241112072346.428623-1-shivankg@amd.com
When flag_is_changeable_p() is unused, it prevents kernel builds
with clang, `make W=1` and CONFIG_WERROR=y:
arch/x86/kernel/cpu/common.c:351:19: error: unused function 'flag_is_changeable_p' [-Werror,-Wunused-function]
351 | static inline int flag_is_changeable_p(u32 flag)
| ^~~~~~~~~~~~~~~~~~~~
Fix this by moving core around to make sure flag_is_changeable_p() is
always being used.
See also commit 6863f5643d ("kbuild: allow Clang to find unused static
inline functions for W=1 build").
While at it, fix the argument type to be unsigned long along with
the local variables, although it currently only runs in 32-bit cases.
Besides that, makes it return boolean instead of int. This induces
the change of the returning type of have_cpuid_p() to be boolean
as well.
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Link: https://lore.kernel.org/all/20241108153105.1578186-1-andriy.shevchenko%40linux.intel.com
GCC and Clang both implement stack protector support based on Thread Local
Storage (TLS) variables, and this is used in the kernel to implement per-task
stack cookies, by copying a task's stack cookie into a per-CPU variable every
time it is scheduled in.
Both now also implement -mstack-protector-guard-symbol=, which permits the TLS
variable to be specified directly. This is useful because it will allow to
move away from using a fixed offset of 40 bytes into the per-CPU area on
x86_64, which requires a lot of special handling in the per-CPU code and the
runtime relocation code.
However, while GCC is rather lax in its implementation of this command line
option, Clang actually requires that the provided symbol name refers to a TLS
variable (i.e., one declared with __thread), although it also permits the
variable to be undeclared entirely, in which case it will use an implicit
declaration of the right type.
The upshot of this is that Clang will emit the correct references to the stack
cookie variable in most cases, e.g.,
10d: 64 a1 00 00 00 00 mov %fs:0x0,%eax
10f: R_386_32 __stack_chk_guard
However, if a non-TLS definition of the symbol in question is visible in the
same compilation unit (which amounts to the whole of vmlinux if LTO is
enabled), it will drop the per-CPU prefix and emit a load from a bogus
address.
Work around this by using a symbol name that never occurs in C code, and emit
it as an alias in the linker script.
Fixes: 3fb0fdb3bb ("x86/stackprotector/32: Make the canary into a regular percpu variable")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Cc: stable@vger.kernel.org
Link: https://github.com/ClangBuiltLinux/linux/issues/1854
Link: https://lore.kernel.org/r/20241105155801.1779119-2-brgerst@gmail.com
A number of Zen4 client SoCs advertise the ability to use virtualized
VMLOAD/VMSAVE, but using these instructions is reported to be a cause
of a random host reboot.
These instructions aren't intended to be advertised on Zen4 client
so clear the capability.
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=219009
fdget() is the first thing done in scope, all matching fdput() are
immediately followed by leaving the scope.
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The ACPI Boot Error Record Table (BERT) is being used by the kernel to report
errors that occurred in a previous boot. On some modern AMD systems, these
very errors within the BERT are reported through the x86 Common Platform Error
Record (CPER) format which consists of one or more Processor Context
Information Structures.
These context structures provide a starting address and represent an x86 MSR
range in which the data constitutes a contiguous set of MSRs starting from,
and including the starting address.
It's common, for AMD systems that implement this behavior, that the MSR range
represents the MCAX register space used for the Scalable MCA feature. The
apei_smca_report_x86_error() function decodes and passes this information
through the MCE notifier chain. However, this function assumes a fixed
register size based on the original HW/FW implementation.
This assumption breaks with the addition of two new MCAX registers viz.
MCA_SYND1 and MCA_SYND2. These registers are added at the end of the MCAX
register space, so they won't be included when decoding the CPER data.
Rework apei_smca_report_x86_error() to support a variable register array size.
This covers any case where the MSR context information starts at the MCAX
address for MCA_STATUS and ends at any other register within the MCAX register
space.
[ Yazen: Add Avadhut as co-developer for wrapper changes.]
[ bp: Massage. ]
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Co-developed-by: Avadhut Naik <avadhut.naik@amd.com>
Signed-off-by: Avadhut Naik <avadhut.naik@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Link: https://lore.kernel.org/r/20241022194158.110073-5-avadhut.naik@amd.com
Starting with Zen4, AMD's Scalable MCA systems incorporate two new registers:
MCA_SYND1 and MCA_SYND2.
These registers will include supplemental error information in addition to the
existing MCA_SYND register. The data within these registers is considered
valid if MCA_STATUS[SyndV] is set.
Userspace error decoding tools like rasdaemon gather related hardware error
information through the tracepoints.
Therefore, export these two registers through the mce_record tracepoint so
that tools like rasdaemon can parse them and output the supplemental error
information like FRU text contained in them.
[ bp: Massage. ]
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Avadhut Naik <avadhut.naik@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Link: https://lore.kernel.org/r/20241022194158.110073-4-avadhut.naik@amd.com
Currently, exporting new additional machine check error information
involves adding new fields for the same at the end of the struct mce.
This additional information can then be consumed through mcelog or
tracepoint.
However, as new MSRs are being added (and will be added in the future)
by CPU vendors on their newer CPUs with additional machine check error
information to be exported, the size of struct mce will balloon on some
CPUs, unnecessarily, since those fields are vendor-specific. Moreover,
different CPU vendors may export the additional information in varying
sizes.
The problem particularly intensifies since struct mce is exposed to
userspace as part of UAPI. It's bloating through vendor-specific data
should be avoided to limit the information being sent out to userspace.
Add a new structure mce_hw_err to wrap the existing struct mce. The same
will prevent its ballooning since vendor-specifc data, if any, can now be
exported through a union within the wrapper structure and through
__dynamic_array in mce_record tracepoint.
Furthermore, new internal kernel fields can be added to the wrapper
struct without impacting the user space API.
[ bp: Restore reverse x-mas tree order of function vars declarations. ]
Suggested-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Avadhut Naik <avadhut.naik@amd.com>
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Link: https://lore.kernel.org/r/20241022194158.110073-2-avadhut.naik@amd.com
Add a new feature bit that indicates support for workload-based heuristic
feedback to OS for scheduling decisions.
When the bit set, threads are classified during runtime into enumerated
classes. The classes represent thread performance/power characteristics
that may benefit from special scheduling behaviors.
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Link: https://lore.kernel.org/r/20241028020251.8085-4-mario.limonciello@amd.com
Pull x86 fixes from Borislav Petkov:
- Prevent a certain range of pages which get marked as hypervisor-only,
to get allocated to a CoCo (SNP) guest which cannot use them and thus
fail booting
- Fix the microcode loader on AMD to pay attention to the stepping of a
patch and to handle the case where a BIOS config option splits the
machine into logical NUMA nodes per L3 cache slice
- Disable LAM from being built by default due to security concerns
* tag 'x86_urgent_for_v6.12_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sev: Ensure that RMP table fixups are reserved
x86/microcode/AMD: Split load_microcode_amd()
x86/microcode/AMD: Pay attention to the stepping dynamically
x86/lam: Disable ADDRESS_MASKING in most cases
Sometimes it is required to take actions based on if a CPU is a performance or
efficiency core. As an example, intel_pstate driver uses the Intel core-type
to determine CPU scaling. Also, some CPU vulnerabilities only affect
a specific CPU type, like RFDS only affects Intel Atom. Hybrid systems that
have variants P+E, P-only(Core) and E-only(Atom), it is not straightforward to
identify which variant is affected by a type specific vulnerability.
Such processors do have CPUID field that can uniquely identify them. Like,
P+E, P-only and E-only enumerates CPUID.1A.CORE_TYPE identification, while P+E
additionally enumerates CPUID.7.HYBRID. Based on this information, it is
possible for boot CPU to identify if a system has mixed CPU types.
Add a new field hw_cpu_type to struct cpuinfo_topology that stores the
hardware specific CPU type. This saves the overhead of IPIs to get the CPU
type of a different CPU. CPU type is populated early in the boot process,
before vulnerabilities are enumerated.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20241025171459.1093-5-mario.limonciello@amd.com
It turns out that AMD has a "Meltdown Lite(tm)" issue with non-canonical
accesses in kernel space. And so using just the high bit to decide
whether an access is in user space or kernel space ends up with the good
old "leak speculative data" if you have the right gadget using the
result:
CVE-2020-12965 “Transient Execution of Non-Canonical Accesses“
Now, the kernel surrounds the access with a STAC/CLAC pair, and those
instructions end up serializing execution on older Zen architectures,
which closes the speculation window.
But that was true only up until Zen 5, which renames the AC bit [1].
That improves performance of STAC/CLAC a lot, but also means that the
speculation window is now open.
Note that this affects not just the new address masking, but also the
regular valid_user_address() check used by access_ok(), and the asm
version of the sign bit check in the get_user() helpers.
It does not affect put_user() or clear_user() variants, since there's no
speculative result to be used in a gadget for those operations.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Link: https://lore.kernel.org/all/80d94591-1297-4afb-b510-c665efd37f10@citrix.com/
Link: https://lore.kernel.org/all/20241023094448.GAZxjFkEOOF_DM83TQ@fat_crate.local/ [1]
Link: https://www.amd.com/en/resources/product-security/bulletin/amd-sb-1010.html
Link: https://arxiv.org/pdf/2108.10771
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Tested-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com> # LAM case
Fixes: 2865baf540 ("x86: support user address masking instead of non-speculative conditional")
Fixes: 6014bc2756 ("x86-64: make access_ok() independent of LAM")
Fixes: b19b74bc99 ("x86/mm: Rework address range check in get_user() and put_user()")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, an unconditional cache flush is performed during every
microcode update. Although the original changelog did not mention
a specific erratum, this measure was primarily intended to address
a specific microcode bug, the load of which has already been blocked by
is_blacklisted(). Therefore, this cache flush is no longer necessary.
Additionally, the side effects of doing this have been overlooked. It
increases CPU rendezvous time during late loading, where the cache flush
takes between 1x to 3.5x longer than the actual microcode update.
Remove native_wbinvd() and update the erratum name to align with the
latest errata documentation, document ID 334163 Version 022US.
[ bp: Zap the flaky documentation URL. ]
Fixes: 91df9fdf51 ("x86/microcode/intel: Writeback and invalidate caches before updating microcode")
Reported-by: Yan Hua Wu <yanhua1.wu@intel.com>
Reported-by: William Xie <william.xie@intel.com>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Ashok Raj <ashok.raj@intel.com>
Tested-by: Yan Hua Wu <yanhua1.wu@intel.com>
Link: https://lore.kernel.org/r/20241001161042.465584-2-chang.seok.bae@intel.com
This function should've been split a long time ago because it is used in
two paths:
1) On the late loading path, when the microcode is loaded through the
request_firmware interface
2) In the save_microcode_in_initrd() path which collects all the
microcode patches which are relevant for the current system before
the initrd with the microcode container has been jettisoned.
In that path, it is not really necessary to iterate over the nodes on
a system and match a patch however it didn't cause any trouble so it
was left for a later cleanup
However, that later cleanup was expedited by the fact that Jens was
enabling "Use L3 as a NUMA node" in the BIOS setting in his machine and
so this causes the NUMA CPU masks used in cpumask_of_node() to be
generated *after* 2) above happened on the first node. Which means, all
those masks were funky, wrong, uninitialized and whatnot, leading to
explosions when dereffing c->microcode in load_microcode_amd().
So split that function and do only the necessary work needed at each
stage.
Fixes: 94838d230a ("x86/microcode/AMD: Use the family,model,stepping encoded in the patch ID")
Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/91194406-3fdf-4e38-9838-d334af538f74@kernel.dk
Commit in Fixes changed how a microcode patch is loaded on Zen and newer but
the patch matching needs to happen with different rigidity, depending on what
is being done:
1) When the patch is added to the patches cache, the stepping must be ignored
because the driver still supports different steppings per system
2) When the patch is matched for loading, then the stepping must be taken into
account because each CPU needs the patch matching its exact stepping
Take care of that by making the matching smarter.
Fixes: 94838d230a ("x86/microcode/AMD: Use the family,model,stepping encoded in the patch ID")
Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/91194406-3fdf-4e38-9838-d334af538f74@kernel.dk
Pull x86 fixes from Borislav Petkov:
- Explicitly disable the TSC deadline timer when going idle to address
some CPU errata in that area
- Do not apply the Zenbleed fix on anything else except AMD Zen2 on the
late microcode loading path
- Clear CPU buffers later in the NMI exit path on 32-bit to avoid
register clearing while they still contain sensitive data, for the
RDFS mitigation
- Do not clobber EFLAGS.ZF with VERW on the opportunistic SYSRET exit
path on 32-bit
- Fix parsing issues of memory bandwidth specification in sysfs for
resctrl's memory bandwidth allocation feature
- Other small cleanups and improvements
* tag 'x86_urgent_for_v6.12_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/apic: Always explicitly disarm TSC-deadline timer
x86/CPU/AMD: Only apply Zenbleed fix for Zen2 during late microcode load
x86/bugs: Use code segment selector for VERW operand
x86/entry_32: Clear CPU buffers after register restore in NMI return
x86/entry_32: Do not clobber user EFLAGS.ZF
x86/resctrl: Annotate get_mem_config() functions as __init
x86/resctrl: Avoid overflow in MB settings in bw_validate()
x86/amd_nb: Add new PCI ID for AMD family 1Ah model 20h
'mon_info' is already zeroed in the list_for_each_entry() loop below. There
is no need to explicitly initialize it here. It just wastes some space and
cycles.
Remove this un-needed code.
On a x86_64, with allmodconfig:
Before:
======
text data bss dec hex filename
74967 5103 1880 81950 1401e arch/x86/kernel/cpu/resctrl/rdtgroup.o
After:
=====
text data bss dec hex filename
74903 5103 1880 81886 13fde arch/x86/kernel/cpu/resctrl/rdtgroup.o
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/b2ebc809c8b6c6440d17b12ccf7c2d29aaafd488.1720868538.git.christophe.jaillet@wanadoo.fr
Commit
f69759be25 ("x86/CPU/AMD: Move Zenbleed check to the Zen2 init function")
causes a bit in the DE_CFG MSR to get set erroneously after a microcode late
load.
The microcode late load path calls into amd_check_microcode() and subsequently
zen2_zenbleed_check(). Since the above commit removes the cpu_has_amd_erratum()
call from zen2_zenbleed_check(), this will cause all non-Zen2 CPUs to go
through the function and set the bit in the DE_CFG MSR.
Call into the Zenbleed fix path on Zen2 CPUs only.
[ bp: Massage commit message, use cpu_feature_enabled(). ]
Fixes: f69759be25 ("x86/CPU/AMD: Move Zenbleed check to the Zen2 init function")
Signed-off-by: John Allen <john.allen@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20240923164404.27227-1-john.allen@amd.com
Since X86_FEATURE_ENTRY_IBPB will invalidate all harmful predictions
with IBPB, no software-based untraining of returns is needed anymore.
Currently, this change affects retbleed and SRSO mitigations so if
either of the mitigations is doing IBPB and the other one does the
software sequence, the latter is not needed anymore.
[ bp: Massage commit message. ]
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Johannes Wikner <kwikner@ethz.ch>
Cc: <stable@kernel.org>
entry_ibpb() is designed to follow Intel's IBPB specification regardless
of CPU. This includes invalidating RSB entries.
Hence, if IBPB on VMEXIT has been selected, entry_ibpb() as part of the
RET untraining in the VMEXIT path will take care of all BTB and RSB
clearing so there's no need to explicitly fill the RSB anymore.
[ bp: Massage commit message. ]
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Johannes Wikner <kwikner@ethz.ch>
Cc: <stable@kernel.org>
Set this flag if the CPU has an IBPB implementation that does not
invalidate return target predictions. Zen generations < 4 do not flush
the RSB when executing an IBPB and this bug flag denotes that.
[ bp: Massage. ]
Signed-off-by: Johannes Wikner <kwikner@ethz.ch>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
After a recent LLVM change [1] that deduces __cold on functions that only call
cold code (such as __init functions), there is a section mismatch warning from
__get_mem_config_intel(), which got moved to .text.unlikely. as a result of
that optimization:
WARNING: modpost: vmlinux: section mismatch in reference: \
__get_mem_config_intel+0x77 (section: .text.unlikely.) -> thread_throttle_mode_init (section: .init.text)
Mark __get_mem_config_intel() as __init as well since it is only called
from __init code, which clears up the warning.
While __rdt_get_mem_config_amd() does not exhibit a warning because it
does not call any __init code, it is a similar function that is only
called from __init code like __get_mem_config_intel(), so mark it __init
as well to keep the code symmetrical.
CONFIG_SECTION_MISMATCH_WARN_ONLY=n would turn this into a fatal error.
Fixes: 05b93417ce ("x86/intel_rdt/mba: Add primary support for Memory Bandwidth Allocation (MBA)")
Fixes: 4d05bf71f1 ("x86/resctrl: Introduce AMD QOS feature")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Cc: <stable@kernel.org>
Link: 6b11573b8c [1]
Link: https://lore.kernel.org/r/20240917-x86-restctrl-get_mem_config_intel-init-v3-1-10d521256284@kernel.org
The resctrl schemata file supports specifying memory bandwidth associated with
the Memory Bandwidth Allocation (MBA) feature via a percentage (this is the
default) or bandwidth in MiBps (when resctrl is mounted with the "mba_MBps"
option).
The allowed range for the bandwidth percentage is from
/sys/fs/resctrl/info/MB/min_bandwidth to 100, using a granularity of
/sys/fs/resctrl/info/MB/bandwidth_gran. The supported range for the MiBps
bandwidth is 0 to U32_MAX.
There are two issues with parsing of MiBps memory bandwidth:
* The user provided MiBps is mistakenly rounded up to the granularity
that is unique to percentage input.
* The user provided MiBps is parsed using unsigned long (thus accepting
values up to ULONG_MAX), and then assigned to u32 that could result in
overflow.
Do not round up the MiBps value and parse user provided bandwidth as the u32
it is intended to be. Use the appropriate kstrtou32() that can detect out of
range values.
Fixes: 8205a078ba ("x86/intel_rdt/mba_sc: Add schemata support")
Fixes: 6ce1560d35 ("x86/resctrl: Switch over to the resctrl mbps_val list")
Co-developed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Martin Kletzander <nert.pinx@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
