Re: [RFC] [PATCH] x86: Make copy_from_user_nmi() a library function
From: Peter Zijlstra
Date: Tue Jul 05 2011 - 13:40:17 EST
On Tue, 2011-07-05 at 19:22 +0200, Robert Richter wrote:
> Ingo, Peter,
>
> what about this patch? Any opinion? This one should be against
> tip/perf/core now.
Ah, thanks for the reminder, yeah, took it with EXPORT_SYMBOL_GPL.
---
Subject: x86: Make copy_from_user_nmi() a library function
From: Robert Richter <robert.richter@xxxxxxx>
Date: Tue, 7 Jun 2011 11:49:55 +0200
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@xxxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/r/20110607172413.GJ20052@xxxxxxxxxxxx
---
arch/x86/include/asm/uaccess.h | 3 ++
arch/x86/kernel/cpu/perf_event.c | 35 -------------------------------
arch/x86/lib/Makefile | 2 -
arch/x86/lib/usercopy.c | 43 +++++++++++++++++++++++++++++++++++++++
arch/x86/oprofile/backtrace.c | 39 -----------------------------------
5 files changed, 48 insertions(+), 74 deletions(-)
create mode 100644 arch/x86/lib/usercopy.c
Index: linux-2.6/arch/x86/include/asm/uaccess.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/uaccess.h
+++ linux-2.6/arch/x86/include/asm/uaccess.h
@@ -555,6 +555,9 @@ struct __large_struct { unsigned long bu
#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
*/
Index: linux-2.6/arch/x86/kernel/cpu/perf_event.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event.c
+++ linux-2.6/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)];
Index: linux-2.6/arch/x86/lib/Makefile
===================================================================
--- linux-2.6.orig/arch/x86/lib/Makefile
+++ linux-2.6/arch/x86/lib/Makefile
@@ -18,7 +18,7 @@ obj-$(CONFIG_SMP) += msr-smp.o cache-smp
lib-y := delay.o
lib-y += thunk_$(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
Index: linux-2.6/arch/x86/lib/usercopy.c
===================================================================
--- /dev/null
+++ linux-2.6/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);
Index: linux-2.6/arch/x86/oprofile/backtrace.c
===================================================================
--- linux-2.6.orig/arch/x86/oprofile/backtrace.c
+++ linux-2.6/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_o
.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)
--
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