From c1d476c9316f2c96a976a3e20893ab8a3c73a131 Mon Sep 17 00:00:00 2001
From: peter <peter@FreeBSD.org>
Date: Thu, 14 Apr 2005 00:44:07 +0000
Subject: Adapt the libpthread patch for using i386_set_gsbase() to libthr.

---
 lib/libthr/arch/i386/i386/pthread_md.c    | 47 ++++++++++++++++++++++---------
 lib/libthr/arch/i386/include/pthread_md.h | 10 +++++--
 2 files changed, 41 insertions(+), 16 deletions(-)

diff --git a/lib/libthr/arch/i386/i386/pthread_md.c b/lib/libthr/arch/i386/i386/pthread_md.c
index e0adb25..d17343c 100644
--- a/lib/libthr/arch/i386/i386/pthread_md.c
+++ b/lib/libthr/arch/i386/i386/pthread_md.c
@@ -35,14 +35,18 @@
 
 #include "pthread_md.h"
 
+int _thr_using_setbase;
+
 struct tcb *
 _tcb_ctor(struct pthread *thread, int initial)
 {
 #ifndef COMPAT_32BIT
 	union descriptor ldt;
+	void *base;
 #endif
 	struct tcb *tcb;
 	void *oldtls;
+	int error;
 
 	if (initial)
 		__asm __volatile("movl %%gs:0, %0" : "=r" (oldtls));
@@ -53,20 +57,35 @@ _tcb_ctor(struct pthread *thread, int initial)
 	if (tcb) {
 		tcb->tcb_thread = thread;
 #ifndef COMPAT_32BIT
-		ldt.sd.sd_hibase = (unsigned int)tcb >> 24;
-		ldt.sd.sd_lobase = (unsigned int)tcb & 0xFFFFFF;
-		ldt.sd.sd_hilimit = (sizeof(struct tcb) >> 16) & 0xF;
-		ldt.sd.sd_lolimit = sizeof(struct tcb) & 0xFFFF;
-		ldt.sd.sd_type = SDT_MEMRWA;
-		ldt.sd.sd_dpl = SEL_UPL;
-		ldt.sd.sd_p = 1;
-		ldt.sd.sd_xx = 0;
-		ldt.sd.sd_def32 = 1;
-		ldt.sd.sd_gran = 0;	/* no more than 1M */
-		tcb->tcb_ldt = i386_set_ldt(LDT_AUTO_ALLOC, &ldt, 1);
-		if (tcb->tcb_ldt < 0) {
-			_rtld_free_tls(tcb, sizeof(struct tcb), 16);
-			tcb = NULL;
+		tcb->tcb_ldt = -1;
+		switch (_thr_using_setbase) {
+		case 1:	/* use i386_set_gsbase() in _kcb_set */
+			break;
+		case 0:	/* Untested, try the get/set_gsbase routines once */
+			error = i386_get_gsbase(&base);
+			if (error == 0) {
+				_thr_using_setbase = 1;
+				break;
+			}
+			/* fall through */
+		case 2:	/* Use the user_ldt code, we must have an old kernel */
+			_thr_using_setbase = 2;
+			ldt.sd.sd_hibase = (unsigned int)tcb >> 24;
+			ldt.sd.sd_lobase = (unsigned int)tcb & 0xFFFFFF;
+			ldt.sd.sd_hilimit = (sizeof(struct tcb) >> 16) & 0xF;
+			ldt.sd.sd_lolimit = sizeof(struct tcb) & 0xFFFF;
+			ldt.sd.sd_type = SDT_MEMRWA;
+			ldt.sd.sd_dpl = SEL_UPL;
+			ldt.sd.sd_p = 1;
+			ldt.sd.sd_xx = 0;
+			ldt.sd.sd_def32 = 1;
+			ldt.sd.sd_gran = 0;	/* no more than 1M */
+			tcb->tcb_ldt = i386_set_ldt(LDT_AUTO_ALLOC, &ldt, 1);
+			if (tcb->tcb_ldt < 0) {
+				_rtld_free_tls(tcb, sizeof(struct tcb), 16);
+				tcb = NULL;
+			}
+			break;
 		}
 #endif
 	}
diff --git a/lib/libthr/arch/i386/include/pthread_md.h b/lib/libthr/arch/i386/include/pthread_md.h
index 721ddac..ac3cc9c 100644
--- a/lib/libthr/arch/i386/include/pthread_md.h
+++ b/lib/libthr/arch/i386/include/pthread_md.h
@@ -39,6 +39,8 @@
 
 #define	DTV_OFFSET		offsetof(struct tcb, tcb_dtv)
 
+extern int _thr_using_setbase;
+
 /*
  * Variant II tcb, first two members are required by rtld,
  * %gs points to the structure.
@@ -88,8 +90,12 @@ _tcb_set(struct tcb *tcb)
 #ifndef COMPAT_32BIT
 	int val;
 
-	val = (tcb->tcb_ldt << 3) | 7;
-	__asm __volatile("movl %0, %%gs" : : "r" (val));
+ 	if (_thr_using_setbase == 1) {
+ 		i386_set_gsbase(tcb);
+ 	} else {
+		val = (tcb->tcb_ldt << 3) | 7;
+		__asm __volatile("movl %0, %%gs" : : "r" (val));
+ 	}
 #else
 	_amd64_set_gsbase(tcb);
 #endif
-- 
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