Re: [RFC V2] RISC-V : Support rv64 ilp32
On Mon, May 22, 2023 at 10:51 AM Guo Ren wrote:
>
> On Fri, May 19, 2023 at 3:35 PM Kito Cheng wrote:
> >
> > I am concern about we didn't define POINTERS_EXTEND_UNSIGNED here, and
> > also concern about the code model stuffs, I know currently Guo-Ren's
> > implementation is rely on some MMU trick, but I am not sure does it
> > also applicable on embedded applications.
> There are two ways:
> - Limit address < 2GB. (Fortunately, most MCUs have a limit on their
> address of less than 2GB.)
> - The zjpm liked hardware extension could mask the highest 32 bits of the
> address.
I guess your question is: Shall we start the work of the GCC's
POINTERS_EXTEND_UNSIGNED?
If the SoC's start address of dram > 2GB, we need the GCC's
POINTERS_EXTEND_UNSIGNED.
>
> >
> >
> > > diff --git a/gcc/config/riscv/linux.h b/gcc/config/riscv/linux.h
> > > index b9557a75dc7..4f33c88ef6e 100644
> > > --- a/gcc/config/riscv/linux.h
> > > +++ b/gcc/config/riscv/linux.h
> > > @@ -58,7 +58,7 @@ along with GCC; see the file COPYING3. If not see
> > >"%{mabi=ilp32:_ilp32}"
> > >
> > > #define LINK_SPEC "\
> > > --melf" XLEN_SPEC DEFAULT_ENDIAN_SPEC "riscv" LD_EMUL_SUFFIX " \
> > > +-melf" ABI_LEN_SPEC DEFAULT_ENDIAN_SPEC "riscv" LD_EMUL_SUFFIX " \
> > > %{mno-relax:--no-relax} \
> > > %{mbig-endian:-EB} \
> > > %{mlittle-endian:-EL} \
> > > diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
> > > index 5f44f6dc5c9..09ab940447d 100644
> > > --- a/gcc/config/riscv/riscv.cc
> > > +++ b/gcc/config/riscv/riscv.cc
> > > @@ -6291,10 +6291,6 @@ riscv_option_override (void)
> > >&& riscv_abi != ABI_LP64 && riscv_abi != ABI_ILP32E)
> > > error ("z*inx requires ABI ilp32, ilp32e or lp64");
> > >
> > > - /* We do not yet support ILP32 on RV64. */
> > > - if (BITS_PER_WORD != POINTER_SIZE)
> > > -error ("ABI requires %<-march=rv%d%>", POINTER_SIZE);
> >
> > It seems to also make -march=rv32g -mabi=lp64 become acceptable?
> >
> > >
>
>
>
> --
> Best Regards
> Guo Ren
--
Best Regards
Guo Ren
Re: [RFC V2] RISC-V : Support rv64 ilp32
On Fri, May 19, 2023 at 3:35 PM Kito Cheng wrote:
>
> I am concern about we didn't define POINTERS_EXTEND_UNSIGNED here, and
> also concern about the code model stuffs, I know currently Guo-Ren's
> implementation is rely on some MMU trick, but I am not sure does it
> also applicable on embedded applications.
There are two ways:
- Limit address < 2GB. (Fortunately, most MCUs have a limit on their
address of less than 2GB.)
- The zjpm liked hardware extension could mask highest 32 bits of the address.
>
>
> > diff --git a/gcc/config/riscv/linux.h b/gcc/config/riscv/linux.h
> > index b9557a75dc7..4f33c88ef6e 100644
> > --- a/gcc/config/riscv/linux.h
> > +++ b/gcc/config/riscv/linux.h
> > @@ -58,7 +58,7 @@ along with GCC; see the file COPYING3. If not see
> >"%{mabi=ilp32:_ilp32}"
> >
> > #define LINK_SPEC "\
> > --melf" XLEN_SPEC DEFAULT_ENDIAN_SPEC "riscv" LD_EMUL_SUFFIX " \
> > +-melf" ABI_LEN_SPEC DEFAULT_ENDIAN_SPEC "riscv" LD_EMUL_SUFFIX " \
> > %{mno-relax:--no-relax} \
> > %{mbig-endian:-EB} \
> > %{mlittle-endian:-EL} \
> > diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
> > index 5f44f6dc5c9..09ab940447d 100644
> > --- a/gcc/config/riscv/riscv.cc
> > +++ b/gcc/config/riscv/riscv.cc
> > @@ -6291,10 +6291,6 @@ riscv_option_override (void)
> >&& riscv_abi != ABI_LP64 && riscv_abi != ABI_ILP32E)
> > error ("z*inx requires ABI ilp32, ilp32e or lp64");
> >
> > - /* We do not yet support ILP32 on RV64. */
> > - if (BITS_PER_WORD != POINTER_SIZE)
> > -error ("ABI requires %<-march=rv%d%>", POINTER_SIZE);
>
> It seems to also make -march=rv32g -mabi=lp64 become acceptable?
>
> >
--
Best Regards
Guo Ren
Re: [RFC V2] RISC-V : Support rv64 ilp32
Thanks for your advice, Kito.
在 2023/5/19 15:35, Kito Cheng 写道:
I am concern about we didn't define POINTERS_EXTEND_UNSIGNED here, and
also concern about the code model stuffs, I know currently Guo-Ren's
implementation is rely on some MMU trick, but I am not sure does it
also applicable on embedded applications.
OK，we will verify this in the future.
- /* We do not yet support ILP32 on RV64. */
- if (BITS_PER_WORD != POINTER_SIZE)
-error ("ABI requires %<-march=rv%d%>", POINTER_SIZE);
It seems to also make -march=rv32g -mabi=lp64 become acceptable?
Oh, I was negligent and will make improvements in the next patch.
Best Regards
Liao Shihua
Re: [RFC V2] RISC-V : Support rv64 ilp32
I am concern about we didn't define POINTERS_EXTEND_UNSIGNED here, and
also concern about the code model stuffs, I know currently Guo-Ren's
implementation is rely on some MMU trick, but I am not sure does it
also applicable on embedded applications.
> diff --git a/gcc/config/riscv/linux.h b/gcc/config/riscv/linux.h
> index b9557a75dc7..4f33c88ef6e 100644
> --- a/gcc/config/riscv/linux.h
> +++ b/gcc/config/riscv/linux.h
> @@ -58,7 +58,7 @@ along with GCC; see the file COPYING3. If not see
>"%{mabi=ilp32:_ilp32}"
>
> #define LINK_SPEC "\
> --melf" XLEN_SPEC DEFAULT_ENDIAN_SPEC "riscv" LD_EMUL_SUFFIX " \
> +-melf" ABI_LEN_SPEC DEFAULT_ENDIAN_SPEC "riscv" LD_EMUL_SUFFIX " \
> %{mno-relax:--no-relax} \
> %{mbig-endian:-EB} \
> %{mlittle-endian:-EL} \
> diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
> index 5f44f6dc5c9..09ab940447d 100644
> --- a/gcc/config/riscv/riscv.cc
> +++ b/gcc/config/riscv/riscv.cc
> @@ -6291,10 +6291,6 @@ riscv_option_override (void)
>&& riscv_abi != ABI_LP64 && riscv_abi != ABI_ILP32E)
> error ("z*inx requires ABI ilp32, ilp32e or lp64");
>
> - /* We do not yet support ILP32 on RV64. */
> - if (BITS_PER_WORD != POINTER_SIZE)
> -error ("ABI requires %<-march=rv%d%>", POINTER_SIZE);
It seems to also make -march=rv32g -mabi=lp64 become acceptable?
>
