[Xen-devel] [PATCH 1/2] x86/paravirt: don't restore second return reg

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

Impact: bugfix

In the 32-bit calling convention, %eax:%edx is used to return 64-bit
values.  Don't save and restore %edx around wrapped functions, or they
can't return a full 64-bit result.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
---
arch/x86/include/asm/paravirt.h |    4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

===================================================================
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -1522,8 +1522,8 @@
#define PV_RESTORE_REGS "popl %edx; popl %ecx;"

/* save and restore all caller-save registers, except return value */
-#define PV_SAVE_ALL_CALLER_REGS PV_SAVE_REGS
-#define PV_RESTORE_ALL_CALLER_REGS PV_RESTORE_REGS
+#define PV_SAVE_ALL_CALLER_REGS                "pushl %ecx;"
+#define PV_RESTORE_ALL_CALLER_REGS     "popl  %ecx;"

#define PV_FLAGS_ARG "0"
#define PV_EXTRA_CLOBBERS



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