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x86, perf: Make copy_from_user_nmi() a library function

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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>
This commit is contained in:
Robert Richter 2011-06-07 11:49:55 +02:00 committed by Ingo Molnar
parent 9985c20f9e
commit 1ac2e6ca44
5 changed files with 48 additions and 74 deletions
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3
arch/x86/include/asm/uaccess.h
View file

@ -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
*/

35
arch/x86/kernel/cpu/perf_event.c
View file

@ -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)];

2
arch/x86/lib/Makefile
View file

@ -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

43
arch/x86/lib/usercopy.c Normal file
View file

@ -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);

39
arch/x86/oprofile/backtrace.c
View file

@ -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)