linux-stable.git/include/asm-generic, branch v5.4.211

locking/atomic: Make test_and_*_bit() ordered on failure

2022-08-25T09:18:31+00:00

commit 415d832497098030241605c52ea83d4e2cfa7879 upstream.

These operations are documented as always ordered in
include/asm-generic/bitops/instrumented-atomic.h, and producer-consumer
type use cases where one side needs to ensure a flag is left pending
after some shared data was updated rely on this ordering, even in the
failure case.

This is the case with the workqueue code, which currently suffers from a
reproducible ordering violation on Apple M1 platforms (which are
notoriously out-of-order) that ends up causing the TTY layer to fail to
deliver data to userspace properly under the right conditions.  This
change fixes that bug.

Change the documentation to restrict the "no order on failure" story to
the _lock() variant (for which it makes sense), and remove the
early-exit from the generic implementation, which is what causes the
missing barrier semantics in that case.  Without this, the remaining
atomic op is fully ordered (including on ARM64 LSE, as of recent
versions of the architecture spec).

Suggested-by: Linus Torvalds 
Cc: stable@vger.kernel.org
Fixes: e986a0d6cb36 ("locking/atomics, asm-generic/bitops/atomic.h: Rewrite using atomic_*() APIs")
Fixes: 61e02392d3c7 ("locking/atomic/bitops: Document and clarify ordering semantics for failed test_and_{}_bit()")
Signed-off-by: Hector Martin 
Acked-by: Will Deacon 
Reviewed-by: Arnd Bergmann 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

tlb: hugetlb: Add more sizes to tlb_remove_huge_tlb_entry

2022-04-20T07:19:37+00:00

[ Upstream commit 697a1d44af8ba0477ee729e632f4ade37999249a ]

tlb_remove_huge_tlb_entry only considers PMD_SIZE and PUD_SIZE when
updating the mmu_gather structure.

Unfortunately on arm64 there are two additional huge page sizes that
need to be covered: CONT_PTE_SIZE and CONT_PMD_SIZE. Where an end-user
attempts to employ contiguous huge pages, a VM_BUG_ON can be experienced
due to the fact that the tlb structure hasn't been correctly updated by
the relevant tlb_flush_p.._range() call from tlb_remove_huge_tlb_entry.

This patch adds inequality logic to the generic implementation of
tlb_remove_huge_tlb_entry s.t. CONT_PTE_SIZE and CONT_PMD_SIZE are
effectively covered on arm64. Also, as well as ptes, pmds and puds;
p4ds are now considered too.

Reported-by: David Hildenbrand 
Suggested-by: Peter Zijlstra (Intel) 
Cc: Anshuman Khandual 
Cc: Catalin Marinas 
Cc: Will Deacon 
Link: https://lore.kernel.org/linux-mm/811c5c8e-b3a2-85d2-049c-717f17c3a03a@redhat.com/
Signed-off-by: Steve Capper 
Acked-by: David Hildenbrand 
Reviewed-by: Anshuman Khandual 
Reviewed-by: Catalin Marinas 
Acked-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/r/20220330112543.863-1-steve.capper@arm.com
Signed-off-by: Will Deacon 
Signed-off-by: Sasha Levin

module/ftrace: handle patchable-function-entry

2022-02-23T10:59:56+00:00

commit a1326b17ac03a9012cb3d01e434aacb4d67a416c upstream.

When using patchable-function-entry, the compiler will record the
callsites into a section named "__patchable_function_entries" rather
than "__mcount_loc". Let's abstract this difference behind a new
FTRACE_CALLSITE_SECTION, so that architectures don't have to handle this
explicitly (e.g. with custom module linker scripts).

As parisc currently handles this explicitly, it is fixed up accordingly,
with its custom linker script removed. Since FTRACE_CALLSITE_SECTION is
only defined when DYNAMIC_FTRACE is selected, the parisc module loading
code is updated to only use the definition in that case. When
DYNAMIC_FTRACE is not selected, modules shouldn't have this section, so
this removes some redundant work in that case.

To make sure that this is keep up-to-date for modules and the main
kernel, a comment is added to vmlinux.lds.h, with the existing ifdeffery
simplified for legibility.

I built parisc generic-{32,64}bit_defconfig with DYNAMIC_FTRACE enabled,
and verified that the section made it into the .ko files for modules.

Signed-off-by: Mark Rutland 
Acked-by: Helge Deller 
Acked-by: Steven Rostedt (VMware) 
Reviewed-by: Ard Biesheuvel 
Reviewed-by: Torsten Duwe 
Tested-by: Amit Daniel Kachhap 
Tested-by: Sven Schnelle 
Tested-by: Torsten Duwe 
Cc: Ingo Molnar 
Cc: James E.J. Bottomley 
Cc: Jessica Yu 
Cc: linux-parisc@vger.kernel.org
Cc: Stephen Boyd 
Signed-off-by: Greg Kroah-Hartman

tlb: mmu_gather: add tlb_flush_*_range APIs

2021-11-26T09:47:23+00:00

commit 2631ed00b0498810f8d5c2163c6b5270d893687b upstream.

tlb_flush_{pte|pmd|pud|p4d}_range() adjust the tlb->start and
tlb->end, then set corresponding cleared_*.

Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Zhenyu Ye 
Acked-by: Catalin Marinas 
Link: https://lore.kernel.org/r/20200625080314.230-5-yezhenyu2@huawei.com
Signed-off-by: Catalin Marinas 
Signed-off-by: Greg Kroah-Hartman

vmlinux.lds.h: Handle clang's module.{c,d}tor sections

2021-08-18T06:57:04+00:00

commit 848378812e40152abe9b9baf58ce2004f76fb988 upstream.

A recent change in LLVM causes module_{c,d}tor sections to appear when
CONFIG_K{A,C}SAN are enabled, which results in orphan section warnings
because these are not handled anywhere:

ld.lld: warning: arch/x86/pci/built-in.a(legacy.o):(.text.asan.module_ctor) is being placed in '.text.asan.module_ctor'
ld.lld: warning: arch/x86/pci/built-in.a(legacy.o):(.text.asan.module_dtor) is being placed in '.text.asan.module_dtor'
ld.lld: warning: arch/x86/pci/built-in.a(legacy.o):(.text.tsan.module_ctor) is being placed in '.text.tsan.module_ctor'

Fangrui explains: "the function asan.module_ctor has the SHF_GNU_RETAIN
flag, so it is in a separate section even with -fno-function-sections
(default)".

Place them in the TEXT_TEXT section so that these technologies continue
to work with the newer compiler versions. All of the KASAN and KCSAN
KUnit tests continue to pass after this change.

Cc: stable@vger.kernel.org
Link: https://github.com/ClangBuiltLinux/linux/issues/1432
Link: https://github.com/llvm/llvm-project/commit/7b789562244ee941b7bf2cefeb3fc08a59a01865
Signed-off-by: Nathan Chancellor 
Reviewed-by: Nick Desaulniers 
Reviewed-by: Fangrui Song 
Acked-by: Marco Elver 
Signed-off-by: Kees Cook 
Link: https://lore.kernel.org/r/20210731023107.1932981-1-nathan@kernel.org
[nc: Resolve conflict due to lack of cf68fffb66d60]
Signed-off-by: Nathan Chancellor 
Signed-off-by: Greg Kroah-Hartman

vmlinux.lds.h: Avoid orphan section with !SMP

2021-06-16T09:59:44+00:00

commit d4c6399900364facd84c9e35ce1540b6046c345f upstream.

With x86_64_defconfig and the following configs, there is an orphan
section warning:

CONFIG_SMP=n
CONFIG_AMD_MEM_ENCRYPT=y
CONFIG_HYPERVISOR_GUEST=y
CONFIG_KVM=y
CONFIG_PARAVIRT=y

ld: warning: orphan section `.data..decrypted' from `arch/x86/kernel/cpu/vmware.o' being placed in section `.data..decrypted'
ld: warning: orphan section `.data..decrypted' from `arch/x86/kernel/kvm.o' being placed in section `.data..decrypted'

These sections are created with DEFINE_PER_CPU_DECRYPTED, which
ultimately turns into __PCPU_ATTRS, which in turn has a section
attribute with a value of PER_CPU_BASE_SECTION + the section name. When
CONFIG_SMP is not set, the base section is .data and that is not
currently handled in any linker script.

Add .data..decrypted to PERCPU_DECRYPTED_SECTION, which is included in
PERCPU_INPUT -> PERCPU_SECTION, which is include in the x86 linker
script when either CONFIG_X86_64 or CONFIG_SMP is unset, taking care of
the warning.

Fixes: ac26963a1175 ("percpu: Introduce DEFINE_PER_CPU_DECRYPTED")
Link: https://github.com/ClangBuiltLinux/linux/issues/1360
Reported-by: kernel test robot 
Signed-off-by: Nathan Chancellor 
Tested-by: Nick Desaulniers  # build
Signed-off-by: Kees Cook 
Link: https://lore.kernel.org/r/20210506001410.1026691-1-nathan@kernel.org
Signed-off-by: Greg Kroah-Hartman

vmlinux.lds.h: add DWARF v5 sections

2021-03-04T09:26:09+00:00

commit 3c4fa46b30c551b1df2fb1574a684f68bc22067c upstream.

We expect toolchains to produce these new debug info sections as part of
DWARF v5. Add explicit placements to prevent the linker warnings from
--orphan-section=warn.

Compilers may produce such sections with explicit -gdwarf-5, or based on
the implicit default version of DWARF when -g is used via DEBUG_INFO.
This implicit default changes over time, and has changed to DWARF v5
with GCC 11.

.debug_sup was mentioned in review, but without compilers producing it
today, let's wait to add it until it becomes necessary.

Cc: stable@vger.kernel.org
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1922707
Reported-by: Chris Murphy 
Suggested-by: Fangrui Song 
Reviewed-by: Nathan Chancellor 
Reviewed-by: Mark Wielaard 
Tested-by: Sedat Dilek 
Signed-off-by: Nick Desaulniers 
Signed-off-by: Masahiro Yamada 
Signed-off-by: Greg Kroah-Hartman

firmware_loader: align .builtin_fw to 8

2021-02-17T09:35:18+00:00

[ Upstream commit 793f49a87aae24e5bcf92ad98d764153fc936570 ]

arm64 references the start address of .builtin_fw (__start_builtin_fw)
with a pair of R_AARCH64_ADR_PREL_PG_HI21/R_AARCH64_LDST64_ABS_LO12_NC
relocations.  The compiler is allowed to emit the
R_AARCH64_LDST64_ABS_LO12_NC relocation because struct builtin_fw in
include/linux/firmware.h is 8-byte aligned.

The R_AARCH64_LDST64_ABS_LO12_NC relocation requires the address to be a
multiple of 8, which may not be the case if .builtin_fw is empty.
Unconditionally align .builtin_fw to fix the linker error.  32-bit
architectures could use ALIGN(4) but that would add unnecessary
complexity, so just use ALIGN(8).

Link: https://lkml.kernel.org/r/20201208054646.2913063-1-maskray@google.com
Link: https://github.com/ClangBuiltLinux/linux/issues/1204
Fixes: 5658c76 ("firmware: allow firmware files to be built into kernel image")
Signed-off-by: Fangrui Song 
Reported-by: kernel test robot 
Acked-by: Arnd Bergmann 
Reviewed-by: Nick Desaulniers 
Tested-by: Nick Desaulniers 
Tested-by: Douglas Anderson 
Acked-by: Nathan Chancellor 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

vmlinux.lds.h: Create section for protection against instrumentation

2021-02-17T09:35:16+00:00

[ Upstream commit 6553896666433e7efec589838b400a2a652b3ffa ]

Some code pathes, especially the low level entry code, must be protected
against instrumentation for various reasons:

 - Low level entry code can be a fragile beast, especially on x86.

 - With NO_HZ_FULL RCU state needs to be established before using it.

Having a dedicated section for such code allows to validate with tooling
that no unsafe functions are invoked.

Add the .noinstr.text section and the noinstr attribute to mark
functions. noinstr implies notrace. Kprobes will gain a section check
later.

Provide also a set of markers: instrumentation_begin()/end()

These are used to mark code inside a noinstr function which calls
into regular instrumentable text section as safe.

The instrumentation markers are only active when CONFIG_DEBUG_ENTRY is
enabled as the end marker emits a NOP to prevent the compiler from merging
the annotation points. This means the objtool verification requires a
kernel compiled with this option.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Alexandre Chartre 
Acked-by: Peter Zijlstra 
Link: https://lkml.kernel.org/r/20200505134100.075416272@linutronix.de
Signed-off-by: Sasha Levin

arm64: make atomic helpers __always_inline

2021-01-27T10:47:44+00:00

[ Upstream commit c35a824c31834d947fb99b0c608c1b9f922b4ba0 ]

With UBSAN enabled and building with clang, there are occasionally
warnings like

WARNING: modpost: vmlinux.o(.text+0xc533ec): Section mismatch in reference from the function arch_atomic64_or() to the variable .init.data:numa_nodes_parsed
The function arch_atomic64_or() references
the variable __initdata numa_nodes_parsed.
This is often because arch_atomic64_or lacks a __initdata
annotation or the annotation of numa_nodes_parsed is wrong.

for functions that end up not being inlined as intended but operating
on __initdata variables. Mark these as __always_inline, along with
the corresponding asm-generic wrappers.

Signed-off-by: Arnd Bergmann 
Acked-by: Will Deacon 
Link: https://lore.kernel.org/r/20210108092024.4034860-1-arnd@kernel.org
Signed-off-by: Catalin Marinas 
Signed-off-by: Sasha Levin