mirror of
https://github.com/torvalds/linux.git
synced 2024-12-22 10:56:40 +00:00
6144a85a0e
Some archs such as blackfin, would like to have an arch specific probe_kernel_read() and probe_kernel_write() implementation which can fall back to the generic implementation if no special operations are needed. CC: Thomas Gleixner <tglx@linutronix.de> CC: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Mike Frysinger <vapier@gentoo.org>
63 lines
1.6 KiB
C
63 lines
1.6 KiB
C
/*
|
|
* Access kernel memory without faulting.
|
|
*/
|
|
#include <linux/uaccess.h>
|
|
#include <linux/module.h>
|
|
#include <linux/mm.h>
|
|
|
|
/**
|
|
* probe_kernel_read(): safely attempt to read from a location
|
|
* @dst: pointer to the buffer that shall take the data
|
|
* @src: address to read from
|
|
* @size: size of the data chunk
|
|
*
|
|
* Safely read from address @src to the buffer at @dst. If a kernel fault
|
|
* happens, handle that and return -EFAULT.
|
|
*/
|
|
|
|
long __weak probe_kernel_read(void *dst, void *src, size_t size)
|
|
__attribute__((alias("__probe_kernel_read")));
|
|
|
|
long __probe_kernel_read(void *dst, void *src, size_t size)
|
|
{
|
|
long ret;
|
|
mm_segment_t old_fs = get_fs();
|
|
|
|
set_fs(KERNEL_DS);
|
|
pagefault_disable();
|
|
ret = __copy_from_user_inatomic(dst,
|
|
(__force const void __user *)src, size);
|
|
pagefault_enable();
|
|
set_fs(old_fs);
|
|
|
|
return ret ? -EFAULT : 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(probe_kernel_read);
|
|
|
|
/**
|
|
* probe_kernel_write(): safely attempt to write to a location
|
|
* @dst: address to write to
|
|
* @src: pointer to the data that shall be written
|
|
* @size: size of the data chunk
|
|
*
|
|
* Safely write to address @dst from the buffer at @src. If a kernel fault
|
|
* happens, handle that and return -EFAULT.
|
|
*/
|
|
long __weak probe_kernel_write(void *dst, void *src, size_t size)
|
|
__attribute__((alias("__probe_kernel_write")));
|
|
|
|
long __probe_kernel_write(void *dst, void *src, size_t size)
|
|
{
|
|
long ret;
|
|
mm_segment_t old_fs = get_fs();
|
|
|
|
set_fs(KERNEL_DS);
|
|
pagefault_disable();
|
|
ret = __copy_to_user_inatomic((__force void __user *)dst, src, size);
|
|
pagefault_enable();
|
|
set_fs(old_fs);
|
|
|
|
return ret ? -EFAULT : 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(probe_kernel_write);
|