x86, tls: Interpret an all-zero struct user_desc as "no segment"

[pandora-kernel.git] / arch / x86 / include / asm / desc.h

diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index 41935fa..3225868 100644 (file)
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -248,7 +248,8 @@ static inline void native_load_tls(struct thread_struct *t, unsigned int cpu)
                gdt[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i];
 }
 
-#define _LDT_empty(info)                               \
+/* This intentionally ignores lm, since 32-bit apps don't have that field. */
+#define LDT_empty(info)                                        \
        ((info)->base_addr              == 0    &&      \
         (info)->limit                  == 0    &&      \
         (info)->contents               == 0    &&      \
@@ -258,11 +259,18 @@ static inline void native_load_tls(struct thread_struct *t, unsigned int cpu)
         (info)->seg_not_present        == 1    &&      \
         (info)->useable                == 0)
 
-#ifdef CONFIG_X86_64
-#define LDT_empty(info) (_LDT_empty(info) && ((info)->lm == 0))
-#else
-#define LDT_empty(info) (_LDT_empty(info))
-#endif
+/* Lots of programs expect an all-zero user_desc to mean "no segment at all". */
+static inline bool LDT_zero(const struct user_desc *info)
+{
+       return (info->base_addr         == 0 &&
+               info->limit             == 0 &&
+               info->contents          == 0 &&
+               info->read_exec_only    == 0 &&
+               info->seg_32bit         == 0 &&
+               info->limit_in_pages    == 0 &&
+               info->seg_not_present   == 0 &&
+               info->useable           == 0);
+}
 
 static inline void clear_LDT(void)
 {