diff --git a/sys/arch/aarch64/include/mcontext.h b/sys/arch/aarch64/include/mcontext.h
index 2af2b1e5d7fc..dbead45ed432 100644
--- a/sys/arch/aarch64/include/mcontext.h
+++ b/sys/arch/aarch64/include/mcontext.h
@@ -106,6 +106,7 @@ typedef struct {
 #define	_UC_TLSBASE	0x00080000	/* see <sys/ucontext.h> */
 
 #define _UC_MACHINE_SP(uc)	((uc)->uc_mcontext.__gregs[_REG_SP])
+#define _UC_MACHINE_BP(uc)	((uc)->uc_mcontext.__gregs[_REG_X29])
 #define _UC_MACHINE_PC(uc)	((uc)->uc_mcontext.__gregs[_REG_PC])
 #define _UC_MACHINE_INTRV(uc)	((uc)->uc_mcontext.__gregs[_REG_X0])
 
diff --git a/sys/arch/alpha/include/mcontext.h b/sys/arch/alpha/include/mcontext.h
index 13ca3fd2cd7c..fd2d0ae1c051 100644
--- a/sys/arch/alpha/include/mcontext.h
+++ b/sys/arch/alpha/include/mcontext.h
@@ -96,6 +96,7 @@ typedef struct {
 #define _UC_TLSBASE	0x20	/* valid process-unique value in _REG_UNIQUE */
 
 #define _UC_MACHINE_SP(uc)	((uc)->uc_mcontext.__gregs[_REG_SP])
+#define _UC_MACHINE_BP(uc)	((uc)->uc_mcontext.__gregs[_REG_S6])
 #define _UC_MACHINE_PC(uc)	((uc)->uc_mcontext.__gregs[_REG_PC])
 #define _UC_MACHINE_INTRV(uc)	((uc)->uc_mcontext.__gregs[_REG_V0])
 
diff --git a/sys/arch/amd64/include/mcontext.h b/sys/arch/amd64/include/mcontext.h
index bed3a79e965f..42cff72bedad 100644
--- a/sys/arch/amd64/include/mcontext.h
+++ b/sys/arch/amd64/include/mcontext.h
@@ -68,6 +68,7 @@ typedef struct {
 
 /* AMD64 ABI 128-bytes "red zone". */
 #define _UC_MACHINE_SP(uc)	((uc)->uc_mcontext.__gregs[_REG_RSP] - 128)
+#define _UC_MACHINE_BP(uc)	((uc)->uc_mcontext.__gregs[_REG_RBP])
 #define _UC_MACHINE_PC(uc)	((uc)->uc_mcontext.__gregs[_REG_RIP])
 #define _UC_MACHINE_INTRV(uc)	((uc)->uc_mcontext.__gregs[_REG_RAX])
 
diff --git a/sys/arch/arm/include/mcontext.h b/sys/arch/arm/include/mcontext.h
index d0d0cc1cd3b8..9b14ee28ee15 100644
--- a/sys/arch/arm/include/mcontext.h
+++ b/sys/arch/arm/include/mcontext.h
@@ -110,6 +110,7 @@ typedef struct {
 #define _UC_MACHINE_PAD	1		/* Padding appended to ucontext_t */
 
 #define _UC_MACHINE_SP(uc)	((uc)->uc_mcontext.__gregs[_REG_SP])
+#define _UC_MACHINE_BP(uc)	((uc)->uc_mcontext.__gregs[_REG_R11])
 #define _UC_MACHINE_PC(uc)	((uc)->uc_mcontext.__gregs[_REG_PC])
 #define _UC_MACHINE_INTRV(uc)	((uc)->uc_mcontext.__gregs[_REG_R0])
 
diff --git a/sys/arch/hppa/include/mcontext.h b/sys/arch/hppa/include/mcontext.h
index a0618cebce48..c09dbf3598c5 100644
--- a/sys/arch/hppa/include/mcontext.h
+++ b/sys/arch/hppa/include/mcontext.h
@@ -50,6 +50,7 @@ typedef struct {
 } mcontext_t;
 
 #define	_UC_MACHINE_SP(uc)	((uc)->uc_mcontext.__gregs[_REG_SP])
+#define	_UC_MACHINE_BP(uc)	((uc)->uc_mcontext.__gregs[3])
 #define	_UC_MACHINE_PC(uc) 	((uc)->uc_mcontext.__gregs[_REG_PCOQH])
 #define	_UC_MACHINE_SET_PC(uc, pc)					\
 do {									\
diff --git a/sys/arch/i386/include/mcontext.h b/sys/arch/i386/include/mcontext.h
index dcaf90a60166..671b7635d355 100644
--- a/sys/arch/i386/include/mcontext.h
+++ b/sys/arch/i386/include/mcontext.h
@@ -105,6 +105,7 @@ typedef struct {
 #ifndef _UC_MACHINE_SP
 #define _UC_MACHINE_SP(uc)	((uc)->uc_mcontext.__gregs[_REG_UESP])
 #endif
+#define _UC_MACHINE_BP(uc)	((uc)->uc_mcontext.__gregs[_REG_EBP])
 #define _UC_MACHINE_PC(uc)	((uc)->uc_mcontext.__gregs[_REG_EIP])
 #define _UC_MACHINE_INTRV(uc)	((uc)->uc_mcontext.__gregs[_REG_EAX])
 
diff --git a/sys/arch/ia64/include/mcontext.h b/sys/arch/ia64/include/mcontext.h
index b9523d882e1a..2c609ecbe3f3 100644
--- a/sys/arch/ia64/include/mcontext.h
+++ b/sys/arch/ia64/include/mcontext.h
@@ -112,6 +112,7 @@ typedef struct __mcontext {
 } mcontext_t;
 
 #define _UC_MACHINE_SP(uc)	((uc)->uc_mcontext.mc_special.sp)
+#define _UC_MACHINE_BP(uc)	((uc)->uc_mcontext.__gregs[79])
 /* XXX or assembly "mov Rn = ip" or ...? */
 #define	_UC_MACHINE_PC(uc)	((uc)->uc_mcontext.mc_special.iip)
 
diff --git a/sys/arch/m68k/include/mcontext.h b/sys/arch/m68k/include/mcontext.h
index 65e3adaa7eaf..ad0c2fcd902f 100644
--- a/sys/arch/m68k/include/mcontext.h
+++ b/sys/arch/m68k/include/mcontext.h
@@ -102,6 +102,7 @@ typedef struct {
 #define	_UC_TLSBASE	0x00080000
 
 #define _UC_MACHINE_SP(uc)	((uc)->uc_mcontext.__gregs[_REG_A7])
+#define _UC_MACHINE_BP(uc)	((uc)->uc_mcontext.__gregs[_REG_A6])
 #define _UC_MACHINE_PC(uc)	((uc)->uc_mcontext.__gregs[_REG_PC])
 #define _UC_MACHINE_INTRV(uc)	((uc)->uc_mcontext.__gregs[_REG_D0])
 
diff --git a/sys/arch/mips/include/mcontext.h b/sys/arch/mips/include/mcontext.h
index 96033d7cba24..233260e08bfa 100644
--- a/sys/arch/mips/include/mcontext.h
+++ b/sys/arch/mips/include/mcontext.h
@@ -159,6 +159,7 @@ typedef struct {
 #define	_UC_TLSBASE	0x00040000
 
 #define _UC_MACHINE_SP(uc)	((uc)->uc_mcontext.__gregs[_REG_SP])
+#define _UC_MACHINE_BP(uc)	((uc)->uc_mcontext.__gregs[_REG_S8])
 #define _UC_MACHINE_PC(uc)	((uc)->uc_mcontext.__gregs[_REG_EPC])
 #define _UC_MACHINE_INTRV(uc)	((uc)->uc_mcontext.__gregs[_REG_V0])
 
diff --git a/sys/arch/or1k/include/mcontext.h b/sys/arch/or1k/include/mcontext.h
index 7cee7ee98af3..6bbd06f6d850 100644
--- a/sys/arch/or1k/include/mcontext.h
+++ b/sys/arch/or1k/include/mcontext.h
@@ -88,6 +88,7 @@ typedef struct {
 #define	_UC_TLSBASE	0x00080000	/* see <sys/ucontext.h> */
 
 #define _UC_MACHINE_SP(uc)	((uc)->uc_mcontext.__gregs[_REG_SP])
+#define _UC_MACHINE_BP(uc)	((uc)->uc_mcontext.__gregs[_REG_R2])
 #define _UC_MACHINE_PC(uc)	((uc)->uc_mcontext.__gregs[_REG_PC])
 #define _UC_MACHINE_INTRV(uc)	((uc)->uc_mcontext.__gregs[_REG_RV])
 
diff --git a/sys/arch/powerpc/include/mcontext.h b/sys/arch/powerpc/include/mcontext.h
index 5057afc06ce3..f2d990e5802f 100644
--- a/sys/arch/powerpc/include/mcontext.h
+++ b/sys/arch/powerpc/include/mcontext.h
@@ -133,6 +133,7 @@ typedef struct {
 #define	_UC_TLSBASE	0x00080000	/* thread context valid in R2 */
 
 #define _UC_MACHINE_SP(uc)	((uc)->uc_mcontext.__gregs[_REG_R1])
+#define _UC_MACHINE_BP(uc)	((uc)->uc_mcontext.__gregs[_REG_R31])
 #define _UC_MACHINE_PC(uc)	((uc)->uc_mcontext.__gregs[_REG_PC])
 #define _UC_MACHINE_INTRV(uc)	((uc)->uc_mcontext.__gregs[_REG_R3])
 
diff --git a/sys/arch/riscv/include/mcontext.h b/sys/arch/riscv/include/mcontext.h
index f72301fd47e8..6307aff00864 100644
--- a/sys/arch/riscv/include/mcontext.h
+++ b/sys/arch/riscv/include/mcontext.h
@@ -118,6 +118,7 @@ typedef struct {
 #define	_UC_TLSBASE	0x00080000	/* see <sys/ucontext.h> */
 
 #define _UC_MACHINE_SP(uc)	((uc)->uc_mcontext.__gregs[_REG_SP])
+#define _UC_MACHINE_BP(uc)	((uc)->uc_mcontext.__gregs[_REG_S0])
 #define _UC_MACHINE_PC(uc)	((uc)->uc_mcontext.__gregs[_REG_PC])
 #define _UC_MACHINE_INTRV(uc)	((uc)->uc_mcontext.__gregs[_REG_RV])
 
diff --git a/sys/arch/sh3/include/mcontext.h b/sys/arch/sh3/include/mcontext.h
index b0220b27dfbb..1324ff875110 100644
--- a/sys/arch/sh3/include/mcontext.h
+++ b/sys/arch/sh3/include/mcontext.h
@@ -82,6 +82,7 @@ typedef struct {
 } mcontext_t;
 
 #define	_UC_MACHINE_SP(uc)	((uc)->uc_mcontext.__gregs[_REG_SP])
+#define	_UC_MACHINE_BP(uc)	((uc)->uc_mcontext.__gregs[_REG_R14])
 #define	_UC_MACHINE_PC(uc)	((uc)->uc_mcontext.__gregs[_REG_PC])
 #define	_UC_MACHINE_INTRV(uc)	((uc)->uc_mcontext.__gregs[_REG_R0])
 
diff --git a/sys/arch/sparc/include/mcontext.h b/sys/arch/sparc/include/mcontext.h
index 25cb07eae0f9..571a2cf161a9 100644
--- a/sys/arch/sparc/include/mcontext.h
+++ b/sys/arch/sparc/include/mcontext.h
@@ -146,11 +146,14 @@ typedef struct {
 #ifdef __arch64__
 #define _UC_MACHINE_PAD	8		/* Padding appended to ucontext_t */
 #define	_UC_MACHINE_SP(uc)	(((uc)->uc_mcontext.__gregs[_REG_O6])+0x7ff)
+#define	_UC_MACHINE_BP(uc)	(((uc)->uc_mcontext.__gregs[_REG_O6])+0x80e)
 #define _UC_MACHINE32_PAD	43	/* compat_netbsd32 variant */
 #define	_UC_MACHINE32_SP(uc)	((uc)->uc_mcontext.__gregs[_REG_O6])
+#define	_UC_MACHINE32_BP(uc)	(((uc)->uc_mcontext.__gregs[_REG_O6])+0xf)
 #else
 #define _UC_MACHINE_PAD	43		/* Padding appended to ucontext_t */
 #define	_UC_MACHINE_SP(uc)	((uc)->uc_mcontext.__gregs[_REG_O6])
+#define	_UC_MACHINE_BP(uc)	(((uc)->uc_mcontext.__gregs[_REG_O6])+0xf)
 #endif
 #define	_UC_MACHINE_PC(uc)	((uc)->uc_mcontext.__gregs[_REG_PC])
 #define	_UC_MACHINE_INTRV(uc)	((uc)->uc_mcontext.__gregs[_REG_O0])
diff --git a/sys/arch/vax/include/mcontext.h b/sys/arch/vax/include/mcontext.h
index 5986841de7e7..87ed34e7989d 100644
--- a/sys/arch/vax/include/mcontext.h
+++ b/sys/arch/vax/include/mcontext.h
@@ -68,6 +68,7 @@ typedef struct {
 #define _UC_TLSBASE	0x00080000
 
 #define	_UC_MACHINE_SP(uc)	((uc)->uc_mcontext.__gregs[_REG_SP])
+#define	_UC_MACHINE_BP(uc)	((uc)->uc_mcontext.__gregs[_REG_FP])
 #define	_UC_MACHINE_PC(uc)	((uc)->uc_mcontext.__gregs[_REG_PC])
 #define	_UC_MACHINE_INTRV(uc)	((uc)->uc_mcontext.__gregs[_REG_R0])