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authorRobert Richter <robert.richter@amd.com>2011-06-07 13:49:55 +0400
committerIngo Molnar <mingo@elte.hu>2011-07-21 22:41:57 +0400
commit1ac2e6ca44e13a087eb7438d284f887097ee7e84 (patch)
tree7ee4f00a67850e1e247610cefeae0ee7aa7b239a /arch/x86/lib/usercopy.c
parent9985c20f9e4aee6857c08246b273a3695a52b929 (diff)
downloadlinux-1ac2e6ca44e13a087eb7438d284f887097ee7e84.tar.xz
x86, perf: Make copy_from_user_nmi() a library function
copy_from_user_nmi() is used in oprofile and perf. Moving it to other library functions like copy_from_user(). As this is x86 code for 32 and 64 bits, create a new file usercopy.c for unified code. Signed-off-by: Robert Richter <robert.richter@amd.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110607172413.GJ20052@erda.amd.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/lib/usercopy.c')
-rw-r--r--arch/x86/lib/usercopy.c43
1 files changed, 43 insertions, 0 deletions
diff --git a/arch/x86/lib/usercopy.c b/arch/x86/lib/usercopy.c
new file mode 100644
index 000000000000..97be9cb54483
--- /dev/null
+++ b/arch/x86/lib/usercopy.c
@@ -0,0 +1,43 @@
+/*
+ * User address space access functions.
+ *
+ * For licencing details see kernel-base/COPYING
+ */
+
+#include <linux/highmem.h>
+#include <linux/module.h>
+
+/*
+ * best effort, GUP based copy_from_user() that is NMI-safe
+ */
+unsigned long
+copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
+{
+ unsigned long offset, addr = (unsigned long)from;
+ unsigned long size, len = 0;
+ struct page *page;
+ void *map;
+ int ret;
+
+ do {
+ ret = __get_user_pages_fast(addr, 1, 0, &page);
+ if (!ret)
+ break;
+
+ offset = addr & (PAGE_SIZE - 1);
+ size = min(PAGE_SIZE - offset, n - len);
+
+ map = kmap_atomic(page);
+ memcpy(to, map+offset, size);
+ kunmap_atomic(map);
+ put_page(page);
+
+ len += size;
+ to += size;
+ addr += size;
+
+ } while (len < n);
+
+ return len;
+}
+EXPORT_SYMBOL_GPL(copy_from_user_nmi);