glibc/linuxthreads_db/td_thr_tlsbase.c

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/* Locate TLS data for a thread.
Copyright (C) 2003, 2004 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include "thread_dbP.h"
/* Value used for dtv entries for which the allocation is delayed. */
# define TLS_DTV_UNALLOCATED ((void *) -1l)
td_err_e
td_thr_tlsbase (const td_thrhandle_t *th,
unsigned long int modid,
psaddr_t *base)
{
if (modid < 1)
return TD_NOTLS;
#if USE_TLS
union dtv pdtv, *dtvp;
LOG ("td_thr_tlsbase");
psaddr_t dtvpp = th->th_unique;
#if TLS_TCB_AT_TP
dtvpp += offsetof (struct _pthread_descr_struct, p_header.data.dtvp);
#elif TLS_DTV_AT_TP
/* Special case hack. If TLS_TCB_SIZE == 0 (on PowerPC), there is no TCB
containing the DTV at the TP, but actually the TCB lies behind the TP,
i.e. at the very end of the area covered by TLS_PRE_TCB_SIZE. */
dtvpp += TLS_PRE_TCB_SIZE + offsetof (tcbhead_t, dtv)
- (TLS_TCB_SIZE == 0 ? sizeof (tcbhead_t) : 0);
#else
# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined."
#endif
/* Get the DTV pointer from the thread descriptor. */
if (ps_pdread (th->th_ta_p->ph, dtvpp, &dtvp, sizeof dtvp) != PS_OK)
return TD_ERR; /* XXX Other error value? */
/* Get the corresponding entry in the DTV. */
if (ps_pdread (th->th_ta_p->ph, dtvp + modid,
&pdtv, sizeof (union dtv)) != PS_OK)
return TD_ERR; /* XXX Other error value? */
/* It could be that the memory for this module is not allocated for
the given thread. */
if (pdtv.pointer == TLS_DTV_UNALLOCATED)
return TD_TLSDEFER;
*base = (char *) pdtv.pointer;
return TD_OK;
#else
return TD_ERR;
#endif
}