path: root/arch/x86/include/asm
diff options
authorArnd Bergmann <>2019-03-04 21:52:39 +0100
committerJuergen Gross <>2019-03-05 12:07:32 +0100
commitb1ddd406cd1e9bb51fa90d03ee562c832e38eb52 (patch)
tree01ada3c648984bced35c52dcca18c03df594e2f6 /arch/x86/include/asm
parent85eb278c1899f78d1429b45ffa84039d9011cb55 (diff)
xen: remove pre-xen3 fallback handlers
The legacy hypercall handlers were originally added with a comment explaining that "copying the argument structures in HYPERVISOR_event_channel_op() and HYPERVISOR_physdev_op() into the local variable is sufficiently safe" and only made sure to not write past the end of the argument structure, the checks in linux/string.h disagree with that, when link-time optimizations are used: In function 'memcpy', inlined from 'pirq_query_unmask' at drivers/xen/fallback.c:53:2, inlined from '__startup_pirq' at drivers/xen/events/events_base.c:529:2, inlined from 'restore_pirqs' at drivers/xen/events/events_base.c:1439:3, inlined from 'xen_irq_resume' at drivers/xen/events/events_base.c:1581:2: include/linux/string.h:350:3: error: call to '__read_overflow2' declared with attribute error: detected read beyond size of object passed as 2nd parameter __read_overflow2(); ^ Further research turned out that only Xen 3.0.2 or earlier required the fallback at all, while all versions in use today don't need it. As far as I can tell, it is not even possible to run a mainline kernel on those old Xen releases, at the time when they were in use, only a patched kernel was supported anyway. Fixes: cf47a83fb06e ("xen/hypercall: fix hypercall fallback code for very old hypervisors") Reviewed-by: Boris Ostrovsky <> Cc: Jan Beulich <> Signed-off-by: Arnd Bergmann <> Signed-off-by: Juergen Gross <>
Diffstat (limited to 'arch/x86/include/asm')
1 files changed, 2 insertions, 11 deletions
diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h
index ef05bea7010d..de6f0d59a24f 100644
--- a/arch/x86/include/asm/xen/hypercall.h
+++ b/arch/x86/include/asm/xen/hypercall.h
@@ -332,15 +332,11 @@ HYPERVISOR_update_va_mapping(unsigned long va, pte_t new_val,
return _hypercall4(int, update_va_mapping, va,
new_val.pte, new_val.pte >> 32, flags);
-extern int __must_check xen_event_channel_op_compat(int, void *);
static inline int
HYPERVISOR_event_channel_op(int cmd, void *arg)
- int rc = _hypercall2(int, event_channel_op, cmd, arg);
- if (unlikely(rc == -ENOSYS))
- rc = xen_event_channel_op_compat(cmd, arg);
- return rc;
+ return _hypercall2(int, event_channel_op, cmd, arg);
static inline int
@@ -355,15 +351,10 @@ HYPERVISOR_console_io(int cmd, int count, char *str)
return _hypercall3(int, console_io, cmd, count, str);
-extern int __must_check xen_physdev_op_compat(int, void *);
static inline int
HYPERVISOR_physdev_op(int cmd, void *arg)
- int rc = _hypercall2(int, physdev_op, cmd, arg);
- if (unlikely(rc == -ENOSYS))
- rc = xen_physdev_op_compat(cmd, arg);
- return rc;
+ return _hypercall2(int, physdev_op, cmd, arg);
static inline int