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<title>linux-dev/arch/arm/kernel/Makefile, branch master</title>
<subtitle>Linux kernel development work - see feature branches</subtitle>
<id>https://git.zx2c4.com/linux-dev/atom/arch/arm/kernel/Makefile?h=master</id>
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<updated>2022-10-10T19:00:45Z</updated>
<entry>
<title>Merge tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild</title>
<updated>2022-10-10T19:00:45Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-10-10T19:00:45Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=8afc66e8d43be8edcf442165b70d50dd33091e68'/>
<id>urn:sha1:8afc66e8d43be8edcf442165b70d50dd33091e68</id>
<content type='text'>
Pull Kbuild updates from Masahiro Yamada:

 - Remove potentially incomplete targets when Kbuid is interrupted by
   SIGINT etc in case GNU Make may miss to do that when stderr is piped
   to another program.

 - Rewrite the single target build so it works more correctly.

 - Fix rpm-pkg builds with V=1.

 - List top-level subdirectories in ./Kbuild.

 - Ignore auto-generated __kstrtab_* and __kstrtabns_* symbols in
   kallsyms.

 - Avoid two different modules in lib/zstd/ having shared code, which
   potentially causes building the common code as build-in and modular
   back-and-forth.

 - Unify two modpost invocations to optimize the build process.

 - Remove head-y syntax in favor of linker scripts for placing
   particular sections in the head of vmlinux.

 - Bump the minimal GNU Make version to 3.82.

 - Clean up misc Makefiles and scripts.

* tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (41 commits)
  docs: bump minimal GNU Make version to 3.82
  ia64: simplify esi object addition in Makefile
  Revert "kbuild: Check if linker supports the -X option"
  kbuild: rebuild .vmlinux.export.o when its prerequisite is updated
  kbuild: move modules.builtin(.modinfo) rules to Makefile.vmlinux_o
  zstd: Fixing mixed module-builtin objects
  kallsyms: ignore __kstrtab_* and __kstrtabns_* symbols
  kallsyms: take the input file instead of reading stdin
  kallsyms: drop duplicated ignore patterns from kallsyms.c
  kbuild: reuse mksysmap output for kallsyms
  mksysmap: update comment about __crc_*
  kbuild: remove head-y syntax
  kbuild: use obj-y instead extra-y for objects placed at the head
  kbuild: hide error checker logs for V=1 builds
  kbuild: re-run modpost when it is updated
  kbuild: unify two modpost invocations
  kbuild: move vmlinux.o rule to the top Makefile
  kbuild: move .vmlinux.objs rule to Makefile.modpost
  kbuild: list sub-directories in ./Kbuild
  Makefile.compiler: replace cc-ifversion with compiler-specific macros
  ...
</content>
</entry>
<entry>
<title>kbuild: use obj-y instead extra-y for objects placed at the head</title>
<updated>2022-10-02T09:04:05Z</updated>
<author>
<name>Masahiro Yamada</name>
<email>masahiroy@kernel.org</email>
</author>
<published>2022-09-24T18:19:14Z</published>
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<id>urn:sha1:3216484550610470013b7ce1c9ed272da0a74589</id>
<content type='text'>
The objects placed at the head of vmlinux need special treatments:

 - arch/$(SRCARCH)/Makefile adds them to head-y in order to place
   them before other archives in the linker command line.

 - arch/$(SRCARCH)/kernel/Makefile adds them to extra-y instead of
   obj-y to avoid them going into built-in.a.

This commit gets rid of the latter.

Create vmlinux.a to collect all the objects that are unconditionally
linked to vmlinux. The objects listed in head-y are moved to the head
of vmlinux.a by using 'ar m'.

With this, arch/$(SRCARCH)/kernel/Makefile can consistently use obj-y
for builtin objects.

There is no *.o that is directly linked to vmlinux. Drop unneeded code
in scripts/clang-tools/gen_compile_commands.py.

$(AR) mPi needs 'T' to workaround the llvm-ar bug. The fix was suggested
by Nathan Chancellor [1].

[1]: https://lore.kernel.org/llvm/YyjjT5gQ2hGMH0ni@dev-arch.thelio-3990X/

Signed-off-by: Masahiro Yamada &lt;masahiroy@kernel.org&gt;
Tested-by: Nick Desaulniers &lt;ndesaulniers@google.com&gt;
Reviewed-by: Nicolas Schier &lt;nicolas@fjasle.eu&gt;
</content>
</entry>
<entry>
<title>ARM: footbridge: move isa-dma support into footbridge</title>
<updated>2022-09-09T15:14:34Z</updated>
<author>
<name>Arnd Bergmann</name>
<email>arnd@arndb.de</email>
</author>
<published>2022-07-01T09:44:52Z</published>
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<id>urn:sha1:e7536617baec3b4717a37795cec306df9d655d07</id>
<content type='text'>
The dma-isa.c was shared between footbridge and shark a long time ago,
but as shark was removed, it can be made footbridge specific again.

The fb_dma bits in turn are not used at all and can be removed.

All the ISA related files are now built into the platform regardless
of CONFIG_ISA, as they just refer to on-chip devices rather than actual
ISA cards.

Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Tested-by: Marc Zyngier &lt;maz@kernel.org&gt;
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
</content>
</entry>
<entry>
<title>Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm</title>
<updated>2022-03-24T00:35:57Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-03-24T00:35:57Z</published>
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<id>urn:sha1:9c0e6a89b592f4c4e4d769dbc22d399ab0685159</id>
<content type='text'>
Pull ARM updates from Russell King:
 "Updates for IRQ stacks and virtually mapped stack support, and ftrace:

   - Support for IRQ and vmap'ed stacks

     This covers all the work related to implementing IRQ stacks and
     vmap'ed stacks for all 32-bit ARM systems that are currently
     supported by the Linux kernel, including RiscPC and Footbridge. It
     has been submitted for review in four different waves:

      - IRQ stacks support for v7 SMP systems [0]

      - vmap'ed stacks support for v7 SMP systems[1]

      - extending support for both IRQ stacks and vmap'ed stacks for all
        remaining configurations, including v6/v7 SMP multiplatform
        kernels and uniprocessor configurations including v7-M [2]

      - fixes and updates in [3]

   - ftrace fixes and cleanups

     Make all flavors of ftrace available on all builds, regardless of
     ISA choice, unwinder choice or compiler [4]:

      - use ADD not POP where possible

      - fix a couple of Thumb2 related issues

      - enable HAVE_FUNCTION_GRAPH_FP_TEST for robustness

      - enable the graph tracer with the EABI unwinder

      - avoid clobbering frame pointer registers to make Clang happy

   - Fixes for the above"

[0] https://lore.kernel.org/linux-arm-kernel/20211115084732.3704393-1-ardb@kernel.org/
[1] https://lore.kernel.org/linux-arm-kernel/20211122092816.2865873-1-ardb@kernel.org/
[2] https://lore.kernel.org/linux-arm-kernel/20211206164659.1495084-1-ardb@kernel.org/
[3] https://lore.kernel.org/linux-arm-kernel/20220124174744.1054712-1-ardb@kernel.org/
[4] https://lore.kernel.org/linux-arm-kernel/20220203082204.1176734-1-ardb@kernel.org/

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (62 commits)
  ARM: fix building NOMMU ARMv4/v5 kernels
  ARM: unwind: only permit stack switch when unwinding call_with_stack()
  ARM: Revert "unwind: dump exception stack from calling frame"
  ARM: entry: fix unwinder problems caused by IRQ stacks
  ARM: unwind: set frame.pc correctly for current-thread unwinding
  ARM: 9184/1: return_address: disable again for CONFIG_ARM_UNWIND=y
  ARM: 9183/1: unwind: avoid spurious warnings on bogus code addresses
  Revert "ARM: 9144/1: forbid ftrace with clang and thumb2_kernel"
  ARM: mach-bcm: disable ftrace in SMC invocation routines
  ARM: cacheflush: avoid clobbering the frame pointer
  ARM: kprobes: treat R7 as the frame pointer register in Thumb2 builds
  ARM: ftrace: enable the graph tracer with the EABI unwinder
  ARM: unwind: track location of LR value in stack frame
  ARM: ftrace: enable HAVE_FUNCTION_GRAPH_FP_TEST
  ARM: ftrace: avoid unnecessary literal loads
  ARM: ftrace: avoid redundant loads or clobbering IP
  ARM: ftrace: use trampolines to keep .init.text in branching range
  ARM: ftrace: use ADD not POP to counter PUSH at entry
  ARM: ftrace: ensure that ADR takes the Thumb bit into account
  ARM: make get_current() and __my_cpu_offset() __always_inline
  ...
</content>
</entry>
<entry>
<title>ARM: 9184/1: return_address: disable again for CONFIG_ARM_UNWIND=y</title>
<updated>2022-03-07T11:43:12Z</updated>
<author>
<name>Ard Biesheuvel</name>
<email>ardb@kernel.org</email>
</author>
<published>2022-03-02T11:38:18Z</published>
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<id>urn:sha1:6845d64d51cf69c096176e34864e161429bcb664</id>
<content type='text'>
Commit 41918ec82eb6 ("ARM: ftrace: enable the graph tracer with the EABI
unwinder") removed the dummy version of return_address() that was
provided for the CONFIG_ARM_UNWIND=y case, on the assumption that the
removal of the kernel_text_address() call from unwind_frame() in the
preceding patch made it safe to do so.

However, this turns out not to be the case: Corentin reports warnings
about suspicious RCU usage and other strange behavior that seems to
originate in the stack unwinding that occurs in return_address().

Given that the function graph tracer (which is what these changes were
enabling for CONFIG_ARM_UNWIND=y builds) does not appear to care about
this distinction, let's revert return_address() to the old state.

Cc: Corentin Labbe &lt;clabbe.montjoie@gmail.com&gt;
Fixes: 41918ec82eb6 ("ARM: ftrace: enable the graph tracer with the EABI unwinder")
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Reported-by: Corentin Labbe &lt;clabbe.montjoie@gmail.com&gt;
Tested-by: Corentin Labbe &lt;clabbe.montjoie@gmail.com&gt;
Signed-off-by: Russell King (Oracle) &lt;rmk+kernel@armlinux.org.uk&gt;
</content>
</entry>
<entry>
<title>ARM: report Spectre v2 status through sysfs</title>
<updated>2022-03-05T10:41:22Z</updated>
<author>
<name>Russell King (Oracle)</name>
<email>rmk+kernel@armlinux.org.uk</email>
</author>
<published>2022-02-11T16:45:54Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=9dd78194a3722fa6712192cdd4f7032d45112a9a'/>
<id>urn:sha1:9dd78194a3722fa6712192cdd4f7032d45112a9a</id>
<content type='text'>
As per other architectures, add support for reporting the Spectre
vulnerability status via sysfs CPU.

Acked-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Signed-off-by: Russell King (Oracle) &lt;rmk+kernel@armlinux.org.uk&gt;
</content>
</entry>
<entry>
<title>ARM: ftrace: enable the graph tracer with the EABI unwinder</title>
<updated>2022-02-09T08:13:59Z</updated>
<author>
<name>Ard Biesheuvel</name>
<email>ardb@kernel.org</email>
</author>
<published>2022-01-25T14:55:24Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=41918ec82eb6f80c8b401422f27ca76c85aa0cb7'/>
<id>urn:sha1:41918ec82eb6f80c8b401422f27ca76c85aa0cb7</id>
<content type='text'>
Enable the function graph tracer in combination with the EABI unwinder,
so that Thumb2 builds or Clang ARM builds can make use of it.

This involves using the unwinder to locate the return address of an
instrumented function on the stack, so that it can be overridden and
made to refer to the ftrace handling routines that need to be called at
function return.

Given that for these builds, it is not guaranteed that the value of the
link register is stored on the stack, fall back to the stack slot that
will be used by the ftrace exit code to restore LR in the instrumented
function's execution context.

Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Reviewed-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
</content>
</entry>
<entry>
<title>ARM: unwind: track location of LR value in stack frame</title>
<updated>2022-02-09T08:13:43Z</updated>
<author>
<name>Ard Biesheuvel</name>
<email>ardb@kernel.org</email>
</author>
<published>2022-01-24T15:49:09Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=538b9265c063f081ca6b1228d242575a1db60711'/>
<id>urn:sha1:538b9265c063f081ca6b1228d242575a1db60711</id>
<content type='text'>
The ftrace graph tracer needs to override the return address of an
instrumented function, in order to install a hook that gets invoked when
the function returns again.

Currently, we only support this when building for ARM using GCC with
frame pointers, as in this case, it is guaranteed that the function will
reload LR from [FP, #-4] in all cases, and we can simply pass that
address to the ftrace code.

In order to support this for configurations that rely on the EABI
unwinder, such as Thumb2 builds, make the unwinder keep track of the
address from which LR was unwound, permitting ftrace to make use of this
in a subsequent patch.

Drop the call to is_kernel_text_address(), which is problematic in terms
of ftrace recursion, given that it may be instrumented itself. The call
is redundant anyway, as no unwind directives will be found unless the PC
points to memory that is known to contain executable code.

Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Reviewed-by: Nick Desaulniers &lt;ndesaulniers@google.com&gt;
</content>
</entry>
<entry>
<title>Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux</title>
<updated>2020-12-22T21:34:27Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2020-12-22T21:34:27Z</published>
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<id>urn:sha1:c45647f9f562b52915b43b6bb447827cebf511bd</id>
<content type='text'>
Pull ARM updates from Russell King:

 - Rework phys/virt translation

 - Add KASan support

 - Move DT out of linear map region

 - Use more PC-relative addressing in assembly

 - Remove FP emulation handling while in kernel mode

 - Link with '-z norelro'

 - remove old check for GCC &lt;= 4.2 in ARM unwinder code

 - disable big endian if using clang's linker

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (46 commits)
  ARM: 9027/1: head.S: explicitly map DT even if it lives in the first physical section
  ARM: 9038/1: Link with '-z norelro'
  ARM: 9037/1: uncompress: Add OF_DT_MAGIC macro
  ARM: 9036/1: uncompress: Fix dbgadtb size parameter name
  ARM: 9035/1: uncompress: Add be32tocpu macro
  ARM: 9033/1: arm/smp: Drop the macro S(x,s)
  ARM: 9032/1: arm/mm: Convert PUD level pgtable helper macros into functions
  ARM: 9031/1: hyp-stub: remove unused .L__boot_cpu_mode_offset symbol
  ARM: 9044/1: vfp: use undef hook for VFP support detection
  ARM: 9034/1: __div64_32(): straighten up inline asm constraints
  ARM: 9030/1: entry: omit FP emulation for UND exceptions taken in kernel mode
  ARM: 9029/1: Make iwmmxt.S support Clang's integrated assembler
  ARM: 9028/1: disable KASAN in call stack capturing routines
  ARM: 9026/1: unwind: remove old check for GCC &lt;= 4.2
  ARM: 9025/1: Kconfig: CPU_BIG_ENDIAN depends on !LD_IS_LLD
  ARM: 9024/1: Drop useless cast of "u64" to "long long"
  ARM: 9023/1: Spelling s/mmeory/memory/
  ARM: 9022/1: Change arch/arm/lib/mem*.S to use WEAK instead of .weak
  ARM: kvm: replace open coded VA-&gt;PA calculations with adr_l call
  ARM: head.S: use PC relative insn sequence to calculate PHYS_OFFSET
  ...
</content>
</entry>
<entry>
<title>Merge branch 'devel-stable' into for-next</title>
<updated>2020-12-21T11:19:26Z</updated>
<author>
<name>Russell King</name>
<email>rmk+kernel@armlinux.org.uk</email>
</author>
<published>2020-12-21T11:19:26Z</published>
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<id>urn:sha1:ecbbb88727aee7880527d4b320b4d06dde75d46d</id>
<content type='text'>
</content>
</entry>
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