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Remove stackoverflow error, have one CORE_INTERNAL error for catastrophic crash

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This commit is contained in:
Toby Jaffey 2025-12-10 18:42:34 +00:00
parent 59f5d6449b
commit 508d41c8c5
10 changed files with 163 additions and 57 deletions
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96
uvm32/uvm32.c
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@ -141,7 +141,7 @@ uint32_t uvm32_run(uvm32_state_t *vmst, uvm32_evt_t *evt, uint32_t instr_meter)
uint32_t num_instr = 0;
if (vmst->stack_canary != UVM32_NULL && *vmst->stack_canary != STACK_CANARY_VALUE) {
setStatusErr(vmst, UVM32_ERR_STACKOVERFLOW);
setStatusErr(vmst, UVM32_ERR_INTERNAL_CORE);
setup_err_evt(vmst, evt);
return num_instr;
}
@ -159,50 +159,58 @@ uint32_t uvm32_run(uvm32_state_t *vmst, uvm32_evt_t *evt, uint32_t instr_meter)
uint64_t elapsedUs = 1;
uint32_t ret;
ret = MiniRV32IMAStep(vmst, &vmst->core, vmst->memory, 0, elapsedUs, 1);
if (3 == ret) {
// Fetch registers used by syscall
const uint32_t syscall = vmst->core.regs[17]; // a7
// on exception we should jump to mtvec, but we handle directly
// and skip over the ecall instruction
vmst->core.pc += 4;
switch(syscall) {
// inbuilt syscalls
case UVM32_SYSCALL_HALT:
setStatus(vmst, UVM32_STATUS_ENDED);
break;
case UVM32_SYSCALL_STACKPROTECT: {
// don't allow errant code to change it once set
if (vmst->stack_canary == (uint8_t *)UVM32_NULL) {
uint32_t param0 = vmst->core.regs[10]; // a0
uint32_t mem_offset = param0 - MINIRV32_RAM_IMAGE_OFFSET;
switch(ret) {
case 0: // ok
break;
case 12: { // ecall
// Fetch registers used by syscall
const uint32_t syscall = vmst->core.regs[17]; // a7
// on exception we should jump to mtvec, but we handle directly
// and skip over the ecall instruction
vmst->core.pc += 4;
switch(syscall) {
// inbuilt syscalls
case UVM32_SYSCALL_HALT:
setStatus(vmst, UVM32_STATUS_ENDED);
break;
case UVM32_SYSCALL_STACKPROTECT: {
// don't allow errant code to change it once set
if (vmst->stack_canary == (uint8_t *)UVM32_NULL) {
uint32_t param0 = vmst->core.regs[10]; // a0
uint32_t mem_offset = param0 - MINIRV32_RAM_IMAGE_OFFSET;
mem_offset &= ~0xF; // round up by 16 bytes
mem_offset += 16*4;
// check data fits in ram
if (mem_offset > UVM32_MEMORY_SIZE) {
setStatusErr(vmst, UVM32_ERR_STACKOVERFLOW);
setup_err_evt(vmst, evt);
// check data fits in ram
if (mem_offset > UVM32_MEMORY_SIZE) {
setStatusErr(vmst, UVM32_ERR_INTERNAL_CORE);
setup_err_evt(vmst, evt);
}
// check canary is inside valid memory
if (mem_offset < UVM32_MEMORY_SIZE) {
// set canary
vmst->stack_canary = &vmst->memory[mem_offset];
*vmst->stack_canary = STACK_CANARY_VALUE;
}
}
// check canary is inside valid memory
if (mem_offset < UVM32_MEMORY_SIZE) {
// set canary
vmst->stack_canary = &vmst->memory[mem_offset];
*vmst->stack_canary = STACK_CANARY_VALUE;
}
}
} break;
default:
// user defined syscalls
vmst->ioevt.typ = UVM32_EVT_SYSCALL;
vmst->ioevt.data.syscall.code = syscall;
vmst->ioevt.data.syscall.ret = &vmst->core.regs[12]; // a2
vmst->ioevt.data.syscall.params[0] = &vmst->core.regs[10]; // a0
vmst->ioevt.data.syscall.params[1] = &vmst->core.regs[11]; // a1
setStatus(vmst, UVM32_STATUS_PAUSED);
break;
}
} else if (ret != 0) {
// unhandled exception
setStatusErr(vmst, UVM32_ERR_INTERNAL_CORE);
setup_err_evt(vmst, evt);
} break;
default:
// user defined syscalls
vmst->ioevt.typ = UVM32_EVT_SYSCALL;
vmst->ioevt.data.syscall.code = syscall;
vmst->ioevt.data.syscall.ret = &vmst->core.regs[12]; // a2
vmst->ioevt.data.syscall.params[0] = &vmst->core.regs[10]; // a0
vmst->ioevt.data.syscall.params[1] = &vmst->core.regs[11]; // a1
setStatus(vmst, UVM32_STATUS_PAUSED);
break;
} // end switch(syscall)
} break; // end ecall
default:
// unhandled exception
setStatusErr(vmst, UVM32_ERR_INTERNAL_CORE);
setup_err_evt(vmst, evt);
break;
}
num_instr++;
@ -213,8 +221,10 @@ uint32_t uvm32_run(uvm32_state_t *vmst, uvm32_evt_t *evt, uint32_t instr_meter)
setup_err_evt(vmst, evt);
return num_instr;
}
}
if (vmst->status == UVM32_STATUS_ENDED) {
evt->typ = UVM32_EVT_END;
return num_instr;