[v4,7/8] xen: add /buildinfo/config entry to hypervisor filesystem

Commit Message

Jürgen Groß Feb. 5, 2020, 10:11 a.m. UTC

Add the /buildinfo/config entry to the hypervisor filesystem. This
entry contains the .config file used to build the hypervisor.

Signed-off-by: Juergen Gross <[e-mail]>
---
V3:
- store data in gzip format
- use binfile mechanism to create data file
- move code to kernel.c
---
 .gitignore                   |  2 ++
 docs/misc/hypfs-paths.pandoc |  4 ++++
 xen/common/Makefile          | 12 ++++++++++++
 xen/common/kernel.c          | 10 ++++++++++
 xen/include/xen/kernel.h     |  3 +++
 5 files changed, 31 insertions(+)

Patch

diff --git a/.gitignore b/.gitignore
index fd5610718d..bc8e053ccb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -297,6 +297,8 @@  xen/arch/*/efi/boot.c
 xen/arch/*/efi/compat.c
 xen/arch/*/efi/efi.h
 xen/arch/*/efi/runtime.c
+xen/common/config_data.S
+xen/common/config.gz
 xen/include/headers*.chk
 xen/include/asm
 xen/include/asm-*/asm-offsets.h
diff --git a/docs/misc/hypfs-paths.pandoc b/docs/misc/hypfs-paths.pandoc
index e392feff27..1faebcccbc 100644
--- a/docs/misc/hypfs-paths.pandoc
+++ b/docs/misc/hypfs-paths.pandoc
@@ -133,6 +133,10 @@  Information about the compile domain.
 
 The compiler used to build Xen.
 
+#### /buildinfo/config = STRING
+
+The contents of the `xen/.config` file at the time of the hypervisor build.
+
 #### /buildinfo/version/
 
 A directory containing version information of the hypervisor.
diff --git a/xen/common/Makefile b/xen/common/Makefile
index 3a2c1ae690..72fb790c57 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -1,6 +1,7 @@ 
 obj-$(CONFIG_ARGO) += argo.o
 obj-y += bitmap.o
 obj-y += bsearch.o
+obj-y += config_data.o
 obj-$(CONFIG_CORE_PARKING) += core_parking.o
 obj-y += cpu.o
 obj-$(CONFIG_DEBUG_TRACE) += debugtrace.o
@@ -73,3 +74,14 @@  subdir-$(CONFIG_UBSAN) += ubsan
 
 subdir-$(CONFIG_NEEDS_LIBELF) += libelf
 subdir-$(CONFIG_HAS_DEVICE_TREE) += libfdt
+
+config.gz: ../.config
+	gzip -c $< >$@
+
+config_data.o: config.gz
+
+config_data.S: $(XEN_ROOT)/xen/tools/binfile
+	$(XEN_ROOT)/xen/tools/binfile $@ config.gz xen_config_data
+
+clean::
+	rm config_data.S config.gz 2>/dev/null || true
diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index 6ee0e64404..3d496bb9e6 100644
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -388,6 +388,13 @@  static HYPFS_STRING_INIT(compile_by, "compile_by");
 static HYPFS_STRING_INIT(compile_date, "compile_date");
 static HYPFS_STRING_INIT(compile_domain, "compile_domain");
 static HYPFS_STRING_INIT(extra, "extra");
+static struct hypfs_entry_leaf config = {
+    .e.type = XEN_HYPFS_TYPE_STRING,
+    .e.encoding = XEN_HYPFS_ENC_GZIP,
+    .e.name = "config",
+    .e.read = hypfs_read_leaf,
+    .content = &xen_config_data
+};
 
 static int __init buildinfo_init(void)
 {
@@ -414,6 +421,9 @@  static int __init buildinfo_init(void)
     hypfs_add_leaf(&version, &major, true);
     hypfs_add_leaf(&version, &minor, true);
 
+    config.e.size = xen_config_data_size;
+    hypfs_add_leaf(&buildinfo, &config, true);
+
     return 0;
 }
 __initcall(buildinfo_init);
diff --git a/xen/include/xen/kernel.h b/xen/include/xen/kernel.h
index 548b64da9f..2f883031f9 100644
--- a/xen/include/xen/kernel.h
+++ b/xen/include/xen/kernel.h
@@ -100,5 +100,8 @@  extern enum system_state {
 
 bool_t is_active_kernel_text(unsigned long addr);
 
+extern char xen_config_data;
+extern unsigned int xen_config_data_size;
+
 #endif /* _LINUX_KERNEL_H */