svn commit: r229023 - in stable/9/sys: amd64/amd64 amd64/include i386/i386 i386/include

[Konstantin Belousov]

Author: kib
Date: Fri Dec 30 20:35:13 2011
New Revision: 229023
URL: http://svn.freebsd.org/changeset/base/229023

Log:
  MFC r227399:
  Attempt to improve formatting and content of several comments for
  amd64 and i386 MD code.

Modified:
  stable/9/sys/amd64/amd64/trap.c
  stable/9/sys/amd64/include/signal.h
  stable/9/sys/amd64/include/ucontext.h
  stable/9/sys/i386/i386/trap.c
  stable/9/sys/i386/include/signal.h
  stable/9/sys/i386/include/ucontext.h
Directory Properties:
  stable/9/sys/   (props changed)

Modified: stable/9/sys/amd64/amd64/trap.c
==============================================================================
--- stable/9/sys/amd64/amd64/trap.c	Fri Dec 30 20:24:52 2011	(r229022)
+++ stable/9/sys/amd64/amd64/trap.c	Fri Dec 30 20:35:13 2011	(r229023)
@@ -900,9 +900,9 @@ cpu_fetch_syscall_args(struct thread *td
 #include "../../kern/subr_syscall.c"
 
 /*
- *	syscall -	system call request C handler
- *
- *	A system call is essentially treated as a trap.
+ * System call handler for native binaries.  The trap frame is already
+ * set up by the assembler trampoline and a pointer to it is saved in
+ * td_frame.
  */
 void
 amd64_syscall(struct thread *td, int traced)

Modified: stable/9/sys/amd64/include/signal.h
==============================================================================
--- stable/9/sys/amd64/include/signal.h	Fri Dec 30 20:24:52 2011	(r229022)
+++ stable/9/sys/amd64/include/signal.h	Fri Dec 30 20:35:13 2011	(r229023)
@@ -47,18 +47,14 @@ typedef long sig_atomic_t;
 #include <machine/trap.h>	/* codes for SIGILL, SIGFPE */
 
 /*
- * Only the kernel should need these old type definitions.
- */
-/*
  * Information pushed on stack when a signal is delivered.
  * This is used by the kernel to restore state following
  * execution of the signal handler.  It is also made available
  * to the handler to allow it to restore state properly if
  * a non-standard exit is performed.
- */
-/*
- * The sequence of the fields/registers in struct sigcontext should match
- * those in mcontext_t.
+ *
+ * The sequence of the fields/registers after sc_mask in struct
+ * sigcontext must match those in mcontext_t and struct trapframe.
  */
 struct sigcontext {
 	struct __sigset sc_mask;	/* signal mask to restore */
@@ -93,8 +89,8 @@ struct sigcontext {
 	long	sc_ss;
 	long	sc_len;			/* sizeof(mcontext_t) */
 	/*
-	 * XXX - See <machine/ucontext.h> and <machine/fpu.h> for
-	 *       the following fields.
+	 * See <machine/ucontext.h> and <machine/fpu.h> for the following
+	 * fields.
 	 */
 	long	sc_fpformat;
 	long	sc_ownedfp;

Modified: stable/9/sys/amd64/include/ucontext.h
==============================================================================
--- stable/9/sys/amd64/include/ucontext.h	Fri Dec 30 20:24:52 2011	(r229022)
+++ stable/9/sys/amd64/include/ucontext.h	Fri Dec 30 20:35:13 2011	(r229023)
@@ -41,12 +41,13 @@
 
 typedef struct __mcontext {
 	/*
-	 * The first 24 fields must match the definition of
-	 * sigcontext. So that we can support sigcontext
-	 * and ucontext_t at the same time.
+	 * The definition of mcontext_t must match the layout of
+	 * struct sigcontext after the sc_mask member.  This is so
+	 * that we can support sigcontext and ucontext_t at the same
+	 * time.
 	 */
-	__register_t	mc_onstack;		/* XXX - sigcontext compat. */
-	__register_t	mc_rdi;			/* machine state (struct trapframe) */
+	__register_t	mc_onstack;	/* XXX - sigcontext compat. */
+	__register_t	mc_rdi;		/* machine state (struct trapframe) */
 	__register_t	mc_rsi;
 	__register_t	mc_rdx;
 	__register_t	mc_rcx;

Modified: stable/9/sys/i386/i386/trap.c
==============================================================================
--- stable/9/sys/i386/i386/trap.c	Fri Dec 30 20:24:52 2011	(r229022)
+++ stable/9/sys/i386/i386/trap.c	Fri Dec 30 20:35:13 2011	(r229023)
@@ -1065,9 +1065,8 @@ cpu_fetch_syscall_args(struct thread *td
 #include "../../kern/subr_syscall.c"
 
 /*
- *	syscall -	system call request C handler
- *
- *	A system call is essentially treated as a trap.
+ * syscall - system call request C handler.  A system call is
+ * essentially treated as a trap by reusing the frame layout.
  */
 void
 syscall(struct trapframe *frame)

Modified: stable/9/sys/i386/include/signal.h
==============================================================================
--- stable/9/sys/i386/include/signal.h	Fri Dec 30 20:24:52 2011	(r229022)
+++ stable/9/sys/i386/include/signal.h	Fri Dec 30 20:35:13 2011	(r229023)
@@ -46,16 +46,17 @@ typedef int sig_atomic_t;
 #include <machine/trap.h>	/* codes for SIGILL, SIGFPE */
 
 /*
- * Only the kernel should need these old type definitions.
- */
-#if defined(_KERNEL) && defined(COMPAT_43)
-/*
  * Information pushed on stack when a signal is delivered.
  * This is used by the kernel to restore state following
  * execution of the signal handler.  It is also made available
  * to the handler to allow it to restore state properly if
  * a non-standard exit is performed.
  */
+
+#if defined(_KERNEL) && defined(COMPAT_43)
+/*
+ * Only the kernel should need these old type definitions.
+ */
 struct osigcontext {
 	int	sc_onstack;		/* sigstack state to restore */
 	osigset_t sc_mask;		/* signal mask to restore */
@@ -83,7 +84,7 @@ struct osigcontext {
 
 /*
  * The sequence of the fields/registers in struct sigcontext should match
- * those in mcontext_t.
+ * those in mcontext_t and struct trapframe.
  */
 struct sigcontext {
 	struct __sigset sc_mask;	/* signal mask to restore */
@@ -109,8 +110,8 @@ struct sigcontext {
 	int	sc_ss;
 	int	sc_len;			/* sizeof(mcontext_t) */
 	/*
-	 * XXX - See <machine/ucontext.h> and <machine/npx.h> for
-	 *       the following fields.
+	 * See <machine/ucontext.h> and <machine/npx.h> for
+	 * the following fields.
 	 */
 	int	sc_fpformat;
 	int	sc_ownedfp;

Modified: stable/9/sys/i386/include/ucontext.h
==============================================================================
--- stable/9/sys/i386/include/ucontext.h	Fri Dec 30 20:24:52 2011	(r229022)
+++ stable/9/sys/i386/include/ucontext.h	Fri Dec 30 20:35:13 2011	(r229023)
@@ -33,9 +33,9 @@
 
 typedef struct __mcontext {
 	/*
-	 * The first 20 fields must match the definition of
-	 * sigcontext. So that we can support sigcontext
-	 * and ucontext_t at the same time.
+	 * The definition of mcontext_t shall match the layout of
+	 * struct sigcontext after the sc_mask member.  So that we can
+	 * support sigcontext and ucontext_t at the same time.
 	 */
 	__register_t	mc_onstack;	/* XXX - sigcontext compat. */
 	__register_t	mc_gs;		/* machine state (struct trapframe) */