[priv] module now able to load and execute elf binaries

requirements.txt

@@ -0,0 +1 @@
+pyelftools~=0.27

riscemu/priv/ElfLoader.py

@@ -1,9 +1,118 @@
-from ..Executable import Executable, MemorySection, MemoryFlags
+from ..Executable import Executable, MemorySection, MemoryFlags, LoadedExecutable, LoadedMemorySection
+from ..Exceptions import RiscemuBaseException
+from ..helpers import FMT_PARSE, FMT_NONE
+from ..colors import FMT_GREEN, FMT_BOLD
+
+FMT_ELF = FMT_GREEN + FMT_BOLD
+
+from .Exceptions import *
+
+from dataclasses import dataclass
+
+from typing import List, Dict, Union
+
+from elftools.elf.elffile import ELFFile
+from elftools.elf.sections import Section, SymbolTableSection
+
+from ..decoder import decode
 
 # This requires pyelftools package!
 
-class ElfExecutable(Executable):
-    def __init__(self, name):
-        from elftools.elf.elffile import ELFFile
+INCLUDE_SEC = ('.text', '.stack', '.bss')
+
+
+class ElfExecutable:
+    sections: List['ElfLoadedMemorySection']
+    sections_by_name: Dict[str, 'ElfLoadedMemorySection']
+    symbols: Dict[str, int]
+    run_ptr: int
+
+    def __init__(self, name: str):
+        self.sections = list()
+        self.sections_by_name = dict()
+        self.symbols = dict()
+
+        with open(name, 'rb') as f:
+            print(FMT_ELF + "[ElfLoader] Loading elf executable from: {}".format(name) + FMT_NONE)
+            self._read_elf(ELFFile(f))
+
+    def _read_elf(self, elf: ELFFile):
+        if not elf.header.e_machine == 'EM_RISCV':
+            raise InvalidElfException("Not a RISC-V elf file!")
+        if not elf.header.e_ident.EI_CLASS == 'ELFCLASS32':
+            raise InvalidElfException("Only 32bit executables are supported!")
+
+        self.run_ptr = elf.header.e_entry;
+
+        for sec in elf.iter_sections():
+            if isinstance(sec, SymbolTableSection):
+                self._parse_symtab(sec)
+                continue
+
+            if sec.name not in INCLUDE_SEC:
+                continue
+
+            sec_ = self._lms_from_elf_sec(sec, 'kernel')
+            self.sections.append(sec_)
+            self.sections_by_name[sec.name] = sec_
+
+    def _lms_from_elf_sec(self, sec: Section, owner: str):
+        is_code = sec.name in ('.text',)
+        data = sec.data()
+        flags = MemoryFlags(is_code, is_code)
+        print(FMT_ELF + "[ElfLoader] Section {} at: {:X}".format(sec.name, sec.header.sh_addr) + FMT_NONE)
+        return ElfLoadedMemorySection(
+            sec.name,
+            sec.header.sh_addr,
+            sec.data_size,
+            data,
+            flags,
+            owner
+        )
+
+    def _parse_symtab(self, symtab: SymbolTableSection):
+        self.symbols = {
+            sym.name: sym.entry.st_value for sym in symtab.iter_symbols() if sym.name
+        }
+
+    def load_user_elf(self, name: str):
+        pass
+
+
+class InvalidElfException(RiscemuBaseException):
+    def __init__(self, msg: str):
+        super().__init__()
+        self.msg = msg
+
+    def message(self):
+        return FMT_PARSE + "{}(\"{}\")".format(self.__class__.__name__, self.msg) + FMT_NONE
+
+
+@dataclass(frozen=True)
+class ElfInstruction:
+    name: str
+    args: List[Union[int, str]]
+
+    def get_imm(self, num: int):
+        return self.args[-1]
+
+    def get_imm_reg(self, num: int):
+        return self.args[-1], self.args[-2]
+
+    def get_reg(self, num: int):
+        return self.args[num]
+
+    def __repr__(self):
+        return "{:<8} {}".format(
+            self.name,
+            ", ".join(map(str, self.args))
+        )
 
-        with open(f)
+class ElfLoadedMemorySection(LoadedMemorySection):
+    def read_instruction(self, offset):
+        if not self.flags.executable:
+            print(FMT_PARSE + "Reading instruction from non-executable memory!" + FMT_NONE)
+            raise InstructionAccessFault(offset + self.base)
+        if offset % 4 != 0:
+            raise InstructionAddressMisalignedTrap(offset + self.base)
+        return ElfInstruction(*decode(self.content[offset:offset + 4]))

riscemu/priv/Exceptions.py

@@ -21,3 +21,15 @@ class CpuTrap(BaseException):
 class IllegalInstructionTrap(CpuTrap):
     def __init__(self):
         super().__init__(0, 2, 0)
+
+
+class InstructionAddressMisalignedTrap(CpuTrap):
+    def __init__(self, addr: int):
+        super().__init__(0, 0, addr)
+
+
+class InstructionAccessFault(CpuTrap):
+    def __init__(self, addr: int):
+        super().__init__(0, 1, addr)
+
+

riscemu/priv/PrivCPU.py

@@ -11,6 +11,9 @@ from .Exceptions import *
 from .CSR import CSR
 from .PrivRV32I import PrivRV32I
 from ..instructions.RV32M import RV32M
+from .PrivMMU import PrivMMU
+from .ElfLoader import ElfExecutable
+from .privmodes import PrivModes
 
 from collections import defaultdict
 
@@ -20,13 +23,6 @@ if typing.TYPE_CHECKING:
     from riscemu import Executable, LoadedExecutable, LoadedInstruction
     from riscemu.instructions.InstructionSet import InstructionSet
 
-
-class PrivModes(IntEnum):
-    USER = 0
-    SUPER = 1
-    MACHINE = 3
-
-
 class PrivCPU(CPU):
     """
     This is a CPU that has different modes, instruction sets and registers.
@@ -38,7 +34,7 @@ class PrivCPU(CPU):
 
     csr: CSR
 
-    INS_XLEN = 1
+    INS_XLEN = 4
     """
     Size of an instruction in memory. Should be 4, but since our loading code is shit, instruction take up 
     the equivalent of "1 byte" (this is actually impossible)
@@ -48,12 +44,18 @@ class PrivCPU(CPU):
         super().__init__(conf, [PrivRV32I, RV32M])
         self.mode: PrivModes = PrivModes.MACHINE
 
+        exec = ElfExecutable('kernel')
+        self.mmu = PrivMMU(exec)
+        self.pc = exec.run_ptr
+        self.syscall_int = None
+
         # set up CSR
         self.csr = CSR()
         # TODO: Actually populate the CSR with real data (vendorID, heartID, machine implementation etc)
         self.csr.set('mhartid', 0)  # core id
         self.csr.set('mimpid', 1)  # implementation id
-        self.csr.set('misa', ())  # available ISA
+        # TODO: set correct misa
+        self.csr.set('misa', 1)  # available ISA
 
     def _run(self, verbose=False):
         if self.pc <= 0:
@@ -66,7 +68,7 @@ class PrivCPU(CPU):
                     ins = self.mmu.read_ins(self.pc)
                     if verbose:
                         print(FMT_CPU + "   Running 0x{:08X}:{} {}".format(self.pc, FMT_NONE, ins))
-                    self.pc += 1
+                    self.pc += self.INS_XLEN
                     self.run_instruction(ins)
                 except CpuTrap as trap:
                     mie = self.csr.get_mstatus('mie')
@@ -97,8 +99,6 @@ class PrivCPU(CPU):
                     else:
                         # standard mode
                         self.pc = (mtvec >> 2)
-
-
         except RiscemuBaseException as ex:
             if not isinstance(ex, LaunchDebuggerException):
                 print(FMT_ERROR + "[CPU] excpetion caught at 0x{:08X}: {}:".format(self.pc - 1, ins) + FMT_NONE)
@@ -119,3 +119,17 @@ class PrivCPU(CPU):
         else:
             print()
             print(FMT_CPU + "Program stopped without exiting - perhaps you stopped the debugger?" + FMT_NONE)
+
+    def load(self, e: riscemu.Executable):
+        raise NotImplementedError("Not supported!")
+
+    def run_loaded(self, le: 'riscemu.LoadedExecutable'):
+        raise NotImplementedError("Not supported!")
+
+    def get_tokenizer(self, tokenizer_input):
+        raise NotImplementedError("Not supported!")
+
+    def run(self):
+        print(FMT_CPU + '[CPU] Started running from 0x{:08X} ({})'.format(self.pc, "kernel") + FMT_NONE)
+        self._run(True)
+

riscemu/priv/PrivMMU.py

@@ -0,0 +1,25 @@
+from ..MMU import *
+
+import typing
+
+from .ElfLoader import ElfExecutable
+
+class PrivMMU(MMU):
+    def __init__(self, elf: ElfExecutable):
+        super(PrivMMU, self).__init__(conf=RunConfig())
+
+        self.binaries.append(elf)
+        for sec in elf.sections:
+            self.sections.append(sec)
+
+    def load_bin(self, exe: Executable) -> LoadedExecutable:
+        raise NotImplementedError("This is a privMMU, it's initialized with a single ElfExecutable!")
+
+    def allocate_section(self, name: str, req_size: int, flag: MemoryFlags):
+        raise NotImplementedError("Not supported!")
+
+
+
+
+
+

riscemu/priv/PrivRV32I.py

@@ -4,24 +4,28 @@ RiscEmu (c) 2021 Anton Lydike
 SPDX-License-Identifier: MIT
 """
 
-from riscemu.instructions.RV32I import *
+from ..instructions.RV32I import *
 from ..Exceptions import INS_NOT_IMPLEMENTED
-from riscemu.priv.PrivCPU import PrivModes, PrivCPU
 from .Exceptions import *
+from .privmodes import PrivModes
+import typing
+
+if typing.TYPE_CHECKING:
+    from riscemu.priv.PrivCPU import PrivCPU
 
 
 class PrivRV32I(RV32I):
-    cpu: PrivCPU
+    cpu: 'PrivCPU'
     """
     This is an extension of RV32I, written for the PrivCPU class
     """
 
     def instruction_csrrw(self, ins: 'LoadedInstruction'):
-        rd, off, rs = self.parse_crs_ins(ins)
+        rd, rs, ind = self.parse_crs_ins(ins)
         if rd != 'zero':
-            old_val = int_from_bytes(self.cpu.csr.read(off, 4))
+            old_val = int_from_bytes(self.cpu.csr[ind])
             self.regs.set(rd, old_val)
-        self.cpu.csr.write(off, 4, int_to_bytes(rs))
+        self.cpu.csr.set(ind, rs)
 
     def instruction_csrrs(self, ins: 'LoadedInstruction'):
         INS_NOT_IMPLEMENTED(ins)
@@ -63,17 +67,64 @@ class PrivRV32I(RV32I):
         Overwrite the scall from userspace RV32I
         """
         if self.cpu.mode == PrivModes.USER:
-            raise CpuTrap(0, 8)         # ecall from U mode
+            raise CpuTrap(0, 8)  # ecall from U mode
         elif self.cpu.mode == PrivModes.SUPER:
-            raise CpuTrap(0, 9)         # ecall from S mode - should not happen
+            raise CpuTrap(0, 9)  # ecall from S mode - should not happen
         elif self.cpu.mode == PrivModes.MACHINE:
-            raise CpuTrap(0, 11)        # ecall from M mode
-
-
-
-
-
+            raise CpuTrap(0, 11)  # ecall from M mode
+
+    def instruction_beq(self, ins: 'LoadedInstruction'):
+        rs1, rs2, dst = self.parse_rs_rs_imm(ins)
+        if rs1 == rs2:
+            self.pc += dst
+
+    def instruction_bne(self, ins: 'LoadedInstruction'):
+        rs1, rs2, dst = self.parse_rs_rs_imm(ins)
+        if rs1 != rs2:
+            self.pc += dst
+
+    def instruction_blt(self, ins: 'LoadedInstruction'):
+        rs1, rs2, dst = self.parse_rs_rs_imm(ins)
+        if rs1 < rs2:
+            self.pc += dst
+
+    def instruction_bge(self, ins: 'LoadedInstruction'):
+        rs1, rs2, dst = self.parse_rs_rs_imm(ins)
+        if rs1 >= rs2:
+            self.pc += dst
+
+    def instruction_bltu(self, ins: 'LoadedInstruction'):
+        rs1, rs2, dst = self.parse_rs_rs_imm(ins, signed=False)
+        if rs1 < rs2:
+            self.pc += dst
+
+    def instruction_bgeu(self, ins: 'LoadedInstruction'):
+        rs1, rs2, dst = self.parse_rs_rs_imm(ins, signed=False)
+        if rs1 >= rs2:
+            self.pc += dst
+
+    # technically deprecated
+    def instruction_j(self, ins: 'LoadedInstruction'):
+        raise NotImplementedError("Should never be reached!")
+
+    def instruction_jal(self, ins: 'LoadedInstruction'):
+        ASSERT_LEN(ins.args, 2)
+        reg = ins.get_reg(0)
+        addr = ins.get_imm(1)
+        self.regs.set(reg, self.pc)
+        self.pc += addr
+
+    def instruction_jalr(self, ins: 'LoadedInstruction'):
+        ASSERT_LEN(ins.args, 3)
+        rd, rs, imm = self.parse_rd_rs_imm(ins)
+        self.regs.set(rd, self.pc)
+        self.pc = rs + imm
 
     def parse_crs_ins(self, ins: 'LoadedInstruction'):
         ASSERT_LEN(ins.args, 3)
-        return ins.get_reg(0), ins.get_imm(1), self.get_reg_content(ins, 2)
+        return ins.get_reg(0), self.get_reg_content(ins, 1), ins.get_imm(2)
+
+    def parse_mem_ins(self, ins: 'LoadedInstruction') -> Tuple[str, int]:
+        ASSERT_LEN(ins.args, 3)
+        print("dop")
+        return ins.get_reg(1), self.get_reg_content(ins, 0) + ins.get_imm(2)

riscemu/priv/__main__.py

@@ -1,4 +1,4 @@
-from .PrivCPU import *
+from .PrivCPU import PrivCPU, RunConfig
 
 from ..Tokenizer import RiscVInput
 from ..ExecutableParser import ExecutableParser
@@ -11,17 +11,6 @@ if __name__ == '__main__':
 
     cpu = PrivCPU(RunConfig())
 
-    try:
-        loaded_exe = None
-        for file in files:
-            tk = cpu.get_tokenizer(RiscVInput.from_file(file))
-            tk.tokenize()
-            loaded_exe = cpu.load(ExecutableParser(tk).parse())
-        # run the last loaded executable
-        cpu.run_loaded(loaded_exe)
-    except RiscemuBaseException as e:
-        print("Error while parsing: {}".format(e.message()))
-        import traceback
-
-        traceback.print_exception(type(e), e, e.__traceback__)
-        sys.exit(1)
+    cpu.run()
+
+

riscemu/priv/privmodes.py

@@ -0,0 +1,7 @@
+from enum import IntEnum
+
+
+class PrivModes(IntEnum):
+    USER = 0
+    SUPER = 1
+    MACHINE = 3