kgdb, x86: Avoid invoking kgdb_nmicallback twice per NMI

[linux-2.6-omap-h63xx.git] / arch / x86 / kernel / kgdb.c

diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index 7d651adcb22273467fd54a07cc47d91bd2ca1c40..10435a120d2227bffd79a3df193f4238049ce2b0 100644 (file)
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -46,11 +46,7 @@
 #include <asm/apicdef.h>
 #include <asm/system.h>
 
-#ifdef CONFIG_X86_32
-# include <mach_ipi.h>
-#else
-# include <asm/mach_apic.h>
-#endif
+#include <mach_ipi.h>
 
 /*
  * Put the error code here just in case the user cares:
@@ -73,6 +69,9 @@ static int gdb_x86vector = -1;
  */
 void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
 {
+#ifndef CONFIG_X86_32
+       u32 *gdb_regs32 = (u32 *)gdb_regs;
+#endif
        gdb_regs[GDB_AX]        = regs->ax;
        gdb_regs[GDB_BX]        = regs->bx;
        gdb_regs[GDB_CX]        = regs->cx;
@@ -80,9 +79,9 @@ void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
        gdb_regs[GDB_SI]        = regs->si;
        gdb_regs[GDB_DI]        = regs->di;
        gdb_regs[GDB_BP]        = regs->bp;
-       gdb_regs[GDB_PS]        = regs->flags;
        gdb_regs[GDB_PC]        = regs->ip;
 #ifdef CONFIG_X86_32
+       gdb_regs[GDB_PS]        = regs->flags;
        gdb_regs[GDB_DS]        = regs->ds;
        gdb_regs[GDB_ES]        = regs->es;
        gdb_regs[GDB_CS]        = regs->cs;
@@ -98,6 +97,9 @@ void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
        gdb_regs[GDB_R13]       = regs->r13;
        gdb_regs[GDB_R14]       = regs->r14;
        gdb_regs[GDB_R15]       = regs->r15;
+       gdb_regs32[GDB_PS]      = regs->flags;
+       gdb_regs32[GDB_CS]      = regs->cs;
+       gdb_regs32[GDB_SS]      = regs->ss;
 #endif
        gdb_regs[GDB_SP]        = regs->sp;
 }
@@ -116,6 +118,9 @@ void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
  */
 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
 {
+#ifndef CONFIG_X86_32
+       u32 *gdb_regs32 = (u32 *)gdb_regs;
+#endif
        gdb_regs[GDB_AX]        = 0;
        gdb_regs[GDB_BX]        = 0;
        gdb_regs[GDB_CX]        = 0;
@@ -133,8 +138,10 @@ void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
        gdb_regs[GDB_FS]        = 0xFFFF;
        gdb_regs[GDB_GS]        = 0xFFFF;
 #else
-       gdb_regs[GDB_PS]        = *(unsigned long *)(p->thread.sp + 8);
-       gdb_regs[GDB_PC]        = 0;
+       gdb_regs32[GDB_PS]      = *(unsigned long *)(p->thread.sp + 8);
+       gdb_regs32[GDB_CS]      = __KERNEL_CS;
+       gdb_regs32[GDB_SS]      = __KERNEL_DS;
+       gdb_regs[GDB_PC]        = p->thread.ip;
        gdb_regs[GDB_R8]        = 0;
        gdb_regs[GDB_R9]        = 0;
        gdb_regs[GDB_R10]       = 0;
@@ -157,6 +164,9 @@ void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
  */
 void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
 {
+#ifndef CONFIG_X86_32
+       u32 *gdb_regs32 = (u32 *)gdb_regs;
+#endif
        regs->ax                = gdb_regs[GDB_AX];
        regs->bx                = gdb_regs[GDB_BX];
        regs->cx                = gdb_regs[GDB_CX];
@@ -164,9 +174,9 @@ void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
        regs->si                = gdb_regs[GDB_SI];
        regs->di                = gdb_regs[GDB_DI];
        regs->bp                = gdb_regs[GDB_BP];
-       regs->flags             = gdb_regs[GDB_PS];
        regs->ip                = gdb_regs[GDB_PC];
 #ifdef CONFIG_X86_32
+       regs->flags             = gdb_regs[GDB_PS];
        regs->ds                = gdb_regs[GDB_DS];
        regs->es                = gdb_regs[GDB_ES];
        regs->cs                = gdb_regs[GDB_CS];
@@ -179,6 +189,9 @@ void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
        regs->r13               = gdb_regs[GDB_R13];
        regs->r14               = gdb_regs[GDB_R14];
        regs->r15               = gdb_regs[GDB_R15];
+       regs->flags             = gdb_regs32[GDB_PS];
+       regs->cs                = gdb_regs32[GDB_CS];
+       regs->ss                = gdb_regs32[GDB_SS];
 #endif
 }
 
@@ -370,20 +383,20 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
                ptr = &remcomInBuffer[1];
                if (kgdb_hex2long(&ptr, &addr))
                        linux_regs->ip = addr;
+       case 'D':
+       case 'k':
                newPC = linux_regs->ip;
 
                /* clear the trace bit */
-               linux_regs->flags &= ~TF_MASK;
+               linux_regs->flags &= ~X86_EFLAGS_TF;
                atomic_set(&kgdb_cpu_doing_single_step, -1);
 
                /* set the trace bit if we're stepping */
                if (remcomInBuffer[0] == 's') {
-                       linux_regs->flags |= TF_MASK;
+                       linux_regs->flags |= X86_EFLAGS_TF;
                        kgdb_single_step = 1;
-                       if (kgdb_contthread) {
-                               atomic_set(&kgdb_cpu_doing_single_step,
-                                          raw_smp_processor_id());
-                       }
+                       atomic_set(&kgdb_cpu_doing_single_step,
+                                  raw_smp_processor_id());
                }
 
                get_debugreg(dr6, 6);
@@ -442,12 +455,7 @@ static int __kgdb_notify(struct die_args *args, unsigned long cmd)
                return NOTIFY_DONE;
 
        case DIE_NMI_IPI:
-               if (atomic_read(&kgdb_active) != -1) {
-                       /* KGDB CPU roundup */
-                       kgdb_nmicallback(raw_smp_processor_id(), regs);
-                       was_in_debug_nmi[raw_smp_processor_id()] = 1;
-                       touch_nmi_watchdog();
-               }
+               /* Just ignore, we will handle the roundup on DIE_NMI. */
                return NOTIFY_DONE;
 
        case DIE_NMIUNKNOWN:
@@ -468,9 +476,15 @@ static int __kgdb_notify(struct die_args *args, unsigned long cmd)
 
        case DIE_DEBUG:
                if (atomic_read(&kgdb_cpu_doing_single_step) ==
-                       raw_smp_processor_id() &&
-                       user_mode(regs))
-                       return single_step_cont(regs, args);
+                   raw_smp_processor_id()) {
+                       if (user_mode(regs))
+                               return single_step_cont(regs, args);
+                       break;
+               } else if (test_thread_flag(TIF_SINGLESTEP))
+                       /* This means a user thread is single stepping
+                        * a system call which should be ignored
+                        */
+                       return NOTIFY_DONE;
                /* fall through */
        default:
                if (user_mode(regs))
@@ -480,6 +494,8 @@ static int __kgdb_notify(struct die_args *args, unsigned long cmd)
        if (kgdb_handle_exception(args->trapnr, args->signr, args->err, regs))
                return NOTIFY_DONE;
 
+       /* Must touch watchdog before return to normal operation */
+       touch_nmi_watchdog();
        return NOTIFY_STOP;
 }