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git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull stackleak gcc plugin from Kees Cook:
"Please pull this new GCC plugin, stackleak, for v4.20-rc1. This plugin
was ported from grsecurity by Alexander Popov. It provides efficient
stack content poisoning at syscall exit. This creates a defense
against at least two classes of flaws:
- Uninitialized stack usage. (We continue to work on improving the
compiler to do this in other ways: e.g. unconditional zero init was
proposed to GCC and Clang, and more plugin work has started too).
- Stack content exposure. By greatly reducing the lifetime of valid
stack contents, exposures via either direct read bugs or unknown
cache side-channels become much more difficult to exploit. This
complements the existing buddy and heap poisoning options, but
provides the coverage for stacks.
The x86 hooks are included in this series (which have been reviewed by
Ingo, Dave Hansen, and Thomas Gleixner). The arm64 hooks have already
been merged through the arm64 tree (written by Laura Abbott and
reviewed by Mark Rutland and Will Deacon).
With VLAs having been removed this release, there is no need for
alloca() protection, so it has been removed from the plugin"
* tag 'stackleak-v4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
arm64: Drop unneeded stackleak_check_alloca()
stackleak: Allow runtime disabling of kernel stack erasing
doc: self-protection: Add information about STACKLEAK feature
fs/proc: Show STACKLEAK metrics in the /proc file system
lkdtm: Add a test for STACKLEAK
gcc-plugins: Add STACKLEAK plugin for tracking the kernel stack
x86/entry: Add STACKLEAK erasing the kernel stack at the end of syscalls
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"The biggest change here is the updates to kprobes
Back in January I posted patches to create function based events.
These were the events that you suggested I make to allow developers to
easily create events in code where no trace event exists. After
posting those changes for review, it was suggested that we implement
this instead with kprobes.
The problem with kprobes is that the interface is too complex and
needs to be simplified. Masami Hiramatsu posted patches in March and
I've been playing with them a bit. There's been a bit of clean up in
the kprobe code that was inspired by the function based event patches,
and a couple of enhancements to the kprobe event interface.
- If the arch supports it (we added support for x86), you can place a
kprobe event at the start of a function and use $arg1, $arg2, etc
to reference the arguments of a function. (Before you needed to
know what register or where on the stack the argument was).
- The second is a way to see array of events. For example, if you
reference a mac address, you can add:
echo 'p:mac ip_rcv perm_addr=+574($arg2):x8[6]' > kprobe_events
And this will produce:
mac: (ip_rcv+0x0/0x140) perm_addr={0x52,0x54,0x0,0xc0,0x76,0xec}
Other changes include
- Exporting trace_dump_stack to modules
- Have the stack tracer trace the entire stack (stop trying to remove
tracing itself, as we keep removing too much).
- Added support for SDT in uprobes"
[ SDT - "Statically Defined Tracing" are userspace markers for tracing.
Let's not use random TLA's in explanations unless they are fairly
well-established as generic (at least for kernel people) - Linus ]
* tag 'trace-v4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (24 commits)
tracing: Have stack tracer trace full stack
tracing: Export trace_dump_stack to modules
tracing: probeevent: Fix uninitialized used of offset in parse args
tracing/kprobes: Allow kprobe-events to record module symbol
tracing/kprobes: Check the probe on unloaded module correctly
tracing/uprobes: Fix to return -EFAULT if copy_from_user failed
tracing: probeevent: Add $argN for accessing function args
x86: ptrace: Add function argument access API
tracing: probeevent: Add array type support
tracing: probeevent: Add symbol type
tracing: probeevent: Unify fetch_insn processing common part
tracing: probeevent: Append traceprobe_ for exported function
tracing: probeevent: Return consumed bytes of dynamic area
tracing: probeevent: Unify fetch type tables
tracing: probeevent: Introduce new argument fetching code
tracing: probeevent: Remove NOKPROBE_SYMBOL from print functions
tracing: probeevent: Cleanup argument field definition
tracing: probeevent: Cleanup print argument functions
trace_uprobe: support reference counter in fd-based uprobe
perf probe: Support SDT markers having reference counter (semaphore)
...
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Add regs_get_argument() which returns N th argument of the
function call.
Note that this chooses most probably assignment, in some case
it can be incorrect (e.g. passing data structure or floating
point etc.)
This is expected to be called from kprobes or ftrace with regs
where the top of stack is the return address.
Link: http://lkml.kernel.org/r/152465885737.26224.2822487520472783854.stgit@devbox
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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To reduce the size taken up by absolute references in jump label
entries themselves and the associated relocation records in the
.init segment, add support for emitting them as relative references
instead.
Note that this requires some extra care in the sorting routine, given
that the offsets change when entries are moved around in the jump_entry
table.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Jessica Yu <jeyu@kernel.org>
Link: https://lkml.kernel.org/r/20180919065144.25010-3-ard.biesheuvel@linaro.org
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The STACKLEAK feature (initially developed by PaX Team) has the following
benefits:
1. Reduces the information that can be revealed through kernel stack leak
bugs. The idea of erasing the thread stack at the end of syscalls is
similar to CONFIG_PAGE_POISONING and memzero_explicit() in kernel
crypto, which all comply with FDP_RIP.2 (Full Residual Information
Protection) of the Common Criteria standard.
2. Blocks some uninitialized stack variable attacks (e.g. CVE-2017-17712,
CVE-2010-2963). That kind of bugs should be killed by improving C
compilers in future, which might take a long time.
This commit introduces the code filling the used part of the kernel
stack with a poison value before returning to userspace. Full
STACKLEAK feature also contains the gcc plugin which comes in a
separate commit.
The STACKLEAK feature is ported from grsecurity/PaX. More information at:
https://grsecurity.net/
https://pax.grsecurity.net/
This code is modified from Brad Spengler/PaX Team's code in the last
public patch of grsecurity/PaX based on our understanding of the code.
Changes or omissions from the original code are ours and don't reflect
the original grsecurity/PaX code.
Performance impact:
Hardware: Intel Core i7-4770, 16 GB RAM
Test #1: building the Linux kernel on a single core
0.91% slowdown
Test #2: hackbench -s 4096 -l 2000 -g 15 -f 25 -P
4.2% slowdown
So the STACKLEAK description in Kconfig includes: "The tradeoff is the
performance impact: on a single CPU system kernel compilation sees a 1%
slowdown, other systems and workloads may vary and you are advised to
test this feature on your expected workload before deploying it".
Signed-off-by: Alexander Popov <alex.popov@linux.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
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Merge fixes for missing TLB shootdowns.
This fixes a couple of cases that involved us possibly freeing page
table structures before the required TLB shootdown had been done.
There are a few cleanup patches to make the code easier to follow, and
to avoid some of the more problematic cases entirely when not necessary.
To make this easier for backports, it undoes the recent lazy TLB
patches, because the cleanups and fixes are more important, and Rik is
ok with re-doing them later when things have calmed down.
The missing TLB flush was only delayed, and the wrong ordering only
happened under memory pressure (and in theory under a couple of other
fairly theoretical situations), so this may have been all very unlikely
to have hit people in practice.
But getting the TLB shootdown wrong is _so_ hard to debug and see that I
consider this a crticial fix.
Many thanks to Jann Horn for having debugged this.
* tlb-fixes:
x86/mm: Only use tlb_remove_table() for paravirt
mm: mmu_notifier fix for tlb_end_vma
mm/tlb, x86/mm: Support invalidating TLB caches for RCU_TABLE_FREE
mm/tlb: Remove tlb_remove_table() non-concurrent condition
mm: move tlb_table_flush to tlb_flush_mmu_free
x86/mm/tlb: Revert the recent lazy TLB patches
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git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux
Pull MIPS fixes from Paul Burton:
- Fix microMIPS build failures by adding a .insn directive to the
barrier_before_unreachable() asm statement in order to convince the
toolchain that the asm statement is a valid branch target rather
than a bogus attempt to switch ISA.
- Clean up our declarations of TLB functions that we overwrite with
generated code in order to prevent the compiler making assumptions
about alignment that cause microMIPS kernels built with GCC 7 &
above to die early during boot.
- Fix up a regression for MIPS32 kernels which slipped into the main
MIPS pull for 4.19, causing CONFIG_32BIT=y kernels to contain
inappropriate MIPS64 instructions.
- Extend our existing workaround for MIPSr6 builds that end up using
the __multi3 intrinsic to GCC 7 & below, rather than just GCC 7.
* tag 'mips_4.19_2' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
MIPS: lib: Provide MIPS64r6 __multi3() for GCC < 7
MIPS: Workaround GCC __builtin_unreachable reordering bug
compiler.h: Allow arch-specific asm/compiler.h
MIPS: Avoid move psuedo-instruction whilst using MIPS_ISA_LEVEL
MIPS: Consistently declare TLB functions
MIPS: Export tlbmiss_handler_setup_pgd near its definition
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Jann reported that x86 was missing required TLB invalidates when he
hit the !*batch slow path in tlb_remove_table().
This is indeed the case; RCU_TABLE_FREE does not provide TLB (cache)
invalidates, the PowerPC-hash where this code originated and the
Sparc-hash where this was subsequently used did not need that. ARM
which later used this put an explicit TLB invalidate in their
__p*_free_tlb() functions, and PowerPC-radix followed that example.
But when we hooked up x86 we failed to consider this. Fix this by
(optionally) hooking tlb_remove_table() into the TLB invalidate code.
NOTE: s390 was also needing something like this and might now
be able to use the generic code again.
[ Modified to be on top of Nick's cleanups, which simplified this patch
now that tlb_flush_mmu_tlbonly() really only flushes the TLB - Linus ]
Fixes: 9e52fc2b50de ("x86/mm: Enable RCU based page table freeing (CONFIG_HAVE_RCU_TABLE_FREE=y)")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Rik van Riel <riel@surriel.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: David Miller <davem@davemloft.net>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Patch series "add support for relative references in special sections", v10.
This adds support for emitting special sections such as initcall arrays,
PCI fixups and tracepoints as relative references rather than absolute
references. This reduces the size by 50% on 64-bit architectures, but
more importantly, it removes the need for carrying relocation metadata for
these sections in relocatable kernels (e.g., for KASLR) that needs to be
fixed up at boot time. On arm64, this reduces the vmlinux footprint of
such a reference by 8x (8 byte absolute reference + 24 byte RELA entry vs
4 byte relative reference)
Patch #3 was sent out before as a single patch. This series supersedes
the previous submission. This version makes relative ksymtab entries
dependent on the new Kconfig symbol HAVE_ARCH_PREL32_RELOCATIONS rather
than trying to infer from kbuild test robot replies for which
architectures it should be blacklisted.
Patch #1 introduces the new Kconfig symbol HAVE_ARCH_PREL32_RELOCATIONS,
and sets it for the main architectures that are expected to benefit the
most from this feature, i.e., 64-bit architectures or ones that use
runtime relocations.
Patch #2 add support for #define'ing __DISABLE_EXPORTS to get rid of
ksymtab/kcrctab sections in decompressor and EFI stub objects when
rebuilding existing C files to run in a different context.
Patches #4 - #6 implement relative references for initcalls, PCI fixups
and tracepoints, respectively, all of which produce sections with order
~1000 entries on an arm64 defconfig kernel with tracing enabled. This
means we save about 28 KB of vmlinux space for each of these patches.
[From the v7 series blurb, which included the jump_label patches as well]:
For the arm64 kernel, all patches combined reduce the memory footprint
of vmlinux by about 1.3 MB (using a config copied from Ubuntu that has
KASLR enabled), of which ~1 MB is the size reduction of the RELA section
in .init, and the remaining 300 KB is reduction of .text/.data.
This patch (of 6):
Before updating certain subsystems to use place relative 32-bit
relocations in special sections, to save space and reduce the number of
absolute relocations that need to be processed at runtime by relocatable
kernels, introduce the Kconfig symbol and define it for some architectures
that should be able to support and benefit from it.
Link: http://lkml.kernel.org/r/20180704083651.24360-2-ard.biesheuvel@linaro.org
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: James Morris <jmorris@namei.org>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Cc: James Morris <james.morris@microsoft.com>
Cc: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We have a need to override the definition of
barrier_before_unreachable() for MIPS, which means we either need to add
architecture-specific code into linux/compiler-gcc.h or we need to allow
the architecture to provide a header that can define the macro before
the generic definition. The latter seems like the better approach.
A straightforward approach to the per-arch header is to make use of
asm-generic to provide a default empty header & adjust architectures
which don't need anything specific to make use of that by adding the
header to generic-y. Unfortunately this doesn't work so well due to
commit 28128c61e08e ("kconfig.h: Include compiler types to avoid missed
struct attributes") which caused linux/compiler_types.h to be included
in the compilation of every C file via the -include linux/kconfig.h flag
in c_flags.
Because the -include flag is present for all C files we compile, we need
the architecture-provided header to be present before any C files are
compiled. If any C files can be compiled prior to the asm-generic header
wrappers being generated then we hit a build failure due to missing
header. Such cases do exist - one pointed out by the kbuild test robot
is the compilation of arch/ia64/kernel/nr-irqs.c, which occurs as part
of the archprepare target [1].
This leaves us with a few options:
1) Use generic-y & fix any build failures we find by enforcing
ordering such that the asm-generic target occurs before any C
compilation, such that linux/compiler_types.h can always include
the generated asm-generic wrapper which in turn includes the empty
asm-generic header. This would rely on us finding all the
problematic cases - I don't know for sure that the ia64 issue is
the only one.
2) Add an actual empty header to each architecture, so that we don't
need the generated asm-generic wrapper. This seems messy.
3) Give up & add #ifdef CONFIG_MIPS or similar to
linux/compiler_types.h. This seems messy too.
4) Include the arch header only when it's actually needed, removing
the need for the asm-generic wrapper for all other architectures.
This patch allows us to use approach 4, by including an asm/compiler.h
header from linux/compiler_types.h after the inclusion of the
compiler-specific linux/compiler-*.h header(s). We do this
conditionally, only when CONFIG_HAVE_ARCH_COMPILER_H is selected, in
order to avoid the need for asm-generic wrappers & the associated build
ordering issue described above. The asm/compiler.h header is included
after the generic linux/compiler-*.h header(s) for consistency with the
way linux/compiler-intel.h & linux/compiler-clang.h are included after
the linux/compiler-gcc.h header that they override.
[1] https://lists.01.org/pipermail/kbuild-all/2018-August/051175.html
Signed-off-by: Paul Burton <paul.burton@mips.com>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Patchwork: https://patchwork.linux-mips.org/patch/20269/
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: James Hogan <jhogan@kernel.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-arch@vger.kernel.org
Cc: linux-kbuild@vger.kernel.org
Cc: linux-mips@linux-mips.org
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git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kconfig consolidation from Masahiro Yamada:
"Consolidation of Kconfig files by Christoph Hellwig.
Move the source statements of arch-independent Kconfig files instead
of duplicating the includes in every arch/$(SRCARCH)/Kconfig"
* tag 'kconfig-v4.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kconfig: add a Memory Management options" menu
kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt
kconfig: use a menu in arch/Kconfig to reduce clutter
kconfig: include kernel/Kconfig.preempt from init/Kconfig
Kconfig: consolidate the "Kernel hacking" menu
kconfig: include common Kconfig files from top-level Kconfig
kconfig: remove duplicate SWAP symbol defintions
um: create a proper drivers Kconfig
um: cleanup Kconfig files
um: stop abusing KBUILD_KCONFIG
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git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull gcc plugin cleanups from Kees Cook:
- Kconfig and Makefile clean-ups (Masahiro Yamada, Kees Cook)
- gcc-common.h definition clean-ups (Alexander Popov)
* tag 'gcc-plugin-cleanup-v4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
gcc-plugins: Clean up the cgraph_create_edge* macros
gcc-plugins: Regularize Makefile.gcc-plugins
gcc-plugins: split out Kconfig entries to scripts/gcc-plugins/Kconfig
gcc-plugins: remove unused GCC_PLUGIN_SUBDIR
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Put everything in arch/Kconfig into a General options menu
so that they don't clutter up the main/major/primary list of
menu options.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Almost all architectures include it. Add a ARCH_NO_PREEMPT symbol to
disable preempt support for alpha, hexagon, non-coldfire m68k and
user mode Linux.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Instead of duplicating the source statements in every architecture just
do it once in the toplevel Kconfig file.
Note that with this the inclusion of arch/$(SRCARCH/Kconfig moves out of
the top-level Kconfig into arch/Kconfig so that don't violate ordering
constraits while keeping a sensible menu structure.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Collect relevant code into the scripts/gcc-plugins directory.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
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Provide a command line and a sysfs knob to control SMT.
The command line options are:
'nosmt': Enumerate secondary threads, but do not online them
'nosmt=force': Ignore secondary threads completely during enumeration
via MP table and ACPI/MADT.
The sysfs control file has the following states (read/write):
'on': SMT is enabled. Secondary threads can be freely onlined
'off': SMT is disabled. Secondary threads, even if enumerated
cannot be onlined
'forceoff': SMT is permanentely disabled. Writes to the control
file are rejected.
'notsupported': SMT is not supported by the CPU
The command line option 'nosmt' sets the sysfs control to 'off'. This
can be changed to 'on' to reenable SMT during runtime.
The command line option 'nosmt=force' sets the sysfs control to
'forceoff'. This cannot be changed during runtime.
When SMT is 'on' and the control file is changed to 'off' then all online
secondary threads are offlined and attempts to online a secondary thread
later on are rejected.
When SMT is 'off' and the control file is changed to 'on' then secondary
threads can be onlined again. The 'off' -> 'on' transition does not
automatically online the secondary threads.
When the control file is set to 'forceoff', the behaviour is the same as
setting it to 'off', but the operation is irreversible and later writes to
the control file are rejected.
When the control status is 'notsupported' then writes to the control file
are rejected.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
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As we move stuff around, some doc references are broken. Fix some of
them via this script:
./scripts/documentation-file-ref-check --fix
Manually checked if the produced result is valid, removing a few
false-positives.
Acked-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
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HAVE_CC_STACKPROTECTOR should be selected by architectures with stack
canary implementation. It is not about the compiler support.
For the consistency with commit 050e9baa9dc9 ("Kbuild: rename
CC_STACKPROTECTOR[_STRONG] config variables"), remove 'CC_' from the
config symbol.
I moved the 'select' lines to keep the alphabetical sorting.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The changes to automatically test for working stack protector compiler
support in the Kconfig files removed the special STACKPROTECTOR_AUTO
option that picked the strongest stack protector that the compiler
supported.
That was all a nice cleanup - it makes no sense to have the AUTO case
now that the Kconfig phase can just determine the compiler support
directly.
HOWEVER.
It also meant that doing "make oldconfig" would now _disable_ the strong
stackprotector if you had AUTO enabled, because in a legacy config file,
the sane stack protector configuration would look like
CONFIG_HAVE_CC_STACKPROTECTOR=y
# CONFIG_CC_STACKPROTECTOR_NONE is not set
# CONFIG_CC_STACKPROTECTOR_REGULAR is not set
# CONFIG_CC_STACKPROTECTOR_STRONG is not set
CONFIG_CC_STACKPROTECTOR_AUTO=y
and when you ran this through "make oldconfig" with the Kbuild changes,
it would ask you about the regular CONFIG_CC_STACKPROTECTOR (that had
been renamed from CONFIG_CC_STACKPROTECTOR_REGULAR to just
CONFIG_CC_STACKPROTECTOR), but it would think that the STRONG version
used to be disabled (because it was really enabled by AUTO), and would
disable it in the new config, resulting in:
CONFIG_HAVE_CC_STACKPROTECTOR=y
CONFIG_CC_HAS_STACKPROTECTOR_NONE=y
CONFIG_CC_STACKPROTECTOR=y
# CONFIG_CC_STACKPROTECTOR_STRONG is not set
CONFIG_CC_HAS_SANE_STACKPROTECTOR=y
That's dangerously subtle - people could suddenly find themselves with
the weaker stack protector setup without even realizing.
The solution here is to just rename not just the old RECULAR stack
protector option, but also the strong one. This does that by just
removing the CC_ prefix entirely for the user choices, because it really
is not about the compiler support (the compiler support now instead
automatially impacts _visibility_ of the options to users).
This results in "make oldconfig" actually asking the user for their
choice, so that we don't have any silent subtle security model changes.
The end result would generally look like this:
CONFIG_HAVE_CC_STACKPROTECTOR=y
CONFIG_CC_HAS_STACKPROTECTOR_NONE=y
CONFIG_STACKPROTECTOR=y
CONFIG_STACKPROTECTOR_STRONG=y
CONFIG_CC_HAS_SANE_STACKPROTECTOR=y
where the "CC_" versions really are about internal compiler
infrastructure, not the user selections.
Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull more Kbuild updates from Masahiro Yamada:
- fix some bugs introduced by the recent Kconfig syntax extension
- add some symbols about compiler information in Kconfig, such as
CC_IS_GCC, CC_IS_CLANG, GCC_VERSION, etc.
- test compiler capability for the stack protector in Kconfig, and
clean-up Makefile
- test compiler capability for GCC-plugins in Kconfig, and clean-up
Makefile
- allow to enable GCC-plugins for COMPILE_TEST
- test compiler capability for KCOV in Kconfig and correct dependency
- remove auto-detect mode of the GCOV format, which is now more nicely
handled in Kconfig
- test compiler capability for mprofile-kernel on PowerPC, and clean-up
Makefile
- misc cleanups
* tag 'kbuild-v4.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
linux/linkage.h: replace VMLINUX_SYMBOL_STR() with __stringify()
kconfig: fix localmodconfig
sh: remove no-op macro VMLINUX_SYMBOL()
powerpc/kbuild: move -mprofile-kernel check to Kconfig
Documentation: kconfig: add recommended way to describe compiler support
gcc-plugins: disable GCC_PLUGIN_STRUCTLEAK_BYREF_ALL for COMPILE_TEST
gcc-plugins: allow to enable GCC_PLUGINS for COMPILE_TEST
gcc-plugins: test plugin support in Kconfig and clean up Makefile
gcc-plugins: move GCC version check for PowerPC to Kconfig
kcov: test compiler capability in Kconfig and correct dependency
gcov: remove CONFIG_GCOV_FORMAT_AUTODETECT
arm64: move GCC version check for ARCH_SUPPORTS_INT128 to Kconfig
kconfig: add CC_IS_CLANG and CLANG_VERSION
kconfig: add CC_IS_GCC and GCC_VERSION
stack-protector: test compiler capability in Kconfig and drop AUTO mode
kbuild: fix endless syncconfig in case arch Makefile sets CROSS_COMPILE
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We have enabled GCC_PLUGINS for COMPILE_TEST, but allmodconfig now
produces new warnings.
CC [M] drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_n.o
drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_n.c: In function ‘wlc_phy_workarounds_nphy_rev7’:
drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_n.c:16563:1: warning: the frame size of 3128 bytes is larger than 2048 bytes [-Wframe-larger-than=]
}
^
drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_n.c: In function ‘wlc_phy_workarounds_nphy_rev3’:
drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_n.c:16905:1: warning: the frame size of 2800 bytes is larger than 2048 bytes [-Wframe-larger-than=]
}
^
drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_n.c: In function ‘wlc_phy_cal_txiqlo_nphy’:
drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_n.c:26033:1: warning: the frame size of 2488 bytes is larger than 2048 bytes [-Wframe-larger-than=]
}
^
It looks like GCC_PLUGIN_STRUCTLEAK_BYREF_ALL is causing this.
Add "depends on !COMPILE_TEST" to not dirturb the compile test.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
|
|
Now that the compiler's plugin support is checked in Kconfig,
all{yes,mod}config will not be bothered.
Remove 'depends on !COMPILE_TEST' for GCC_PLUGINS.
'depends on !COMPILE_TEST' for the following three are still kept:
GCC_PLUGIN_CYC_COMPLEXITY
GCC_PLUGIN_STRUCTLEAK_VERBOSE
GCC_PLUGIN_RANDSTRUCT_PERFORMANCE
Kees suggested to do so because the first two are too noisy, and the
last one would reduce the compile test coverage. I commented the
reasons in arch/Kconfig.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Kees Cook <keescook@chromium.org>
|
|
Run scripts/gcc-plugin.sh from Kconfig so that users can enable
GCC_PLUGINS only when the compiler supports building plugins.
Kconfig defines a new symbol, PLUGIN_HOSTCC. This will contain
the compiler (g++ or gcc) used for building plugins, or empty
if the plugin can not be supported at all.
This allows us to remove all ugly testing in Makefile.gcc-plugins.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Kees Cook <keescook@chromium.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull restartable sequence support from Thomas Gleixner:
"The restartable sequences syscall (finally):
After a lot of back and forth discussion and massive delays caused by
the speculative distraction of maintainers, the core set of
restartable sequences has finally reached a consensus.
It comes with the basic non disputed core implementation along with
support for arm, powerpc and x86 and a full set of selftests
It was exposed to linux-next earlier this week, so it does not fully
comply with the merge window requirements, but there is really no
point to drag it out for yet another cycle"
* 'core-rseq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
rseq/selftests: Provide Makefile, scripts, gitignore
rseq/selftests: Provide parametrized tests
rseq/selftests: Provide basic percpu ops test
rseq/selftests: Provide basic test
rseq/selftests: Provide rseq library
selftests/lib.mk: Introduce OVERRIDE_TARGETS
powerpc: Wire up restartable sequences system call
powerpc: Add syscall detection for restartable sequences
powerpc: Add support for restartable sequences
x86: Wire up restartable sequence system call
x86: Add support for restartable sequences
arm: Wire up restartable sequences system call
arm: Add syscall detection for restartable sequences
arm: Add restartable sequences support
rseq: Introduce restartable sequences system call
uapi/headers: Provide types_32_64.h
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|
Move the test for -fstack-protector(-strong) option to Kconfig.
If the compiler does not support the option, the corresponding menu
is automatically hidden. If STRONG is not supported, it will fall
back to REGULAR. If REGULAR is not supported, it will be disabled.
This means, AUTO is implicitly handled by the dependency solver of
Kconfig, hence removed.
I also turned the 'choice' into only two boolean symbols. The use of
'choice' is not a good idea here, because all of all{yes,mod,no}config
would choose the first visible value, while we want allnoconfig to
disable as many features as possible.
X86 has additional shell scripts in case the compiler supports those
options, but generates broken code. I added CC_HAS_SANE_STACKPROTECTOR
to test this. I had to add -m32 to gcc-x86_32-has-stack-protector.sh
to make it work correctly.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Kees Cook <keescook@chromium.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- improve fixdep to coalesce consecutive slashes in dep-files
- fix some issues of the maintainer string generation in deb-pkg script
- remove unused CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX and clean-up
several tools and linker scripts
- clean-up modpost
- allow to enable the dead code/data elimination for PowerPC in EXPERT
mode
- improve two coccinelle scripts for better performance
- pass endianness and machine size flags to sparse for all architecture
- misc fixes
* tag 'kbuild-v4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (25 commits)
kbuild: add machine size to CHECKFLAGS
kbuild: add endianness flag to CHEKCFLAGS
kbuild: $(CHECK) doesnt need NOSTDINC_FLAGS twice
scripts: Fixed printf format mismatch
scripts/tags.sh: use `find` for $ALLSOURCE_ARCHS generation
coccinelle: deref_null: improve performance
coccinelle: mini_lock: improve performance
powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected
kbuild: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selectable if enabled
kbuild: LD_DEAD_CODE_DATA_ELIMINATION no -ffunction-sections/-fdata-sections for module build
kbuild: Fix asm-generic/vmlinux.lds.h for LD_DEAD_CODE_DATA_ELIMINATION
modpost: constify *modname function argument where possible
modpost: remove redundant is_vmlinux() test
modpost: use strstarts() helper more widely
modpost: pass struct elf_info pointer to get_modinfo()
checkpatch: remove VMLINUX_SYMBOL() check
vmlinux.lds.h: remove no-op macro VMLINUX_SYMBOL()
kbuild: remove CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
export.h: remove code for prefixing symbols with underscore
depmod.sh: remove symbol prefix support
...
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Expose a new system call allowing each thread to register one userspace
memory area to be used as an ABI between kernel and user-space for two
purposes: user-space restartable sequences and quick access to read the
current CPU number value from user-space.
* Restartable sequences (per-cpu atomics)
Restartables sequences allow user-space to perform update operations on
per-cpu data without requiring heavy-weight atomic operations.
The restartable critical sections (percpu atomics) work has been started
by Paul Turner and Andrew Hunter. It lets the kernel handle restart of
critical sections. [1] [2] The re-implementation proposed here brings a
few simplifications to the ABI which facilitates porting to other
architectures and speeds up the user-space fast path.
Here are benchmarks of various rseq use-cases.
Test hardware:
arm32: ARMv7 Processor rev 4 (v7l) "Cubietruck", 2-core
x86-64: Intel E5-2630 v3@2.40GHz, 16-core, hyperthreading
The following benchmarks were all performed on a single thread.
* Per-CPU statistic counter increment
getcpu+atomic (ns/op) rseq (ns/op) speedup
arm32: 344.0 31.4 11.0
x86-64: 15.3 2.0 7.7
* LTTng-UST: write event 32-bit header, 32-bit payload into tracer
per-cpu buffer
getcpu+atomic (ns/op) rseq (ns/op) speedup
arm32: 2502.0 2250.0 1.1
x86-64: 117.4 98.0 1.2
* liburcu percpu: lock-unlock pair, dereference, read/compare word
getcpu+atomic (ns/op) rseq (ns/op) speedup
arm32: 751.0 128.5 5.8
x86-64: 53.4 28.6 1.9
* jemalloc memory allocator adapted to use rseq
Using rseq with per-cpu memory pools in jemalloc at Facebook (based on
rseq 2016 implementation):
The production workload response-time has 1-2% gain avg. latency, and
the P99 overall latency drops by 2-3%.
* Reading the current CPU number
Speeding up reading the current CPU number on which the caller thread is
running is done by keeping the current CPU number up do date within the
cpu_id field of the memory area registered by the thread. This is done
by making scheduler preemption set the TIF_NOTIFY_RESUME flag on the
current thread. Upon return to user-space, a notify-resume handler
updates the current CPU value within the registered user-space memory
area. User-space can then read the current CPU number directly from
memory.
Keeping the current cpu id in a memory area shared between kernel and
user-space is an improvement over current mechanisms available to read
the current CPU number, which has the following benefits over
alternative approaches:
- 35x speedup on ARM vs system call through glibc
- 20x speedup on x86 compared to calling glibc, which calls vdso
executing a "lsl" instruction,
- 14x speedup on x86 compared to inlined "lsl" instruction,
- Unlike vdso approaches, this cpu_id value can be read from an inline
assembly, which makes it a useful building block for restartable
sequences.
- The approach of reading the cpu id through memory mapping shared
between kernel and user-space is portable (e.g. ARM), which is not the
case for the lsl-based x86 vdso.
On x86, yet another possible approach would be to use the gs segment
selector to point to user-space per-cpu data. This approach performs
similarly to the cpu id cache, but it has two disadvantages: it is
not portable, and it is incompatible with existing applications already
using the gs segment selector for other purposes.
Benchmarking various approaches for reading the current CPU number:
ARMv7 Processor rev 4 (v7l)
Machine model: Cubietruck
- Baseline (empty loop): 8.4 ns
- Read CPU from rseq cpu_id: 16.7 ns
- Read CPU from rseq cpu_id (lazy register): 19.8 ns
- glibc 2.19-0ubuntu6.6 getcpu: 301.8 ns
- getcpu system call: 234.9 ns
x86-64 Intel(R) Xeon(R) CPU E5-2630 v3 @ 2.40GHz:
- Baseline (empty loop): 0.8 ns
- Read CPU from rseq cpu_id: 0.8 ns
- Read CPU from rseq cpu_id (lazy register): 0.8 ns
- Read using gs segment selector: 0.8 ns
- "lsl" inline assembly: 13.0 ns
- glibc 2.19-0ubuntu6 getcpu: 16.6 ns
- getcpu system call: 53.9 ns
- Speed (benchmark taken on v8 of patchset)
Running 10 runs of hackbench -l 100000 seems to indicate, contrary to
expectations, that enabling CONFIG_RSEQ slightly accelerates the
scheduler:
Configuration: 2 sockets * 8-core Intel(R) Xeon(R) CPU E5-2630 v3 @
2.40GHz (directly on hardware, hyperthreading disabled in BIOS, energy
saving disabled in BIOS, turboboost disabled in BIOS, cpuidle.off=1
kernel parameter), with a Linux v4.6 defconfig+localyesconfig,
restartable sequences series applied.
* CONFIG_RSEQ=n
avg.: 41.37 s
std.dev.: 0.36 s
* CONFIG_RSEQ=y
avg.: 40.46 s
std.dev.: 0.33 s
- Size
On x86-64, between CONFIG_RSEQ=n/y, the text size increase of vmlinux is
567 bytes, and the data size increase of vmlinux is 5696 bytes.
[1] https://lwn.net/Articles/650333/
[2] http://www.linuxplumbersconf.org/2013/ocw/system/presentations/1695/original/LPC%20-%20PerCpu%20Atomics.pdf
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Watson <davejwatson@fb.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Chris Lameter <cl@linux.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Andrew Hunter <ahh@google.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Maurer <bmaurer@fb.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-api@vger.kernel.org
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20151027235635.16059.11630.stgit@pjt-glaptop.roam.corp.google.com
Link: http://lkml.kernel.org/r/20150624222609.6116.86035.stgit@kitami.mtv.corp.google.com
Link: https://lkml.kernel.org/r/20180602124408.8430-3-mathieu.desnoyers@efficios.com
|
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timers and timekeeping updates from Thomas Gleixner:
- Core infrastucture work for Y2038 to address the COMPAT interfaces:
+ Add a new Y2038 safe __kernel_timespec and use it in the core
code
+ Introduce config switches which allow to control the various
compat mechanisms
+ Use the new config switch in the posix timer code to control the
32bit compat syscall implementation.
- Prevent bogus selection of CPU local clocksources which causes an
endless reselection loop
- Remove the extra kthread in the clocksource code which has no value
and just adds another level of indirection
- The usual bunch of trivial updates, cleanups and fixlets all over the
place
- More SPDX conversions
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
clocksource/drivers/mxs_timer: Switch to SPDX identifier
clocksource/drivers/timer-imx-tpm: Switch to SPDX identifier
clocksource/drivers/timer-imx-gpt: Switch to SPDX identifier
clocksource/drivers/timer-imx-gpt: Remove outdated file path
clocksource/drivers/arc_timer: Add comments about locking while read GFRC
clocksource/drivers/mips-gic-timer: Add pr_fmt and reword pr_* messages
clocksource/drivers/sprd: Fix Kconfig dependency
clocksource: Move inline keyword to the beginning of function declarations
timer_list: Remove unused function pointer typedef
timers: Adjust a kernel-doc comment
tick: Prefer a lower rating device only if it's CPU local device
clocksource: Remove kthread
time: Change nanosleep to safe __kernel_* types
time: Change types to new y2038 safe __kernel_* types
time: Fix get_timespec64() for y2038 safe compat interfaces
time: Add new y2038 safe __kernel_timespec
posix-timers: Make compat syscalls depend on CONFIG_COMPAT_32BIT_TIME
time: Introduce CONFIG_COMPAT_32BIT_TIME
time: Introduce CONFIG_64BIT_TIME in architectures
compat: Enable compat_get/put_timespec64 always
...
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Pull dma-mapping updates from Christoph Hellwig:
- replace the force_dma flag with a dma_configure bus method. (Nipun
Gupta, although one patch is іncorrectly attributed to me due to a
git rebase bug)
- use GFP_DMA32 more agressively in dma-direct. (Takashi Iwai)
- remove PCI_DMA_BUS_IS_PHYS and rely on the dma-mapping API to do the
right thing for bounce buffering.
- move dma-debug initialization to common code, and apply a few
cleanups to the dma-debug code.
- cleanup the Kconfig mess around swiotlb selection
- swiotlb comment fixup (Yisheng Xie)
- a trivial swiotlb fix. (Dan Carpenter)
- support swiotlb on RISC-V. (based on a patch from Palmer Dabbelt)
- add a new generic dma-noncoherent dma_map_ops implementation and use
it for arc, c6x and nds32.
- improve scatterlist validity checking in dma-debug. (Robin Murphy)
- add a struct device quirk to limit the dma-mask to 32-bit due to
bridge/system issues, and switch x86 to use it instead of a local
hack for VIA bridges.
- handle devices without a dma_mask more gracefully in the dma-direct
code.
* tag 'dma-mapping-4.18' of git://git.infradead.org/users/hch/dma-mapping: (48 commits)
dma-direct: don't crash on device without dma_mask
nds32: use generic dma_noncoherent_ops
nds32: implement the unmap_sg DMA operation
nds32: consolidate DMA cache maintainance routines
x86/pci-dma: switch the VIA 32-bit DMA quirk to use the struct device flag
x86/pci-dma: remove the explicit nodac and allowdac option
x86/pci-dma: remove the experimental forcesac boot option
Documentation/x86: remove a stray reference to pci-nommu.c
core, dma-direct: add a flag 32-bit dma limits
dma-mapping: remove unused gfp_t parameter to arch_dma_alloc_attrs
dma-debug: check scatterlist segments
c6x: use generic dma_noncoherent_ops
arc: use generic dma_noncoherent_ops
arc: fix arc_dma_{map,unmap}_page
arc: fix arc_dma_sync_sg_for_{cpu,device}
arc: simplify arc_dma_sync_single_for_{cpu,device}
dma-mapping: provide a generic dma-noncoherent implementation
dma-mapping: simplify Kconfig dependencies
riscv: add swiotlb support
riscv: only enable ZONE_DMA32 for 64-bit
...
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Architectures that are capable can select
HAVE_LD_DEAD_CODE_DATA_ELIMINATION to enable selection of that
option (as an EXPERT kernel option).
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX was selected by BLACKFIN, METAG.
They were removed by commit 4ba66a976072 ("arch: remove blackfin port"),
commit bb6fb6dfcc17 ("metag: Remove arch/metag/"), respectively.
No more architecture enables CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX.
Clean up the rest of scripts, and remove the Kconfig entry.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
|
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Currently STRUCTLEAK inserts initialization out of live scope of variables
from KASAN point of view. This leads to KASAN false positive reports.
Prohibit this combination for now.
Link: http://lkml.kernel.org/r/20180419172451.104700-1-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dennis Zhou <dennisszhou@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
There is no arch specific code required for dma-debug, so there is no
need to opt into the support either.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
|
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Compat functions are now used to support 32 bit time_t in
compat mode on 64 bit architectures and in native mode on
32 bit architectures.
Introduce COMPAT_32BIT_TIME to conditionally compile these
functions.
Note that turning off 32 bit time_t support requires more
changes on architecture side. For instance, architecure
syscall tables need to be updated to drop support for 32 bit
time_t syscalls.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
|
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There are a total of 53 system calls (aside |