[PATCH 0/5] Add support for FEAT_{LS64, LS64_V, LS64_ACCDATA} and related tests

[Yicong Yang]

From: Yicong Yang <yangyicong at hisilicon.com>

Armv8.7 introduces single-copy atomic 64-byte loads and stores
instructions and its variants named under FEAT_{LS64, LS64_V,
LS64_ACCDATA}. Add support for Armv8.7 FEAT_{LS64, LS64_V, LS64_ACCDATA}:
- Add identifying and enabling in the cpufeature list
- Expose the support of these features to userspace through HWCAP3
  and cpuinfo
- Add related hwcap test
- Handle the trap of unsupported memory (normal/uncacheable) access in a VM

A real scenario for this feature is that the userspace driver can make use of
this to implement direct WQE (workqueue entry) - a mechanism to fill WQE
directly into the hardware.

This patchset also depends on Marc's patchset[1] for enabling related
features in a VM, HCRX trap handling, etc.

[1] https://lore.kernel.org/linux-arm-kernel/20240815125959.2097734-1-maz@kernel.org/

Tested with updated hwcap test:
On host:
root at localhost:/# dmesg | grep "All CPU(s) started"
[    1.600263] CPU: All CPU(s) started at EL2
root at localhost:/# ./hwcap
[snip...]
# LS64 present          
ok 169 cpuinfo_match_LS64
ok 170 sigill_LS64
ok 171 # SKIP sigbus_LS64
# LS64_V present
ok 172 cpuinfo_match_LS64_V
ok 173 sigill_LS64_V
ok 174 # SKIP sigbus_LS64_V
# LS64_ACCDATA present
ok 175 cpuinfo_match_LS64_ACCDATA
ok 176 sigill_LS64_ACCDATA
ok 177 # SKIP sigbus_LS64_ACCDATA
# Totals: pass:92 fail:0 xfail:0 xpass:0 skip:85 error:0

On guest:
root at localhost:/# dmesg | grep "All CPU(s) started"
[    1.375272] CPU: All CPU(s) started at EL1 
root at localhost:/# ./hwcap
[snip...]
# LS64 present
ok 169 cpuinfo_match_LS64
ok 170 sigill_LS64
ok 171 # SKIP sigbus_LS64
# LS64_V present
ok 172 cpuinfo_match_LS64_V
ok 173 sigill_LS64_V
ok 174 # SKIP sigbus_LS64_V
# LS64_ACCDATA present
ok 175 cpuinfo_match_LS64_ACCDATA
ok 176 sigill_LS64_ACCDATA
ok 177 # SKIP sigbus_LS64_ACCDATA
# Totals: pass:92 fail:0 xfail:0 xpass:0 skip:85 error:0

Yicong Yang (5):
  arm64: Provide basic EL2 setup for FEAT_{LS64, LS64_V, LS64_ACCDATA}
    usage at EL0/1
  arm64: Add support for FEAT_{LS64, LS64_V, LS64_ACCDATA}
  kselftest/arm64: Add HWCAP test for FEAT_{LS64, LS64_V, LS64_ACCDATA}
  arm64: Add ESR.DFSC definition of unsupported exclusive or atomic
    access
  KVM: arm64: Handle DABT caused by LS64* instructions on unsupported
    memory

 Documentation/arch/arm64/booting.rst      |  28 +++++
 Documentation/arch/arm64/elf_hwcaps.rst   |   9 ++
 arch/arm64/include/asm/el2_setup.h        |  26 ++++-
 arch/arm64/include/asm/esr.h              |   8 ++
 arch/arm64/include/asm/hwcap.h            |   3 +
 arch/arm64/include/uapi/asm/hwcap.h       |   3 +
 arch/arm64/kernel/cpufeature.c            |  70 +++++++++++-
 arch/arm64/kernel/cpuinfo.c               |   3 +
 arch/arm64/kvm/mmu.c                      |  14 +++
 arch/arm64/tools/cpucaps                  |   3 +
 tools/testing/selftests/arm64/abi/hwcap.c | 127 ++++++++++++++++++++++
 11 files changed, 291 insertions(+), 3 deletions(-)

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2.24.0