/* SPDX-License-Identifier: GPL-2.0 */
/* copy_user.S: Sparc optimized copy_from_user and copy_to_user code.
 *
 *  Copyright(C) 1995 Linus Torvalds
 *  Copyright(C) 1996 David S. Miller
 *  Copyright(C) 1996 Eddie C. Dost
 *  Copyright(C) 1996,1998 Jakub Jelinek
 *
 * derived from:
 *      e-mail between David and Eddie.
 *
 * Returns 0 if successful, otherwise count of bytes not copied yet
 */

#include <linux/export.h>
#include <asm/ptrace.h>
#include <asm/asmmacro.h>
#include <asm/page.h>
#include <asm/thread_info.h>

/* Work around cpp -rob */
#define ALLOC #alloc
#define EXECINSTR #execinstr

#define EX_ENTRY(l1, l2)                        \
        .section __ex_table,ALLOC;              \
        .align  4;                              \
        .word   l1, l2;                         \
        .text;

#define EX(x,y,a,b)                             \
98:     x,y;                                    \
        .section .fixup,ALLOC,EXECINSTR;        \
        .align  4;                              \
99:     retl;                                   \
         a, b, %o0;                             \
        EX_ENTRY(98b, 99b)

#define EX2(x,y,c,d,e,a,b)                      \
98:     x,y;                                    \
        .section .fixup,ALLOC,EXECINSTR;        \
        .align  4;                              \
99:     c, d, e;                                \
        retl;                                   \
         a, b, %o0;                             \
        EX_ENTRY(98b, 99b)

#define EXO2(x,y)                               \
98:     x, y;                                   \
        EX_ENTRY(98b, 97f)

#define LD(insn, src, offset, reg, label)       \
98:     insn [%src + (offset)], %reg;           \
        .section .fixup,ALLOC,EXECINSTR;        \
99:     ba      label;                          \
         mov    offset, %g5;                    \
        EX_ENTRY(98b, 99b)

#define ST(insn, dst, offset, reg, label)       \
98:     insn %reg, [%dst + (offset)];           \
        .section .fixup,ALLOC,EXECINSTR;        \
99:     ba      label;                          \
         mov    offset, %g5;                    \
        EX_ENTRY(98b, 99b)

/* Both these macros have to start with exactly the same insn */
/* left: g7 + (g1 % 128) - offset */
#define MOVE_BIGCHUNK(src, dst, offset, t0, t1, t2, t3, t4, t5, t6, t7) \
        LD(ldd, src, offset + 0x00, t0, bigchunk_fault) \
        LD(ldd, src, offset + 0x08, t2, bigchunk_fault) \
        LD(ldd, src, offset + 0x10, t4, bigchunk_fault) \
        LD(ldd, src, offset + 0x18, t6, bigchunk_fault) \
        ST(st, dst, offset + 0x00, t0, bigchunk_fault)  \
        ST(st, dst, offset + 0x04, t1, bigchunk_fault)  \
        ST(st, dst, offset + 0x08, t2, bigchunk_fault)  \
        ST(st, dst, offset + 0x0c, t3, bigchunk_fault)  \
        ST(st, dst, offset + 0x10, t4, bigchunk_fault)  \
        ST(st, dst, offset + 0x14, t5, bigchunk_fault)  \
        ST(st, dst, offset + 0x18, t6, bigchunk_fault)  \
        ST(st, dst, offset + 0x1c, t7, bigchunk_fault)

/* left: g7 + (g1 % 128) - offset */
#define MOVE_BIGALIGNCHUNK(src, dst, offset, t0, t1, t2, t3, t4, t5, t6, t7) \
        LD(ldd, src, offset + 0x00, t0, bigchunk_fault) \
        LD(ldd, src, offset + 0x08, t2, bigchunk_fault) \
        LD(ldd, src, offset + 0x10, t4, bigchunk_fault) \
        LD(ldd, src, offset + 0x18, t6, bigchunk_fault) \
        ST(std, dst, offset + 0x00, t0, bigchunk_fault) \
        ST(std, dst, offset + 0x08, t2, bigchunk_fault) \
        ST(std, dst, offset + 0x10, t4, bigchunk_fault) \
        ST(std, dst, offset + 0x18, t6, bigchunk_fault)

        .section .fixup,#alloc,#execinstr
bigchunk_fault:
        sub     %g7, %g5, %o0
        and     %g1, 127, %g1
        retl
         add    %o0, %g1, %o0

/* left: offset + 16 + (g1 % 16) */
#define MOVE_LASTCHUNK(src, dst, offset, t0, t1, t2, t3) \
        LD(ldd, src, -(offset + 0x10), t0, lastchunk_fault)     \
        LD(ldd, src, -(offset + 0x08), t2, lastchunk_fault)     \
        ST(st, dst, -(offset + 0x10), t0, lastchunk_fault)      \
        ST(st, dst, -(offset + 0x0c), t1, lastchunk_fault)      \
        ST(st, dst, -(offset + 0x08), t2, lastchunk_fault)      \
        ST(st, dst, -(offset + 0x04), t3, lastchunk_fault)

        .section .fixup,#alloc,#execinstr
lastchunk_fault:
        and     %g1, 15, %g1
        retl
         sub    %g1, %g5, %o0

/* left: o3 + (o2 % 16) - offset */
#define MOVE_HALFCHUNK(src, dst, offset, t0, t1, t2, t3) \
        LD(lduh, src, offset + 0x00, t0, halfchunk_fault)       \
        LD(lduh, src, offset + 0x02, t1, halfchunk_fault)       \
        LD(lduh, src, offset + 0x04, t2, halfchunk_fault)       \
        LD(lduh, src, offset + 0x06, t3, halfchunk_fault)       \
        ST(sth, dst, offset + 0x00, t0, halfchunk_fault)        \
        ST(sth, dst, offset + 0x02, t1, halfchunk_fault)        \
        ST(sth, dst, offset + 0x04, t2, halfchunk_fault)        \
        ST(sth, dst, offset + 0x06, t3, halfchunk_fault)

/* left: o3 + (o2 % 16) + offset + 2 */
#define MOVE_SHORTCHUNK(src, dst, offset, t0, t1) \
        LD(ldub, src, -(offset + 0x02), t0, halfchunk_fault)    \
        LD(ldub, src, -(offset + 0x01), t1, halfchunk_fault)    \
        ST(stb, dst, -(offset + 0x02), t0, halfchunk_fault)     \
        ST(stb, dst, -(offset + 0x01), t1, halfchunk_fault)

        .section .fixup,#alloc,#execinstr
halfchunk_fault:
        and     %o2, 15, %o2
        sub     %o3, %g5, %o3
        retl
         add    %o2, %o3, %o0

/* left: offset + 2 + (o2 % 2) */
#define MOVE_LAST_SHORTCHUNK(src, dst, offset, t0, t1) \
        LD(ldub, src, -(offset + 0x02), t0, last_shortchunk_fault)      \
        LD(ldub, src, -(offset + 0x01), t1, last_shortchunk_fault)      \
        ST(stb, dst, -(offset + 0x02), t0, last_shortchunk_fault)       \
        ST(stb, dst, -(offset + 0x01), t1, last_shortchunk_fault)

        .section .fixup,#alloc,#execinstr
last_shortchunk_fault:
        and     %o2, 1, %o2
        retl
         sub    %o2, %g5, %o0

        .text
        .align  4

        .globl  __copy_user_begin
__copy_user_begin:

        .globl  __copy_user
        EXPORT_SYMBOL(__copy_user)
dword_align:
        andcc   %o1, 1, %g0
        be      4f
         andcc  %o1, 2, %g0

        EXO2(ldub [%o1], %g2)
        add     %o1, 1, %o1
        EXO2(stb %g2, [%o0])
        sub     %o2, 1, %o2
        bne     3f
         add    %o0, 1, %o0

        EXO2(lduh [%o1], %g2)
        add     %o1, 2, %o1
        EXO2(sth %g2, [%o0])
        sub     %o2, 2, %o2
        b       3f
         add    %o0, 2, %o0
4:
        EXO2(lduh [%o1], %g2)
        add     %o1, 2, %o1
        EXO2(sth %g2, [%o0])
        sub     %o2, 2, %o2
        b       3f
         add    %o0, 2, %o0

__copy_user:    /* %o0=dst %o1=src %o2=len */
        xor     %o0, %o1, %o4
1:
        andcc   %o4, 3, %o5
2:
        bne     cannot_optimize
         cmp    %o2, 15

        bleu    short_aligned_end
         andcc  %o1, 3, %g0

        bne     dword_align
3:
         andcc  %o1, 4, %g0

        be      2f
         mov    %o2, %g1

        EXO2(ld [%o1], %o4)
        sub     %g1, 4, %g1
        EXO2(st %o4, [%o0])
        add     %o1, 4, %o1
        add     %o0, 4, %o0
2:
        andcc   %g1, 0xffffff80, %g7
        be      3f
         andcc  %o0, 4, %g0

        be      ldd_std + 4
5:
        MOVE_BIGCHUNK(o1, o0, 0x00, o2, o3, o4, o5, g2, g3, g4, g5)
        MOVE_BIGCHUNK(o1, o0, 0x20, o2, o3, o4, o5, g2, g3, g4, g5)
        MOVE_BIGCHUNK(o1, o0, 0x40, o2, o3, o4, o5, g2, g3, g4, g5)
        MOVE_BIGCHUNK(o1, o0, 0x60, o2, o3, o4, o5, g2, g3, g4, g5)
        subcc   %g7, 128, %g7
        add     %o1, 128, %o1
        bne     5b
         add    %o0, 128, %o0
3:
        andcc   %g1, 0x70, %g7
        be      copy_user_table_end
         andcc  %g1, 8, %g0

        sethi   %hi(copy_user_table_end), %o5
        srl     %g7, 1, %o4
        add     %g7, %o4, %o4
        add     %o1, %g7, %o1
        sub     %o5, %o4, %o5
        jmpl    %o5 + %lo(copy_user_table_end), %g0
         add    %o0, %g7, %o0

        MOVE_LASTCHUNK(o1, o0, 0x60, g2, g3, g4, g5)
        MOVE_LASTCHUNK(o1, o0, 0x50, g2, g3, g4, g5)
        MOVE_LASTCHUNK(o1, o0, 0x40, g2, g3, g4, g5)
        MOVE_LASTCHUNK(o1, o0, 0x30, g2, g3, g4, g5)
        MOVE_LASTCHUNK(o1, o0, 0x20, g2, g3, g4, g5)
        MOVE_LASTCHUNK(o1, o0, 0x10, g2, g3, g4, g5)
        MOVE_LASTCHUNK(o1, o0, 0x00, g2, g3, g4, g5)
copy_user_table_end:
        be      copy_user_last7
         andcc  %g1, 4, %g0

        EX(ldd  [%o1], %g2, and %g1, 0xf)
        add     %o0, 8, %o0
        add     %o1, 8, %o1
        EX(st   %g2, [%o0 - 0x08], and %g1, 0xf)
        EX2(st  %g3, [%o0 - 0x04], and %g1, 0xf, %g1, sub %g1, 4)
copy_user_last7:
        be      1f
         andcc  %g1, 2, %g0

        EX(ld   [%o1], %g2, and %g1, 7)
        add     %o1, 4, %o1
        EX(st   %g2, [%o0], and %g1, 7)
        add     %o0, 4, %o0
1:
        be      1f
         andcc  %g1, 1, %g0

        EX(lduh [%o1], %g2, and %g1, 3)
        add     %o1, 2, %o1
        EX(sth  %g2, [%o0], and %g1, 3)
        add     %o0, 2, %o0
1:
        be      1f
         nop

        EX(ldub [%o1], %g2, add %g0, 1)
        EX(stb  %g2, [%o0], add %g0, 1)
1:
        retl
         clr    %o0

ldd_std:
        MOVE_BIGALIGNCHUNK(o1, o0, 0x00, o2, o3, o4, o5, g2, g3, g4, g5)
        MOVE_BIGALIGNCHUNK(o1, o0, 0x20, o2, o3, o4, o5, g2, g3, g4, g5)
        MOVE_BIGALIGNCHUNK(o1, o0, 0x40, o2, o3, o4, o5, g2, g3, g4, g5)
        MOVE_BIGALIGNCHUNK(o1, o0, 0x60, o2, o3, o4, o5, g2, g3, g4, g5)
        subcc   %g7, 128, %g7
        add     %o1, 128, %o1
        bne     ldd_std
         add    %o0, 128, %o0

        andcc   %g1, 0x70, %g7
        be      copy_user_table_end
         andcc  %g1, 8, %g0

        sethi   %hi(copy_user_table_end), %o5
        srl     %g7, 1, %o4
        add     %g7, %o4, %o4
        add     %o1, %g7, %o1
        sub     %o5, %o4, %o5
        jmpl    %o5 + %lo(copy_user_table_end), %g0
         add    %o0, %g7, %o0

cannot_optimize:
        bleu    short_end
         cmp    %o5, 2

        bne     byte_chunk
         and    %o2, 0xfffffff0, %o3
         
        andcc   %o1, 1, %g0
        be      10f
         nop

        EXO2(ldub [%o1], %g2)
        add     %o1, 1, %o1
        EXO2(stb %g2, [%o0])
        sub     %o2, 1, %o2
        andcc   %o2, 0xfffffff0, %o3
        be      short_end
         add    %o0, 1, %o0
10:
        MOVE_HALFCHUNK(o1, o0, 0x00, g2, g3, g4, g5)
        MOVE_HALFCHUNK(o1, o0, 0x08, g2, g3, g4, g5)
        subcc   %o3, 0x10, %o3
        add     %o1, 0x10, %o1
        bne     10b
         add    %o0, 0x10, %o0
        b       2f
         and    %o2, 0xe, %o3
        
byte_chunk:
        MOVE_SHORTCHUNK(o1, o0, -0x02, g2, g3)
        MOVE_SHORTCHUNK(o1, o0, -0x04, g2, g3)
        MOVE_SHORTCHUNK(o1, o0, -0x06, g2, g3)
        MOVE_SHORTCHUNK(o1, o0, -0x08, g2, g3)
        MOVE_SHORTCHUNK(o1, o0, -0x0a, g2, g3)
        MOVE_SHORTCHUNK(o1, o0, -0x0c, g2, g3)
        MOVE_SHORTCHUNK(o1, o0, -0x0e, g2, g3)
        MOVE_SHORTCHUNK(o1, o0, -0x10, g2, g3)
        subcc   %o3, 0x10, %o3
        add     %o1, 0x10, %o1
        bne     byte_chunk
         add    %o0, 0x10, %o0

short_end:
        and     %o2, 0xe, %o3
2:
        sethi   %hi(short_table_end), %o5
        sll     %o3, 3, %o4
        add     %o0, %o3, %o0
        sub     %o5, %o4, %o5
        add     %o1, %o3, %o1
        jmpl    %o5 + %lo(short_table_end), %g0
         andcc  %o2, 1, %g0
        MOVE_LAST_SHORTCHUNK(o1, o0, 0x0c, g2, g3)
        MOVE_LAST_SHORTCHUNK(o1, o0, 0x0a, g2, g3)
        MOVE_LAST_SHORTCHUNK(o1, o0, 0x08, g2, g3)
        MOVE_LAST_SHORTCHUNK(o1, o0, 0x06, g2, g3)
        MOVE_LAST_SHORTCHUNK(o1, o0, 0x04, g2, g3)
        MOVE_LAST_SHORTCHUNK(o1, o0, 0x02, g2, g3)
        MOVE_LAST_SHORTCHUNK(o1, o0, 0x00, g2, g3)
short_table_end:
        be      1f
         nop
        EX(ldub [%o1], %g2, add %g0, 1)
        EX(stb  %g2, [%o0], add %g0, 1)
1:
        retl
         clr    %o0

short_aligned_end:
        bne     short_end
         andcc  %o2, 8, %g0

        be      1f
         andcc  %o2, 4, %g0

        EXO2(ld [%o1 + 0x00], %g2)
        EXO2(ld [%o1 + 0x04], %g3)
        add     %o1, 8, %o1
        EXO2(st %g2, [%o0 + 0x00])
        EX(st   %g3, [%o0 + 0x04], sub %o2, 4)
        add     %o0, 8, %o0
1:
        b       copy_user_last7
         mov    %o2, %g1

        .section .fixup,#alloc,#execinstr
        .align  4
97:
        retl
         mov    %o2, %o0

        .globl  __copy_user_end
__copy_user_end: