[PATCH] Re: Limit in set_thread_area

the attached patch does the set_thread_area parameter simplification - it
also cleans up some other TLS issues, it removes the tls_* fields from the
thread_struct, and removes the now unused page-granularity flag.

arch/i386/kernel/process.c

@@ -831,34 +831,27 @@ unsigned long get_wchan(struct task_struct *p)
 /*
  * Set the Thread-Local Storage area:
  */
-asmlinkage int sys_set_thread_area(unsigned int base, unsigned int limit, unsigned int flags)
+asmlinkage int sys_set_thread_area(unsigned long base, unsigned long flags)
 {
 	struct thread_struct *t = &current->thread;
-	int limit_in_pages = 0, writable = 0;
+	int writable = 0;
 	int cpu;
 
 	/* do not allow unused flags */
 	if (flags & ~TLS_FLAGS_MASK)
 		return -EINVAL;
 
-	/* check limit */
-	if (limit & 0xfff00000)
-		return -EINVAL;
-
 	/*
 	 * Clear the TLS?
 	 */
 	if (flags & TLS_FLAG_CLEAR) {
 		cpu = get_cpu();
-		t->tls_base = t->tls_limit = t->tls_flags = 0;
         	t->tls_desc.a = t->tls_desc.b = 0;
 		load_TLS_desc(t, cpu);
 		put_cpu();
 		return 0;
 	}
 
-	if (flags & TLS_FLAG_LIMIT_IN_PAGES)
-		limit_in_pages = 1;
 	if (flags & TLS_FLAG_WRITABLE)
 		writable = 1;
 
@@ -866,15 +859,12 @@ asmlinkage int sys_set_thread_area(unsigned int base, unsigned int limit, unsign
 	 * We must not get preempted while modifying the TLS.
 	 */
 	cpu = get_cpu();
-	t->tls_base = base;
-	t->tls_limit = limit;
-	t->tls_flags = flags;
 
-        t->tls_desc.a = ((base & 0x0000ffff) << 16) | (limit & 0x0ffff);
+        t->tls_desc.a = ((base & 0x0000ffff) << 16) | 0xffff;
 
         t->tls_desc.b = (base & 0xff000000) | ((base & 0x00ff0000) >> 16) |
-                  (limit & 0xf0000) | (writable << 9) | (1 << 15) |
-		  (1 << 22) | (limit_in_pages << 23) | 0x7000;
+				0xf0000 | (writable << 9) | (1 << 15) |
+					(1 << 22) | (1 << 23) | 0x7000;
 
 	load_TLS_desc(t, cpu);
 	put_cpu();

include/asm-i386/desc.h

@@ -86,11 +86,10 @@ static inline void set_ldt_desc(unsigned int cpu, void *addr, unsigned int size)
 	_set_tssldt_desc(&cpu_gdt_table[cpu][LDT_ENTRY], (int)addr, ((size << 3)-1), 0x82);
 }
 
-#define TLS_FLAGS_MASK			0x00000007
+#define TLS_FLAGS_MASK			0x00000003
 
-#define TLS_FLAG_LIMIT_IN_PAGES		0x00000001
-#define TLS_FLAG_WRITABLE		0x00000002
-#define TLS_FLAG_CLEAR			0x00000004
+#define TLS_FLAG_WRITABLE		0x00000001
+#define TLS_FLAG_CLEAR			0x00000002
 
 static inline void load_TLS_desc(struct thread_struct *t, unsigned int cpu)
 {

include/asm-i386/processor.h

@@ -376,8 +376,7 @@ struct thread_struct {
 	unsigned long		v86flags, v86mask, v86mode, saved_esp0;
 /* IO permissions */
 	unsigned long	*ts_io_bitmap;
-/* TLS info and cached descriptor */
-	unsigned int tls_base, tls_limit, tls_flags;
+/* TLS cached descriptor */
 	struct desc_struct tls_desc;
 };