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Date: Tue, 7 Jun 2011 19:24:13 +0200
From: Robert Richter <robert.richter@....com>
To: Ingo Molnar <mingo@...e.hu>, Peter Zijlstra <peterz@...radead.org>
CC: LKML <linux-kernel@...r.kernel.org>
Subject: [RFC] [PATCH] x86: Make copy_from_user_nmi() a library function
On 07.06.11 19:18:22, Robert Richter wrote:
> From c73bebe2e281ae089499d7cbc3b44a0869c8daf8 Mon Sep 17 00:00:00 2001
> From: Robert Richter <robert.richter@....com>
> Date: Fri, 3 Jun 2011 16:37:47 +0200
> Subject: [PATCH] oprofile, x86: Fix nmi-unsafe callgraph support
While this patch was a stable fix which introduced duplicate code for
perf and oprofile I suggest merging the code, see the patch below.
-Robert
>From 3652d1b07a0cfce5b26ad186594c1bf8f9ca5898 Mon Sep 17 00:00:00 2001
From: Robert Richter <robert.richter@....com>
Date: Tue, 7 Jun 2011 11:49:55 +0200
Subject: [PATCH] x86: 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@....com>
---
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
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index abd3e0e..c0236e9 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -556,6 +556,9 @@ 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 e638689..46bf36d 100644
--- 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>
@@ -43,40 +42,6 @@ do { \
} while (0)
#endif
-/*
- * 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
--- 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
index 0000000..4ef83d3
--- /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 assumes IRQ or NMI context
+ */
+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(copy_from_user_nmi);
diff --git a/arch/x86/oprofile/backtrace.c b/arch/x86/oprofile/backtrace.c
index 88e856e..087233f 100644
--- 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 void backtrace_warning_symbol(void *data, char *msg,
@@ -51,42 +50,6 @@ 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)
--
1.7.5.rc3
--
Advanced Micro Devices, Inc.
Operating System Research Center
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