Commit-ID: 4fc0f0e9471ec573ab2d44e7f462d996d614536e
Gitweb: https://git.kernel.org/tip/4fc0f0e9471ec573ab2d44e7f462d996d614536e
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Wed, 6 Mar 2019 19:09:08 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 3 Apr 2019 09:39:46 +0200
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) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: andrew.cooper3@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/xen/hypercall.h | 24 ++++++++++++++++++++----
1 file changed, 20 insertions(+), 4 deletions(-)
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;
}
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