[v2,01/10] riscv: Allow to dynamically define VA_BITS

Commit Message

Alexandre Ghiti Sept. 29, 2021, 2:51 p.m. UTC

With 4-level page table folding at runtime, we don't know at compile time
the size of the virtual address space so we must set VA_BITS dynamically
so that sparsemem reserves the right amount of memory for struct pages.

Signed-off-by: Alexandre Ghiti <[e-mail]>
---
 arch/riscv/Kconfig                 | 10 ----------
 arch/riscv/include/asm/pgtable.h   | 10 ++++++++--
 arch/riscv/include/asm/sparsemem.h |  6 +++++-
 3 files changed, 13 insertions(+), 13 deletions(-)

Patch

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index c1abbc876e5b..ee61ecae3ae0 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -145,16 +145,6 @@  config MMU
 	  Select if you want MMU-based virtualised addressing space
 	  support by paged memory management. If unsure, say 'Y'.
 
-config VA_BITS
-	int
-	default 32 if 32BIT
-	default 39 if 64BIT
-
-config PA_BITS
-	int
-	default 34 if 32BIT
-	default 56 if 64BIT
-
 config PAGE_OFFSET
 	hex
 	default 0xC0000000 if 32BIT && MAXPHYSMEM_1GB
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 39b550310ec6..e3e03226a50a 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -48,8 +48,14 @@ 
  * struct pages to map half the virtual address space. Then
  * position vmemmap directly below the VMALLOC region.
  */
+#ifdef CONFIG_64BIT
+#define VA_BITS		39
+#else
+#define VA_BITS		32
+#endif
+
 #define VMEMMAP_SHIFT \
-	(CONFIG_VA_BITS - PAGE_SHIFT - 1 + STRUCT_PAGE_MAX_SHIFT)
+	(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)
@@ -651,7 +657,7 @@  static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
  * and give the kernel the other (upper) half.
  */
 #ifdef CONFIG_64BIT
-#define KERN_VIRT_START	(-(BIT(CONFIG_VA_BITS)) + TASK_SIZE)
+#define KERN_VIRT_START	(-(BIT(VA_BITS)) + TASK_SIZE)
 #else
 #define KERN_VIRT_START	FIXADDR_START
 #endif
diff --git a/arch/riscv/include/asm/sparsemem.h b/arch/riscv/include/asm/sparsemem.h
index 45a7018a8118..63acaecc3374 100644
--- a/arch/riscv/include/asm/sparsemem.h
+++ b/arch/riscv/include/asm/sparsemem.h
@@ -4,7 +4,11 @@ 
 #define _ASM_RISCV_SPARSEMEM_H
 
 #ifdef CONFIG_SPARSEMEM
-#define MAX_PHYSMEM_BITS	CONFIG_PA_BITS
+#ifdef CONFIG_64BIT
+#define MAX_PHYSMEM_BITS	56
+#else
+#define MAX_PHYSMEM_BITS	34
+#endif /* CONFIG_64BIT */
 #define SECTION_SIZE_BITS	27
 #endif /* CONFIG_SPARSEMEM */