arch/arm/include/asm/uaccess.h

Source file repositories/reference/linux-study-clean/arch/arm/include/asm/uaccess.h

File Facts

System
Linux kernel
Corpus path
arch/arm/include/asm/uaccess.h
Extension
.h
Size
18046 bytes
Lines
634
Domain
Architecture Layer
Bucket
arch/arm
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

switch (sizeof(*(__p))) {				\
		case 1:							\
			if (sizeof((x)) >= 8)				\
				__get_user_x_64t(__r2, __p, __e, __l, 1); \
			else						\
				__get_user_x(__r2, __p, __e, __l, 1);	\
			break;						\
		case 2:							\
			if (sizeof((x)) >= 8)				\
				__get_user_x_64t(__r2, __p, __e, __l, 2); \
			else						\
				__get_user_x(__r2, __p, __e, __l, 2);	\
			break;						\
		case 4:							\
			if (sizeof((x)) >= 8)				\
				__get_user_x_64t(__r2, __p, __e, __l, 4); \
			else						\
				__get_user_x(__r2, __p, __e, __l, 4);	\
			break;						\
		case 8:							\
			if (sizeof((x)) < 8)				\
				__get_user_x_32t(__r2, __p, __e, __l, 4); \
			else						\
				__get_user_x(__r2, __p, __e, __l, 8);	\
			break;						\
		default: __e = __get_user_bad(); break;			\
		}							\
		__tmp_e = __e;						\
		uaccess_restore(__ua_flags);				\
		x = (typeof(*(p))) __r2;				\
		__tmp_e;						\
	})

#define get_user(x, p)							\
	({								\
		might_fault();						\
		__get_user_check(x, p);					\
	 })

extern int __put_user_1(void *, unsigned int);
extern int __put_user_2(void *, unsigned int);
extern int __put_user_4(void *, unsigned int);
extern int __put_user_8(void *, unsigned long long);

#define __put_user_check(__pu_val, __ptr, __err, __s)			\
	({								\
		unsigned long __limit = TASK_SIZE - 1; \
		register typeof(__pu_val) __r2 asm("r2") = __pu_val;	\
		register const void __user *__p asm("r0") = __ptr;	\
		register unsigned long __l asm("r1") = __limit;		\
		register int __e asm("r0");				\
		__asm__ __volatile__ (					\
			__asmeq("%0", "r0") __asmeq("%2", "r2")		\
			__asmeq("%3", "r1")				\
			"bl	__put_user_" #__s			\
			: "=&r" (__e)					\
			: "0" (__p), "r" (__r2), "r" (__l)		\
			: "ip", "lr", "cc");				\
		__err = __e;						\
	})

#else /* CONFIG_MMU */

#define get_user(x, p)	__get_user(x, p)
#define __put_user_check __put_user_nocheck

#endif /* CONFIG_MMU */

#include <asm-generic/access_ok.h>

#ifdef CONFIG_CPU_SPECTRE
/*
 * When mitigating Spectre variant 1, it is not worth fixing the non-
 * verifying accessors, because we need to add verification of the
 * address space there.  Force these to use the standard get_user()
 * version instead.
 */
#define __get_user(x, ptr) get_user(x, ptr)
#else

/*
 * The "__xxx" versions of the user access functions do not verify the
 * address space - it must have been done previously with a separate
 * "access_ok()" call.
 *
 * The "xxx_error" versions set the third argument to EFAULT if an
 * error occurs, and leave it unchanged on success.  Note that these
 * versions are void (ie, don't return a value as such).
 */
#define __get_user(x, ptr)						\

Annotation

Implementation Notes