Changeset 5203efb1 in mainline


Ignore:
Timestamp:
2010-09-12T07:56:18Z (14 years ago)
Author:
Jakub Jermar <jakub@…>
Branches:
lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export
Children:
553f430, dc94cb2
Parents:
2fa10f6 (diff), 76e1121f (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.
Message:

Merge from lp:~jakub/helenos/upa

Location:
kernel/arch/mips32
Files:
5 edited

Legend:

Unmodified
Added
Removed

  • kernel/arch/mips32/include/context_offset.h

    r2fa10f6 r5203efb1  
    6060# define OFFSET_F30     0x5c
    6161#endif /* KERNEL */
    62 
    63 /* istate_t */
    64 #define EOFFSET_AT     0x0
    65 #define EOFFSET_V0     0x4
    66 #define EOFFSET_V1     0x8
    67 #define EOFFSET_A0     0xc
    68 #define EOFFSET_A1     0x10
    69 #define EOFFSET_A2     0x14
    70 #define EOFFSET_A3     0x18
    71 #define EOFFSET_T0     0x1c
    72 #define EOFFSET_T1     0x20
    73 #define EOFFSET_T2     0x24
    74 #define EOFFSET_T3     0x28
    75 #define EOFFSET_T4     0x2c
    76 #define EOFFSET_T5     0x30
    77 #define EOFFSET_T6     0x34
    78 #define EOFFSET_T7     0x38
    79 #define EOFFSET_T8     0x3c
    80 #define EOFFSET_T9     0x40
    81 #define EOFFSET_GP     0x44
    82 #define EOFFSET_SP     0x48
    83 #define EOFFSET_RA     0x4c
    84 #define EOFFSET_LO     0x50
    85 #define EOFFSET_HI     0x54
    86 #define EOFFSET_STATUS 0x58
    87 #define EOFFSET_EPC    0x5c
    88 #define EOFFSET_K1     0x60
    89 #define REGISTER_SPACE 104      /* respect stack alignment */
    9062
    9163#ifdef __ASM__

  • kernel/arch/mips32/include/exception.h

    r2fa10f6 r5203efb1  
    6060
    6161typedef struct istate {
     62        /*
     63         * The first seven registers are arranged so that the istate structure
     64         * can be used both for exception handlers and for the syscall handler.
     65         */
     66        uint32_t a0;    /* arg1 */
     67        uint32_t a1;    /* arg2 */
     68        uint32_t a2;    /* arg3 */
     69        uint32_t a3;    /* arg4 */
     70        uint32_t t0;    /* arg5 */
     71        uint32_t t1;    /* arg6 */
     72        uint32_t v0;    /* arg7 */
     73        uint32_t v1;
    6274        uint32_t at;
    63         uint32_t v0;
    64         uint32_t v1;
    65         uint32_t a0;
    66         uint32_t a1;
    67         uint32_t a2;
    68         uint32_t a3;
    69         uint32_t t0;
    70         uint32_t t1;
    7175        uint32_t t2;
    7276        uint32_t t3;
    … …  
    7579        uint32_t t6;
    7680        uint32_t t7;
     81        uint32_t s0;
     82        uint32_t s1;
     83        uint32_t s2;
     84        uint32_t s3;
     85        uint32_t s4;
     86        uint32_t s5;
     87        uint32_t s6;
     88        uint32_t s7;
    7789        uint32_t t8;
    7890        uint32_t t9;
     91        uint32_t kt0;
     92        uint32_t kt1;   /* We use it as thread-local pointer */
    7993        uint32_t gp;
    8094        uint32_t sp;
     95        uint32_t s8;
    8196        uint32_t ra;
    8297       
    … …  
    8499        uint32_t hi;
    85100       
    86         uint32_t status;  /* cp0_status */
    87         uint32_t epc;     /* cp0_epc */
    88         uint32_t k1;      /* We use it as thread-local pointer */
     101        uint32_t status;        /* cp0_status */
     102        uint32_t epc;           /* cp0_epc */
     103
     104        uint32_t alignment;     /* to make sizeof(istate_t) a multiple of 8 */
    89105} istate_t;
    90106
    … …  
    108124NO_TRACE static inline unative_t istate_get_fp(istate_t *istate)
    109125{
    110         /* FIXME */
    111        
    112         return 0;
     126        return istate->sp;
    113127}
    114128

  • kernel/arch/mips32/src/debug/stacktrace.c

    r2fa10f6 r5203efb1  
    3131 */
    3232/** @file
     33 */
     34
     35/*
     36 * This stack tracing code is based on the suggested algorithm described on page
     37 * 3-27 and 3-28 of:
     38 *
     39 * SYSTEM V
     40 * APPLICATION BINARY INTERFACE
     41 *
     42 * MIPS RISC Processor
     43 * Supplement
     44 * 3rd Edition
     45 *
     46 * Unfortunately, GCC generates code which is not entirely compliant with this
     47 * method. For example, it places the "jr ra" instruction quite arbitrarily in
     48 * the middle of the function which makes the original algorithm unapplicable.
     49 *
     50 * We deal with this problem by simply not using those parts of the algorithm
     51 * that rely on the "jr ra" instruction occurring in the last basic block of a
     52 * function, which gives us still usable, but less reliable stack tracer. The
     53 * unreliability stems from the fact that under some circumstances it can become
     54 * confused and produce incorrect or incomplete stack trace. We apply extra
     55 * sanity checks so that the algorithm is still safe and should not crash the
     56 * system.
     57 *
     58 * Even though not perfect, our solution is pretty lightweight, especially when
     59 * compared with a prospective alternative solution based on additional
     60 * debugging information stored directly in the kernel image.
    3361 */
    3462
    … …  
    96124extern char ktext_end;
    97125
     126static bool bounds_check(uintptr_t pc)
     127{
     128        return (pc >= (uintptr_t) &ktext_start) &&
     129            (pc < (uintptr_t) &ktext_end);
     130}
     131
    98132static bool
    99133scan(stack_trace_context_t *ctx, uintptr_t *prev_fp, uintptr_t *prev_ra)
    … …  
    106140        do {
    107141                inst--;
     142                if (!bounds_check((uintptr_t) inst))
     143                        return false;
    108144#if 0
    109145                /*
    … …  
    180216                                        return false;
    181217                                /* too big offsets are suspicious */
    182                                 if (offset > 32 * 4)
     218                                if ((size_t) offset > sizeof(istate_t))
    183219                                        return false;
    184220
    … …  
    207243{
    208244        return !((ctx->fp == 0) || ((ctx->fp % 8) != 0) ||
    209             (ctx->pc % 4 != 0) || (ctx->pc < (uintptr_t) &ktext_start) ||
    210             (ctx->pc >= (uintptr_t) &ktext_end));
     245            (ctx->pc % 4 != 0) || !bounds_check(ctx->pc));
    211246}
    212247

  • kernel/arch/mips32/src/exception.c

    r2fa10f6 r5203efb1  
    7474void istate_decode(istate_t *istate)
    7575{
    76         printf("at=%p\tv0=%p\tv1=%p\n", istate->at, istate->v0, istate->v1);
    77         printf("a0=%p\ta1=%p\ta2=%p\n", istate->a0, istate->a1, istate->a2);
    78         printf("a3=%p\tt0=%p\tt1=%p\n", istate->a3, istate->t0, istate->t1);
    79         printf("t2=%p\tt3=%p\tt4=%p\n", istate->t2, istate->t3, istate->t4);
    80         printf("t5=%p\tt6=%p\tt7=%p\n", istate->t5, istate->t6, istate->t7);
    81         printf("t8=%p\tt9=%p\tgp=%p\n", istate->t8, istate->t9, istate->gp);
    82         printf("sp=%p\tra=%p\t\n", istate->sp, istate->ra);
    83         printf("lo=%p\thi=%p\t\n", istate->lo, istate->hi);
    84         printf("cp0_status=%p\tcp0_epc=%p\tk1=%p\n",
    85             istate->status, istate->epc, istate->k1);
     76        printf("epc=%p\tsta=%p\tlo =%p\thi =%p\n",
     77            istate->epc, istate->status, istate->lo, istate->hi);
     78        printf("a0 =%p\ta1 =%p\ta2 =%p\ta3 =%p\n",
     79            istate->a0, istate->a1, istate->a2, istate->a3);
     80        printf("t0 =%p\tt1 =%p\tt2 =%p\tt3 =%p\n",
     81            istate->t0, istate->t1, istate->t2, istate->t3);
     82        printf("t4 =%p\tt5 =%p\tt6 =%p\tt7 =%p\n",
     83            istate->t4, istate->t5, istate->t6, istate->t7);
     84        printf("t8 =%p\tt9 =%p\tv0 =%p\tv1 =%p\n",
     85            istate->t8, istate->t9, istate->v0, istate->v1);
     86        printf("s0 =%p\ts1 =%p\ts2 =%p\ts3 =%p\n",
     87            istate->s0, istate->s1, istate->s2, istate->s3);
     88        printf("s4 =%p\ts5 =%p\ts6 =%p\ts7 =%p\n",
     89            istate->s4, istate->s5, istate->s6, istate->s7);
     90        printf("s8 =%p\tat =%p\tkt0=%p\tkt1=%p\n",
     91            istate->s8, istate->at, istate->kt0, istate->kt1);
     92        printf("sp =%p\tra =%p\tgp =%p\n",
     93            istate->sp, istate->ra, istate->gp);
    8694}
    8795
    … …  
    97105                ASSERT(THREAD);
    98106                istate->epc += 4;
    99                 istate->v1 = istate->k1;
     107                istate->v1 = istate->kt1;
    100108        } else
    101109                unhandled_exception(n, istate);

  • kernel/arch/mips32/src/start.S

    r2fa10f6 r5203efb1  
    4646
    4747/*
    48  * Which status bits should are thread-local:
     48 * Which status bits are thread-local:
    4949 * KSU(UM), EXL, ERL, IE
    5050 */
    5151#define REG_SAVE_MASK 0x1f
     52
     53#define ISTATE_OFFSET_A0        0
     54#define ISTATE_OFFSET_A1        4
     55#define ISTATE_OFFSET_A2        8
     56#define ISTATE_OFFSET_A3        12
     57#define ISTATE_OFFSET_T0        16
     58#define ISTATE_OFFSET_T1        20
     59#define ISTATE_OFFSET_V0        24
     60#define ISTATE_OFFSET_V1        28
     61#define ISTATE_OFFSET_AT        32
     62#define ISTATE_OFFSET_T2        36
     63#define ISTATE_OFFSET_T3        40
     64#define ISTATE_OFFSET_T4        44
     65#define ISTATE_OFFSET_T5        48
     66#define ISTATE_OFFSET_T6        52
     67#define ISTATE_OFFSET_T7        56
     68#define ISTATE_OFFSET_S0        60
     69#define ISTATE_OFFSET_S1        64
     70#define ISTATE_OFFSET_S2        68
     71#define ISTATE_OFFSET_S3        72
     72#define ISTATE_OFFSET_S4        76
     73#define ISTATE_OFFSET_S5        80
     74#define ISTATE_OFFSET_S6        84
     75#define ISTATE_OFFSET_S7        88
     76#define ISTATE_OFFSET_T8        92
     77#define ISTATE_OFFSET_T9        96
     78#define ISTATE_OFFSET_KT0       100
     79#define ISTATE_OFFSET_KT1       104
     80#define ISTATE_OFFSET_GP        108
     81#define ISTATE_OFFSET_SP        112
     82#define ISTATE_OFFSET_S8        116
     83#define ISTATE_OFFSET_RA        120
     84#define ISTATE_OFFSET_LO        124
     85#define ISTATE_OFFSET_HI        128
     86#define ISTATE_OFFSET_STATUS    132
     87#define ISTATE_OFFSET_EPC       136
     88#define ISTATE_OFFSET_ALIGNMENT 140
     89
     90#define ISTATE_SOFT_SIZE        144
     91
     92/*
     93 * The fake ABI prologue is never executed and may not be part of the
     94 * procedure's body. Instead, it should be immediately preceding the procedure's
     95 * body. Its only purpose is to trick the stack trace walker into thinking that
     96 * the exception is more or less just a normal function call.
     97 */
     98.macro FAKE_ABI_PROLOGUE
     99        sub $sp, ISTATE_SOFT_SIZE
     100        sw $ra, ISTATE_OFFSET_EPC($sp)
     101.endm
    52102
    53103/*
    … …  
    58108 */
    59109.macro REGISTERS_STORE_AND_EXC_RESET r
    60         sw $at, EOFFSET_AT(\r)
    61         sw $v0, EOFFSET_V0(\r)
    62         sw $v1, EOFFSET_V1(\r)
    63         sw $a0, EOFFSET_A0(\r)
    64         sw $a1, EOFFSET_A1(\r)
    65         sw $a2, EOFFSET_A2(\r)
    66         sw $a3, EOFFSET_A3(\r)
    67         sw $t0, EOFFSET_T0(\r)
    68         sw $t1, EOFFSET_T1(\r)
    69         sw $t2, EOFFSET_T2(\r)
    70         sw $t3, EOFFSET_T3(\r)
    71         sw $t4, EOFFSET_T4(\r)
    72         sw $t5, EOFFSET_T5(\r)
    73         sw $t6, EOFFSET_T6(\r)
    74         sw $t7, EOFFSET_T7(\r)
    75         sw $t8, EOFFSET_T8(\r)
    76         sw $t9, EOFFSET_T9(\r)
     110        sw $at, ISTATE_OFFSET_AT(\r)
     111        sw $v0, ISTATE_OFFSET_V0(\r)
     112        sw $v1, ISTATE_OFFSET_V1(\r)
     113        sw $a0, ISTATE_OFFSET_A0(\r)
     114        sw $a1, ISTATE_OFFSET_A1(\r)
     115        sw $a2, ISTATE_OFFSET_A2(\r)
     116        sw $a3, ISTATE_OFFSET_A3(\r)
     117        sw $t0, ISTATE_OFFSET_T0(\r)
     118        sw $t1, ISTATE_OFFSET_T1(\r)
     119        sw $t2, ISTATE_OFFSET_T2(\r)
     120        sw $t3, ISTATE_OFFSET_T3(\r)
     121        sw $t4, ISTATE_OFFSET_T4(\r)
     122        sw $t5, ISTATE_OFFSET_T5(\r)
     123        sw $t6, ISTATE_OFFSET_T6(\r)
     124        sw $t7, ISTATE_OFFSET_T7(\r)
     125        sw $t8, ISTATE_OFFSET_T8(\r)
     126        sw $t9, ISTATE_OFFSET_T9(\r)
     127        sw $s0, ISTATE_OFFSET_S0(\r)
     128        sw $s1, ISTATE_OFFSET_S1(\r)
     129        sw $s2, ISTATE_OFFSET_S2(\r)
     130        sw $s3, ISTATE_OFFSET_S3(\r)
     131        sw $s4, ISTATE_OFFSET_S4(\r)
     132        sw $s5, ISTATE_OFFSET_S5(\r)
     133        sw $s6, ISTATE_OFFSET_S6(\r)
     134        sw $s7, ISTATE_OFFSET_S7(\r)
     135        sw $s8, ISTATE_OFFSET_S8(\r)
    77136       
    78137        mflo $at
    79         sw $at, EOFFSET_LO(\r)
     138        sw $at, ISTATE_OFFSET_LO(\r)
    80139        mfhi $at
    81         sw $at, EOFFSET_HI(\r)
    82        
    83         sw $gp, EOFFSET_GP(\r)
    84         sw $ra, EOFFSET_RA(\r)
    85         sw $k1, EOFFSET_K1(\r)
     140        sw $at, ISTATE_OFFSET_HI(\r)
     141       
     142        sw $gp, ISTATE_OFFSET_GP(\r)
     143        sw $ra, ISTATE_OFFSET_RA(\r)
     144        sw $k0, ISTATE_OFFSET_KT0(\r)
     145        sw $k1, ISTATE_OFFSET_KT1(\r)
    86146       
    87147        mfc0 $t0, $status
    … …  
    95155        and $t0, $t0, $t3
    96156       
    97         sw $t2, EOFFSET_STATUS(\r)
    98         sw $t1, EOFFSET_EPC(\r)
     157        sw $t2, ISTATE_OFFSET_STATUS(\r)
     158        sw $t1, ISTATE_OFFSET_EPC(\r)
    99159        mtc0 $t0, $status
    100160.endm
    … …  
    106166         */
    107167        mfc0 $t0, $status
    108         lw $t1,EOFFSET_STATUS(\r)
     168        lw $t1, ISTATE_OFFSET_STATUS(\r)
    109169       
    110170        /* mask UM, EXL, ERL, IE */
    … …  
    116176        mtc0 $t0, $status
    117177       
    118         lw $v0, EOFFSET_V0(\r)
    119         lw $v1, EOFFSET_V1(\r)
    120         lw $a0, EOFFSET_A0(\r)
    121         lw $a1, EOFFSET_A1(\r)
    122         lw $a2, EOFFSET_A2(\r)
    123         lw $a3, EOFFSET_A3(\r)
    124         lw $t0, EOFFSET_T0(\r)
    125         lw $t1, EOFFSET_T1(\r)
    126         lw $t2, EOFFSET_T2(\r)
    127         lw $t3, EOFFSET_T3(\r)
    128         lw $t4, EOFFSET_T4(\r)
    129         lw $t5, EOFFSET_T5(\r)
    130         lw $t6, EOFFSET_T6(\r)
    131         lw $t7, EOFFSET_T7(\r)
    132         lw $t8, EOFFSET_T8(\r)
    133         lw $t9, EOFFSET_T9(\r)
    134        
    135         lw $gp, EOFFSET_GP(\r)
    136         lw $ra, EOFFSET_RA(\r)
    137         lw $k1, EOFFSET_K1(\r)
    138        
    139         lw $at, EOFFSET_LO(\r)
     178        lw $v0, ISTATE_OFFSET_V0(\r)
     179        lw $v1, ISTATE_OFFSET_V1(\r)
     180        lw $a0, ISTATE_OFFSET_A0(\r)
     181        lw $a1, ISTATE_OFFSET_A1(\r)
     182        lw $a2, ISTATE_OFFSET_A2(\r)
     183        lw $a3, ISTATE_OFFSET_A3(\r)
     184        lw $t0, ISTATE_OFFSET_T0(\r)
     185        lw $t1, ISTATE_OFFSET_T1(\r)
     186        lw $t2, ISTATE_OFFSET_T2(\r)
     187        lw $t3, ISTATE_OFFSET_T3(\r)
     188        lw $t4, ISTATE_OFFSET_T4(\r)
     189        lw $t5, ISTATE_OFFSET_T5(\r)
     190        lw $t6, ISTATE_OFFSET_T6(\r)
     191        lw $t7, ISTATE_OFFSET_T7(\r)
     192        lw $t8, ISTATE_OFFSET_T8(\r)
     193        lw $t9, ISTATE_OFFSET_T9(\r)
     194       
     195        lw $gp, ISTATE_OFFSET_GP(\r)
     196        lw $ra, ISTATE_OFFSET_RA(\r)
     197        lw $k1, ISTATE_OFFSET_KT1(\r)
     198       
     199        lw $at, ISTATE_OFFSET_LO(\r)
    140200        mtlo $at
    141         lw $at, EOFFSET_HI(\r)
     201        lw $at, ISTATE_OFFSET_HI(\r)
    142202        mthi $at
    143203       
    144         lw $at, EOFFSET_EPC(\r)
     204        lw $at, ISTATE_OFFSET_EPC(\r)
    145205        mtc0 $at, $epc
    146206       
    147         lw $at, EOFFSET_AT(\r)
    148         lw $sp, EOFFSET_SP(\r)
     207        lw $at, ISTATE_OFFSET_AT(\r)
     208        lw $sp, ISTATE_OFFSET_SP(\r)
    149209.endm
    150210
    … …  
    159219       
    160220        beq $k0, $0, 1f
    161         add $k0, $sp, 0
     221        move $k0, $sp
    162222       
    163223        /* move $k0 pointer to kernel stack */
    … …  
    166226       
    167227        /* move $k0 (supervisor_sp) */
    168         lw $k0, 0($k0)
     228        lw $k0, ($k0)
    169229       
    170230        1:
    … …  
    202262        nop
    203263
     264        FAKE_ABI_PROLOGUE
    204265exception_handler:
    205266        KERNEL_STACK_TO_K0
    206267       
    207         sub $k0, REGISTER_SPACE
    208         sw $sp, EOFFSET_SP($k0)
     268        sub $k0, ISTATE_SOFT_SIZE
     269        sw $sp, ISTATE_OFFSET_SP($k0)
    209270        move $sp, $k0
    210271       
    … …  
    227288        /* the $sp is automatically restored to former value */
    228289        eret
    229 
    230 #define SS_SP      EOFFSET_SP
    231 #define SS_STATUS  EOFFSET_STATUS
    232 #define SS_EPC     EOFFSET_EPC
    233 #define SS_K1      EOFFSET_K1
    234290
    235291/** Syscall entry
    … …  
    249305 */
    250306syscall_shortcut:
    251         /* we have a lot of space on the stack, with free use */
    252307        mfc0 $t3, $epc
    253308        mfc0 $t2, $status
    254         sw $t3, SS_EPC($sp)  /* save EPC */
    255         sw $k1, SS_K1($sp)   /* save $k1 not saved on context switch */
     309        sw $t3, ISTATE_OFFSET_EPC($sp)  /* save EPC */
     310        sw $k1, ISTATE_OFFSET_KT1($sp)  /* save $k1 not saved on context switch */
    256311       
    257312        and $t4, $t2, REG_SAVE_MASK  /* save only KSU, EXL, ERL, IE */
    … …  
    260315        ori $t2, $t2, 0x1  /* set IE */
    261316       
    262         sw $t4, SS_STATUS($sp)
     317        sw $t4, ISTATE_OFFSET_STATUS($sp)
    263318        mtc0 $t2, $status
    264319       
    265320        /*
    266321         * Call the higher level system call handler.
    267          * We are going to reuse part of the unused exception stack frame.
    268322         *
    269323         */
    270         sw $t0, STACK_ARG4($sp)  /* save the 5th argument on the stack */
    271         sw $t1, STACK_ARG5($sp)  /* save the 6th argument on the stack */
     324        sw $t0, ISTATE_OFFSET_T0($sp)  /* save the 5th argument on the stack */
     325        sw $t1, ISTATE_OFFSET_T1($sp)  /* save the 6th argument on the stack */
    272326        jal syscall_handler
    273         sw $v0, STACK_ARG6($sp)  /* save the syscall number on the stack */
     327        sw $v0, ISTATE_OFFSET_V0($sp)  /* save the syscall number on the stack */
    274328       
    275329        /* restore status */
    276330        mfc0 $t2, $status
    277         lw $t3, SS_STATUS($sp)
     331        lw $t3, ISTATE_OFFSET_STATUS($sp)
    278332       
    279333        /*
    … …  
    288342       
    289343        /* restore epc + 4 */
    290         lw $t2, SS_EPC($sp)
    291         lw $k1, SS_K1($sp)
     344        lw $t2, ISTATE_OFFSET_EPC($sp)
     345        lw $k1, ISTATE_OFFSET_KT1($sp)
    292346        addi $t2, $t2, 4
    293347        mtc0 $t2, $epc
    294348       
    295         lw $sp, SS_SP($sp)  /* restore $sp */
    296         eret
    297 
     349        lw $sp, ISTATE_OFFSET_SP($sp)  /* restore $sp */
     350        eret
     351
     352        FAKE_ABI_PROLOGUE
    298353tlb_refill_handler:
    299354        KERNEL_STACK_TO_K0
    300         sub $k0, REGISTER_SPACE
     355        sub $k0, ISTATE_SOFT_SIZE
    301356        REGISTERS_STORE_AND_EXC_RESET $k0
    302         sw $sp,EOFFSET_SP($k0)
    303         add $sp, $k0, 0
     357        sw $sp, ISTATE_OFFSET_SP($k0)
     358        move $sp, $k0
    304359       
    305360        jal tlb_refill
    306         add $a0, $sp, 0
     361        move $a0, $sp
    307362       
    308363        REGISTERS_LOAD $sp
    309364        eret
    310365
     366        FAKE_ABI_PROLOGUE
    311367cache_error_handler:
    312368        KERNEL_STACK_TO_K0
    313         sub $k0, REGISTER_SPACE
     369        sub $k0, ISTATE_SOFT_SIZE
    314370        REGISTERS_STORE_AND_EXC_RESET $k0
    315         sw $sp,EOFFSET_SP($k0)
    316         add $sp, $k0, 0
     371        sw $sp, ISTATE_OFFSET_SP($k0)
     372        move $sp, $k0
    317373       
    318374        jal cache_error
    319         add $a0, $sp, 0
     375        move $a0, $sp
    320376       
    321377        REGISTERS_LOAD $sp
    … …  
    323379
    324380userspace_asm:
    325         add $sp, $a0, 0
    326         add $v0, $a1, 0
    327         add $t9, $a2, 0    /* set up correct entry into PIC code */
     381        move $sp, $a0
     382        move $v0, $a1
     383        move $t9, $a2      /* set up correct entry into PIC code */
    328384        xor $a0, $a0, $a0  /* $a0 is defined to hold pcb_ptr */
    329385                           /* set it to 0 */
Note: See TracChangeset for help on using the changeset viewer.