[POWERPC] Introduce lowmem_end_addr to distinguish from total_lowmem

total_lowmem represents the amount of low memory, not the physical
address that low memory ends at.  If the start of memory is at 0 it
happens that total_lowmem can be used as both the size and the address
that lowmem ends at (or more specifically one byte beyond the end).

To make the code a bit more clear and deal with the case when the start of
memory isn't at physical 0, we introduce lowmem_end_addr that represents
one byte beyond the last physical address in the lowmem region.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
index 1d7e5b8ade6a..ba61d088d2a2 100644
--- a/arch/powerpc/mm/init_32.c
+++ b/arch/powerpc/mm/init_32.c
@@ -146,6 +146,7 @@ void __init MMU_init(void)
         }
 
         total_lowmem = total_memory = lmb_end_of_DRAM() - memstart_addr;
+        lowmem_end_addr = memstart_addr + total_lowmem;
 
 #ifdef CONFIG_FSL_BOOKE
         /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
@@ -156,9 +157,10 @@ void __init MMU_init(void)
 
         if (total_lowmem > __max_low_memory) {
                 total_lowmem = __max_low_memory;
+                lowmem_end_addr = memstart_addr + total_lowmem;
 #ifndef CONFIG_HIGHMEM
                 total_memory = total_lowmem;
-                lmb_enforce_memory_limit(total_lowmem);
+                lmb_enforce_memory_limit(lowmem_end_addr);
                 lmb_analyze();
 #endif /* CONFIG_HIGHMEM */
         }