The following commit has been merged in the linux branch: commit 71999d9862e667f1fd14f8fbfa0cce6d855bad3f Author: Jeremy Fitzhardinge jeremy@goop.org Date: Mon Oct 12 16:32:43 2009 -0700
x86/paravirt: Use normal calling sequences for irq enable/disable
Bastian Blank reported a boot crash with stackprotector enabled, and debugged it back to edx register corruption.
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.
This fixes some residual bugs in the old implementations which left edx liable to inadvertent clobbering. Also, fix some bugs in __PVOP_VCALLEESAVE which were revealed by actual use.
Reported-by: Bastian Blank bastian@waldi.eu.org Signed-off-by: Jeremy Fitzhardinge jeremy.fitzhardinge@citrix.com Cc: Stable Kernel stable@kernel.org Cc: Xen-devel xen-devel@lists.xensource.com LKML-Reference: 4AD3BC9B.7040501@goop.org Signed-off-by: Ingo Molnar mingo@elte.hu
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index 8aebcc4..efb3899 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -840,42 +840,22 @@ 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 dd0f5b3..9357473 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -494,10 +494,11 @@ int paravirt_disable_iospace(void); #define EXTRA_CLOBBERS #define VEXTRA_CLOBBERS #else /* CONFIG_X86_64 */ +/* [re]ax isn't an arg, but the return val */ #define PVOP_VCALL_ARGS \ unsigned long __edi = __edi, __esi = __esi, \ - __edx = __edx, __ecx = __ecx -#define PVOP_CALL_ARGS PVOP_VCALL_ARGS, __eax + __edx = __edx, __ecx = __ecx, __eax = __eax +#define PVOP_CALL_ARGS PVOP_VCALL_ARGS
#define PVOP_CALL_ARG1(x) "D" ((unsigned long)(x)) #define PVOP_CALL_ARG2(x) "S" ((unsigned long)(x)) @@ -509,6 +510,7 @@ int paravirt_disable_iospace(void); "=c" (__ecx) #define PVOP_CALL_CLOBBERS PVOP_VCALL_CLOBBERS, "=a" (__eax)
+/* void functions are still allowed [re]ax for scratch */ #define PVOP_VCALLEE_CLOBBERS "=a" (__eax) #define PVOP_CALLEE_CLOBBERS PVOP_VCALLEE_CLOBBERS
@@ -583,8 +585,8 @@ 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__)