/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __PARISC_UACCESS_H
#define __PARISC_UACCESS_H

/*
 * User space memory access functions
 */
#include <asm/page.h>
#include <asm/cache.h>

#include <linux/bug.h>
#include <linux/string.h>

/*
 * Note that since kernel addresses are in a separate address space on
 * parisc, we don't need to do anything for access_ok().
 * We just let the page fault handler do the right thing. This also means
 * that put_user is the same as __put_user, etc.
 */

#define access_ok(uaddr, size)  \
        ( (uaddr) == (uaddr) )

#define put_user __put_user
#define get_user __get_user

#if !defined(CONFIG_64BIT)
#define LDD_USER(sr, val, ptr)  __get_user_asm64(sr, val, ptr)
#define STD_USER(sr, x, ptr)    __put_user_asm64(sr, x, ptr)
#else
#define LDD_USER(sr, val, ptr)  __get_user_asm(sr, val, "ldd", ptr)
#define STD_USER(sr, x, ptr)    __put_user_asm(sr, "std", x, ptr)
#endif

/*
 * The exception table contains two values: the first is the relative offset to
 * the address of the instruction that is allowed to fault, and the second is
 * the relative offset to the address of the fixup routine. Since relative
 * addresses are used, 32bit values are sufficient even on 64bit kernel.
 */

#define ARCH_HAS_RELATIVE_EXTABLE
struct exception_table_entry {
        int insn;       /* relative address of insn that is allowed to fault. */
        int fixup;      /* relative address of fixup routine */
};

#define ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr )\
        ".section __ex_table,\"aw\"\n"                     \
        ".word (" #fault_addr " - .), (" #except_addr " - .)\n\t" \
        ".previous\n"

/*
 * ASM_EXCEPTIONTABLE_ENTRY_EFAULT() creates a special exception table entry
 * (with lowest bit set) for which the fault handler in fixup_exception() will
 * load -EFAULT into %r8 for a read or write fault, and zeroes the target
 * register in case of a read fault in get_user().
 */
#define ASM_EXCEPTIONTABLE_ENTRY_EFAULT( fault_addr, except_addr )\
        ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr + 1)

#define __get_user_internal(sr, val, ptr)               \
({                                                      \
        register long __gu_err __asm__ ("r8") = 0;      \
                                                        \
        switch (sizeof(*(ptr))) {                       \
        case 1: __get_user_asm(sr, val, "ldb", ptr); break; \
        case 2: __get_user_asm(sr, val, "ldh", ptr); break; \
        case 4: __get_user_asm(sr, val, "ldw", ptr); break; \
        case 8: LDD_USER(sr, val, ptr); break;          \
        default: BUILD_BUG();                           \
        }                                               \
                                                        \
        __gu_err;                                       \
})

#define __get_user(val, ptr)                            \
({                                                      \
        __get_user_internal("%%sr3,", val, ptr);        \
})

#define __get_user_asm(sr, val, ldx, ptr)               \
{                                                       \
        register long __gu_val;                         \
                                                        \
        __asm__("1: " ldx " 0(" sr "%2),%0\n"           \
                "9:\n"                                  \
                ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \
                : "=r"(__gu_val), "=r"(__gu_err)        \
                : "r"(ptr), "1"(__gu_err));             \
                                                        \
        (val) = (__force __typeof__(*(ptr))) __gu_val;  \
}

#define HAVE_GET_KERNEL_NOFAULT
#define __get_kernel_nofault(dst, src, type, err_label) \
{                                                       \
        type __z;                                       \
        long __err;                                     \
        __err = __get_user_internal("%%sr0,", __z, (type *)(src)); \
        if (unlikely(__err))                            \
                goto err_label;                         \
        else                                            \
                *(type *)(dst) = __z;                   \
}


#if !defined(CONFIG_64BIT)

#define __get_user_asm64(sr, val, ptr)                  \
{                                                       \
        union {                                         \
                unsigned long long      l;              \
                __typeof__(*(ptr))      t;              \
        } __gu_tmp;                                     \
                                                        \
        __asm__("   copy %%r0,%R0\n"                    \
                "1: ldw 0(" sr "%2),%0\n"               \
                "2: ldw 4(" sr "%2),%R0\n"              \
                "9:\n"                                  \
                ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \
                ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, 9b) \
                : "=&r"(__gu_tmp.l), "=r"(__gu_err)     \
                : "r"(ptr), "1"(__gu_err));             \
                                                        \
        (val) = __gu_tmp.t;                             \
}

#endif /* !defined(CONFIG_64BIT) */


#define __put_user_internal(sr, x, ptr)                         \
({                                                              \
        register long __pu_err __asm__ ("r8") = 0;              \
        __typeof__(*(ptr)) __x = (__typeof__(*(ptr)))(x);       \
                                                                \
        switch (sizeof(*(ptr))) {                               \
        case 1: __put_user_asm(sr, "stb", __x, ptr); break;     \
        case 2: __put_user_asm(sr, "sth", __x, ptr); break;     \
        case 4: __put_user_asm(sr, "stw", __x, ptr); break;     \
        case 8: STD_USER(sr, __x, ptr); break;                  \
        default: BUILD_BUG();                                   \
        }                                                       \
                                                                \
        __pu_err;                                               \
})

#define __put_user(x, ptr)                                      \
({                                                              \
        __put_user_internal("%%sr3,", x, ptr);                  \
})

#define __put_kernel_nofault(dst, src, type, err_label)         \
{                                                               \
        type __z = *(type *)(src);                              \
        long __err;                                             \
        __err = __put_user_internal("%%sr0,", __z, (type *)(dst)); \
        if (unlikely(__err))                                    \
                goto err_label;                                 \
}




/*
 * The "__put_user/kernel_asm()" macros tell gcc they read from memory
 * instead of writing. This is because they do not write to any memory
 * gcc knows about, so there are no aliasing issues. These macros must
 * also be aware that fixups are executed in the context of the fault,
 * and any registers used there must be listed as clobbers.
 * r8 is already listed as err.
 */

#define __put_user_asm(sr, stx, x, ptr)                         \
        __asm__ __volatile__ (                                  \
                "1: " stx " %2,0(" sr "%1)\n"                   \
                "9:\n"                                          \
                ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b)         \
                : "=r"(__pu_err)                                \
                : "r"(ptr), "r"(x), "0"(__pu_err))


#if !defined(CONFIG_64BIT)

#define __put_user_asm64(sr, __val, ptr) do {                   \
        __asm__ __volatile__ (                                  \
                "1: stw %2,0(" sr "%1)\n"                       \
                "2: stw %R2,4(" sr "%1)\n"                      \
                "9:\n"                                          \
                ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b)         \
                ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, 9b)         \
                : "=r"(__pu_err)                                \
                : "r"(ptr), "r"(__val), "0"(__pu_err));         \
} while (0)

#endif /* !defined(CONFIG_64BIT) */


/*
 * Complex access routines -- external declarations
 */

extern long strncpy_from_user(char *, const char __user *, long);
extern __must_check unsigned lclear_user(void __user *, unsigned long);
extern __must_check long strnlen_user(const char __user *src, long n);
/*
 * Complex access routines -- macros
 */

#define clear_user lclear_user
#define __clear_user lclear_user

unsigned long __must_check raw_copy_to_user(void __user *dst, const void *src,
                                            unsigned long len);
unsigned long __must_check raw_copy_from_user(void *dst, const void __user *src,
                                            unsigned long len);
#define INLINE_COPY_TO_USER
#define INLINE_COPY_FROM_USER

struct pt_regs;
int fixup_exception(struct pt_regs *regs);

#endif /* __PARISC_UACCESS_H */