Provide access to the IA32 hardware debug registers from the ddb

kernel debugger.  Proper use of these registers allows setting
hardware watchpoints for use in kernel debugging.

MFC after: 2 weeks

4 files changed, 120 insertions, 28 deletions

diff --git a/sys/amd64/amd64/db_trace.c b/sys/amd64/amd64/db_trace.c
index 64db559..a861d16 100644
--- a/sys/amd64/amd64/db_trace.c
+++ b/sys/amd64/amd64/db_trace.c
@@ -44,28 +44,45 @@
 #include <ddb/db_sym.h>
 #include <ddb/db_variables.h>
 
+db_varfcn_t db_dr0;
+db_varfcn_t db_dr1;
+db_varfcn_t db_dr2;
+db_varfcn_t db_dr3;
+db_varfcn_t db_dr4;
+db_varfcn_t db_dr5;
+db_varfcn_t db_dr6;
+db_varfcn_t db_dr7;
+
 /*
  * Machine register set.
  */
 struct db_variable db_regs[] = {
-	{ "cs",		&ddb_regs.tf_cs,  FCN_NULL },
-	{ "ds",		&ddb_regs.tf_ds,  FCN_NULL },
-	{ "es",		&ddb_regs.tf_es,  FCN_NULL },
-	{ "fs",		&ddb_regs.tf_fs,  FCN_NULL },
+	{ "cs",		&ddb_regs.tf_cs,     FCN_NULL },
+	{ "ds",		&ddb_regs.tf_ds,     FCN_NULL },
+	{ "es",		&ddb_regs.tf_es,     FCN_NULL },
+	{ "fs",		&ddb_regs.tf_fs,     FCN_NULL },
 #if 0
-	{ "gs",		&ddb_regs.tf_gs,  FCN_NULL },
+	{ "gs",		&ddb_regs.tf_gs,     FCN_NULL },
 #endif
-	{ "ss",		&ddb_regs.tf_ss,  FCN_NULL },
-	{ "eax",	&ddb_regs.tf_eax, FCN_NULL },
-	{ "ecx",	&ddb_regs.tf_ecx, FCN_NULL },
-	{ "edx",	&ddb_regs.tf_edx, FCN_NULL },
-	{ "ebx",	&ddb_regs.tf_ebx, FCN_NULL },
-	{ "esp",	&ddb_regs.tf_esp, FCN_NULL },
-	{ "ebp",	&ddb_regs.tf_ebp, FCN_NULL },
-	{ "esi",	&ddb_regs.tf_esi, FCN_NULL },
-	{ "edi",	&ddb_regs.tf_edi, FCN_NULL },
-	{ "eip",	&ddb_regs.tf_eip, FCN_NULL },
+	{ "ss",		&ddb_regs.tf_ss,     FCN_NULL },
+	{ "eax",	&ddb_regs.tf_eax,    FCN_NULL },
+	{ "ecx",	&ddb_regs.tf_ecx,    FCN_NULL },
+	{ "edx",	&ddb_regs.tf_edx,    FCN_NULL },
+	{ "ebx",	&ddb_regs.tf_ebx,    FCN_NULL },
+	{ "esp",	&ddb_regs.tf_esp,    FCN_NULL },
+	{ "ebp",	&ddb_regs.tf_ebp,    FCN_NULL },
+	{ "esi",	&ddb_regs.tf_esi,    FCN_NULL },
+	{ "edi",	&ddb_regs.tf_edi,    FCN_NULL },
+	{ "eip",	&ddb_regs.tf_eip,    FCN_NULL },
 	{ "efl",	&ddb_regs.tf_eflags, FCN_NULL },
+	{ "dr0",	NULL,		     db_dr0 },
+	{ "dr1",	NULL,		     db_dr1 },
+	{ "dr2",	NULL,		     db_dr2 },
+	{ "dr3",	NULL,		     db_dr3 },
+	{ "dr4",	NULL,		     db_dr4 },
+	{ "dr5",	NULL,		     db_dr5 },
+	{ "dr6",	NULL,		     db_dr6 },
+	{ "dr7",	NULL,		     db_dr7 },
 };
 struct db_variable *db_eregs = db_regs + sizeof(db_regs)/sizeof(db_regs[0]);
 
@@ -409,3 +426,27 @@ db_stack_trace_cmd(addr, have_addr, count, modif)
 		}
 	}
 }
+
+#define DB_DRX_FUNC(reg)                \
+int					\
+db_ ## reg (vp, valuep, op)		\
+	struct db_variable *vp;		\
+	db_expr_t * valuep;		\
+	int op;				\
+{					\
+	if (op == DB_VAR_GET)		\
+		*valuep = r ## reg ();	\
+	else				\
+		load_ ## reg (*valuep); \
+					\
+	return(0);			\
+} 
+
+DB_DRX_FUNC(dr0)
+DB_DRX_FUNC(dr1)
+DB_DRX_FUNC(dr2)
+DB_DRX_FUNC(dr3)
+DB_DRX_FUNC(dr4)
+DB_DRX_FUNC(dr5)
+DB_DRX_FUNC(dr6)
+DB_DRX_FUNC(dr7)
diff --git a/sys/amd64/amd64/support.S b/sys/amd64/amd64/support.S
index 70cc144..3218774 100644
--- a/sys/amd64/amd64/support.S
+++ b/sys/amd64/amd64/support.S
@@ -1627,12 +1627,6 @@ ENTRY(load_cr4)
 	movl	%eax,%cr4
 	ret
 
-/* void load_dr6(u_int dr6) */
-ENTRY(load_dr6)
-	movl    4(%esp),%eax
-	movl    %eax,%dr6
-	ret
-
 /* void reset_dbregs() */
 ENTRY(reset_dbregs)
 	movl    $0,%eax
diff --git a/sys/amd64/amd64/support.s b/sys/amd64/amd64/support.s
index 70cc144..3218774 100644
--- a/sys/amd64/amd64/support.s
+++ b/sys/amd64/amd64/support.s
@@ -1627,12 +1627,6 @@ ENTRY(load_cr4)
 	movl	%eax,%cr4
 	ret
 
-/* void load_dr6(u_int dr6) */
-ENTRY(load_dr6)
-	movl    4(%esp),%eax
-	movl    %eax,%dr6
-	ret
-
 /* void reset_dbregs() */
 ENTRY(reset_dbregs)
 	movl    $0,%eax
diff --git a/sys/amd64/include/cpufunc.h b/sys/amd64/include/cpufunc.h
index 40f5bb7..4a9300a 100644
--- a/sys/amd64/include/cpufunc.h
+++ b/sys/amd64/include/cpufunc.h
@@ -443,6 +443,12 @@ rdr0(void)
 	return (data);
 }
 
+static __inline void
+load_dr0(u_int sel)
+{
+	__asm __volatile("movl %0,%%dr0" : : "r" (sel));
+}
+
 static __inline u_int
 rdr1(void)
 {
@@ -451,6 +457,12 @@ rdr1(void)
 	return (data);
 }
 
+static __inline void
+load_dr1(u_int sel)
+{
+	__asm __volatile("movl %0,%%dr1" : : "r" (sel));
+}
+
 static __inline u_int
 rdr2(void)
 {
@@ -459,6 +471,12 @@ rdr2(void)
 	return (data);
 }
 
+static __inline void
+load_dr2(u_int sel)
+{
+	__asm __volatile("movl %0,%%dr2" : : "r" (sel));
+}
+
 static __inline u_int
 rdr3(void)
 {
@@ -467,6 +485,40 @@ rdr3(void)
 	return (data);
 }
 
+static __inline void
+load_dr3(u_int sel)
+{
+	__asm __volatile("movl %0,%%dr3" : : "r" (sel));
+}
+
+static __inline u_int
+rdr4(void)
+{
+	u_int	data;
+	__asm __volatile("movl %%dr4,%0" : "=r" (data));
+	return (data);
+}
+
+static __inline void
+load_dr4(u_int sel)
+{
+	__asm __volatile("movl %0,%%dr4" : : "r" (sel));
+}
+
+static __inline u_int
+rdr5(void)
+{
+	u_int	data;
+	__asm __volatile("movl %%dr5,%0" : "=r" (data));
+	return (data);
+}
+
+static __inline void
+load_dr5(u_int sel)
+{
+	__asm __volatile("movl %0,%%dr5" : : "r" (sel));
+}
+
 static __inline u_int
 rdr6(void)
 {
@@ -475,6 +527,12 @@ rdr6(void)
 	return (data);
 }
 
+static __inline void
+load_dr6(u_int sel)
+{
+	__asm __volatile("movl %0,%%dr6" : : "r" (sel));
+}
+
 static __inline u_int
 rdr7(void)
 {
@@ -483,6 +541,12 @@ rdr7(void)
 	return (data);
 }
 
+static __inline void
+load_dr7(u_int sel)
+{
+	__asm __volatile("movl %0,%%dr7" : : "r" (sel));
+}
+
 static __inline critical_t
 critical_enter(void)
 {
@@ -545,7 +609,6 @@ void	ltr		__P((u_short sel));
 u_int	rcr0		__P((void));
 u_int	rcr3		__P((void));
 u_int	rcr4		__P((void));
-void    load_dr6        __P((u_int dr6));
 void    reset_dbregs    __P((void));
 __END_DECLS