On 10/05/09 20:30, Bastian Blank wrote:
> The original version saves ecx, but not edx. Both are official
> caller-saved registers.
>
Hm. It doesn't save edx because that can be half of a 64-bit return
value, and in general both eax and edx are marked clobbered. Except one
place; does the patch below help?
>> Besides, most of the code in that file isn't used unless you're using a
>> very old version of Xen; it will generally prefer to use the ones in
>> xen-asm_X.S.
>>
> Well, my call stack say something different. It crashs during early
> startup without a console. The modifications to the function pointers is
> done much later.
You're right. But you're holding out on me; can I see your backtrace?
And the disassembly of the troublesome code (both the Xen function and
the calling function)?
Thanks,
J
From: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
Date: Tue, 6 Oct 2009 11:36:44 -0700
Subject: [PATCH] x86/paravirt: use normal calling sequences for irq
enable/disable etc
For historical reasons irq enable/disable/save/restore had special
calling sequences to make them more efficient. With the more
recent introduction of higher-level and more general optimisations
this is no longer necessary so we can just use the normal PVOP_
macros.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index e19ffe3..e8420a2 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -863,42 +863,22 @@ static __always_inline void __raw_spin_unlock(struct
raw_spinlock *lock)
static inline unsigned long __raw_local_save_flags(void)
{
- unsigned long f;
-
- asm volatile(paravirt_alt(PARAVIRT_CALL)
- : "=a"(f)
- : paravirt_type(pv_irq_ops.save_fl),
- paravirt_clobber(CLBR_EAX)
- : "memory", "cc");
- return f;
+ return PVOP_CALLEE0(unsigned long, pv_irq_ops.save_fl);
}
static inline void raw_local_irq_restore(unsigned long f)
{
- asm volatile(paravirt_alt(PARAVIRT_CALL)
- : "=a"(f)
- : PV_FLAGS_ARG(f),
- paravirt_type(pv_irq_ops.restore_fl),
- paravirt_clobber(CLBR_EAX)
- : "memory", "cc");
+ PVOP_VCALLEE1(pv_irq_ops.restore_fl, f);
}
static inline void raw_local_irq_disable(void)
{
- asm volatile(paravirt_alt(PARAVIRT_CALL)
- :
- : paravirt_type(pv_irq_ops.irq_disable),
- paravirt_clobber(CLBR_EAX)
- : "memory", "eax", "cc");
+ PVOP_VCALLEE0(pv_irq_ops.irq_disable);
}
static inline void raw_local_irq_enable(void)
{
- asm volatile(paravirt_alt(PARAVIRT_CALL)
- :
- : paravirt_type(pv_irq_ops.irq_enable),
- paravirt_clobber(CLBR_EAX)
- : "memory", "eax", "cc");
+ PVOP_VCALLEE0(pv_irq_ops.irq_enable);
}
static inline unsigned long __raw_local_irq_save(void)
diff --git a/arch/x86/include/asm/paravirt_types.h
b/arch/x86/include/asm/paravirt_types.h
index b9bb5e8..0b97706 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -612,8 +612,8 @@ int paravirt_disable_iospace(void);
VEXTRA_CLOBBERS, \
pre, post, ##__VA_ARGS__)
-#define __PVOP_VCALLEESAVE(rettype, op, pre, post, ...)
\
- ____PVOP_CALL(rettype, op.func, CLBR_RET_REG, \
+#define __PVOP_VCALLEESAVE(op, pre, post, ...) \
+ ____PVOP_VCALL(op.func, CLBR_RET_REG, \
PVOP_VCALLEE_CLOBBERS, , \
pre, post, ##__VA_ARGS__)
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