Change the clear_ret argument of get_mcontext() to be a flags argument.

Since all callers either passed 0 or 1 for clear_ret, define bit 0 in
the flags for use as clear_ret. Reserve bits 1, 2 and 3 for use by MI
code for possible (but unlikely) future use. The remaining bits are for
use by MD code.

This change is triggered by a need on ia64 to have another knob for
get_mcontext().

11 files changed, 27 insertions, 20 deletions

diff --git a/sys/alpha/alpha/machdep.c b/sys/alpha/alpha/machdep.c
index 5de6070..91f90e4 100644
--- a/sys/alpha/alpha/machdep.c
+++ b/sys/alpha/alpha/machdep.c
@@ -2027,14 +2027,14 @@ set_regs(td, regs)
 }
 
 int
-get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
+get_mcontext(struct thread *td, mcontext_t *mcp, int flags)
 {
 	/*
 	 * Use a trapframe for getsetcontext, so just copy the
 	 * threads trapframe.
 	 */
 	bcopy(td->td_frame, &mcp->mc_regs, sizeof(struct trapframe));
-	if (clear_ret != 0) {
+	if (flags & GET_MC_CLEAR_RET) {
 		mcp->mc_regs[FRAME_V0] = 0;
 		mcp->mc_regs[FRAME_A4] = 0;
 		mcp->mc_regs[FRAME_A3] = 0;
diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index 8272f72..5e6254d 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -1441,7 +1441,7 @@ set_fpregs(struct thread *td, struct fpreg *fpregs)
  * Get machine context.
  */
 int
-get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
+get_mcontext(struct thread *td, mcontext_t *mcp, int flags)
 {
 	struct trapframe *tp;
 
@@ -1462,7 +1462,7 @@ get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
 	mcp->mc_rbp = tp->tf_rbp;
 	mcp->mc_rbx = tp->tf_rbx;
 	mcp->mc_rcx = tp->tf_rcx;
-	if (clear_ret != 0) {
+	if (flags & GET_MC_CLEAR_RET) {
 		mcp->mc_rax = 0;
 		mcp->mc_rdx = 0;
 	} else {
diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index f1ef3e7..1edd08f 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -2377,7 +2377,7 @@ set_fpregs(struct thread *td, struct fpreg *fpregs)
  * Get machine context.
  */
 int
-get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
+get_mcontext(struct thread *td, mcontext_t *mcp, int flags)
 {
 	struct trapframe *tp;
 
@@ -2394,7 +2394,7 @@ get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
 	mcp->mc_esi = tp->tf_esi;
 	mcp->mc_ebp = tp->tf_ebp;
 	mcp->mc_isp = tp->tf_isp;
-	if (clear_ret != 0) {
+	if (flags & GET_MC_CLEAR_RET) {
 		mcp->mc_eax = 0;
 		mcp->mc_edx = 0;
 	} else {
diff --git a/sys/ia64/ia64/machdep.c b/sys/ia64/ia64/machdep.c
index fb4d5bf..25630c8 100644
--- a/sys/ia64/ia64/machdep.c
+++ b/sys/ia64/ia64/machdep.c
@@ -1073,7 +1073,7 @@ freebsd4_sigreturn(struct thread *td, struct freebsd4_sigreturn_args *uap)
 #endif
 
 int
-get_mcontext(struct thread *td, mcontext_t *mc, int clear_ret)
+get_mcontext(struct thread *td, mcontext_t *mc, int flags)
 {
 	struct _special s;
 	struct trapframe *tf;
@@ -1108,7 +1108,7 @@ get_mcontext(struct thread *td, mcontext_t *mc, int clear_ret)
 		 * return register, just like gr8-gr10.
 		 */
 		mc->mc_flags |= _MC_FLAGS_RETURN_VALID;
-		if (!clear_ret) {
+		if ((flags & GET_MC_CLEAR_RET) == 0) {
 			mc->mc_scratch.gr8 = tf->tf_scratch.gr8;
 			mc->mc_scratch.gr9 = tf->tf_scratch.gr9;
 			mc->mc_scratch.gr10 = tf->tf_scratch.gr10;
diff --git a/sys/kern/kern_context.c b/sys/kern/kern_context.c
index ca3e2b1..300b1f4 100644
--- a/sys/kern/kern_context.c
+++ b/sys/kern/kern_context.c
@@ -70,7 +70,7 @@ getcontext(struct thread *td, struct getcontext_args *uap)
 	if (uap->ucp == NULL)
 		ret = EINVAL;
 	else {
-		get_mcontext(td, &uc.uc_mcontext, 1);
+		get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET);
 		PROC_LOCK(td->td_proc);
 		uc.uc_sigmask = td->td_sigmask;
 		PROC_UNLOCK(td->td_proc);
@@ -114,7 +114,7 @@ swapcontext(struct thread *td, struct swapcontext_args *uap)
 	if (uap->oucp == NULL || uap->ucp == NULL)
 		ret = EINVAL;
 	else {
-		get_mcontext(td, &uc.uc_mcontext, 1);
+		get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET);
 		PROC_LOCK(td->td_proc);
 		uc.uc_sigmask = td->td_sigmask;
 		PROC_UNLOCK(td->td_proc);
diff --git a/sys/pc98/i386/machdep.c b/sys/pc98/i386/machdep.c
index 4987d41..d49ada9 100644
--- a/sys/pc98/i386/machdep.c
+++ b/sys/pc98/i386/machdep.c
@@ -2435,7 +2435,7 @@ set_fpregs(struct thread *td, struct fpreg *fpregs)
  * Get machine context.
  */
 int
-get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
+get_mcontext(struct thread *td, mcontext_t *mcp, int flags)
 {
 	struct trapframe *tp;
 
@@ -2453,7 +2453,7 @@ get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
 	mcp->mc_ebp = tp->tf_ebp;
 	mcp->mc_isp = tp->tf_isp;
 	mcp->mc_ebx = tp->tf_ebx;
-	if (clear_ret != 0) {
+	if (flags & GET_MC_CLEAR_RET) {
 		mcp->mc_eax = 0;
 		mcp->mc_edx = 0;
 	} else {
diff --git a/sys/pc98/pc98/machdep.c b/sys/pc98/pc98/machdep.c
index 4987d41..d49ada9 100644
--- a/sys/pc98/pc98/machdep.c
+++ b/sys/pc98/pc98/machdep.c
@@ -2435,7 +2435,7 @@ set_fpregs(struct thread *td, struct fpreg *fpregs)
  * Get machine context.
  */
 int
-get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
+get_mcontext(struct thread *td, mcontext_t *mcp, int flags)
 {
 	struct trapframe *tp;
 
@@ -2453,7 +2453,7 @@ get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
 	mcp->mc_ebp = tp->tf_ebp;
 	mcp->mc_isp = tp->tf_isp;
 	mcp->mc_ebx = tp->tf_ebx;
-	if (clear_ret != 0) {
+	if (flags & GET_MC_CLEAR_RET) {
 		mcp->mc_eax = 0;
 		mcp->mc_edx = 0;
 	} else {
diff --git a/sys/powerpc/aim/machdep.c b/sys/powerpc/aim/machdep.c
index 325da09..5dbb5ee 100644
--- a/sys/powerpc/aim/machdep.c
+++ b/sys/powerpc/aim/machdep.c
@@ -581,7 +581,7 @@ freebsd4_sigreturn(struct thread *td, struct freebsd4_sigreturn_args *uap)
 #endif
 
 int
-get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
+get_mcontext(struct thread *td, mcontext_t *mcp, int flags)
 {
 
 	return (ENOSYS);
diff --git a/sys/powerpc/powerpc/machdep.c b/sys/powerpc/powerpc/machdep.c
index 325da09..5dbb5ee 100644
--- a/sys/powerpc/powerpc/machdep.c
+++ b/sys/powerpc/powerpc/machdep.c
@@ -581,7 +581,7 @@ freebsd4_sigreturn(struct thread *td, struct freebsd4_sigreturn_args *uap)
 #endif
 
 int
-get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
+get_mcontext(struct thread *td, mcontext_t *mcp, int flags)
 {
 
 	return (ENOSYS);
diff --git a/sys/sparc64/sparc64/machdep.c b/sys/sparc64/sparc64/machdep.c
index 3621fef..a099638 100644
--- a/sys/sparc64/sparc64/machdep.c
+++ b/sys/sparc64/sparc64/machdep.c
@@ -564,7 +564,7 @@ freebsd4_sigreturn(struct thread *td, struct freebsd4_sigreturn_args *uap)
 #endif
 
 int
-get_mcontext(struct thread *td, mcontext_t *mc, int clear_ret)
+get_mcontext(struct thread *td, mcontext_t *mc, int flags)
 {
 	struct trapframe *tf;
 	struct pcb *pcb;
@@ -572,7 +572,7 @@ get_mcontext(struct thread *td, mcontext_t *mc, int clear_ret)
 	tf = td->td_frame;
 	pcb = td->td_pcb;
 	bcopy(tf, mc, sizeof(*tf));
-	if (clear_ret != 0) {
+	if (flags & GET_MC_CLEAR_RET) {
 		mc->mc_out[0] = 0;
 		mc->mc_out[1] = 0;
 	}
diff --git a/sys/sys/ucontext.h b/sys/sys/ucontext.h
index 70402ff..85a5fd6 100644
--- a/sys/sys/ucontext.h
+++ b/sys/sys/ucontext.h
@@ -83,9 +83,16 @@ __END_DECLS
 
 struct thread;
 
+/*
+ * Flags for get_mcontext().  The low order 4 bits (i.e a mask of 0x0f) are
+ * reserved for use by machine independent code.  All other bits are for use
+ * by machine dependent code.
+ */
+#define	GET_MC_CLEAR_RET	1
+
 /* Machine-dependent functions: */
-int	get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret);
-int	set_mcontext(struct thread *td, const mcontext_t *mcp);
+int	get_mcontext(struct thread *, mcontext_t *, int);
+int	set_mcontext(struct thread *, const mcontext_t *);
 
 #endif /* !_KERNEL */