[PATCH V6 16/20] riscv: compat: vdso: Add rv32 VDSO base code implementation

[Arnd Bergmann]

On Fri, Feb 25, 2022 at 4:42 PM Guo Ren <guoren at kernel.org> wrote:
>
> Hi Arnd & Palmer,
>
> Here is the new modified compat_vdso/Makefile, please have a look,
> first. Then I would update it to v7:
> ===========================================
> # SPDX-License-Identifier: GPL-2.0-only
> #
> # Makefile for compat_vdso
> #
>
> # Symbols present in the compat_vdso
> compat_vdso-syms  = rt_sigreturn
> compat_vdso-syms += getcpu
> compat_vdso-syms += flush_icache
>
> ifdef CROSS_COMPILE_COMPAT
>         COMPAT_CC := $(CROSS_COMPILE_COMPAT)gcc
>         COMPAT_LD := $(CROSS_COMPILE_COMPAT)ld
> else
>         COMPAT_CC := $(CC)
>         COMPAT_LD := $(LD)
> endif
>
> COMPAT_CC_FLAGS := -march=rv32g -mabi=ilp32
> COMPAT_LD_FLAGS := -melf32lriscv

Have you come across a case in which a separate cross toolchain
is required? If not, I would leave this out and just set the flags for the
normal toolchain.

I also think it would be a nicer split to build the two vdso variants
as vdso64/vdso32 rather than vdso/compat_vdso. That way,
the build procedure can be kept as close as possible to the
native 32-bit build.

        Arnd