The patch titled
memory hotplug: fix a bug on /dev/mem for 64-bit kernels
has been removed from the -mm tree. Its filename was
memory-hotplug-fix-a-bug-on-dev-mem-for-64-bit-kernels.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: memory hotplug: fix a bug on /dev/mem for 64-bit kernels
From: Shaohui Zheng <shaohui.zheng@xxxxxxxxx>
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@xxxxxxxxxxxxxxxxxxxx: simplify comment]
Signed-off-by: Shaohui Zheng <shaohui.zheng@xxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Li Haicheng <haicheng.li@xxxxxxxxx>
Reviewed-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/mm/init_64.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff -puN arch/x86/mm/init_64.c~memory-hotplug-fix-a-bug-on-dev-mem-for-64-bit-kernels arch/x86/mm/init_64.c
--- a/arch/x86/mm/init_64.c~memory-hotplug-fix-a-bug-on-dev-mem-for-64-bit-kernels
+++ a/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;
@@ -616,6 +617,21 @@ 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.
*/
@@ -634,6 +650,9 @@ int arch_add_memory(int nid, u64 start,
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);
_
Patches currently in -mm which might be from shaohui.zheng@xxxxxxxxx are
origin.patch
memory-hotplug-create-sys-firmware-memmap-entry-for-new-memory.patch
memory-hotplug-create-sys-firmware-memmap-entry-for-new-memory-fix.patch
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