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>

diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 99ddd14..36361bf 100644 (file)
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -555,6 +555,9 @@ struct __large_struct { unsigned long buf[100]; };
 
 #endif /* CONFIG_X86_WP_WORKS_OK */
 
+extern unsigned long
+copy_from_user_nmi(void *to, const void __user *from, unsigned long n);
+
 /*
  * movsl can be slow when source and dest are not both 8-byte aligned
  */

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index b7a010f..4ee3abf 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -22,7 +22,6 @@
 #include <linux/sched.h>
 #include <linux/uaccess.h>
 #include <linux/slab.h>
-#include <linux/highmem.h>
 #include <linux/cpu.h>
 #include <linux/bitops.h>
 
@@ -67,40 +66,6 @@ enum extra_reg_type {
        EXTRA_REG_MAX           /* number of entries needed */
 };
 
-/*
- * best effort, GUP based copy_from_user() that assumes IRQ or NMI context
- */
-static 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;
-}
-
 struct event_constraint {
        union {
                unsigned long   idxmsk[BITS_TO_LONGS(X86_PMC_IDX_MAX)];

diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index f2479f1..6ba4773 100644 (file)
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -18,7 +18,7 @@ obj-$(CONFIG_SMP) += msr-smp.o cache-smp.o
 
 lib-y := delay.o
 lib-y += thunk_$(BITS).o
-lib-y += usercopy_$(BITS).o getuser.o putuser.o
+lib-y += usercopy_$(BITS).o usercopy.o getuser.o putuser.o
 lib-y += memcpy_$(BITS).o
 lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o
 

diff --git a/arch/x86/lib/usercopy.c b/arch/x86/lib/usercopy.c
new file mode 100644 (file)
index 0000000..97be9cb
--- /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);

diff --git a/arch/x86/oprofile/backtrace.c b/arch/x86/oprofile/backtrace.c
index 32f78eb..bff89df 100644 (file)
--- a/arch/x86/oprofile/backtrace.c
+++ b/arch/x86/oprofile/backtrace.c
@@ -12,10 +12,9 @@
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/compat.h>
-#include <linux/highmem.h>
+#include <linux/uaccess.h>
 
 #include <asm/ptrace.h>
-#include <asm/uaccess.h>
 #include <asm/stacktrace.h>
 
 static int backtrace_stack(void *data, char *name)
@@ -38,42 +37,6 @@ static struct stacktrace_ops backtrace_ops = {
        .walk_stack     = print_context_stack,
 };
 
-/* from arch/x86/kernel/cpu/perf_event.c: */
-
-/*
- * best effort, GUP based copy_from_user() that assumes IRQ or NMI context
- */
-static 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;
-}
-
 #ifdef CONFIG_COMPAT
 static struct stack_frame_ia32 *
 dump_user_backtrace_32(struct stack_frame_ia32 *head)