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Commit 6144a85a authored by Jason Wessel's avatar Jason Wessel
Browse files

maccess,probe_kernel: Allow arch specific override probe_kernel_(read|write) 



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: default avatarJason Wessel <jason.wessel@windriver.com>
Signed-off-by: default avatarMike Frysinger <vapier@gentoo.org>
parent 2c1f1895

include/linux/uaccess.h

+3 −1
Original line number Diff line number Diff line
@@ -94,6 +94,7 @@ static inline unsigned long __copy_from_user_nocache(void *to, 
 * happens, handle that and return -EFAULT.

 */

extern long probe_kernel_read(void *dst, void *src, size_t size);

extern long __probe_kernel_read(void *dst, void *src, size_t size);



/*

 * probe_kernel_write(): safely attempt to write to a location
@@ -104,6 +105,7 @@ extern long probe_kernel_read(void *dst, void *src, size_t size); 
 * Safely write to address @dst from the buffer at @src.  If a kernel fault

 * happens, handle that and return -EFAULT.

 */

extern long probe_kernel_write(void *dst, void *src, size_t size);

extern long notrace probe_kernel_write(void *dst, void *src, size_t size);

extern long notrace __probe_kernel_write(void *dst, void *src, size_t size);



#endif		/* __LINUX_UACCESS_H__ */

mm/maccess.c

+9 −2
Original line number Diff line number Diff line
@@ -14,7 +14,11 @@ 
 * Safely read from address @src to the buffer at @dst.  If a kernel fault

 * happens, handle that and return -EFAULT.

 */

long probe_kernel_read(void *dst, void *src, size_t size)



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();
@@ -39,7 +43,10 @@ EXPORT_SYMBOL_GPL(probe_kernel_read); 
 * Safely write to address @dst from the buffer at @src.  If a kernel fault

 * happens, handle that and return -EFAULT.

 */

long notrace __weak probe_kernel_write(void *dst, void *src, size_t size)

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();