amd64: add mc_tlsbase member to mcontext

Tested by:	pho
Reviewed by:	olce
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D50482

Author: kostikbel

sys/amd64/amd64/exec_machdep.c

@@ -635,6 +635,8 @@ get_mcontext(struct thread *td, mcontext_t *mcp, int flags)
 	mcp->mc_gsbase = pcb->pcb_gsbase;
 	mcp->mc_xfpustate = 0;
 	mcp->mc_xfpustate_len = 0;
+	mcp->mc_tlsbase = (pcb->pcb_flags & PCB_TLSBASE) != 0 ?
+	    pcb->pcb_tlsbase : 0;
 	bzero(mcp->mc_spare, sizeof(mcp->mc_spare));
 	return (0);
 }
@@ -709,6 +711,10 @@ set_mcontext(struct thread *td, mcontext_t *mcp)
 		pcb->pcb_fsbase = mcp->mc_fsbase;
 		pcb->pcb_gsbase = mcp->mc_gsbase;
 	}
+	if ((mcp->mc_flags & _MC_HASTLSBASE) != 0) {
+		pcb->pcb_tlsbase = mcp->mc_tlsbase;
+		set_pcb_flags(pcb, PCB_TLSBASE);
+	}
 	return (0);
 }
 

sys/x86/include/frame.h

@@ -152,6 +152,7 @@ struct trapframe {
 #define	TF_HASSEGS	0x1
 #define	TF_HASBASES	0x2
 #define	TF_HASFPXSTATE	0x4
+#define	TF_RESERV0	0x8 /* no tlsbase in the trapframe */
 #endif /* __amd64__ */
 
 #endif /* _MACHINE_FRAME_H_ */

sys/x86/include/ucontext.h

@@ -99,7 +99,9 @@ typedef struct __mcontext {
 #define	_MC_HASSEGS	0x1
 #define	_MC_HASBASES	0x2
 #define	_MC_HASFPXSTATE	0x4
-#define	_MC_FLAG_MASK	(_MC_HASSEGS | _MC_HASBASES | _MC_HASFPXSTATE)
+#define	_MC_HASTLSBASE	0x8
+#define	_MC_FLAG_MASK	(_MC_HASSEGS | _MC_HASBASES | _MC_HASFPXSTATE | \
+    _MC_HASTLSBASE)
 
 typedef struct __mcontext {
 	/*
@@ -158,7 +160,9 @@ typedef struct __mcontext {
 	__register_t	mc_xfpustate;
 	__register_t	mc_xfpustate_len;
 
-	long	mc_spare[4];
+	__register_t	mc_tlsbase;
+
+	long	mc_spare[3];
 } mcontext_t;
 #endif /* __amd64__ */