[PATCH] i386: i386 separate hardware-defined TSS from Linux additions

On Thu, 2007-03-29 at 13:16 +0200, Andi Kleen wrote:
> Please clean it up properly with two structs.

Not sure about this, now I've done it.  Running it here.

If you like it, I can do x86-64 as well.

==
lguest defines its own TSS struct because the "struct tss_struct"
contains linux-specific additions.  Andi asked me to split the struct
in processor.h.

Unfortunately it makes usage a little awkward.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andi Kleen <ak@suse.de>

1 files changed, 16 insertions, 8 deletions

diff --git a/include/asm-i386/processor.h b/include/asm-i386/processor.h
index 77e263267aa6..922260474646 100644
--- a/include/asm-i386/processor.h
+++ b/include/asm-i386/processor.h
@@ -291,7 +291,8 @@ typedef struct {
 
 struct thread_struct;
 
-struct tss_struct {
+/* This is the TSS defined by the hardware. */
+struct i386_hw_tss {
         unsigned short  back_link,__blh;
         unsigned long   esp0;
         unsigned short  ss0,__ss0h;
@@ -315,6 +316,11 @@ struct tss_struct {
         unsigned short  gs, __gsh;
         unsigned short  ldt, __ldth;
         unsigned short  trace, io_bitmap_base;
+} __attribute__((packed));
+
+struct tss_struct {
+        struct i386_hw_tss x86_tss;
+
         /*
          * The extra 1 is there because the CPU will access an
          * additional byte beyond the end of the IO permission
@@ -381,10 +387,12 @@ struct thread_struct {
  * be within the limit.
  */
 #define INIT_TSS  {                                                     \
-        .esp0           = sizeof(init_stack) + (long)&init_stack,       \
-        .ss0            = __KERNEL_DS,                                  \
-        .ss1            = __KERNEL_CS,                                  \
-        .io_bitmap_base = INVALID_IO_BITMAP_OFFSET,                     \
+        .x86_tss = {                                                    \
+                .esp0           = sizeof(init_stack) + (long)&init_stack, \
+                .ss0            = __KERNEL_DS,                          \
+                .ss1            = __KERNEL_CS,                          \
+                .io_bitmap_base = INVALID_IO_BITMAP_OFFSET,             \
+         },                                                             \
         .io_bitmap      = { [ 0 ... IO_BITMAP_LONGS] = ~0 },            \
 }
 
@@ -493,10 +501,10 @@ static inline void rep_nop(void)
 
 static inline void native_load_esp0(struct tss_struct *tss, struct thread_struct *thread)
 {
-        tss->esp0 = thread->esp0;
+        tss->x86_tss.esp0 = thread->esp0;
         /* This can only happen when SEP is enabled, no need to test "SEP"arately */
-        if (unlikely(tss->ss1 != thread->sysenter_cs)) {
-                tss->ss1 = thread->sysenter_cs;
+        if (unlikely(tss->x86_tss.ss1 != thread->sysenter_cs)) {
+                tss->x86_tss.ss1 = thread->sysenter_cs;
                 wrmsr(MSR_IA32_SYSENTER_CS, thread->sysenter_cs, 0);
         }
 }