svn commit: r360855 - stable/12/sys/riscv/include

[John Baldwin]

Author: jhb
Date: Sat May  9 20:14:05 2020
New Revision: 360855
URL: https://svnweb.freebsd.org/changeset/base/360855

Log:
  MFC 357591:
  Read the breakpoint instruction to determine its length in BKPT_SKIP.
  
  This fixes continuing from debug.kdb.enter=1 after enabling the use of
  compressed instructions since the compiler can emit the two byte
  c.ebreak instead of the 4 byte ebreak.

Modified:
  stable/12/sys/riscv/include/db_machdep.h
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/sys/riscv/include/db_machdep.h
==============================================================================
--- stable/12/sys/riscv/include/db_machdep.h	Sat May  9 20:10:01 2020	(r360854)
+++ stable/12/sys/riscv/include/db_machdep.h	Sat May  9 20:14:05 2020	(r360855)
@@ -53,8 +53,14 @@ typedef long		db_expr_t;
 #define	BKPT_SIZE	(INSN_SIZE)
 #define	BKPT_SET(inst)	(BKPT_INST)
 
-#define	BKPT_SKIP do {				\
-	kdb_frame->tf_sepc += BKPT_SIZE;	\
+#define	BKPT_SKIP do {							\
+	uint32_t _instr;						\
+									\
+	_instr = db_get_value(PC_REGS(), sizeof(uint32_t), FALSE);	\
+	if ((_instr & 0x3) == 0x3)					\
+		kdb_frame->tf_sepc += 4;	/* ebreak */		\
+	else								\
+		kdb_frame->tf_sepc += 2;	/* c.ebreak */		\
 } while (0)
 
 #define	db_clear_single_step	kdb_cpu_clear_singlestep