From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Date: Wed, 2 Aug 2017 00:29:01 +0000 (+0000)
Subject: livepatch: Expand check for safe_for_reapply if livepatch has only .rodata.
X-Git-Tag: archive/raspbian/4.11.1-1+rpi1~1^2~66^2~1228
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=66d3f83db68a529fee807151d9b2906851f58cac;p=xen.git

livepatch: Expand check for safe_for_reapply if livepatch has only .rodata.

If the livepatch has only .rodata sections then it is OK to also
apply/revert/apply the livepatch without having to worry about the
unforseen consequences.

See commit 98b728a7b235c67e210f67f789db5d9eb38ca00c
"livepatch: Disallow applying after an revert" for details.

Reviewed-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---

diff --git a/xen/common/livepatch.c b/xen/common/livepatch.c
index 039382934d..b9376c94e9 100644
--- a/xen/common/livepatch.c
+++ b/xen/common/livepatch.c
@@ -417,9 +417,12 @@ static int move_payload(struct payload *payload, struct livepatch_elf *elf)
         }
     }
 
-    /* Only one RW section with non-zero size: .livepatch.funcs */
-    if ( rw_buf_cnt == 1 &&
-         !strcmp(elf->sec[rw_buf_sec].name, ELF_LIVEPATCH_FUNC) )
+    /*
+     * Only one RW section with non-zero size: .livepatch.funcs,
+     * or only RO sections.
+     */
+    if ( !rw_buf_cnt || (rw_buf_cnt == 1 &&
+         !strcmp(elf->sec[rw_buf_sec].name, ELF_LIVEPATCH_FUNC)) )
         payload->safe_to_reapply = true;
  out:
     xfree(offset);