/* SPDX-License-Identifier: GPL-2.0 */
#include <asm/ptrace.h>

#include "bpf_jit_32.h"

#define SAVE_SZ         96
#define SCRATCH_OFF     72
#define BE_PTR(label)   be label
#define SIGN_EXTEND(reg)

#define SKF_MAX_NEG_OFF (-0x200000) /* SKF_LL_OFF from filter.h */

        .text
        .globl  bpf_jit_load_word
bpf_jit_load_word:
        cmp     r_OFF, 0
        bl      bpf_slow_path_word_neg
         nop
        .globl  bpf_jit_load_word_positive_offset
bpf_jit_load_word_positive_offset:
        sub     r_HEADLEN, r_OFF, r_TMP
        cmp     r_TMP, 3
        ble     bpf_slow_path_word
         add    r_SKB_DATA, r_OFF, r_TMP
        andcc   r_TMP, 3, %g0
        bne     load_word_unaligned
         nop
        retl
         ld     [r_TMP], r_A
load_word_unaligned:
        ldub    [r_TMP + 0x0], r_OFF
        ldub    [r_TMP + 0x1], r_TMP2
        sll     r_OFF, 8, r_OFF
        or      r_OFF, r_TMP2, r_OFF
        ldub    [r_TMP + 0x2], r_TMP2
        sll     r_OFF, 8, r_OFF
        or      r_OFF, r_TMP2, r_OFF
        ldub    [r_TMP + 0x3], r_TMP2
        sll     r_OFF, 8, r_OFF
        retl
         or     r_OFF, r_TMP2, r_A

        .globl  bpf_jit_load_half
bpf_jit_load_half:
        cmp     r_OFF, 0
        bl      bpf_slow_path_half_neg
         nop
        .globl  bpf_jit_load_half_positive_offset
bpf_jit_load_half_positive_offset:
        sub     r_HEADLEN, r_OFF, r_TMP
        cmp     r_TMP, 1
        ble     bpf_slow_path_half
         add    r_SKB_DATA, r_OFF, r_TMP
        andcc   r_TMP, 1, %g0
        bne     load_half_unaligned
         nop
        retl
         lduh   [r_TMP], r_A
load_half_unaligned:
        ldub    [r_TMP + 0x0], r_OFF
        ldub    [r_TMP + 0x1], r_TMP2
        sll     r_OFF, 8, r_OFF
        retl
         or     r_OFF, r_TMP2, r_A

        .globl  bpf_jit_load_byte
bpf_jit_load_byte:
        cmp     r_OFF, 0
        bl      bpf_slow_path_byte_neg
         nop
        .globl  bpf_jit_load_byte_positive_offset
bpf_jit_load_byte_positive_offset:
        cmp     r_OFF, r_HEADLEN
        bge     bpf_slow_path_byte
         nop
        retl
         ldub   [r_SKB_DATA + r_OFF], r_A

        .globl  bpf_jit_load_byte_msh
bpf_jit_load_byte_msh:
        cmp     r_OFF, 0
        bl      bpf_slow_path_byte_msh_neg
         nop
        .globl  bpf_jit_load_byte_msh_positive_offset
bpf_jit_load_byte_msh_positive_offset:
        cmp     r_OFF, r_HEADLEN
        bge     bpf_slow_path_byte_msh
         nop
        ldub    [r_SKB_DATA + r_OFF], r_OFF
        and     r_OFF, 0xf, r_OFF
        retl
         sll    r_OFF, 2, r_X

#define bpf_slow_path_common(LEN)       \
        save    %sp, -SAVE_SZ, %sp;     \
        mov     %i0, %o0;               \
        mov     r_OFF, %o1;             \
        add     %fp, SCRATCH_OFF, %o2;  \
        call    skb_copy_bits;          \
         mov    (LEN), %o3;             \
        cmp     %o0, 0;                 \
        restore;

bpf_slow_path_word:
        bpf_slow_path_common(4)
        bl      bpf_error
         ld     [%sp + SCRATCH_OFF], r_A
        retl
         nop
bpf_slow_path_half:
        bpf_slow_path_common(2)
        bl      bpf_error
         lduh   [%sp + SCRATCH_OFF], r_A
        retl
         nop
bpf_slow_path_byte:
        bpf_slow_path_common(1)
        bl      bpf_error
         ldub   [%sp + SCRATCH_OFF], r_A
        retl
         nop
bpf_slow_path_byte_msh:
        bpf_slow_path_common(1)
        bl      bpf_error
         ldub   [%sp + SCRATCH_OFF], r_A
        and     r_OFF, 0xf, r_OFF
        retl
         sll    r_OFF, 2, r_X

#define bpf_negative_common(LEN)                        \
        save    %sp, -SAVE_SZ, %sp;                     \
        mov     %i0, %o0;                               \
        mov     r_OFF, %o1;                             \
        SIGN_EXTEND(%o1);                               \
        call    bpf_internal_load_pointer_neg_helper;   \
         mov    (LEN), %o2;                             \
        mov     %o0, r_TMP;                             \
        cmp     %o0, 0;                                 \
        BE_PTR(bpf_error);                              \
         restore;

bpf_slow_path_word_neg:
        sethi   %hi(SKF_MAX_NEG_OFF), r_TMP
        cmp     r_OFF, r_TMP
        bl      bpf_error
         nop
        .globl  bpf_jit_load_word_negative_offset
bpf_jit_load_word_negative_offset:
        bpf_negative_common(4)
        andcc   r_TMP, 3, %g0
        bne     load_word_unaligned
         nop
        retl
         ld     [r_TMP], r_A

bpf_slow_path_half_neg:
        sethi   %hi(SKF_MAX_NEG_OFF), r_TMP
        cmp     r_OFF, r_TMP
        bl      bpf_error
         nop
        .globl  bpf_jit_load_half_negative_offset
bpf_jit_load_half_negative_offset:
        bpf_negative_common(2)
        andcc   r_TMP, 1, %g0
        bne     load_half_unaligned
         nop
        retl
         lduh   [r_TMP], r_A

bpf_slow_path_byte_neg:
        sethi   %hi(SKF_MAX_NEG_OFF), r_TMP
        cmp     r_OFF, r_TMP
        bl      bpf_error
         nop
        .globl  bpf_jit_load_byte_negative_offset
bpf_jit_load_byte_negative_offset:
        bpf_negative_common(1)
        retl
         ldub   [r_TMP], r_A

bpf_slow_path_byte_msh_neg:
        sethi   %hi(SKF_MAX_NEG_OFF), r_TMP
        cmp     r_OFF, r_TMP
        bl      bpf_error
         nop
        .globl  bpf_jit_load_byte_msh_negative_offset
bpf_jit_load_byte_msh_negative_offset:
        bpf_negative_common(1)
        ldub    [r_TMP], r_OFF
        and     r_OFF, 0xf, r_OFF
        retl
         sll    r_OFF, 2, r_X

bpf_error:
        /* Make the JIT program return zero.  The JIT epilogue
         * stores away the original %o7 into r_saved_O7.  The
         * normal leaf function return is to use "retl" which
         * would evalute to "jmpl %o7 + 8, %g0" but we want to
         * use the saved value thus the sequence you see here.
         */
        jmpl    r_saved_O7 + 8, %g0
         clr    %o0