The introduction of clocksource_tsc_early broke the functionality of
"tsc=reliable" and "tsc=nowatchdog" command line parameters, since
clocksource_tsc_early is unconditionally registered with
CLOCK_SOURCE_MUST_VERIFY and thus put on the watchdog list.
This can cause the TSC to be declared unstable during boot:
clocksource: timekeeping watchdog on CPU0: Marking clocksource
'tsc-early' as unstable because the skew is too large:
clocksource: 'refined-jiffies' wd_now: fffb7018 wd_last: fffb6e9d
mask: ffffffff
clocksource: 'tsc-early' cs_now: 68a6a7070f6a0 cs_last: 68a69ab6f74d6
mask: ffffffffffffffff
tsc: Marking TSC unstable due to clocksource watchdog
The corresponding elapsed times are cs_nsec=1224152026 and wd_nsec=378942392, so
the watchdog differs from TSC by 0.84 seconds.
This happens when HPET is not available and jiffies are used as the TSC
watchdog instead and the jiffies update is not happening due to lost timer
interrupts in periodic mode, which can happen e.g. with expensive debug
mechanisms enabled or under massive overload conditions in virtualized
environments.
Before the introduction of the early TSC clocksource the command line
parameters "tsc=reliable" and "tsc=nowatchdog" could be used to work around
this issue.
Restore the behaviour by disabling the watchdog if requested on the kernel
command line.
[ tglx: Clarify changelog ]
Fixes: aa83c45762 ("x86/tsc: Introduce early tsc clocksource")
Signed-off-by: Michael Zhivich <mzhivich@akamai.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191024175945.14338-1-mzhivich@akamai.com
Cyrill reported the following crash:
BUG: unable to handle page fault for address: 0000000000001ff0
#PF: supervisor read access in kernel mode
RIP: 0010:get_stack_info+0xb3/0x148
It turns out that if the stack tracer is invoked before the exception stack
mappings are initialized in_exception_stack() can erroneously classify an
invalid address as an address inside of an exception stack:
begin = this_cpu_read(cea_exception_stacks); <- 0
end = begin + sizeof(exception stacks);
i.e. any address between 0 and end will be considered as exception stack
address and the subsequent code will then try to derefence the resulting
stack frame at a non mapped address.
end = begin + (unsigned long)ep->size;
==> end = 0x2000
regs = (struct pt_regs *)end - 1;
==> regs = 0x2000 - sizeof(struct pt_regs *) = 0x1ff0
info->next_sp = (unsigned long *)regs->sp;
==> Crashes due to accessing 0x1ff0
Prevent this by checking the validity of the cea_exception_stack base
address and bailing out if it is zero.
Fixes: afcd21dad8 ("x86/dumpstack/64: Use cpu_entry_area instead of orig_ist")
Reported-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Cyrill Gorcunov <gorcunov@gmail.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1910231950590.1852@nanos.tec.linutronix.de
The removal of the LDR initialization in the bigsmp_32 APIC code unearthed
a problem in setup_local_APIC().
The code checks unconditionally for a mismatch of the logical APIC id by
comparing the early APIC id which was initialized in get_smp_config() with
the actual LDR value in the APIC.
Due to the removal of the bogus LDR initialization the check now can
trigger on bigsmp_32 APIC systems emitting a warning for every booting
CPU. This is of course a false positive because the APIC is not using
logical destination mode.
Restrict the check and the possibly resulting fixup to systems which are
actually using the APIC in logical destination mode.
[ tglx: Massaged changelog and added Cc stable ]
Fixes: bae3a8d330 ("x86/apic: Do not initialize LDR and DFR for bigsmp")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/666d8f91-b5a8-1afd-7add-821e72a35f03@suse.com
When setting up sizes and offsets for legacy header entries the code uses
hardcoded 0/1 instead of the corresponding enum values XFEATURE_FP and
XFEATURE_SSE.
Replace the hardcoded numbers which enhances readability of the code and
also makes this code the first user of those enum values..
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191101130153.GG1615@uranus.lan
commit 8ff925e10f ("x86/xsaves: Clean up code in xstate offsets
computation in xsave area") introduced an allocation of 64 entries for
xstate_comp_offsets while the code only handles up to XFEATURE_MAX entries.
For this reason xstate_offsets and xstate_sizes are already defined with
the explicit XFEATURE_MAX limit.
Do the same for compressed format for consistency sake.
As the changelog of that commit is not giving any information it's assumed
that the main idea was to cover all possible bits in xfeatures_mask, but
this doesn't explain why other variables such as the non-compacted offsets
and sizes are explicitely limited to XFEATURE_MAX.
For consistency it's better to use the XFEATURE_MAX limit everywhere and
extend it on demand when new features get implemented at the hardware
level and subsequently supported by the kernel.
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191101124228.GF1615@uranus.lan
With some Intel processors, putting the same virtual address in the TLB
as both a 4 KiB and 2 MiB page can confuse the instruction fetch unit
and cause the processor to issue a machine check resulting in a CPU lockup.
Unfortunately when EPT page tables use huge pages, it is possible for a
malicious guest to cause this situation.
Add a knob to mark huge pages as non-executable. When the nx_huge_pages
parameter is enabled (and we are using EPT), all huge pages are marked as
NX. If the guest attempts to execute in one of those pages, the page is
broken down into 4K pages, which are then marked executable.
This is not an issue for shadow paging (except nested EPT), because then
the host is in control of TLB flushes and the problematic situation cannot
happen. With nested EPT, again the nested guest can cause problems shadow
and direct EPT is treated in the same way.
[ tglx: Fixup default to auto and massage wording a bit ]
Originally-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Add the new cpu family ATOM_TREMONT_D to the cpu vunerability
whitelist. ATOM_TREMONT_D is not affected by X86_BUG_ITLB_MULTIHIT.
ATOM_TREMONT_D might have mitigations against other issues as well, but
only the ITLB multihit mitigation is confirmed at this point.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Some processors may incur a machine check error possibly resulting in an
unrecoverable CPU lockup when an instruction fetch encounters a TLB
multi-hit in the instruction TLB. This can occur when the page size is
changed along with either the physical address or cache type. The relevant
erratum can be found here:
https://bugzilla.kernel.org/show_bug.cgi?id=205195
There are other processors affected for which the erratum does not fully
disclose the impact.
This issue affects both bare-metal x86 page tables and EPT.
It can be mitigated by either eliminating the use of large pages or by
using careful TLB invalidations when changing the page size in the page
tables.
Just like Spectre, Meltdown, L1TF and MDS, a new bit has been allocated in
MSR_IA32_ARCH_CAPABILITIES (PSCHANGE_MC_NO) and will be set on CPUs which
are mitigated against this issue.
Signed-off-by: Vineela Tummalapalli <vineela.tummalapalli@intel.com>
Co-developed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
When a mon group is being deleted, rdtgrp->flags is set to RDT_DELETED
in rdtgroup_rmdir_mon() firstly. The structure of rdtgrp will be freed
until rdtgrp->waitcount is dropped to 0 in rdtgroup_kn_unlock() later.
During the window of deleting a mon group, if an application calls
rdtgroup_mondata_show() to read mondata under this mon group,
'rdtgrp' returned from rdtgroup_kn_lock_live() is a NULL pointer when
rdtgrp->flags is RDT_DELETED. And then 'rdtgrp' is passed in this path:
rdtgroup_mondata_show() --> mon_event_read() --> mon_event_count().
Thus it results in NULL pointer dereference in mon_event_count().
Check 'rdtgrp' in rdtgroup_mondata_show(), and return -ENOENT
immediately when reading mondata during the window of deleting a mon
group.
Fixes: d89b737901 ("x86/intel_rdt/cqm: Add mon_data")
Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: pei.p.jia@intel.com
Cc: Reinette Chatre <reinette.chatre@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/1572326702-27577-1-git-send-email-xiaochen.shen@intel.com
There is a general consensus that TSX usage is not largely spread while
the history shows there is a non trivial space for side channel attacks
possible. Therefore the tsx is disabled by default even on platforms
that might have a safe implementation of TSX according to the current
knowledge. This is a fair trade off to make.
There are, however, workloads that really do benefit from using TSX and
updating to a newer kernel with TSX disabled might introduce a
noticeable regressions. This would be especially a problem for Linux
distributions which will provide TAA mitigations.
Introduce config options X86_INTEL_TSX_MODE_OFF, X86_INTEL_TSX_MODE_ON
and X86_INTEL_TSX_MODE_AUTO to control the TSX feature. The config
setting can be overridden by the tsx cmdline options.
[ bp: Text cleanups from Josh. ]
Suggested-by: Borislav Petkov <bpetkov@suse.de>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
TSX Async Abort (TAA) is a side channel vulnerability to the internal
buffers in some Intel processors similar to Microachitectural Data
Sampling (MDS). In this case, certain loads may speculatively pass
invalid data to dependent operations when an asynchronous abort
condition is pending in a TSX transaction.
This includes loads with no fault or assist condition. Such loads may
speculatively expose stale data from the uarch data structures as in
MDS. Scope of exposure is within the same-thread and cross-thread. This
issue affects all current processors that support TSX, but do not have
ARCH_CAP_TAA_NO (bit 8) set in MSR_IA32_ARCH_CAPABILITIES.
On CPUs which have their IA32_ARCH_CAPABILITIES MSR bit MDS_NO=0,
CPUID.MD_CLEAR=1 and the MDS mitigation is clearing the CPU buffers
using VERW or L1D_FLUSH, there is no additional mitigation needed for
TAA. On affected CPUs with MDS_NO=1 this issue can be mitigated by
disabling the Transactional Synchronization Extensions (TSX) feature.
A new MSR IA32_TSX_CTRL in future and current processors after a
microcode update can be used to control the TSX feature. There are two
bits in that MSR:
* TSX_CTRL_RTM_DISABLE disables the TSX sub-feature Restricted
Transactional Memory (RTM).
* TSX_CTRL_CPUID_CLEAR clears the RTM enumeration in CPUID. The other
TSX sub-feature, Hardware Lock Elision (HLE), is unconditionally
disabled with updated microcode but still enumerated as present by
CPUID(EAX=7).EBX{bit4}.
The second mitigation approach is similar to MDS which is clearing the
affected CPU buffers on return to user space and when entering a guest.
Relevant microcode update is required for the mitigation to work. More
details on this approach can be found here:
https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/mds.html
The TSX feature can be controlled by the "tsx" command line parameter.
If it is force-enabled then "Clear CPU buffers" (MDS mitigation) is
deployed. The effective mitigation state can be read from sysfs.
[ bp:
- massage + comments cleanup
- s/TAA_MITIGATION_TSX_DISABLE/TAA_MITIGATION_TSX_DISABLED/g - Josh.
- remove partial TAA mitigation in update_mds_branch_idle() - Josh.
- s/tsx_async_abort_cmdline/tsx_async_abort_parse_cmdline/g
]
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Add a kernel cmdline parameter "tsx" to control the Transactional
Synchronization Extensions (TSX) feature. On CPUs that support TSX
control, use "tsx=on|off" to enable or disable TSX. Not specifying this
option is equivalent to "tsx=off". This is because on certain processors
TSX may be used as a part of a speculative side channel attack.
Carve out the TSX controlling functionality into a separate compilation
unit because TSX is a CPU feature while the TSX async abort control
machinery will go to cpu/bugs.c.
[ bp: - Massage, shorten and clear the arg buffer.
- Clarifications of the tsx= possible options - Josh.
- Expand on TSX_CTRL availability - Pawan. ]
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
We get two warning when build kernel with W=1:
arch/x86/kernel/kvm.c:872:6: warning: no previous prototype for ‘arch_haltpoll_enable’ [-Wmissing-prototypes]
arch/x86/kernel/kvm.c:885:6: warning: no previous prototype for ‘arch_haltpoll_disable’ [-Wmissing-prototypes]
Including the missing head file can fix this.
Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
History lesson courtesy of Steve:
"When ftrace first was introduced to the kernel, it used gcc's
mcount profiling mechanism. The mcount mechanism would add a call to
"mcount" at the start of every function but after the stack frame was
set up. Later, in gcc 4.6, gcc introduced -mfentry, that would create a
call to "__fentry__" instead of "mcount", before the stack frame was
set up. In order to handle both cases, ftrace defined a macro
"function_hook" that would be either "mcount" or "__fentry__" depending
on which one was being used.
The Linux kernel no longer supports the "mcount" method, thus there's
no reason to keep the "function_hook" define around. Simply use
"__fentry__", as there is no ambiguity to the name anymore."
Drop it everywhere.
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20191018124800.0a7006bb@gandalf.local.home
ioapic_irqd_[un]mask() are misnomers as both functions do way more than
masking and unmasking the interrupt line. Both deal with the moving the
affinity of the interrupt within interrupt context. The mask/unmask is just
a tiny part of the functionality.
Rename them to ioapic_prepare/finish_move(), fixup the call sites and
rename the related variables in the code to reflect what this is about.
No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Link: https://lkml.kernel.org/r/20191017101938.412489856@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There is an issue with threaded interrupts which are marked ONESHOT
and using the fasteoi handler:
if (IS_ONESHOT())
mask_irq();
....
cond_unmask_eoi_irq()
chip->irq_eoi();
if (setaffinity_pending) {
mask_ioapic();
...
move_affinity();
unmask_ioapic();
}
So if setaffinity is pending the interrupt will be moved and then
unconditionally unmasked at the ioapic level, which is wrong in two
aspects:
1) It should be kept masked up to the point where the threaded handler
finished.
2) The physical chip state and the software masked state are inconsistent
Guard both the mask and the unmask with a check for the software masked
state. If the line is marked masked then the ioapic line is also masked, so
both mask_ioapic() and unmask_ioapic() can be skipped safely.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Fixes: 3aa551c9b4 ("genirq: add threaded interrupt handler support")
Link: https://lkml.kernel.org/r/20191017101938.321393687@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 fixes from Thomas Gleixner:
"A small set of x86 fixes:
- Prevent a NULL pointer dereference in the X2APIC code in case of a
CPU hotplug failure.
- Prevent boot failures on HP superdome machines by invalidating the
level2 kernel pagetable entries outside of the kernel area as
invalid so BIOS reserved space won't be touched unintentionally.
Also ensure that memory holes are rounded up to the next PMD
boundary correctly.
- Enable X2APIC support on Hyper-V to prevent boot failures.
- Set the paravirt name when running on Hyper-V for consistency
- Move a function under the appropriate ifdef guard to prevent build
warnings"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/boot/acpi: Move get_cmdline_acpi_rsdp() under #ifdef guard
x86/hyperv: Set pv_info.name to "Hyper-V"
x86/apic/x2apic: Fix a NULL pointer deref when handling a dying cpu
x86/hyperv: Make vapic support x2apic mode
x86/boot/64: Round memory hole size up to next PMD page
x86/boot/64: Make level2_kernel_pgt pages invalid outside kernel area
Use the new SYM_DATA, SYM_DATA_START, and SYM_DATA_END in both 32 and 64
bit head_*.S. In the 64-bit version, define also
SYM_DATA_START_PAGE_ALIGNED locally using the new SYM_START. It is used
in the code instead of NEXT_PAGE() which was defined in this file and
had been using the obsolete macro GLOBAL().
Now, the data in the 64-bit object file look sane:
Value Size Type Bind Vis Ndx Name
0000 4096 OBJECT GLOBAL DEFAULT 15 init_level4_pgt
1000 4096 OBJECT GLOBAL DEFAULT 15 level3_kernel_pgt
2000 2048 OBJECT GLOBAL DEFAULT 15 level2_kernel_pgt
3000 4096 OBJECT GLOBAL DEFAULT 15 level2_fixmap_pgt
4000 4096 OBJECT GLOBAL DEFAULT 15 level1_fixmap_pgt
5000 2 OBJECT GLOBAL DEFAULT 15 early_gdt_descr
5002 8 OBJECT LOCAL DEFAULT 15 early_gdt_descr_base
500a 8 OBJECT GLOBAL DEFAULT 15 phys_base
0000 8 OBJECT GLOBAL DEFAULT 17 initial_code
0008 8 OBJECT GLOBAL DEFAULT 17 initial_gs
0010 8 OBJECT GLOBAL DEFAULT 17 initial_stack
0000 4 OBJECT GLOBAL DEFAULT 19 early_recursion_flag
1000 4096 OBJECT GLOBAL DEFAULT 19 early_level4_pgt
2000 0x40000 OBJECT GLOBAL DEFAULT 19 early_dynamic_pgts
0000 4096 OBJECT GLOBAL DEFAULT 22 empty_zero_page
All have correct size and type now.
Note that this also removes implicit 16B alignment previously inserted
by ENTRY:
* initial_code, setup_once_ref, initial_page_table, initial_stack,
boot_gdt are still aligned
* early_gdt_descr is now properly aligned as was intended before ENTRY
was added there long time ago
* phys_base's alignment is kept by an explicitly added new alignment
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Cao jin <caoj.fnst@cn.fujitsu.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: linux-arch@vger.kernel.org
Cc: Maran Wilson <maran.wilson@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20191011115108.12392-12-jslaby@suse.cz
Use the newly added SYM_CODE_START_LOCAL* to annotate beginnings of
all pseudo-functions (those ending with END until now) which do not
have ".globl" annotation. This is needed to balance END for tools that
generate debuginfo. Note that ENDs are switched to SYM_CODE_END too so
that everybody can see the pairing.
C-like functions (which handle frame ptr etc.) are not annotated here,
hence SYM_CODE_* macros are used here, not SYM_FUNC_*. Note that the
32bit version of early_idt_handler_common already had ENDPROC -- switch
that to SYM_CODE_END for the same reason as above (and to be the same as
64bit).
While early_idt_handler_common is LOCAL, it's name is not prepended with
".L" as it happens to appear in call traces.
bad_get_user*, and bad_put_user are now aligned, as they are separate
functions. They do not mind to be aligned -- no need to be compact
there.
early_idt_handler_common is aligned now too, as it is after
early_idt_handler_array, so as well no need to be compact there.
verify_cpu is self-standing and included in other .S files, so align it
too.
The others have alignment preserved to what it used to be (using the
_NOALIGN variant of macros).
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Alexios Zavras <alexios.zavras@intel.com>
Cc: Allison Randal <allison@lohutok.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Cao jin <caoj.fnst@cn.fujitsu.com>
Cc: Enrico Weigelt <info@metux.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: linux-arch@vger.kernel.org
Cc: Maran Wilson <maran.wilson@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20191011115108.12392-6-jslaby@suse.cz
There are functions in relocate_kernel_{32,64}.c which are not
annotated. This makes automatic annotations on them rather hard. So
annotate all the functions now.
Note that these are not C-like functions, so FUNC is not used. Instead
CODE markers are used. Also the functions are not aligned, so the
NOALIGN versions are used:
- SYM_CODE_START_NOALIGN
- SYM_CODE_START_LOCAL_NOALIGN
- SYM_CODE_END
The result is:
0000 108 NOTYPE GLOBAL DEFAULT 1 relocate_kernel
006c 165 NOTYPE LOCAL DEFAULT 1 identity_mapped
0146 127 NOTYPE LOCAL DEFAULT 1 swap_pages
0111 53 NOTYPE LOCAL DEFAULT 1 virtual_mapped
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Alexios Zavras <alexios.zavras@intel.com>
Cc: Allison Randal <allison@lohutok.net>
Cc: Enrico Weigelt <info@metux.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-arch@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20191011115108.12392-4-jslaby@suse.cz
On modern CPUs it is quite normal that the temperature limits are
reached and the CPU is throttled. In fact, often the thermal design is
not sufficient to cool the CPU at full load and limits can quickly be
reached when a burst in load happens. This will even happen with
technologies like RAPL limitting the long term power consumption of
the package.
Also, these limits are "softer", as Srinivas explains:
"CPU temperature doesn't have to hit max(TjMax) to get these warnings.
OEMs ha[ve] an ability to program a threshold where a thermal interrupt
can be generated. In some systems the offset is 20C+ (Read only value).
In recent systems, there is another offset on top of it which can be
programmed by OS, once some agent can adjust power limits dynamically.
By default this is set to low by the firmware, which I guess the
prime motivation of Benjamin to submit the patch."
So these messages do not usually indicate a hardware issue (e.g.
insufficient cooling). Log them as warnings to avoid confusion about
their severity.
[ bp: Massage commit mesage. ]
Signed-off-by: Benjamin Berg <bberg@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Christian Kellner <ckellner@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20191009155424.249277-1-bberg@redhat.com
Check that the per-cpu cluster mask pointer has been set prior to
clearing a dying cpu's bit. The per-cpu pointer is not set until the
target cpu reaches smp_callin() during CPUHP_BRINGUP_CPU, whereas the
teardown function, x2apic_dead_cpu(), is associated with the earlier
CPUHP_X2APIC_PREPARE. If an error occurs before the cpu is awakened,
e.g. if do_boot_cpu() itself fails, x2apic_dead_cpu() will dereference
the NULL pointer and cause a panic.
smpboot: do_boot_cpu failed(-22) to wakeup CPU#1
BUG: kernel NULL pointer dereference, address: 0000000000000008
RIP: 0010:x2apic_dead_cpu+0x1a/0x30
Call Trace:
cpuhp_invoke_callback+0x9a/0x580
_cpu_up+0x10d/0x140
do_cpu_up+0x69/0xb0
smp_init+0x63/0xa9
kernel_init_freeable+0xd7/0x229
? rest_init+0xa0/0xa0
kernel_init+0xa/0x100
ret_from_fork+0x35/0x40
Fixes: 023a611748 ("x86/apic/x2apic: Simplify cluster management")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20191001205019.5789-1-sean.j.christopherson@intel.com
