Preserve %fs and %gs across context switches. This has a relatively low

cost since it is only done in cpu_switch(), not for every exception.
The extra state is kept in the pcb, and handled much like the npx state,
with similar deficiencies (the state is not preserved across signal
handlers, and error handling loses state).

1 files changed, 13 insertions, 1 deletions

diff --git a/sys/amd64/include/reg.h b/sys/amd64/include/reg.h
index c896fe5..5d36f27 100644
--- a/sys/amd64/include/reg.h
+++ b/sys/amd64/include/reg.h
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)reg.h	5.5 (Berkeley) 1/18/91
- *	$Id: reg.h,v 1.13 1997/02/22 09:35:07 peter Exp $
+ *	$Id: reg.h,v 1.14 1997/06/07 00:49:45 bde Exp $
  */
 
 #ifndef _MACHINE_REG_H_
@@ -69,6 +69,16 @@
 #define	tSS	(16)
 
 /*
+ * Indices for registers in `struct regs' only.
+ *
+ * Some registers live in the pcb and are only in an "array" with the
+ * other registers in application interfaces that copy all the registers
+ * to or from a `struct regs'.
+ */
+#define	tFS	(17)
+#define	tGS	(18)
+
+/*
  * Register set accessible via /proc/$pid/regs and PT_{SET,GET}REGS.
  */
 struct reg {
@@ -89,6 +99,8 @@ struct reg {
 	unsigned int	r_eflags;
 	unsigned int	r_esp;
 	unsigned int	r_ss;
+	unsigned int	r_fs;
+	unsigned int	r_gs;
 };
 
 /*