powerpc/mm: move update_mmu_cache() into book3s hash utils.

update_mmu_cache() is only for BOOK3S, and can be simplified for
BOOK3S32.

Move it out of mem.c into respective BOOK3S32 and BOOK3S64 files
containing hash utils.

BOOK3S64 version of hash_preload() is only used locally, declare it
static.

Remove the radix_enabled() stuff in BOOK3S32 version.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/107aaf43583a5f5d09e0d4e84c4c4390ecfcd512.1565933217.git.christophe.leroy@c-s.fr

1 files changed, 46 insertions, 0 deletions

diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c
index 8d68f03bf5a4..1e77dca8b497 100644
--- a/arch/powerpc/mm/book3s32/mmu.c
+++ b/arch/powerpc/mm/book3s32/mmu.c
@@ -310,6 +310,52 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
 }
 
 /*
+ * This is called at the end of handling a user page fault, when the
+ * fault has been handled by updating a PTE in the linux page tables.
+ * We use it to preload an HPTE into the hash table corresponding to
+ * the updated linux PTE.
+ *
+ * This must always be called with the pte lock held.
+ */
+void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
+		      pte_t *ptep)
+{
+	/*
+	 * We don't need to worry about _PAGE_PRESENT here because we are
+	 * called with either mm->page_table_lock held or ptl lock held
+	 */
+	unsigned long trap;
+	bool is_exec;
+
+	/* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
+	if (!pte_young(*ptep) || address >= TASK_SIZE)
+		return;
+
+	/*
+	 * We try to figure out if we are coming from an instruction
+	 * access fault and pass that down to __hash_page so we avoid
+	 * double-faulting on execution of fresh text. We have to test
+	 * for regs NULL since init will get here first thing at boot.
+	 *
+	 * We also avoid filling the hash if not coming from a fault.
+	 */
+
+	trap = current->thread.regs ? TRAP(current->thread.regs) : 0UL;
+	switch (trap) {
+	case 0x300:
+		is_exec = false;
+		break;
+	case 0x400:
+		is_exec = true;
+		break;
+	default:
+		return;
+	}
+
+	hash_preload(vma->vm_mm, address, is_exec, trap);
+}
+
+/*
  * Initialize the hash table and patch the instructions in hashtable.S.
  */
 void __init MMU_init_hw(void)