From 1328e1c4beb0c88b4291ca7849ce66cc2078ee8d Mon Sep 17 00:00:00 2001
From: Daniel Eischen <deischen@FreeBSD.org>
Date: Fri, 25 Apr 2003 01:50:30 +0000
Subject: [PATCH] Add an argument to get_mcontext() which specified whether the
 syscall return values should be cleared.  The system calls getcontext() and
 swapcontext() want to return 0 on success but these contexts can be switched
 to at a later time so the return values need to be cleared in the saved
 register sets.  Other callers of get_mcontext() would normally want the
 context without clearing the return values.

Remove the i386-specific context saving from the KSE code.
get_mcontext() is not i386-specific any more.

Fix a bad pointer in the alpha get_mcontext() code.  The
context was being bcopy()'d from &td->tf_frame, but tf_frame
is itself a pointer, so the thread was being copied instead.
Spotted by jake.

Glanced at by:  jake
Reviewed by:    bde (months ago)
---
 sys/alpha/alpha/machdep.c     | 10 +++++++---
 sys/amd64/amd64/machdep.c     | 11 ++++++++---
 sys/i386/i386/machdep.c       | 11 ++++++++---
 sys/ia64/ia64/machdep.c       |  2 +-
 sys/kern/kern_context.c       |  4 ++--
 sys/kern/kern_kse.c           | 16 +---------------
 sys/kern/kern_thread.c        | 16 +---------------
 sys/pc98/i386/machdep.c       | 11 ++++++++---
 sys/pc98/pc98/machdep.c       | 11 ++++++++---
 sys/powerpc/aim/machdep.c     |  2 +-
 sys/powerpc/powerpc/machdep.c |  2 +-
 sys/sparc64/sparc64/machdep.c |  6 +++++-
 sys/sys/ucontext.h            |  2 +-
 13 files changed, 52 insertions(+), 52 deletions(-)

diff --git a/sys/alpha/alpha/machdep.c b/sys/alpha/alpha/machdep.c
index c7e8c8c6112..1efc6b9eedb 100644
--- a/sys/alpha/alpha/machdep.c
+++ b/sys/alpha/alpha/machdep.c
@@ -1977,13 +1977,17 @@ set_regs(td, regs)
 }
 
 int
-get_mcontext(struct thread *td, mcontext_t *mcp)
+get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
 {
 	/*
 	 * Use a trapframe for getsetcontext, so just copy the
 	 * threads trapframe.
 	 */
-	bcopy(&td->td_frame, &mcp->mc_regs, sizeof(td->td_frame));
+	bcopy(td->td_frame, &mcp->mc_regs, sizeof(struct trapframe));
+	if (clear_ret != 0) {
+		mcp->mc_regs[FRAME_V0] = 0;
+		mcp->mc_regs[FRAME_A4] = 0;
+	}
 
 	/*
 	 * When the thread is the current thread, the user stack pointer
@@ -2029,7 +2033,7 @@ set_mcontext(struct thread *td, const mcontext_t *mcp)
 		 * The context is a trapframe, so just copy it over the
 		 * threads frame.
 		 */
-		bcopy(&mcp->mc_regs, &td->td_frame, sizeof(td->td_frame));
+		bcopy(&mcp->mc_regs, td->td_frame, sizeof(struct trapframe));
 	}
 	return (0);
 }
diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index d2dba4ff1ed..e5377d4477e 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -2359,7 +2359,7 @@ set_fpregs(struct thread *td, struct fpreg *fpregs)
  * Get machine context.
  */
 int
-get_mcontext(struct thread *td, mcontext_t *mcp)
+get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
 {
 	struct trapframe *tp;
 
@@ -2376,10 +2376,15 @@ get_mcontext(struct thread *td, mcontext_t *mcp)
 	mcp->mc_esi = tp->tf_esi;
 	mcp->mc_ebp = tp->tf_ebp;
 	mcp->mc_isp = tp->tf_isp;
+	if (clear_ret != 0) {
+		mcp->mc_eax = 0;
+		mcp->mc_edx = 0;
+	} else {
+		mcp->mc_eax = tp->tf_eax;
+		mcp->mc_edx = tp->tf_edx;
+	}
 	mcp->mc_ebx = tp->tf_ebx;
-	mcp->mc_edx = tp->tf_edx;
 	mcp->mc_ecx = tp->tf_ecx;
-	mcp->mc_eax = tp->tf_eax;
 	mcp->mc_eip = tp->tf_eip;
 	mcp->mc_cs = tp->tf_cs;
 	mcp->mc_eflags = tp->tf_eflags;
diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index d2dba4ff1ed..e5377d4477e 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -2359,7 +2359,7 @@ set_fpregs(struct thread *td, struct fpreg *fpregs)
  * Get machine context.
  */
 int
-get_mcontext(struct thread *td, mcontext_t *mcp)
+get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
 {
 	struct trapframe *tp;
 
@@ -2376,10 +2376,15 @@ get_mcontext(struct thread *td, mcontext_t *mcp)
 	mcp->mc_esi = tp->tf_esi;
 	mcp->mc_ebp = tp->tf_ebp;
 	mcp->mc_isp = tp->tf_isp;
+	if (clear_ret != 0) {
+		mcp->mc_eax = 0;
+		mcp->mc_edx = 0;
+	} else {
+		mcp->mc_eax = tp->tf_eax;
+		mcp->mc_edx = tp->tf_edx;
+	}
 	mcp->mc_ebx = tp->tf_ebx;
-	mcp->mc_edx = tp->tf_edx;
 	mcp->mc_ecx = tp->tf_ecx;
-	mcp->mc_eax = tp->tf_eax;
 	mcp->mc_eip = tp->tf_eip;
 	mcp->mc_cs = tp->tf_cs;
 	mcp->mc_eflags = tp->tf_eflags;
diff --git a/sys/ia64/ia64/machdep.c b/sys/ia64/ia64/machdep.c
index fb16a72d8e0..cff38fed3b6 100644
--- a/sys/ia64/ia64/machdep.c
+++ b/sys/ia64/ia64/machdep.c
@@ -1018,7 +1018,7 @@ freebsd4_sigreturn(struct thread *td, struct freebsd4_sigreturn_args *uap)
 #endif
 
 int
-get_mcontext(struct thread *td, mcontext_t *mcp)
+get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
 {
 
 	return (ENOSYS);
diff --git a/sys/kern/kern_context.c b/sys/kern/kern_context.c
index 653475d2df2..ed30a8b3e18 100644
--- a/sys/kern/kern_context.c
+++ b/sys/kern/kern_context.c
@@ -71,7 +71,7 @@ getcontext(struct thread *td, struct getcontext_args *uap)
 	if (uap->ucp == NULL)
 		ret = EINVAL;
 	else {
-		get_mcontext(td, &uc.uc_mcontext);
+		get_mcontext(td, &uc.uc_mcontext, 1);
 		PROC_LOCK(td->td_proc);
 		uc.uc_sigmask = td->td_sigmask;
 		PROC_UNLOCK(td->td_proc);
@@ -115,7 +115,7 @@ swapcontext(struct thread *td, struct swapcontext_args *uap)
 	if (uap->oucp == NULL || uap->ucp == NULL)
 		ret = EINVAL;
 	else {
-		get_mcontext(td, &uc.uc_mcontext);
+		get_mcontext(td, &uc.uc_mcontext, 1);
 		PROC_LOCK(td->td_proc);
 		uc.uc_sigmask = td->td_sigmask;
 		PROC_UNLOCK(td->td_proc);
diff --git a/sys/kern/kern_kse.c b/sys/kern/kern_kse.c
index 48f5ac0fa12..ac7daa455bd 100644
--- a/sys/kern/kern_kse.c
+++ b/sys/kern/kern_kse.c
@@ -729,13 +729,7 @@ void
 thread_getcontext(struct thread *td, ucontext_t *uc)
 {
 
-/*
- * XXX this is declared in a MD include file, i386/include/ucontext.h but
- * is used in MI code.
- */
-#ifdef __i386__
-	get_mcontext(td, &uc->uc_mcontext);
-#endif
+	get_mcontext(td, &uc->uc_mcontext, 0);
 	PROC_LOCK(td->td_proc);
 	uc->uc_sigmask = td->td_sigmask;
 	PROC_UNLOCK(td->td_proc);
@@ -751,15 +745,7 @@ thread_setcontext(struct thread *td, ucontext_t *uc)
 {
 	int ret;
 
-/*
- * XXX this is declared in a MD include file, i386/include/ucontext.h but
- * is used in MI code.
- */
-#ifdef __i386__
 	ret = set_mcontext(td, &uc->uc_mcontext);
-#else
-	ret = ENOSYS;
-#endif
 	if (ret == 0) {
 		SIG_CANTMASK(uc->uc_sigmask);
 		PROC_LOCK(td->td_proc);
diff --git a/sys/kern/kern_thread.c b/sys/kern/kern_thread.c
index 48f5ac0fa12..ac7daa455bd 100644
--- a/sys/kern/kern_thread.c
+++ b/sys/kern/kern_thread.c
@@ -729,13 +729,7 @@ void
 thread_getcontext(struct thread *td, ucontext_t *uc)
 {
 
-/*
- * XXX this is declared in a MD include file, i386/include/ucontext.h but
- * is used in MI code.
- */
-#ifdef __i386__
-	get_mcontext(td, &uc->uc_mcontext);
-#endif
+	get_mcontext(td, &uc->uc_mcontext, 0);
 	PROC_LOCK(td->td_proc);
 	uc->uc_sigmask = td->td_sigmask;
 	PROC_UNLOCK(td->td_proc);
@@ -751,15 +745,7 @@ thread_setcontext(struct thread *td, ucontext_t *uc)
 {
 	int ret;
 
-/*
- * XXX this is declared in a MD include file, i386/include/ucontext.h but
- * is used in MI code.
- */
-#ifdef __i386__
 	ret = set_mcontext(td, &uc->uc_mcontext);
-#else
-	ret = ENOSYS;
-#endif
 	if (ret == 0) {
 		SIG_CANTMASK(uc->uc_sigmask);
 		PROC_LOCK(td->td_proc);
diff --git a/sys/pc98/i386/machdep.c b/sys/pc98/i386/machdep.c
index 707b8fc7d3a..b9013a22da3 100644
--- a/sys/pc98/i386/machdep.c
+++ b/sys/pc98/i386/machdep.c
@@ -2428,7 +2428,7 @@ set_fpregs(struct thread *td, struct fpreg *fpregs)
  * Get machine context.
  */
 int
-get_mcontext(struct thread *td, mcontext_t *mcp)
+get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
 {
 	struct trapframe *tp;
 
@@ -2446,9 +2446,14 @@ get_mcontext(struct thread *td, mcontext_t *mcp)
 	mcp->mc_ebp = tp->tf_ebp;
 	mcp->mc_isp = tp->tf_isp;
 	mcp->mc_ebx = tp->tf_ebx;
-	mcp->mc_edx = tp->tf_edx;
+	if (clear_ret != 0) {
+		mcp->mc_eax = 0;
+		mcp->mc_edx = 0;
+	} else {
+		mcp->mc_eax = tp->tf_eax;
+		mcp->mc_edx = tp->tf_edx;
+	}
 	mcp->mc_ecx = tp->tf_ecx;
-	mcp->mc_eax = tp->tf_eax;
 	mcp->mc_eip = tp->tf_eip;
 	mcp->mc_cs = tp->tf_cs;
 	mcp->mc_eflags = tp->tf_eflags;
diff --git a/sys/pc98/pc98/machdep.c b/sys/pc98/pc98/machdep.c
index 707b8fc7d3a..b9013a22da3 100644
--- a/sys/pc98/pc98/machdep.c
+++ b/sys/pc98/pc98/machdep.c
@@ -2428,7 +2428,7 @@ set_fpregs(struct thread *td, struct fpreg *fpregs)
  * Get machine context.
  */
 int
-get_mcontext(struct thread *td, mcontext_t *mcp)
+get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
 {
 	struct trapframe *tp;
 
@@ -2446,9 +2446,14 @@ get_mcontext(struct thread *td, mcontext_t *mcp)
 	mcp->mc_ebp = tp->tf_ebp;
 	mcp->mc_isp = tp->tf_isp;
 	mcp->mc_ebx = tp->tf_ebx;
-	mcp->mc_edx = tp->tf_edx;
+	if (clear_ret != 0) {
+		mcp->mc_eax = 0;
+		mcp->mc_edx = 0;
+	} else {
+		mcp->mc_eax = tp->tf_eax;
+		mcp->mc_edx = tp->tf_edx;
+	}
 	mcp->mc_ecx = tp->tf_ecx;
-	mcp->mc_eax = tp->tf_eax;
 	mcp->mc_eip = tp->tf_eip;
 	mcp->mc_cs = tp->tf_cs;
 	mcp->mc_eflags = tp->tf_eflags;
diff --git a/sys/powerpc/aim/machdep.c b/sys/powerpc/aim/machdep.c
index 39fcc4945cc..81fb604a8b2 100644
--- a/sys/powerpc/aim/machdep.c
+++ b/sys/powerpc/aim/machdep.c
@@ -562,7 +562,7 @@ freebsd4_sigreturn(struct thread *td, struct freebsd4_sigreturn_args *uap)
 #endif
 
 int
-get_mcontext(struct thread *td, mcontext_t *mcp)
+get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
 {
 
 	return (ENOSYS);
diff --git a/sys/powerpc/powerpc/machdep.c b/sys/powerpc/powerpc/machdep.c
index 39fcc4945cc..81fb604a8b2 100644
--- a/sys/powerpc/powerpc/machdep.c
+++ b/sys/powerpc/powerpc/machdep.c
@@ -562,7 +562,7 @@ freebsd4_sigreturn(struct thread *td, struct freebsd4_sigreturn_args *uap)
 #endif
 
 int
-get_mcontext(struct thread *td, mcontext_t *mcp)
+get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
 {
 
 	return (ENOSYS);
diff --git a/sys/sparc64/sparc64/machdep.c b/sys/sparc64/sparc64/machdep.c
index 47d909394ce..6cf0f6af2df 100644
--- a/sys/sparc64/sparc64/machdep.c
+++ b/sys/sparc64/sparc64/machdep.c
@@ -535,7 +535,7 @@ freebsd4_sigreturn(struct thread *td, struct freebsd4_sigreturn_args *uap)
 #endif
 
 int
-get_mcontext(struct thread *td, mcontext_t *mc)
+get_mcontext(struct thread *td, mcontext_t *mc, int clear_ret)
 {
 	struct trapframe *tf;
 	struct pcb *pcb;
@@ -543,6 +543,10 @@ get_mcontext(struct thread *td, mcontext_t *mc)
 	tf = td->td_frame;
 	pcb = td->td_pcb;
 	bcopy(tf, mc, sizeof(*tf));
+	if (clear_ret != 0) {
+		mc->mc_out[0] = 0;
+		mc->mc_out[1] = 0;
+	}
 	mc->mc_flags = _MC_VERSION;
 	critical_enter();
 	if ((tf->tf_fprs & FPRS_FEF) != 0) {
diff --git a/sys/sys/ucontext.h b/sys/sys/ucontext.h
index 1ea01d577ac..70402ffc394 100644
--- a/sys/sys/ucontext.h
+++ b/sys/sys/ucontext.h
@@ -84,7 +84,7 @@ __END_DECLS
 struct thread;
 
 /* Machine-dependent functions: */
-int	get_mcontext(struct thread *td, mcontext_t *mcp);
+int	get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret);
 int	set_mcontext(struct thread *td, const mcontext_t *mcp);
 
 #endif /* !_KERNEL */