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py: Add mp_pending_exception global variable, for VM soft interrupt.

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This allows to implement KeyboardInterrupt on unix, and a much safer
ctrl-C in stmhal port.  First ctrl-C is a soft one, with hope that VM
will notice it; second ctrl-C is a hard one that kills anything (for
both unix and stmhal).

One needs to check for a pending exception in the VM only for jump
opcodes.  Others can't produce an infinite loop (infinite recursion is
caught by stack check).
This commit is contained in:
Damien George 2014-10-25 18:19:55 +01:00
parent d7353fe6fe
commit 124df6f8d0
10 changed files with 71 additions and 14 deletions
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1
py/obj.h
View File

@ -330,6 +330,7 @@ extern const mp_obj_type_t mp_type_GeneratorExit;
extern const mp_obj_type_t mp_type_ImportError;
extern const mp_obj_type_t mp_type_IndentationError;
extern const mp_obj_type_t mp_type_IndexError;
extern const mp_obj_type_t mp_type_KeyboardInterrupt;
extern const mp_obj_type_t mp_type_KeyError;
extern const mp_obj_type_t mp_type_LookupError;
extern const mp_obj_type_t mp_type_MemoryError;

2
py/objexcept.c
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@ -211,7 +211,7 @@ const mp_obj_type_t mp_type_ ## exc_name = { \
// http://docs.python.org/3/library/exceptions.html
MP_DEFINE_EXCEPTION_BASE(BaseException)
MP_DEFINE_EXCEPTION(SystemExit, BaseException)
//MP_DEFINE_EXCEPTION(KeyboardInterrupt, BaseException)
MP_DEFINE_EXCEPTION(KeyboardInterrupt, BaseException)
MP_DEFINE_EXCEPTION(GeneratorExit, BaseException)
MP_DEFINE_EXCEPTION(Exception, BaseException)
MP_DEFINE_EXCEPTION_BASE(Exception)

1
py/qstrdefs.h
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@ -108,6 +108,7 @@ Q(GeneratorExit)
Q(ImportError)
Q(IndentationError)
Q(IndexError)
Q(KeyboardInterrupt)
Q(KeyError)
Q(LookupError)
Q(MemoryError)

6
py/runtime.c
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@ -62,6 +62,9 @@
#define DEBUG_OP_printf(...) (void)0
#endif
// pending exception object (MP_OBJ_NULL if not pending)
mp_obj_t mp_pending_exception;
// locals and globals need to be pointers because they can be the same in outer module scope
STATIC mp_obj_dict_t *dict_locals;
STATIC mp_obj_dict_t *dict_globals;
@ -79,6 +82,9 @@ void mp_init(void) {
qstr_init();
mp_stack_ctrl_init();
// no pending exceptions to start with
mp_pending_exception = MP_OBJ_NULL;
#if MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
mp_init_emergency_exception_buf();
#endif

1
py/runtime.h
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@ -116,6 +116,7 @@ mp_obj_t mp_convert_native_to_obj(mp_uint_t val, mp_uint_t type);
mp_obj_t mp_native_call_function_n_kw(mp_obj_t fun_in, mp_uint_t n_args_kw, const mp_obj_t *args);
NORETURN void mp_native_raise(mp_obj_t o);
extern mp_obj_t mp_pending_exception;
extern struct _mp_obj_list_t mp_sys_path_obj;
extern struct _mp_obj_list_t mp_sys_argv_obj;
#define mp_sys_path ((mp_obj_t)&mp_sys_path_obj)

23
py/vm.c
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@ -110,10 +110,12 @@ mp_vm_return_kind_t mp_execute_bytecode(mp_code_state *code_state, volatile mp_o
code_state->ip = ip; \
goto *entry_table[*ip++]; \
} while(0)
#define DISPATCH_WITH_PEND_EXC_CHECK() goto pending_exception_check
#define ENTRY(op) entry_##op
#define ENTRY_DEFAULT entry_default
#else
#define DISPATCH() break
#define DISPATCH_WITH_PEND_EXC_CHECK() goto pending_exception_check
#define ENTRY(op) case op
#define ENTRY_DEFAULT default
#endif
@ -372,21 +374,21 @@ dispatch_loop:
ENTRY(MP_BC_JUMP):
DECODE_SLABEL;
ip += unum;
DISPATCH();
DISPATCH_WITH_PEND_EXC_CHECK();
ENTRY(MP_BC_POP_JUMP_IF_TRUE):
DECODE_SLABEL;
if (mp_obj_is_true(POP())) {
ip += unum;
}
DISPATCH();
DISPATCH_WITH_PEND_EXC_CHECK();
ENTRY(MP_BC_POP_JUMP_IF_FALSE):
DECODE_SLABEL;
if (!mp_obj_is_true(POP())) {
ip += unum;
}
DISPATCH();
DISPATCH_WITH_PEND_EXC_CHECK();
ENTRY(MP_BC_JUMP_IF_TRUE_OR_POP):
DECODE_SLABEL;
@ -395,7 +397,7 @@ dispatch_loop:
} else {
sp--;
}
DISPATCH();
DISPATCH_WITH_PEND_EXC_CHECK();
ENTRY(MP_BC_JUMP_IF_FALSE_OR_POP):
DECODE_SLABEL;
@ -404,7 +406,7 @@ dispatch_loop:
} else {
ip += unum;
}
DISPATCH();
DISPATCH_WITH_PEND_EXC_CHECK();
ENTRY(MP_BC_SETUP_WITH): {
mp_obj_t obj = TOP();
@ -502,7 +504,7 @@ unwind_jump:
if (unum != 0) {
sp--;
}
DISPATCH();
DISPATCH_WITH_PEND_EXC_CHECK();
// matched against: POP_BLOCK or POP_EXCEPT (anything else?)
ENTRY(MP_BC_SETUP_EXCEPT):
@ -909,6 +911,15 @@ yield:
#if !MICROPY_OPT_COMPUTED_GOTO
} // switch
#endif
pending_exception_check:
if (mp_pending_exception != MP_OBJ_NULL) {
mp_obj_t obj = mp_pending_exception;
mp_pending_exception = MP_OBJ_NULL;
RAISE(obj);
}
DISPATCH();
} // for loop
} else {

17
stmhal/pendsv.c
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@ -31,6 +31,7 @@
#include "misc.h"
#include "qstr.h"
#include "obj.h"
#include "runtime.h"
#include "pendsv.h"
static void *pendsv_object = NULL;
@ -40,13 +41,23 @@ void pendsv_init(void) {
HAL_NVIC_SetPriority(PendSV_IRQn, 0xf, 0xf);
}
// call this function to raise a pending exception during an interrupt
// it will wait until all interrupts are finished then raise the given
// exception object using nlr_jump in the context of the top-level thread
// Call this function to raise a pending exception during an interrupt.
// It will first try to raise the exception "softly" by setting the
// mp_pending_exception variable and hoping that the VM will notice it.
// If this function is called a second time (ie with the mp_pending_exception
// variable already set) then it will force the exception by using the hardware
// PENDSV feature. This will wait until all interrupts are finished then raise
// the given exception object using nlr_jump in the context of the top-level
// thread.
void pendsv_nlr_jump(void *o) {
if (mp_pending_exception == MP_OBJ_NULL) {
mp_pending_exception = o;
} else {
mp_pending_exception = MP_OBJ_NULL;
pendsv_object = o;
SCB->ICSR = SCB_ICSR_PENDSVSET_Msk;
}
}
// since we play tricks with the stack, the compiler must not generate a
// prelude for this function

2
stmhal/usb.c
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@ -50,7 +50,7 @@ STATIC mp_obj_t mp_const_vcp_interrupt = MP_OBJ_NULL;
void pyb_usb_init0(void) {
// create an exception object for interrupting by VCP
mp_const_vcp_interrupt = mp_obj_new_exception_msg(&mp_type_OSError, "VCPInterrupt");
mp_const_vcp_interrupt = mp_obj_new_exception(&mp_type_KeyboardInterrupt);
USBD_CDC_SetInterrupt(VCP_CHAR_NONE, mp_const_vcp_interrupt);
}

1
stmhal/usbd_cdc_interface.c
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@ -374,7 +374,6 @@ static int8_t CDC_Itf_Receive(uint8_t* Buf, uint32_t *Len) {
if (char_found) {
// raise exception when interrupts are finished
user_interrupt_char = VCP_CHAR_NONE;
pendsv_nlr_jump(user_interrupt_data);
}

27
unix/main.c
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@ -34,6 +34,7 @@
#include <sys/stat.h>
#include <sys/types.h>
#include <errno.h>
#include <signal.h>
#include "mpconfig.h"
#include "nlr.h"
@ -64,6 +65,20 @@ mp_uint_t mp_verbose_flag = 0;
long heap_size = 128*1024 * (sizeof(mp_uint_t) / 4);
#endif
STATIC mp_obj_t keyboard_interrupt_obj;
STATIC void sighandler(int signum) {
if (signum == SIGINT) {
mp_obj_exception_clear_traceback(keyboard_interrupt_obj);
mp_pending_exception = keyboard_interrupt_obj;
// disable our handler so next we really die
struct sigaction sa;
sa.sa_handler = SIG_DFL;
sigemptyset(&sa.sa_mask);
sigaction(SIGINT, &sa, NULL);
}
}
#define FORCED_EXIT (0x100)
// returns standard error codes: 0 for success, 1 for all other errors
// if FORCED_EXIT bit is set then script raised SystemExit and the
@ -119,14 +134,23 @@ STATIC int execute_from_lexer(mp_lexer_t *lex, mp_parse_input_kind_t input_kind,
return 0;
}
// enable signal handler
struct sigaction sa;
sa.sa_handler = sighandler;
sigemptyset(&sa.sa_mask);
sigaction(SIGINT, &sa, NULL);
sa.sa_handler = SIG_DFL;
// execute it
nlr_buf_t nlr;
if (nlr_push(&nlr) == 0) {
mp_call_function_0(module_fun);
sigaction(SIGINT, &sa, NULL);
nlr_pop();
return 0;
} else {
// uncaught exception
sigaction(SIGINT, &sa, NULL);
// check for SystemExit
mp_obj_t exc = (mp_obj_t)nlr.ret_val;
if (mp_obj_is_subclass_fast(mp_obj_get_type(exc), &mp_type_SystemExit)) {
@ -305,6 +329,9 @@ int main(int argc, char **argv) {
mp_init();
// create keyboard interrupt object
keyboard_interrupt_obj = mp_obj_new_exception(&mp_type_KeyboardInterrupt);
char *home = getenv("HOME");
char *path = getenv("MICROPYPATH");
if (path == NULL) {