/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * Copyright (C) 2002 Paul Mackerras, IBM Corp.
 */
#include <linux/export.h>
#include <asm/processor.h>
#include <asm/ppc_asm.h>
#include <asm/asm-compat.h>
#include <asm/feature-fixups.h>

#ifndef SELFTEST_CASE
/* 0 == most CPUs, 1 == POWER6, 2 == Cell */
#define SELFTEST_CASE   0
#endif

#ifdef __BIG_ENDIAN__
#define sLd sld         /* Shift towards low-numbered address. */
#define sHd srd         /* Shift towards high-numbered address. */
#else
#define sLd srd         /* Shift towards low-numbered address. */
#define sHd sld         /* Shift towards high-numbered address. */
#endif

/*
 * These macros are used to generate exception table entries.
 * The exception handlers below use the original arguments
 * (stored on the stack) and the point where we're up to in
 * the destination buffer, i.e. the address of the first
 * unmodified byte.  Generally r3 points into the destination
 * buffer, but the first unmodified byte is at a variable
 * offset from r3.  In the code below, the symbol r3_offset
 * is set to indicate the current offset at each point in
 * the code.  This offset is then used as a negative offset
 * from the exception handler code, and those instructions
 * before the exception handlers are addi instructions that
 * adjust r3 to point to the correct place.
 */
        .macro  lex             /* exception handler for load */
100:    EX_TABLE(100b, .Lld_exc - r3_offset)
        .endm

        .macro  stex            /* exception handler for store */
100:    EX_TABLE(100b, .Lst_exc - r3_offset)
        .endm

        .align  7
_GLOBAL_TOC(__copy_tofrom_user)
#ifdef CONFIG_PPC_BOOK3S_64
BEGIN_FTR_SECTION
        nop
FTR_SECTION_ELSE
        b       __copy_tofrom_user_power7
ALT_FTR_SECTION_END_IFCLR(CPU_FTR_VMX_COPY)
#endif
_GLOBAL(__copy_tofrom_user_base)
        /* first check for a 4kB copy on a 4kB boundary */
        cmpldi  cr1,r5,16
        cmpdi   cr6,r5,4096
        or      r0,r3,r4
        neg     r6,r3           /* LS 3 bits = # bytes to 8-byte dest bdry */
        andi.   r0,r0,4095
        std     r3,-24(r1)
        crand   cr0*4+2,cr0*4+2,cr6*4+2
        std     r4,-16(r1)
        std     r5,-8(r1)
        dcbt    0,r4
        beq     .Lcopy_page_4K
        andi.   r6,r6,7
        PPC_MTOCRF(0x01,r5)
        blt     cr1,.Lshort_copy
/* Below we want to nop out the bne if we're on a CPU that has the
 * CPU_FTR_UNALIGNED_LD_STD bit set and the CPU_FTR_CP_USE_DCBTZ bit
 * cleared.
 * At the time of writing the only CPU that has this combination of bits
 * set is Power6.
 */
test_feature = (SELFTEST_CASE == 1)
BEGIN_FTR_SECTION
        nop
FTR_SECTION_ELSE
        bne     .Ldst_unaligned
ALT_FTR_SECTION_END(CPU_FTR_UNALIGNED_LD_STD | CPU_FTR_CP_USE_DCBTZ, \
                    CPU_FTR_UNALIGNED_LD_STD)
.Ldst_aligned:
        addi    r3,r3,-16
r3_offset = 16
test_feature = (SELFTEST_CASE == 0)
BEGIN_FTR_SECTION
        andi.   r0,r4,7
        bne     .Lsrc_unaligned
END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
        blt     cr1,.Ldo_tail           /* if < 16 bytes to copy */
        srdi    r0,r5,5
        cmpdi   cr1,r0,0
lex;    ld      r7,0(r4)
lex;    ld      r6,8(r4)
        addi    r4,r4,16
        mtctr   r0
        andi.   r0,r5,0x10
        beq     22f
        addi    r3,r3,16
r3_offset = 0
        addi    r4,r4,-16
        mr      r9,r7
        mr      r8,r6
        beq     cr1,72f
21:
lex;    ld      r7,16(r4)
lex;    ld      r6,24(r4)
        addi    r4,r4,32
stex;   std     r9,0(r3)
r3_offset = 8
stex;   std     r8,8(r3)
r3_offset = 16
22:
lex;    ld      r9,0(r4)
lex;    ld      r8,8(r4)
stex;   std     r7,16(r3)
r3_offset = 24
stex;   std     r6,24(r3)
        addi    r3,r3,32
r3_offset = 0
        bdnz    21b
72:
stex;   std     r9,0(r3)
r3_offset = 8
stex;   std     r8,8(r3)
r3_offset = 16
        andi.   r5,r5,0xf
        beq+    3f
        addi    r4,r4,16
.Ldo_tail:
        addi    r3,r3,16
r3_offset = 0
        bf      cr7*4+0,246f
lex;    ld      r9,0(r4)
        addi    r4,r4,8
stex;   std     r9,0(r3)
        addi    r3,r3,8
246:    bf      cr7*4+1,1f
lex;    lwz     r9,0(r4)
        addi    r4,r4,4
stex;   stw     r9,0(r3)
        addi    r3,r3,4
1:      bf      cr7*4+2,2f
lex;    lhz     r9,0(r4)
        addi    r4,r4,2
stex;   sth     r9,0(r3)
        addi    r3,r3,2
2:      bf      cr7*4+3,3f
lex;    lbz     r9,0(r4)
stex;   stb     r9,0(r3)
3:      li      r3,0
        blr

.Lsrc_unaligned:
r3_offset = 16
        srdi    r6,r5,3
        addi    r5,r5,-16
        subf    r4,r0,r4
        srdi    r7,r5,4
        sldi    r10,r0,3
        cmpldi  cr6,r6,3
        andi.   r5,r5,7
        mtctr   r7
        subfic  r11,r10,64
        add     r5,r5,r0
        bt      cr7*4+0,28f

lex;    ld      r9,0(r4)        /* 3+2n loads, 2+2n stores */
lex;    ld      r0,8(r4)
        sLd     r6,r9,r10
lex;    ldu     r9,16(r4)
        sHd     r7,r0,r11
        sLd     r8,r0,r10
        or      r7,r7,r6
        blt     cr6,79f
lex;    ld      r0,8(r4)
        b       2f

28:
lex;    ld      r0,0(r4)        /* 4+2n loads, 3+2n stores */
lex;    ldu     r9,8(r4)
        sLd     r8,r0,r10
        addi    r3,r3,-8
r3_offset = 24
        blt     cr6,5f
lex;    ld      r0,8(r4)
        sHd     r12,r9,r11
        sLd     r6,r9,r10
lex;    ldu     r9,16(r4)
        or      r12,r8,r12
        sHd     r7,r0,r11
        sLd     r8,r0,r10
        addi    r3,r3,16
r3_offset = 8
        beq     cr6,78f

1:      or      r7,r7,r6
lex;    ld      r0,8(r4)
stex;   std     r12,8(r3)
r3_offset = 16
2:      sHd     r12,r9,r11
        sLd     r6,r9,r10
lex;    ldu     r9,16(r4)
        or      r12,r8,r12
stex;   stdu    r7,16(r3)
r3_offset = 8
        sHd     r7,r0,r11
        sLd     r8,r0,r10
        bdnz    1b

78:
stex;   std     r12,8(r3)
r3_offset = 16
        or      r7,r7,r6
79:
stex;   std     r7,16(r3)
r3_offset = 24
5:      sHd     r12,r9,r11
        or      r12,r8,r12
stex;   std     r12,24(r3)
r3_offset = 32
        bne     6f
        li      r3,0
        blr
6:      cmpwi   cr1,r5,8
        addi    r3,r3,32
r3_offset = 0
        sLd     r9,r9,r10
        ble     cr1,7f
lex;    ld      r0,8(r4)
        sHd     r7,r0,r11
        or      r9,r7,r9
7:
        bf      cr7*4+1,1f
#ifdef __BIG_ENDIAN__
        rotldi  r9,r9,32
#endif
stex;   stw     r9,0(r3)
#ifdef __LITTLE_ENDIAN__
        rotrdi  r9,r9,32
#endif
        addi    r3,r3,4
1:      bf      cr7*4+2,2f
#ifdef __BIG_ENDIAN__
        rotldi  r9,r9,16
#endif
stex;   sth     r9,0(r3)
#ifdef __LITTLE_ENDIAN__
        rotrdi  r9,r9,16
#endif
        addi    r3,r3,2
2:      bf      cr7*4+3,3f
#ifdef __BIG_ENDIAN__
        rotldi  r9,r9,8
#endif
stex;   stb     r9,0(r3)
#ifdef __LITTLE_ENDIAN__
        rotrdi  r9,r9,8
#endif
3:      li      r3,0
        blr

.Ldst_unaligned:
r3_offset = 0
        PPC_MTOCRF(0x01,r6)             /* put #bytes to 8B bdry into cr7 */
        subf    r5,r6,r5
        li      r7,0
        cmpldi  cr1,r5,16
        bf      cr7*4+3,1f
100:    EX_TABLE(100b, .Lld_exc_r7)
        lbz     r0,0(r4)
100:    EX_TABLE(100b, .Lst_exc_r7)
        stb     r0,0(r3)
        addi    r7,r7,1
1:      bf      cr7*4+2,2f
100:    EX_TABLE(100b, .Lld_exc_r7)
        lhzx    r0,r7,r4
100:    EX_TABLE(100b, .Lst_exc_r7)
        sthx    r0,r7,r3
        addi    r7,r7,2
2:      bf      cr7*4+1,3f
100:    EX_TABLE(100b, .Lld_exc_r7)
        lwzx    r0,r7,r4
100:    EX_TABLE(100b, .Lst_exc_r7)
        stwx    r0,r7,r3
3:      PPC_MTOCRF(0x01,r5)
        add     r4,r6,r4
        add     r3,r6,r3
        b       .Ldst_aligned

.Lshort_copy:
r3_offset = 0
        bf      cr7*4+0,1f
lex;    lwz     r0,0(r4)
lex;    lwz     r9,4(r4)
        addi    r4,r4,8
stex;   stw     r0,0(r3)
stex;   stw     r9,4(r3)
        addi    r3,r3,8
1:      bf      cr7*4+1,2f
lex;    lwz     r0,0(r4)
        addi    r4,r4,4
stex;   stw     r0,0(r3)
        addi    r3,r3,4
2:      bf      cr7*4+2,3f
lex;    lhz     r0,0(r4)
        addi    r4,r4,2
stex;   sth     r0,0(r3)
        addi    r3,r3,2
3:      bf      cr7*4+3,4f
lex;    lbz     r0,0(r4)
stex;   stb     r0,0(r3)
4:      li      r3,0
        blr

/*
 * exception handlers follow
 * we have to return the number of bytes not copied
 * for an exception on a load, we set the rest of the destination to 0
 * Note that the number of bytes of instructions for adjusting r3 needs
 * to equal the amount of the adjustment, due to the trick of using
 * .Lld_exc - r3_offset as the handler address.
 */

.Lld_exc_r7:
        add     r3,r3,r7
        b       .Lld_exc

        /* adjust by 24 */
        addi    r3,r3,8
        nop
        /* adjust by 16 */
        addi    r3,r3,8
        nop
        /* adjust by 8 */
        addi    r3,r3,8
        nop

/*
 * Here we have had a fault on a load and r3 points to the first
 * unmodified byte of the destination.  We use the original arguments
 * and r3 to work out how much wasn't copied.  Since we load some
 * distance ahead of the stores, we continue copying byte-by-byte until
 * we hit the load fault again in order to copy as much as possible.
 */
.Lld_exc:
        ld      r6,-24(r1)
        ld      r4,-16(r1)
        ld      r5,-8(r1)
        subf    r6,r6,r3
        add     r4,r4,r6
        subf    r5,r6,r5        /* #bytes left to go */

/*
 * first see if we can copy any more bytes before hitting another exception
 */
        mtctr   r5
r3_offset = 0
100:    EX_TABLE(100b, .Ldone)
43:     lbz     r0,0(r4)
        addi    r4,r4,1
stex;   stb     r0,0(r3)
        addi    r3,r3,1
        bdnz    43b
        li      r3,0            /* huh? all copied successfully this time? */
        blr

/*
 * here we have trapped again, amount remaining is in ctr.
 */
.Ldone:
        mfctr   r3
        blr

/*
 * exception handlers for stores: we need to work out how many bytes
 * weren't copied, and we may need to copy some more.
 * Note that the number of bytes of instructions for adjusting r3 needs
 * to equal the amount of the adjustment, due to the trick of using
 * .Lst_exc - r3_offset as the handler address.
 */
.Lst_exc_r7:
        add     r3,r3,r7
        b       .Lst_exc

        /* adjust by 24 */
        addi    r3,r3,8
        nop
        /* adjust by 16 */
        addi    r3,r3,8
        nop
        /* adjust by 8 */
        addi    r3,r3,4
        /* adjust by 4 */
        addi    r3,r3,4
.Lst_exc:
        ld      r6,-24(r1)      /* original destination pointer */
        ld      r4,-16(r1)      /* original source pointer */
        ld      r5,-8(r1)       /* original number of bytes */
        add     r7,r6,r5
        /*
         * If the destination pointer isn't 8-byte aligned,
         * we may have got the exception as a result of a
         * store that overlapped a page boundary, so we may be
         * able to copy a few more bytes.
         */
17:     andi.   r0,r3,7
        beq     19f
        subf    r8,r6,r3        /* #bytes copied */
100:    EX_TABLE(100b,19f)
        lbzx    r0,r8,r4
100:    EX_TABLE(100b,19f)
        stb     r0,0(r3)
        addi    r3,r3,1
        cmpld   r3,r7
        blt     17b
19:     subf    r3,r3,r7        /* #bytes not copied in r3 */
        blr

/*
 * Routine to copy a whole page of data, optimized for POWER4.
 * On POWER4 it is more than 50% faster than the simple loop
 * above (following the .Ldst_aligned label).
 */
        .macro  exc
100:    EX_TABLE(100b, .Labort)
        .endm
.Lcopy_page_4K:
        std     r31,-32(1)
        std     r30,-40(1)
        std     r29,-48(1)
        std     r28,-56(1)
        std     r27,-64(1)
        std     r26,-72(1)
        std     r25,-80(1)
        std     r24,-88(1)
        std     r23,-96(1)
        std     r22,-104(1)
        std     r21,-112(1)
        std     r20,-120(1)
        li      r5,4096/32 - 1
        addi    r3,r3,-8
        li      r0,5
0:      addi    r5,r5,-24
        mtctr   r0
exc;    ld      r22,640(4)
exc;    ld      r21,512(4)
exc;    ld      r20,384(4)
exc;    ld      r11,256(4)
exc;    ld      r9,128(4)
exc;    ld      r7,0(4)
exc;    ld      r25,648(4)
exc;    ld      r24,520(4)
exc;    ld      r23,392(4)
exc;    ld      r10,264(4)
exc;    ld      r8,136(4)
exc;    ldu     r6,8(4)
        cmpwi   r5,24
1:
exc;    std     r22,648(3)
exc;    std     r21,520(3)
exc;    std     r20,392(3)
exc;    std     r11,264(3)
exc;    std     r9,136(3)
exc;    std     r7,8(3)
exc;    ld      r28,648(4)
exc;    ld      r27,520(4)
exc;    ld      r26,392(4)
exc;    ld      r31,264(4)
exc;    ld      r30,136(4)
exc;    ld      r29,8(4)
exc;    std     r25,656(3)
exc;    std     r24,528(3)
exc;    std     r23,400(3)
exc;    std     r10,272(3)
exc;    std     r8,144(3)
exc;    std     r6,16(3)
exc;    ld      r22,656(4)
exc;    ld      r21,528(4)
exc;    ld      r20,400(4)
exc;    ld      r11,272(4)
exc;    ld      r9,144(4)
exc;    ld      r7,16(4)
exc;    std     r28,664(3)
exc;    std     r27,536(3)
exc;    std     r26,408(3)
exc;    std     r31,280(3)
exc;    std     r30,152(3)
exc;    stdu    r29,24(3)
exc;    ld      r25,664(4)
exc;    ld      r24,536(4)
exc;    ld      r23,408(4)
exc;    ld      r10,280(4)
exc;    ld      r8,152(4)
exc;    ldu     r6,24(4)
        bdnz    1b
exc;    std     r22,648(3)
exc;    std     r21,520(3)
exc;    std     r20,392(3)
exc;    std     r11,264(3)
exc;    std     r9,136(3)
exc;    std     r7,8(3)
        addi    r4,r4,640
        addi    r3,r3,648
        bge     0b
        mtctr   r5
exc;    ld      r7,0(4)
exc;    ld      r8,8(4)
exc;    ldu     r9,16(4)
3:
exc;    ld      r10,8(4)
exc;    std     r7,8(3)
exc;    ld      r7,16(4)
exc;    std     r8,16(3)
exc;    ld      r8,24(4)
exc;    std     r9,24(3)
exc;    ldu     r9,32(4)
exc;    stdu    r10,32(3)
        bdnz    3b
4:
exc;    ld      r10,8(4)
exc;    std     r7,8(3)
exc;    std     r8,16(3)
exc;    std     r9,24(3)
exc;    std     r10,32(3)
9:      ld      r20,-120(1)
        ld      r21,-112(1)
        ld      r22,-104(1)
        ld      r23,-96(1)
        ld      r24,-88(1)
        ld      r25,-80(1)
        ld      r26,-72(1)
        ld      r27,-64(1)
        ld      r28,-56(1)
        ld      r29,-48(1)
        ld      r30,-40(1)
        ld      r31,-32(1)
        li      r3,0
        blr

/*
 * on an exception, reset to the beginning and jump back into the
 * standard __copy_tofrom_user
 */
.Labort:
        ld      r20,-120(1)
        ld      r21,-112(1)
        ld      r22,-104(1)
        ld      r23,-96(1)
        ld      r24,-88(1)
        ld      r25,-80(1)
        ld      r26,-72(1)
        ld      r27,-64(1)
        ld      r28,-56(1)
        ld      r29,-48(1)
        ld      r30,-40(1)
        ld      r31,-32(1)
        ld      r3,-24(r1)
        ld      r4,-16(r1)
        li      r5,4096
        b       .Ldst_aligned
EXPORT_SYMBOL(__copy_tofrom_user)
EXPORT_SYMBOL(__copy_tofrom_user_base)