Revert "convert SLB miss handlers to C" and subsequent commits

This reverts commits:
  5e46e29e6a97 ("powerpc/64s/hash: convert SLB miss handlers to C")
  8fed04d0f6ae ("powerpc/64s/hash: remove user SLB data from the paca")
  655deecf67b2 ("powerpc/64s/hash: SLB allocation status bitmaps")
  2e1626744e8d ("powerpc/64s/hash: provide arch_setup_exec hooks for hash slice setup")
  89ca4e126a3f ("powerpc/64s/hash: Add a SLB preload cache")

This series had a few bugs, and the fixes are not all trivial. So
revert most of it for now.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 35 insertions, 11 deletions

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 88c95dc8b141..f23a89d8e4ce 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1088,16 +1088,16 @@ unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap)
 }
 
 #ifdef CONFIG_PPC_MM_SLICES
-static unsigned int get_psize(struct mm_struct *mm, unsigned long addr)
+static unsigned int get_paca_psize(unsigned long addr)
 {
 	unsigned char *psizes;
 	unsigned long index, mask_index;
 
 	if (addr < SLICE_LOW_TOP) {
-		psizes = mm->context.low_slices_psize;
+		psizes = get_paca()->mm_ctx_low_slices_psize;
 		index = GET_LOW_SLICE_INDEX(addr);
 	} else {
-		psizes = mm->context.high_slices_psize;
+		psizes = get_paca()->mm_ctx_high_slices_psize;
 		index = GET_HIGH_SLICE_INDEX(addr);
 	}
 	mask_index = index & 0x1;
@@ -1105,9 +1105,9 @@ static unsigned int get_psize(struct mm_struct *mm, unsigned long addr)
 }
 
 #else
-unsigned int get_psize(struct mm_struct *mm, unsigned long addr)
+unsigned int get_paca_psize(unsigned long addr)
 {
-	return mm->context.user_psize;
+	return get_paca()->mm_ctx_user_psize;
 }
 #endif
 
@@ -1118,11 +1118,15 @@ unsigned int get_psize(struct mm_struct *mm, unsigned long addr)
 #ifdef CONFIG_PPC_64K_PAGES
 void demote_segment_4k(struct mm_struct *mm, unsigned long addr)
 {
-	if (get_psize(mm, addr) == MMU_PAGE_4K)
+	if (get_slice_psize(mm, addr) == MMU_PAGE_4K)
 		return;
 	slice_set_range_psize(mm, addr, 1, MMU_PAGE_4K);
 	copro_flush_all_slbs(mm);
-	core_flush_all_slbs(mm);
+	if ((get_paca_psize(addr) != MMU_PAGE_4K) && (current->mm == mm)) {
+
+		copy_mm_to_paca(mm);
+		slb_flush_and_rebolt();
+	}
 }
 #endif /* CONFIG_PPC_64K_PAGES */
 
@@ -1187,6 +1191,22 @@ void hash_failure_debug(unsigned long ea, unsigned long access,
 		trap, vsid, ssize, psize, lpsize, pte);
 }
 
+static void check_paca_psize(unsigned long ea, struct mm_struct *mm,
+			     int psize, bool user_region)
+{
+	if (user_region) {
+		if (psize != get_paca_psize(ea)) {
+			copy_mm_to_paca(mm);
+			slb_flush_and_rebolt();
+		}
+	} else if (get_paca()->vmalloc_sllp !=
+		   mmu_psize_defs[mmu_vmalloc_psize].sllp) {
+		get_paca()->vmalloc_sllp =
+			mmu_psize_defs[mmu_vmalloc_psize].sllp;
+		slb_vmalloc_update();
+	}
+}
+
 /* Result code is:
  *  0 - handled
  *  1 - normal page fault
@@ -1219,7 +1239,7 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea,
 			rc = 1;
 			goto bail;
 		}
-		psize = get_psize(mm, ea);
+		psize = get_slice_psize(mm, ea);
 		ssize = user_segment_size(ea);
 		vsid = get_user_vsid(&mm->context, ea, ssize);
 		break;
@@ -1307,6 +1327,9 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea,
 			WARN_ON(1);
 		}
 #endif
+		if (current->mm == mm)
+			check_paca_psize(ea, mm, psize, user_region);
+
 		goto bail;
 	}
 
@@ -1341,14 +1364,15 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea,
 			       "to 4kB pages because of "
 			       "non-cacheable mapping\n");
 			psize = mmu_vmalloc_psize = MMU_PAGE_4K;
-			slb_vmalloc_update();
 			copro_flush_all_slbs(mm);
-			core_flush_all_slbs(mm);
 		}
 	}
 
 #endif /* CONFIG_PPC_64K_PAGES */
 
+	if (current->mm == mm)
+		check_paca_psize(ea, mm, psize, user_region);
+
 #ifdef CONFIG_PPC_64K_PAGES
 	if (psize == MMU_PAGE_64K)
 		rc = __hash_page_64K(ea, access, vsid, ptep, trap,
@@ -1436,7 +1460,7 @@ int __hash_page(unsigned long ea, unsigned long msr, unsigned long trap,
 #ifdef CONFIG_PPC_MM_SLICES
 static bool should_hash_preload(struct mm_struct *mm, unsigned long ea)
 {
-	int psize = get_psize(mm, ea);
+	int psize = get_slice_psize(mm, ea);
 
 	/* We only prefault standard pages for now */
 	if (unlikely(psize != mm->context.user_psize))