Blackfin arch: Fix bug - skip single step in high priority interrupt handler instead...

Skip single step if event priority of current instruction is higher than
that of the first instruction, from which gdb starts single step.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

diff --git a/arch/blackfin/kernel/kgdb.c b/arch/blackfin/kernel/kgdb.c
index a9c15515bfd7347dd62fcc536c8b2194fe5a4c25..a1f9641a6425d6158ebf21f4a71f4df867fd44ea 100644 (file)
--- a/arch/blackfin/kernel/kgdb.c
+++ b/arch/blackfin/kernel/kgdb.c
@@ -203,6 +203,8 @@ struct hw_breakpoint {
 
 int kgdb_arch_init(void)
 {
+       debugger_step = 0;
+
        kgdb_remove_all_hw_break();
        return 0;
 }
@@ -368,6 +370,7 @@ int kgdb_arch_handle_exception(int exceptionVector, int signo,
        char *ptr;
        int newPC;
        int wp_status;
+       int i;
 
        switch (remcom_in_buffer[0]) {
        case 'c':
@@ -392,7 +395,18 @@ int kgdb_arch_handle_exception(int exceptionVector, int signo,
                /* set the trace bit if we're stepping */
                if (remcom_in_buffer[0] == 's') {
                        linux_regs->syscfg |= 0x1;
-                       debugger_step = 1;
+                       debugger_step = linux_regs->ipend;
+                       debugger_step >>= 6;
+                       for (i = 10; i > 0; i--, debugger_step >>= 1)
+                               if (debugger_step & 1)
+                                       break;
+                       /* i indicate event priority of current stopped instruction
+                        * user space instruction is 0, IVG15 is 1, IVTMR is 10.
+                        * debugger_step > 0 means in single step mode
+                        */
+                       debugger_step = i + 1;
+               } else {
+                       debugger_step = 0;
                }
 
                wp_status = bfin_read_WPSTAT();

diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S
index 038f70e0be65cb4adcb1ada19b07f6d75eba7d8b..eceb484d90f9da1144a1c1afca1e019f29a3f672 100644 (file)
--- a/arch/blackfin/mach-common/entry.S
+++ b/arch/blackfin/mach-common/entry.S
@@ -158,23 +158,45 @@ ENTRY(_ex_single_step)
        cc = r7 == r6;
        if cc jump _bfin_return_from_exception;
 
+       /* Don't do single step in hardware exception handler */
+        p5.l = lo(IPEND);
+        p5.h = hi(IPEND);
+       r6 = [p5];
+       cc = bittst(r6, 5);
+       if cc jump _bfin_return_from_exception;
+
+#ifdef CONFIG_KGDB
+       /* skip single step if current interrupt priority is higher than
+        * that of the first instruction, from which gdb starts single step */
+       r6 >>= 6;
+       r7 = 10;
+.Lfind_priority_start:
+       cc = bittst(r6, 0);
+       if cc jump .Lfind_priority_done;
+       r6 >>= 1;
+       r7 += -1;
+       cc = r7 == 0;
+       if cc jump .Lfind_priority_done;
+       jump.s .Lfind_priority_start;
+.Lfind_priority_done:
+       p4.l = _debugger_step;
+       p4.h = _debugger_step;
+       r6 = [p4];
+       cc = r6 == 0;
+       if cc jump .Ldo_single_step;
+       r6 += -1;
+       cc = r6 < r7;
+       if cc jump _bfin_return_from_exception;
+.Ldo_single_step:
+#endif
+
        /* If we were in user mode, do the single step normally.  */
-       p5.l = lo(IPEND);
-       p5.h = hi(IPEND);
        r6 = [p5];
        r7 = 0xffe0 (z);
        r7 = r7 & r6;
        cc = r7 == 0;
-       if !cc jump 1f;
-
-       /* Single stepping only a single instruction, so clear the trace
-        * bit here.  */
-       r7 = syscfg;
-       bitclr (r7, 0);
-       syscfg = R7;
-       jump _ex_trap_c;
+       if cc jump 1f;
 
-1:
        /*
         * We were in an interrupt handler.  By convention, all of them save
         * SYSCFG with their first instruction, so by checking whether our
@@ -202,11 +224,15 @@ ENTRY(_ex_single_step)
        cc = R7 == R6;
        if !cc jump _bfin_return_from_exception;
 
+1:
+       /* Single stepping only a single instruction, so clear the trace
+        * bit here.  */
        r7 = syscfg;
        bitclr (r7, 0);
        syscfg = R7;
 
-       /* Fall through to _bfin_return_from_exception.  */
+       jump _ex_trap_c;
+
 ENDPROC(_ex_single_step)
 
 ENTRY(_bfin_return_from_exception)