diff options
Diffstat (limited to 'LoongArch-Fix-the-condition-to-use-PC-relative-addre.patch')
| -rw-r--r-- | LoongArch-Fix-the-condition-to-use-PC-relative-addre.patch | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/LoongArch-Fix-the-condition-to-use-PC-relative-addre.patch b/LoongArch-Fix-the-condition-to-use-PC-relative-addre.patch new file mode 100644 index 0000000..f1aa4eb --- /dev/null +++ b/LoongArch-Fix-the-condition-to-use-PC-relative-addre.patch @@ -0,0 +1,179 @@ +From dba920d34797ea8e44fca1d2cfc6a08dbe9bb759 Mon Sep 17 00:00:00 2001 +From: XingLi <lixing@loongson.cn> +Date: Thu, 27 Jul 2023 09:32:21 +0800 +Subject: [PATCH 3/3] LoongArch: Fix the condition to use PC-relative + addressing in start.S + +A start.o compiled from start.S with -DPIC and no -DSHARED is used by +both crt1.o and rcrt1.o. So the LoongArch static PIE patch +unintentionally introduced PC-relative addressing for main and +__libc_start_main into crt1.o. + +While the latest Binutils (trunk, which will be released as 2.40) +supports the PC-relative relocs against an external function by creating +a PLT entry, the 2.39 release branch doesn't (and won't) support this. +An error is raised: + + "PLT stub does not represent and symbol not defined." + +So, we need the following changes: + +1. Check if ld supports the PC-relative relocs against an external + function. If it's not supported, we deem static PIE unsupported. +2. Change start.S. If static PIE is supported, use PC-relative + addressing for main and __libc_start_main and rely on the linker to + create PLT entries. Otherwise, restore the old behavior (using GOT + to address these functions). + +An alternative would be adding a new "static-pie-start.S", and some +custom logic into Makefile to build rcrt1.o with it. And, restore +start.S to the state before static PIE change so crt1.o won't contain +PC-relative relocs against external symbols. But I can't see any +benefit of this alternative, so I'd just keep it simple. + +Tested by building glibc with the following configurations: + +1. Binutils trunk + GCC trunk. Static PIE enabled. All tests + passed. +2. Binutils 2.39 branch + GCC trunk. Static PIE disabled. Tests + related to ifunc failed (it's a known issue). All other tests + passed. +3. Binutils 2.39 branch + GCC 12 branch, cross compilation with + build-many-glibcs.py from x86_64-linux-gnu. Static PIE disabled. + Build succeeded. + +From: Xi Ruoyao <xry111@xry111.site> +Date: Sun, 2 Oct 2022 22:23:09 +0800 +--- + sysdeps/loongarch/configure | 29 +++++++++++++++++++++++++---- + sysdeps/loongarch/configure.ac | 18 ++++++++++++++---- + sysdeps/loongarch/start.S | 9 +++++++-- + 3 files changed, 46 insertions(+), 10 deletions(-) + +diff --git a/sysdeps/loongarch/configure b/sysdeps/loongarch/configure +index db6341e8..4f0ac252 100644 +--- a/sysdeps/loongarch/configure ++++ b/sysdeps/loongarch/configure +@@ -11,7 +11,7 @@ if ${libc_cv_static_pie_on_loongarch+:} false; then : + $as_echo_n "(cached) " >&6 + else + +- cat > conftest.S << EOF ++ cat > conftest1.S << EOF + .global _start + .type _start, @function + _start: +@@ -27,14 +27,35 @@ x: + /* This should produce an R_LARCH_RELATIVE in the static PIE. */ + .dword _start + EOF ++ cat > conftest2.S << EOF ++.global f ++.type f, @function ++f: ++ /* The linker should be able to handle this and produce a PLT entry. */ ++ la.pcrel \$t0, \$t0, external_func ++ jirl \$zero, \$t0, 0 ++EOF ++ + libc_cv_static_pie_on_loongarch=no +- if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -static-pie -nostdlib -fPIE -o conftest conftest.S' ++ if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -static-pie -nostdlib -fPIE -o conftest1 conftest1.S' ++ { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 ++ (eval $ac_try) 2>&5 ++ ac_status=$? ++ $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5 ++ test $ac_status = 0; }; } \ ++ && { ac_try='LC_ALL=C $READELF -Wr conftest1 | grep -q R_LARCH_RELATIVE' ++ { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 ++ (eval $ac_try) 2>&5 ++ ac_status=$? ++ $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5 ++ test $ac_status = 0; }; } \ ++ && { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -shared -fPIC -o conftest2.so conftest2.S' + { { eval echo "\"\$as_me\":${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' ++ && { ac_try='LC_ALL=C $READELF -Wr conftest2.so | grep -q 'R_LARCH_JUMP_SLOT.*external_func'' + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 + (eval $ac_try) 2>&5 + ac_status=$? +@@ -43,7 +64,7 @@ EOF + then + libc_cv_static_pie_on_loongarch=yes + fi +- rm -rf conftest.* ++ 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; } +diff --git a/sysdeps/loongarch/configure.ac b/sysdeps/loongarch/configure.ac +index 603085cd..bfe4e0f2 100644 +--- a/sysdeps/loongarch/configure.ac ++++ b/sysdeps/loongarch/configure.ac +@@ -13,7 +13,7 @@ dnl satisify the requirement, but a distro may backport static PIE support into + dnl earlier GCC or Binutils releases as well. + AC_CACHE_CHECK([if the toolchain is sufficient to build static PIE on LoongArch], + libc_cv_static_pie_on_loongarch, [ +- cat > conftest.S << EOF ++ cat > conftest1.S << EOF + .global _start + .type _start, @function + _start: +@@ -28,14 +28,24 @@ x: + .word 0 + /* This should produce an R_LARCH_RELATIVE in the static PIE. */ + .dword _start ++EOF ++ cat > conftest2.S << EOF ++.global f ++.type f, @function ++f: ++ /* The linker should be able to handle this and produce a PLT entry. */ ++ la.pcrel \$t0, \$t0, external_func ++ jirl \$zero, \$t0, 0 + EOF + libc_cv_static_pie_on_loongarch=no +- if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -static-pie -nostdlib -fPIE -o conftest conftest.S]) \ +- && AC_TRY_COMMAND([LC_ALL=C $READELF -Wr conftest | grep -q R_LARCH_RELATIVE]) ++ if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -static-pie -nostdlib -fPIE -o conftest1 conftest1.S]) \ ++ && AC_TRY_COMMAND([LC_ALL=C $READELF -Wr conftest1 | grep -q R_LARCH_RELATIVE]) \ ++ && AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -shared -fPIC -o conftest2.so conftest2.S]) \ ++ && AC_TRY_COMMAND([LC_ALL=C $READELF -Wr conftest2.so | grep -q 'R_LARCH_JUMP_SLOT.*external_func']) + then + libc_cv_static_pie_on_loongarch=yes + fi +- rm -rf conftest.*]) ++ rm -rf conftest* ]) + + if test "$libc_cv_static_pie_on_loongarch" = yes; then + AC_DEFINE(SUPPORT_STATIC_PIE) +diff --git a/sysdeps/loongarch/start.S b/sysdeps/loongarch/start.S +index 1b15fc9c..87bb1d4e 100644 +--- a/sysdeps/loongarch/start.S ++++ b/sysdeps/loongarch/start.S +@@ -44,11 +44,16 @@ ENTRY (ENTRY_POINT) + cfi_undefined (1) + or a5, a0, zero /* rtld_fini */ + +-#if defined(PIC) && !defined(SHARED) ++#if ENABLE_STATIC_PIE + /* For static PIE, the GOT cannot be used in _start because the GOT entries are +- offsets instead of real addresses before __libc_start_main. */ ++ offsets instead of real addresses before __libc_start_main. ++ __libc_start_main and/or main may be not local, so we rely on the linker to ++ produce PLT entries for them. GNU ld >= 2.40 supports this. */ + # define LA la.pcrel + #else ++/* Old GNU ld (< 2.40) cannot handle PC relative address against a non-local ++ function correctly. We deem these old linkers failing to support static PIE ++ and load the addresses from GOT. */ + # define LA la.got + #endif + +-- +2.33.0 + |