[PATCH] i386: inline assembler: cleanup and encapsulate descriptor and task register management

i386 inline assembler cleanup.

This change encapsulates descriptor and task register management.  Also,
it is possible to improve assembler generation in two cases; savesegment
may store the value in a register instead of a memory location, which
allows GCC to optimize stack variables into registers, and MOV MEM, SEG
is always a 16-bit write to memory, making the casting in math-emu
unnecessary.

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 12 insertions, 2 deletions

diff --git a/include/asm-i386/desc.h b/include/asm-i386/desc.h
index 11e67811a990..9a0b85a52e71 100644
--- a/include/asm-i386/desc.h
+++ b/include/asm-i386/desc.h
@@ -30,6 +30,16 @@ extern struct Xgt_desc_struct idt_descr, cpu_gdt_descr[NR_CPUS];
 #define load_TR_desc() __asm__ __volatile__("ltr %%ax"::"a" (GDT_ENTRY_TSS*8))
 #define load_LDT_desc() __asm__ __volatile__("lldt %%ax"::"a" (GDT_ENTRY_LDT*8))
 
+#define load_gdt(dtr) __asm__ __volatile("lgdt %0"::"m" (*dtr))
+#define load_idt(dtr) __asm__ __volatile("lidt %0"::"m" (*dtr))
+#define load_tr(tr) __asm__ __volatile("ltr %0"::"mr" (tr))
+#define load_ldt(ldt) __asm__ __volatile("lldt %0"::"mr" (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":"=mr" (tr))
+#define store_ldt(ldt) __asm__ ("sldt %0":"=mr" (ldt))
+
 /*
  * This is the ldt that every process will get unless we need
  * something other than this.
diff --git a/include/asm-i386/system.h b/include/asm-i386/system.h
index 8048a5e018cd..37fd2f8c7196 100644
--- a/include/asm-i386/system.h
+++ b/include/asm-i386/system.h
@@ -93,13 +93,13 @@ static inline unsigned long _get_base(char * addr)
                 ".align 4\n\t"                  \
                 ".long 1b,3b\n"                 \
                 ".previous"                     \
-                : :"m" (value))
+                : :"rm" (value))
 
 /*
  * Save a segment register away
  */
 #define savesegment(seg, value) \
-        asm volatile("mov %%" #seg ",%0":"=m" (value))
+        asm volatile("mov %%" #seg ",%0":"=rm" (value))
 
 /*
  * Clear and set 'TS' bit respectively