forked from Minki/linux
0a196848ca
The arch_perf_output_copy_user() default of
__copy_from_user_inatomic() returns bytes not copied, while all other
argument functions given DEFINE_OUTPUT_COPY() return bytes copied.
Since copy_from_user_nmi() is the odd duck out by returning bytes
copied where all other *copy_{to,from}* functions return bytes not
copied, change it over and ammend DEFINE_OUTPUT_COPY() to expect bytes
not copied.
Oddly enough DEFINE_OUTPUT_COPY() already returned bytes not copied
while expecting its worker functions to return bytes copied.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: will.deacon@arm.com
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20131030201622.GR16117@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
37 lines
837 B
C
37 lines
837 B
C
/*
|
|
* User address space access functions.
|
|
*
|
|
* For licencing details see kernel-base/COPYING
|
|
*/
|
|
|
|
#include <linux/highmem.h>
|
|
#include <linux/module.h>
|
|
|
|
#include <asm/word-at-a-time.h>
|
|
#include <linux/sched.h>
|
|
|
|
/*
|
|
* We rely on the nested NMI work to allow atomic faults from the NMI path; the
|
|
* nested NMI paths are careful to preserve CR2.
|
|
*/
|
|
unsigned long
|
|
copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
|
|
{
|
|
unsigned long ret;
|
|
|
|
if (__range_not_ok(from, n, TASK_SIZE))
|
|
return 0;
|
|
|
|
/*
|
|
* Even though this function is typically called from NMI/IRQ context
|
|
* disable pagefaults so that its behaviour is consistent even when
|
|
* called form other contexts.
|
|
*/
|
|
pagefault_disable();
|
|
ret = __copy_from_user_inatomic(to, from, n);
|
|
pagefault_enable();
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(copy_from_user_nmi);
|