Messages in this thread Patch in this message | | | Date | Tue, 06 Oct 2009 12:01:12 -0700 | From | Jeremy Fitzhardinge <> | Subject | Re: [Xen-devel] Re: [PATCH] xen: Disable stack protector for irq helper |
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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@citrix.com> 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@citrix.com>
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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