[PATCH v3 22/45] powerpc/mm: Create a dedicated pte_update() for 8xx

From: Christophe Leroy
Date: Mon May 11 2020 - 07:27:52 EST


pte_update() is a bit special for the 8xx. At the time
being, that's an #ifdef inside the nohash/32 pte_update().

As we are going to make it even more special in the coming
patches, create a dedicated version for pte_update() for 8xx.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
arch/powerpc/include/asm/nohash/32/pgtable.h | 29 +++++++++++++++++---
1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h b/arch/powerpc/include/asm/nohash/32/pgtable.h
index 75880eb1cb91..272963a05ab2 100644
--- a/arch/powerpc/include/asm/nohash/32/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
@@ -221,7 +221,31 @@ static inline void pmd_clear(pmd_t *pmdp)
* that an executable user mapping was modified, which is needed
* to properly flush the virtually tagged instruction cache of
* those implementations.
+ *
+ * On the 8xx, the page tables are a bit special. For 16k pages, we have
+ * 4 identical entries. For other page sizes, we have a single entry in the
+ * table.
*/
+#ifdef CONFIG_PPC_8xx
+static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, pte_t *p,
+ unsigned long clr, unsigned long set, int huge)
+{
+ pte_basic_t *entry = &p->pte;
+ pte_basic_t old = pte_val(*p);
+ pte_basic_t new = (old & ~(pte_basic_t)clr) | set;
+ int num, i;
+
+ if (!huge)
+ num = PAGE_SIZE / SZ_4K;
+ else
+ num = 1;
+
+ for (i = 0; i < num; i++, entry++)
+ *entry = new;
+
+ return old;
+}
+#else
static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, pte_t *p,
unsigned long clr, unsigned long set, int huge)
{
@@ -242,11 +266,7 @@ static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, p
pte_basic_t old = pte_val(*p);
pte_basic_t new = (old & ~(pte_basic_t)clr) | set;

-#if defined(CONFIG_PPC_8xx) && defined(CONFIG_PPC_16K_PAGES)
- p->pte = p->pte1 = p->pte2 = p->pte3 = new;
-#else
*p = __pte(new);
-#endif
#endif /* !PTE_ATOMIC_UPDATES */

#ifdef CONFIG_44x
@@ -255,6 +275,7 @@ static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, p
#endif
return old;
}
+#endif

#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
static inline int __ptep_test_and_clear_young(struct mm_struct *mm,
--
2.25.0