From 4603c51ef7989d7eb800cdd6f42aab206f891077 Mon Sep 17 00:00:00 2001 From: Stefan Liebler Date: Thu, 31 Mar 2016 17:37:16 +0200 Subject: S390: Save and restore fprs/vrs while resolving symbols. On s390, no fpr/vrs were saved while resolving a symbol via _dl_runtime_resolve/_dl_runtime_profile. According to the abi, the fpr-arguments are defined as call clobbered. In leaf-functions, gcc 4.9 and newer can use fprs for saving/restoring gprs instead of saving them to the stack. If gcc do this in one of the resolver-functions, then the floating point arguments of a library-function are invalid for the first library-function-call. Thus, this patch saves/restores the fprs around the resolving code. The same could occur for vector registers. Furthermore an ifunc-resolver could also clobber the vector/floating point argument registers. Thus this patch provides the further variants _dl_runtime_resolve_vx/ _dl_runtime_profile_vx, which are used if the kernel claims, that we run on a machine with vector registers. Furthermore, if _dl_runtime_profile calls _dl_call_pltexit, the pointers to inregs-/outregs-structs were setup invalid. Now they point to the correct location in the stack-frame. Before branching back to the caller, the return values are now restored instead of containing the return values of the _dl_call_pltexit() call. On s390-32, an endless loop occurs if _dl_call_pltexit() should be called. Now, this code-path branches to this function instead of just after the preceding basr-instruction. ChangeLog: * sysdeps/s390/s390-32/dl-trampoline.S: Include dl-trampoline.h twice to create a non-vector/vector version for _dl_runtime_resolve and _dl_runtime_profile. Move implementation to ... * sysdeps/s390/s390-32/dl-trampoline.h: ... here. (_dl_runtime_resolve) Save and restore fpr/vrs. (_dl_runtime_profile) Save and restore vrs and fix some issues if _dl_call_pltexit is called. * sysdeps/s390/s390-32/dl-machine.h (elf_machine_runtime_setup): Choose the correct resolver function if running on a machine with vx. * sysdeps/s390/s390-64/dl-trampoline.S: Include dl-trampoline.h twice to create a non-vector/vector version for _dl_runtime_resolve and _dl_runtime_profile. Move implementation to ... * sysdeps/s390/s390-64/dl-trampoline.h: ... here. (_dl_runtime_resolve) Save and restore fpr/vrs. (_dl_runtime_profile) Save and restore vrs and fix some issues * sysdeps/s390/s390-64/dl-machine.h: (elf_machine_runtime_setup): Choose the correct resolver function if running on a machine with vx. --- sysdeps/s390/s390-64/dl-trampoline.S | 130 +++-------------------------------- 1 file changed, 11 insertions(+), 119 deletions(-) (limited to 'sysdeps/s390/s390-64/dl-trampoline.S') diff --git a/sysdeps/s390/s390-64/dl-trampoline.S b/sysdeps/s390/s390-64/dl-trampoline.S index 6919ed0138..1b0c9e2680 100644 --- a/sysdeps/s390/s390-64/dl-trampoline.S +++ b/sysdeps/s390/s390-64/dl-trampoline.S @@ -16,126 +16,18 @@ License along with the GNU C Library; if not, see . */ -/* The PLT stubs will call _dl_runtime_resolve/_dl_runtime_profile - * with the following linkage: - * r2 - r6 : parameter registers - * f0, f2, f4, f6 : floating point parameter registers - * 48(r15), 56(r15) : PLT arguments PLT1, PLT2 - * 160(r15) : additional stack parameters - * The normal clobber rules for function calls apply: - * r0 - r5 : call clobbered - * r6 - r13 : call saved - * r14 : return address (call clobbered) - * r15 : stack pointer (call saved) - * f1, f3, f5, f7 : call saved - * f0 - f3, f5, f7 - f15 : call clobbered - */ - #include .text - .globl _dl_runtime_resolve - .type _dl_runtime_resolve, @function - cfi_startproc - .align 16 -_dl_runtime_resolve: - stmg %r2,%r5,64(15) # save call-clobbered argument registers - stg %r14,96(15) - cfi_offset (r14, -64) - lgr %r0,%r15 - aghi %r15,-160 # create stack frame - cfi_adjust_cfa_offset (160) - stg %r0,0(%r15) # write backchain - lmg %r2,%r3,208(%r15)# load args saved by PLT - brasl %r14,_dl_fixup # call fixup - lgr %r1,%r2 # function addr returned in r2 - aghi %r15,160 # remove stack frame - cfi_adjust_cfa_offset (-160) - lg %r14,96(15) # restore registers - lmg %r2,%r5,64(15) - br %r1 - cfi_endproc - .size _dl_runtime_resolve, .-_dl_runtime_resolve - - -#ifndef PROF - .globl _dl_runtime_profile - .type _dl_runtime_profile, @function - cfi_startproc - .align 16 -_dl_runtime_profile: - stmg %r2,%r6,64(%r15) # save call-clobbered arg regs - std %f0,104(%r15) # + r6 needed as arg for - std %f2,112(%r15) # _dl_profile_fixup - std %f4,120(%r15) - std %f6,128(%r15) - stg %r12,24(%r15) # r12 is used as backup of r15 - stg %r14,32(%r15) - cfi_offset (r6, -96) - cfi_offset (f0, -56) - cfi_offset (f2, -48) - cfi_offset (f4, -40) - cfi_offset (f6, -32) - cfi_offset (r12, -136) - cfi_offset (r14, -128) - lgr %r12,%r15 # backup stack pointer - cfi_def_cfa_register (12) - aghi %r15,-160 # create stack frame - stg %r12,0(%r15) # save backchain - lmg %r2,%r3,48(%r12) # load arguments saved by PLT - lgr %r4,%r14 # return address as third parameter - la %r5,64(%r12) # pointer to struct La_s390_32_regs - la %r6,40(%r12) # long int * framesize - brasl %r14,_dl_profile_fixup # call resolver - lgr %r1,%r2 # function addr returned in r2 - lg %r0,40(%r12) # load framesize - ltgr %r0,%r0 - jnm 1f - - lmg %r2,%r6,64(%r12) # framesize < 0 means no pltexit call - ld %f0,104(%r12) # so we can do a tail call without - ld %f2,112(%r12) # copying the arg overflow area - ld %f4,120(%r12) - ld %f6,128(%r12) - - lgr %r15,%r12 # remove stack frame - cfi_def_cfa_register (15) - lg %r14,32(%r15) # restore registers - lg %r12,24(%r15) - br %r1 # tail-call to resolved function - - cfi_def_cfa_register (12) -1: jz 4f # framesize == 0 ? - aghi %r0,7 # align framesize to 8 - nill %r0,0xfff8 - slgr %r15,%r0 # make room for framesize bytes - stg %r12,0(%r15) - la %r2,160(%r15) - la %r3,160(%r12) - srlg %r0,%r0,3 -3: mvc 0(8,%r2),0(%r3) # copy additional parameters - la %r2,8(%r2) - la %r3,8(%r3) - brctg %r0,3b -4: lmg %r2,%r6,64(%r12) # load register parameters - ld %f0,104(%r12) # restore call-clobbered arg regs - ld %f2,112(%r12) - ld %f4,120(%r12) - ld %f6,128(%r12) - basr %r14,%r1 # call resolved function - stg %r2,136(%r12) - std %f0,144(%r12) - lmg %r2,%r3,48(%r12) # load arguments saved by PLT - la %r4,32(%r12) # pointer to struct La_s390_32_regs - la %r5,72(%r12) # pointer to struct La_s390_32_retval - brasl %r14,_dl_call_pltexit - - lgr %r15,%r12 # remove stack frame - cfi_def_cfa_register (15) - lg %r14,32(%r15) # restore registers - lg %r12,24(%r15) - br %r14 - - cfi_endproc - .size _dl_runtime_profile, .-_dl_runtime_profile +/* Create variant of _dl_runtime_resolve/profile for machines before z13. + No vector registers are saved/restored. */ +#include + +#if defined HAVE_S390_VX_ASM_SUPPORT +/* Create variant of _dl_runtime_resolve/profile for z13 and newer. + The vector registers are saved/restored, too.*/ +# define _dl_runtime_resolve _dl_runtime_resolve_vx +# define _dl_runtime_profile _dl_runtime_profile_vx +# define RESTORE_VRS +# include #endif -- cgit 1.4.1