RISC-V: Implement sparsemem

[linux-2.6-microblaze.git] / arch / riscv / include / asm / pgtable.h

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index a364aba..80905b2 100644 (file)
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -83,6 +83,19 @@ extern pgd_t swapper_pg_dir[];
 #define __S110 PAGE_SHARED_EXEC
 #define __S111 PAGE_SHARED_EXEC
 
+/*
+ * Roughly size the vmemmap space to be large enough to fit enough
+ * struct pages to map half the virtual address space. Then
+ * position vmemmap directly below the VMALLOC region.
+ */
+#define VMEMMAP_SHIFT \
+       (CONFIG_VA_BITS - PAGE_SHIFT - 1 + STRUCT_PAGE_MAX_SHIFT)
+#define VMEMMAP_SIZE   BIT(VMEMMAP_SHIFT)
+#define VMEMMAP_END    (VMALLOC_START - 1)
+#define VMEMMAP_START  (VMALLOC_START - VMEMMAP_SIZE)
+
+#define vmemmap                ((struct page *)VMEMMAP_START)
+
 /*
  * ZERO_PAGE is a global shared page that is always zero,
  * used for zero-mapped memory areas, etc.
@@ -420,14 +433,22 @@ static inline void pgtable_cache_init(void)
 #define VMALLOC_END      (PAGE_OFFSET - 1)
 #define VMALLOC_START    (PAGE_OFFSET - VMALLOC_SIZE)
 
+#define FIXADDR_TOP      VMALLOC_START
+#ifdef CONFIG_64BIT
+#define FIXADDR_SIZE     PMD_SIZE
+#else
+#define FIXADDR_SIZE     PGDIR_SIZE
+#endif
+#define FIXADDR_START    (FIXADDR_TOP - FIXADDR_SIZE)
+
 /*
- * Task size is 0x4000000000 for RV64 or 0xb800000 for RV32.
+ * Task size is 0x4000000000 for RV64 or 0x9fc00000 for RV32.
  * Note that PGDIR_SIZE must evenly divide TASK_SIZE.
  */
 #ifdef CONFIG_64BIT
 #define TASK_SIZE (PGDIR_SIZE * PTRS_PER_PGD / 2)
 #else
-#define TASK_SIZE VMALLOC_START
+#define TASK_SIZE FIXADDR_START
 #endif
 
 #include <asm-generic/pgtable.h>