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-rw-r--r--arch/powerpc/mm/40x_mmu.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/arch/powerpc/mm/40x_mmu.c b/arch/powerpc/mm/40x_mmu.c
index cecbbc76f624..29954dc28942 100644
--- a/arch/powerpc/mm/40x_mmu.c
+++ b/arch/powerpc/mm/40x_mmu.c
@@ -93,7 +93,7 @@ void __init MMU_init_hw(void)
unsigned long __init mmu_mapin_ram(void)
{
- unsigned long v, s;
+ unsigned long v, s, mapped;
phys_addr_t p;
v = KERNELBASE;
@@ -130,5 +130,17 @@ unsigned long __init mmu_mapin_ram(void)
s -= LARGE_PAGE_SIZE_4M;
}
- return total_lowmem - s;
+ mapped = total_lowmem - s;
+
+ /* If the size of RAM is not an exact power of two, we may not
+ * have covered RAM in its entirety with 16 and 4 MiB
+ * pages. Consequently, restrict the top end of RAM currently
+ * allocable so that calls to the LMB to allocate PTEs for "tail"
+ * coverage with normal-sized pages (or other reasons) do not
+ * attempt to allocate outside the allowed range.
+ */
+
+ __initial_memory_limit_addr = memstart_addr + mapped;
+
+ return mapped;
}