ARM: Fix sparsemem with SPARSEMEM_EXTREME enabled

When SPARSEMEM_EXTREME is enabled, memory_present() wants to use bootmem
to allocate data structures.  However, we call memory_present() after
declaring memory to bootmem, but before we've reserved areas.

This leads to sparsemem data structures being overwritten later in the
kernel's initialization (when slab initializes.)

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 19 insertions, 1 deletions

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 40940d7ce4ff..52c40d155672 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -273,7 +273,6 @@ static void __init bootmem_init_node(int node, struct meminfo *mi,
                 struct membank *bank = &mi->bank[i];
                 if (!bank->highmem)
                         free_bootmem_node(pgdat, bank_phys_start(bank), bank_phys_size(bank));
-                memory_present(node, bank_pfn_start(bank), bank_pfn_end(bank));
         }
 
         /*
@@ -370,6 +369,19 @@ int pfn_valid(unsigned long pfn)
         return 0;
 }
 EXPORT_SYMBOL(pfn_valid);
+
+static void arm_memory_present(struct meminfo *mi, int node)
+{
+}
+#else
+static void arm_memory_present(struct meminfo *mi, int node)
+{
+        int i;
+        for_each_nodebank(i, mi, node) {
+                struct membank *bank = &mi->bank[i];
+                memory_present(node, bank_pfn_start(bank), bank_pfn_end(bank));
+        }
+}
 #endif
 
 static int __init meminfo_cmp(const void *_a, const void *_b)
@@ -427,6 +439,12 @@ void __init bootmem_init(void)
                  */
                 if (node == initrd_node)
                         bootmem_reserve_initrd(node);
+
+                /*
+                 * Sparsemem tries to allocate bootmem in memory_present(),
+                 * so must be done after the fixed reservations
+                 */
+                arm_memory_present(mi, node);
         }
 
         /*