Re: [PATCH] RISC-V: Enable static-pie.

[Palmer Dabbelt <palmer@dabbelt.com>]

On Thu, 10 Aug 2023 16:33:48 PDT (-0700), libc-alpha@sourceware.org wrote:
> From: Yanzhang Wang <yanzhang.wang@intel.com>
>
> This patch referents the commit 374cef3 to add static-pie support. And
> because the dummy link map is used when relocating ourselves, so need
> not to set __global_pointer$ at this time.

Do you have test results?  IIRC the only reason we didn't enable this 
when submitting the original port was because we didn't have time to 
test it.  If it's passing a reasonable amount of the tests it's fine 
with me, but we need to at least look because there could be lurking 
issues.

> ---
>  sysdeps/riscv/configure    | 2 ++
>  sysdeps/riscv/configure.ac | 3 +++
>  sysdeps/riscv/dl-machine.h | 2 +-
>  3 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/sysdeps/riscv/configure b/sysdeps/riscv/configure
> index 2372225a26..340163779f 100644
> --- a/sysdeps/riscv/configure
> +++ b/sysdeps/riscv/configure
> @@ -29,3 +29,5 @@ fi
>  $as_echo "$libc_cv_riscv_r_align" >&6; }
>  config_vars="$config_vars
>  riscv-r-align = $libc_cv_riscv_r_align"
> +
> +$as_echo "#define SUPPORT_STATIC_PIE 1" >>confdefs.h
> diff --git a/sysdeps/riscv/configure.ac b/sysdeps/riscv/configure.ac
> index dbcc216689..36da2b5396 100644
> --- a/sysdeps/riscv/configure.ac
> +++ b/sysdeps/riscv/configure.ac
> @@ -16,3 +16,6 @@ EOF
>    fi
>    rm -rf conftest.*])
>  LIBC_CONFIG_VAR([riscv-r-align], [$libc_cv_riscv_r_align])
> +
> +dnl Static PIE is supported.
> +AC_DEFINE(SUPPORT_STATIC_PIE)
> diff --git a/sysdeps/riscv/dl-machine.h b/sysdeps/riscv/dl-machine.h
> index c0c9bd93ad..ad875c0828 100644
> --- a/sysdeps/riscv/dl-machine.h
> +++ b/sysdeps/riscv/dl-machine.h
> @@ -323,7 +323,7 @@ elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
>        gotplt[1] = (ElfW(Addr)) l;
>      }
>
> -  if (l->l_type == lt_executable)
> +  if (l->l_type == lt_executable && l->l_scope != NULL)
>      {
>        /* The __global_pointer$ may not be defined by the linker if the
>  	 $gp register does not be used to access the global variable