Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb:
  kgdboc,tty: Fix tty polling search to use name correctly
  kgdb, x86_64: fix PS CS SS registers in gdb serial
  kgdb, x86_64: gdb serial has BX and DX reversed
  kgdb, x86, arm, mips, powerpc: ignore user space single stepping
  kgdb: could not write to the last of valid memory with kgdb

4 files changed, 35 insertions, 18 deletions

diff --git a/arch/arm/kernel/kgdb.c b/arch/arm/kernel/kgdb.c
index aaffaec..ba8ccfe 100644
--- a/arch/arm/kernel/kgdb.c
+++ b/arch/arm/kernel/kgdb.c
@@ -111,8 +111,6 @@ int kgdb_arch_handle_exception(int exception_vector, int signo,
 	case 'D':
 	case 'k':
 	case 'c':
-		kgdb_contthread = NULL;
-
 		/*
 		 * Try to read optional parameter, pc unchanged if no parm.
 		 * If this was a compiled breakpoint, we need to move
diff --git a/arch/mips/kernel/kgdb.c b/arch/mips/kernel/kgdb.c
index 8f6d58e..6e152c8 100644
--- a/arch/mips/kernel/kgdb.c
+++ b/arch/mips/kernel/kgdb.c
@@ -236,8 +236,7 @@ int kgdb_arch_handle_exception(int vector, int signo, int err_code,
 
 		atomic_set(&kgdb_cpu_doing_single_step, -1);
 		if (remcom_in_buffer[0] == 's')
-			if (kgdb_contthread)
-				atomic_set(&kgdb_cpu_doing_single_step, cpu);
+			atomic_set(&kgdb_cpu_doing_single_step, cpu);
 
 		return 0;
 	}
diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c
index b4fdf2f..fe8f71d 100644
--- a/arch/powerpc/kernel/kgdb.c
+++ b/arch/powerpc/kernel/kgdb.c
@@ -347,9 +347,8 @@ int kgdb_arch_handle_exception(int vector, int signo, int err_code,
 			linux_regs->msr |= MSR_SE;
 #endif
 			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());
 		}
 		return 0;
 	}
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index f47f0eb..8282a21 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -69,6 +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;
@@ -76,9 +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;
@@ -94,6 +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;
 }
@@ -112,6 +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;
@@ -129,8 +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;
@@ -153,6 +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];
@@ -160,9 +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];
@@ -175,6 +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
 }
 
@@ -378,10 +395,8 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
 		if (remcomInBuffer[0] == 's') {
 			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);
@@ -466,9 +481,15 @@ 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))