diff options
| -rw-r--r-- | Python/jit.c | 52 | ||||
| -rw-r--r-- | Tools/jit/_stencils.py | 7 | ||||
| -rw-r--r-- | Tools/jit/_targets.py | 2 |
3 files changed, 27 insertions, 34 deletions
diff --git a/Python/jit.c b/Python/jit.c index dae2516..f67d641 100644 --- a/Python/jit.c +++ b/Python/jit.c @@ -112,26 +112,6 @@ mark_executable(unsigned char *memory, size_t size) return 0; } -static int -mark_readable(unsigned char *memory, size_t size) -{ - if (size == 0) { - return 0; - } - assert(size % get_page_size() == 0); -#ifdef MS_WINDOWS - DWORD old; - int failed = !VirtualProtect(memory, size, PAGE_READONLY, &old); -#else - int failed = mprotect(memory, size, PROT_READ); -#endif - if (failed) { - jit_error("unable to protect readable memory"); - return -1; - } - return 0; -} - // JIT compiler stuff: ///////////////////////////////////////////////////////// // Warning! AArch64 requires you to get your hands dirty. These are your gloves: @@ -409,12 +389,14 @@ _PyJIT_Compile(_PyExecutorObject *executor, const _PyUOpInstruction *trace, size code_size += group->code.body_size; data_size += group->data.body_size; } - // Round up to the nearest page (code and data need separate pages): + code_size += stencil_groups[_FATAL_ERROR].code.body_size; + data_size += stencil_groups[_FATAL_ERROR].data.body_size; + // Round up to the nearest page: size_t page_size = get_page_size(); assert((page_size & (page_size - 1)) == 0); - code_size += page_size - (code_size & (page_size - 1)); - data_size += page_size - (data_size & (page_size - 1)); - unsigned char *memory = jit_alloc(code_size + data_size); + size_t padding = page_size - ((code_size + data_size) & (page_size - 1)); + size_t total_size = code_size + data_size + padding; + unsigned char *memory = jit_alloc(total_size); if (memory == NULL) { return -1; } @@ -444,14 +426,26 @@ _PyJIT_Compile(_PyExecutorObject *executor, const _PyUOpInstruction *trace, size code += group->code.body_size; data += group->data.body_size; } - if (mark_executable(memory, code_size) || - mark_readable(memory + code_size, data_size)) - { - jit_free(memory, code_size + data_size); + // Protect against accidental buffer overrun into data: + const StencilGroup *group = &stencil_groups[_FATAL_ERROR]; + uint64_t patches[] = GET_PATCHES(); + patches[HoleValue_CODE] = (uint64_t)code; + patches[HoleValue_CONTINUE] = (uint64_t)code; + patches[HoleValue_DATA] = (uint64_t)data; + patches[HoleValue_EXECUTOR] = (uint64_t)executor; + patches[HoleValue_TOP] = (uint64_t)code; + patches[HoleValue_ZERO] = 0; + emit(group, patches); + code += group->code.body_size; + data += group->data.body_size; + assert(code == memory + code_size); + assert(data == memory + code_size + data_size); + if (mark_executable(memory, total_size)) { + jit_free(memory, total_size); return -1; } executor->jit_code = memory; - executor->jit_size = code_size + data_size; + executor->jit_size = total_size; return 0; } diff --git a/Tools/jit/_stencils.py b/Tools/jit/_stencils.py index 78c566d..05c4ce8 100644 --- a/Tools/jit/_stencils.py +++ b/Tools/jit/_stencils.py @@ -124,7 +124,7 @@ class Stencil: ): self.holes.append(hole.replace(offset=base + 4 * i, kind=kind)) - def remove_jump(self) -> None: + def remove_jump(self, *, alignment: int = 1) -> None: """Remove a zero-length continuation jump, if it exists.""" hole = max(self.holes, key=lambda hole: hole.offset) match hole: @@ -170,7 +170,7 @@ class Stencil: offset -= 2 case _: return - if self.body[offset:] == jump: + if self.body[offset:] == jump and offset % alignment == 0: self.body = self.body[:offset] self.holes.remove(hole) @@ -199,9 +199,8 @@ class StencilGroup: ): self.code.pad(alignment) self.code.emit_aarch64_trampoline(hole) - self.code.pad(alignment) self.code.holes.remove(hole) - self.code.remove_jump() + self.code.remove_jump(alignment=alignment) self.code.pad(alignment) self.data.pad(8) for stencil in [self.code, self.data]: diff --git a/Tools/jit/_targets.py b/Tools/jit/_targets.py index 417fdb5..66db358 100644 --- a/Tools/jit/_targets.py +++ b/Tools/jit/_targets.py @@ -89,7 +89,7 @@ class _Target(typing.Generic[_S, _R]): if group.data.body: line = f"0: {str(bytes(group.data.body)).removeprefix('b')}" group.data.disassembly.append(line) - group.process_relocations() + group.process_relocations(alignment=self.alignment) return group def _handle_section(self, section: _S, group: _stencils.StencilGroup) -> None: |