GRU driver: minor updates
A few minor updates for the GRU driver.
- documentation changes found in code reviews
- changes to #ifdefs to make them recognized by "unifdef"
(used in simulator testing)
- change GRU context load/unload to prefetch data
[akpm@linux-foundation.org: fix typo in comment]
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>
diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c
index 3d33015..8c389d60 100644
--- a/drivers/misc/sgi-gru/grufault.c
+++ b/drivers/misc/sgi-gru/grufault.c
@@ -214,12 +214,14 @@
}
/*
- *
* atomic_pte_lookup
*
* Convert a user virtual address to a physical address
* Only supports Intel large pages (2MB only) on x86_64.
* ZZZ - hugepage support is incomplete
+ *
+ * NOTE: mmap_sem is already held on entry to this function. This
+ * guarantees existence of the page tables.
*/
static int atomic_pte_lookup(struct vm_area_struct *vma, unsigned long vaddr,
int write, unsigned long *paddr, int *pageshift)
@@ -229,9 +231,6 @@
pud_t *pudp;
pte_t pte;
- WARN_ON(irqs_disabled()); /* ZZZ debug */
-
- local_irq_disable();
pgdp = pgd_offset(vma->vm_mm, vaddr);
if (unlikely(pgd_none(*pgdp)))
goto err;
@@ -250,8 +249,6 @@
#endif
pte = *pte_offset_kernel(pmdp, vaddr);
- local_irq_enable();
-
if (unlikely(!pte_present(pte) ||
(write && (!pte_write(pte) || !pte_dirty(pte)))))
return 1;
@@ -324,6 +321,7 @@
* Atomic lookup is faster & usually works even if called in non-atomic
* context.
*/
+ rmb(); /* Must/check ms_range_active before loading PTEs */
ret = atomic_pte_lookup(vma, vaddr, write, &paddr, &pageshift);
if (ret) {
if (!cb)
@@ -543,6 +541,7 @@
ucbnum = get_cb_number((void *)excdet.cb);
cbrnum = thread_cbr_number(gts, ucbnum);
cbe = get_cbe_by_index(gts->ts_gru, cbrnum);
+ prefetchw(cbe); /* Harmless on hardware, required for emulator */
excdet.opc = cbe->opccpy;
excdet.exopc = cbe->exopccpy;
excdet.ecause = cbe->ecause;
