1 files changed, 25 insertions, 25 deletions

diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index a9c5cc851285..e3725a0f4327 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -307,30 +307,39 @@ default_entry:
         movl %eax,%cr0
 
 /*
- *      New page tables may be in 4Mbyte page mode and may
- *      be using the global pages. 
+ * We want to start out with EFLAGS unambiguously cleared. Some BIOSes leave
+ * bits like NT set. This would confuse the debugger if this code is traced. So
+ * initialize them properly now before switching to protected mode. That means
+ * DF in particular (even though we have cleared it earlier after copying the
+ * command line) because GCC expects it.
+ */
+        pushl $0
+        popfl
+
+/*
+ * New page tables may be in 4Mbyte page mode and may be using the global pages.
  *
- *      NOTE! If we are on a 486 we may have no cr4 at all!
- *      Specifically, cr4 exists if and only if CPUID exists
- *      and has flags other than the FPU flag set.
+ * NOTE! If we are on a 486 we may have no cr4 at all! Specifically, cr4 exists
+ * if and only if CPUID exists and has flags other than the FPU flag set.
  */
+        movl $-1,pa(X86_CPUID)          # preset CPUID level
         movl $X86_EFLAGS_ID,%ecx
         pushl %ecx
-        popfl
-        pushfl
-        popl %eax
-        pushl $0
-        popfl
+        popfl                           # set EFLAGS=ID
         pushfl
-        popl %edx
-        xorl %edx,%eax
-        testl %ecx,%eax
-        jz 6f                   # No ID flag = no CPUID = no CR4
+        popl %eax                       # get EFLAGS
+        testl $X86_EFLAGS_ID,%eax       # did EFLAGS.ID remained set?
+        jz 6f                           # hw disallowed setting of ID bit
+                                        # which means no CPUID and no CR4
+
+        xorl %eax,%eax
+        cpuid
+        movl %eax,pa(X86_CPUID)         # save largest std CPUID function
 
         movl $1,%eax
         cpuid
-        andl $~1,%edx           # Ignore CPUID.FPU
-        jz 6f                   # No flags or only CPUID.FPU = no CR4
+        andl $~1,%edx                   # Ignore CPUID.FPU
+        jz 6f                           # No flags or only CPUID.FPU = no CR4
 
         movl pa(mmu_cr4_features),%eax
         movl %eax,%cr4
@@ -378,14 +387,6 @@ default_entry:
         addl $__PAGE_OFFSET, %esp
 
 /*
- * Initialize eflags.  Some BIOS's leave bits like NT set.  This would
- * confuse the debugger if this code is traced.
- * XXX - best to initialize before switching to protected mode.
- */
-        pushl $0
-        popfl
-
-/*
  * start system 32-bit setup. We need to re-do some of the things done
  * in 16-bit mode for the "real" operations.
  */
@@ -461,7 +462,6 @@ is486:	movl $0x50022,%ecx	# set AM, WP, NE and MP
         xorl %eax,%eax                  # Clear LDT
         lldt %ax
 
-        cld                     # gcc2 wants the direction flag cleared at all times
         pushl $0                # fake return address for unwinder
         jmp *(initial_code)