/*
* Initialize the transaction descriptor before start or restart.
*/
static inline void stm_prepare(stm_tx_t *tx)
{
start:
/* Start timestamp */
tx->start = tx->end = GET_CLOCK; /* OPT: Could be delayed until first read/write */
/* Allow extensions */
tx->can_extend = 1;
if (tx->start >= VERSION_MAX) {
/* Block all transactions and reset clock */
stm_quiesce_barrier(tx, rollover_clock, NULL);
goto start;
}
/* Read/write set */
tx->w_set.has_writes = 0;
tx->w_set.nb_entries = 0;
tx->r_set.nb_entries = 0;
/* Set status */
UPDATE_STATUS(tx->status, TX_ACTIVE);
stm_check_quiesce(tx);
}
sigjmp_buf *
hytm_start(TXPARAMS stm_tx_attr_t attr)
{
TX_GET;
unsigned long err;
tx->retries = 0;
/* Set status */
UPDATE_STATUS(tx->status, TX_ACTIVE);
stm_check_quiesce(tx);
/* copy attributes if need to switch to software mode */
tx->attr = attr;
tx->start = rdtsc();
hytm_restart:
/* All registers are lost when ASF aborts, thus we discard registers */
asm volatile (ASF_SPECULATE
:"=a" (err)
:
:"memory","rbp","rbx","rcx","rdx","rsi","rdi",
"r8", "r9","r10","r11","r12","r13","r14","r15" );
tx = tls_get_tx();
if (unlikely(asf_status_code(err) != 0)) {
/* Set status to ABORTED */
SET_STATUS(tx->status, TX_ABORTED);
tx->retries++;
/* Error management */
if (asf_status_code(err) == ASF_STATUS_CONTENTION) {
if (tx->retries > ASF_ABORT_THRESHOLD) {
/* There is too many conflicts, software will not help, start irrevocability. */
stm_set_irrevocable(TXARGS 1); /* Set irrevocable serial */
#if defined(TM_DTMC) || defined(TM_GCC)
stm_set_irrevocable(TXARGS -1); /* Acquire irrevocability */
UPDATE_STATUS(tx->status, TX_IRREVOCABLE);
LONGJMP(tx->env, 0x02); /* ABI 0x02 = runUninstrumented */
#else /* ! defined(TM_DTMC) && ! defined(TM_GCC) */
/* Non-tm compiler doesn't have path without instrumentation. */
tx->software = 1;
#endif /* ! defined(TM_DTMC) && ! defined(TM_GCC) */
}
} else if (asf_status_code(err) == ASF_STATUS_ABORT) {
if (asf_abort_code(err) == ASF_FORCE_SOFTWARE) {
tx->software = 1;
#ifdef IRREVOCABLE_ENABLED
} else if(asf_abort_code(err) == ASF_RETRY_IRREVOCABLE) {
# if defined(TM_DTMC) || defined(TM_GCC)
if (tx->irrevocable != 0) {
stm_set_irrevocable(TXARGS -1);
UPDATE_STATUS(tx->status, TX_IRREVOCABLE);
LONGJMP(tx->env, 0x02); /* ABI 0x02 = runUninstrumented */
}
# else /* ! defined(TM_DTMC) || defined(TM_GCC) */
/* Non-tm compiler doesn't have path without instrumentation. */
tx->software = 1;
# endif /* ! defined(TM_DTMC) || defined(TM_GCC) */
#endif /* IRREVOCABLE_ENABLED */
} else {
if (tx->retries > ASF_ABORT_THRESHOLD) {
tx->software = 1;
}
}
} else {
/* Other cases are critical and needs software mode */
tx->software = 1;
}
if (tx->software) {
/* Start a software transaction (it cannot use attr since the register/stack can be corrupted) */
stm_start(TXARGS tx->attr);
/* Restoring the context */
#if defined(TM_DTMC)
LONGJMP(tx->env, 0x01); /* ABI 0x01 = runInstrumented, DTMC explicitly needs 1 */
#else /* ! defined(TM_DTMC) */
LONGJMP(tx->env, 0x09); /* ABI 0x09 = runInstrumented + restoreLiveVariable */
#endif /* ! defined(TM_DTMC) */
} else {
uint64_t cur = (uint64_t)rdtsc();
uint64_t wait = cur + (random() % (cur - tx->start)); /* XXX random but maybe not reliable */
/* Waiting... */
while (rdtsc() < wait);
UPDATE_STATUS(tx->status, TX_ACTIVE);
/* Check quiesce before to restart */
stm_check_quiesce(tx);
goto hytm_restart;
}
}
/* Reset write set */
tx->w_set.nb_entries = 0;
if (tx->retries > 0) {
/* Restoring registers for retry */
#if defined(TM_DTMC)
LONGJMP(tx->env, 0x01); /* ABI 0x01 = runInstrumented, DTMC explicitly needs 1 */
#else /* ! defined(TM_DTMC) */
LONGJMP(tx->env, 0x09); /* ABI 0x09 = runInstrumented + restoreLiveVariable */
#endif /* ! defined(TM_DTMC) */
}
return &tx->env;
}