On Thu, 5 Jul 2018 at 10:37, Thomas Petazzoni thomas.petazzoni@bootlin.com wrote:
Hello Christophe,
On Wed, 4 Jul 2018 17:55:19 +0200, Christophe Lyon wrote:
Implement _start: compute parameters for __self_reloc, and give control to the user program.
* ldso/ldso/arm/dl-startup.h: Implement _start for __FDPIC__.Signed-off-by: Mickaël Guêné mickael.guene@st.com Signed-off-by: Christophe Lyon christophe.lyon@st.com
This is very likely me not doing things correctly, but this change doesn't build, because it uses ARM instructions on Thumb2-only systems. I'm trying to build a Cortex-M4 FDPIC toolchain with your patches. My gcc has the following details (it is gcc 8.1.0 on top of which I have backported your ARM FDPIC patches):
/home/test/outputs/arm-fdpic/host/bin/arm-buildroot-uclinuxfdpiceabi-gcc -v Using built-in specs. COLLECT_GCC=/home/test/outputs/arm-fdpic/host/bin/arm-buildroot-uclinuxfdpiceabi-gcc.br_real COLLECT_LTO_WRAPPER=/home/test/outputs/arm-fdpic/host/libexec/gcc/arm-buildroot-uclinuxfdpiceabi/8.1.0/lto-wrapper Target: arm-buildroot-uclinuxfdpiceabi Configured with: ./configure --prefix=/home/test/outputs/arm-fdpic/host --sysconfdir=/home/test/outputs/arm-fdpic/host/etc --localstatedir=/home/test/outputs/arm-fdpic/host/var --enable-shared --disable-static --disable-gtk-doc --disable-gtk-doc-html --disable-doc --disable-docs --disable-documentation --disable-debug --with-xmlto=no --with-fop=no --disable-dependency-tracking --target=arm-buildroot-uclinuxfdpiceabi --with-sysroot=/home/test/outputs/arm-fdpic/host/arm-buildroot-uclinuxfdpiceabi/sysroot --disable-__cxa_atexit --with-gnu-ld --disable-libssp --disable-multilib --with-gmp=/home/test/outputs/arm-fdpic/host --with-mpc=/home/test/outputs/arm-fdpic/host --with-mpfr=/home/test/outputs/arm-fdpic/host --with-pkgversion='Buildroot 2018.08-git-00602-g3ecd583' --with-bugurl=http://bugs.buildroot.net/ --disable-libquadmath --disable-libsanitizer --disable-tls --disable-libmudflap --enable-threads --without-isl --without-cloog --with-float=soft --disable-decimal-float --with-abi=aapcs-linux --with-cpu=cortex-m4 --with-float=soft --with-mode=thumb --enable-languages=c --disable-shared --without-headers --disable-threads --with-newlib --disable-largefile --disable-nls Thread model: single gcc version 8.1.0 (Buildroot 2018.08-git-00602-g3ecd583)
I.e, it generates code for Cortex-M4, soft-float, Thumb by default.
The dl-startup code fails to build with:
/home/test/outputs/arm-fdpic/host/bin/arm-buildroot-uclinuxfdpiceabi-gcc -c ldso/ldso/ldso.c -o ldso/ldso/ldso.oS -Wall -Wstrict-prototypes -Wstrict-aliasing -Wno-nonnull-compare -funsigned-char -fno-builtin -fno-asm -fmerge-all-constants -msoft-float -st d=gnu99 -mlittle-endian -fno-stack-protector -nostdinc -I./include -I./include -include libc-symbols.h -I./libc/sysdeps/linux/arm -I./libc/sysdeps/linux -I./ldso/ldso/arm -I./ldso/include -I. -Os -fstrict-aliasing -I./libpthread/linuxthreads/sysdeps/unix/ sysv/linux/arm -I./libpthread/linuxthreads/sysdeps/arm -I./libpthread/linuxthreads/sysdeps/unix/sysv/linux -I./libpthread/linuxthreads/sysdeps/pthread -I./libpthread/linuxthreads -I./libpthread -I./libc/sysdeps/linux/common -isystem /home/test/outputs/arm -fdpic/host/lib/gcc/arm-buildroot-uclinuxfdpiceabi/8.1.0/include-fixed -isystem /home/test/outputs/arm-fdpic/host/lib/gcc/arm-buildroot-uclinuxfdpiceabi/8.1.0/include -I/home/test/outputs/arm-fdpic/build/linux-headers-4.17.4/usr/include/ -DNDEBUG -DNOT_IN _libc -DIS_IN_rtld -fno-stack-protector -fno-omit-frame-pointer -fno-unwind-tables -fno-asynchronous-unwind-tables -I./ldso/ldso/arm -I./ldso/include -I./ldso/ldso -DUCLIBC_RUNTIME_PREFIX="/" -DUCLIBC_LDSO="ld-uClibc.so.1" -DIN_LIB=rtld -mfdpic -DSHAR ED -DLDSO_ELFINTERP="arm/elfinterp.c" -DLDSO_MULTILIB_DIR="lib/" -MT ldso/ldso/ldso.oS -MD -MP -MF ldso/ldso/.ldso.oS.dep In file included from ./include/bits/waitstatus.h:72, from ./include/stdlib.h:44, from ./ldso/include/ldso.h:33, from ldso/ldso/ldso.c:32: ./ldso/include/dl-syscall.h: In function '_dl_pread': ./ldso/include/dl-syscall.h:169:69: warning: right shift count >= width of type [-Wshift-count-overflow] return __syscall_pread(fd, buf, count, 0, __LONG_LONG_PAIR((offset >> 32), (offset & 0xffffffff))); ^~ ./include/endian.h:52:39: note: in definition of macro '__LONG_LONG_PAIR' # define __LONG_LONG_PAIR(HI, LO) LO, HI ^~ In file included from ./ldso/ldso/arm/dl-inlines.h:1, from ./ldso/include/ldso.h:183, from ldso/ldso/ldso.c:32: ./ldso/ldso/arm/../fdpic/dl-inlines.h: In function '_dl_funcdesc_for': ./ldso/ldso/arm/../fdpic/dl-inlines.h:180:8: warning: assignment to 'struct funcdesc_value **' from incompatible pointer type 'void **' [-Wincompatible-pointer-types] entry = htab_find_slot(ht, entry_point, 1, hash_pointer, eq_pointer); ^ In file included from ldso/ldso/ldso.c:45: ldso/ldso/arm/elfinterp.c: In function '_dl_linux_resolver': ldso/ldso/arm/elfinterp.c:95:9: warning: returning 'volatile struct funcdesc_value *' from a function with return type 'long unsigned int' makes integer from pointer without a cast [-Wint-conversion] return got_entry; ^~~~~~~~~ ldso/ldso/arm/elfinterp.c: In function '_dl_do_reloc': ldso/ldso/arm/elfinterp.c:364:65: warning: passing argument 1 of '_dl_funcdesc_for' makes pointer from integer without a cast [-Wint-conversion] reloc_value = (unsigned long) _dl_funcdesc_for(symbol_addr + reloc_value, sym_ref.tpnt->loadaddr.got_value); ~~~~~~~~~~~~^~~~~~~~~~~~~ In file included from ./ldso/ldso/arm/dl-inlines.h:1, from ./ldso/include/ldso.h:183, from ldso/ldso/ldso.c:32: ./ldso/ldso/arm/../fdpic/dl-inlines.h:165:25: note: expected 'void *' but argument is of type 'long unsigned int' _dl_funcdesc_for (void *entry_point, void *got_value) ~~~~~~^~~~~~~~~~~ In file included from ldso/ldso/ldso.c:45: ldso/ldso/arm/elfinterp.c: In function '_dl_do_lazy_reloc': ldso/ldso/arm/elfinterp.c:429:23: warning: assignment to 'void *' from 'unsigned int' makes pointer from integer without a cast [-Wint-conversion] dst->entry_point = DL_RELOC_ADDR(tpnt->loadaddr, dst->entry_point); ^ In file included from ldso/ldso/ldso.c:86: ldso/ldso/dl-startup.c: In function '_dl_start': ldso/ldso/dl-startup.c:313:13: warning: variable 'strtab' set but not used [-Wunused-but-set-variable] char *strtab; ^~~~~~ ldso/ldso/dl-startup.c:125:13: warning: variable 'got' set but not used [-Wunused-but-set-variable] ElfW(Addr) got; ^~~ In file included from ./ldso/ldso/arm/dl-sysdep.h:135, from ./ldso/include/dl-defs.h:77, from ./ldso/include/dl-string.h:15, from ./ldso/include/ldso.h:53, ...skipping... In file included from ./ldso/ldso/arm/dl-inlines.h:1, from ./ldso/include/ldso.h:183, from ldso/ldso/ldso.c:32: ./ldso/ldso/arm/../fdpic/dl-inlines.h:165:25: note: expected 'void *' but argument is of type 'long unsigned int' _dl_funcdesc_for (void *entry_point, void *got_value) ~~~~~~^~~~~~~~~~~ In file included from ldso/ldso/ldso.c:45: ldso/ldso/arm/elfinterp.c: In function '_dl_do_lazy_reloc': ldso/ldso/arm/elfinterp.c:429:23: warning: assignment to 'void *' from 'unsigned int' makes pointer from integer without a cast [-Wint-conversion] dst->entry_point = DL_RELOC_ADDR(tpnt->loadaddr, dst->entry_point); ^ In file included from ldso/ldso/ldso.c:86: ldso/ldso/dl-startup.c: In function '_dl_start': ldso/ldso/dl-startup.c:313:13: warning: variable 'strtab' set but not used [-Wunused-but-set-variable] char *strtab; ^~~~~~ ldso/ldso/dl-startup.c:125:13: warning: variable 'got' set but not used [-Wunused-but-set-variable] ElfW(Addr) got; ^~~ In file included from ./ldso/ldso/arm/dl-sysdep.h:135, from ./ldso/include/dl-defs.h:77, from ./ldso/include/dl-string.h:15, from ./ldso/include/ldso.h:53, from ldso/ldso/ldso.c:32: ldso/ldso/dl-hash.c: In function '_dl_find_hash': ./ldso/ldso/arm/../fdpic/dl-sysdep.h:111:4: warning: pointer/integer type mismatch in conditional expression : DL_RELOC_ADDR ((TPNT)->loadaddr, (SYM)->st_value)) ^ ldso/ldso/dl-hash.c:384:20: note: in expansion of macro 'DL_FIND_HASH_VALUE' return (char *)DL_FIND_HASH_VALUE(tpnt, type_class, sym); ^~~~~~~~~~~~~~~~~~ /tmp/cceTVltl.s: Assembler messages: /tmp/cceTVltl.s:14: Error: selected processor does not support ARM opcodes /tmp/cceTVltl.s:19: Error: attempt to use an ARM instruction on a Thumb-only processor -- `sub r4,pc,#8' /tmp/cceTVltl.s:20: Error: attempt to use an ARM instruction on a Thumb-only processor -- `ldr r1,.L__ROFIXUP_LIST__' /tmp/cceTVltl.s:21: Error: attempt to use an ARM instruction on a Thumb-only processor -- `add r1,r1,r4' /tmp/cceTVltl.s:22: Error: attempt to use an ARM instruction on a Thumb-only processor -- `ldr r2,.L__ROFIXUP_END__' /tmp/cceTVltl.s:23: Error: attempt to use an ARM instruction on a Thumb-only processor -- `add r2,r2,r4' /tmp/cceTVltl.s:24: Error: attempt to use an ARM instruction on a Thumb-only processor -- `movs r0,r8' /tmp/cceTVltl.s:25: Error: attempt to use an ARM instruction on a Thumb-only processor -- `moveq r0,r7' /tmp/cceTVltl.s:26: Error: attempt to use an ARM instruction on a Thumb-only processor -- `push {r7,r8,r9,r10}' /tmp/cceTVltl.s:27: Error: attempt to use an ARM instruction on a Thumb-only processor -- `bl __self_reloc' /tmp/cceTVltl.s:28: Error: attempt to use an ARM instruction on a Thumb-only processor -- `pop {r7,r8,r9,r10}' /tmp/cceTVltl.s:29: Error: attempt to use an ARM instruction on a Thumb-only processor -- `mov r1,r7' /tmp/cceTVltl.s:30: Error: attempt to use an ARM instruction on a Thumb-only processor -- `mov r2,r8' /tmp/cceTVltl.s:31: Error: attempt to use an ARM instruction on a Thumb-only processor -- `mov r3,r9' /tmp/cceTVltl.s:32: Error: attempt to use an ARM instruction on a Thumb-only processor -- `mov r4,sp' /tmp/cceTVltl.s:33: Error: attempt to use an ARM instruction on a Thumb-only processor -- `sub r5,sp,#8' /tmp/cceTVltl.s:34: Error: attempt to use an ARM instruction on a Thumb-only processor -- `sub sp,sp,#16' /tmp/cceTVltl.s:35: Error: attempt to use an ARM instruction on a Thumb-only processor -- `str r4,[sp,#4]' /tmp/cceTVltl.s:36: Error: attempt to use an ARM instruction on a Thumb-only processor -- `str r5,[sp,#0]' /tmp/cceTVltl.s:37: Error: attempt to use an ARM instruction on a Thumb-only processor -- `mov r9,r0' /tmp/cceTVltl.s:38: Error: attempt to use an ARM instruction on a Thumb-only processor -- `mov r4,r9' /tmp/cceTVltl.s:39: Error: attempt to use an ARM instruction on a Thumb-only processor -- `bl _dl_start' /tmp/cceTVltl.s:40: Error: attempt to use an ARM instruction on a Thumb-only processor -- `ldr r10,.L_dl_fini_gotofffuncdesc' /tmp/cceTVltl.s:41: Error: attempt to use an ARM instruction on a Thumb-only processor -- `add r10,r10,r4' /tmp/cceTVltl.s:42: Error: attempt to use an ARM instruction on a Thumb-only processor -- `ldr r5,[sp,#8]' /tmp/cceTVltl.s:43: Error: attempt to use an ARM instruction on a Thumb-only processor -- `ldr r9,[sp,#12]' /tmp/cceTVltl.s:44: Error: attempt to use an ARM instruction on a Thumb-only processor -- `add sp,sp,#16' /tmp/cceTVltl.s:45: Error: attempt to use an ARM instruction on a Thumb-only processor -- `bx r5' /tmp/cceTVltl.s:47: Error: attempt to use an ARM instruction on a Thumb-only processor -- `b .loopforever' make[2]: *** [ldso/ldso/ldso.oS] Error 1 make[1]: *** [/home/test/outputs/arm-fdpic/build/uclibc-1.0.30/.stamp_built] Error 2 make: *** [_all] Error 2
Any idea ?
Thanks for checking that. I did build with a GCC defaulting to Thumb mode, but it still uses a CPU that supports ARM mode, so I missed these problems.
Best regards,
Thomas Petazzoni
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com