* Re: [PATCH v2 1/1] LoongArch: Add static PIE support
2022-09-23 11:16 ` [PATCH v2 1/1] " Xi Ruoyao
@ 2022-09-23 13:23 ` Adhemerval Zanella Netto
2022-09-23 15:24 ` Xi Ruoyao
2022-09-24 1:18 ` liuzhensong
1 sibling, 1 reply; 5+ messages in thread
From: Adhemerval Zanella Netto @ 2022-09-23 13:23 UTC (permalink / raw)
To: Xi Ruoyao, libc-alpha
Cc: caiyinyu, Chenghua Xu, liuzhensong, Lulu Cheng, Wang Xuerui
On 23/09/22 08:16, Xi Ruoyao via Libc-alpha wrote:
> If the compiler is new enough, enable static PIE support. In the static
> PIE version of _start (in rcrt1.o), use la.pcrel instead of la.got
> because in a static PIE we cannot use GOT entries until the dynamic
> relocations for GOT are resolved.
The patch looks ok and with a recent GCC I see both SUPPORT_STATIC_PIE
and ENABLE_STATIC_PIE being set.
$ loongarch64-glibc-linux-gnu-gcc -v 2>&1 | tail -n1
gcc version 13.0.0 20220923 (experimental) [releases/gcc-12 r12-8552-g65941a91091] (GCC)
$ loongarch64-glibc-linux-gnu-ld -v
GNU ld (GNU Binutils) 2.39.0.20220923
However I can't actually build glibc:
make[2]: Entering directory '/home/azanella/Projects/glibc/glibc-git/support'
/home/azanella/toolchain/install/compilers//loongarch64-linux-gnu-lp64d/bin/loongarch64-glibc-linux-gnu-gcc -o /home/azanella/Projects/glibc/build/loongarch64-linux-gnu-lp64d/support/test-run-command -nostdlib -nostartfiles -static -static-pie /home/azanella/Projects/glibc/build/loongarch64-linux-gnu-lp64d/csu/rcrt1.o /home/azanella/Projects/glibc/build/loongarch64-linux-gnu-lp64d/csu/crti.o `/home/azanella/toolchain/install/compilers//loongarch64-linux-gnu-lp64d/bin/loongarch64-glibc-linux-gnu-gcc --print-file-name=crtbeginS.o` /home/azanella/Projects/glibc/build/loongarch64-linux-gnu-lp64d/support/test-run-command.o /home/azanella/Projects/glibc/build/loongarch64-linux-gnu-lp64d/elf/static-stubs.o /home/azanella/Projects/glibc/build/loongarch64-linux-gnu-lp64d/support/libsupport_nonshared.a -Wl,-z,now -Wl,--start-group /home/azanella/Projects/glibc/build/loongarch64-linux-gnu-lp64d/libc.a -lgcc -Wl,--end-group `/home/azanella/toolchain/install/compilers//loongarch64-linux-gnu-lp64d/bin/loongarch64-glibc-linux-gnu-gcc --print-file-name=crtendS.o` /home/azanella/Projects/glibc/build/loongarch64-linux-gnu-lp64d/csu/crtn.o
/home/azanella/Projects/glibc/build/loongarch64-linux-gnu-lp64d/libc.a(setlocale.o)(__libc_freeres_fn+0x144): error: R_LARCH_SOP_PUSH_TLS_GOT against [undefweak] `_nl_current_LC_COLLATE':
Internal: Shouldn't be resolved to const.
Using --disable-default-pie avoids this build issue.
> ---
> sysdeps/loongarch/configure | 37 ++++++++++++++++++++++++++++++++++
> sysdeps/loongarch/configure.ac | 20 ++++++++++++++++++
> sysdeps/loongarch/start.S | 14 ++++++++++---
> 3 files changed, 68 insertions(+), 3 deletions(-)
>
> diff --git a/sysdeps/loongarch/configure b/sysdeps/loongarch/configure
> index 43b54d4965..4c1dd303bf 100644
> --- a/sysdeps/loongarch/configure
> +++ b/sysdeps/loongarch/configure
> @@ -3,3 +3,40 @@
>
> $as_echo "#define HIDDEN_VAR_NEEDS_DYNAMIC_RELOC 1" >>confdefs.h
>
> +
> +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if the compiler is sufficient to build static PIE on LoongArch" >&5
> +$as_echo_n "checking if the compiler is sufficient to build static PIE on LoongArch... " >&6; }
> +if ${libc_cv_static_pie_on_loongarch+:} false; then :
> + $as_echo_n "(cached) " >&6
> +else
> +
> + cat > conftest.c << EOF
> +extern int x __asm__("y");
> +int y;
> +void *_start() { return &x; }
> +EOF
> + libc_cv_static_pie_on_loongarch=no
> + if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -static-pie -nostdlib -fPIE -o conftest conftest.c'
> + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
> + (eval $ac_try) 2>&5
> + ac_status=$?
> + $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
> + test $ac_status = 0; }; } \
> + && { ac_try='LC_ALL=C $READELF -Wr conftest | grep -q R_LARCH_RELATIVE'
> + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
> + (eval $ac_try) 2>&5
> + ac_status=$?
> + $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
> + test $ac_status = 0; }; }
> + then
> + libc_cv_static_pie_on_loongarch=yes
> + fi
> + rm -rf conftest.*
> +fi
> +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_static_pie_on_loongarch" >&5
> +$as_echo "$libc_cv_static_pie_on_loongarch" >&6; }
> +
> +if test "$libc_cv_static_pie_on_loongarch" = yes; then
> + $as_echo "#define SUPPORT_STATIC_PIE 1" >>confdefs.h
> +
> +fi
> diff --git a/sysdeps/loongarch/configure.ac b/sysdeps/loongarch/configure.ac
> index f744367bf3..f389679459 100644
> --- a/sysdeps/loongarch/configure.ac
> +++ b/sysdeps/loongarch/configure.ac
> @@ -4,3 +4,23 @@ GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory.
> dnl It is always possible to access static and hidden symbols in an
> dnl position independent way.
> AC_DEFINE(HIDDEN_VAR_NEEDS_DYNAMIC_RELOC)
> +
> +dnl test if GCC is new enough for static PIE.
> +AC_CACHE_CHECK([if the compiler is sufficient to build static PIE on LoongArch],
> +libc_cv_static_pie_on_loongarch, [
> + cat > conftest.c << EOF
> +extern int x __asm__("y");
> +int y;
> +void *_start() { return &x; }
> +EOF
> + libc_cv_static_pie_on_loongarch=no
> + if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -static-pie -nostdlib -fPIE -o conftest conftest.c]) \
> + && AC_TRY_COMMAND([LC_ALL=C $READELF -Wr conftest | grep -q R_LARCH_RELATIVE])
> + then
> + libc_cv_static_pie_on_loongarch=yes
> + fi
> + rm -rf conftest.*])
> +
> +if test "$libc_cv_static_pie_on_loongarch" = yes; then
> + AC_DEFINE(SUPPORT_STATIC_PIE)
> +fi
> diff --git a/sysdeps/loongarch/start.S b/sysdeps/loongarch/start.S
> index e66af16d57..05cabd9b96 100644
> --- a/sysdeps/loongarch/start.S
> +++ b/sysdeps/loongarch/start.S
> @@ -60,9 +60,17 @@ ENTRY (ENTRY_POINT)
> cfi_undefined (1)
> or a5, a0, zero /* rtld_fini */
>
> +#if defined(PIC) && !defined(SHARED)
> +/* For static PIE, the GOT cannot be used in _start because the GOT entries are
> + offsets instead of real addresses before __libc_start_main. */
> +# define LA la.pcrel
> +#else
> /* We must get symbol main through GOT table, since main may not be local.
> For instance: googletest defines main in dynamic library. */
> - la.got a0, t0, main
> +# define LA la.got
> +#endif
> +
> + LA a0, t0, main
> REG_L a1, sp, 0
> ADDI a2, sp, SZREG
>
> @@ -73,9 +81,9 @@ ENTRY (ENTRY_POINT)
> move a4, zero /* used to be fini */
> or a6, sp, zero /* stack_end */
>
> - la.got ra, t0, __libc_start_main
> + LA ra, t0, __libc_start_main
> jirl ra, ra, 0
>
> - la.got ra, t0, abort
> + LA ra, t0, abort
> jirl ra, ra, 0
> END (ENTRY_POINT)
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 1/1] LoongArch: Add static PIE support
2022-09-23 11:16 ` [PATCH v2 1/1] " Xi Ruoyao
2022-09-23 13:23 ` Adhemerval Zanella Netto
@ 2022-09-24 1:18 ` liuzhensong
1 sibling, 0 replies; 5+ messages in thread
From: liuzhensong @ 2022-09-24 1:18 UTC (permalink / raw)
To: Xi Ruoyao, libc-alpha; +Cc: caiyinyu, Lulu Cheng, Wang Xuerui, Chenghua Xu
[-- Attachment #1: Type: text/plain, Size: 4579 bytes --]
在 2022/9/23 下午7:16, Xi Ruoyao 写道:
> If the compiler is new enough, enable static PIE support. In the static
> PIE version of _start (in rcrt1.o), use la.pcrel instead of la.got
> because in a static PIE we cannot use GOT entries until the dynamic
> relocations for GOT are resolved.
> ---
> sysdeps/loongarch/configure | 37 ++++++++++++++++++++++++++++++++++
> sysdeps/loongarch/configure.ac | 20 ++++++++++++++++++
> sysdeps/loongarch/start.S | 14 ++++++++++---
> 3 files changed, 68 insertions(+), 3 deletions(-)
>
> diff --git a/sysdeps/loongarch/configure b/sysdeps/loongarch/configure
> index 43b54d4965..4c1dd303bf 100644
> --- a/sysdeps/loongarch/configure
> +++ b/sysdeps/loongarch/configure
> @@ -3,3 +3,40 @@
>
> $as_echo "#define HIDDEN_VAR_NEEDS_DYNAMIC_RELOC 1" >>confdefs.h
>
> +
> +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if the compiler is sufficient to build static PIE on LoongArch" >&5
> +$as_echo_n "checking if the compiler is sufficient to build static PIE on LoongArch... " >&6; }
> +if ${libc_cv_static_pie_on_loongarch+:} false; then :
> + $as_echo_n "(cached) " >&6
> +else
> +
> + cat > conftest.c << EOF
> +extern int x __asm__("y");
> +int y;
> +void *_start() { return &x; }
> +EOF
> + libc_cv_static_pie_on_loongarch=no
> + if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -static-pie -nostdlib -fPIE -o conftest conftest.c'
> + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
> + (eval $ac_try) 2>&5
> + ac_status=$?
> + $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
> + test $ac_status = 0; }; } \
> + && { ac_try='LC_ALL=C $READELF -Wr conftest | grep -q R_LARCH_RELATIVE'
> + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
> + (eval $ac_try) 2>&5
> + ac_status=$?
> + $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
> + test $ac_status = 0; }; }
> + then
> + libc_cv_static_pie_on_loongarch=yes
> + fi
> + rm -rf conftest.*
> +fi
> +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_static_pie_on_loongarch" >&5
> +$as_echo "$libc_cv_static_pie_on_loongarch" >&6; }
> +
> +if test "$libc_cv_static_pie_on_loongarch" = yes; then
> + $as_echo "#define SUPPORT_STATIC_PIE 1" >>confdefs.h
> +
> +fi
> diff --git a/sysdeps/loongarch/configure.ac b/sysdeps/loongarch/configure.ac
> index f744367bf3..f389679459 100644
> --- a/sysdeps/loongarch/configure.ac
> +++ b/sysdeps/loongarch/configure.ac
> @@ -4,3 +4,23 @@ GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory.
> dnl It is always possible to access static and hidden symbols in an
> dnl position independent way.
> AC_DEFINE(HIDDEN_VAR_NEEDS_DYNAMIC_RELOC)
> +
> +dnl test if GCC is new enough for static PIE.
> +AC_CACHE_CHECK([if the compiler is sufficient to build static PIE on LoongArch],
> +libc_cv_static_pie_on_loongarch, [
> + cat > conftest.c << EOF
> +extern int x __asm__("y");
> +int y;
> +void *_start() { return &x; }
> +EOF
> + libc_cv_static_pie_on_loongarch=no
> + if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -static-pie -nostdlib -fPIE -o conftest conftest.c]) \
> + && AC_TRY_COMMAND([LC_ALL=C $READELF -Wr conftest | grep -q R_LARCH_RELATIVE])
> + then
> + libc_cv_static_pie_on_loongarch=yes
> + fi
> + rm -rf conftest.*])
> +
> +if test "$libc_cv_static_pie_on_loongarch" = yes; then
> + AC_DEFINE(SUPPORT_STATIC_PIE)
> +fi
> diff --git a/sysdeps/loongarch/start.S b/sysdeps/loongarch/start.S
> index e66af16d57..05cabd9b96 100644
> --- a/sysdeps/loongarch/start.S
> +++ b/sysdeps/loongarch/start.S
> @@ -60,9 +60,17 @@ ENTRY (ENTRY_POINT)
> cfi_undefined (1)
> or a5, a0, zero /* rtld_fini */
>
> +#if defined(PIC) && !defined(SHARED)
> +/* For static PIE, the GOT cannot be used in _start because the GOT entries are
> + offsets instead of real addresses before __libc_start_main. */
> +# define LA la.pcrel
> +#else
> /* We must get symbol main through GOT table, since main may not be local.
> For instance: googletest defines main in dynamic library. */
> - la.got a0, t0, main
> +# define LA la.got
> +#endif
It takes some time to evaluate the macro of 'LA'.
> +
> + LA a0, t0, main
> REG_L a1, sp, 0
> ADDI a2, sp, SZREG
>
> @@ -73,9 +81,9 @@ ENTRY (ENTRY_POINT)
> move a4, zero /* used to be fini */
> or a6, sp, zero /* stack_end */
>
> - la.got ra, t0, __libc_start_main
> + LA ra, t0, __libc_start_main
> jirl ra, ra, 0
>
> - la.got ra, t0, abort
> + LA ra, t0, abort
> jirl ra, ra, 0
> END (ENTRY_POINT)
^ permalink raw reply [flat|nested] 5+ messages in thread