[PATCH V4] RISC-V: Implement Ztso extension

[Nelson Chu]

Committed, thanks.

Nelson

On Tue, Sep 20, 2022 at 5:46 PM <shihua@iscas.ac.cn> wrote:
>
> From: Shihua <shihua@iscas.ac.cn>
>
>    This patch support ZTSO extension. It will turn on the tso flag for elf_flags once we have enabled Ztso extension.
>    This is intended to implement v0.1 of the proposed specification which can be found in Chapter 25 of https://github.com/riscv/riscv-isa-manual/releases/download/draft-20220723-10eea63/riscv-spec.pdf.
>
> V4:
>    According to Nelson Chu's feedback ( https://sourceware.org/pipermail/binutils/2022-September/122960.html ),
>    * remove support tso for the .option directive
>
> V3:
>    According to Tsukasa OI's feedback ( https://sourceware.org/pipermail/binutils/2022-September/122915.html ),
>    * remove CLASS_INSN_ZTSO because it is not used.
>    * remove testsuite attribute-015.d, because it is not necessary.
>    * add testsuite ztso.d, to verify whether the flag TSO is generated.
>
> bfd\ChangeLog:
>
>         * elfnn-riscv.c (_bfd_riscv_elf_merge_private_bfd_data): Set TSO flag.
>         * elfxx-riscv.c: Add Ztso's arch.
>
> binutils\ChangeLog:
>
>         * readelf.c (get_machine_flags): Set TSO flag.
>
> gas\ChangeLog:
>
>         * config/tc-riscv.c (riscv_set_tso): Ditto.
>         (riscv_set_arch): Ditto.
>         * testsuite/gas/riscv/ztso.d: New test.
>
> include\ChangeLog:
>
>         * elf/riscv.h (EF_RISCV_TSO): Ditto.
>
> ---
>  bfd/elfnn-riscv.c              |  3 +++
>  bfd/elfxx-riscv.c              |  1 +
>  binutils/readelf.c             |  3 +++
>  gas/config/tc-riscv.c          | 11 +++++++++++
>  gas/testsuite/gas/riscv/ztso.d |  8 ++++++++
>  include/elf/riscv.h            |  3 +++
>  6 files changed, 29 insertions(+)
>  create mode 100644 gas/testsuite/gas/riscv/ztso.d
>
> diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c
> index 0e0a0b09e24..3d2ddf4e651 100644
> --- a/bfd/elfnn-riscv.c
> +++ b/bfd/elfnn-riscv.c
> @@ -3872,6 +3872,9 @@ _bfd_riscv_elf_merge_private_bfd_data (bfd *ibfd, struct bfd_link_info *info)
>    /* Allow linking RVC and non-RVC, and keep the RVC flag.  */
>    elf_elfheader (obfd)->e_flags |= new_flags & EF_RISCV_RVC;
>
> +  /* Allow linking TSO and non-TSO, and keep the TSO flag.  */
> +  elf_elfheader (obfd)->e_flags |= new_flags & EF_RISCV_TSO;
> +
>    return true;
>
>   fail:
> diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
> index e03b312a381..7eda177bd6e 100644
> --- a/bfd/elfxx-riscv.c
> +++ b/bfd/elfxx-riscv.c
> @@ -1204,6 +1204,7 @@ static struct riscv_supported_ext riscv_supported_std_z_ext[] =
>    {"zvl16384b",                ISA_SPEC_CLASS_DRAFT,           1, 0,  0 },
>    {"zvl32768b",                ISA_SPEC_CLASS_DRAFT,           1, 0,  0 },
>    {"zvl65536b",                ISA_SPEC_CLASS_DRAFT,           1, 0,  0 },
> +  {"ztso",             ISA_SPEC_CLASS_DRAFT,           0, 1,  0 },
>    {NULL, 0, 0, 0, 0}
>  };
>
> diff --git a/binutils/readelf.c b/binutils/readelf.c
> index cafba9a4f56..b1dbcad06f5 100644
> --- a/binutils/readelf.c
> +++ b/binutils/readelf.c
> @@ -4079,6 +4079,9 @@ get_machine_flags (Filedata * filedata, unsigned e_flags, unsigned e_machine)
>           if (e_flags & EF_RISCV_RVE)
>             strcat (buf, ", RVE");
>
> +         if (e_flags & EF_RISCV_TSO)
> +           strcat (buf, ", TSO");
> +
>           switch (e_flags & EF_RISCV_FLOAT_ABI)
>             {
>             case EF_RISCV_FLOAT_ABI_SOFT:
> diff --git a/gas/config/tc-riscv.c b/gas/config/tc-riscv.c
> index 2f5ee18e451..088f75d6a83 100644
> --- a/gas/config/tc-riscv.c
> +++ b/gas/config/tc-riscv.c
> @@ -257,6 +257,14 @@ riscv_set_rvc (bool rvc_value)
>    riscv_opts.rvc = rvc_value;
>  }
>
> +/* Turn on the tso flag for elf_flags once we have enabled ztso extension.  */
> +
> +static void
> +riscv_set_tso ()
> +{
> +  elf_flags |= EF_RISCV_TSO;
> +}
> +
>  /* This linked list records all enabled extensions, which are parsed from
>     the architecture string.  The architecture string can be set by the
>     -march option, the elf architecture attributes, and the --with-arch
> @@ -307,6 +315,9 @@ riscv_set_arch (const char *s)
>    riscv_set_rvc (false);
>    if (riscv_subset_supports (&riscv_rps_as, "c"))
>      riscv_set_rvc (true);
> +
> +  if (riscv_subset_supports (&riscv_rps_as, "ztso"))
> +    riscv_set_tso ();
>  }
>
>  /* Indicate -mabi option is explictly set.  */
> diff --git a/gas/testsuite/gas/riscv/ztso.d b/gas/testsuite/gas/riscv/ztso.d
> new file mode 100644
> index 00000000000..cb038db89d3
> --- /dev/null
> +++ b/gas/testsuite/gas/riscv/ztso.d
> @@ -0,0 +1,8 @@
> +#as: -march=rv64i_ztso
> +#readelf: -h
> +#source: empty.s
> +
> +ELF Header:
> +#...
> +[      ]+Flags:[       ]+0x10, TSO.*
> +#...
> \ No newline at end of file
> diff --git a/include/elf/riscv.h b/include/elf/riscv.h
> index 9b3ea376ff3..d7b5c09d5c3 100644
> --- a/include/elf/riscv.h
> +++ b/include/elf/riscv.h
> @@ -121,6 +121,9 @@ END_RELOC_NUMBERS (R_RISCV_max)
>  /* RISC-V specific values for st_other.  */
>  #define STO_RISCV_VARIANT_CC 0x80
>
> +/* File uses the TSO model. */
> +#define EF_RISCV_TSO 0x0010
> +
>  /* Additional section types.  */
>  #define SHT_RISCV_ATTRIBUTES 0x70000003 /* Section holds attributes.  */
>
> --
> 2.37.1.windows.1
>