1.0.36.9: UD2-BREAKPOINTS feature for x86oid systems

[sbcl.git] / src / runtime / x86-arch.c

diff --git a/src/runtime/x86-arch.c b/src/runtime/x86-arch.c
index b9b5250..b000e0f 100644 (file)
--- a/src/runtime/x86-arch.c
+++ b/src/runtime/x86-arch.c
@@ -30,6 +30,13 @@
 #include "genesis/symbol.h"
 
 #define BREAKPOINT_INST 0xcc    /* INT3 */
+#define UD2_INST 0x0b0f         /* UD2 */
+
+#ifndef LISP_FEATURE_UD2_BREAKPOINTS
+#define BREAKPOINT_WIDTH 1
+#else
+#define BREAKPOINT_WIDTH 2
+#endif
 
 unsigned long fast_random_state = 1;
 
@@ -158,8 +165,14 @@ arch_install_breakpoint(void *pc)
 {
     unsigned int result = *(unsigned int*)pc;
 
+#ifndef LISP_FEATURE_UD2_BREAKPOINTS
     *(char*)pc = BREAKPOINT_INST;               /* x86 INT3       */
     *((char*)pc+1) = trap_Breakpoint;           /* Lisp trap code */
+#else
+    *(char*)pc = UD2_INST & 0xff;
+    *((char*)pc+1) = UD2_INST >> 8;
+    *((char*)pc+2) = trap_Breakpoint;
+#endif
 
     return result;
 }
@@ -169,6 +182,9 @@ arch_remove_breakpoint(void *pc, unsigned int orig_inst)
 {
     *((char *)pc) = orig_inst & 0xff;
     *((char *)pc + 1) = (orig_inst & 0xff00) >> 8;
+#if BREAKPOINT_WIDTH > 1
+    *((char *)pc + 2) = (orig_inst & 0xff0000) >> 16;
+#endif
 }
 \f
 /* When single stepping, single_stepping holds the original instruction
@@ -186,8 +202,7 @@ arch_do_displaced_inst(os_context_t *context, unsigned int orig_inst)
     unsigned int *pc = (unsigned int*)(*os_context_pc_addr(context));
 
     /* Put the original instruction back. */
-    *((char *)pc) = orig_inst & 0xff;
-    *((char *)pc + 1) = (orig_inst & 0xff00) >> 8;
+    arch_remove_breakpoint(pc, orig_inst);
 
 #ifdef CANNOT_GET_TO_SINGLE_STEP_FLAG
     /* Install helper instructions for the single step:
@@ -222,11 +237,13 @@ restore_breakpoint_from_single_step(os_context_t * context)
     *context_eflags_addr(context) &= ~0x100;
 #endif
     /* Re-install the breakpoint if possible. */
-    if (*os_context_pc_addr(context) == (int)single_stepping + 1) {
+    if (((char *)*os_context_pc_addr(context) >
+         (char *)single_stepping) &&
+        ((char *)*os_context_pc_addr(context) <=
+         (char *)single_stepping + BREAKPOINT_WIDTH)) {
         fprintf(stderr, "warning: couldn't reinstall breakpoint\n");
     } else {
-        *((char *)single_stepping) = BREAKPOINT_INST;       /* x86 INT3 */
-        *((char *)single_stepping+1) = trap_Breakpoint;
+        arch_install_breakpoint(single_stepping);
     }
 
     single_stepping = NULL;
@@ -236,14 +253,14 @@ restore_breakpoint_from_single_step(os_context_t * context)
 void
 arch_handle_breakpoint(os_context_t *context)
 {
-    --*os_context_pc_addr(context);
+    *os_context_pc_addr(context) -= BREAKPOINT_WIDTH;
     handle_breakpoint(context);
 }
 
 void
 arch_handle_fun_end_breakpoint(os_context_t *context)
 {
-    --*os_context_pc_addr(context);
+    *os_context_pc_addr(context) -= BREAKPOINT_WIDTH;
     *os_context_pc_addr(context) =
         (int)handle_fun_end_breakpoint(context);
 }
@@ -263,7 +280,7 @@ sigtrap_handler(int signal, siginfo_t *info, os_context_t *context)
 {
     unsigned int trap;
 
-    if (single_stepping && (signal==SIGTRAP)) {
+    if (single_stepping) {
         restore_breakpoint_from_single_step(context);
         return;
     }
@@ -297,8 +314,8 @@ sigill_handler(int signal, siginfo_t *siginfo, os_context_t *context) {
     /* Triggering SIGTRAP using int3 is unreliable on OS X/x86, so
      * we need to use illegal instructions for traps.
      */
-#if defined(LISP_FEATURE_DARWIN) && !defined(LISP_FEATURE_MACH_EXCEPTION_HANDLER)
-    if (*((unsigned short *)*os_context_pc_addr(context)) == 0x0b0f) {
+#if defined(LISP_FEATURE_UD2_BREAKPOINTS) && !defined(LISP_FEATURE_MACH_EXCEPTION_HANDLER)
+    if (*((unsigned short *)*os_context_pc_addr(context)) == UD2_INST) {
         *os_context_pc_addr(context) += 2;
         return sigtrap_handler(signal, siginfo, context);
     }