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elf: Use C11 atomics on _dl_mcount 

All atomic operation are counters, so relaxed MO should be suffice.

Checked on x86_64-linux-gnu.
Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
This commit is contained in:
Adhemerval Zanella 2022-09-20 16:04:13 -03:00
parent c0c9092f75
commit fd36873ff9
1 changed files with 5 additions and 5 deletions
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10
elf/dl-profile.c
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@ -548,7 +548,7 @@ _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc)
size_t newfromidx;
to_index = (data[narcs].self_pc
/ (HASHFRACTION * sizeof (*tos)));
newfromidx = catomic_exchange_and_add (&fromidx, 1) + 1;
newfromidx = atomic_fetch_add_relaxed (&fromidx, 1) + 1;
froms[newfromidx].here = &data[narcs];
froms[newfromidx].link = tos[to_index];
tos[to_index] = newfromidx;
@ -558,14 +558,14 @@ _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc)
/* If we still have no entry stop searching and insert. */
if (*topcindex == 0)
{
unsigned int newarc = catomic_exchange_and_add (narcsp, 1);
unsigned int newarc = atomic_fetch_add_relaxed (narcsp, 1);
/* In rare cases it could happen that all entries in FROMS are
occupied. So we cannot count this anymore. */
if (newarc >= fromlimit)
goto done;
*topcindex = catomic_exchange_and_add (&fromidx, 1) + 1;
*topcindex = atomic_fetch_add_relaxed (&fromidx, 1) + 1;
fromp = &froms[*topcindex];
fromp->here = &data[newarc];
@ -573,7 +573,7 @@ _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc)
data[newarc].self_pc = selfpc;
data[newarc].count = 0;
fromp->link = 0;
catomic_increment (&narcs);
atomic_fetch_add_relaxed (&narcs, 1);
break;
}
@ -586,7 +586,7 @@ _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc)
}
/* Increment the counter. */
catomic_increment (&fromp->here->count);
atomic_fetch_add_relaxed (&fromp->here->count, 1);
done:
;