Make MAX_PHYSMEM_BITS and SECTIONS_SIZE_BITS configurable by adding
config options.
Default to current settings currently defined in sparesmem.h.
For systems wishing to save memory the config options can be overridden.
Example, changing MAX_PHYSMEM_BITS from 48 to 36 at the same time as
changing SECTION_SIZE_BITS from 30 to 26 frees 13MB of memory.
Signed-off-by: Scott Branden <scott.bran...@broadcom.com>
---
arch/arm64/Kconfig | 21 +++++++++++++++++++++
arch/arm64/include/asm/sparsemem.h | 4 ++--
2 files changed, 23 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 2482fdd..d0a95de 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -121,6 +121,27 @@ config ARCH_PHYS_ADDR_T_64BIT
config MMU
def_bool y
+config MAX_PHYSMEM_BITS
+ int "Maximum Physical Addressable Bits"
+ depends on SPARSEMEM
+ default 48
+ help
+ Maximum number of physical addressable bits.
+ If not all the physical bits are used this number can be reduced
+ to save memory when creating page tables.
+
+ If unsure, leave this at the default.
+
+config SECTION_SIZE_BITS
+ int "Section Size Bits"
+ depends on SPARSEMEM
+ default 30
+ help
+ Size of each memory section.
+ If you need to be able to allocate smaller
+ sections in page table this number can be change to save memory.
+
+ If unsure, leave this at the default.
config DEBUG_RODATA
def_bool y
diff --git a/arch/arm64/include/asm/sparsemem.h
b/arch/arm64/include/asm/sparsemem.h
index 74a9d30..6677582 100644
--- a/arch/arm64/include/asm/sparsemem.h
+++ b/arch/arm64/include/asm/sparsemem.h
@@ -17,8 +17,8 @@
#define __ASM_SPARSEMEM_H
#ifdef CONFIG_SPARSEMEM
-#define MAX_PHYSMEM_BITS 48
-#define SECTION_SIZE_BITS 30
+#define MAX_PHYSMEM_BITS CONFIG_MAX_PHYSMEM_BITS
+#define SECTION_SIZE_BITS CONFIG_SECTION_SIZE_BITS
#endif
#endif
--
2.5.0
