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SVE has been public for some time now. Let the decoder acknowledge
its existence.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Link: https://lore.kernel.org/r/20210303170536.1838032-6-jthierry@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>
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Aarch64 instruction set encoding and decoding logic can prove useful
for some features/tools both part of the kernel and outside the kernel.
Isolate the function dealing only with encoding/decoding instructions,
with minimal dependency on kernel utilities in order to be able to reuse
that code.
Code was only moved, no code should have been added, removed nor
modifier.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Link: https://lore.kernel.org/r/20210303170536.1838032-5-jthierry@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>
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By using outlined checks we can achieve a significant code size
improvement by moving the tag-based ASAN checks into separate
functions. Unlike the existing CONFIG_KASAN_OUTLINE mode these
functions have a custom calling convention that preserves most
registers and is specialized to the register containing the address
and the type of access, and as a result we can eliminate the code
size and performance overhead of a standard calling convention such
as AAPCS for these functions.
This change depends on a separate series of changes to Clang [1] to
support outlined checks in the kernel, although the change works fine
without them (we just don't get outlined checks). This is because the
flag -mllvm -hwasan-inline-all-checks=0 has no effect until the Clang
changes land. The flag was introduced in the Clang 9.0 timeframe as
part of the support for outlined checks in userspace and because our
minimum Clang version is 10.0 we can pass it unconditionally.
Outlined checks require a new runtime function with a custom calling
convention. Add this function to arch/arm64/lib.
I measured the code size of defconfig + tag-based KASAN, as well
as boot time (i.e. time to init launch) on a DragonBoard 845c with
an Android arm64 GKI kernel. The results are below:
code size boot time
CONFIG_KASAN_INLINE=y before 92824064 6.18s
CONFIG_KASAN_INLINE=y after 38822400 6.65s
CONFIG_KASAN_OUTLINE=y 39215616 11.48s
We can see straight away that specialized outlined checks beat the
existing CONFIG_KASAN_OUTLINE=y on both code size and boot time
for tag-based ASAN.
As for the comparison between CONFIG_KASAN_INLINE=y before and after
we saw similar performance numbers in userspace [2] and decided
that since the performance overhead is minimal compared to the
overhead of tag-based ASAN itself as well as compared to the code
size improvements we would just replace the inlined checks with the
specialized outlined checks without the option to select between them,
and that is what I have implemented in this patch.
Signed-off-by: Peter Collingbourne <pcc@google.com>
Acked-by: Andrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://linux-review.googlesource.com/id/I1a30036c70ab3c3ee78d75ed9b87ef7cdc3fdb76
Link: [1] https://reviews.llvm.org/D90426
Link: [2] https://reviews.llvm.org/D56954
Link: https://lore.kernel.org/r/20210526174927.2477847-3-pcc@google.com
Signed-off-by: Will Deacon <will@kernel.org>
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Although naming across the codebase isn't that consistent, it
tends to follow certain patterns. Moreover, the term "flush"
isn't defined in the Arm Architecture reference manual, and might
be interpreted to mean clean, invalidate, or both for a cache.
Rename arm64-internal functions to make the naming internally
consistent, as well as making it consistent with the Arm ARM, by
specifying whether it applies to the instruction, data, or both
caches, whether the operation is a clean, invalidate, or both.
Also specify which point the operation applies to, i.e., to the
point of unification (PoU), coherency (PoC), or persistence
(PoP).
This commit applies the following sed transformation to all files
under arch/arm64:
"s/\b__flush_cache_range\b/caches_clean_inval_pou_macro/g;"\
"s/\b__flush_icache_range\b/caches_clean_inval_pou/g;"\
"s/\binvalidate_icache_range\b/icache_inval_pou/g;"\
"s/\b__flush_dcache_area\b/dcache_clean_inval_poc/g;"\
"s/\b__inval_dcache_area\b/dcache_inval_poc/g;"\
"s/__clean_dcache_area_poc\b/dcache_clean_poc/g;"\
"s/\b__clean_dcache_area_pop\b/dcache_clean_pop/g;"\
"s/\b__clean_dcache_area_pou\b/dcache_clean_pou/g;"\
"s/\b__flush_cache_user_range\b/caches_clean_inval_user_pou/g;"\
"s/\b__flush_icache_all\b/icache_inval_all_pou/g;"
Note that __clean_dcache_area_poc is deliberately missing a word
boundary check at the beginning in order to match the efistub
symbols in image-vars.h.
Also note that, despite its name, __flush_icache_range operates
on both instruction and data caches. The name change here
reflects that.
No functional change intended.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20210524083001.2586635-19-tabba@google.com
Signed-off-by: Will Deacon <will@kernel.org>
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To be consistent with other functions with similar names and
functionality in cacheflush.h, cache.S, and cachetlb.rst, change
to specify the range in terms of start and end, as opposed to
start and size.
No functional change intended.
Reported-by: Will Deacon <will@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20210524083001.2586635-15-tabba@google.com
Signed-off-by: Will Deacon <will@kernel.org>
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clear_page() and copy_page() are suitable for use outside of the kernel
address space, so annotate them as position-independent code.
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-2-qperret@google.com
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This change provides a simpler implementation of mte_get_mem_tag(),
mte_get_random_tag(), and mte_set_mem_tag_range().
Simplifications include removing system_supports_mte() checks as these
functions are onlye called from KASAN runtime that had already checked
system_supports_mte(). Besides that, size and address alignment checks
are removed from mte_set_mem_tag_range(), as KASAN now does those.
This change also moves these functions into the asm/mte-kasan.h header and
implements mte_set_mem_tag_range() via inline assembly to avoid
unnecessary functions calls.
[vincenzo.frascino@arm.com: fix warning in mte_get_random_tag()]
Link: https://lkml.kernel.org/r/20210211152208.23811-1-vincenzo.frascino@arm.com
Link: https://lkml.kernel.org/r/a26121b294fdf76e369cb7a74351d1c03a908930.1612546384.git.andreyknvl@google.com
Co-developed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Provide helper functions to manipulate allocation and pointer tags for
kernel addresses.
Low-level helper functions (mte_assign_*, written in assembly) operate tag
values from the [0x0, 0xF] range. High-level helper functions
(mte_get/set_*) use the [0xF0, 0xFF] range to preserve compatibility with
normal kernel pointers that have 0xFF in their top byte.
MTE_GRANULE_SIZE and related definitions are moved to mte-def.h header
that doesn't have any dependencies and is safe to include into any
low-level header.
Link: https://lkml.kernel.org/r/c31bf759b4411b2d98cdd801eb928e241584fd1f.1606161801.git.andreyknvl@google.com
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Co-developed-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Now the uaccess primitives use LDTR/STTR unconditionally, the
uao_{ldp,stp,user_alternative} asm macros are misnamed, and have a
redundant argument. Let's remove the redundant argument and rename these
to user_{ldp,stp,ldst} respectively to clean this up.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Robin Murohy <robin.murphy@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201202131558.39270-9-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Currently __copy_user_flushcache() open-codes raw_copy_from_user(), and
doesn't use uaccess_mask_ptr() on the user address. Let's have it call
raw_copy_from_user(), which is both a simplification and ensures that
user pointers are masked under speculation.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201202131558.39270-6-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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The uao_* alternative asm macros are only used by the uaccess assembly
routines in arch/arm64/lib/, where they are included indirectly via
asm-uaccess.h. Since they're specific to the uaccess assembly (and will
lose the alternatives in subsequent patches), let's move them into
asm-uaccess.h.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
[will: update #include in mte.S to pull in uao asm macros]
Signed-off-by: Will Deacon <will@kernel.org>
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Commit 39d114ddc682 ("arm64: add KASAN support") added .weak directives to
arch/arm64/lib/mem*.S instead of changing the existing SYM_FUNC_START_PI
macros. This can lead to the assembly snippet `.weak memcpy ... .globl
memcpy` which will produce a STB_WEAK memcpy with GNU as but STB_GLOBAL
memcpy with LLVM's integrated assembler before LLVM 12. LLVM 12 (since
https://reviews.llvm.org/D90108) will error on such an overridden symbol
binding.
Use the appropriate SYM_FUNC_START_WEAK_PI instead.
Fixes: 39d114ddc682 ("arm64: add KASAN support")
Reported-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Fangrui Song <maskray@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20201029181951.1866093-1-maskray@google.com
Signed-off-by: Will Deacon <will@kernel.org>
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When swapping pages out to disk it is necessary to save any tags that
have been set, and restore when swapping back in. Make use of the new
page flag (PG_ARCH_2, locally named PG_mte_tagged) to identify pages
with tags. When swapping out these pages the tags are stored in memory
and later restored when the pages are brought back in. Because shmem can
swap pages back in without restoring the userspace PTE it is also
necessary to add a hook for shmem.
Signed-off-by: Steven Price <steven.price@arm.com>
[catalin.marinas@arm.com: move function prototypes to mte.h]
[catalin.marinas@arm.com: drop '_tags' from arch_swap_restore_tags()]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Will Deacon <will@kernel.org>
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Add support for bulk setting/getting of the MTE tags in a tracee's
address space at 'addr' in the ptrace() syscall prototype. 'data' points
to a struct iovec in the tracer's address space with iov_base
representing the address of a tracer's buffer of length iov_len. The
tags to be copied to/from the tracer's buffer are stored as one tag per
byte.
On successfully copying at least one tag, ptrace() returns 0 and updates
the tracer's iov_len with the number of tags copied. In case of error,
either -EIO or -EFAULT is returned, trying to follow the ptrace() man
page.
Note that the tag copying functions are not performance critical,
therefore they lack optimisations found in typical memory copy routines.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Alan Hayward <Alan.Hayward@arm.com>
Cc: Luis Machado <luis.machado@linaro.org>
Cc: Omair Javaid <omair.javaid@linaro.org>
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When the Memory Tagging Extension is enabled, the tags need to be
preserved across page copy (e.g. for copy-on-write, page migration).
Introduce MTE-aware copy_{user_,}highpage() functions to copy tags to
the destination if the source page has the PG_mte_tagged flag set.
copy_user_page() does not need to handle tag copying since, with this
patch, it is only called by the DAX code where there is no source page
structure (and no source tags).
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Co-developed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
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Pages allocated by the kernel are not guaranteed to have the tags
zeroed, especially as the kernel does not (yet) use MTE itself. To
ensure the user can still access such pages when mapped into its address
space, clear the tags via set_pte_at(). A new page flag - PG_mte_tagged
(PG_arch_2) - is used to track pages with valid allocation tags.
Since the zero page is mapped as pte_special(), it won't be covered by
the above set_pte_at() mechanism. Clear its tags during early MTE
initialisation.
Co-developed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/will/linux
Pull READ/WRITE_ONCE rework from Will Deacon:
"This the READ_ONCE rework I've been working on for a while, which
bumps the minimum GCC version and improves code-gen on arm64 when
stack protector is enabled"
[ Side note: I'm _really_ tempted to raise the minimum gcc version to
4.9, so that we can just say that we require _Generic() support.
That would allow us to more cleanly handle a lot of the cases where we
depend on very complex macros with 'sizeof' or __builtin_choose_expr()
with __builtin_types_compatible_p() etc.
This branch has a workaround for sparse not handling _Generic(),
either, but that was already fixed in the sparse development branch,
so it's really just gcc-4.9 that we'd require. - Linus ]
* 'rwonce/rework' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux:
compiler_types.h: Use unoptimized __unqual_scalar_typeof for sparse
compiler_types.h: Optimize __unqual_scalar_typeof compilation time
compiler.h: Enforce that READ_ONCE_NOCHECK() access size is sizeof(long)
compiler-types.h: Include naked type in __pick_integer_type() match
READ_ONCE: Fix comment describing 2x32-bit atomicity
gcov: Remove old GCC 3.4 support
arm64: barrier: Use '__unqual_scalar_typeof' for acquire/release macros
locking/barriers: Use '__unqual_scalar_typeof' for load-acquire macros
READ_ONCE: Drop pointer qualifiers when reading from scalar types
READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses
READ_ONCE: Simplify implementations of {READ,WRITE}_ONCE()
arm64: csum: Disable KASAN for do_csum()
fault_inject: Don't rely on "return value" from WRITE_ONCE()
net: tls: Avoid assigning 'const' pointer to non-const pointer
netfilter: Avoid assigning 'const' pointer to non-const pointer
compiler/gcc: Raise minimum GCC version for kernel builds to 4.8
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The current argument order is obviously buggy (memcpy.S):
macro strb1 ptr, regB, val
strb \ptr, [\regB], \val
endm
However, it cancels out as the calling sites in copy_template.S pass the
address as the regB argument.
Mechanically reorder the arguments to match the instruction mnemonics.
There is no difference in objdump before and after this patch.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20200429183702.28445-1-catalin.marinas@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
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Currently most of the assembly files that use architecture extensions
enable them using the .arch directive but crc32.S uses .cpu instead. Move
that over to .arch for consistency.
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20200414182843.31664-1-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
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do_csum() over-reads the source buffer and therefore abuses
READ_ONCE_NOCHECK() to avoid tripping up KASAN. In preparation for
READ_ONCE_NOCHECK() becoming a macro, and therefore losing its
'__no_sanitize_address' annotation, just annotate do_csum() explicitly
and fall back to normal loads.
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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There is a spelling mistake in the comment, Fix it.
Signed-off-by: hankecai <hankecai@bbktel.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Throwing our __uint128_t idioms at csum_ipv6_magic() makes it
about 1.3x-2x faster across a range of microarchitecture/compiler
combinations. Not much in absolute terms, but every little helps.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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* for-next/asm-annotations: (6 commits)
arm64: kernel: Correct annotation of end of el0_sync
...
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'for-next/e0pd', 'for-next/entry', 'for-next/kbuild', 'for-next/kexec/cleanup', 'for-next/kexec/file-kdump', 'for-next/misc', 'for-next/nofpsimd', 'for-next/perf' and 'for-next/scs' into for-next/core
* for-next/acpi:
ACPI/IORT: Fix 'Number of IDs' handling in iort_id_map()
* for-next/cpufeatures: (2 commits)
arm64: Introduce ID_ISAR6 CPU register
...
* for-next/csum: (2 commits)
arm64: csum: Fix pathological zero-length calls
...
* for-next/e0pd: (7 commits)
arm64: kconfig: Fix alignment of E0PD help text
...
* for-next/entry: (5 commits)
arm64: entry: cleanup sp_el0 manipulation
...
* for-next/kbuild: (4 commits)
arm64: kbuild: remove compressed images on 'make ARCH=arm64 (dist)clean'
...
* for-next/kexec/cleanup: (11 commits)
Revert "arm64: kexec: make dtb_mem always enabled"
...
* for-next/kexec/file-kdump: (2 commits)
arm64: kexec_file: add crash dump support
...
* for-next/misc: (12 commits)
arm64: entry: Avoid empty alternatives entries
...
* for-next/nofpsimd: (7 commits)
arm64: nofpsmid: Handle TIF_FOREIGN_FPSTATE flag cleanly
...
* for-next/perf: (2 commits)
perf/imx_ddr: Fix cpu hotplug state cleanup
...
* for-next/scs: (6 commits)
arm64: kernel: avoid x18 in __cpu_soft_restart
...
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In validating the checksumming results of the new routine, I sadly
neglected to test its not-checksumming results. Thus it slipped through
that the one case where @buff is already dword-aligned and @len = 0
manages to defeat the tail-masking logic and behave as if @len = 8.
For a zero length it doesn't make much sense to deference @buff anyway,
so just add an early return (which has essentially zero impact on
performance).
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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Register x18 will no longer be used as a caller save register in the
future, so stop using it in the copy_page() code.
Link: https://patchwork.kernel.org/patch/9836869/
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
[Sami: changed the offset and bias to be explicit]
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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Apparently there exist certain workloads which rely heavily on software
checksumming, for which the generic do_csum() implementation becomes a
significant bottleneck. Therefore let's give arm64 its own optimised
version - for ease of maintenance this foregoes assembly or intrisics,
and is thus not actually arm64-specific, but does rely heavily on C
idioms that translate well to the A64 ISA and the typical load/store
capabilities of most ARMv8 CPU cores.
The resulting increase in checksum throughput scales nicely with buffer
size, tending towards 4x for a small in-order core (Cortex-A53), and up
to 6x or more for an aggressive big core (Ampere eMAG).
Reported-by: Lingyan Huang <huanglingyan2@huawei.com>
Tested-by: Lingyan Huang <huanglingyan2@huawei.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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In an effort to clarify and simplify the annotation of assembly functions
in the kernel new macros have been introduced. These replace ENTRY and
ENDPROC and also add a new annotation for static functions which previously
had no ENTRY equivalent. Update the annotations in the library code to the
new macros.
Signed-off-by: Mark Brown <broonie@kernel.org>
[will: Use SYM_FUNC_START_WEAK_PI]
Signed-off-by: Will Deacon <will@kernel.org>
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It is safer and simpler to drop the uaccess assembly macros in favour of
inline C functions. Although this bloats the Image size slightly, it
aligns our user copy routines with '{get,put}_user()' and generally
makes the code a lot easier to reason about.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
[will: tweaked commit message and changed temporary variable names]
Signed-off-by: Will Deacon <will@kernel.org>
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A number of our uaccess routines ('__arch_clear_user()' and
'__arch_copy_{in,from,to}_user()') fail to re-enable PAN if they
encounter an unhandled fault whilst accessing userspace.
For CPUs implementing both hardware PAN and UAO, this bug has no effect
when both extensions are in use by the kernel.
For CPUs implementing hardware PAN but not UAO, this means that a kernel
using hardware PAN may execute portions of code with PAN inadvertently
disabled, opening us up to potential security vulnerabilities that rely
on userspace access from within the kernel which would usually be
prevented by this mechanism. In other words, parts of the kernel run the
same way as they would on a CPU without PAN implemented/emulated at all.
For CPUs not implementing hardware PAN and instead relying on software
emulation via 'CONFIG_ARM64_SW_TTBR0_PAN=y', the impact is unfortunately
much worse. Calling 'schedule()' with software PAN disabled means that
the next task will execute in the kernel using the page-table and ASID
of the previous process even after 'switch_mm()', since the actual
hardware switch is deferred until return to userspace. At this point, or
if there is a intermediate call to 'uaccess_enable()', the page-table
and ASID of the new process are installed. Sadly, due to the changes
introduced by KPTI, this is not an atomic operation and there is a very
small window (two instructions) where the CPU is configured with the
page-table of the old task and the ASID of the new task; a speculative
access in this state is disastrous because it would corrupt the TLB
entries for the new task with mappings from the previous address space.
As Pavel explains:
| I was able to reproduce memory corruption problem on Broadcom's SoC
| ARMv8-A like this:
|
| Enable software perf-events with PERF_SAMPLE_CALLCHAIN so userland's
| stack is accessed and copied.
|
| The test program performed the following on every CPU and forking
| many processes:
|
| unsigned long *map = mmap(NULL, PAGE_SIZE, PROT_READ|PROT_WRITE,
| MAP_SHARED | MAP_ANONYMOUS, -1, 0);
| map[0] = getpid();
| sched_yield();
| if (map[0] != getpid()) {
| fprintf(stderr, "Corruption detected!");
| }
| munmap(map, PAGE_SIZE);
|
| From time to time I was getting map[0] to contain pid for a
| different process.
Ensure that PAN is re-enabled when returning after an unhandled user
fault from our uaccess routines.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Cc: <stable@vger.kernel.org>
Fixes: 338d4f49d6f7 ("arm64: kernel: Add support for Privileged Access Never")
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
[will: rewrote commit message]
Signed-off-by: Will Deacon <will@kernel.org>
|
|
* for-next/atomics: (10 commits)
Rework LSE instruction selection to use static keys instead of alternatives
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|
We no longer fall back to out-of-line atomics on systems with
CONFIG_ARM64_LSE_ATOMICS where ARM64_HAS_LSE_ATOMICS is not set.
Remove the unused compilation unit which provided these symbols.
Signed-off-by: Andrew Murray <andrew.murray@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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|
Inspired by the commit 7cd01b08d35f ("powerpc: Add support for function
error injection"), this patch supports function error injection for
Arm64.
This patch mainly support two functions: one is regs_set_return_value()
which is used to overwrite the return value; the another function is
override_function_with_return() which is to override the probed
function returning and jump to its caller.
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Will Deacon <will@kernel.org>
|
|
Based on 2 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 4122 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not see http www gnu org
licenses
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 503 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Enrico Weigelt <info@metux.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
In preparation for arm64 supporting ftrace built on other compiler
options, let's have the arm64 Makefiles remove the $(CC_FLAGS_FTRACE)
flags, whatever these may be, rather than assuming '-pg'.
There should be no functional change as a result of this patch.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Torsten Duwe <duwe@suse.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>
|
|
For a while now it's been possible to use EXPORT_SYMBOL() in assembly
files, which allows us to place exports immediately after assembly
functions, as we do for C functions.
As a step towards removing arm64ksyms.c, let's move the string routine
exports to the assembly files the functions are defined in. Routines
which should only be exported for !KASAN builds are exported using the
EXPORT_SYMBOL_NOKASAN() helper.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
|
|
For a while now it's been possible to use EXPORT_SYMBOL() in assembly
files, which allows us to place exports immediately after assembly
functions, as we do for C functions.
As a step towards removing arm64ksyms.c, let's move the uaccess exports
to the assembly files the functions are defined in. As we have to
include <asm/assembler.h>, the existing includes are fixed to follow the
usual ordering conventions.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
|
|
For a while now it's been possible to use EXPORT_SYMBOL() in assembly
files, which allows us to place exports immediately after assembly
functions, as we do for C functions.
As a step towards removing arm64ksyms.c, let's move the copy_page and
clear_page exports to the assembly files the functions are defined in.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
|
|
For a while now it's been possible to use EXPORT_SYMBOL() in assembly
files, which allows us to place exports immediately after assembly
functions, as we do for C functions.
As a step towards removing arm64ksyms.c, let's move the tishift exports
to the assembly file the functions are defined in.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
|
|
This is a NEON acceleration method that can improve
performance by approximately 20%. I got the following
data from the centos 7.5 on Huawei's HISI1616 chip:
[ 93.837726] xor: measuring software checksum speed
[ 93.874039] 8regs : 7123.200 MB/sec
[ 93.914038] 32regs : 7180.300 MB/sec
[ 93.954043] arm64_neon: 9856.000 MB/sec
[ 93.954047] xor: using function: arm64_neon (9856.000 MB/sec)
I believe this code can bring some optimization for
all arm64 platform. thanks for Ard Biesheuvel's suggestions.
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
|
|
Improve the performance of the crc32() asm routines by getting rid of
most of the branches and small sized loads on the common path.
Instead, use a branchless code path involving overlapping 16 byte
loads to process the first (length % 32) bytes, and process the
remainder using a loop that processes 32 bytes at a time.
Tested using the following test program:
#include <stdlib.h>
extern void crc32_le(unsigned short, char const*, int);
int main(void)
{
static const char buf[4096];
srand(20181126);
for (int i = 0; i < 100 * 1000 * 1000; i++)
crc32_le(0, buf, rand() % 1024);
return 0;
}
On Cortex-A53 and Cortex-A57, the performance regresses but only very
slightly. On Cortex-A72 however, the performance improves from
$ time ./crc32
real 0m10.149s
user 0m10.149s
sys 0m0.000s
to
$ time ./crc32
real 0m7.915s
user 0m7.915s
sys 0m0.000s
Cc: Rui Sun <sunrui26@huawei.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
|
|
ARM64 has asm implementation of memchr(), memcmp(), str[r]chr(),
str[n]cmp(), str[n]len(). KASAN don't see memory accesses in asm code,
thus it can potentially miss many bugs.
Ifdef out __HAVE_ARCH_* defines of these functions when KASAN is enabled,
so the generic implementations from lib/string.c will be used.
We can't just remove the asm functions because efistub uses them. And we
can't have two non-weak functions either, so declare the asm functions as
weak.
Link: http://lkml.kernel.org/r/20180920135631.23833-2-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: Kyeongdon Kim <kyeongdon.kim@lge.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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x0 is not callee-saved in the PCS. So there is no need to specify
-fcall-used-x0.
Clang doesn't currently support -fcall-used flags. This patch will help
building the kernel with clang.
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Tri Vo <trong@android.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
|
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Unlike crc32c(), which is wired up to the crypto API internally so the
optimal driver is selected based on the platform's capabilities,
crc32_le() is implemented as a library function using a slice-by-8 table
based C implementation. Even though few of the call sites may be
bottlenecks, calling a time variant implementation with a non-negligible
D-cache footprint is a bit of a waste, given that ARMv8.1 and up mandates
support for the CRC32 instructions that were optional in ARMv8.0, but are
already widely available, even on the Cortex-A53 based Raspberry Pi.
So implement routines that use these instructions if available, and fall
back to the existing generic routines otherwise. The selection is based
on alternatives patching.
Note that this unconditionally selects CONFIG_CRC32 as a builtin. Since
CRC32 is relied upon by core functionality such as CONFIG_OF_FLATTREE,
this just codifies the status quo.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
|
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asm-generic
The <asm-generic/bitops/{atomic,lock}.h> implementations are built around
the atomic-fetch ops, which we implement efficiently for both LSE and
LL/SC systems. Use that instead of our hand-rolled, out-of-line bitops.S.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: yamada.masahiro@socionext.com
Link: https://lore.kernel.org/lkml/1529412794-17720-9-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Otherwise modules that use these arithmetic operations will fail to
link. We accomplish this with the usual EXPORT_SYMBOL, which on most
architectures goes in the .S file but the ARM64 maintainers prefer that
insead it goes into arm64ksyms.
While we're at it, we also fix this up to use SPDX, and I personally
choose to relicense this as GPL2||BSD so that these symbols don't need
to be export_symbol_gpl, so all modules can use the routines, since
these are important general purpose compiler-generated function calls.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reported-by: PaX Team <pageexec@freemail.hu>
Cc: stable@vger.kernel.org
Signed-off-by: Will Deacon <will.deacon@arm.com>
|
|
Our out-of-line atomics are built with a special calling convention,
preventing pointless stack spilling, and allowing us to patch call sites
with ARMv8.1 atomic instructions.
Instrumentation inserted by the compiler may result in calls to
functions not following this special calling convention, resulting in
registers being unexpectedly clobbered, and various problems resulting
from this.
For example, if a kernel is built with KCOV and ARM64_LSE_ATOMICS, the
compiler inserts calls to __sanitizer_cov_trace_pc in the prologues of
the atomic functions. This has been observed to result in spurious
cmpxchg failures, leading to a hang early on in the boot process.
This patch avoids such issues by preventing instrumentation of our
out-of-line atomics.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux
Pull DeviceTree updates from Rob Herring:
- Sync dtc to upstream version v1.4.6-9-gaadd0b65c987. This adds a
bunch more warnings (hidden behind W=1).
- Build dtc lexer and parser files instead of using shipped versions.
- Rework overlay apply API to take an FDT as input and apply overlays
in a single step.
- Add a phandle lookup cache. This improves boot time by hundreds of
msec on systems with large DT.
- Add trivial mcp4017/18/19 potentiometers bindings.
- Remove VLA stack usage in DT code.
* tag 'devicetree-for-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (26 commits)
of: unittest: fix an error code in of_unittest_apply_overlay()
of: unittest: move misplaced function declaration
of: unittest: Remove VLA stack usage
of: overlay: Fix forgotten reference to of_overlay_apply()
of: Documentation: Fix forgotten reference to of_overlay_apply()
of: unittest: local return value variable related cleanups
of: unittest: remove unneeded local return value variables
dt-bindings: trivial: add various mcp4017/18/19 potentiometers
of: unittest: fix an error test in of_unittest_overlay_8()
of: cache phandle nodes to reduce cost of of_find_node_by_phandle()
dt-bindings: rockchip-dw-mshc: use consistent clock names
MAINTAINERS: Add linux/of_*.h headers to appropriate subsystems
scripts: turn off some new dtc warnings by default
scripts/dtc: Update to upstream version v1.4.6-9-gaadd0b65c987
scripts/dtc: generate lexer and parser during build instead of shipping
powerpc: boot: add strrchr function
of: overlay: do not include path in full_name of added nodes
of: unittest: clean up changeset test
arm64/efi: Make strrchr() available to the EFI namespace
ARM: boot: add strrchr function
...
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|
In cases where x30 is used as a temporary in the out-of-line ll/sc atomics
(e.g. atomic_fetch_add), the compiler tends to put out a full stackframe,
which included pointing the x29 at the new frame.
Since these things aren't traceable anyway, we can pass -fomit-frame-pointer
to reduce the work when spilling. Since this is incompatible with -pg, we
also remove that from the CFLAGS for this file.
Signed-off-by: Will Deacon <will.deacon@arm.com>
|
