[PATCH] i386: rationalize paravirt wrappers

paravirt.c used to implement native versions of all low-level
functions.  Far cleaner is to have the native versions exposed in the
headers and as inline native_XXX, and if !CONFIG_PARAVIRT, then simply
#define XXX native_XXX.

There are several nice side effects:

1) write_dt_entry() now takes the correct "struct Xgt_desc_struct *"
   not "void *".

2) load_TLS is reintroduced to the for loop, not manually unrolled
   with a #error in case the bounds ever change.

3) Macros become inlines, with type checking.

4) Access to the native versions is trivial for KVM, lguest, Xen and
   others who might want it.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@muc.de>
Cc: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 56 insertions, 26 deletions

diff --git a/include/asm-i386/desc.h b/include/asm-i386/desc.h
index a75ae6b..13f701e 100644
--- a/include/asm-i386/desc.h
+++ b/include/asm-i386/desc.h
@@ -57,45 +57,33 @@ static inline void pack_gate(__u32 *a, __u32 *b,
 #ifdef CONFIG_PARAVIRT
 #include <asm/paravirt.h>
 #else
-#define load_TR_desc() __asm__ __volatile__("ltr %w0"::"q" (GDT_ENTRY_TSS*8))
-
-#define load_gdt(dtr) __asm__ __volatile("lgdt %0"::"m" (*dtr))
-#define load_idt(dtr) __asm__ __volatile("lidt %0"::"m" (*dtr))
+#define load_TR_desc() native_load_tr_desc()
+#define load_gdt(dtr) native_load_gdt(dtr)
+#define load_idt(dtr) native_load_idt(dtr)
 #define load_tr(tr) __asm__ __volatile("ltr %0"::"m" (tr))
 #define load_ldt(ldt) __asm__ __volatile("lldt %0"::"m" (ldt))
 
-#define store_gdt(dtr) __asm__ ("sgdt %0":"=m" (*dtr))
-#define store_idt(dtr) __asm__ ("sidt %0":"=m" (*dtr))
-#define store_tr(tr) __asm__ ("str %0":"=m" (tr))
+#define store_gdt(dtr) native_store_gdt(dtr)
+#define store_idt(dtr) native_store_idt(dtr)
+#define store_tr(tr) (tr = native_store_tr())
 #define store_ldt(ldt) __asm__ ("sldt %0":"=m" (ldt))
 
-#if TLS_SIZE != 24
-# error update this code.
-#endif
-
-static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
-{
-#define C(i) get_cpu_gdt_table(cpu)[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i]
-	C(0); C(1); C(2);
-#undef C
-}
+#define load_TLS(t, cpu) native_load_tls(t, cpu)
+#define set_ldt native_set_ldt
 
 #define write_ldt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
 #define write_gdt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
 #define write_idt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
+#endif
 
-static inline void write_dt_entry(void *dt, int entry, __u32 entry_a, __u32 entry_b)
+static inline void write_dt_entry(struct desc_struct *dt,
+				  int entry, u32 entry_low, u32 entry_high)
 {
-	__u32 *lp = (__u32 *)((char *)dt + entry*8);
-	*lp = entry_a;
-	*(lp+1) = entry_b;
+	dt[entry].a = entry_low;
+	dt[entry].b = entry_high;
 }
 
-#define set_ldt native_set_ldt
-#endif /* CONFIG_PARAVIRT */
-
-static inline fastcall void native_set_ldt(const void *addr,
-					   unsigned int entries)
+static inline void native_set_ldt(const void *addr, unsigned int entries)
 {
 	if (likely(entries == 0))
 		__asm__ __volatile__("lldt %w0"::"q" (0));
@@ -111,6 +99,48 @@ static inline fastcall void native_set_ldt(const void *addr,
 	}
 }
 
+
+static inline void native_load_tr_desc(void)
+{
+	asm volatile("ltr %w0"::"q" (GDT_ENTRY_TSS*8));
+}
+
+static inline void native_load_gdt(const struct Xgt_desc_struct *dtr)
+{
+	asm volatile("lgdt %0"::"m" (*dtr));
+}
+
+static inline void native_load_idt(const struct Xgt_desc_struct *dtr)
+{
+	asm volatile("lidt %0"::"m" (*dtr));
+}
+
+static inline void native_store_gdt(struct Xgt_desc_struct *dtr)
+{
+	asm ("sgdt %0":"=m" (*dtr));
+}
+
+static inline void native_store_idt(struct Xgt_desc_struct *dtr)
+{
+	asm ("sidt %0":"=m" (*dtr));
+}
+
+static inline unsigned long native_store_tr(void)
+{
+	unsigned long tr;
+	asm ("str %0":"=r" (tr));
+	return tr;
+}
+
+static inline void native_load_tls(struct thread_struct *t, unsigned int cpu)
+{
+	unsigned int i;
+	struct desc_struct *gdt = get_cpu_gdt_table(cpu);
+
+	for (i = 0; i < GDT_ENTRY_TLS_ENTRIES; i++)
+		gdt[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i];
+}
+
 static inline void _set_gate(int gate, unsigned int type, void *addr, unsigned short seg)
 {
 	__u32 a, b;