[PATCH] x86-64: Move cpu verification code to common file

o This patch moves the code to verify long mode and SSE to a common file.
  This code is now shared by trampoline.S, wakeup.S, boot/setup.S and
  boot/compressed/head.S

o So far we used to do very limited check in trampoline.S, wakeup.S and
  in 32bit entry point. Now all the entry paths are forced to do the
  exhaustive check, including SSE because verify_cpu is shared.

o I am keeping this patch as last in the x86 relocatable series because
  previous patches have got quite some amount of testing done and don't want
  to distrub that. So that if there is problem introduced by this patch, at
  least it can be easily isolated.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>

1 files changed, 3 insertions, 48 deletions

diff --git a/arch/x86_64/kernel/trampoline.S b/arch/x86_64/kernel/trampoline.S
index 13eee63c7bb..e7e2764c461 100644
--- a/arch/x86_64/kernel/trampoline.S
+++ b/arch/x86_64/kernel/trampoline.S
@@ -54,6 +54,8 @@ r_base = .
         movw    $(trampoline_stack_end - r_base), %sp
 
         call    verify_cpu              # Verify the cpu supports long mode
+        testl   %eax, %eax              # Check for return code
+        jnz     no_longmode
 
         mov     %cs, %ax
         movzx   %ax, %esi               # Find the 32bit trampoline location
@@ -121,57 +123,10 @@ startup_64:
         jmp     *%rax
 
         .code16
-verify_cpu:
-        pushl   $0                      # Kill any dangerous flags
-        popfl
-
-        /* minimum CPUID flags for x86-64 */
-        /* see http://www.x86-64.org/lists/discuss/msg02971.html */
-#define REQUIRED_MASK1 ((1<<0)|(1<<3)|(1<<4)|(1<<5)|(1<<6)|(1<<8)|\
-                           (1<<13)|(1<<15)|(1<<24)|(1<<25)|(1<<26))
-#define REQUIRED_MASK2 (1<<29)
-
-        pushfl                          # check for cpuid
-        popl    %eax
-        movl    %eax, %ebx
-        xorl    $0x200000,%eax
-        pushl   %eax
-        popfl
-        pushfl
-        popl    %eax
-        pushl   %ebx
-        popfl
-        cmpl    %eax, %ebx
-        jz      no_longmode
-
-        xorl    %eax, %eax              # See if cpuid 1 is implemented
-        cpuid
-        cmpl    $0x1, %eax
-        jb      no_longmode
-
-        movl    $0x01, %eax             # Does the cpu have what it takes?
-        cpuid
-        andl    $REQUIRED_MASK1, %edx
-        xorl    $REQUIRED_MASK1, %edx
-        jnz     no_longmode
-
-        movl    $0x80000000, %eax       # See if extended cpuid is implemented
-        cpuid
-        cmpl    $0x80000001, %eax
-        jb      no_longmode
-
-        movl    $0x80000001, %eax       # Does the cpu have what it takes?
-        cpuid
-        andl    $REQUIRED_MASK2, %edx
-        xorl    $REQUIRED_MASK2, %edx
-        jnz     no_longmode
-
-        ret                             # The cpu supports long mode
-
 no_longmode:
         hlt
         jmp no_longmode
-
+#include "verify_cpu.S"
 
         # Careful these need to be in the same 64K segment as the above;
 tidt: