2.6.31-stable review patch. If anyone has any objections, please let us know.
------------------
From: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
commit 71999d9862e667f1fd14f8fbfa0cce6d855bad3f upstream.
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@xxxxxxxxxxxx>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
Cc: Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
LKML-Reference: <4AD3BC9B.7040501@xxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
arch/x86/include/asm/paravirt.h | 38 ++++++++++----------------------------
1 file changed, 10 insertions(+), 28 deletions(-)
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -528,10 +528,11 @@ 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))
@@ -543,6 +544,7 @@ 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
@@ -617,8 +619,8 @@ 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__)
@@ -1565,42 +1567,22 @@ extern struct paravirt_patch_site __para
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)
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