Re: [PATCH v3] RISC-V: Enable static-pie.

[Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>]

On 02/01/24 07:54, yanzhang.wang@intel.com 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.
> 
> It will also check whether toolchain supports to build static-pie.

LGTM, thanks.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

> ---
>  sysdeps/riscv/configure    | 49 ++++++++++++++++++++++++++++++++++++++
>  sysdeps/riscv/configure.ac | 27 +++++++++++++++++++++
>  sysdeps/riscv/dl-machine.h |  2 +-
>  3 files changed, 77 insertions(+), 1 deletion(-)
> 
> diff --git a/sysdeps/riscv/configure b/sysdeps/riscv/configure
> index acd1f5e743..c8f01709f8 100644
> --- a/sysdeps/riscv/configure
> +++ b/sysdeps/riscv/configure
> @@ -31,3 +31,52 @@ printf "%s\n" "$libc_cv_riscv_r_align" >&6; }
>  config_vars="$config_vars
>  riscv-r-align = $libc_cv_riscv_r_align"
>  
> +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if the toolchain is sufficient to build static PIE on RISC-V" >&5
> +printf %s "checking if the toolchain is sufficient to build static PIE on RISC-V... " >&6; }
> +if test ${libc_cv_static_pie_on_riscv+y}
> +then :
> +  printf %s "(cached) " >&6
> +else $as_nop
> +
> +  cat > conftest1.S <<\EOF
> +    .globl _start
> +    .type   _start, @function
> +_start:
> +    nop
> +
> +    .data
> +    /* This should produce an R_RISCV_RELATIVE in the static PIE.  */
> +    .dword      _start
> +EOF
> +
> +  libc_cv_static_pie_on_riscv=no
> +  if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -static-pie -nostdlib -fPIE -o conftest1 conftest1.S'
> +  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
> +  (eval $ac_try) 2>&5
> +  ac_status=$?
> +  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
> +  test $ac_status = 0; }; } \
> +     && { ac_try='LC_ALL=C $READELF -Wr conftest1 | grep -q R_RISCV_RELATIVE'
> +  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
> +  (eval $ac_try) 2>&5
> +  ac_status=$?
> +  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
> +  test $ac_status = 0; }; } \
> +     && ! { ac_try='LC_ALL=C $READELF -Wl conftest1 | grep -q INTERP'
> +  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
> +  (eval $ac_try) 2>&5
> +  ac_status=$?
> +  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
> +  test $ac_status = 0; }; }
> +  then
> +    libc_cv_static_pie_on_riscv=yes
> +  fi
> +  rm -rf conftest*
> +fi
> +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_static_pie_on_riscv" >&5
> +printf "%s\n" "$libc_cv_static_pie_on_riscv" >&6; }
> +
> +if test "$libc_cv_static_pie_on_riscv" = yes; then
> +  printf "%s\n" "#define SUPPORT_STATIC_PIE 1" >>confdefs.h
> +
> +fi
> diff --git a/sysdeps/riscv/configure.ac b/sysdeps/riscv/configure.ac
> index dbcc216689..ee3d1ed014 100644
> --- a/sysdeps/riscv/configure.ac
> +++ b/sysdeps/riscv/configure.ac
> @@ -16,3 +16,30 @@ EOF
>    fi
>    rm -rf conftest.*])
>  LIBC_CONFIG_VAR([riscv-r-align], [$libc_cv_riscv_r_align])
> +
> +dnl Test if the toolchain is new enough for static PIE.
> +AC_CACHE_CHECK([if the toolchain is sufficient to build static PIE on RISC-V],
> +libc_cv_static_pie_on_riscv, [
> +  cat > conftest1.S <<\EOF
> +    .globl _start
> +    .type   _start, @function
> +_start:
> +    nop
> +
> +    .data
> +    /* This should produce an R_RISCV_RELATIVE in the static PIE.  */
> +    .dword      _start
> +EOF
> +
> +  libc_cv_static_pie_on_riscv=no
> +  if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -static-pie -nostdlib -fPIE -o conftest1 conftest1.S]) \
> +     && AC_TRY_COMMAND([LC_ALL=C $READELF -Wr conftest1 | grep -q R_RISCV_RELATIVE]) \
> +     && ! AC_TRY_COMMAND([LC_ALL=C $READELF -Wl conftest1 | grep -q INTERP])
> +  then
> +    libc_cv_static_pie_on_riscv=yes
> +  fi
> +  rm -rf conftest* ])
> +
> +if test "$libc_cv_static_pie_on_riscv" = yes; then
> +  AC_DEFINE(SUPPORT_STATIC_PIE)
> +fi
> diff --git a/sysdeps/riscv/dl-machine.h b/sysdeps/riscv/dl-machine.h
> index ffb8c4aaa0..0cbb476c05 100644
> --- a/sysdeps/riscv/dl-machine.h
> +++ b/sysdeps/riscv/dl-machine.h
> @@ -348,7 +348,7 @@ 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