tlbsrc.c

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/*
# _____     ___ ____     ___ ____
#  ____|   |    ____|   |        | |____|
# |     ___|   |____ ___|    ____| |    \    PS2DEV Open Source Project.
#-----------------------------------------------------------------------
# Licenced under Academic Free License version 2.0
# Review ps2sdk README & LICENSE files for further details.
*/
 
#include <kernel.h>
#include <ee_cop0_defs.h>
 
/* Doesn't work, but here are the COP0 register definitions:
#define Index           $0
#define EntryLo0        $2
#define EntryLo1        $3
#define PageMask        $5
#define Wired           $6
#define EntryHi         $10 */
 
struct SyscallPatchData{
        unsigned int syscall;
        void *function;
};
 
char *_kExecArg[] __attribute__((section(".kExecArg")));
char *_kExecArg[] = {NULL};                                     /* 0x80075330 */
 
//Function prototypes:
int PutTLBEntry(unsigned int PageMask, unsigned int EntryHi, unsigned int EntryLo0, unsigned int EntryLo1);
int SetTLBEntry(unsigned int index, unsigned int PageMask, unsigned int EntryHi, unsigned int EntryLo0, unsigned int EntryLo1);
int GetTLBEntry(unsigned int index, unsigned int *PageMask, unsigned int *EntryHi, unsigned int *EntryLo0, unsigned int *EntryLo1);
int ProbeTLBEntry(unsigned int EntryHi, unsigned int *PageMask, unsigned int *EntryLo0, unsigned int *EntryLo1);
int ExpandScratchPad(unsigned int page);
 
static const struct SyscallPatchData SyscallPatchData[]={
        { 0x55, &PutTLBEntry},
        { 0x56, &SetTLBEntry},
        { 0x57, &GetTLBEntry},
        { 0x58, &ProbeTLBEntry},
        { 0x59, &ExpandScratchPad},
        { 0x03, &_kExecArg},
};
 
int _start(int syscall) __attribute__((section(".start")));
 
/* 0x80075000 */
int _start(int syscall){
        unsigned int i;
 
        for(i=0; i<6; i++){
                if(SyscallPatchData[i].syscall==syscall){
                        return((unsigned int)SyscallPatchData[i].function);
                }
        }
 
        return 0;
}
 
/* 0x80075038 */
int PutTLBEntry(unsigned int PageMask, unsigned int EntryHi, unsigned int EntryLo0, unsigned int EntryLo1){
        int result;
 
        switch(EntryHi>>24){
                case 0x40:
                case 0x30:
                case 0x20:
                case 0x00:
                        __asm volatile( "mtc0 %1, $5\n"
                                        "mtc0 %2, $10\n"
                                        "mtc0 %3, $2\n"
                                        "mtc0 %4, $3\n"
                                        "sync.p\n"
                                        "tlbwr\n"
                                        "sync.p\n"
                                        "tlbp\n"
                                        "sync.p\n"
                                        "mfc0 %0, $0\n" :"=r"(result):"r"(PageMask),"r"(EntryHi),"r"(EntryLo0),"r"(EntryLo1));
                        break;
                case 0x50:
                case 0x10:
                default:        //SP193: I don't remember seeing a default case. Anyway... Keeping Compilers Happy (TM).
                        result=-1;
        }
 
        return result;
}
 
/* 0x800750c8 */
int SetTLBEntry(unsigned int index, unsigned int PageMask, unsigned int EntryHi, unsigned int EntryLo0, unsigned int EntryLo1){
        int result;
 
        if(index<0x30){
                __asm volatile( "mtc0 %0, $0\n"
                                "mtc0 %1, $5\n"
                                "mtc0 %2, $10\n"
                                "mtc0 %3, $2\n"
                                "mtc0 %4, $3\n"
                                "sync.p\n"
                                "tlbwi\n"
                                "sync.p\n" ::"r"(index),"r"(PageMask),"r"(EntryHi),"r"(EntryLo0),"r"(EntryLo1));
 
                result=index;
        }
        else result=-1;
 
        return result;
}
 
/* 0x80075108 */
int GetTLBEntry(unsigned int index, unsigned int *PageMask, unsigned int *EntryHi, unsigned int *EntryLo0, unsigned int *EntryLo1){
        int result;
 
        if(index<0x30){
                __asm volatile( "mtc0 %0, $0\n"
                                "sync.p\n"
                                "tlbr\n"
                                "sync.p\n"
                                "mfc0 $v0, $5\n"
                                "sw $v0, (%1)\n"
                                "mfc0 $v0, $10\n"
                                "sw $v0, (%2)\n"
                                "mfc0 $v0, $2\n"
                                "sw $v0, (%3)\n"
                                "mfc0 $v0, $3\n"
                                "sw $v0, (%4)\n" ::"r"(index),"r"(PageMask),"r"(EntryHi),"r"(EntryLo0),"r"(EntryLo1));
 
                result=index;
        }
        else result=-1;
 
        return result;
}
 
/* 0x80075158 */
int ProbeTLBEntry(unsigned int EntryHi, unsigned int *PageMask, unsigned int *EntryLo0, unsigned int *EntryLo1){
        int result, index;
 
        __asm volatile( "mtc0 %1, $10\n"
                        "sync.p\n"
                        "tlbp\n"
                        "sync.p\n"
                        "mfc0 %0, $0\n" :"=r"(index):"r"(EntryHi));
 
        if(index>=0){
                __asm volatile( "tlbr\n"
                                "sync.p\n"
                                "mfc0 $v0, $5\n"
                                "sw $v0, (%0)\n"
                                "mfc0 $v1, $2\n"
                                "sw $v1, (%1)\n"
                                "mfc0 $v0, $3\n"
                                "sw $v0, (%2)\n" ::"r"(PageMask),"r"(EntryLo0),"r"(EntryLo1));
 
                result=index;
        }
        else result=-1;
 
        return result;
}
 
/* 0x800751a8 */
int ExpandScratchPad(unsigned int page){
        int result, index;
        unsigned int PageMask, EntryHi, EntryLo0, EntryLo1;
 
        if(!(page&0xFFF)){
                if(0xFFFFE<page-1){
                        if((index=ProbeTLBEntry(0x70004000, &PageMask, &EntryLo0, &EntryLo1))>=0){
                                if(page==0){
                                        EntryHi=0xE0010000+((index-1)<<13);
 
                                        __asm volatile( "mfc0 $v0, $6\n"
                                                        "addiu $v0, $v0, 0xFFFF\n"
                                                        "mtc0 $v0, $6\n"
                                                        "mtc0 %0, $0\n"
                                                        "mtc0 $zero, $5\n"
                                                        "mtc0 %1, $10\n"
                                                        "mtc0 $zero, $2\n"
                                                        "mtc0 $zero, $3\n"
                                                        "sync.p\n"
                                                        "tlbwi\n"
                                                        "sync.p\n" ::"r"(index),"r"(EntryHi));
                                }
                                else{
                                        __asm volatile( "mfc0 %0, $6\n"
                                                        "addiu $v0, %0, 1\n"
                                                        "mtc0 $v0, $6\n" ::"r"(index));
                                }
                        }
 
                        if(page!=0){
                        /*      Not sure why this code saves the EntryLo0 and EntryLo1 values on the stack, and sets a word on the stack to zero, but does not use them:
 
                                0($sp)=0
                                4($sp)=$v0=(page+0x1000&0xFFFFF000)>>6|0x1F
                                8($sp)=$a0=(page&0xFFFFF000)>>6|0x1F */
 
                                EntryHi=0x70004000;
                                EntryLo0=((page+0x1000)&0xFFFFF000)>>6|0x1F;
                                EntryLo1=(page&0xFFFFF000)>>6|0x1F;
 
                                __asm volatile( "mtc0 %0, $0\n"
                                                "daddu $v1, $zero, $zero\n"
                                                "mtc0 $v1, $5\n"
                                                "mtc0 %1, $10\n"
                                                "mtc0 %2, $2\n"
                                                "mtc0 %3, $3\n"
                                                "sync.p\n"
                                                "tlbwi\n"
                                                "sync.p\n" ::"r"(index),"r"(EntryHi),"r"(EntryLo0),"r"(EntryLo1));
 
                                result=index;
                        }
                        else result=0;
                }
                else result=-1;
        }
        else result=-1;
 
        return result;
}