powerpc: hugetlb: fix huge_ptep_set_access_flags return value

There was an unconditional return of "1" in the original code
from David Gibson, and I dropped it because it wasn't needed
for FSL BOOKE 32-bit.  However, not all systems (including 64-bit
FSL BOOKE) do loading of the hpte from the fault handler asm
and depend on this function returning 1, which causes a call
to update_mmu_cache() that writes an entry into the tlb.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/hugetlb.h b/arch/powerpc/include/asm/hugetlb.h
index 86004930a78e..70f9885f5c0f 100644
--- a/arch/powerpc/include/asm/hugetlb.h
+++ b/arch/powerpc/include/asm/hugetlb.h
@@ -124,7 +124,18 @@ static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 					     unsigned long addr, pte_t *ptep,
 					     pte_t pte, int dirty)
 {
+#if defined(CONFIG_PPC_MMU_NOHASH) && \
+	!(defined(CONFIG_PPC_FSL_BOOK3E) && defined(CONFIG_PPC32))
+	/*
+	 * The "return 1" forces a call of update_mmu_cache, which will write a
+	 * TLB entry.  Without this, platforms that don't do a write of the TLB
+	 * entry in the TLB miss handler asm will fault ad infinitum.
+	 */
+	ptep_set_access_flags(vma, addr, ptep, pte, dirty);
+	return 1;
+#else
 	return ptep_set_access_flags(vma, addr, ptep, pte, dirty);
+#endif
 }
 
 static inline pte_t huge_ptep_get(pte_t *ptep)