Message ID | e1aafaed-c810-eac2-35f0-8489b4c24d05@linux.vnet.ibm.com |
---|---|
State | New |
Headers | show |
On 06/08/2017 02:02 PM, Stefan Liebler wrote: > Question about glibc configure flag --disable-hidden-plt: > Is this option supported or is it used by somebody? > It defines NO_HIDDEN which influences the definition of HIDDEN_JUMPTARGET. > I've tried to build glibc with this configure flag on s390, but it fails > due to several reasons. I think we can remove --disable-hidden-plt. It is broken on x86-64 as well, and I think the whole thing stopped working with PLT avoidance for hidden symbols in binutils and switching to namespace-clean names (which are generally hidden). Thanks, Florian
On Fri, 9 Jun 2017, Florian Weimer wrote: > On 06/08/2017 02:02 PM, Stefan Liebler wrote: > > Question about glibc configure flag --disable-hidden-plt: > > Is this option supported or is it used by somebody? > > It defines NO_HIDDEN which influences the definition of HIDDEN_JUMPTARGET. > > I've tried to build glibc with this configure flag on s390, but it fails > > due to several reasons. > > I think we can remove --disable-hidden-plt. It is broken on x86-64 as > well, and I think the whole thing stopped working with PLT avoidance for > hidden symbols in binutils and switching to namespace-clean names (which > are generally hidden). Do note however the unconditional definition of NO_HIDDEN in sysdeps/mach/hurd/configure.ac (and the corresponding comment pointing to a discussion of that). We really need Hurd people to get current glibc working on Hurd without external patches and contribute build-many-glibcs.py support for it so it's possible to make sure changes don't break Hurd.
On Jun 08 2017, Stefan Liebler <stli@linux.vnet.ibm.com> wrote: > [BZ #21537] > * sysdeps/s390/s390-32/sysdep.h (JUMPTARGET, SYSCALL_PIC_SETUP): > Check SHARED instead of PIC. > (SYSCALL_PIC_SETUP): Add missing semicolons. > * sysdeps/s390/s390-64/sysdep.h (JUMPTARGET, SYSCALL_PIC_SETUP): > Check SHARED instead of PIC. > * sysdeps/unix/sysv/linux/s390/s390-32/__makecontext_ret.S > (__makecontext_ret): Adjust code to jump to exit. Ok. Andreas.
On 06/12/2017 02:05 PM, Andreas Schwab wrote: > On Jun 08 2017, Stefan Liebler <stli@linux.vnet.ibm.com> wrote: > >> [BZ #21537] >> * sysdeps/s390/s390-32/sysdep.h (JUMPTARGET, SYSCALL_PIC_SETUP): >> Check SHARED instead of PIC. >> (SYSCALL_PIC_SETUP): Add missing semicolons. >> * sysdeps/s390/s390-64/sysdep.h (JUMPTARGET, SYSCALL_PIC_SETUP): >> Check SHARED instead of PIC. >> * sysdeps/unix/sysv/linux/s390/s390-32/__makecontext_ret.S >> (__makecontext_ret): Adjust code to jump to exit. > > Ok. > > Andreas. > Committed. Thanks. Stefan
commit a1d6669382f30e16edf787adfa87b6f77a309357 Author: Stefan Liebler <stli@linux.vnet.ibm.com> Date: Thu Jun 8 13:13:27 2017 +0200 S390: Fix build with gcc configured with --enable-default-pie. [BZ #21537] Building glibc with gcc configured with --enable-default-pie failed on s390 due to assembler messages: ../sysdeps/unix/sysv/linux/s390/s390-32/__makecontext_ret.S:44: Error: junk at end of line, first unrecognized character is `@' HIDDEN_JUMPTARGET was expanded to exit@PLT@GOTOFF. If SHARED is not defined, HIDDEN_JUMPTARGET is defined to JUMPTARGET in sysdeps/s390/s390-32/sysdep.h. There it expanded to exit@PLT in non SHARED case as PIC is defined if gcc is configured with --enable-default-pie. Thus I've changed the "ifdef PIC" to "ifdef SHARED" as we do not want PLTs in the static obj files. I've also changed this in sysdeps/s390/s390-64/sysdep.h. I've also adjusted sysdeps/unix/sysv/linux/s390/s390-32/__makecontext_ret.S. If glibc is configured with --disable-hidden-plt, then NO_HIDDEN is defined. In SHARED case HIDDEN_JUMPTARGET would be expanded to exit@PLT@GOTOFF instead of __GI_exit@GOTOFF. Now we jump to: - __GI_exit if SHARED is defined - exit@PLT if SHARED and NO_HIDDEN is defined - exit if both are not defined. On s390 31bit we have to setup GOT pointer in r12 if we use a PLT stub. Therefore I use SYSCALL_PIC_SETUP from sysdep.h and added the missing semicolons. ChangeLog: [BZ #21537] * sysdeps/s390/s390-32/sysdep.h (JUMPTARGET, SYSCALL_PIC_SETUP): Check SHARED instead of PIC. (SYSCALL_PIC_SETUP): Add missing semicolons. * sysdeps/s390/s390-64/sysdep.h (JUMPTARGET, SYSCALL_PIC_SETUP): Check SHARED instead of PIC. * sysdeps/unix/sysv/linux/s390/s390-32/__makecontext_ret.S (__makecontext_ret): Adjust code to jump to exit. diff --git a/sysdeps/s390/s390-32/sysdep.h b/sysdeps/s390/s390-32/sysdep.h index 15a4e3e..60cf1e7 100644 --- a/sysdeps/s390/s390-32/sysdep.h +++ b/sysdeps/s390/s390-32/sysdep.h @@ -82,14 +82,14 @@ lose: SYSCALL_PIC_SETUP \ END (name) #undef JUMPTARGET -#ifdef PIC +#ifdef SHARED #define JUMPTARGET(name) name##@PLT #define SYSCALL_PIC_SETUP \ - bras %r12,1f \ -0: .long _GLOBAL_OFFSET_TABLE_-0b \ + bras %r12,1f; \ +0: .long _GLOBAL_OFFSET_TABLE_-0b; \ 1: al %r12,0(%r12) #else -#define JUMPTARGET(name) name +#define JUMPTARGET(name) name #define SYSCALL_PIC_SETUP /* Nothing. */ #endif diff --git a/sysdeps/s390/s390-64/sysdep.h b/sysdeps/s390/s390-64/sysdep.h index a4dfc67..419cd01 100644 --- a/sysdeps/s390/s390-64/sysdep.h +++ b/sysdeps/s390/s390-64/sysdep.h @@ -77,7 +77,7 @@ lose: SYSCALL_PIC_SETUP \ END (name) #undef JUMPTARGET -#ifdef PIC +#ifdef SHARED #define JUMPTARGET(name) name##@PLT #define SYSCALL_PIC_SETUP \ larl %r12,_GLOBAL_OFFSET_TABLE_ diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/__makecontext_ret.S b/sysdeps/unix/sysv/linux/s390/s390-32/__makecontext_ret.S index f32cd3c..887d841 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-32/__makecontext_ret.S +++ b/sysdeps/unix/sysv/linux/s390/s390-32/__makecontext_ret.S @@ -32,25 +32,18 @@ ENTRY(__makecontext_ret) lr %r2,%r8 br %r9 1: lhi %r2,0 /* EXIT return value. */ - basr %r13,0 -2: -#ifdef PIC - l %r12,4f-2b(%r13) - la %r12,0(%r12,%r13) /* GOT pointer in r12 after this. */ - l %r1,3f-2b(%r13) - bas %r14,0(%r1,%r12) - .align 4 -3: - .long HIDDEN_JUMPTARGET (exit)@GOTOFF -4: - .long _GLOBAL_OFFSET_TABLE_-2b -#else - l %r1,3f-2b(%r13) - basr %r14,%r1 - .align 4 -3: - .long HIDDEN_JUMPTARGET (exit) +#ifdef NO_HIDDEN + /* If SHARED and NO_HIDDEN is defined, we need to setup got pointer + as HIDDEN_JUMPTARGET expands to JUMPTARGET which expands to + exit@PLT. Otherwise HIDDEN_JUMPTARGET expands to __GI_exit if + SHARED is defined and to exit if SHARED is not defined. */ + SYSCALL_PIC_SETUP #endif - .align 2 + basr %r1,0 +2: + al %r1,3f-2b(%r1) + basr %r14,%r1 /* Call exit. */ j .+2 /* Trap if exit returns for some reason. */ +3: + .long HIDDEN_JUMPTARGET (exit) - 2b END(__makecontext_ret)