1 files changed, 111 insertions, 16 deletions

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 3c7fe2c65b5a..49618461defb 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -100,6 +100,11 @@ unsigned int HPAGE_SHIFT;
 #ifdef CONFIG_PPC_64K_PAGES
 int mmu_ci_restrictions;
 #endif
+#ifdef CONFIG_DEBUG_PAGEALLOC
+static u8 *linear_map_hash_slots;
+static unsigned long linear_map_hash_count;
+static spinlock_t linear_map_hash_lock;
+#endif /* CONFIG_DEBUG_PAGEALLOC */
 
 /* There are definitions of page sizes arrays to be used when none
  * is provided by the firmware.
@@ -152,11 +157,10 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
 
         for (vaddr = vstart, paddr = pstart; vaddr < vend;
              vaddr += step, paddr += step) {
-                unsigned long vpn, hash, hpteg;
+                unsigned long hash, hpteg;
                 unsigned long vsid = get_kernel_vsid(vaddr);
                 unsigned long va = (vsid << 28) | (vaddr & 0x0fffffff);
 
-                vpn = va >> shift;
                 tmp_mode = mode;
                 
                 /* Make non-kernel text non-executable */
@@ -174,6 +178,10 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
 
                 if (ret < 0)
                         break;
+#ifdef CONFIG_DEBUG_PAGEALLOC
+                if ((paddr >> PAGE_SHIFT) < linear_map_hash_count)
+                        linear_map_hash_slots[paddr >> PAGE_SHIFT] = ret | 0x80;
+#endif /* CONFIG_DEBUG_PAGEALLOC */
         }
         return ret < 0 ? ret : 0;
 }
@@ -281,6 +289,7 @@ static void __init htab_init_page_sizes(void)
                 memcpy(mmu_psize_defs, mmu_psize_defaults_gp,
                        sizeof(mmu_psize_defaults_gp));
  found:
+#ifndef CONFIG_DEBUG_PAGEALLOC
         /*
          * Pick a size for the linear mapping. Currently, we only support
          * 16M, 1M and 4K which is the default
@@ -289,6 +298,7 @@ static void __init htab_init_page_sizes(void)
                 mmu_linear_psize = MMU_PAGE_16M;
         else if (mmu_psize_defs[MMU_PAGE_1M].shift)
                 mmu_linear_psize = MMU_PAGE_1M;
+#endif /* CONFIG_DEBUG_PAGEALLOC */
 
 #ifdef CONFIG_PPC_64K_PAGES
         /*
@@ -303,12 +313,14 @@ static void __init htab_init_page_sizes(void)
         if (mmu_psize_defs[MMU_PAGE_64K].shift) {
                 mmu_virtual_psize = MMU_PAGE_64K;
                 mmu_vmalloc_psize = MMU_PAGE_64K;
+                if (mmu_linear_psize == MMU_PAGE_4K)
+                        mmu_linear_psize = MMU_PAGE_64K;
                 if (cpu_has_feature(CPU_FTR_CI_LARGE_PAGE))
                         mmu_io_psize = MMU_PAGE_64K;
                 else
                         mmu_ci_restrictions = 1;
         }
-#endif
+#endif /* CONFIG_PPC_64K_PAGES */
 
         printk(KERN_DEBUG "Page orders: linear mapping = %d, "
                "virtual = %d, io = %d\n",
@@ -476,6 +488,13 @@ void __init htab_initialize(void)
 
         mode_rw = _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_COHERENT | PP_RWXX;
 
+#ifdef CONFIG_DEBUG_PAGEALLOC
+        linear_map_hash_count = lmb_end_of_DRAM() >> PAGE_SHIFT;
+        linear_map_hash_slots = __va(lmb_alloc_base(linear_map_hash_count,
+                                                    1, lmb.rmo_size));
+        memset(linear_map_hash_slots, 0, linear_map_hash_count);
+#endif /* CONFIG_DEBUG_PAGEALLOC */
+
         /* On U3 based machines, we need to reserve the DART area and
          * _NOT_ map it to avoid cache paradoxes as it's remapped non
          * cacheable later on
@@ -573,6 +592,27 @@ unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap)
         return pp;
 }
 
+/*
+ * Demote a segment to using 4k pages.
+ * For now this makes the whole process use 4k pages.
+ */
+void demote_segment_4k(struct mm_struct *mm, unsigned long addr)
+{
+#ifdef CONFIG_PPC_64K_PAGES
+        if (mm->context.user_psize == MMU_PAGE_4K)
+                return;
+        mm->context.user_psize = MMU_PAGE_4K;
+        mm->context.sllp = SLB_VSID_USER | mmu_psize_defs[MMU_PAGE_4K].sllp;
+        get_paca()->context = mm->context;
+        slb_flush_and_rebolt();
+#ifdef CONFIG_SPE_BASE
+        spu_flush_all_slbs(mm);
+#endif
+#endif
+}
+
+EXPORT_SYMBOL_GPL(demote_segment_4k);
+
 /* Result code is:
  *  0 - handled
  *  1 - normal page fault
@@ -665,15 +705,19 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
 #ifndef CONFIG_PPC_64K_PAGES
         rc = __hash_page_4K(ea, access, vsid, ptep, trap, local);
 #else
+        /* If _PAGE_4K_PFN is set, make sure this is a 4k segment */
+        if (pte_val(*ptep) & _PAGE_4K_PFN) {
+                demote_segment_4k(mm, ea);
+                psize = MMU_PAGE_4K;
+        }
+
         if (mmu_ci_restrictions) {
                 /* If this PTE is non-cacheable, switch to 4k */
                 if (psize == MMU_PAGE_64K &&
                     (pte_val(*ptep) & _PAGE_NO_CACHE)) {
                         if (user_region) {
+                                demote_segment_4k(mm, ea);
                                 psize = MMU_PAGE_4K;
-                                mm->context.user_psize = MMU_PAGE_4K;
-                                mm->context.sllp = SLB_VSID_USER |
-                                        mmu_psize_defs[MMU_PAGE_4K].sllp;
                         } else if (ea < VMALLOC_END) {
                                 /*
                                  * some driver did a non-cacheable mapping
@@ -756,16 +800,8 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
         if (mmu_ci_restrictions) {
                 /* If this PTE is non-cacheable, switch to 4k */
                 if (mm->context.user_psize == MMU_PAGE_64K &&
-                    (pte_val(*ptep) & _PAGE_NO_CACHE)) {
-                        mm->context.user_psize = MMU_PAGE_4K;
-                        mm->context.sllp = SLB_VSID_USER |
-                                mmu_psize_defs[MMU_PAGE_4K].sllp;
-                        get_paca()->context = mm->context;
-                        slb_flush_and_rebolt();
-#ifdef CONFIG_SPE_BASE
-                        spu_flush_all_slbs(mm);
-#endif
-                }
+                    (pte_val(*ptep) & _PAGE_NO_CACHE))
+                        demote_segment_4k(mm, ea);
         }
         if (mm->context.user_psize == MMU_PAGE_64K)
                 __hash_page_64K(ea, access, vsid, ptep, trap, local);
@@ -825,3 +861,62 @@ void low_hash_fault(struct pt_regs *regs, unsigned long address)
         }
         bad_page_fault(regs, address, SIGBUS);
 }
+
+#ifdef CONFIG_DEBUG_PAGEALLOC
+static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi)
+{
+        unsigned long hash, hpteg, vsid = get_kernel_vsid(vaddr);
+        unsigned long va = (vsid << 28) | (vaddr & 0x0fffffff);
+        unsigned long mode = _PAGE_ACCESSED | _PAGE_DIRTY |
+                _PAGE_COHERENT | PP_RWXX | HPTE_R_N;
+        int ret;
+
+        hash = hpt_hash(va, PAGE_SHIFT);
+        hpteg = ((hash & htab_hash_mask) * HPTES_PER_GROUP);
+
+        ret = ppc_md.hpte_insert(hpteg, va, __pa(vaddr),
+                                 mode, HPTE_V_BOLTED, mmu_linear_psize);
+        BUG_ON (ret < 0);
+        spin_lock(&linear_map_hash_lock);
+        BUG_ON(linear_map_hash_slots[lmi] & 0x80);
+        linear_map_hash_slots[lmi] = ret | 0x80;
+        spin_unlock(&linear_map_hash_lock);
+}
+
+static void kernel_unmap_linear_page(unsigned long vaddr, unsigned long lmi)
+{
+        unsigned long hash, hidx, slot, vsid = get_kernel_vsid(vaddr);
+        unsigned long va = (vsid << 28) | (vaddr & 0x0fffffff);
+
+        hash = hpt_hash(va, PAGE_SHIFT);
+        spin_lock(&linear_map_hash_lock);
+        BUG_ON(!(linear_map_hash_slots[lmi] & 0x80));
+        hidx = linear_map_hash_slots[lmi] & 0x7f;
+        linear_map_hash_slots[lmi] = 0;
+        spin_unlock(&linear_map_hash_lock);
+        if (hidx & _PTEIDX_SECONDARY)
+                hash = ~hash;
+        slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+        slot += hidx & _PTEIDX_GROUP_IX;
+        ppc_md.hpte_invalidate(slot, va, mmu_linear_psize, 0);
+}
+
+void kernel_map_pages(struct page *page, int numpages, int enable)
+{
+        unsigned long flags, vaddr, lmi;
+        int i;
+
+        local_irq_save(flags);
+        for (i = 0; i < numpages; i++, page++) {
+                vaddr = (unsigned long)page_address(page);
+                lmi = __pa(vaddr) >> PAGE_SHIFT;
+                if (lmi >= linear_map_hash_count)
+                        continue;
+                if (enable)
+                        kernel_map_linear_page(vaddr, lmi);
+                else
+                        kernel_unmap_linear_page(vaddr, lmi);
+        }
+        local_irq_restore(flags);
+}
+#endif /* CONFIG_DEBUG_PAGEALLOC */