mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-30 16:13:54 +08:00
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>
112 lines
3.3 KiB
C
112 lines
3.3 KiB
C
#ifndef __LINUX_UACCESS_H__
|
|
#define __LINUX_UACCESS_H__
|
|
|
|
#include <linux/preempt.h>
|
|
#include <asm/uaccess.h>
|
|
|
|
/*
|
|
* These routines enable/disable the pagefault handler in that
|
|
* it will not take any locks and go straight to the fixup table.
|
|
*
|
|
* They have great resemblance to the preempt_disable/enable calls
|
|
* and in fact they are identical; this is because currently there is
|
|
* no other way to make the pagefault handlers do this. So we do
|
|
* disable preemption but we don't necessarily care about that.
|
|
*/
|
|
static inline void pagefault_disable(void)
|
|
{
|
|
inc_preempt_count();
|
|
/*
|
|
* make sure to have issued the store before a pagefault
|
|
* can hit.
|
|
*/
|
|
barrier();
|
|
}
|
|
|
|
static inline void pagefault_enable(void)
|
|
{
|
|
/*
|
|
* make sure to issue those last loads/stores before enabling
|
|
* the pagefault handler again.
|
|
*/
|
|
barrier();
|
|
dec_preempt_count();
|
|
/*
|
|
* make sure we do..
|
|
*/
|
|
barrier();
|
|
preempt_check_resched();
|
|
}
|
|
|
|
#ifndef ARCH_HAS_NOCACHE_UACCESS
|
|
|
|
static inline unsigned long __copy_from_user_inatomic_nocache(void *to,
|
|
const void __user *from, unsigned long n)
|
|
{
|
|
return __copy_from_user_inatomic(to, from, n);
|
|
}
|
|
|
|
static inline unsigned long __copy_from_user_nocache(void *to,
|
|
const void __user *from, unsigned long n)
|
|
{
|
|
return __copy_from_user(to, from, n);
|
|
}
|
|
|
|
#endif /* ARCH_HAS_NOCACHE_UACCESS */
|
|
|
|
/**
|
|
* probe_kernel_address(): safely attempt to read from a location
|
|
* @addr: address to read from - its type is type typeof(retval)*
|
|
* @retval: read into this variable
|
|
*
|
|
* Safely read from address @addr into variable @revtal. If a kernel fault
|
|
* happens, handle that and return -EFAULT.
|
|
* We ensure that the __get_user() is executed in atomic context so that
|
|
* do_page_fault() doesn't attempt to take mmap_sem. This makes
|
|
* probe_kernel_address() suitable for use within regions where the caller
|
|
* already holds mmap_sem, or other locks which nest inside mmap_sem.
|
|
* This must be a macro because __get_user() needs to know the types of the
|
|
* args.
|
|
*
|
|
* We don't include enough header files to be able to do the set_fs(). We
|
|
* require that the probe_kernel_address() caller will do that.
|
|
*/
|
|
#define probe_kernel_address(addr, retval) \
|
|
({ \
|
|
long ret; \
|
|
mm_segment_t old_fs = get_fs(); \
|
|
\
|
|
set_fs(KERNEL_DS); \
|
|
pagefault_disable(); \
|
|
ret = __copy_from_user_inatomic(&(retval), (__force typeof(retval) __user *)(addr), sizeof(retval)); \
|
|
pagefault_enable(); \
|
|
set_fs(old_fs); \
|
|
ret; \
|
|
})
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
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
|
|
* @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.
|
|
*/
|
|
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__ */
|