<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/arch/arm64/lib, branch v5.17</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge branches 'for-next/misc', 'for-next/cache-ops-dzp', 'for-next/stacktrace', 'for-next/xor-neon', 'for-next/kasan', 'for-next/armv8_7-fp', 'for-next/atomics', 'for-next/bti', 'for-next/sve', 'for-next/kselftest' and 'for-next/kcsan', remote-tracking branch 'arm64/for-next/perf' into for-next/core</title>
<updated>2022-01-05T18:14:32+00:00</updated>
<author>
<name>Catalin Marinas</name>
<email>catalin.marinas@arm.com</email>
</author>
<published>2022-01-05T18:14:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=945409a6ef442cfe5f2f14e5626d4306d53100f0'/>
<id>945409a6ef442cfe5f2f14e5626d4306d53100f0</id>
<content type='text'>
* arm64/for-next/perf: (32 commits)
  arm64: perf: Don't register user access sysctl handler multiple times
  drivers: perf: marvell_cn10k: fix an IS_ERR() vs NULL check
  perf/smmuv3: Fix unused variable warning when CONFIG_OF=n
  arm64: perf: Support new DT compatibles
  arm64: perf: Simplify registration boilerplate
  arm64: perf: Support Denver and Carmel PMUs
  drivers/perf: hisi: Add driver for HiSilicon PCIe PMU
  docs: perf: Add description for HiSilicon PCIe PMU driver
  dt-bindings: perf: Add YAML schemas for Marvell CN10K LLC-TAD pmu bindings
  drivers: perf: Add LLC-TAD perf counter support
  perf/smmuv3: Synthesize IIDR from CoreSight ID registers
  perf/smmuv3: Add devicetree support
  dt-bindings: Add Arm SMMUv3 PMCG binding
  perf/arm-cmn: Add debugfs topology info
  perf/arm-cmn: Add CI-700 Support
  dt-bindings: perf: arm-cmn: Add CI-700
  perf/arm-cmn: Support new IP features
  perf/arm-cmn: Demarcate CMN-600 specifics
  perf/arm-cmn: Move group validation data off-stack
  perf/arm-cmn: Optimise DTC counter accesses
  ...

* for-next/misc:
  : Miscellaneous patches
  arm64: Use correct method to calculate nomap region boundaries
  arm64: Drop outdated links in comments
  arm64: errata: Fix exec handling in erratum 1418040 workaround
  arm64: Unhash early pointer print plus improve comment
  asm-generic: introduce io_stop_wc() and add implementation for ARM64
  arm64: remove __dma_*_area() aliases
  docs/arm64: delete a space from tagged-address-abi
  arm64/fp: Add comments documenting the usage of state restore functions
  arm64: mm: Use asid feature macro for cheanup
  arm64: mm: Rename asid2idx() to ctxid2asid()
  arm64: kexec: reduce calls to page_address()
  arm64: extable: remove unused ex_handler_t definition
  arm64: entry: Use SDEI event constants
  arm64: Simplify checking for populated DT
  arm64/kvm: Fix bitrotted comment for SVE handling in handle_exit.c

* for-next/cache-ops-dzp:
  : Avoid DC instructions when DCZID_EL0.DZP == 1
  arm64: mte: DC {GVA,GZVA} shouldn't be used when DCZID_EL0.DZP == 1
  arm64: clear_page() shouldn't use DC ZVA when DCZID_EL0.DZP == 1

* for-next/stacktrace:
  : Unify the arm64 unwind code
  arm64: Make some stacktrace functions private
  arm64: Make dump_backtrace() use arch_stack_walk()
  arm64: Make profile_pc() use arch_stack_walk()
  arm64: Make return_address() use arch_stack_walk()
  arm64: Make __get_wchan() use arch_stack_walk()
  arm64: Make perf_callchain_kernel() use arch_stack_walk()
  arm64: Mark __switch_to() as __sched
  arm64: Add comment for stack_info::kr_cur
  arch: Make ARCH_STACKWALK independent of STACKTRACE

* for-next/xor-neon:
  : Use SHA3 instructions to speed up XOR
  arm64/xor: use EOR3 instructions when available

* for-next/kasan:
  : Log potential KASAN shadow aliases
  arm64: mm: log potential KASAN shadow alias
  arm64: mm: use die_kernel_fault() in do_mem_abort()

* for-next/armv8_7-fp:
  : Add HWCAPS for ARMv8.7 FEAT_AFP amd FEAT_RPRES
  arm64: cpufeature: add HWCAP for FEAT_RPRES
  arm64: add ID_AA64ISAR2_EL1 sys register
  arm64: cpufeature: add HWCAP for FEAT_AFP

* for-next/atomics:
  : arm64 atomics clean-ups and codegen improvements
  arm64: atomics: lse: define RETURN ops in terms of FETCH ops
  arm64: atomics: lse: improve constraints for simple ops
  arm64: atomics: lse: define ANDs in terms of ANDNOTs
  arm64: atomics lse: define SUBs in terms of ADDs
  arm64: atomics: format whitespace consistently

* for-next/bti:
  : BTI clean-ups
  arm64: Ensure that the 'bti' macro is defined where linkage.h is included
  arm64: Use BTI C directly and unconditionally
  arm64: Unconditionally override SYM_FUNC macros
  arm64: Add macro version of the BTI instruction
  arm64: ftrace: add missing BTIs
  arm64: kexec: use __pa_symbol(empty_zero_page)
  arm64: update PAC description for kernel

* for-next/sve:
  : SVE code clean-ups and refactoring in prepararation of Scalable Matrix Extensions
  arm64/sve: Minor clarification of ABI documentation
  arm64/sve: Generalise vector length configuration prctl() for SME
  arm64/sve: Make sysctl interface for SVE reusable by SME

* for-next/kselftest:
  : arm64 kselftest additions
  kselftest/arm64: Add pidbench for floating point syscall cases
  kselftest/arm64: Add a test program to exercise the syscall ABI
  kselftest/arm64: Allow signal tests to trigger from a function
  kselftest/arm64: Parameterise ptrace vector length information

* for-next/kcsan:
  : Enable KCSAN for arm64
  arm64: Enable KCSAN
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* arm64/for-next/perf: (32 commits)
  arm64: perf: Don't register user access sysctl handler multiple times
  drivers: perf: marvell_cn10k: fix an IS_ERR() vs NULL check
  perf/smmuv3: Fix unused variable warning when CONFIG_OF=n
  arm64: perf: Support new DT compatibles
  arm64: perf: Simplify registration boilerplate
  arm64: perf: Support Denver and Carmel PMUs
  drivers/perf: hisi: Add driver for HiSilicon PCIe PMU
  docs: perf: Add description for HiSilicon PCIe PMU driver
  dt-bindings: perf: Add YAML schemas for Marvell CN10K LLC-TAD pmu bindings
  drivers: perf: Add LLC-TAD perf counter support
  perf/smmuv3: Synthesize IIDR from CoreSight ID registers
  perf/smmuv3: Add devicetree support
  dt-bindings: Add Arm SMMUv3 PMCG binding
  perf/arm-cmn: Add debugfs topology info
  perf/arm-cmn: Add CI-700 Support
  dt-bindings: perf: arm-cmn: Add CI-700
  perf/arm-cmn: Support new IP features
  perf/arm-cmn: Demarcate CMN-600 specifics
  perf/arm-cmn: Move group validation data off-stack
  perf/arm-cmn: Optimise DTC counter accesses
  ...

* for-next/misc:
  : Miscellaneous patches
  arm64: Use correct method to calculate nomap region boundaries
  arm64: Drop outdated links in comments
  arm64: errata: Fix exec handling in erratum 1418040 workaround
  arm64: Unhash early pointer print plus improve comment
  asm-generic: introduce io_stop_wc() and add implementation for ARM64
  arm64: remove __dma_*_area() aliases
  docs/arm64: delete a space from tagged-address-abi
  arm64/fp: Add comments documenting the usage of state restore functions
  arm64: mm: Use asid feature macro for cheanup
  arm64: mm: Rename asid2idx() to ctxid2asid()
  arm64: kexec: reduce calls to page_address()
  arm64: extable: remove unused ex_handler_t definition
  arm64: entry: Use SDEI event constants
  arm64: Simplify checking for populated DT
  arm64/kvm: Fix bitrotted comment for SVE handling in handle_exit.c

* for-next/cache-ops-dzp:
  : Avoid DC instructions when DCZID_EL0.DZP == 1
  arm64: mte: DC {GVA,GZVA} shouldn't be used when DCZID_EL0.DZP == 1
  arm64: clear_page() shouldn't use DC ZVA when DCZID_EL0.DZP == 1

* for-next/stacktrace:
  : Unify the arm64 unwind code
  arm64: Make some stacktrace functions private
  arm64: Make dump_backtrace() use arch_stack_walk()
  arm64: Make profile_pc() use arch_stack_walk()
  arm64: Make return_address() use arch_stack_walk()
  arm64: Make __get_wchan() use arch_stack_walk()
  arm64: Make perf_callchain_kernel() use arch_stack_walk()
  arm64: Mark __switch_to() as __sched
  arm64: Add comment for stack_info::kr_cur
  arch: Make ARCH_STACKWALK independent of STACKTRACE

* for-next/xor-neon:
  : Use SHA3 instructions to speed up XOR
  arm64/xor: use EOR3 instructions when available

* for-next/kasan:
  : Log potential KASAN shadow aliases
  arm64: mm: log potential KASAN shadow alias
  arm64: mm: use die_kernel_fault() in do_mem_abort()

* for-next/armv8_7-fp:
  : Add HWCAPS for ARMv8.7 FEAT_AFP amd FEAT_RPRES
  arm64: cpufeature: add HWCAP for FEAT_RPRES
  arm64: add ID_AA64ISAR2_EL1 sys register
  arm64: cpufeature: add HWCAP for FEAT_AFP

* for-next/atomics:
  : arm64 atomics clean-ups and codegen improvements
  arm64: atomics: lse: define RETURN ops in terms of FETCH ops
  arm64: atomics: lse: improve constraints for simple ops
  arm64: atomics: lse: define ANDs in terms of ANDNOTs
  arm64: atomics lse: define SUBs in terms of ADDs
  arm64: atomics: format whitespace consistently

* for-next/bti:
  : BTI clean-ups
  arm64: Ensure that the 'bti' macro is defined where linkage.h is included
  arm64: Use BTI C directly and unconditionally
  arm64: Unconditionally override SYM_FUNC macros
  arm64: Add macro version of the BTI instruction
  arm64: ftrace: add missing BTIs
  arm64: kexec: use __pa_symbol(empty_zero_page)
  arm64: update PAC description for kernel

* for-next/sve:
  : SVE code clean-ups and refactoring in prepararation of Scalable Matrix Extensions
  arm64/sve: Minor clarification of ABI documentation
  arm64/sve: Generalise vector length configuration prctl() for SME
  arm64/sve: Make sysctl interface for SVE reusable by SME

* for-next/kselftest:
  : arm64 kselftest additions
  kselftest/arm64: Add pidbench for floating point syscall cases
  kselftest/arm64: Add a test program to exercise the syscall ABI
  kselftest/arm64: Allow signal tests to trigger from a function
  kselftest/arm64: Parameterise ptrace vector length information

* for-next/kcsan:
  : Enable KCSAN for arm64
  arm64: Enable KCSAN
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: Use BTI C directly and unconditionally</title>
<updated>2021-12-14T18:12:58+00:00</updated>
<author>
<name>Mark Brown</name>
<email>broonie@kernel.org</email>
</author>
<published>2021-12-14T15:27:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=742a15b1a23aa43bde2d9d681281ec1925be13fd'/>
<id>742a15b1a23aa43bde2d9d681281ec1925be13fd</id>
<content type='text'>
Now we have a macro for BTI C that looks like a regular instruction change
all the users of the current BTI_C macro to just emit a BTI C directly and
remove the macro.

This does mean that we now unconditionally BTI annotate all assembly
functions, meaning that they are worse in this respect than code generated
by the compiler. The overhead should be minimal for implementations with a
reasonable HINT implementation.

Signed-off-by: Mark Brown &lt;broonie@kernel.org&gt;
Reviewed-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Acked-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Link: https://lore.kernel.org/r/20211214152714.2380849-4-broonie@kernel.org
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Now we have a macro for BTI C that looks like a regular instruction change
all the users of the current BTI_C macro to just emit a BTI C directly and
remove the macro.

This does mean that we now unconditionally BTI annotate all assembly
functions, meaning that they are worse in this respect than code generated
by the compiler. The overhead should be minimal for implementations with a
reasonable HINT implementation.

Signed-off-by: Mark Brown &lt;broonie@kernel.org&gt;
Reviewed-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Acked-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Link: https://lore.kernel.org/r/20211214152714.2380849-4-broonie@kernel.org
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64/xor: use EOR3 instructions when available</title>
<updated>2021-12-14T12:14:26+00:00</updated>
<author>
<name>Ard Biesheuvel</name>
<email>ardb@kernel.org</email>
</author>
<published>2021-12-13T14:02:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=2c54b423cf85baed5ad9f9546f6c8ea741774a06'/>
<id>2c54b423cf85baed5ad9f9546f6c8ea741774a06</id>
<content type='text'>
Use the EOR3 instruction to implement xor_blocks() if the instruction is
available, which is the case if the CPU implements the SHA-3 extension.
This is about 20% faster on Apple M1 when using the 5-way version.

Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Link: https://lore.kernel.org/r/20211213140252.2856053-1-ardb@kernel.org
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Use the EOR3 instruction to implement xor_blocks() if the instruction is
available, which is the case if the CPU implements the SHA-3 extension.
This is about 20% faster on Apple M1 when using the 5-way version.

Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Link: https://lore.kernel.org/r/20211213140252.2856053-1-ardb@kernel.org
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: mte: DC {GVA,GZVA} shouldn't be used when DCZID_EL0.DZP == 1</title>
<updated>2021-12-06T17:02:10+00:00</updated>
<author>
<name>Reiji Watanabe</name>
<email>reijiw@google.com</email>
</author>
<published>2021-12-06T00:47:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=685e2564daa1493053fcd7f1dbed38b35ee2f3cb'/>
<id>685e2564daa1493053fcd7f1dbed38b35ee2f3cb</id>
<content type='text'>
Currently, mte_set_mem_tag_range() and mte_zero_clear_page_tags() use
DC {GVA,GZVA} unconditionally.  But, they should make sure that
DCZID_EL0.DZP, which indicates whether or not use of those instructions
is prohibited, is zero when using those instructions.
Use ST{G,ZG,Z2G} instead when DCZID_EL0.DZP == 1.

Fixes: 013bb59dbb7c ("arm64: mte: handle tags zeroing at page allocation time")
Fixes: 3d0cca0b02ac ("kasan: speed up mte_set_mem_tag_range")
Signed-off-by: Reiji Watanabe &lt;reijiw@google.com&gt;
Link: https://lore.kernel.org/r/20211206004736.1520989-3-reijiw@google.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently, mte_set_mem_tag_range() and mte_zero_clear_page_tags() use
DC {GVA,GZVA} unconditionally.  But, they should make sure that
DCZID_EL0.DZP, which indicates whether or not use of those instructions
is prohibited, is zero when using those instructions.
Use ST{G,ZG,Z2G} instead when DCZID_EL0.DZP == 1.

Fixes: 013bb59dbb7c ("arm64: mte: handle tags zeroing at page allocation time")
Fixes: 3d0cca0b02ac ("kasan: speed up mte_set_mem_tag_range")
Signed-off-by: Reiji Watanabe &lt;reijiw@google.com&gt;
Link: https://lore.kernel.org/r/20211206004736.1520989-3-reijiw@google.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: clear_page() shouldn't use DC ZVA when DCZID_EL0.DZP == 1</title>
<updated>2021-12-06T17:02:10+00:00</updated>
<author>
<name>Reiji Watanabe</name>
<email>reijiw@google.com</email>
</author>
<published>2021-12-06T00:47:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f0616abd4e67143b45b04b565839148458857347'/>
<id>f0616abd4e67143b45b04b565839148458857347</id>
<content type='text'>
Currently, clear_page() uses DC ZVA instruction unconditionally.  But it
should make sure that DCZID_EL0.DZP, which indicates whether or not use
of DC ZVA instruction is prohibited, is zero when using the instruction.
Use STNP instead when DCZID_EL0.DZP == 1.

Fixes: f27bb139c387 ("arm64: Miscellaneous library functions")
Signed-off-by: Reiji Watanabe &lt;reijiw@google.com&gt;
Reviewed-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Link: https://lore.kernel.org/r/20211206004736.1520989-2-reijiw@google.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently, clear_page() uses DC ZVA instruction unconditionally.  But it
should make sure that DCZID_EL0.DZP, which indicates whether or not use
of DC ZVA instruction is prohibited, is zero when using the instruction.
Use STNP instead when DCZID_EL0.DZP == 1.

Fixes: f27bb139c387 ("arm64: Miscellaneous library functions")
Signed-off-by: Reiji Watanabe &lt;reijiw@google.com&gt;
Reviewed-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Link: https://lore.kernel.org/r/20211206004736.1520989-2-reijiw@google.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'kbuild-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild</title>
<updated>2021-11-08T17:15:45+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-11-08T17:15:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=1e9ed9360f80d13e41684ca458f01fdf922c7c57'/>
<id>1e9ed9360f80d13e41684ca458f01fdf922c7c57</id>
<content type='text'>
Pull Kbuild updates from Masahiro Yamada:

 - Remove the global -isystem compiler flag, which was made possible by
   the introduction of &lt;linux/stdarg.h&gt;

 - Improve the Kconfig help to print the location in the top menu level

 - Fix "FORCE prerequisite is missing" build warning for sparc

 - Add new build targets, tarzst-pkg and perf-tarzst-src-pkg, which
   generate a zstd-compressed tarball

 - Prevent gen_init_cpio tool from generating a corrupted cpio when
   KBUILD_BUILD_TIMESTAMP is set to 2106-02-07 or later

 - Misc cleanups

* tag 'kbuild-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (28 commits)
  kbuild: use more subdir- for visiting subdirectories while cleaning
  sh: remove meaningless archclean line
  initramfs: Check timestamp to prevent broken cpio archive
  kbuild: split DEBUG_CFLAGS out to scripts/Makefile.debug
  gen_init_cpio: add static const qualifiers
  kbuild: Add make tarzst-pkg build option
  scripts: update the comments of kallsyms support
  sparc: Add missing "FORCE" target when using if_changed
  kconfig: refactor conf_touch_dep()
  kconfig: refactor conf_write_dep()
  kconfig: refactor conf_write_autoconf()
  kconfig: add conf_get_autoheader_name()
  kconfig: move sym_escape_string_value() to confdata.c
  kconfig: refactor listnewconfig code
  kconfig: refactor conf_write_symbol()
  kconfig: refactor conf_write_heading()
  kconfig: remove 'const' from the return type of sym_escape_string_value()
  kconfig: rename a variable in the lexer to a clearer name
  kconfig: narrow the scope of variables in the lexer
  kconfig: Create links to main menu items in search
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull Kbuild updates from Masahiro Yamada:

 - Remove the global -isystem compiler flag, which was made possible by
   the introduction of &lt;linux/stdarg.h&gt;

 - Improve the Kconfig help to print the location in the top menu level

 - Fix "FORCE prerequisite is missing" build warning for sparc

 - Add new build targets, tarzst-pkg and perf-tarzst-src-pkg, which
   generate a zstd-compressed tarball

 - Prevent gen_init_cpio tool from generating a corrupted cpio when
   KBUILD_BUILD_TIMESTAMP is set to 2106-02-07 or later

 - Misc cleanups

* tag 'kbuild-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (28 commits)
  kbuild: use more subdir- for visiting subdirectories while cleaning
  sh: remove meaningless archclean line
  initramfs: Check timestamp to prevent broken cpio archive
  kbuild: split DEBUG_CFLAGS out to scripts/Makefile.debug
  gen_init_cpio: add static const qualifiers
  kbuild: Add make tarzst-pkg build option
  scripts: update the comments of kallsyms support
  sparc: Add missing "FORCE" target when using if_changed
  kconfig: refactor conf_touch_dep()
  kconfig: refactor conf_write_dep()
  kconfig: refactor conf_write_autoconf()
  kconfig: add conf_get_autoheader_name()
  kconfig: move sym_escape_string_value() to confdata.c
  kconfig: refactor listnewconfig code
  kconfig: refactor conf_write_symbol()
  kconfig: refactor conf_write_heading()
  kconfig: remove 'const' from the return type of sym_escape_string_value()
  kconfig: rename a variable in the lexer to a clearer name
  kconfig: narrow the scope of variables in the lexer
  kconfig: Create links to main menu items in search
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: extable: consolidate definitions</title>
<updated>2021-10-21T09:45:22+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2021-10-19T16:02:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=819771cc289226e392d5d45f1d162b47ace4eff6'/>
<id>819771cc289226e392d5d45f1d162b47ace4eff6</id>
<content type='text'>
In subsequent patches we'll alter the structure and usage of struct
exception_table_entry. For inline assembly, we create these using the
`_ASM_EXTABLE()` CPP macro defined in &lt;asm/uaccess.h&gt;, and for plain
assembly code we use the `_asm_extable()` GAS macro defined in
&lt;asm/assembler.h&gt;, which are largely identical save for different
escaping and stringification requirements.

This patch moves the common definitions to a new &lt;asm/asm-extable.h&gt;
header, so that it's easier to keep the two in-sync, and to remove the
implication that these are only used for uaccess helpers (as e.g.
load_unaligned_zeropad() is only used on kernel memory, and depends upon
`_ASM_EXTABLE()`.

At the same time, a few minor modifications are made for clarity and in
preparation for subsequent patches:

* The structure creation is factored out into an `__ASM_EXTABLE_RAW()`
  macro. This will make it easier to support different fixup variants in
  subsequent patches without needing to update all users of
  `_ASM_EXTABLE()`, and makes it easier to see tha the CPP and GAS
  variants of the macros are structurally identical.

  For the CPP macro, the stringification of fields is left to the
  wrapper macro, `_ASM_EXTABLE()`, as in subsequent patches it will be
  necessary to stringify fields in wrapper macros to safely concatenate
  strings which cannot be token-pasted together in CPP.

* The fields of the structure are created separately on their own lines.
  This will make it easier to add/remove/modify individual fields
  clearly.

* Additional parentheses are added around the use of macro arguments in
  field definitions to avoid any potential problems with evaluation due
  to operator precedence, and to make errors upon misuse clearer.

* USER() is moved into &lt;asm/asm-uaccess.h&gt;, as it is not required by all
  assembly code, and is already refered to by comments in that file.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Reviewed-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Robin Murphy &lt;robin.murphy@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20211019160219.5202-8-mark.rutland@arm.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In subsequent patches we'll alter the structure and usage of struct
exception_table_entry. For inline assembly, we create these using the
`_ASM_EXTABLE()` CPP macro defined in &lt;asm/uaccess.h&gt;, and for plain
assembly code we use the `_asm_extable()` GAS macro defined in
&lt;asm/assembler.h&gt;, which are largely identical save for different
escaping and stringification requirements.

This patch moves the common definitions to a new &lt;asm/asm-extable.h&gt;
header, so that it's easier to keep the two in-sync, and to remove the
implication that these are only used for uaccess helpers (as e.g.
load_unaligned_zeropad() is only used on kernel memory, and depends upon
`_ASM_EXTABLE()`.

At the same time, a few minor modifications are made for clarity and in
preparation for subsequent patches:

* The structure creation is factored out into an `__ASM_EXTABLE_RAW()`
  macro. This will make it easier to support different fixup variants in
  subsequent patches without needing to update all users of
  `_ASM_EXTABLE()`, and makes it easier to see tha the CPP and GAS
  variants of the macros are structurally identical.

  For the CPP macro, the stringification of fields is left to the
  wrapper macro, `_ASM_EXTABLE()`, as in subsequent patches it will be
  necessary to stringify fields in wrapper macros to safely concatenate
  strings which cannot be token-pasted together in CPP.

* The fields of the structure are created separately on their own lines.
  This will make it easier to add/remove/modify individual fields
  clearly.

* Additional parentheses are added around the use of macro arguments in
  field definitions to avoid any potential problems with evaluation due
  to operator precedence, and to make errors upon misuse clearer.

* USER() is moved into &lt;asm/asm-uaccess.h&gt;, as it is not required by all
  assembly code, and is already refered to by comments in that file.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Reviewed-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Robin Murphy &lt;robin.murphy@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20211019160219.5202-8-mark.rutland@arm.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: lib: __arch_copy_to_user(): fold fixups into body</title>
<updated>2021-10-21T09:45:21+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2021-10-19T16:02:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=139f9ab73d60cf76d770841a019c5284fcf26c74'/>
<id>139f9ab73d60cf76d770841a019c5284fcf26c74</id>
<content type='text'>
Like other functions, __arch_copy_to_user() places its exception fixups
in the `.fixup` section without any clear association with
__arch_copy_to_user() itself. If we backtrace the fixup code, it will be
symbolized as an offset from the nearest prior symbol, which happens to
be `__entry_tramp_text_end`. Further, since the PC adjustment for the
fixup is akin to a direct branch rather than a function call,
__arch_copy_to_user() itself will be missing from the backtrace.

This is confusing and hinders debugging. In general this pattern will
also be problematic for CONFIG_LIVEPATCH, since fixups often return to
their associated function, but this isn't accurately captured in the
stacktrace.

To solve these issues for assembly functions, we must move fixups into
the body of the functions themselves, after the usual fast-path returns.
This patch does so for __arch_copy_to_user().

Inline assembly will be dealt with in subsequent patches.

Other than the improved backtracing, there should be no functional
change as a result of this patch.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Acked-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Reviewed-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Mark Brown &lt;broonie@kernel.org&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20211019160219.5202-4-mark.rutland@arm.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Like other functions, __arch_copy_to_user() places its exception fixups
in the `.fixup` section without any clear association with
__arch_copy_to_user() itself. If we backtrace the fixup code, it will be
symbolized as an offset from the nearest prior symbol, which happens to
be `__entry_tramp_text_end`. Further, since the PC adjustment for the
fixup is akin to a direct branch rather than a function call,
__arch_copy_to_user() itself will be missing from the backtrace.

This is confusing and hinders debugging. In general this pattern will
also be problematic for CONFIG_LIVEPATCH, since fixups often return to
their associated function, but this isn't accurately captured in the
stacktrace.

To solve these issues for assembly functions, we must move fixups into
the body of the functions themselves, after the usual fast-path returns.
This patch does so for __arch_copy_to_user().

Inline assembly will be dealt with in subsequent patches.

Other than the improved backtracing, there should be no functional
change as a result of this patch.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Acked-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Reviewed-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Mark Brown &lt;broonie@kernel.org&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20211019160219.5202-4-mark.rutland@arm.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: lib: __arch_copy_from_user(): fold fixups into body</title>
<updated>2021-10-21T09:45:21+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2021-10-19T16:02:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=4012e0e22739eef92499171957145a60445c0b60'/>
<id>4012e0e22739eef92499171957145a60445c0b60</id>
<content type='text'>
Like other functions, __arch_copy_from_user() places its exception
fixups in the `.fixup` section without any clear association with
__arch_copy_from_user() itself. If we backtrace the fixup code, it will
be symbolized as an offset from the nearest prior symbol, which happens
to be `__entry_tramp_text_end`. Further, since the PC adjustment for the
fixup is akin to a direct branch rather than a function call,
__arch_copy_from_user() itself will be missing from the backtrace.

This is confusing and hinders debugging. In general this pattern will
also be problematic for CONFIG_LIVEPATCH, since fixups often return to
their associated function, but this isn't accurately captured in the
stacktrace.

To solve these issues for assembly functions, we must move fixups into
the body of the functions themselves, after the usual fast-path returns.
This patch does so for __arch_copy_from_user().

Inline assembly will be dealt with in subsequent patches.

Other than the improved backtracing, there should be no functional
change as a result of this patch.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Acked-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Reviewed-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Mark Brown &lt;broonie@kernel.org&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20211019160219.5202-3-mark.rutland@arm.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Like other functions, __arch_copy_from_user() places its exception
fixups in the `.fixup` section without any clear association with
__arch_copy_from_user() itself. If we backtrace the fixup code, it will
be symbolized as an offset from the nearest prior symbol, which happens
to be `__entry_tramp_text_end`. Further, since the PC adjustment for the
fixup is akin to a direct branch rather than a function call,
__arch_copy_from_user() itself will be missing from the backtrace.

This is confusing and hinders debugging. In general this pattern will
also be problematic for CONFIG_LIVEPATCH, since fixups often return to
their associated function, but this isn't accurately captured in the
stacktrace.

To solve these issues for assembly functions, we must move fixups into
the body of the functions themselves, after the usual fast-path returns.
This patch does so for __arch_copy_from_user().

Inline assembly will be dealt with in subsequent patches.

Other than the improved backtracing, there should be no functional
change as a result of this patch.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Acked-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Reviewed-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Mark Brown &lt;broonie@kernel.org&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20211019160219.5202-3-mark.rutland@arm.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: lib: __arch_clear_user(): fold fixups into body</title>
<updated>2021-10-21T09:45:21+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2021-10-19T16:02:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=35d67794b88283337e0d311a4dbacc42d07a12a5'/>
<id>35d67794b88283337e0d311a4dbacc42d07a12a5</id>
<content type='text'>
Like other functions, __arch_clear_user() places its exception fixups in
the `.fixup` section without any clear association with
__arch_clear_user() itself. If we backtrace the fixup code, it will be
symbolized as an offset from the nearest prior symbol, which happens to
be `__entry_tramp_text_end`. Further, since the PC adjustment for the
fixup is akin to a direct branch rather than a function call,
__arch_clear_user() itself will be missing from the backtrace.

This is confusing and hinders debugging. In general this pattern will
also be problematic for CONFIG_LIVEPATCH, since fixups often return to
their associated function, but this isn't accurately captured in the
stacktrace.

To solve these issues for assembly functions, we must move fixups into
the body of the functions themselves, after the usual fast-path returns.
This patch does so for __arch_clear_user().

Inline assembly will be dealt with in subsequent patches.

Other than the improved backtracing, there should be no functional
change as a result of this patch.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Acked-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Reviewed-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Mark Brown &lt;broonie@kernel.org&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20211019160219.5202-2-mark.rutland@arm.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Like other functions, __arch_clear_user() places its exception fixups in
the `.fixup` section without any clear association with
__arch_clear_user() itself. If we backtrace the fixup code, it will be
symbolized as an offset from the nearest prior symbol, which happens to
be `__entry_tramp_text_end`. Further, since the PC adjustment for the
fixup is akin to a direct branch rather than a function call,
__arch_clear_user() itself will be missing from the backtrace.

This is confusing and hinders debugging. In general this pattern will
also be problematic for CONFIG_LIVEPATCH, since fixups often return to
their associated function, but this isn't accurately captured in the
stacktrace.

To solve these issues for assembly functions, we must move fixups into
the body of the functions themselves, after the usual fast-path returns.
This patch does so for __arch_clear_user().

Inline assembly will be dealt with in subsequent patches.

Other than the improved backtracing, there should be no functional
change as a result of this patch.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Acked-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Reviewed-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Cc: Mark Brown &lt;broonie@kernel.org&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20211019160219.5202-2-mark.rutland@arm.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
