riscv: remove address space overrides using set_fs()

	select SPARSE_IRQ

	select SYSCTL_EXCEPTION_TRACE

	select THREAD_INFO_IN_TASK

	select SET_FS

	select UACCESS_MEMCPY if !MMU

config ARCH_MMAP_RND_BITS_MIN

#include <asm/processor.h>

#include <asm/csr.h>

typedef struct {

	unsigned long seg;

} mm_segment_t;

/*

 * low level task data that entry.S needs immediate access to

 * - this struct should fit entirely inside of one cache line

struct thread_info {

	unsigned long		flags;		/* low level flags */

	int                     preempt_count;  /* 0=>preemptible, <0=>BUG */

	mm_segment_t		addr_limit;

	/*

	 * These stack pointers are overwritten on every system call or

	 * exception.  SP is also saved to the stack it can be recovered when

{						\

	.flags		= 0,			\

	.preempt_count	= INIT_PREEMPT_COUNT,	\

	.addr_limit	= KERNEL_DS,		\

}

#endif /* !__ASSEMBLY__ */

#define __disable_user_access()							\

	__asm__ __volatile__ ("csrc sstatus, %0" : : "r" (SR_SUM) : "memory")

/*

 * The fs value determines whether argument validity checking should be

 * performed or not.  If get_fs() == USER_DS, checking is performed, with

 * get_fs() == KERNEL_DS, checking is bypassed.

 *

 * For historical reasons, these macros are grossly misnamed.

 */

#define MAKE_MM_SEG(s)	((mm_segment_t) { (s) })

#define KERNEL_DS	MAKE_MM_SEG(~0UL)

#define USER_DS		MAKE_MM_SEG(TASK_SIZE)

#define get_fs()	(current_thread_info()->addr_limit)

static inline void set_fs(mm_segment_t fs)

{

	current_thread_info()->addr_limit = fs;

}

#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg)

#define user_addr_max()	(get_fs().seg)

/**

 * access_ok: - Checks if a user space pointer is valid

 * @addr: User space pointer to start of block to check

 */

static inline int __access_ok(unsigned long addr, unsigned long size)

{

	const mm_segment_t fs = get_fs();

	return size <= fs.seg && addr <= fs.seg - size;

	return size <= TASK_SIZE && addr <= TASK_SIZE - size;

}

/*

	}

	regs->epc = pc;

	regs->sp = sp;

	set_fs(USER_DS);

}

void flush_thread(void)