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authorShaohui Zheng <shaohui.zheng@intel.com>2010-02-02 13:44:16 -0800
committerGreg Kroah-Hartman <gregkh@suse.de>2010-08-13 13:20:15 -0700
commit768cde06c7939b742603c52b26fccfbc65b308c2 (patch)
tree6c1fc2197df7222be3420bf60217e5fe4e90d59e
parent07049d16deb4ff91526619a471bdfb84b25db0d9 (diff)
memory hotplug: fix a bug on /dev/mem for 64-bit kernels
commit ea0854170c95245a258b386c7a9314399c949fe0 upstream. Newly added memory can not be accessed via /dev/mem, because we do not update the variables high_memory, max_pfn and max_low_pfn. Add a function update_end_of_memory_vars() to update these variables for 64-bit kernels. [akpm@linux-foundation.org: simplify comment] Signed-off-by: Shaohui Zheng <shaohui.zheng@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Li Haicheng <haicheng.li@intel.com> Reviewed-by: Wu Fengguang <fengguang.wu@intel.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--arch/x86/mm/init_64.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 5a4398a6006b..7d095ad54535 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -49,6 +49,7 @@
#include <asm/numa.h>
#include <asm/cacheflush.h>
#include <asm/init.h>
+#include <linux/bootmem.h>
static unsigned long dma_reserve __initdata;
@@ -615,6 +616,21 @@ void __init paging_init(void)
*/
#ifdef CONFIG_MEMORY_HOTPLUG
/*
+ * After memory hotplug the variables max_pfn, max_low_pfn and high_memory need
+ * updating.
+ */
+static void update_end_of_memory_vars(u64 start, u64 size)
+{
+ unsigned long end_pfn = PFN_UP(start + size);
+
+ if (end_pfn > max_pfn) {
+ max_pfn = end_pfn;
+ max_low_pfn = end_pfn;
+ high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;
+ }
+}
+
+/*
* Memory is added always to NORMAL zone. This means you will never get
* additional DMA/DMA32 memory.
*/
@@ -633,6 +649,9 @@ int arch_add_memory(int nid, u64 start, u64 size)
ret = __add_pages(nid, zone, start_pfn, nr_pages);
WARN_ON_ONCE(ret);
+ /* update max_pfn, max_low_pfn and high_memory */
+ update_end_of_memory_vars(start, size);
+
return ret;
}
EXPORT_SYMBOL_GPL(arch_add_memory);