[PATCH v2 for-4.10] ubsan: add clang 5.0 support

* [PATCH v2 for-4.10] ubsan: add clang 5.0 support
@ 2017-10-18  7:45 Roger Pau Monne
  2017-10-18  9:23 ` Jan Beulich
                   ` (2 more replies)
  0 siblings, 3 replies; 7+ messages in thread
From: Roger Pau Monne @ 2017-10-18  7:45 UTC (permalink / raw)
  To: xen-devel
  Cc: Stefano Stabellini, Wei Liu, Konrad Rzeszutek Wilk,
	George Dunlap, Andrew Cooper, Ian Jackson, Tim Deegan,
	Julien Grall, Jan Beulich, Roger Pau Monne

clang 5.0 changed the layout of the type_mismatch_data structure and
introduced __ubsan_handle_type_mismatch_v1 and
__ubsan_handle_pointer_overflow.

This commit adds support for the new structure layout, adds the
missing handlers and the new types for type_check_kinds.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: George Dunlap <George.Dunlap@eu.citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Tim Deegan <tim@xen.org>
Cc: Wei Liu <wei.liu2@citrix.com>
Cc: Julien Grall <julien.grall@arm.com>
---
ubsan is an optional feature, not enabled by default and not designed
to be used by production systems. Since this change only touches ubsan
code and it's a bugfix in order for clang to work, I argue it should
be merged into 4.10.
---
Changes since v1:
 - Replace message in __ubsan_handle_pointer_overflow.
 - Add a suppress_report check in __ubsan_handle_type_mismatch_v1.
---
 xen/common/ubsan/ubsan.c | 46 +++++++++++++++++++++++++++++++++++++++++++++-
 xen/common/ubsan/ubsan.h | 11 +++++++++++
 2 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/xen/common/ubsan/ubsan.c b/xen/common/ubsan/ubsan.c
index fbe568562a..2eaa403691 100644
--- a/xen/common/ubsan/ubsan.c
+++ b/xen/common/ubsan/ubsan.c
@@ -33,7 +33,10 @@ const char *type_check_kinds[] = {
 	"member call on",
 	"constructor call on",
 	"downcast of",
-	"downcast of"
+	"downcast of",
+	"upcast of",
+	"cast to virtual base of",
+	"_Nonnull binding to",
 };
 
 #define REPORTED_BIT 31
@@ -333,6 +336,26 @@ void __ubsan_handle_type_mismatch(struct type_mismatch_data *data,
 }
 EXPORT_SYMBOL(__ubsan_handle_type_mismatch);
 
+void __ubsan_handle_type_mismatch_v1(struct type_mismatch_data_v1 *data,
+				unsigned long ptr)
+{
+	struct type_mismatch_data d = {
+		.location = data->location,
+		.type = data->type,
+		.alignment = 1ul << data->log_alignment,
+		.type_check_kind = data->type_check_kind,
+	};
+
+	/*
+	 * NB: do the check with data->location, d->location is just a local
+	 * copy and the modifications will be lost.
+	 */
+	if (suppress_report(&data->location))
+		return;
+
+	__ubsan_handle_type_mismatch(&d, ptr);
+}
+
 void __ubsan_handle_nonnull_arg(struct nonnull_arg_data *data)
 {
 	unsigned long flags;
@@ -478,3 +501,24 @@ void __ubsan_handle_load_invalid_value(struct invalid_value_data *data,
 	ubsan_epilogue(&flags);
 }
 EXPORT_SYMBOL(__ubsan_handle_load_invalid_value);
+
+void __ubsan_handle_pointer_overflow(struct pointer_overflow_data *data,
+				unsigned long base, unsigned long result)
+{
+	unsigned long flags;
+
+	if (suppress_report(&data->location))
+		return;
+
+	ubsan_prologue(&data->location, &flags);
+
+	if (((long)base >= 0) == ((long)result >= 0))
+		pr_err("pointer operation %s %p to %p\n",
+			base > result ? "underflowed" : "overflowed",
+			(void *)base, (void *)result);
+	else
+		pr_err("pointer index expression with base %p overflowed to %p\n",
+			(void *)base, (void *)result);
+
+	ubsan_epilogue(&flags);
+}
diff --git a/xen/common/ubsan/ubsan.h b/xen/common/ubsan/ubsan.h
index b2d18d4a53..2710cd423e 100644
--- a/xen/common/ubsan/ubsan.h
+++ b/xen/common/ubsan/ubsan.h
@@ -36,6 +36,13 @@ struct type_mismatch_data {
 	unsigned char type_check_kind;
 };
 
+struct type_mismatch_data_v1 {
+	struct source_location location;
+	struct type_descriptor *type;
+	unsigned char log_alignment;
+	unsigned char type_check_kind;
+};
+
 struct nonnull_arg_data {
 	struct source_location location;
 	struct source_location attr_location;
@@ -73,6 +80,10 @@ struct invalid_value_data {
 	struct type_descriptor *type;
 };
 
+struct pointer_overflow_data {
+	struct source_location location;
+};
+
 #if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
 typedef __int128 s_max;
 typedef unsigned __int128 u_max;
-- 
2.13.5 (Apple Git-94)


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