The following BUG_ON() crash was reported on QEMU/i386:
kernel BUG at arch/x86/mm/physaddr.c:79!
Call Trace:
phys_mem_access_prot_allowed
mmap_mem
? mmap_region
mmap_region
do_mmap
vm_mmap_pgoff
SyS_mmap_pgoff
do_int80_syscall_32
entry_INT80_32
after commit:
edfe63ec97 ("x86/mtrr: Fix Xorg crashes in Qemu sessions")
PAT is now set to disabled state when MTRRs are disabled.
Thus, reactivating the __pa(high_memory) check in
phys_mem_access_prot_allowed().
When CONFIG_DEBUG_VIRTUAL is set, __pa() calls __phys_addr(),
which in turn calls slow_virt_to_phys() for 'high_memory'.
Because 'high_memory' is set to (the max direct mapped virt
addr + 1), it is not a valid virtual address. Hence,
slow_virt_to_phys() returns 0 and hit the BUG_ON. Using
__pa_nodebug() instead of __pa() will fix this BUG_ON.
However, this code block, originally written for Pentiums and
earlier, is no longer adequate since a 32-bit Xen guest has
MTRRs disabled and supports ZONE_HIGHMEM. In this setup,
this code sets UC attribute for accessing RAM in high memory
range.
Delete this code block as it has been unused for a long time.
Reported-by: kernel test robot <ying.huang@linux.intel.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1460403360-25441-1-git-send-email-toshi.kani@hpe.com
Link: https://lkml.org/lkml/2016/4/1/608
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When we loop over all queued machine check error records to pass them
to the registered notifiers we use llist_for_each_entry(). But the loop
calls gen_pool_free() for the entry in the body of the loop - and then
the iterator looks at node->next after the free.
Use llist_for_each_entry_safe() instead.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org>
Cc: Gong Chen <gong.chen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/0205920@agluck-desk.sc.intel.com
Link: http://lkml.kernel.org/r/1459929916-12852-4-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reported-by: David Smith <dsmith@redhat.com>
Tested-by: David Smith <dsmith@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.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/20160407204359.GA3720@lst.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Allowing user code to map the HPET is problematic. HPET
implementations are notoriously buggy, and there are probably many
machines on which even MMIO reads from bogus HPET addresses are
problematic.
We have a report that the Dell Precision M2800 with:
ACPI: HPET 0x00000000C8FE6238 000038 (v01 DELL CBX3 01072009 AMI. 00000005)
is either so slow when accessing the HPET or actually hangs in some
regard, causing soft lockups to be reported if users do unexpected
things to the HPET.
The vclock HPET code has also always been a questionable speedup.
Accessing an HPET is exceedingly slow (on the order of several
microseconds), so the added overhead in requiring a syscall to read
the HPET is a small fraction of the total code of accessing it.
To avoid future problems, let's just delete the code entirely.
In the long run, this could actually be a speedup. Waiman Long as a
patch to optimize the case where multiple CPUs contend for the HPET,
but that won't help unless all the accesses are mediated by the
kernel.
Reported-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Waiman Long <Waiman.Long@hpe.com>
Cc: Waiman Long <waiman.long@hpe.com>
Link: http://lkml.kernel.org/r/d2f90bba98db9905041cff294646d290d378f67a.1460074438.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
... so that it doesn't appear in objdump output.
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rudolf Marek <r.marek@assembler.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/b9c532a0e5f8d56dede2bd59767d40024d5a75e2.1460075211.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Erratum 88 affects old AMD K8s, where a SWAPGS fails to cause an input
dependency on GS. Therefore, we need to MFENCE before it.
But that MFENCE is expensive and unnecessary on the remaining x86 CPUs
out there so patch it out on the CPUs which don't require it.
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rudolf Marek <r.marek@assembler.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/aec6b2df1bfc56101d4e9e2e5d5d570bf41663c6.1460075211.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It was in detect_nopl(), which was either a mistake by me or some kind
of mis-merge.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rudolf Marek <r.marek@assembler.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: ff236456f072 ("x86/cpu: Move X86_BUG_ESPFIX initialization to generic_identify")
Link: http://lkml.kernel.org/r/0949337f13660461edca08ab67d1a841441289c9.1460075211.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The old code was incomprehensible and was buggy on AMD CPUs.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rudolf Marek <r.marek@assembler.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/5f6bde874c6fe6831c6711b5b1522a238ba035b4.1460075211.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
AMD and Intel do different things when writing zero to a segment
selector. Since neither vendor documents the behavior well and it's
easy to test the behavior, try nulling fs to see what happens.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rudolf Marek <r.marek@assembler.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/61588ba0e0df35beafd363dc8b68a4c5878ef095.1460075211.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
ARCH_GET_FS and ARCH_GET_GS attempted to figure out the fsbase and
gsbase respectively from saved thread state. This was wrong: fsbase
and gsbase live in registers while a thread is running, not in
memory.
For reasons I can't fathom, the fsbase and gsbase code were
different. Since neither was correct, I didn't try to figure out
what the point of the difference was.
Change it to simply read the MSRs.
The code for reading the base for a remote thread is also completely
wrong if the target thread uses its own descriptors (which is the case
for all 32-bit threaded programs), but fixing that is a different
story.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rudolf Marek <r.marek@assembler.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/c6e7b507c72ca3bdbf6c7a8a3ceaa0334e873bd9.1460075211.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The 0-day build robot by Fengguang Wu reported a build failure:
arch/x86/events//intel/cstate.c: In function 'cstate_pmu_init':
arch/x86/events//intel/cstate.c:680:6: error: 'cpu_has_hypervisor' undeclared (first use in this function)
... which was caused by a merge mistake I made when applying
the following patch:
0c9f3536cc ("x86/cpufeature: Remove cpu_has_hypervisor")
apply the missing hunk as well.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Cc: David Kershner <david.kershner@unisys.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: sparmaintainer@unisys.com
Cc: virtualization@lists.linux-foundation.org
Link: http://lkml.kernel.org/r/1459266123-21878-3-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Use static_cpu_has() in __flush_tlb_all() due to the time-sensitivity of
this one.
Signed-off-by: Borislav Petkov <bp@suse.de>
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/1459266123-21878-10-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
... before assigning local vars. Kill out label too and simplify.
No functionality change.
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
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/1458130769-24963-1-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The 32-bit x86 assembler in binutils 2.26 will generate R_386_GOT32X
relocation to get the symbol address in PIC. When the compressed x86
kernel isn't built as PIC, the linker optimizes R_386_GOT32X relocations
to their fixed symbol addresses. However, when the compressed x86
kernel is loaded at a different address, it leads to the following
load failure:
Failed to allocate space for phdrs
during the decompression stage.
If the compressed x86 kernel is relocatable at run-time, it should be
compiled with -fPIE, instead of -fPIC, if possible and should be built as
Position Independent Executable (PIE) so that linker won't optimize
R_386_GOT32X relocation to its fixed symbol address.
Older linkers generate R_386_32 relocations against locally defined
symbols, _bss, _ebss, _got and _egot, in PIE. It isn't wrong, just less
optimal than R_386_RELATIVE. But the x86 kernel fails to properly handle
R_386_32 relocations when relocating the kernel. To generate
R_386_RELATIVE relocations, we mark _bss, _ebss, _got and _egot as
hidden in both 32-bit and 64-bit x86 kernels.
To build a 64-bit compressed x86 kernel as PIE, we need to disable the
relocation overflow check to avoid relocation overflow errors. We do
this with a new linker command-line option, -z noreloc-overflow, which
got added recently:
commit 4c10bbaa0912742322f10d9d5bb630ba4e15dfa7
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Tue Mar 15 11:07:06 2016 -0700
Add -z noreloc-overflow option to x86-64 ld
Add -z noreloc-overflow command-line option to the x86-64 ELF linker to
disable relocation overflow check. This can be used to avoid relocation
overflow check if there will be no dynamic relocation overflow at
run-time.
The 64-bit compressed x86 kernel is built as PIE only if the linker supports
-z noreloc-overflow. So far 64-bit relocatable compressed x86 kernel
boots fine even when it is built as a normal executable.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
[ Edited the changelog and comments. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Xen supports PAT without MTRRs for its guests. In order to
enable WC attribute, it was necessary for xen_start_kernel()
to call pat_init_cache_modes() to update PAT table before
starting guest kernel.
Now that the kernel initializes PAT table to the BIOS handoff
state when MTRR is disabled, this Xen-specific PAT init code
is no longer necessary. Delete it from xen_start_kernel().
Also change __init_cache_modes() to a static function since
PAT table should not be tweaked by other modules.
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: elliott@hpe.com
Cc: paul.gortmaker@windriver.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1458769323-24491-7-git-send-email-toshi.kani@hpe.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
get_mtrr_state() calls pat_init() on BSP even if MTRR is disabled.
This results in calling pat_init() on BSP only since APs do not call
pat_init() when MTRR is disabled. This inconsistency between BSP
and APs leads to undefined behavior.
Make BSP's calling condition to pat_init() consistent with AP's,
mtrr_ap_init() and mtrr_aps_init().
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: elliott@hpe.com
Cc: konrad.wilk@oracle.com
Cc: paul.gortmaker@windriver.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1458769323-24491-6-git-send-email-toshi.kani@hpe.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
A Xorg failure on qemu32 was reported as a regression [1] caused by
commit 9cd25aac1f ("x86/mm/pat: Emulate PAT when it is disabled").
This patch fixes the Xorg crash.
Negative effects of this regression were the following two failures [2]
in Xorg on QEMU with QEMU CPU model "qemu32" (-cpu qemu32), which were
triggered by the fact that its virtual CPU does not support MTRRs.
#1. copy_process() failed in the check in reserve_pfn_range()
copy_process
copy_mm
dup_mm
dup_mmap
copy_page_range
track_pfn_copy
reserve_pfn_range
A WC map request was tracked as WC in memtype, which set a PTE as
UC (pgprot) per __cachemode2pte_tbl[]. This led to this error in
reserve_pfn_range() called from track_pfn_copy(), which obtained
a pgprot from a PTE. It converts pgprot to page_cache_mode, which
does not necessarily result in the original page_cache_mode since
__cachemode2pte_tbl[] redirects multiple types to UC.
#2. error path in copy_process() then hit WARN_ON_ONCE in
untrack_pfn().
x86/PAT: Xorg:509 map pfn expected mapping type uncached-
minus for [mem 0xfd000000-0xfdffffff], got write-combining
Call Trace:
dump_stack
warn_slowpath_common
? untrack_pfn
? untrack_pfn
warn_slowpath_null
untrack_pfn
? __kunmap_atomic
unmap_single_vma
? pagevec_move_tail_fn
unmap_vmas
exit_mmap
mmput
copy_process.part.47
_do_fork
SyS_clone
do_syscall_32_irqs_on
entry_INT80_32
These negative effects are caused by two separate bugs, but they
can be addressed in separate patches. Fixing the pat_init() issue
described below addresses the root cause, and avoids Xorg to hit
these cases.
When the CPU does not support MTRRs, MTRR does not call pat_init(),
which leaves PAT enabled without initializing PAT. This pat_init()
issue is a long-standing issue, but manifested as issue #1 (and then
hit issue #2) with the above-mentioned commit because the memtype
now tracks cache attribute with 'page_cache_mode'.
This pat_init() issue existed before the commit, but we used pgprot
in memtype. Hence, we did not have issue #1 before. But WC request
resulted in WT in effect because WC pgrot is actually WT when PAT
is not initialized. This is not how it was designed to work. When
PAT is set to disable properly, WC is converted to UC. The use of
WT can result in a system crash if the target range does not support
WT. Fortunately, nobody ran into such issue before.
To fix this pat_init() issue, PAT code has been enhanced to provide
pat_disable() interface. Call this interface when MTRRs are disabled.
By setting PAT to disable properly, PAT bypasses the memtype check,
and avoids issue #1.
[1]: https://lkml.org/lkml/2016/3/3/828
[2]: https://lkml.org/lkml/2016/3/4/775
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: elliott@hpe.com
Cc: konrad.wilk@oracle.com
Cc: paul.gortmaker@windriver.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1458769323-24491-5-git-send-email-toshi.kani@hpe.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Borislav Petkov suggested:
> Please use on init paths boot_cpu_has(X86_FEATURE_PAT) and on fast
> paths static_cpu_has(X86_FEATURE_PAT). No more of that cpu_has_XXX
> ugliness.
Replace the use of cpu_has_pat on init paths with boot_cpu_has().
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Elliott <elliott@hpe.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: konrad.wilk@oracle.com
Cc: paul.gortmaker@windriver.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1458769323-24491-4-git-send-email-toshi.kani@hpe.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In preparation for fixing a regression caused by:
9cd25aac1f ("x86/mm/pat: Emulate PAT when it is disabled")
... PAT needs to provide an interface that prevents the OS from
initializing the PAT MSR.
PAT MSR initialization must be done on all CPUs using the specific
sequence of operations defined in the Intel SDM. This requires MTRRs
to be enabled since pat_init() is called as part of MTRR init
from mtrr_rendezvous_handler().
Make pat_disable() as the interface that prevents the OS from
initializing the PAT MSR. MTRR will call this interface when it
cannot provide the SDM-defined sequence to initialize PAT.
This also assures that pat_disable() called from pat_bsp_init()
will set the PAT table properly when CPU does not support PAT.
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Elliott <elliott@hpe.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: konrad.wilk@oracle.com
Cc: paul.gortmaker@windriver.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1458769323-24491-3-git-send-email-toshi.kani@hpe.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In preparation for fixing a regression caused by:
9cd25aac1f ("x86/mm/pat: Emulate PAT when it is disabled")'
... PAT needs to support a case that PAT MSR is initialized with a
non-default value.
When pat_init() is called and PAT is disabled, it initializes the
PAT table with the BIOS default value. Xen, however, sets PAT MSR
with a non-default value to enable WC. This causes inconsistency
between the PAT table and PAT MSR when PAT is set to disable on Xen.
Change pat_init() to handle the PAT disable cases properly. Add
init_cache_modes() to handle two cases when PAT is set to disable.
1. CPU supports PAT: Set PAT table to be consistent with PAT MSR.
2. CPU does not support PAT: Set PAT table to be consistent with
PWT and PCD bits in a PTE.
Note, __init_cache_modes(), renamed from pat_init_cache_modes(),
will be changed to a static function in a later patch.
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: elliott@hpe.com
Cc: konrad.wilk@oracle.com
Cc: paul.gortmaker@windriver.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1458769323-24491-2-git-send-email-toshi.kani@hpe.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The list of CPU model specific registers contains two copies of TDP
registers, remove the one, which is out of numerical order in the
list.
Fixes: 6a35fc2d6c ("cpufreq: intel_pstate: get P1 from TAR when available")
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Cc: Len Brown <len.brown@intel.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Kristen Carlson
Accardi <kristen@linux.intel.com>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: http://lkml.kernel.org/r/1459018020-24577-1-git-send-email-vladimir_zapolskiy@mentor.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Avoid allocating the AMD NB event constraints data structure when not
needed. This gets rid of x86_max_cores usage and avoids allocating
this on AMD Core Perfctr supporting hardware (which has separate MSRs
for NB events).
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: aherrmann@suse.com
Cc: Rui Huang <ray.huang@amd.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: jencce.kernel@gmail.com
Link: http://lkml.kernel.org/r/20160320124629.GY6375@twins.programming.kicks-ass.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
It turns out AMD gets x86_max_cores wrong when there are compute
units.
The issue is that Linux assumes:
nr_logical_cpus = nr_cores * nr_siblings
But AMD reports its CU unit as 2 cores, but then sets num_smp_siblings
to 2 as well.
Boris: fixup ras/mce_amd_inj.c too, to compute the Node Base Core
properly, according to the new nomenclature.
Fixes: 1f12e32f4c ("x86/topology: Create logical package id")
Reported-by: Xiong Zhou <jencce.kernel@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andreas Herrmann <aherrmann@suse.com>
Cc: Andy Lutomirski <luto@kernel.org>
Link: http://lkml.kernel.org/r/20160317095220.GO6344@twins.programming.kicks-ass.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Implement the stack depot and provide CONFIG_STACKDEPOT. Stack depot
will allow KASAN store allocation/deallocation stack traces for memory
chunks. The stack traces are stored in a hash table and referenced by
handles which reside in the kasan_alloc_meta and kasan_free_meta
structures in the allocated memory chunks.
IRQ stack traces are cut below the IRQ entry point to avoid unnecessary
duplication.
Right now stackdepot support is only enabled in SLAB allocator. Once
KASAN features in SLAB are on par with those in SLUB we can switch SLUB
to stackdepot as well, thus removing the dependency on SLUB stack
bookkeeping, which wastes a lot of memory.
This patch is based on the "mm: kasan: stack depots" patch originally
prepared by Dmitry Chernenkov.
Joonsoo has said that he plans to reuse the stackdepot code for the
mm/page_owner.c debugging facility.
[akpm@linux-foundation.org: s/depot_stack_handle/depot_stack_handle_t]
[aryabinin@virtuozzo.com: comment style fixes]
Signed-off-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
KASAN needs to know whether the allocation happens in an IRQ handler.
This lets us strip everything below the IRQ entry point to reduce the
number of unique stack traces needed to be stored.
Move the definition of __irq_entry to <linux/interrupt.h> so that the
users don't need to pull in <linux/ftrace.h>. Also introduce the
__softirq_entry macro which is similar to __irq_entry, but puts the
corresponding functions to the .softirqentry.text section.
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some visible changes:
A new flag was added to distinguish traces done in NMI context.
Preempt tracer now shows functions where preemption is disabled but
interrupts are still enabled.
Other notes:
Updates were done to function tracing to allow better performance
with perf.
Infrastructure code has been added to allow for a new histogram
feature for recording live trace event histograms that can be
configured by simple user commands. The feature itself was just
finished, but needs a round in linux-next before being pulled.
This only includes some infrastructure changes that will be needed.
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Merge tag 'trace-v4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"Nothing major this round. Mostly small clean ups and fixes.
Some visible changes:
- A new flag was added to distinguish traces done in NMI context.
- Preempt tracer now shows functions where preemption is disabled but
interrupts are still enabled.
Other notes:
- Updates were done to function tracing to allow better performance
with perf.
- Infrastructure code has been added to allow for a new histogram
feature for recording live trace event histograms that can be
configured by simple user commands. The feature itself was just
finished, but needs a round in linux-next before being pulled.
This only includes some infrastructure changes that will be needed"
* tag 'trace-v4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (22 commits)
tracing: Record and show NMI state
tracing: Fix trace_printk() to print when not using bprintk()
tracing: Remove redundant reset per-CPU buff in irqsoff tracer
x86: ftrace: Fix the misleading comment for arch/x86/kernel/ftrace.c
tracing: Fix crash from reading trace_pipe with sendfile
tracing: Have preempt(irqs)off trace preempt disabled functions
tracing: Fix return while holding a lock in register_tracer()
ftrace: Use kasprintf() in ftrace_profile_tracefs()
ftrace: Update dynamic ftrace calls only if necessary
ftrace: Make ftrace_hash_rec_enable return update bool
tracing: Fix typoes in code comment and printk in trace_nop.c
tracing, writeback: Replace cgroup path to cgroup ino
tracing: Use flags instead of bool in trigger structure
tracing: Add an unreg_all() callback to trigger commands
tracing: Add needs_rec flag to event triggers
tracing: Add a per-event-trigger 'paused' field
tracing: Add get_syscall_name()
tracing: Add event record param to trigger_ops.func()
tracing: Make event trigger functions available
tracing: Make ftrace_event_field checking functions available
...
Pull perf fixes from Ingo Molnar:
"This tree contains various perf fixes on the kernel side, plus three
hw/event-enablement late additions:
- Intel Memory Bandwidth Monitoring events and handling
- the AMD Accumulated Power Mechanism reporting facility
- more IOMMU events
... and a final round of perf tooling updates/fixes"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits)
perf llvm: Use strerror_r instead of the thread unsafe strerror one
perf llvm: Use realpath to canonicalize paths
perf tools: Unexport some methods unused outside strbuf.c
perf probe: No need to use formatting strbuf method
perf help: Use asprintf instead of adhoc equivalents
perf tools: Remove unused perf_pathdup, xstrdup functions
perf tools: Do not include stringify.h from the kernel sources
tools include: Copy linux/stringify.h from the kernel
tools lib traceevent: Remove redundant CPU output
perf tools: Remove needless 'extern' from function prototypes
perf tools: Simplify die() mechanism
perf tools: Remove unused DIE_IF macro
perf script: Remove lots of unused arguments
perf thread: Rename perf_event__preprocess_sample_addr to thread__resolve
perf machine: Rename perf_event__preprocess_sample to machine__resolve
perf tools: Add cpumode to struct perf_sample
perf tests: Forward the perf_sample in the dwarf unwind test
perf tools: Remove misplaced __maybe_unused
perf list: Fix documentation of :ppp
perf bench numa: Fix assertion for nodes bitfield
...
After e76b027 ("x86,vdso: Use LSL unconditionally for vgetcpu")
native_read_tscp() is unused in the kernel. The function can be removed like
native_read_tsc() was.
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1458687968-9106-1-git-send-email-prarit@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Merge third patch-bomb from Andrew Morton:
- more ocfs2 changes
- a few hotfixes
- Andy's compat cleanups
- misc fixes to fatfs, ptrace, coredump, cpumask, creds, eventfd,
panic, ipmi, kgdb, profile, kfifo, ubsan, etc.
- many rapidio updates: fixes, new drivers.
- kcov: kernel code coverage feature. Like gcov, but not
"prohibitively expensive".
- extable code consolidation for various archs
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (81 commits)
ia64/extable: use generic search and sort routines
x86/extable: use generic search and sort routines
s390/extable: use generic search and sort routines
alpha/extable: use generic search and sort routines
kernel/...: convert pr_warning to pr_warn
drivers: dma-coherent: use memset_io for DMA_MEMORY_IO mappings
drivers: dma-coherent: use MEMREMAP_WC for DMA_MEMORY_MAP
memremap: add MEMREMAP_WC flag
memremap: don't modify flags
kernel/signal.c: add compile-time check for __ARCH_SI_PREAMBLE_SIZE
mm/mprotect.c: don't imply PROT_EXEC on non-exec fs
ipc/sem: make semctl setting sempid consistent
ubsan: fix tree-wide -Wmaybe-uninitialized false positives
kfifo: fix sparse complaints
scripts/gdb: account for changes in module data structure
scripts/gdb: add cmdline reader command
scripts/gdb: add version command
kernel: add kcov code coverage
profile: hide unused functions when !CONFIG_PROC_FS
hpwdt: use nmi_panic() when kernel panics in NMI handler
...
* Miscellaneous bugfixes for ARM KVM
* Cleanup of memory barrier and removal of redundant barriers
* x86 fixes: page tracking oops, support for old buggy KVM nested on 4.5
* Support for protection keys in guests
* Lockdep fix
* Another conversion to simple wait queues and raw spinlocks,
backported from PREEMPT_RT
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull more KVM updates from Paolo Bonzini:
"Second round of KVM changes for 4.6:
- build fixes for PPC KVM
- miscellaneous bugfixes for ARM KVM
- cleanup of memory barrier and removal of redundant barriers
- x86 fixes: page tracking oops, support for old buggy KVM nested on 4.5
- support for protection keys in guests
- lockdep fix
- another conversion to simple wait queues and raw spinlocks,
backported from PREEMPT_RT"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (27 commits)
KVM: page_track: fix access to NULL slot
KVM: PPC: do not compile in vfio.o unconditionally
kvm, rt: change async pagefault code locking for PREEMPT_RT
KVM/PPC: update the comment of memory barrier in the kvmppc_prepare_to_enter()
KVM/x86: update the comment of memory barrier in the vcpu_enter_guest()
KVM: Replace smp_mb() with smp_load_acquire() in the kvm_flush_remote_tlbs()
KVM/x86: Call smp_wmb() before increasing tlbs_dirty
KVM: Replace smp_mb() with smp_mb_after_atomic() in the kvm_make_all_cpus_request()
KVM/x86: Replace smp_mb() with smp_store_mb/release() in the walk_shadow_page_lockless_begin/end()
KVM: Remove redundant smp_mb() in the kvm_mmu_commit_zap_page()
KVM, pkeys: expose CPUID/CR4 to guest
KVM, pkeys: add pkeys support for permission_fault
KVM, pkeys: introduce pkru_mask to cache conditions
KVM, pkeys: save/restore PKRU when guest/host switches
x86: pkey: introduce write_pkru() for KVM
KVM, pkeys: add pkeys support for xsave state
KVM, pkeys: disable pkeys for guests in non-paging mode
KVM: x86: remove magic number with enum cpuid_leafs
KVM: MMU: return page fault error code from permission_fault
KVM: fix spin_lock_init order on x86
...
Replace the arch specific versions of search_extable() and
sort_extable() with calls to the generic ones, which now support
relative exception tables as well.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kcov provides code coverage collection for coverage-guided fuzzing
(randomized testing). Coverage-guided fuzzing is a testing technique
that uses coverage feedback to determine new interesting inputs to a
system. A notable user-space example is AFL
(http://lcamtuf.coredump.cx/afl/). However, this technique is not
widely used for kernel testing due to missing compiler and kernel
support.
kcov does not aim to collect as much coverage as possible. It aims to
collect more or less stable coverage that is function of syscall inputs.
To achieve this goal it does not collect coverage in soft/hard
interrupts and instrumentation of some inherently non-deterministic or
non-interesting parts of kernel is disbled (e.g. scheduler, locking).
Currently there is a single coverage collection mode (tracing), but the
API anticipates additional collection modes. Initially I also
implemented a second mode which exposes coverage in a fixed-size hash
table of counters (what Quentin used in his original patch). I've
dropped the second mode for simplicity.
This patch adds the necessary support on kernel side. The complimentary
compiler support was added in gcc revision 231296.
We've used this support to build syzkaller system call fuzzer, which has
found 90 kernel bugs in just 2 months:
https://github.com/google/syzkaller/wiki/Found-Bugs
We've also found 30+ bugs in our internal systems with syzkaller.
Another (yet unexplored) direction where kcov coverage would greatly
help is more traditional "blob mutation". For example, mounting a
random blob as a filesystem, or receiving a random blob over wire.
Why not gcov. Typical fuzzing loop looks as follows: (1) reset
coverage, (2) execute a bit of code, (3) collect coverage, repeat. A
typical coverage can be just a dozen of basic blocks (e.g. an invalid
input). In such context gcov becomes prohibitively expensive as
reset/collect coverage steps depend on total number of basic
blocks/edges in program (in case of kernel it is about 2M). Cost of
kcov depends only on number of executed basic blocks/edges. On top of
that, kernel requires per-thread coverage because there are always
background threads and unrelated processes that also produce coverage.
With inlined gcov instrumentation per-thread coverage is not possible.
kcov exposes kernel PCs and control flow to user-space which is
insecure. But debugfs should not be mapped as user accessible.
Based on a patch by Quentin Casasnovas.
[akpm@linux-foundation.org: make task_struct.kcov_mode have type `enum kcov_mode']
[akpm@linux-foundation.org: unbreak allmodconfig]
[akpm@linux-foundation.org: follow x86 Makefile layout standards]
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: syzkaller <syzkaller@googlegroups.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tavis Ormandy <taviso@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Kees Cook <keescook@google.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: David Drysdale <drysdale@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
x86's is_compat_task always checked the current syscall type, not the
task type. It has no non-arch users any more, so just remove it to
avoid confusion.
On x86, nothing should really be checking the task ABI. There are
legitimate users for the syscall ABI and for the mm ABI.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>