From a99824f327c748b2753f4fa570eb1fefcd6a9c4d Mon Sep 17 00:00:00 2001
From: Badari Pulavarty <pbadari@us.ibm.com>
Date: Tue, 5 Feb 2008 00:10:18 -0800
Subject: [PATCH] [POWERPC] Add arch-specific walk_memory_remove() for 64-bit
powerpc
walk_memory_resource() verifies if there are holes in a given memory
range, by checking against /proc/iomem. On x86/ia64 system memory is
represented in /proc/iomem. On powerpc, we don't show system memory as
IO resource in /proc/iomem - instead it's maintained in
/proc/device-tree.
This provides a way for an architecture to provide its own
walk_memory_resource() function. On powerpc, the memory region is
small (16MB), contiguous and non-overlapping. So extra checking
against the device-tree is not needed.
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@gate.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
---
arch/powerpc/Kconfig | 3 +++
arch/powerpc/mm/mem.c | 17 +++++++++++++++++
kernel/resource.c | 2 +-
3 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index d55063c021d53..26b963c33c88d 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -272,6 +272,9 @@ config HOTPLUG_CPU
config ARCH_ENABLE_MEMORY_HOTPLUG
def_bool y
+config ARCH_HAS_WALK_MEMORY
+ def_bool y
+
config ARCH_ENABLE_MEMORY_HOTREMOVE
def_bool y
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index f0a1fd268b7a3..be5c506779a74 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -145,6 +145,23 @@ out:
return ret;
}
#endif /* CONFIG_MEMORY_HOTREMOVE */
+
+/*
+ * walk_memory_resource() needs to make sure there is no holes in a given
+ * memory range. On PPC64, since this range comes from /sysfs, the range
+ * is guaranteed to be valid, non-overlapping and can not contain any
+ * holes. By the time we get here (memory add or remove), /proc/device-tree
+ * is updated and correct. Only reason we need to check against device-tree
+ * would be if we allow user-land to specify a memory range through a
+ * system call/ioctl etc. instead of doing offline/online through /sysfs.
+ */
+int
+walk_memory_resource(unsigned long start_pfn, unsigned long nr_pages, void *arg,
+ int (*func)(unsigned long, unsigned long, void *))
+{
+ return (*func)(start_pfn, nr_pages, arg);
+}
+
#endif /* CONFIG_MEMORY_HOTPLUG */
void show_mem(void)
diff --git a/kernel/resource.c b/kernel/resource.c
index 2eb553d9b5171..82aea814d4097 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -228,7 +228,7 @@ int release_resource(struct resource *old)
EXPORT_SYMBOL(release_resource);
-#ifdef CONFIG_MEMORY_HOTPLUG
+#if defined(CONFIG_MEMORY_HOTPLUG) && !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
/*
* Finds the lowest memory reosurce exists within [res->start.res->end)
* the caller must specify res->start, res->end, res->flags.
--
2.30.2