<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git/arch/arm64/Kconfig, branch v6.3</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v6.3</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v6.3'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2023-03-02T22:57:53+00:00</updated>
<entry>
<title>Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux</title>
<updated>2023-03-02T22:57:53+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-03-02T22:57:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=39ce4395c3ba730341b067e1fb8abbdf9c47ca77'/>
<id>urn:sha1:39ce4395c3ba730341b067e1fb8abbdf9c47ca77</id>
<content type='text'>
Pull arm64 fixes from Catalin Marinas:

 - In copy_highpage(), only reset the tag of the destination pointer if
   KASAN_HW_TAGS is enabled so that user-space MTE does not interfere
   with KASAN_SW_TAGS (which relies on top-byte-ignore).

 - Remove warning if SME is detected without SVE, the kernel can cope
   with such configuration (though none in the field currently).

 - In cfi_handler(), pass the ESR_EL1 value to die() for consistency
   with other die() callers.

 - Disable HUGETLB_PAGE_OPTIMIZE_VMEMMAP on arm64 since the pte
   manipulation from the generic vmemmap_remap_pte() does not follow the
   required ARM break-before-make sequence (clear the pte, flush the
   TLBs, set the new pte). It may be re-enabled once this sequence is
   sorted.

 - Fix possible memory leak in the arm64 ACPI code if the SMCCC version
   and conduit checks fail.

 - Forbid CALL_OPS with CC_OPTIMIZE_FOR_SIZE since gcc ignores
  -falign-functions=N with -Os.

 - Don't pretend KASLR is enabled if offset &lt; MIN_KIMG_ALIGN as no
   randomisation would actually take place.

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: kaslr: don't pretend KASLR is enabled if offset &lt; MIN_KIMG_ALIGN
  arm64: ftrace: forbid CALL_OPS with CC_OPTIMIZE_FOR_SIZE
  arm64: acpi: Fix possible memory leak of ffh_ctxt
  arm64: mm: hugetlb: Disable HUGETLB_PAGE_OPTIMIZE_VMEMMAP
  arm64: pass ESR_ELx to die() of cfi_handler
  arm64/fpsimd: Remove warning for SME without SVE
  arm64: Reset KASAN tag in copy_highpage with HW tags only
</content>
</entry>
<entry>
<title>arm64: ftrace: forbid CALL_OPS with CC_OPTIMIZE_FOR_SIZE</title>
<updated>2023-02-28T10:04:53+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2023-02-27T11:58:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=b3f11af9b2ce14d4662753d097a21e1d37a06fda'/>
<id>urn:sha1:b3f11af9b2ce14d4662753d097a21e1d37a06fda</id>
<content type='text'>
Florian reports that when building with CONFIG_CC_OPTIMIZE_FOR_SIZE=y,
he sees "Misaligned patch-site" warnings at boot, e.g.

| Misaligned patch-site bcm2836_arm_irqchip_handle_irq+0x0/0x88
| WARNING: CPU: 0 PID: 0 at arch/arm64/kernel/ftrace.c:120 ftrace_call_adjust+0x4c/0x70

This is because GCC will silently ignore `-falign-functions=N` when
passed `-Os`, resulting in functions not being aligned as we expect.
This is a known issue, and to account for this we modified the kernel to
avoid `-Os` generally. Unfortunately we forgot to account for
CONFIG_CC_OPTIMIZE_FOR_SIZE.

Forbid the use of CALL_OPS with CONFIG_CC_OPTIMIZE_FOR_SIZE=y to prevent
this issue. All exising ftrace features will work as before, though
without the performance benefit of CALL_OPS.

Reported-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Link: http://lore.kernel.org/linux-arm-kernel/2d9284c3-3805-402b-5423-520ced56d047@gmail.com
Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Marc Zyngier &lt;maz@kernel.org&gt;
Cc: Stefan Wahren &lt;stefan.wahren@i2se.com&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Tested-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Link: https://lore.kernel.org/r/20230227115819.365630-1-mark.rutland@arm.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
</entry>
<entry>
<title>arm64: mm: hugetlb: Disable HUGETLB_PAGE_OPTIMIZE_VMEMMAP</title>
<updated>2023-02-24T13:43:10+00:00</updated>
<author>
<name>Catalin Marinas</name>
<email>catalin.marinas@arm.com</email>
</author>
<published>2023-02-22T17:52:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=060a2c92d1b627c86c5c42ca69baf00457c00c5a'/>
<id>urn:sha1:060a2c92d1b627c86c5c42ca69baf00457c00c5a</id>
<content type='text'>
Revert the HUGETLB_PAGE_FREE_VMEMMAP selection from commit 1e63ac088f20
("arm64: mm: hugetlb: enable HUGETLB_PAGE_FREE_VMEMMAP for arm64") but
keep the flush_dcache_page() compound_head() change as it aligns with
the corresponding check in the __sync_icache_dcache() function.

The original config option was renamed in commit 47010c040dec ("mm:
hugetlb_vmemmap: cleanup CONFIG_HUGETLB_PAGE_FREE_VMEMMAP*") to
HUGETLB_PAGE_OPTIMIZE_VMEMMAP and the flush_dcache_page() check was
further simplified by commit 2da1c30929a2 ("mm: hugetlb_vmemmap: delete
hugetlb_optimize_vmemmap_enabled()").

The reason for the revert is that the generic vmemmap_remap_pte()
function changes both the permissions (writeable to read-only) and the
output address (pfn) of the vmemmap ptes. This is deemed UNPREDICTABLE
by the Arm architecture without a break-before-make sequence (make the
PTE invalid, TLBI, write the new valid PTE). However, such sequence is
not possible since the vmemmap may be concurrently accessed by the
kernel. Disable the optimisation until a better solution is found.

Fixes: 1e63ac088f20 ("arm64: mm: hugetlb: enable HUGETLB_PAGE_FREE_VMEMMAP for arm64")
Cc: &lt;stable@vger.kernel.org&gt; # 5.19.x
Cc: Muchun Song &lt;muchun.song@linux.dev&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: Anshuman Khandual &lt;anshuman.khandual@arm.com&gt;
Link: https://lore.kernel.org/r/Y9pZALdn3pKiJUeQ@arm.com
Reviewed-by: Anshuman Khandual &lt;anshuman.khandual@arm.com&gt;
Link: https://lore.kernel.org/r/20230222175232.540851-1-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
</entry>
<entry>
<title>Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux</title>
<updated>2023-02-21T23:27:48+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-02-21T23:27:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=8bf1a529cd664c8e5268381f1e24fe67aa611dd3'/>
<id>urn:sha1:8bf1a529cd664c8e5268381f1e24fe67aa611dd3</id>
<content type='text'>
Pull arm64 updates from Catalin Marinas:

 - Support for arm64 SME 2 and 2.1. SME2 introduces a new 512-bit
   architectural register (ZT0, for the look-up table feature) that
   Linux needs to save/restore

 - Include TPIDR2 in the signal context and add the corresponding
   kselftests

 - Perf updates: Arm SPEv1.2 support, HiSilicon uncore PMU updates, ACPI
   support to the Marvell DDR and TAD PMU drivers, reset DTM_PMU_CONFIG
   (ARM CMN) at probe time

 - Support for DYNAMIC_FTRACE_WITH_CALL_OPS on arm64

 - Permit EFI boot with MMU and caches on. Instead of cleaning the
   entire loaded kernel image to the PoC and disabling the MMU and
   caches before branching to the kernel bare metal entry point, leave
   the MMU and caches enabled and rely on EFI's cacheable 1:1 mapping of
   all of system RAM to populate the initial page tables

 - Expose the AArch32 (compat) ELF_HWCAP features to user in an arm64
   kernel (the arm32 kernel only defines the values)

 - Harden the arm64 shadow call stack pointer handling: stash the shadow
   stack pointer in the task struct on interrupt, load it directly from
   this structure

 - Signal handling cleanups to remove redundant validation of size
   information and avoid reading the same data from userspace twice

 - Refactor the hwcap macros to make use of the automatically generated
   ID registers. It should make new hwcaps writing less error prone

 - Further arm64 sysreg conversion and some fixes

 - arm64 kselftest fixes and improvements

 - Pointer authentication cleanups: don't sign leaf functions, unify
   asm-arch manipulation

 - Pseudo-NMI code generation optimisations

 - Minor fixes for SME and TPIDR2 handling

 - Miscellaneous updates: ARCH_FORCE_MAX_ORDER is now selectable,
   replace strtobool() to kstrtobool() in the cpufeature.c code, apply
   dynamic shadow call stack in two passes, intercept pfn changes in
   set_pte_at() without the required break-before-make sequence, attempt
   to dump all instructions on unhandled kernel faults

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (130 commits)
  arm64: fix .idmap.text assertion for large kernels
  kselftest/arm64: Don't require FA64 for streaming SVE+ZA tests
  kselftest/arm64: Copy whole EXTRA context
  arm64: kprobes: Drop ID map text from kprobes blacklist
  perf: arm_spe: Print the version of SPE detected
  perf: arm_spe: Add support for SPEv1.2 inverted event filtering
  perf: Add perf_event_attr::config3
  arm64/sme: Fix __finalise_el2 SMEver check
  drivers/perf: fsl_imx8_ddr_perf: Remove set-but-not-used variable
  arm64/signal: Only read new data when parsing the ZT context
  arm64/signal: Only read new data when parsing the ZA context
  arm64/signal: Only read new data when parsing the SVE context
  arm64/signal: Avoid rereading context frame sizes
  arm64/signal: Make interface for restore_fpsimd_context() consistent
  arm64/signal: Remove redundant size validation from parse_user_sigframe()
  arm64/signal: Don't redundantly verify FPSIMD magic
  arm64/cpufeature: Use helper macros to specify hwcaps
  arm64/cpufeature: Always use symbolic name for feature value in hwcaps
  arm64/sysreg: Initial unsigned annotations for ID registers
  arm64/sysreg: Initial annotation of signed ID registers
  ...
</content>
</entry>
<entry>
<title>Merge branches 'for-next/sysreg', 'for-next/sme', 'for-next/kselftest', 'for-next/misc', 'for-next/sme2', 'for-next/tpidr2', 'for-next/scs', 'for-next/compat-hwcap', 'for-next/ftrace', 'for-next/efi-boot-mmu-on', 'for-next/ptrauth' and 'for-next/pseudo-nmi', remote-tracking branch 'arm64/for-next/perf' into for-next/core</title>
<updated>2023-02-10T18:51:49+00:00</updated>
<author>
<name>Catalin Marinas</name>
<email>catalin.marinas@arm.com</email>
</author>
<published>2023-02-10T18:51:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=156010ed9c2ac1e9df6c11b1f688cf8a6e0152e6'/>
<id>urn:sha1:156010ed9c2ac1e9df6c11b1f688cf8a6e0152e6</id>
<content type='text'>
* arm64/for-next/perf:
  perf: arm_spe: Print the version of SPE detected
  perf: arm_spe: Add support for SPEv1.2 inverted event filtering
  perf: Add perf_event_attr::config3
  drivers/perf: fsl_imx8_ddr_perf: Remove set-but-not-used variable
  perf: arm_spe: Support new SPEv1.2/v8.7 'not taken' event
  perf: arm_spe: Use new PMSIDR_EL1 register enums
  perf: arm_spe: Drop BIT() and use FIELD_GET/PREP accessors
  arm64/sysreg: Convert SPE registers to automatic generation
  arm64: Drop SYS_ from SPE register defines
  perf: arm_spe: Use feature numbering for PMSEVFR_EL1 defines
  perf/marvell: Add ACPI support to TAD uncore driver
  perf/marvell: Add ACPI support to DDR uncore driver
  perf/arm-cmn: Reset DTM_PMU_CONFIG at probe
  drivers/perf: hisi: Extract initialization of "cpa_pmu-&gt;pmu"
  drivers/perf: hisi: Simplify the parameters of hisi_pmu_init()
  drivers/perf: hisi: Advertise the PERF_PMU_CAP_NO_EXCLUDE capability

* for-next/sysreg:
  : arm64 sysreg and cpufeature fixes/updates
  KVM: arm64: Use symbolic definition for ISR_EL1.A
  arm64/sysreg: Add definition of ISR_EL1
  arm64/sysreg: Add definition for ICC_NMIAR1_EL1
  arm64/cpufeature: Remove 4 bit assumption in ARM64_FEATURE_MASK()
  arm64/sysreg: Fix errors in 32 bit enumeration values
  arm64/cpufeature: Fix field sign for DIT hwcap detection

* for-next/sme:
  : SME-related updates
  arm64/sme: Optimise SME exit on syscall entry
  arm64/sme: Don't use streaming mode to probe the maximum SME VL
  arm64/ptrace: Use system_supports_tpidr2() to check for TPIDR2 support

* for-next/kselftest: (23 commits)
  : arm64 kselftest fixes and improvements
  kselftest/arm64: Don't require FA64 for streaming SVE+ZA tests
  kselftest/arm64: Copy whole EXTRA context
  kselftest/arm64: Fix enumeration of systems without 128 bit SME for SSVE+ZA
  kselftest/arm64: Fix enumeration of systems without 128 bit SME
  kselftest/arm64: Don't require FA64 for streaming SVE tests
  kselftest/arm64: Limit the maximum VL we try to set via ptrace
  kselftest/arm64: Correct buffer size for SME ZA storage
  kselftest/arm64: Remove the local NUM_VL definition
  kselftest/arm64: Verify simultaneous SSVE and ZA context generation
  kselftest/arm64: Verify that SSVE signal context has SVE_SIG_FLAG_SM set
  kselftest/arm64: Remove spurious comment from MTE test Makefile
  kselftest/arm64: Support build of MTE tests with clang
  kselftest/arm64: Initialise current at build time in signal tests
  kselftest/arm64: Don't pass headers to the compiler as source
  kselftest/arm64: Remove redundant _start labels from FP tests
  kselftest/arm64: Fix .pushsection for strings in FP tests
  kselftest/arm64: Run BTI selftests on systems without BTI
  kselftest/arm64: Fix test numbering when skipping tests
  kselftest/arm64: Skip non-power of 2 SVE vector lengths in fp-stress
  kselftest/arm64: Only enumerate power of two VLs in syscall-abi
  ...

* for-next/misc:
  : Miscellaneous arm64 updates
  arm64/mm: Intercept pfn changes in set_pte_at()
  Documentation: arm64: correct spelling
  arm64: traps: attempt to dump all instructions
  arm64: Apply dynamic shadow call stack patching in two passes
  arm64: el2_setup.h: fix spelling typo in comments
  arm64: Kconfig: fix spelling
  arm64: cpufeature: Use kstrtobool() instead of strtobool()
  arm64: Avoid repeated AA64MMFR1_EL1 register read on pagefault path
  arm64: make ARCH_FORCE_MAX_ORDER selectable

* for-next/sme2: (23 commits)
  : Support for arm64 SME 2 and 2.1
  arm64/sme: Fix __finalise_el2 SMEver check
  kselftest/arm64: Remove redundant _start labels from zt-test
  kselftest/arm64: Add coverage of SME 2 and 2.1 hwcaps
  kselftest/arm64: Add coverage of the ZT ptrace regset
  kselftest/arm64: Add SME2 coverage to syscall-abi
  kselftest/arm64: Add test coverage for ZT register signal frames
  kselftest/arm64: Teach the generic signal context validation about ZT
  kselftest/arm64: Enumerate SME2 in the signal test utility code
  kselftest/arm64: Cover ZT in the FP stress test
  kselftest/arm64: Add a stress test program for ZT0
  arm64/sme: Add hwcaps for SME 2 and 2.1 features
  arm64/sme: Implement ZT0 ptrace support
  arm64/sme: Implement signal handling for ZT
  arm64/sme: Implement context switching for ZT0
  arm64/sme: Provide storage for ZT0
  arm64/sme: Add basic enumeration for SME2
  arm64/sme: Enable host kernel to access ZT0
  arm64/sme: Manually encode ZT0 load and store instructions
  arm64/esr: Document ISS for ZT0 being disabled
  arm64/sme: Document SME 2 and SME 2.1 ABI
  ...

* for-next/tpidr2:
  : Include TPIDR2 in the signal context
  kselftest/arm64: Add test case for TPIDR2 signal frame records
  kselftest/arm64: Add TPIDR2 to the set of known signal context records
  arm64/signal: Include TPIDR2 in the signal context
  arm64/sme: Document ABI for TPIDR2 signal information

* for-next/scs:
  : arm64: harden shadow call stack pointer handling
  arm64: Stash shadow stack pointer in the task struct on interrupt
  arm64: Always load shadow stack pointer directly from the task struct

* for-next/compat-hwcap:
  : arm64: Expose compat ARMv8 AArch32 features (HWCAPs)
  arm64: Add compat hwcap SSBS
  arm64: Add compat hwcap SB
  arm64: Add compat hwcap I8MM
  arm64: Add compat hwcap ASIMDBF16
  arm64: Add compat hwcap ASIMDFHM
  arm64: Add compat hwcap ASIMDDP
  arm64: Add compat hwcap FPHP and ASIMDHP

* for-next/ftrace:
  : Add arm64 support for DYNAMICE_FTRACE_WITH_CALL_OPS
  arm64: avoid executing padding bytes during kexec / hibernation
  arm64: Implement HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS
  arm64: ftrace: Update stale comment
  arm64: patching: Add aarch64_insn_write_literal_u64()
  arm64: insn: Add helpers for BTI
  arm64: Extend support for CONFIG_FUNCTION_ALIGNMENT
  ACPI: Don't build ACPICA with '-Os'
  Compiler attributes: GCC cold function alignment workarounds
  ftrace: Add DYNAMIC_FTRACE_WITH_CALL_OPS

* for-next/efi-boot-mmu-on:
  : Permit arm64 EFI boot with MMU and caches on
  arm64: kprobes: Drop ID map text from kprobes blacklist
  arm64: head: Switch endianness before populating the ID map
  efi: arm64: enter with MMU and caches enabled
  arm64: head: Clean the ID map and the HYP text to the PoC if needed
  arm64: head: avoid cache invalidation when entering with the MMU on
  arm64: head: record the MMU state at primary entry
  arm64: kernel: move identity map out of .text mapping
  arm64: head: Move all finalise_el2 calls to after __enable_mmu

* for-next/ptrauth:
  : arm64 pointer authentication cleanup
  arm64: pauth: don't sign leaf functions
  arm64: unify asm-arch manipulation

* for-next/pseudo-nmi:
  : Pseudo-NMI code generation optimisations
  arm64: irqflags: use alternative branches for pseudo-NMI logic
  arm64: add ARM64_HAS_GIC_PRIO_RELAXED_SYNC cpucap
  arm64: make ARM64_HAS_GIC_PRIO_MASKING depend on ARM64_HAS_GIC_CPUIF_SYSREGS
  arm64: rename ARM64_HAS_IRQ_PRIO_MASKING to ARM64_HAS_GIC_PRIO_MASKING
  arm64: rename ARM64_HAS_SYSREG_GIC_CPUIF to ARM64_HAS_GIC_CPUIF_SYSREGS
</content>
</entry>
<entry>
<title>arm64: unify asm-arch manipulation</title>
<updated>2023-01-31T16:03:37+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2023-01-31T10:58:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=1e249c41ea43157fc69e1496e3b4feea999f107a'/>
<id>urn:sha1:1e249c41ea43157fc69e1496e3b4feea999f107a</id>
<content type='text'>
Assemblers will reject instructions not supported by a target
architecture version, and so we must explicitly tell the assembler the
latest architecture version for which we want to assemble instructions
from.

We've added a few AS_HAS_ARMV8_&lt;N&gt; definitions for this, in addition to
an inconsistently named AS_HAS_PAC definition, from which arm64's
top-level Makefile determines the architecture version that we intend to
target, and generates the `asm-arch` variable.

To make this a bit clearer and easier to maintain, this patch reworks
the Makefile to determine asm-arch in a single if-else-endif chain.
AS_HAS_PAC, which is defined when the assembler supports
`-march=armv8.3-a`, is renamed to AS_HAS_ARMV8_3.

As the logic for armv8.3-a is lifted out of the block handling pointer
authentication, `asm-arch` may now be set to armv8.3-a regardless of
whether support for pointer authentication is selected. This means that
it will be possible to assemble armv8.3-a instructions even if we didn't
intend to, but this is consistent with our handling of other
architecture versions, and the compiler won't generate armv8.3-a
instructions regardless.

For the moment there's no need for an CONFIG_AS_HAS_ARMV8_1, as the code
for LSE atomics and LDAPR use individual `.arch_extension` entries and
do not require the baseline asm arch to be bumped to armv8.1-a. The
other armv8.1-a features (e.g. PAN) do not require assembler support.

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;
Reviewed-by: Mark Brown &lt;broonie@kernel.org&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20230131105809.991288-2-mark.rutland@arm.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
</entry>
<entry>
<title>arm64: Kconfig: fix spelling</title>
<updated>2023-01-26T17:44:35+00:00</updated>
<author>
<name>Randy Dunlap</name>
<email>rdunlap@infradead.org</email>
</author>
<published>2023-01-24T18:16:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=11fc944f7e14a67a2fbf578da5d7244525cf9571'/>
<id>urn:sha1:11fc944f7e14a67a2fbf578da5d7244525cf9571</id>
<content type='text'>
Fix spelling typos in arm64: (reported by codespell)
s/upto/up to/
s/familly/family/

Signed-off-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230124181605.14144-1-rdunlap@infradead.org
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
</entry>
<entry>
<title>arm64: Implement HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS</title>
<updated>2023-01-24T11:49:43+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2023-01-23T13:46:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=baaf553d3bc330697c68a00f96cf11f4edfeac7e'/>
<id>urn:sha1:baaf553d3bc330697c68a00f96cf11f4edfeac7e</id>
<content type='text'>
This patch enables support for DYNAMIC_FTRACE_WITH_CALL_OPS on arm64.
This allows each ftrace callsite to provide an ftrace_ops to the common
ftrace trampoline, allowing each callsite to invoke distinct tracer
functions without the need to fall back to list processing or to
allocate custom trampolines for each callsite. This significantly speeds
up cases where multiple distinct trace functions are used and callsites
are mostly traced by a single tracer.

The main idea is to place a pointer to the ftrace_ops as a literal at a
fixed offset from the function entry point, which can be recovered by
the common ftrace trampoline. Using a 64-bit literal avoids branch range
limitations, and permits the ops to be swapped atomically without
special considerations that apply to code-patching. In future this will
also allow for the implementation of DYNAMIC_FTRACE_WITH_DIRECT_CALLS
without branch range limitations by using additional fields in struct
ftrace_ops.

As noted in the core patch adding support for
DYNAMIC_FTRACE_WITH_CALL_OPS, this approach allows for directly invoking
ftrace_ops::func even for ftrace_ops which are dynamically-allocated (or
part of a module), without going via ftrace_ops_list_func.

Currently, this approach is not compatible with CLANG_CFI, as the
presence/absence of pre-function NOPs changes the offset of the
pre-function type hash, and there's no existing mechanism to ensure a
consistent offset for instrumented and uninstrumented functions. When
CLANG_CFI is enabled, the existing scheme with a global ops-&gt;func
pointer is used, and there should be no functional change. I am
currently working with others to allow the two to work together in
future (though this will liekly require updated compiler support).

I've benchamrked this with the ftrace_ops sample module [1], which is
not currently upstream, but available at:

  https://lore.kernel.org/lkml/20230103124912.2948963-1-mark.rutland@arm.com
  git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git ftrace-ops-sample-20230109

Using that module I measured the total time taken for 100,000 calls to a
trivial instrumented function, with a number of tracers enabled with
relevant filters (which would apply to the instrumented function) and a
number of tracers enabled with irrelevant filters (which would not apply
to the instrumented function). I tested on an M1 MacBook Pro, running
under a HVF-accelerated QEMU VM (i.e. on real hardware).

Before this patch:

  Number of tracers     || Total time  | Per-call average time (ns)
  Relevant | Irrelevant || (ns)        | Total        | Overhead
  =========+============++=============+==============+============
         0 |          0 ||      94,583 |         0.95 |           -
         0 |          1 ||      93,709 |         0.94 |           -
         0 |          2 ||      93,666 |         0.94 |           -
         0 |         10 ||      93,709 |         0.94 |           -
         0 |        100 ||      93,792 |         0.94 |           -
  ---------+------------++-------------+--------------+------------
         1 |          1 ||   6,467,833 |        64.68 |       63.73
         1 |          2 ||   7,509,708 |        75.10 |       74.15
         1 |         10 ||  23,786,792 |       237.87 |      236.92
         1 |        100 || 106,432,500 |     1,064.43 |     1063.38
  ---------+------------++-------------+--------------+------------
         1 |          0 ||   1,431,875 |        14.32 |       13.37
         2 |          0 ||   6,456,334 |        64.56 |       63.62
        10 |          0 ||  22,717,000 |       227.17 |      226.22
       100 |          0 || 103,293,667 |      1032.94 |     1031.99
  ---------+------------++-------------+--------------+--------------

  Note: per-call overhead is estimated relative to the baseline case
  with 0 relevant tracers and 0 irrelevant tracers.

After this patch

  Number of tracers     || Total time  | Per-call average time (ns)
  Relevant | Irrelevant || (ns)        | Total        | Overhead
  =========+============++=============+==============+============
         0 |          0 ||      94,541 |         0.95 |           -
         0 |          1 ||      93,666 |         0.94 |           -
         0 |          2 ||      93,709 |         0.94 |           -
         0 |         10 ||      93,667 |         0.94 |           -
         0 |        100 ||      93,792 |         0.94 |           -
  ---------+------------++-------------+--------------+------------
         1 |          1 ||     281,000 |         2.81 |        1.86
         1 |          2 ||     281,042 |         2.81 |        1.87
         1 |         10 ||     280,958 |         2.81 |        1.86
         1 |        100 ||     281,250 |         2.81 |        1.87
  ---------+------------++-------------+--------------+------------
         1 |          0 ||     280,959 |         2.81 |        1.86
         2 |          0 ||   6,502,708 |        65.03 |       64.08
        10 |          0 ||  18,681,209 |       186.81 |      185.87
       100 |          0 || 103,550,458 |     1,035.50 |     1034.56
  ---------+------------++-------------+--------------+------------

  Note: per-call overhead is estimated relative to the baseline case
  with 0 relevant tracers and 0 irrelevant tracers.

As can be seen from the above:

a) Whenever there is a single relevant tracer function associated with a
   tracee, the overhead of invoking the tracer is constant, and does not
   scale with the number of tracers which are *not* associated with that
   tracee.

b) The overhead for a single relevant tracer has dropped to ~1/7 of the
   overhead prior to this series (from 13.37ns to 1.86ns). This is
   largely due to permitting calls to dynamically-allocated ftrace_ops
   without going through ftrace_ops_list_func.

I've run the ftrace selftests from v6.2-rc3, which reports:

| # of passed:  110
| # of failed:  0
| # of unresolved:  3
| # of untested:  0
| # of unsupported:  0
| # of xfailed:  1
| # of undefined(test bug):  0

... where the unresolved entries were the tests for DIRECT functions
(which are not supported), and the checkbashisms selftest (which is
irrelevant here):

| [8] Test ftrace direct functions against tracers        [UNRESOLVED]
| [9] Test ftrace direct functions against kprobes        [UNRESOLVED]
| [62] Meta-selftest: Checkbashisms       [UNRESOLVED]

... with all other tests passing (or failing as expected).

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Florent Revest &lt;revest@chromium.org&gt;
Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20230123134603.1064407-9-mark.rutland@arm.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
</entry>
<entry>
<title>arm64: Extend support for CONFIG_FUNCTION_ALIGNMENT</title>
<updated>2023-01-24T11:49:43+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2023-01-23T13:45:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=47a15aa544279d34e14e17ca3b5855e39b946cec'/>
<id>urn:sha1:47a15aa544279d34e14e17ca3b5855e39b946cec</id>
<content type='text'>
On arm64 we don't align assembly function in the same way as C
functions. This somewhat limits the utility of
CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_64B for testing, and adds noise when
testing that we're correctly aligning functions as will be necessary for
ftrace in subsequent patches.

Follow the example of x86, and align assembly functions in the same way
as C functions. Selecting FUNCTION_ALIGNMENT_4B ensures
CONFIG_FUCTION_ALIGNMENT will be a minimum of 4 bytes, matching the
minimum alignment that __ALIGN and __ALIGN_STR provide prior to this
patch.

I've tested this by selecting CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_64B=y,
building and booting a kernel, and looking for misaligned text symbols:

Before, v6.2-rc3:
  # uname -rm
  6.2.0-rc3 aarch64
  # grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
  5009

Before, v6.2-rc3 + fixed __cold:
  # uname -rm
  6.2.0-rc3-00001-g2a2bedf8bfa9 aarch64
  # grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
  919

Before, v6.2-rc3 + fixed __cold + fixed ACPICA:
  # uname -rm
  6.2.0-rc3-00002-g267bddc38572 aarch64
  # grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
  323
  # grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | grep acpi | wc -l
  0

After:
  # uname -rm
  6.2.0-rc3-00003-g71db61ee3ea1 aarch64
  # grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
  112

Considering the remaining 112 unaligned text symbols:

* 20 are non-function KVM NVHE assembly symbols, which are never
  instrumented by ftrace:

  # grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | grep __kvm_nvhe | wc -l
  20
  # grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | grep __kvm_nvhe
  ffffbe6483f73784 t __kvm_nvhe___invalid
  ffffbe6483f73788 t __kvm_nvhe___do_hyp_init
  ffffbe6483f73ab0 t __kvm_nvhe_reset
  ffffbe6483f73b8c T __kvm_nvhe___hyp_idmap_text_end
  ffffbe6483f73b8c T __kvm_nvhe___hyp_text_start
  ffffbe6483f77864 t __kvm_nvhe___host_enter_restore_full
  ffffbe6483f77874 t __kvm_nvhe___host_enter_for_panic
  ffffbe6483f778a4 t __kvm_nvhe___host_enter_without_restoring
  ffffbe6483f81178 T __kvm_nvhe___guest_exit_panic
  ffffbe6483f811c8 T __kvm_nvhe___guest_exit
  ffffbe6483f81354 t __kvm_nvhe_abort_guest_exit_start
  ffffbe6483f81358 t __kvm_nvhe_abort_guest_exit_end
  ffffbe6483f81830 t __kvm_nvhe_wa_epilogue
  ffffbe6483f81844 t __kvm_nvhe_el1_trap
  ffffbe6483f81864 t __kvm_nvhe_el1_fiq
  ffffbe6483f81864 t __kvm_nvhe_el1_irq
  ffffbe6483f81884 t __kvm_nvhe_el1_error
  ffffbe6483f818a4 t __kvm_nvhe_el2_sync
  ffffbe6483f81920 t __kvm_nvhe_el2_error
  ffffbe6483f865c8 T __kvm_nvhe___start___kvm_ex_table

* 53 are position-independent functions only used during early boot, which are
  built with '-Os', but are never instrumented by ftrace:

  # grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | grep __pi | wc -l
  53

  We *could* drop '-Os' when building these for consistency, but that is
  not necessary to ensure that ftrace works correctly.

* The remaining 39 are non-function symbols, and 3 runtime BPF
  functions, which are never instrumented by ftrace:

  # grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | grep -v __kvm_nvhe | grep -v __pi | wc -l
  39
  # grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | grep -v __kvm_nvhe | grep -v __pi
  ffffbe6482e1009c T __irqentry_text_end
  ffffbe6482e10358 T __softirqentry_text_end
  ffffbe6482e1435c T __entry_text_end
  ffffbe6482e825f8 T __guest_exit_panic
  ffffbe6482e82648 T __guest_exit
  ffffbe6482e827d4 t abort_guest_exit_start
  ffffbe6482e827d8 t abort_guest_exit_end
  ffffbe6482e83030 t wa_epilogue
  ffffbe6482e83044 t el1_trap
  ffffbe6482e83064 t el1_fiq
  ffffbe6482e83064 t el1_irq
  ffffbe6482e83084 t el1_error
  ffffbe6482e830a4 t el2_sync
  ffffbe6482e83120 t el2_error
  ffffbe6482e93550 T sha256_block_neon
  ffffbe64830f3ae0 t e843419@01cc_00002a0c_3104
  ffffbe648378bd90 t e843419@09b3_0000d7cb_bc4
  ffffbe6483bdab20 t e843419@0c66_000116e2_34c8
  ffffbe6483f62c94 T __noinstr_text_end
  ffffbe6483f70a18 T __sched_text_end
  ffffbe6483f70b2c T __cpuidle_text_end
  ffffbe6483f722d4 T __lock_text_end
  ffffbe6483f73b8c T __hyp_idmap_text_end
  ffffbe6483f73b8c T __hyp_text_start
  ffffbe6483f865c8 T __start___kvm_ex_table
  ffffbe6483f870d0 t init_el1
  ffffbe6483f870f8 t init_el2
  ffffbe6483f87324 t pen
  ffffbe6483f87b48 T __idmap_text_end
  ffffbe64848eb010 T __hibernate_exit_text_start
  ffffbe64848eb124 T __hibernate_exit_text_end
  ffffbe64848eb124 T __relocate_new_kernel_start
  ffffbe64848eb260 T __relocate_new_kernel_end
  ffffbe648498a8e8 T _einittext
  ffffbe648498a8e8 T __exittext_begin
  ffffbe6484999d84 T __exittext_end
  ffff8000080756b4 t bpf_prog_6deef7357e7b4530    [bpf]
  ffff80000808dd78 t bpf_prog_6deef7357e7b4530    [bpf]
  ffff80000809d684 t bpf_prog_6deef7357e7b4530    [bpf]

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Florent Revest &lt;revest@chromium.org&gt;
Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20230123134603.1064407-5-mark.rutland@arm.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
</entry>
<entry>
<title>arm64: make ARCH_FORCE_MAX_ORDER selectable</title>
<updated>2023-01-12T16:45:05+00:00</updated>
<author>
<name>Kefeng Wang</name>
<email>wangkefeng.wang@huawei.com</email>
</author>
<published>2023-01-04T13:00:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=5a4c2a314083b07751c3151baf5e6ed7cc3aba36'/>
<id>urn:sha1:5a4c2a314083b07751c3151baf5e6ed7cc3aba36</id>
<content type='text'>
The other architectures with ARCH_FORCE_MAX_ORDER are selectable,
but not for ARM64, this is to make it selectable on ARM64, which
is useful for user that need to allocate more than 4MB of physically
contiguous memory with 4K pagesize, also bigger on 16K pagesize too, the
max value of MAX_ORDER is calculated bellow,

see include/linux/mmzone.h,

  MAX_ORDER - 1 + PAGE_SHIFT &lt;= SECTION_SIZE_BITS

  so max value of MAX_ORDER = SECTION_SIZE_BITS + 1 - PAGE_SHIFT

    | SECTION_SIZE_BITS |  PAGE_SHIFT  |  max MAX_ORDER  |  default MAX_ORDER |
----+-------------------+--------------+-----------------+--------------------+
4K  |       27          |      12      |     16          |      11            |
16K |       27          |      14      |     14          |      12            |
64K |       29          |      16      |     14          |      14            |
----+-------------------+--------------+-----------------+--------------------+

Signed-off-by: Kefeng Wang &lt;wangkefeng.wang@huawei.com&gt;
Link: https://lore.kernel.org/r/20230104130000.69806-1-wangkefeng.wang@huawei.com
[catalin.marinas@arm.com: add the calculations as comment to arch/arm64/Kconfig]
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
</entry>
</feed>
