Add statistics that show how memory is mapped within the kernel linear mapping.
This is similar to commit 37cd944c8d8f ("s390/pgtable: add mapping statistics")

We don't do this with Hash translation mode. Hash uses one size 
(mmu_linear_psize)
to map the kernel linear mapping and we print the linear psize during boot as
below.

"Page orders: linear mapping = 24, virtual = 16, io = 16, vmemmap = 24"

A sample output looks like:

DirectMap4k:           0 kB
DirectMap64k:       18432 kB
DirectMap2M:     1030144 kB
DirectMap1G:    11534336 kB

Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/pgalloc.h | 13 ++++++++++++
 arch/powerpc/include/asm/book3s/64/radix.h   |  3 +++
 arch/powerpc/mm/pgtable-book3s64.c           | 22 ++++++++++++++++++++
 arch/powerpc/mm/pgtable-radix.c              | 13 +++++++-----
 4 files changed, 46 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/pgalloc.h 
b/arch/powerpc/include/asm/book3s/64/pgalloc.h
index 01ee40f11f3a..1d2d69ae1bd2 100644
--- a/arch/powerpc/include/asm/book3s/64/pgalloc.h
+++ b/arch/powerpc/include/asm/book3s/64/pgalloc.h
@@ -208,4 +208,17 @@ static inline void __pte_free_tlb(struct mmu_gather *tlb, 
pgtable_t table,
 
 #define check_pgt_cache()      do { } while (0)
 
+extern atomic_long_t direct_pages_count[MMU_PAGE_COUNT];
+static inline void update_page_count(unsigned long mapping_shift, long count)
+{
+       int level;
+
+       if (IS_ENABLED(CONFIG_PROC_FS)) {
+               level = shift_to_mmu_psize(mapping_shift);
+               if (level < 0)
+                       return;
+               atomic_long_add(count, &direct_pages_count[level]);
+       }
+}
+
 #endif /* _ASM_POWERPC_BOOK3S_64_PGALLOC_H */
diff --git a/arch/powerpc/include/asm/book3s/64/radix.h 
b/arch/powerpc/include/asm/book3s/64/radix.h
index 3ab3f7aef022..56a6e3f5f7c1 100644
--- a/arch/powerpc/include/asm/book3s/64/radix.h
+++ b/arch/powerpc/include/asm/book3s/64/radix.h
@@ -30,6 +30,9 @@
 #define RADIX_PUD_BAD_BITS             0x60000000000000e0UL
 #define RADIX_PGD_BAD_BITS             0x60000000000000e0UL
 
+#define RADIX_PMD_SHIFT                (PAGE_SHIFT + RADIX_PTE_INDEX_SIZE)
+#define RADIX_PUD_SHIFT                (RADIX_PMD_SHIFT + RADIX_PMD_INDEX_SIZE)
+#define RADIX_PGD_SHIFT                (RADIX_PUD_SHIFT + RADIX_PUD_INDEX_SIZE)
 /*
  * Size of EA range mapped by our pagetables.
  */
diff --git a/arch/powerpc/mm/pgtable-book3s64.c 
b/arch/powerpc/mm/pgtable-book3s64.c
index 4afbfbb64bfd..5d2328ef7958 100644
--- a/arch/powerpc/mm/pgtable-book3s64.c
+++ b/arch/powerpc/mm/pgtable-book3s64.c
@@ -450,3 +450,25 @@ void pgtable_free_tlb(struct mmu_gather *tlb, void *table, 
int index)
        return pgtable_free(table, index);
 }
 #endif
+
+#ifdef CONFIG_PROC_FS
+atomic_long_t direct_pages_count[MMU_PAGE_COUNT];
+
+void arch_report_meminfo(struct seq_file *m)
+{
+       /*
+        * Hash maps the memory with one size mmu_linear_psize.
+        * So don't bother to print these on hash
+        */
+       if (!radix_enabled())
+               return;
+       seq_printf(m, "DirectMap4k:    %8lu kB\n",
+                  atomic_long_read(&direct_pages_count[MMU_PAGE_4K]) << 2);
+       seq_printf(m, "DirectMap64k:    %8lu kB\n",
+                  atomic_long_read(&direct_pages_count[MMU_PAGE_64K]) << 6);
+       seq_printf(m, "DirectMap2M:    %8lu kB\n",
+                  atomic_long_read(&direct_pages_count[MMU_PAGE_2M]) << 11);
+       seq_printf(m, "DirectMap1G:    %8lu kB\n",
+                  atomic_long_read(&direct_pages_count[MMU_PAGE_1G]) << 20);
+}
+#endif /* CONFIG_PROC_FS */
diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
index d9819e573103..5c5ca58e7d1f 100644
--- a/arch/powerpc/mm/pgtable-radix.c
+++ b/arch/powerpc/mm/pgtable-radix.c
@@ -259,6 +259,7 @@ static int __meminit create_physical_mapping(unsigned long 
start,
                                             unsigned long end,
                                             int nid)
 {
+       int mapping_shift;
        unsigned long vaddr, addr, mapping_size = 0;
        pgprot_t prot;
 #ifdef CONFIG_STRICT_KERNEL_RWX
@@ -277,18 +278,19 @@ static int __meminit create_physical_mapping(unsigned 
long start,
 
                if (IS_ALIGNED(addr, PUD_SIZE) && gap >= PUD_SIZE &&
                    mmu_psize_defs[MMU_PAGE_1G].shift)
-                       mapping_size = PUD_SIZE;
+                       mapping_shift = RADIX_PUD_SHIFT;
                else if (IS_ALIGNED(addr, PMD_SIZE) && gap >= PMD_SIZE &&
                         mmu_psize_defs[MMU_PAGE_2M].shift)
-                       mapping_size = PMD_SIZE;
+                       mapping_shift = RADIX_PMD_SHIFT;
                else
-                       mapping_size = PAGE_SIZE;
+                       mapping_shift = PAGE_SHIFT;
 
-               if (split_text_mapping && (mapping_size != PAGE_SIZE) &&
+               if (split_text_mapping && (mapping_shift != PAGE_SHIFT) &&
                    (addr <= __pa_symbol(__init_begin)) &&
                    (addr + mapping_size) >= __pa_symbol(_stext))
-                       mapping_size = PAGE_SIZE;
+                       mapping_shift = PAGE_SHIFT;
 
+               mapping_size = (1UL << mapping_shift);
                if (mapping_size != previous_size) {
                        print_mapping(start, addr, previous_size);
                        start = addr;
@@ -305,6 +307,7 @@ static int __meminit create_physical_mapping(unsigned long 
start,
                rc = __map_kernel_page(vaddr, addr, prot, mapping_size, nid, 
start, end);
                if (rc)
                        return rc;
+               update_page_count(mapping_shift, 1);
        }
 
        print_mapping(start, addr, mapping_size);
-- 
2.17.1

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