Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.
For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.
However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:
----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()
// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch
virtual patch
@ depends on patch @
expression E1, E2;
@@
- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)
@ depends on patch @
expression E;
@@
- ACCESS_ONCE(E)
+ READ_ONCE(E)
----
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We are going to support boot-time switching between 4- and 5-level
paging. For KASAN it means we cannot have different KASAN_SHADOW_OFFSET
for different paging modes: the constant is passed to gcc to generate
code and cannot be changed at runtime.
This patch changes KASAN code to use 0xdffffc0000000000 as shadow offset
for both 4- and 5-level paging.
For 5-level paging it means that shadow memory region is not aligned to
PGD boundary anymore and we have to handle unaligned parts of the region
properly.
In addition, we have to exclude paravirt code from KASAN instrumentation
as we now use set_pgd() before KASAN is fully ready.
[kirill.shutemov@linux.intel.com: clenaup, changelog message]
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@suse.de>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170929140821.37654-4-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We do not have tracepoints for sys_modify_ldt() because we define
it directly instead of using the normal SYSCALL_DEFINEx() macros.
However, there is a reason sys_modify_ldt() does not use the macros:
it has an 'int' return type instead of 'unsigned long'. This is
a bug, but it's a bug cemented in the ABI.
What does this mean? If we return -EINVAL from a function that
returns 'int', we have 0x00000000ffffffea in %rax. But, if we
return -EINVAL from a function returning 'unsigned long', we end
up with 0xffffffffffffffea in %rax, which is wrong.
To work around this and maintain the 'int' behavior while using
the SYSCALL_DEFINEx() macros, so we add a cast to 'unsigned int'
in both implementations of sys_modify_ldt().
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Brian Gerst <brgerst@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20171018172107.1A79C532@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
do_clear_cpu_cap() allocates a bitmap to keep track of disabled feature
dependencies. That bitmap is sized NCAPINTS * BITS_PER_INIT. The possible
'features' which can be handed in are larger than this, because after the
capabilities the bug 'feature' bits occupy another 32bit. Not really
obvious...
So clearing any of the misfeature bits, as 32bit does for the F00F bug,
accesses that bitmap out of bounds thereby corrupting the stack.
Size the bitmap proper and add a sanity check to catch accidental out of
bound access.
Fixes: 0b00de857a ("x86/cpuid: Add generic table for CPUID dependencies")
Reported-by: kernel test robot <xiaolong.ye@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/20171018022023.GA12058@yexl-desktop
Clearing a CPU feature with setup_clear_cpu_cap() clears all features
which depend on it. Expressing feature dependencies in one place is
easier to maintain than keeping functions like
fpu__xstate_clear_all_cpu_caps() up to date.
The features which depend on XSAVE have their dependency expressed in the
dependency table, so its sufficient to clear X86_FEATURE_XSAVE.
Remove the explicit clearing of XSAVE dependent features.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20171013215645.23166-6-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With a followon patch we want to make clearcpuid affect the XSAVE
configuration. But xsave is currently initialized before arguments
are parsed. Move the clearcpuid= parsing into the special
early xsave argument parsing code.
Since clearcpuid= contains a = we need to keep the old __setup
around as a dummy, otherwise it would end up as a environment
variable in init's environment.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20171013215645.23166-4-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Some CPUID features depend on other features. Currently it's
possible to to clear dependent features, but not clear the base features,
which can cause various interesting problems.
This patch implements a generic table to describe dependencies
between CPUID features, to be used by all code that clears
CPUID.
Some subsystems (like XSAVE) had an own implementation of this,
but it's better to do it all in a single place for everyone.
Then clear_cpu_cap and setup_clear_cpu_cap always look up
this table and clear all dependencies too.
This is intended to be a practical table: only for features
that make sense to clear. If someone for example clears FPU,
or other features that are essentially part of the required
base feature set, not much is going to work. Handling
that is right now out of scope. We're only handling
features which can be usefully cleared.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jonathan McDowell <noodles@earth.li>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20171013215645.23166-3-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
free_moved_vector() accesses the per cpu vector array with this_cpu_write()
to clear the vector. The function has two call sites:
1) The vector cleanup IPI
2) The force_complete_move() code path
For #1 this_cpu_write() is correct as it runs on the CPU on which the
vector needs to be freed.
For #2 this_cpu_write() is wrong because the function is called from an
outgoing CPU which is not necessarily the CPU on which the previous vector
needs to be freed. As a result it sets the vector on the outgoing CPU to
NULL, which is pointless as that CPU does not handle interrupts
anymore. What's worse is that it leaves the vector on the previous target
CPU in place which later on triggers the BUG_ON(vector) in the vector
allocation code when the vector gets reused. That's possible because the
bitmap allocator entry of that CPU is freed correctly.
Always use the CPU to which the vector was associated and clear the vector
entry on that CPU. Fixup the tracepoint as well so it tracks on which CPU
the vector gets removed.
Fixes: 69cde0004a ("x86/vector: Use matrix allocator for vector assignment")
Reported-by: Petri Latvala <petri.latvala@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Juergen Gross <jgross@suse.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Yu Chen <yu.c.chen@intel.com>
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1710161614430.1973@nanos
Moving the early IDT setup out of assembly code breaks the boot on first
generation 486 systems.
The reason is that the call of idt_setup_early_handler, which sets up the
early handlers was added after the call to cr4_init_shadow().
cr4_init_shadow() tries to read CR4 which is not available on those
systems. The accessor function uses a extable fixup to handle the resulting
fault. As the IDT is not set up yet, the cr4 read exception causes an
instantaneous reboot for obvious reasons.
Call idt_setup_early_handler() before cr4_init_shadow() so IDT is set up
before the first exception hits.
Fixes: 87e81786b1 ("x86/idt: Move early IDT setup out of 32-bit asm")
Reported-and-tested-by: Matthew Whitehead <whiteheadm@acm.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1710161210290.1973@nanos
Pull x86 fixes from Ingo Molnar:
"A landry list of fixes:
- fix reboot breakage on some PCID-enabled system
- fix crashes/hangs on some PCID-enabled systems
- fix microcode loading on certain older CPUs
- various unwinder fixes
- extend an APIC quirk to more hardware systems and disable APIC
related warning on virtualized systems
- various Hyper-V fixes
- a macro definition robustness fix
- remove jprobes IRQ disabling
- various mem-encryption fixes"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/microcode: Do the family check first
x86/mm: Flush more aggressively in lazy TLB mode
x86/apic: Update TSC_DEADLINE quirk with additional SKX stepping
x86/apic: Silence "FW_BUG TSC_DEADLINE disabled due to Errata" on hypervisors
x86/mm: Disable various instrumentations of mm/mem_encrypt.c and mm/tlb.c
x86/hyperv: Fix hypercalls with extended CPU ranges for TLB flushing
x86/hyperv: Don't use percpu areas for pcpu_flush/pcpu_flush_ex structures
x86/hyperv: Clear vCPU banks between calls to avoid flushing unneeded vCPUs
x86/unwind: Disable unwinder warnings on 32-bit
x86/unwind: Align stack pointer in unwinder dump
x86/unwind: Use MSB for frame pointer encoding on 32-bit
x86/unwind: Fix dereference of untrusted pointer
x86/alternatives: Fix alt_max_short macro to really be a max()
x86/mm/64: Fix reboot interaction with CR4.PCIDE
kprobes/x86: Remove IRQ disabling from jprobe handlers
kprobes/x86: Set up frame pointer in kprobe trampoline
Pull RAS fixes from Ingo Molnar:
"A boot parameter fix, plus a header export fix"
* 'ras-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mce: Hide mca_cfg
RAS/CEC: Use the right length for "cec_disable"
Commit 594a30fb12 ("x86/apic: Silence "FW_BUG TSC_DEADLINE disabled
due to Errata" on CPUs without the feature", 2017-08-30) was also about
silencing the warning on VirtualBox; however, KVM does expose the TSC
deadline timer, and it's virtualized so that it is immune from CPU errata.
Therefore, booting 4.13 with "-cpu Haswell" shows this in the logs:
[ 0.000000] [Firmware Bug]: TSC_DEADLINE disabled due to Errata;
please update microcode to version: 0xb2 (or later)
Even if you had a hypervisor that does _not_ virtualize the TSC deadline
and rather exposes the hardware one, it should be the hypervisors task
to update microcode and possibly hide the flag from CPUID. So just
hide the message when running on _any_ hypervisor, not just those that
do not support the TSC deadline timer.
The older check still makes sense, so keep it.
Fixes: bd9240a18e ("x86/apic: Add TSC_DEADLINE quirk due to errata")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: kvm@vger.kernel.org
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1507630377-54471-1-git-send-email-pbonzini@redhat.com
The core interrupt code can call the affinity setter for inactive
interrupts under certain circumstances.
For inactive intererupts which use managed or reservation mode this is a
pointless exercise as the activation will assign a vector which fits the
destination mask.
Check for this and return w/o going through the vector assignment.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
On x86-32, Tetsuo Handa and Fengguang Wu reported unwinder warnings
like:
WARNING: kernel stack regs at f60bb9c8 in swapper:1 has bad 'bp' value 0ba00000
And also there were some stack dumps with a bunch of unreliable '?'
symbols after an apic_timer_interrupt symbol, meaning the unwinder got
confused when it tried to read the regs.
The cause of those issues is that, with GCC 4.8 (and possibly older),
there are cases where GCC misaligns the stack pointer in a leaf function
for no apparent reason:
c124a388 <acpi_rs_move_data>:
c124a388: 55 push %ebp
c124a389: 89 e5 mov %esp,%ebp
c124a38b: 57 push %edi
c124a38c: 56 push %esi
c124a38d: 89 d6 mov %edx,%esi
c124a38f: 53 push %ebx
c124a390: 31 db xor %ebx,%ebx
c124a392: 83 ec 03 sub $0x3,%esp
...
c124a3e3: 83 c4 03 add $0x3,%esp
c124a3e6: 5b pop %ebx
c124a3e7: 5e pop %esi
c124a3e8: 5f pop %edi
c124a3e9: 5d pop %ebp
c124a3ea: c3 ret
If an interrupt occurs in such a function, the regs on the stack will be
unaligned, which breaks the frame pointer encoding assumption. So on
32-bit, use the MSB instead of the LSB to encode the regs.
This isn't an issue on 64-bit, because interrupts align the stack before
writing to it.
Reported-and-tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-and-tested-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: LKP <lkp@01.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/279a26996a482ca716605c7dbc7f2db9d8d91e81.1507597785.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Trying to reboot via real mode fails with PCID on: long mode cannot
be exited while CR4.PCIDE is set. (No, I have no idea why, but the
SDM and actual CPUs are in agreement here.) The result is a GPF and
a hang instead of a reboot.
I didn't catch this in testing because neither my computer nor my VM
reboots this way. I can trigger it with reboot=bios, though.
Fixes: 660da7c922 ("x86/mm: Enable CR4.PCIDE on supported systems")
Reported-and-tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/f1e7d965998018450a7a70c2823873686a8b21c0.1507524746.git.luto@kernel.org
