[Xen-changelog] [xen master] xen: hook up UBSAN with CONFIG_UBSAN

[patchbot@xxxxxxx]

commit 572a78190403e5f2acbd01fa72c35fafe9700169
Author:     Wei Liu <wei.liu2@xxxxxxxxxx>
AuthorDate: Mon Oct 9 14:54:58 2017 +0100
Commit:     Wei Liu <wei.liu2@xxxxxxxxxx>
CommitDate: Mon Oct 9 17:05:00 2017 +0100

    xen: hook up UBSAN with CONFIG_UBSAN
    
    Make the following changes:
    
    1. Introduce CONFIG_UBSAN and other auxiliary options.
    2. Introduce Build system rune to filter objects.
    3. Make ubsan.c build.
    
    Currently only x86 is supported. All init.o's are filtered out because
    of limitation in the build system. There is no user of noubsan-y yet
    but it is worth keeping to ease future development.
    
    Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/Kconfig              |  6 ++++++
 xen/Kconfig.debug        | 10 ++++++++++
 xen/Rules.mk             |  4 ++++
 xen/arch/x86/Kconfig     |  2 ++
 xen/common/Kconfig       |  3 +++
 xen/common/Makefile      |  1 +
 xen/common/ubsan/ubsan.c | 19 ++++++++++++-------
 7 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/xen/Kconfig b/xen/Kconfig
index 65d491d..ea7229a 100644
--- a/xen/Kconfig
+++ b/xen/Kconfig
@@ -38,4 +38,10 @@ config LTO
 
          If unsure, say N.
 
+#
+# For architectures that know their compiler __int128 support is sound
+#
+config ARCH_SUPPORTS_INT128
+       bool
+
 source "Kconfig.debug"
diff --git a/xen/Kconfig.debug b/xen/Kconfig.debug
index 195d504..3329c75 100644
--- a/xen/Kconfig.debug
+++ b/xen/Kconfig.debug
@@ -121,6 +121,16 @@ config SCRUB_DEBUG
          Verify that pages that need to be scrubbed before being allocated to
          a guest are indeed scrubbed.
 
+config UBSAN
+       bool "Undefined behaviour sanitizer"
+       depends on HAS_UBSAN
+       ---help---
+         Enable undefined behaviour sanitizer. It uses compiler to insert code
+         snippets so that undefined behaviours in C are detected during 
runtime.
+         This requires a UBSAN capable compiler and it is a debug only feature.
+
+         If unsure, say N here.
+
 endif # DEBUG || EXPERT
 
 endmenu
diff --git a/xen/Rules.mk b/xen/Rules.mk
index cafc67b..2659f8a 100644
--- a/xen/Rules.mk
+++ b/xen/Rules.mk
@@ -119,6 +119,10 @@ ifeq ($(CONFIG_GCOV),y)
 $(filter-out %.init.o $(nogcov-y),$(obj-y) $(obj-bin-y) $(extra-y)): CFLAGS += 
-fprofile-arcs -ftest-coverage
 endif
 
+ifeq ($(CONFIG_UBSAN),y)
+$(filter-out %.init.o $(noubsan-y),$(obj-y) $(obj-bin-y) $(extra-y)): CFLAGS 
+= -fsanitize=undefined
+endif
+
 ifeq ($(CONFIG_LTO),y)
 CFLAGS += -flto
 LDFLAGS-$(clang) += -plugin LLVMgold.so
diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
index 30c2769..64955dc 100644
--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -5,6 +5,7 @@ config X86
        def_bool y
        select ACPI
        select ACPI_LEGACY_TABLES_LOOKUP
+       select ARCH_SUPPORTS_INT128
        select COMPAT
        select CORE_PARKING
        select HAS_ALTERNATIVE
@@ -21,6 +22,7 @@ config X86
        select HAS_PASSTHROUGH
        select HAS_PCI
        select HAS_PDX
+       select HAS_UBSAN
        select NUMA
        select VGA
 
diff --git a/xen/common/Kconfig b/xen/common/Kconfig
index e9bb849..103ef44 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -32,6 +32,9 @@ config HAS_MEM_SHARING
 config HAS_PDX
        bool
 
+config HAS_UBSAN
+       bool
+
 config HAS_KEXEC
        bool
 
diff --git a/xen/common/Makefile b/xen/common/Makefile
index 39e2614..66cc2c8 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -75,6 +75,7 @@ tmem-$(CONFIG_COMPAT) += compat/tmem_xen.o
 obj-$(CONFIG_TMEM) += $(tmem-y)
 
 subdir-$(CONFIG_GCOV) += gcov
+subdir-$(CONFIG_UBSAN) += ubsan
 
 subdir-y += libelf
 subdir-$(CONFIG_HAS_DEVICE_TREE) += libfdt
diff --git a/xen/common/ubsan/ubsan.c b/xen/common/ubsan/ubsan.c
index 685b4de..fbe5685 100644
--- a/xen/common/ubsan/ubsan.c
+++ b/xen/common/ubsan/ubsan.c
@@ -10,13 +10,18 @@
  *
  */
 
-#include <linux/bitops.h>
-#include <linux/bug.h>
-#include <linux/ctype.h>
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/types.h>
-#include <linux/sched.h>
+#include <xen/spinlock.h>
+#include <xen/percpu.h>
+
+#define __noreturn    noreturn
+#define pr_err(...) printk(XENLOG_ERR __VA_ARGS__)
+struct xen_ubsan { int in_ubsan; };
+static DEFINE_PER_CPU(struct xen_ubsan[1], in_ubsan);
+#undef current
+#define current this_cpu(in_ubsan)
+#define dump_stack dump_execution_state
+#define u64 long long unsigned int
+#define s64 long long int
 
 #include "ubsan.h"
 
--
generated by git-patchbot for /home/xen/git/xen.git#master

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