[Xen-devel] [PATCH v3 17/17] livepatch: Add xen_local_symbols test-case

[Konrad Rzeszutek Wilk <konrad@xxxxxxxxxx>]

To exercise the local/global visibility.

With "livepatch: Add local and global symbol resolution."
we can load both xen_hello_world and xen_local_symbols
without having to worry about:

-bash-4.1# xen-livepatch load xen_hello_world.livepatch
Uploading xen_hello_world.livepatch... completed
Applying xen_hello_world... completed
-bash-4.1# xen-livepatch list
 ID                                     | status
----------------------------------------+------------
xen_hello_world                         | APPLIED
-bash-4.1# xen-livepatch upload xen_local_symbols xen_local_symbols.livepatch
Uploading xen_local_symbols.livepatch... failed
(XEN) livepatch.c:819: livepatch: xen_local_symbols: duplicate new symbol: 
revert_hook

In fact you will see:

livepatch: xen_hello_world: new local symbol revert_hook
livepatch: xen_hello_world: new local symbol apply_hook
livepatch: xen_hello_world: new local symbol check_fnc
livepatch: xen_hello_world: new local symbol hello_world_patch_this_fnc

...
livepatch: xen_local_symbols: new local symbol revert_hook
livepatch: xen_local_symbols: new local symbol apply_hook
livepatch: xen_local_symbols: new local symbol hello_world_patch_this_fnc
..

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
v1: First edition
v2: Build with mkhex version of build-id from hypervisor.
---
 xen/test/livepatch/Makefile            | 12 +++++++-
 xen/test/livepatch/xen_local_symbols.c | 53 ++++++++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+), 1 deletion(-)
 create mode 100644 xen/test/livepatch/xen_local_symbols.c

diff --git a/xen/test/livepatch/Makefile b/xen/test/livepatch/Makefile
index 6e5b9a3a75..f88c8f9c80 100644
--- a/xen/test/livepatch/Makefile
+++ b/xen/test/livepatch/Makefile
@@ -11,11 +11,13 @@ LIVEPATCH := xen_hello_world.livepatch
 LIVEPATCH_BYE := xen_bye_world.livepatch
 LIVEPATCH_REPLACE := xen_replace_world.livepatch
 LIVEPATCH_NOP := xen_nop.livepatch
+LIVEPATCH_LOCAL := xen_local_symbols.livepatch
 
 LIVEPATCHES += $(LIVEPATCH)
 LIVEPATCHES += $(LIVEPATCH_BYE)
 LIVEPATCHES += $(LIVEPATCH_REPLACE)
 LIVEPATCHES += $(LIVEPATCH_NOP)
+LIVEPATCHES += $(LIVEPATCH_LOCAL)
 
 LIVEPATCH_DEBUG_DIR ?= $(DEBUG_DIR)/xen-livepatch
 
@@ -109,5 +111,13 @@ $(LIVEPATCH_NOP): xen_nop.o
        $(OBJCOPY) --strip-debug --strip-symbol=$(NOTE_SYMBOL) $@
        $(OBJCOPY) --set-section-flags .livepatch.funcs=alloc,readonly $@
 
+xen_local_symbols.o: config.h livepatch_depends.h
+
+.PHONY: $(LIVEPATCH_LOCAL)
+$(LIVEPATCH_LOCAL): xen_hello_world_func.o xen_local_symbols.o
+       $(LD) $(LDFLAGS) $(build_id_linker) -r -o $(LIVEPATCH_LOCAL) $^
+       $(OBJCOPY) --strip-debug --strip-symbol=$(NOTE_SYMBOL) $@
+       $(OBJCOPY) --set-section-flags .livepatch.funcs=alloc,readonly $@
+
 .PHONY: livepatch
-livepatch: $(LIVEPATCH) $(LIVEPATCH_BYE) $(LIVEPATCH_REPLACE) $(LIVEPATCH_NOP)
+livepatch: $(LIVEPATCH) $(LIVEPATCH_BYE) $(LIVEPATCH_REPLACE) $(LIVEPATCH_NOP) 
$(LIVEPATCH_LOCAL)
diff --git a/xen/test/livepatch/xen_local_symbols.c 
b/xen/test/livepatch/xen_local_symbols.c
new file mode 100644
index 0000000000..448c489818
--- /dev/null
+++ b/xen/test/livepatch/xen_local_symbols.c
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2017 Oracle and/or its affiliates. All rights reserved.
+ */
+
+#include "config.h"
+#include <xen/lib.h>
+#include <xen/types.h>
+#include <xen/version.h>
+#include <xen/livepatch.h>
+#include <xen/livepatch_payload.h>
+
+#include <public/sysctl.h>
+#include "livepatch_depends.h"
+
+/* Same name as in xen_hello_world */
+static const char hello_world_patch_this_fnc[] = "xen_extra_version";
+extern const char *xen_hello_world(void);
+
+/*
+ * The hooks are static here (LOCAL) and also in xen_hello_world.c
+ * and their name is exactly the same.
+ */
+static void apply_hook(void)
+{
+    printk(KERN_DEBUG "local_symbols: Hook executing.\n");
+}
+
+static void revert_hook(void)
+{
+    printk(KERN_DEBUG "local_symbols: Hook unloaded.\n");
+}
+
+LIVEPATCH_LOAD_HOOK(apply_hook);
+LIVEPATCH_UNLOAD_HOOK(revert_hook);
+
+struct livepatch_func __section(".livepatch.funcs") 
livepatch_xen_local_symbols = {
+    .version = LIVEPATCH_PAYLOAD_VERSION,
+    .name = hello_world_patch_this_fnc,
+    .new_addr = xen_hello_world,
+    .old_addr = xen_extra_version,
+    .new_size = NEW_CODE_SZ,
+    .old_size = OLD_CODE_SZ,
+};
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
-- 
2.13.3


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