Raymond Toy pushed to branch issue-97-define-ud2-inst at cmucl / cmucl
Commits: 21dd39ea by Raymond Toy at 2021-03-27T11:13:40-07:00 Use INT3 for breakpoints instead of UD2
Since lisp doesn't use INT3 anymore, we know that any INT3 instruction is a breakpoint. Hence, we also don't need to append the breakpoint trap code.
Also need to update function_end_breakpoint_trap to use UD2 instead of INT3. This is needed because we need the trap code to tell lisp this is a function end breakpoint.
Tested this by adding a start breakpoint for kernel:%sqrt. Breakpoint is hit and you can continue. Also tested a function end breakpoint. When the breakpoint is hit, we correctly see the return value(s), and can continue fine.
- - - - -
3 changed files:
- src/code/x86-vm.lisp - src/lisp/x86-arch.c - src/lisp/x86-assem.S
Changes:
===================================== src/code/x86-vm.lisp ===================================== @@ -247,7 +247,7 @@ (vector (make-array length :element-type '(unsigned-byte 8)))) (declare (type (unsigned-byte 8) length) (type (simple-array (unsigned-byte 8) (*)) vector)) - #+nil + #+t (format t "internal-error-args scp ~A: pc ~X len ~D~%" scp pc length) ;; Grab the bytes after length byte, which (copy-from-system-area pc (* vm:byte-bits 4)
===================================== src/lisp/x86-arch.c ===================================== @@ -21,9 +21,7 @@ #include "interr.h" #include "breakpoint.h"
-#if 0 #define BREAKPOINT_INST 0xcc /* INT3 */ -#endif
unsigned long fast_random_state = 1;
@@ -212,9 +210,11 @@ arch_install_breakpoint(void *pc) fprintf(stderr, "arch_install_breakpoint at %p, old code = 0x%lx\n", pc, result);
-#if 0 +#if 1 *(char *) pc = BREAKPOINT_INST; /* x86 INT3 */ +#if 0 *((char *) pc + 1) = trap_Breakpoint; /* Lisp trap code */ +#endif #else *ptr++ = 0x0f; /* UD2 */ *ptr++ = 0x0b; @@ -263,9 +263,11 @@ arch_do_displaced_inst(os_context_t * context, unsigned long orig_inst) * Put the original instruction back. */
-#if 0 +#if 1 *((char *) pc) = orig_inst & 0xff; +#if 0 *((char *) pc + 1) = (orig_inst & 0xff00) >> 8; +#endif #else pc[0] = orig_inst & 0xff; pc[1] = (orig_inst >> 8) & 0xff; @@ -333,7 +335,8 @@ sigill_handler(HANDLER_ARGS) fprintf(stderr, "sigtrap(%d %d %p)\n", signal, CODE(code), os_context); #endif
- if (single_stepping && (signal == SIGILL)) { +#if 0 + if (single_stepping && (signal == SIGTRAP)) { #if 1 fprintf(stderr, "* Single step trap %p\n", single_stepping); #endif @@ -352,9 +355,10 @@ sigill_handler(HANDLER_ARGS) /* * Re-install the breakpoint if possible. */ - fprintf(stderr, "* Reinstall breakpoint at single_stepping %p\n", single_stepping); + fprintf(stderr, "* Maybe reinstall breakpoint for pc %p with single_stepping %p\n", + (void*) SC_PC(os_context), single_stepping);
- if ((int) SC_PC(os_context) >= (int) single_stepping + 3) + if ((int) SC_PC(os_context) < (int) single_stepping + 3) fprintf(stderr, "* Breakpoint not re-install\n"); else { char *ptr = (char *) single_stepping; @@ -372,7 +376,8 @@ sigill_handler(HANDLER_ARGS) single_stepping = NULL; return; } - +#endif + /* This is just for info in case monitor wants to print an approx */ current_control_stack_pointer = (unsigned long *) SC_SP(os_context);
@@ -406,7 +411,7 @@ sigill_handler(HANDLER_ARGS)
switch (trap) { case trap_PendingInterrupt: - DPRINTF(0, (stderr, "<trap Pending Interrupt.>\n")); + DPRINTF(1, (stderr, "<trap Pending Interrupt.>\n")); arch_skip_instruction(os_context); interrupt_handle_pending(os_context); break; @@ -427,7 +432,7 @@ sigill_handler(HANDLER_ARGS)
case trap_Error: case trap_Cerror: - DPRINTF(0, (stderr, "<trap Error %x>\n", CODE(code))); + DPRINTF(1, (stderr, "<trap Error %x>\n", CODE(code))); interrupt_internal_error(signal, code, os_context, CODE(code) == trap_Cerror); break;
@@ -468,7 +473,7 @@ sigill_handler(HANDLER_ARGS) break; #endif default: - DPRINTF(0, + DPRINTF(1, (stderr, "[C--trap default %d %d %p]\n", signal, CODE(code), os_context)); interrupt_handle_now(signal, code, os_context); @@ -514,7 +519,7 @@ sigtrap_handler(HANDLER_ARGS) fprintf(stderr, "* Maybe reinstall breakpoint for pc %p with single_stepping %p\n", (void*) SC_PC(os_context), single_stepping);
- if ((unsigned long) SC_PC(os_context) <= (unsigned long) single_stepping + 3) + if ((unsigned long) SC_PC(os_context) <= (unsigned long) single_stepping) fprintf(stderr, "* Breakpoint not re-install\n"); else { char *ptr = (char *) single_stepping; @@ -532,6 +537,17 @@ sigtrap_handler(HANDLER_ARGS) single_stepping = NULL; return; } +#if 1 + fprintf(stderr, "*C break\n"); +#endif +#if 1 + SC_PC(os_context) -= 1; +#endif + + handle_breakpoint(signal, CODE(code), os_context); +#if 1 + fprintf(stderr, "*C break return\n"); +#endif }
===================================== src/lisp/x86-assem.S ===================================== @@ -286,7 +286,7 @@ multiple_value_return: .globl GNAME(function_end_breakpoint_trap) GNAME(function_end_breakpoint_trap): - INT3 + UD2 .byte trap_FunctionEndBreakpoint hlt # Should never return here.
View it on GitLab: https://gitlab.common-lisp.net/cmucl/cmucl/-/commit/21dd39ea7b8e5bf144ee67f0...
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Raymond Toy