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[SIGNAL][RV64] Added special unaligned cases handling #2248

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Jan 10, 2025
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[SIGNAL][RV64] Added special unaligned cases handling #2248

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46 changes: 45 additions & 1 deletion src/libtools/signals.c
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Original file line number Diff line number Diff line change
Expand Up @@ -663,7 +663,7 @@ int sigbus_specialcases(siginfo_t* info, void * ucntx, void* pc, void* _fpsimd)
ucontext_t *p = (ucontext_t *)ucntx;
uint32_t opcode = *(uint32_t*)pc;
struct fpsimd_context *fpsimd = (struct fpsimd_context *)_fpsimd;
//printf_log(LOG_INFO, "Checking SIGBUS special casses with pc=%p, opcode=%x, fpsimd=%p\n", pc, opcode, fpsimd);
//printf_log(LOG_INFO, "Checking SIGBUS special cases with pc=%p, opcode=%x, fpsimd=%p\n", pc, opcode, fpsimd);
if((opcode&0b10111111110000000000000000000000)==0b10111001000000000000000000000000) {
// this is STR
int scale = (opcode>>30)&3;
Expand Down Expand Up @@ -949,6 +949,33 @@ int sigbus_specialcases(siginfo_t* info, void * ucntx, void* pc, void* _fpsimd)
p->uc_mcontext.pc+=4; // go to next opcode
return 1;
}
#elif RV64
#define GET_FIELD(v, high, low) (((v) >> low) & ((1ULL << (high - low + 1)) - 1))
#define SIGN_EXT(val, val_sz) (((int32_t)(val) << (32 - (val_sz))) >> (32 - (val_sz)))

ucontext_t *p = (ucontext_t *)ucntx;
uint32_t inst = *(uint32_t*)pc;

uint32_t funct3 = GET_FIELD(inst, 14, 12);
uint32_t opcode = GET_FIELD(inst, 6, 0);
if (opcode == 0b0100011 && (funct3 == 0b010 /* SW */ || funct3 == 0b011 /* SD */)) {
int val = (inst >> 20) & 0x1f;
int dest = (inst >> 15) & 0x1f;
int64_t imm = (GET_FIELD(inst, 31, 25) << 5) | (GET_FIELD(inst, 11, 7));
imm = SIGN_EXT(imm, 12);
volatile uint8_t *addr = (void *)(p->uc_mcontext.__gregs[dest] + imm);
uint64_t value = p->uc_mcontext.__gregs[val];
for(int i = 0; i < (funct3 == 0b010 ? 4 : 8); ++i) {
addr[i] = (value >> (i * 8)) & 0xff;
}
p->uc_mcontext.__gregs[0] += 4; // pc += 4
return 1;
} else {
printf_log(LOG_NONE, "Unsupported SIGBUS special cases with pc=%p, opcode=%x\n", pc, inst);
}

#undef GET_FIELD
#undef SIGN_EXT
#endif
return 0;
}
Expand Down Expand Up @@ -1479,6 +1506,23 @@ void my_box64signalhandler(int32_t sig, siginfo_t* info, void * ucntx)
info->si_code = 2;
}
#endif
#ifdef RV64
if((sig==SIGSEGV) && (addr==pc) && (info->si_code==2) && (prot==(PROT_READ|PROT_WRITE|PROT_EXEC)) && sigbus_specialcases(info, ucntx, pc, fpsimd)) {
// special case fixed, restore everything and just continues
if(box64_log >= LOG_DEBUG || box64_showsegv) {
static void* old_pc[2] = {0};
static int old_pc_i = 0;
if(old_pc[0]!=pc && old_pc[1]!=pc) {
old_pc[old_pc_i++] = pc;
if(old_pc_i==2)
old_pc_i = 0;
printf_log(LOG_NONE, "Special unalinged cased fixed @%p, opcode=%08x (addr=%p)\n", pc, *(uint32_t *)pc, addr);
}
}
relockMutex(Locks);
return;
}
#endif
#ifdef DYNAREC
if((Locks & is_dyndump_locked) && ((sig==SIGSEGV) || (sig==SIGBUS)) && current_helper) {
printf_log(LOG_INFO, "FillBlock triggered a %s at %p from %p\n", (sig==SIGSEGV)?"segfault":"bus error", addr, pc);
Expand Down
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