[PATCH] powerpc: mark pages that don't exist as nosave

Johannes Berg
2007-05-03T12:28:30Z

On some powerpc architectures (notably 64-bit powermac) there is a memory
hole, for example on powermacs between 2G and 4G. Since we use the flat
memory model regardless, these pages must be marked as nosave (for suspend
to disk.)

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>

---
Tested on powerbook and G5 powermac.

---
arch/powerpc/mm/mem.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)

--- wireless-dev.orig/arch/powerpc/mm/mem.c 2007-05-03 14:20:25.959165535 +0200
+++ wireless-dev/arch/powerpc/mm/mem.c 2007-05-03 14:21:09.659165535 +0200
@@ -31,6 +31,7 @@
#include <linux/highmem.h>
#include <linux/initrd.h>
#include <linux/pagemap.h>
+#include <linux/suspend.h>

#include <asm/pgalloc.h>
#include <asm/prom.h>
@@ -277,6 +278,28 @@ void __init do_init_bootmem(void)
init_bootmem_done = 1;
}

+/* mark pages that don't exist as nosave */
+static int __init mark_nonram_nosave(void)
+{
+ unsigned long lmb_next_region_start_pfn,
+ lmb_region_max_pfn;
+ int i;
+
+ for (i = 0; i < lmb.memory.cnt - 1; i++) {
+ lmb_region_max_pfn =
+ (lmb.memory.region[i].base >> PAGE_SHIFT) +
+ (lmb.memory.region[i].size >> PAGE_SHIFT);
+ lmb_next_region_start_pfn =
+ lmb.memory.region[i+1].base >> PAGE_SHIFT;
+
+ if (lmb_region_max_pfn < lmb_next_region_start_pfn)
+ register_nosave_region(lmb_region_max_pfn,
+ lmb_next_region_start_pfn);
+ }
+
+ return 0;
+}
+
/*
* paging_init() sets up the page tables - in fact we've already done this.
*/
@@ -308,6 +331,8 @@ void __init paging_init(void)
max_zone_pfns[ZONE_DMA] = top_of_ram >> PAGE_SHIFT;
#endif
free_area_init_nodes(max_zone_pfns);
+
+ mark_nonram_nosave();
}
#endif /* ! CONFIG_NEED_MULTIPLE_NODES */