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Subject[PATCH 22/25 -v2] turn priviled operation into a macro
Date
under paravirt, read cr2 cannot be issued directly anymore.
So wrap it in a macro, defined to the operation itself in case
paravirt is off, but to something else if we have paravirt
in the game

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
arch/x86_64/kernel/head.S | 10 +++++++++-
1 files changed, 9 insertions(+), 1 deletions(-)
diff --git a/arch/x86_64/kernel/head.S b/arch/x86_64/kernel/head.S
index e89abcd..1bb6c55 100644
--- a/arch/x86_64/kernel/head.S
+++ b/arch/x86_64/kernel/head.S
@@ -18,6 +18,12 @@
#include <asm/page.h>
#include <asm/msr.h>
#include <asm/cache.h>
+#ifdef CONFIG_PARAVIRT
+#include <asm/asm-offsets.h>
+#include <asm/paravirt.h>
+#else
+#define GET_CR2_INTO_RCX mov %cr2, %rcx
+#endif

/* we are not able to switch in one step to the final KERNEL ADRESS SPACE
* because we need identity-mapped pages.
@@ -267,7 +273,9 @@ ENTRY(early_idt_handler)
xorl %eax,%eax
movq 8(%rsp),%rsi # get rip
movq (%rsp),%rdx
- movq %cr2,%rcx
+ /* When PARAVIRT is on, this operation may clobber rax. It is
+ something safe to do, because we've just zeroed rax. */
+ GET_CR2_INTO_RCX
leaq early_idt_msg(%rip),%rdi
call early_printk
cmpl $2,early_recursion_flag(%rip)
--
1.4.4.2
-
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