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Fix two subtle problems in PPC32 RTLD. The first is a concurrency issue

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where long PLT calls in multi-threaded environments could end up with
incorrect jmptab values. The second is that, after the addition of extended
PLT support, I forgot to update the PLT icache synchronization code to cover
the extended PLT instead of just the basic PLT.

MFC after:	10 days
This commit is contained in:
nwhitehorn 2010-10-04 16:02:11 +00:00
parent 85d8a2efbb
commit 6a7d71b6f3
1 changed files with 5 additions and 2 deletions
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7
libexec/rtld-elf/powerpc/reloc.c
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@ -38,6 +38,7 @@
#include <string.h>
#include <unistd.h>
#include <machine/cpu.h>
#include <machine/cpufunc.h>
#include <machine/md_var.h>
#include "debug.h"
@ -481,6 +482,7 @@ reloc_jmpslot(Elf_Addr *wherep, Elf_Addr target, const Obj_Entry *defobj,
jmptab = obj->pltgot + JMPTAB_BASE(N);
jmptab[reloff] = target;
powerpc_mb(); /* Order jmptab update before next changes */
if (reloff < PLT_EXTENDED_BEGIN) {
/* for extended PLT entries, we keep the old code */
@ -489,7 +491,8 @@ reloc_jmpslot(Elf_Addr *wherep, Elf_Addr target, const Obj_Entry *defobj,
/* li r11,reloff */
/* b pltcall # use indirect pltcall routine */
wherep[0] = 0x39600000 | reloff;
/* first instruction same as before */
wherep[1] = 0x48000000 | (distance & 0x03fffffc);
__syncicache(wherep, 8);
}
@ -577,7 +580,7 @@ init_pltgot(Obj_Entry *obj)
* Sync the icache for the byte range represented by the
* trampoline routines and call slots.
*/
__syncicache(pltcall, 72 + N * 8);
__syncicache(obj->pltgot, JMPTAB_BASE(N)*4);
}
void