> On 14. Oct 2026, at 21:52, Brian Cain <[email protected]> wrote:
>
> v83 and v85 introduce new ISA extensions:
> - CFI/restricted branches
> - scalar atomic operations
Hi,
Probably not possible to emulate nicely but the TRM for those says:
> V85 ERRATA: Atomicity may be lost if a competing instruction is not an
> atomic. To guarantee atomicity, only atomic instructions should be used for
> the memory location
Given that is it expected to be used on v85? Or is it a footgun best unexposed
for that generation?
Would also note that the user-mode DMA spec is still behind the NDA wall, which
makes no sense whatsoever when everybody on the platform is using it anyway...
> - scalar float operations
> - trap2 instruction
> - vector stack, used by HLX
>
> The HLX vector coprocessor, also introduced by these new revisions, is
> not included in this series.
>
> The cross-toolchain doesn't yet support these opcodes. So in our tests,
> we've manually encoded the instructions using ".word" directives and we
> invoke the tests with the explicit '-cpu'. The directives will be replaced
> with the mnemonics and explicit '-cpu' removed once the assembler has the
> necessary support. I expect LLVM 24.x will include these instructions.
>
> Brian Cain (12):
> target/hexagon: sort tag_rev_info entries by version
> Hexagon: add v85 CPU model
> hw/hexagon: add v85 machines
> linux-user/hexagon: report ISA HWCAP through v85
> target/hexagon: add v85 scalar atomics
> target/hexagon: add v83 trap2 and vector stack instructions
> target/hexagon: generate vector frame instructions with IDEF parser
> target/hexagon: reject reserved L4_loadw_phys encoding from v83
> target/hexagon: preserve callr target when Rs is LR
> target/hexagon: implement control flow integrity (CFI)
> target/hexagon: add vsf* instructions
> tests/tcg/hexagon: add v85 scalar tests
>
> docs/system/hexagon/emulation.rst | 2 +-
> include/hw/hexagon/hexagon.h | 6 +-
> linux-user/hexagon/target_elf.h | 2 +
> target/hexagon/cpu-qom.h | 4 +
> target/hexagon/cpu.h | 3 +
> target/hexagon/cpu_bits.h | 2 +
> target/hexagon/gen_tcg.h | 93 +++++++++++-
> target/hexagon/gen_tcg_sys.h | 6 +
> target/hexagon/genptr.h | 12 ++
> target/hexagon/helper.h | 5 +
> target/hexagon/hex_regs.h | 2 +
> target/hexagon/idef-parser/parser-helpers.h | 1 +
> target/hexagon/macros.h | 12 ++
> target/hexagon/translate.h | 4 +
> tests/tcg/hexagon/cfi_tgts.h | 16 ++
> hw/hexagon/machine_cfg_v85na_1.h.inc | 50 +++++++
> hw/hexagon/machine_cfg_v85qa_1.h.inc | 51 +++++++
> target/hexagon/attribs_def.h.inc | 2 +
> target/hexagon/reg_fields_def.h.inc | 1 +
> hw/hexagon/hexagon_dsp.c | 48 +++++-
> linux-user/hexagon/cpu_loop.c | 10 ++
> linux-user/hexagon/elfload.c | 10 ++
> target/hexagon/cpu.c | 10 +-
> target/hexagon/decode.c | 5 +
> target/hexagon/genptr.c | 95 +++++++++++-
> target/hexagon/hex_interrupts.c | 3 +
> target/hexagon/hexswi.c | 16 ++
> target/hexagon/idef-parser/parser-helpers.c | 14 ++
> target/hexagon/machine.c | 3 +-
> target/hexagon/op_helper.c | 73 +++++++++
> target/hexagon/translate.c | 53 ++++++-
> tests/tcg/hexagon/atomics.c | 102 +++++++++++++
> tests/tcg/hexagon/cfi_user.c | 63 ++++++++
> tests/tcg/hexagon/check_rev_gating.c | 10 ++
> tests/tcg/hexagon/invalid-encoding.c | 20 +++
> tests/tcg/hexagon/trap2.c | 34 +++++
> tests/tcg/hexagon/v83_scalar_fp.c | 98 ++++++++++++
> tests/tcg/hexagon/vallocframe.c | 111 ++++++++++++++
> target/hexagon/tag_rev_info.c.inc | 82 ++++++++--
> target/hexagon/gen_idef_parser_funcs.py | 4 +-
> target/hexagon/idef-parser/idef-parser.lex | 8 +
> target/hexagon/idef-parser/idef-parser.y | 9 +-
> target/hexagon/imported/alu.idef | 3 +
> target/hexagon/imported/branch.idef | 38 +++++
> target/hexagon/imported/encode_pp.def | 43 +++++-
> target/hexagon/imported/encode_subinsn.def | 1 +
> target/hexagon/imported/float.idef | 49 ++++++
> target/hexagon/imported/ldst.idef | 15 ++
> target/hexagon/imported/macros.def | 10 ++
> target/hexagon/imported/subinsns.idef | 2 +
> target/hexagon/imported/system.idef | 9 ++
> tests/tcg/hexagon/cfi_tgts.S | 157 ++++++++++++++++++++
> tests/tcg/hexagon/meson.build | 19 ++-
> 53 files changed, 1470 insertions(+), 31 deletions(-)
> create mode 100644 tests/tcg/hexagon/cfi_tgts.h
> create mode 100644 hw/hexagon/machine_cfg_v85na_1.h.inc
> create mode 100644 hw/hexagon/machine_cfg_v85qa_1.h.inc
> create mode 100644 tests/tcg/hexagon/cfi_user.c
> create mode 100644 tests/tcg/hexagon/trap2.c
> create mode 100644 tests/tcg/hexagon/v83_scalar_fp.c
> create mode 100644 tests/tcg/hexagon/vallocframe.c
> create mode 100644 tests/tcg/hexagon/cfi_tgts.S
>
> --
> 2.34.1
>
