x86, paravirt: Replace GET_CR2_INTO_RCX with GET_CR2_INTO_RAX

GET_CR2_INTO_RCX is asinine: it is only used in one place, the actual
paravirt call returns the value in %rax, not %rcx; and the one place
that wants it wants the result in %r9.  We actually generate as a
result of this call:

       call ...
       movq %rax, %rcx
       xorq %rax, %rax		/* this value isn't even used... */
       movq %rcx, %r9

At least make the macro do what the paravirt call does, which is put
the value into %rax.

Nevermind the fact that the macro clobbers all the volatile registers.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1334794610-5546-4-git-send-email-hpa@zytor.com
Cc: Glauber de Oliveira Costa <glommer@parallels.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index adf52e85d551..d1e112c8b577 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -23,8 +23,9 @@
 #ifdef CONFIG_PARAVIRT
 #include <asm/asm-offsets.h>
 #include <asm/paravirt.h>
+#define GET_CR2_INTO(reg) GET_CR2_INTO_RAX ; movq %rax, reg
 #else
-#define GET_CR2_INTO_RCX movq %cr2, %rcx
+#define GET_CR2_INTO(reg) movq %cr2, reg
 #endif
 
 /* we are not able to switch in one step to the final KERNEL ADDRESS SPACE
@@ -286,8 +287,7 @@ ENTRY(early_idt_handler)
         cmpl $2,early_recursion_flag(%rip)
         jz  1f
         incl early_recursion_flag(%rip)
-        GET_CR2_INTO_RCX
-        movq %rcx,%r9
+        GET_CR2_INTO(%r9)
         xorl %r8d,%r8d          # zero for error code
         movl %esi,%ecx          # get vector number
         # Test %ecx against mask of vectors that push error code.