From 4fc0f0e9471ec573ab2d44e7f462d996d614536e Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 6 Mar 2019 19:09:08 +0100 Subject: x86/uaccess, xen: Suppress SMAP warnings drivers/xen/privcmd.o: warning: objtool: privcmd_ioctl()+0x1414: call to hypercall_page() with UACCESS enabled Some Xen hypercalls allow parameter buffers in user land, so they need to set AC=1. Avoid the warning for those cases. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Juergen Gross Cc: Borislav Petkov Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: andrew.cooper3@citrix.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/xen/hypercall.h | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) (limited to 'arch/x86/include/asm/xen') diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h index de6f0d59a24f..580a909afad4 100644 --- a/arch/x86/include/asm/xen/hypercall.h +++ b/arch/x86/include/asm/xen/hypercall.h @@ -214,6 +214,22 @@ xen_single_call(unsigned int call, return (long)__res; } +static __always_inline void __xen_stac(void) +{ + /* + * Suppress objtool seeing the STAC/CLAC and getting confused about it + * calling random code with AC=1. + */ + asm volatile(ANNOTATE_IGNORE_ALTERNATIVE + ASM_STAC ::: "memory", "flags"); +} + +static __always_inline void __xen_clac(void) +{ + asm volatile(ANNOTATE_IGNORE_ALTERNATIVE + ASM_CLAC ::: "memory", "flags"); +} + static inline long privcmd_call(unsigned int call, unsigned long a1, unsigned long a2, @@ -222,9 +238,9 @@ privcmd_call(unsigned int call, { long res; - stac(); + __xen_stac(); res = xen_single_call(call, a1, a2, a3, a4, a5); - clac(); + __xen_clac(); return res; } @@ -421,9 +437,9 @@ HYPERVISOR_dm_op( domid_t dom, unsigned int nr_bufs, struct xen_dm_op_buf *bufs) { int ret; - stac(); + __xen_stac(); ret = _hypercall3(int, dm_op, dom, nr_bufs, bufs); - clac(); + __xen_clac(); return ret; } -- cgit v1.2.3