xtensa: add alternative kernel memory layouts

MMUv3 is able to support low memory bigger than 128MB.
Implement 256MB and 512MB KSEG layouts:

- add Kconfig selector for KSEG layout;
- add KSEG base address, size and alignment definitions to
  arch/xtensa/include/asm/kmem_layout.h;
- use new definitions in TLB initialization;
- add build time memory map consistency checks.

See Documentation/xtensa/mmu.txt for the details of new memory layouts.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/arch/xtensa/mm/init.c b/arch/xtensa/mm/init.c
index 4d7142beac72..302fa72d0d5a 100644
--- a/arch/xtensa/mm/init.c
+++ b/arch/xtensa/mm/init.c
@@ -266,8 +266,7 @@ void __init bootmem_init(void)
         if (min_low_pfn > max_pfn)
                 panic("No memory found!\n");
 
-        max_low_pfn = max_pfn < MAX_MEM_PFN >> PAGE_SHIFT ?
-                max_pfn : MAX_MEM_PFN >> PAGE_SHIFT;
+        max_low_pfn = min(max_pfn, MAX_LOW_PFN);
 
         /* Find an area to use for the bootmem bitmap. */