License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 08:07:57 -06:00
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# SPDX-License-Identifier: GPL-2.0
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2007-12-16 02:02:48 -07:00
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2015-03-26 08:39:31 -06:00
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ccflags-y += -Iarch/x86/kvm
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2007-12-16 02:02:48 -07:00
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2013-05-14 07:31:02 -06:00
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KVM := ../../../virt/kvm
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2014-11-20 05:45:31 -07:00
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kvm-y += $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o \
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2013-10-30 11:02:17 -06:00
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$(KVM)/eventfd.o $(KVM)/irqchip.o $(KVM)/vfio.o
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2013-05-14 07:31:02 -06:00
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kvm-$(CONFIG_KVM_ASYNC_PF) += $(KVM)/async_pf.o
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2009-05-18 06:16:14 -06:00
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2019-11-21 02:45:07 -07:00
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kvm-y += x86.o emulate.o i8259.o irq.o lapic.o \
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2015-07-03 06:01:34 -06:00
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i8254.o ioapic.o irq_comm.o cpuid.o pmu.o mtrr.o \
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2019-11-21 02:45:07 -07:00
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hyperv.o debugfs.o mmu/mmu.o mmu/page_track.o
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2015-07-03 06:01:34 -06:00
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KVM: VMX: Move VM-Enter + VM-Exit handling to non-inline sub-routines
Transitioning to/from a VMX guest requires KVM to manually save/load
the bulk of CPU state that the guest is allowed to direclty access,
e.g. XSAVE state, CR2, GPRs, etc... For obvious reasons, loading the
guest's GPR snapshot prior to VM-Enter and saving the snapshot after
VM-Exit is done via handcoded assembly. The assembly blob is written
as inline asm so that it can easily access KVM-defined structs that
are used to hold guest state, e.g. moving the blob to a standalone
assembly file would require generating defines for struct offsets.
The other relevant aspect of VMX transitions in KVM is the handling of
VM-Exits. KVM doesn't employ a separate VM-Exit handler per se, but
rather treats the VMX transition as a mega instruction (with many side
effects), i.e. sets the VMCS.HOST_RIP to a label immediately following
VMLAUNCH/VMRESUME. The label is then exposed to C code via a global
variable definition in the inline assembly.
Because of the global variable, KVM takes steps to (attempt to) ensure
only a single instance of the owning C function, e.g. vmx_vcpu_run, is
generated by the compiler. The earliest approach placed the inline
assembly in a separate noinline function[1]. Later, the assembly was
folded back into vmx_vcpu_run() and tagged with __noclone[2][3], which
is still used today.
After moving to __noclone, an edge case was encountered where GCC's
-ftracer optimization resulted in the inline assembly blob being
duplicated. This was "fixed" by explicitly disabling -ftracer in the
__noclone definition[4].
Recently, it was found that disabling -ftracer causes build warnings
for unsuspecting users of __noclone[5], and more importantly for KVM,
prevents the compiler for properly optimizing vmx_vcpu_run()[6]. And
perhaps most importantly of all, it was pointed out that there is no
way to prevent duplication of a function with 100% reliability[7],
i.e. more edge cases may be encountered in the future.
So to summarize, the only way to prevent the compiler from duplicating
the global variable definition is to move the variable out of inline
assembly, which has been suggested several times over[1][7][8].
Resolve the aforementioned issues by moving the VMLAUNCH+VRESUME and
VM-Exit "handler" to standalone assembly sub-routines. Moving only
the core VMX transition codes allows the struct indexing to remain as
inline assembly and also allows the sub-routines to be used by
nested_vmx_check_vmentry_hw(). Reusing the sub-routines has a happy
side-effect of eliminating two VMWRITEs in the nested_early_check path
as there is no longer a need to dynamically change VMCS.HOST_RIP.
Note that callers to vmx_vmenter() must account for the CALL modifying
RSP, e.g. must subtract op-size from RSP when synchronizing RSP with
VMCS.HOST_RSP and "restore" RSP prior to the CALL. There are no great
alternatives to fudging RSP. Saving RSP in vmx_enter() is difficult
because doing so requires a second register (VMWRITE does not provide
an immediate encoding for the VMCS field and KVM supports Hyper-V's
memory-based eVMCS ABI). The other more drastic alternative would be
to use eschew VMCS.HOST_RSP and manually save/load RSP using a per-cpu
variable (which can be encoded as e.g. gs:[imm]). But because a valid
stack is needed at the time of VM-Exit (NMIs aren't blocked and a user
could theoretically insert INT3/INT1ICEBRK at the VM-Exit handler), a
dedicated per-cpu VM-Exit stack would be required. A dedicated stack
isn't difficult to implement, but it would require at least one page
per CPU and knowledge of the stack in the dumpstack routines. And in
most cases there is essentially zero overhead in dynamically updating
VMCS.HOST_RSP, e.g. the VMWRITE can be avoided for all but the first
VMLAUNCH unless nested_early_check=1, which is not a fast path. In
other words, avoiding the VMCS.HOST_RSP by using a dedicated stack
would only make the code marginally less ugly while requiring at least
one page per CPU and forcing the kernel to be aware (and approve) of
the VM-Exit stack shenanigans.
[1] cea15c24ca39 ("KVM: Move KVM context switch into own function")
[2] a3b5ba49a8c5 ("KVM: VMX: add the __noclone attribute to vmx_vcpu_run")
[3] 104f226bfd0a ("KVM: VMX: Fold __vmx_vcpu_run() into vmx_vcpu_run()")
[4] 95272c29378e ("compiler-gcc: disable -ftracer for __noclone functions")
[5] https://lkml.kernel.org/r/20181218140105.ajuiglkpvstt3qxs@treble
[6] https://patchwork.kernel.org/patch/8707981/#21817015
[7] https://lkml.kernel.org/r/ri6y38lo23g.fsf@suse.cz
[8] https://lkml.kernel.org/r/20181218212042.GE25620@tassilo.jf.intel.com
Suggested-by: Andi Kleen <ak@linux.intel.com>
Suggested-by: Martin Jambor <mjambor@suse.cz>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Martin Jambor <mjambor@suse.cz>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-12-20 13:25:17 -07:00
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kvm-intel-y += vmx/vmx.o vmx/vmenter.o vmx/pmu_intel.o vmx/vmcs12.o vmx/evmcs.o vmx/nested.o
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2015-06-19 07:45:05 -06:00
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kvm-amd-y += svm.o pmu_amd.o
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2009-05-18 06:16:14 -06:00
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obj-$(CONFIG_KVM) += kvm.o
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obj-$(CONFIG_KVM_INTEL) += kvm-intel.o
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obj-$(CONFIG_KVM_AMD) += kvm-amd.o
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