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gru: bug fixes for GRU exception handling

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Bug fixes for GRU exception handling.  Additional fields from the CBR must
be returned to the user to allow the user to correctly diagnose GRU
exceptions.

Handle endcase in TFH TLB miss handling.  Verify that TFH actually
indicates a pending exception.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jack Steiner
2009-06-17 16:28:19 -07:00
committed by Linus Torvalds
parent d6580a9f15
commit cd1334f03f
6 changed files with 52 additions and 26 deletions
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25
drivers/misc/sgi-gru/grufault.c
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@@ -334,6 +334,8 @@ static int gru_try_dropin(struct gru_thread_state *gts,
* Might be a hardware race OR a stupid user. Ignore FMM because FMM
* is a transient state.
*/
if (tfh->status != TFHSTATUS_EXCEPTION)
goto failnoexception;
if (tfh->state == TFHSTATE_IDLE)
goto failidle;
if (tfh->state == TFHSTATE_MISS_FMM && cb)
@@ -401,8 +403,17 @@ failfmm:
gru_dbg(grudev, "FAILED fmm tfh: 0x%p, state %d\n", tfh, tfh->state);
return 0;
failnoexception:
/* TFH status did not show exception pending */
gru_flush_cache(tfh);
if (cb)
gru_flush_cache(cb);
STAT(tlb_dropin_fail_no_exception);
gru_dbg(grudev, "FAILED non-exception tfh: 0x%p, status %d, state %d\n", tfh, tfh->status, tfh->state);
return 0;
failidle:
/* TFH was idle - no miss pending */
/* TFH state was idle - no miss pending */
gru_flush_cache(tfh);
if (cb)
gru_flush_cache(cb);
@@ -472,7 +483,8 @@ irqreturn_t gru_intr(int irq, void *dev_id)
* This is running in interrupt context. Trylock the mmap_sem.
* If it fails, retry the fault in user context.
*/
if (down_read_trylock(&gts->ts_mm->mmap_sem)) {
if (!gts->ts_force_cch_reload &&
down_read_trylock(&gts->ts_mm->mmap_sem)) {
gru_try_dropin(gts, tfh, NULL);
up_read(&gts->ts_mm->mmap_sem);
} else {
@@ -595,14 +607,19 @@ int gru_get_exception_detail(unsigned long arg)
excdet.ecause = cbe->ecause;
excdet.exceptdet0 = cbe->idef1upd;
excdet.exceptdet1 = cbe->idef3upd;
excdet.cbrstate = cbe->cbrstate;
excdet.cbrexecstatus = cbe->cbrexecstatus;
ret = 0;
} else {
ret = -EAGAIN;
}
gru_unlock_gts(gts);
gru_dbg(grudev, "address 0x%lx, ecause 0x%x\n", excdet.cb,
excdet.ecause);
gru_dbg(grudev,
"cb 0x%lx, op %d, exopc %d, cbrstate %d, cbrexecstatus 0x%x, ecause 0x%x, "
"exdet0 0x%lx, exdet1 0x%x\n",
excdet.cb, excdet.opc, excdet.exopc, excdet.cbrstate, excdet.cbrexecstatus,
excdet.ecause, excdet.exceptdet0, excdet.exceptdet1);
if (!ret && copy_to_user((void __user *)arg, &excdet, sizeof(excdet)))
ret = -EFAULT;
return ret;