Implement breakpoints and single stepping on arm.

Obtained from:	NetBSD

4 files changed, 109 insertions, 21 deletions

diff --git a/sys/arm/arm/db_interface.c b/sys/arm/arm/db_interface.c
index d1c349a..8832097 100644
--- a/sys/arm/arm/db_interface.c
+++ b/sys/arm/arm/db_interface.c
@@ -43,6 +43,9 @@ __FBSDID("$FreeBSD$");
 #include <sys/reboot.h>
 #include <sys/systm.h>	/* just for boothowto */
 #include <sys/exec.h>
+#ifdef KDB
+#include <sys/kdb.h>
+#endif
 
 #include <vm/vm.h>
 #include <vm/pmap.h>
@@ -192,11 +195,6 @@ db_write_bytes(vm_offset_t addr, size_t size, char *data)
 	char *dst;
 	size_t loop;
 
-	/* If any part is in kernel text, use db_write_text() */
-	if (addr >= (vm_offset_t) btext && addr < (vm_offset_t) etext) {
-		return (-1);
-	}
-
 	dst = (char *)addr;
 	if (db_validate_address((u_int)dst)) {
 		db_printf("address %p is invalid\n", dst);
@@ -229,4 +227,93 @@ db_write_bytes(vm_offset_t addr, size_t size, char *data)
 }
 
 
+static u_int
+db_fetch_reg(int reg)
+{
+
+	switch (reg) {
+	case 0:
+		return (kdb_frame->tf_r0);
+	case 1:
+		return (kdb_frame->tf_r1);
+	case 2:
+		return (kdb_frame->tf_r2);
+	case 3:
+		return (kdb_frame->tf_r3);
+	case 4:
+		return (kdb_frame->tf_r4);
+	case 5:
+		return (kdb_frame->tf_r5);
+	case 6:
+		return (kdb_frame->tf_r6);
+	case 7:
+		return (kdb_frame->tf_r7);
+	case 8:
+		return (kdb_frame->tf_r8);
+	case 9:
+		return (kdb_frame->tf_r9);
+	case 10:
+		return (kdb_frame->tf_r10);
+	case 11:
+		return (kdb_frame->tf_r11);
+	case 12:
+		return (kdb_frame->tf_r12);
+	case 13:
+		return (kdb_frame->tf_svc_sp);
+	case 14:
+		return (kdb_frame->tf_svc_lr);
+	case 15:
+		return (kdb_frame->tf_pc);
+	default:
+		panic("db_fetch_reg: botch");
+	}
+}
+
+u_int
+branch_taken(u_int insn, db_addr_t pc)
+{
+	u_int addr, nregs;
+
+	switch ((insn >> 24) & 0xf) {
+	case 0xa:	/* b ... */
+	case 0xb:	/* bl ... */
+		addr = ((insn << 2) & 0x03ffffff);
+		if (addr & 0x02000000)
+			addr |= 0xfc000000;
+		return (pc + 8 + addr);
+	case 0x7:	/* ldr pc, [pc, reg, lsl #2] */
+		addr = db_fetch_reg(insn & 0xf);
+		addr = pc + 8 + (addr << 2);
+		db_read_bytes(addr, 4, (char *)&addr);
+		return (addr);
+	case 0x1:	/* mov pc, reg */
+		addr = db_fetch_reg(insn & 0xf);
+		return (addr);
+	case 0x8:	/* ldmxx reg, {..., pc} */
+	case 0x9:
+		addr = db_fetch_reg((insn >> 16) & 0xf);
+		nregs = (insn  & 0x5555) + ((insn  >> 1) & 0x5555);
+		nregs = (nregs & 0x3333) + ((nregs >> 2) & 0x3333);
+		nregs = (nregs + (nregs >> 4)) & 0x0f0f;
+		nregs = (nregs + (nregs >> 8)) & 0x001f;
+		switch ((insn >> 23) & 0x3) {
+		case 0x0:	/* ldmda */
+			addr = addr - 0;
+			break;
+		case 0x1:	/* ldmia */
+			addr = addr + 0 + ((nregs - 1) << 2);
+			break;
+		case 0x2:	/* ldmdb */
+			addr = addr - 4;
+			break;
+		case 0x3:	/* ldmib */
+			addr = addr + 4 + ((nregs - 1) << 2);
+			break;
+		}
+		db_read_bytes(addr, 4, (char *)&addr);
+		return (addr);
+	default:
+		panic("branch_taken: botch");
+	}
+}
 
diff --git a/sys/arm/arm/undefined.c b/sys/arm/arm/undefined.c
index 0c8ea41..8632867 100644
--- a/sys/arm/arm/undefined.c
+++ b/sys/arm/arm/undefined.c
@@ -45,6 +45,8 @@
  */
 
 
+#include "opt_ddb.h"
+
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
@@ -263,21 +265,13 @@ undefinedinstruction(trapframe_t *frame)
 	if ((fault_code & FAULT_USER) == 0) {
 		if (fault_instruction == KERNEL_BREAKPOINT) {
 #ifdef KDB
-		kdb_trap(0, 0, frame);
+		kdb_trap(T_BREAKPOINT, 0, frame);
 #else
 		printf("No debugger in kernel.\n");
 #endif
-		frame->tf_pc += 4;
 		return;
-		} else {
-#ifdef KDB
-			printf("Undefined instruction in kernel.\n");
-			kdb_trap(0, 0, frame);
-#else
+		} else
 			panic("Undefined instruction in kernel.\n");
-#endif
-		}
-		
 	}		
 
 #ifdef FAST_FPE
diff --git a/sys/arm/include/db_machdep.h b/sys/arm/include/db_machdep.h
index f40daa5..0682311 100644
--- a/sys/arm/include/db_machdep.h
+++ b/sys/arm/include/db_machdep.h
@@ -34,8 +34,6 @@
 #include <machine/trap.h>
 #include <machine/armreg.h>
 
-#define	BYTE_MSF	(1)
-
 #define T_BREAKPOINT	(1)
 typedef vm_offset_t	db_addr_t;
 typedef int		db_expr_t;
@@ -50,8 +48,7 @@ typedef int		db_expr_t;
 	kdb_frame->tf_pc += BKPT_SIZE; \
 } while (0)
 
-#define	db_clear_single_step(regs)
-#define	db_set_single_step(regs)
+#define SOFTWARE_SSTEP	1
 
 #define	IS_BREAKPOINT_TRAP(type, code)	(type == T_BREAKPOINT)
 #define	IS_WATCHPOINT_TRAP(type, code)	(0)
@@ -65,7 +62,8 @@ typedef int		db_expr_t;
 /* mov pc, reg
 					    0000000f  register */
 #define	inst_return(ins)	(((ins) & 0x0e108000) == 0x08108000 || \
-				 ((ins) & 0x0ff0fff0) == 0x01a0f000)
+				 ((ins) & 0x0ff0fff0) == 0x01a0f000 ||	\
+				 ((ins) & 0x0ffffff0) == 0x012fff10) /* bx */
 /* bl ...
 					    00ffffff  offset>>2 */
 #define	inst_call(ins)		(((ins) & 0x0f000000) == 0x0b000000)
@@ -74,14 +72,21 @@ typedef int		db_expr_t;
 /* ldr pc, [pc, reg, lsl #2]
 					    0000000f  register */
 
+#define	inst_branch(ins)	(((ins) & 0x0f000000) == 0x0a000000 || \
+				 ((ins) & 0x0fdffff0) == 0x079ff100)
 
 #define	inst_load(ins)		(0)
 #define	inst_store(ins)		(0)
 
+#define next_instr_address(pc, bd)	((bd) ? (pc) : ((pc) + INSN_SIZE))
+
 #define	DB_SMALL_VALUE_MAX	(0x7fffffff)
 #define	DB_SMALL_VALUE_MIN	(-0x40001)
 
-#define	DB_ELFSIZE		64
+#define	DB_ELFSIZE		32
 
 int db_validate_address(vm_offset_t);
+
+u_int branch_taken (u_int insn, u_int pc);
+
 #endif /* !_MACHINE_DB_MACHDEP_H_ */
diff --git a/sys/arm/include/kdb.h b/sys/arm/include/kdb.h
index ba8b3b9..0adf7e1 100644
--- a/sys/arm/include/kdb.h
+++ b/sys/arm/include/kdb.h
@@ -31,6 +31,7 @@
 
 #include <machine/frame.h>
 #include <machine/psl.h>
+#include <machine/cpufunc.h>
 
 static __inline void
 kdb_cpu_clear_singlestep(void)
@@ -45,6 +46,7 @@ kdb_cpu_set_singlestep(void)
 static __inline void
 kdb_cpu_trap(int type, int code)
 {
+	cpu_idcache_wbinv_all();
 }
 
 #endif /* _MACHINE_KDB_H_ */