By comparing the swapper_pg_dir with k54 and previous versions,we find
that the linear mappings within which the addr is out of kernel text section
will use the smallest pte. It should arise for the sake of rodata_full, which
set all memblock use NO_CONT_MAPPINGS.

Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>

gcc warns about undefined behavior the vmalloc code when building
with CONFIG_ARM64_PA_BITS_52, when the 'idx++' in the argument to
__phys_to_pte_val() is evaluated twice:

mm/vmalloc.c: In function 'vmap_pfn_apply':
mm/vmalloc.c:2800:58: error: operation on 'data->idx' may be undefined [-Werror=sequence-point]
 2800 |         *pte = pte_mkspecial(pfn_pte(data->pfns[data->idx++], data->prot));
      |                                                 ~~~~~~~~~^~
arch/arm64/include/asm/pgtable-types.h:25:37: note: in definition of macro '__pte'
   25 | #define __pte(x)        ((pte_t) { (x) } )
      |                                     ^
arch/arm64/include/asm/pgtable.h:80:15: note: in expansion of macro '__phys_to_pte_val'
   80 |         __pte(__phys_to_pte_val((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot))
      |               ^~~~~~~~~~~~~~~~~
mm/vmalloc.c:2800:30: note: in expansion of macro 'pfn_pte'
 2800 |         *pte = pte_mkspecial(pfn_pte(data->pfns[data->idx++], data->prot));
      |                              ^~~~~~~

I have no idea why this never showed up earlier, but the safest
workaround appears to be changing those macros into inline functions
so the arguments get evaluated only once.

Cc: Matthew Wilcox <willy@infradead.org>
Fixes: 75387b9 ("arm64: handle 52-bit physical addresses in page table entries")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20211105075414.2553155-1-arnd@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

After switched page size from 64KB to 4KB on several arm64 servers here,
kmemleak starts to run out of early memory pool due to a huge number of
those early_pgtable_alloc() calls:

  kmemleak_alloc_phys()
  memblock_alloc_range_nid()
  memblock_phys_alloc_range()
  early_pgtable_alloc()
  init_pmd()
  alloc_init_pud()
  __create_pgd_mapping()
  __map_memblock()
  paging_init()
  setup_arch()
  start_kernel()

Increased the default value of DEBUG_KMEMLEAK_MEM_POOL_SIZE by 4 times
won't be enough for a server with 200GB+ memory. There isn't much
interesting to check memory leaks for those early page tables and those
early memory mappings should not reference to other memory. Hence, no
kmemleak false positives, and we can safely skip tracking those early
allocations from kmemleak like we did in the commit fed84c7
("mm/memblock.c: skip kmemleak for kasan_init()") without needing to
introduce complications to automatically scale the value depends on the
runtime memory size etc. After the patch, the default value of
DEBUG_KMEMLEAK_MEM_POOL_SIZE becomes sufficient again.

Signed-off-by: Qian Cai <quic_qiancai@quicinc.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Link: https://lore.kernel.org/r/20211105150509.7826-1-quic_qiancai@quicinc.com
Signed-off-by: Will Deacon <will@kernel.org>

This constant was previously an unsigned long, but was changed
into an int in commit 433c38f ("arm64: mte: change ASYNC and
SYNC TCF settings into bitfields"). This ended up causing spurious
unsigned-signed comparison warnings in expressions such as:

(x & PR_MTE_TCF_MASK) != PR_MTE_TCF_NONE

Therefore, change it back into an unsigned long to silence these
warnings.

Link: https://linux-review.googlesource.com/id/I07a72310db30227a5b7d789d0b817d78b657c639
Signed-off-by: Peter Collingbourne <pcc@google.com>
Link: https://lore.kernel.org/r/20211105230829.2254790-1-pcc@google.com
Signed-off-by: Will Deacon <will@kernel.org>

The -nostdlib option requests the compiler to not use the standard
system startup files or libraries when linking. It is effective only
when $(CC) is used as a linker driver.

Since commit 691efbe ("arm64: vdso: use $(LD) instead of $(CC)
to link VDSO"), $(LD) is directly used, hence -nostdlib is unneeded.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20211107161802.323125-1-masahiroy@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

The id argument of ARM64_FTR_REG_OVERRIDE() is used for two purposes:
one as the system register encoding (used for the sys_id field of
__ftr_reg_entry), and the other as the register name (stringified
and used for the name field of arm64_ftr_reg), which is debug
information. The id argument is supposed to be a macro that
indicates an encoding of the register (eg. SYS_ID_AA64PFR0_EL1, etc).

ARM64_FTR_REG(), which also has the same id argument,
uses ARM64_FTR_REG_OVERRIDE() and passes the id to the macro.
Since the id argument is completely macro-expanded before it is
substituted into a macro body of ARM64_FTR_REG_OVERRIDE(),
the stringified id in the body of ARM64_FTR_REG_OVERRIDE is not
a human-readable register name, but a string of numeric bitwise
operations.

Fix this so that human-readable register names are available as
debug information.

Fixes: 8f266a5 ("arm64: cpufeature: Add global feature override facility")
Signed-off-by: Reiji Watanabe <reijiw@google.com>
Reviewed-by: Oliver Upton <oupton@google.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211101045421.2215822-1-reijiw@google.com
Signed-off-by: Will Deacon <will@kernel.org>

Merge for-next/fixes to resolve conflicts in arm64_hugetlb_cma_reserve().

* for-next/fixes:
  acpi/arm64: fix next_platform_timer() section mismatch error
  arm64/hugetlb: fix CMA gigantic page order for non-4K PAGE_SIZE

* for-next/vdso:
  arm64: vdso32: require CROSS_COMPILE_COMPAT for gcc+bfd
  arm64: vdso32: suppress error message for 'make mrproper'
  arm64: vdso32: drop test for -march=armv8-a
  arm64: vdso32: drop the test for dmb ishld

* for-next/trbe-errata:
  arm64: errata: Add detection for TRBE write to out-of-range
  arm64: errata: Add workaround for TSB flush failures
  arm64: errata: Add detection for TRBE overwrite in FILL mode
  arm64: Add Neoverse-N2, Cortex-A710 CPU part definition

* for-next/sve:
  arm64/sve: Fix warnings when SVE is disabled
  arm64/sve: Add stub for sve_max_virtualisable_vl()
  arm64/sve: Track vector lengths for tasks in an array
  arm64/sve: Explicitly load vector length when restoring SVE state
  arm64/sve: Put system wide vector length information into structs
  arm64/sve: Use accessor functions for vector lengths in thread_struct
  arm64/sve: Rename find_supported_vector_length()
  arm64/sve: Make access to FFR optional
  arm64/sve: Make sve_state_size() static
  arm64/sve: Remove sve_load_from_fpsimd_state()
  arm64/fp: Reindent fpsimd_save()

* for-next/scs:
  scs: Release kasan vmalloc poison in scs_free process

* for-next/pfn-valid:
  arm64/mm: drop HAVE_ARCH_PFN_VALID
  dma-mapping: remove bogus test for pfn_valid from dma_map_resource

* for-next/perf:
  drivers/perf: Improve build test coverage
  drivers/perf: thunderx2_pmu: Change data in size tx2_uncore_event_update()
  drivers/perf: hisi: Fix PA PMU counter offset

* for-next/mte:
  kasan: Extend KASAN mode kernel parameter
  arm64: mte: Add asymmetric mode support
  arm64: mte: CPU feature detection for Asymm MTE
  arm64: mte: Bitfield definitions for Asymm MTE
  kasan: Remove duplicate of kasan_flag_async
  arm64: kasan: mte: move GCR_EL1 switch to task switch when KASAN disabled

* for-next/mm:
  arm64: mm: update max_pfn after memory hotplug
  arm64/mm: Add pud_sect_supported()
  arm64: mm: Drop pointless call to set_max_mapnr()

* for-next/misc:
  arm64: Select POSIX_CPU_TIMERS_TASK_WORK
  arm64: Document boot requirements for FEAT_SME_FA64
  arm64: ftrace: use function_nocfi for _mcount as well
  arm64: asm: setup.h: export common variables
  arm64/traps: Avoid unnecessary kernel/user pointer conversion

* for-next/kselftest:
  selftests: arm64: Factor out utility functions for assembly FP tests
  selftests: arm64: Add coverage of ptrace flags for SVE VL inheritance
  selftests: arm64: Verify that all possible vector lengths are handled
  selftests: arm64: Fix and enable test for setting current VL in vec-syscfg
  selftests: arm64: Remove bogus error check on writing to files
  selftests: arm64: Fix printf() format mismatch in vec-syscfg
  selftests: arm64: Move FPSIMD in SVE ptrace test into a function
  selftests: arm64: More comprehensively test the SVE ptrace interface
  selftests: arm64: Verify interoperation of SVE and FPSIMD register sets
  selftests: arm64: Clarify output when verifying SVE register set
  selftests: arm64: Document what the SVE ptrace test is doing
  selftests: arm64: Remove extraneous register setting code
  selftests: arm64: Don't log child creation as a test in SVE ptrace test
  selftests: arm64: Use a define for the number of SVE ptrace tests to be run

* for-next/kexec:
  arm64: trans_pgd: remove trans_pgd_map_page()
  arm64: kexec: remove cpu-reset.h
  arm64: kexec: remove the pre-kexec PoC maintenance
  arm64: kexec: keep MMU enabled during kexec relocation
  arm64: kexec: install a copy of the linear-map
  arm64: kexec: use ld script for relocation function
  arm64: kexec: relocate in EL1 mode
  arm64: kexec: configure EL2 vectors for kexec
  arm64: kexec: pass kimage as the only argument to relocation function
  arm64: kexec: Use dcache ops macros instead of open-coding
  arm64: kexec: skip relocation code for inplace kexec
  arm64: kexec: flush image and lists during kexec load time
  arm64: hibernate: abstract ttrb0 setup function
  arm64: trans_pgd: hibernate: Add trans_pgd_copy_el2_vectors
  arm64: kernel: add helper for booted at EL2 and not VHE

* for-next/extable:
  arm64: vmlinux.lds.S: remove `.fixup` section
  arm64: extable: add load_unaligned_zeropad() handler
  arm64: extable: add a dedicated uaccess handler
  arm64: extable: add `type` and `data` fields
  arm64: extable: use `ex` for `exception_table_entry`
  arm64: extable: make fixup_exception() return bool
  arm64: extable: consolidate definitions
  arm64: gpr-num: support W registers
  arm64: factor out GPR numbering helpers
  arm64: kvm: use kvm_exception_table_entry
  arm64: lib: __arch_copy_to_user(): fold fixups into body
  arm64: lib: __arch_copy_from_user(): fold fixups into body
  arm64: lib: __arch_clear_user(): fold fixups into body

* for-next/8.6-timers:
  arm64: Add HWCAP for self-synchronising virtual counter
  arm64: Add handling of CNTVCTSS traps
  arm64: Add CNT{P,V}CTSS_EL0 alternatives to cnt{p,v}ct_el0
  arm64: Add a capability for FEAT_ECV
  clocksource/drivers/arch_arm_timer: Move workaround synchronisation around
  clocksource/drivers/arm_arch_timer: Fix masking for high freq counters
  clocksource/drivers/arm_arch_timer: Drop unnecessary ISB on CVAL programming
  clocksource/drivers/arm_arch_timer: Remove any trace of the TVAL programming interface
  clocksource/drivers/arm_arch_timer: Work around broken CVAL implementations
  clocksource/drivers/arm_arch_timer: Advertise 56bit timer to the core code
  clocksource/drivers/arm_arch_timer: Move MMIO timer programming over to CVAL
  clocksource/drivers/arm_arch_timer: Fix MMIO base address vs callback ordering issue
  clocksource/drivers/arm_arch_timer: Move drop _tval from erratum function names
  clocksource/drivers/arm_arch_timer: Move system register timer programming over to CVAL
  clocksource/drivers/arm_arch_timer: Extend write side of timer register accessors to u64
  clocksource/drivers/arm_arch_timer: Drop CNT*_TVAL read accessors
  clocksource/arm_arch_timer: Add build-time guards for unhandled register accesses

With 6caa581 ("KVM: arm64: Use generic KVM xfer to guest work
function") all arm64 exit paths are properly equipped to handle the
POSIX timers' task work.

Deferring timer callbacks to thread context, not only limits the amount
of time spent in hard interrupt context, but is a safer
implementation[1], and will allow PREEMPT_RT setups to use KVM[2].

So let's enable POSIX_CPU_TIMERS_TASK_WORK on arm64.

[1] https://lore.kernel.org/all/20200716201923.228696399@linutronix.de/
[2] https://lore.kernel.org/linux-rt-users/87v92bdnlx.ffs@tglx/

Signed-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211018144713.873464-1-nsaenzju@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>

The EAC1 release of the SME specification adds the FA64 feature which
requires enablement at higher ELs before lower ELs can use it. Document
what we require from higher ELs in our boot requirements.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20211026111802.12853-1-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

In configurations where SVE is disabled we define but never reference the
functions for retrieving the default vector length, causing warnings. Fix
this by move the ifdef up, marking get_default_vl() inline since it is
referenced from code guarded by an IS_ENABLED() check, and do the same for
the other accessors for consistency.

Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20211022141635.2360415-3-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

Fixes build problems for configurations with KVM enabled but SVE disabled.

Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20211022141635.2360415-2-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

Arm Neoverse-N2 and Cortex-A710 cores are affected by an erratum where
the trbe, under some circumstances, might write upto 64bytes to an
address after the Limit as programmed by the TRBLIMITR_EL1.LIMIT.
This might -
  - Corrupt a page in the ring buffer, which may corrupt trace from a
    previous session, consumed by userspace.
  - Hit the guard page at the end of the vmalloc area and raise a fault.

To keep the handling simpler, we always leave the last page from the
range, which TRBE is allowed to write. This can be achieved by ensuring
that we always have more than a PAGE worth space in the range, while
calculating the LIMIT for TRBE. And then the LIMIT pointer can be
adjusted to leave the PAGE (TRBLIMITR.LIMIT -= PAGE_SIZE), out of the
TRBE range while enabling it. This makes sure that the TRBE will only
write to an area within its allowed limit (i.e, [head-head+size]) and
we do not have to handle address faults within the driver.

Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20211019163153.3692640-5-suzuki.poulose@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

Arm Neoverse-N2 (#2067961) and Cortex-A710 (#2054223) suffers
from errata, where a TSB (trace synchronization barrier)
fails to flush the trace data completely, when executed from
a trace prohibited region. In Linux we always execute it
after we have moved the PE to trace prohibited region. So,
we can apply the workaround every time a TSB is executed.

The work around is to issue two TSB consecutively.

NOTE: This errata is defined as LOCAL_CPU_ERRATUM, implying
that a late CPU could be blocked from booting if it is the
first CPU that requires the workaround. This is because we
do not allow setting a cpu_hwcaps after the SMP boot. The
other alternative is to use "this_cpu_has_cap()" instead
of the faster system wide check, which may be a bit of an
overhead, given we may have to do this in nvhe KVM host
before a guest entry.

Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20211019163153.3692640-4-suzuki.poulose@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

Arm Neoverse-N2 and the Cortex-A710 cores are affected
by a CPU erratum where the TRBE will overwrite the trace buffer
in FILL mode. The TRBE doesn't stop (as expected in FILL mode)
when it reaches the limit and wraps to the base to continue
writing upto 3 cache lines. This will overwrite any trace that
was written previously.

Add the Neoverse-N2 erratum(#2139208) and Cortex-A710 erratum
(#2119858) to the detection logic.

This will be used by the TRBE driver in later patches to work
around the issue. The detection has been kept with the core
arm64 errata framework list to make sure :
  - We don't duplicate the framework in TRBE driver
  - The errata detection is advertised like the rest
    of the CPU errata.

Note that the Kconfig entries are not fully active until the
TRBE driver implements the work around.

Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
cc: Leo Yan <leo.yan@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20211019163153.3692640-3-suzuki.poulose@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

Add the CPU Partnumbers for the new Arm designs.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20211019163153.3692640-2-suzuki.poulose@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

The various floating point test programs written in assembly have a bunch
of helper functions and macros which are cut'n'pasted between them. Factor
them out into a separate source file which is linked into all of them.

We don't include memcmp() since it isn't as generic as it should be and
directly branches to report an error in the programs.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20211019181851.3341232-1-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

We no longer place anything into a `.fixup` section, so we no longer
need to place those sections into the `.text` section in the main kernel
Image.

Remove the use of `.fixup`.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-14-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

For inline assembly, we place exception fixups out-of-line in the
`.fixup` section such that these are out of the way of the fast path.
This has a few drawbacks:

* Since the fixup code is anonymous, backtraces will symbolize fixups as
  offsets from the nearest prior symbol, currently
  `__entry_tramp_text_end`. This is confusing, and painful to debug
  without access to the relevant vmlinux.

* Since the exception handler adjusts the PC to execute the fixup, and
  the fixup uses a direct branch back into the function it fixes,
  backtraces of fixups miss the original function. This is confusing,
  and violates requirements for RELIABLE_STACKTRACE (and therefore
  LIVEPATCH).

* Inline assembly and associated fixups are generated from templates,
  and we have many copies of logically identical fixups which only
  differ in which specific registers are written to and which address is
  branched to at the end of the fixup. This is potentially wasteful of
  I-cache resources, and makes it hard to add additional logic to fixups
  without significant bloat.

* In the case of load_unaligned_zeropad(), the logic in the fixup
  requires a temporary register that we must allocate even in the
  fast-path where it will not be used.

This patch address all four concerns for load_unaligned_zeropad() fixups
by adding a dedicated exception handler which performs the fixup logic
in exception context and subsequent returns back after the faulting
instruction. For the moment, the fixup logic is identical to the old
assembly fixup logic, but in future we could enhance this by taking the
ESR and FAR into account to constrain the faults we try to fix up, or to
specialize fixups for MTE tag check faults.

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

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-13-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

For inline assembly, we place exception fixups out-of-line in the
`.fixup` section such that these are out of the way of the fast path.
This has a few drawbacks:

* Since the fixup code is anonymous, backtraces will symbolize fixups as
  offsets from the nearest prior symbol, currently
  `__entry_tramp_text_end`. This is confusing, and painful to debug
  without access to the relevant vmlinux.

* Since the exception handler adjusts the PC to execute the fixup, and
  the fixup uses a direct branch back into the function it fixes,
  backtraces of fixups miss the original function. This is confusing,
  and violates requirements for RELIABLE_STACKTRACE (and therefore
  LIVEPATCH).

* Inline assembly and associated fixups are generated from templates,
  and we have many copies of logically identical fixups which only
  differ in which specific registers are written to and which address is
  branched to at the end of the fixup. This is potentially wasteful of
  I-cache resources, and makes it hard to add additional logic to fixups
  without significant bloat.

This patch address all three concerns for inline uaccess fixups by
adding a dedicated exception handler which updates registers in
exception context and subsequent returns back into the function which
faulted, removing the need for fixups specialized to each faulting
instruction.

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

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-12-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

Subsequent patches will add specialized handlers for fixups, in addition
to the simple PC fixup and BPF handlers we have today. In preparation,
this patch adds a new `type` field to struct exception_table_entry, and
uses this to distinguish the fixup and BPF cases. A `data` field is also
added so that subsequent patches can associate data specific to each
exception site (e.g. register numbers).

Handlers are named ex_handler_*() for consistency, following the exmaple
of x86. At the same time, get_ex_fixup() is split out into a helper so
that it can be used by other ex_handler_*() functions ins subsequent
patches.

This patch will increase the size of the exception tables, which will be
remedied by subsequent patches removing redundant fixup code. There
should be no functional change as a result of this patch.

Since each entry is now 12 bytes in size, we must reduce the alignment
of each entry from `.align 3` (i.e. 8 bytes) to `.align 2` (i.e. 4
bytes), which is the natrual alignment of the `insn` and `fixup` fields.
The current 8-byte alignment is a holdover from when the `insn` and
`fixup` fields was 8 bytes, and while not harmful has not been necessary
since commit:

  6c94f27 ("arm64: switch to relative exception tables")

Similarly, RO_EXCEPTION_TABLE_ALIGN is dropped to 4 bytes.

Concurrently with this patch, x86's exception table entry format is
being updated (similarly to a 12-byte format, with 32-bytes of absolute
data). Once both have been merged it should be possible to unify the
sorttable logic for the two.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: James Morse <james.morse@arm.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-11-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

Subsequent patches will extend `struct exception_table_entry` with more
fields, and the distinction between the entry and its `fixup` field will
become more important.

For clarity, let's consistently use `ex` to refer to refer to an entire
entry. In subsequent patches we'll use `fixup` to refer to the fixup
field specifically. This matches the naming convention used today in
arch/arm64/net/bpf_jit_comp.c.

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

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-10-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

The return values of fixup_exception() and arm64_bpf_fixup_exception()
represent a boolean condition rather than an error code, so for clarity
it would be better to return `bool` rather than `int`.

This patch adjusts the code accordingly. While we're modifying the
prototype, we also remove the unnecessary `extern` keyword, so that this
won't look out of place when we make subsequent additions to the header.

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

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: James Morse <james.morse@arm.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-9-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>