[PATCH 4.14 008/159] x86/xen: Add unwind hint annotations

Greg Kroah-Hartman
2017-12-22T09:58:50Z

From: Josh Poimboeuf <jpoimboe@redhat.com>

commit abbe1cac6214d81d2f4e149aba64a8760703144e upstream.

Add unwind hint annotations to the xen head code so the ORC unwinder can
read head_64.o.

hypercall_page needs empty annotations at 32-byte intervals to match the
'xen_hypercall_*' ELF functions at those locations.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/70ed2eb516fe9266be766d953f93c2571bca88cc.1505764066.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/xen/xen-head.S | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

--- a/arch/x86/xen/xen-head.S
+++ b/arch/x86/xen/xen-head.S
@@ -10,6 +10,7 @@
#include <asm/boot.h>
#include <asm/asm.h>
#include <asm/page_types.h>
+#include <asm/unwind_hints.h>

#include <xen/interface/elfnote.h>
#include <xen/interface/features.h>
@@ -20,6 +21,7 @@
#ifdef CONFIG_XEN_PV
__INIT
ENTRY(startup_xen)
+ UNWIND_HINT_EMPTY
cld

/* Clear .bss */
@@ -41,7 +43,10 @@ END(startup_xen)
.pushsection .text
.balign PAGE_SIZE
ENTRY(hypercall_page)
- .skip PAGE_SIZE
+ .rept (PAGE_SIZE / 32)
+ UNWIND_HINT_EMPTY
+ .skip 32
+ .endr

#define HYPERCALL(n) \
.equ xen_hypercall_##n, hypercall_page + __HYPERVISOR_##n * 32; \