- Merge savectx2() with savectx() and struct xpcb with struct pcb. [1]

savectx() is only used for panic dump (dumppcb) and kdb (stoppcbs).  Thus,
saving additional information does not hurt and it may be even beneficial.
Unfortunately, struct pcb has grown larger to accommodate more data.
Move 512-byte long pcb_user_save to the end of struct pcb while I am here.
- savectx() now saves FPU state unconditionally and copy it to the PCB of
FPU thread if necessary.  This gives panic dump and kdb a chance to take
a look at the current FPU state even if the FPU is "supposedly" not used.
- Resuming CPU now unconditionally reinitializes FPU.  If the saved FPU
state was irrelevant, it could be in an unknown state.

Suggested by:	bde [1]

1 files changed, 19 insertions, 22 deletions

diff --git a/sys/amd64/include/pcb.h b/sys/amd64/include/pcb.h
index aead8b7..4cc0240 100644
--- a/sys/amd64/include/pcb.h
+++ b/sys/amd64/include/pcb.h
@@ -44,7 +44,6 @@
 #include <machine/segments.h>
 
 struct pcb {
-	register_t	pcb_cr3;
 	register_t	pcb_r15;
 	register_t	pcb_r14;
 	register_t	pcb_r13;
@@ -55,6 +54,7 @@ struct pcb {
 	register_t	pcb_rip;
 	register_t	pcb_fsbase;
 	register_t	pcb_gsbase;
+	register_t	pcb_kgsbase;
 	u_long		pcb_flags;
 #define	PCB_DBREGS	0x02	/* process using debug registers */
 #define	PCB_KERNFPU	0x04	/* kernel uses fpu */
@@ -64,44 +64,41 @@ struct pcb {
 #define	PCB_32BIT	0x40	/* process has 32 bit context (segs etc) */
 #define	PCB_FULLCTX	0x80	/* full context restore on sysret */
 
-	u_int64_t	pcb_dr0;
-	u_int64_t	pcb_dr1;
-	u_int64_t	pcb_dr2;
-	u_int64_t	pcb_dr3;
-	u_int64_t	pcb_dr6;
-	u_int64_t	pcb_dr7;
+	register_t	pcb_cr0;
+	register_t	pcb_cr2;
+	register_t	pcb_cr3;
+	register_t	pcb_cr4;
+	register_t	pcb_dr0;
+	register_t	pcb_dr1;
+	register_t	pcb_dr2;
+	register_t	pcb_dr3;
+	register_t	pcb_dr6;
+	register_t	pcb_dr7;
 
-	struct	savefpu pcb_user_save;
 	uint16_t	pcb_initial_fpucw;
 
 	caddr_t		pcb_onfault; /* copyin/out fault recovery */
 
 	/* 32-bit segment descriptor */
-	struct user_segment_descriptor	pcb_gs32sd;
+	struct user_segment_descriptor pcb_gs32sd;
 	/* local tss, with i/o bitmap; NULL for common */
 	struct amd64tss *pcb_tssp;
 	struct	savefpu	*pcb_save;
 	char		pcb_full_iret;
-};
 
-struct xpcb {
-	struct pcb	xpcb_pcb;
-	register_t	xpcb_cr0;
-	register_t	xpcb_cr2;
-	register_t	xpcb_cr4;
-	register_t	xpcb_kgsbase;
-	struct region_descriptor xpcb_gdt;
-	struct region_descriptor xpcb_idt;
-	struct region_descriptor xpcb_ldt;
-	uint16_t	xpcb_tr;
+	struct region_descriptor pcb_gdt;
+	struct region_descriptor pcb_idt;
+	struct region_descriptor pcb_ldt;
+	uint16_t	pcb_tr;
+
+	struct	savefpu pcb_user_save;
 };
 
 #ifdef _KERNEL
 struct trapframe;
 
 void	makectx(struct trapframe *, struct pcb *);
-void	savectx(struct pcb *);
-int	savectx2(struct xpcb *);
+int	savectx(struct pcb *);
 #endif
 
 #endif /* _AMD64_PCB_H_ */