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[Xen-changelog] [xen master] xen/ubsan: Import ubsan implementation from Linux 4.13



commit 00fcf4dd8eb403a7de5210a457c60cd339ed36c1
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Tue Oct 3 19:07:51 2017 +0100
Commit:     Wei Liu <wei.liu2@xxxxxxxxxx>
CommitDate: Mon Oct 9 17:04:55 2017 +0100

    xen/ubsan: Import ubsan implementation from Linux 4.13
    
    A future change will adjust it to compile in Xen.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
    Reviewed-by: Wei Liu <wei.liu2@xxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/common/ubsan/Makefile |   1 +
 xen/common/ubsan/ubsan.c  | 456 ++++++++++++++++++++++++++++++++++++++++++++++
 xen/common/ubsan/ubsan.h  |  84 +++++++++
 3 files changed, 541 insertions(+)

diff --git a/xen/common/ubsan/Makefile b/xen/common/ubsan/Makefile
new file mode 100644
index 0000000..e6b85ea
--- /dev/null
+++ b/xen/common/ubsan/Makefile
@@ -0,0 +1 @@
+obj-y += ubsan.o
diff --git a/xen/common/ubsan/ubsan.c b/xen/common/ubsan/ubsan.c
new file mode 100644
index 0000000..fb0409d
--- /dev/null
+++ b/xen/common/ubsan/ubsan.c
@@ -0,0 +1,456 @@
+/*
+ * UBSAN error reporting functions
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ * Author: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#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 "ubsan.h"
+
+const char *type_check_kinds[] = {
+       "load of",
+       "store to",
+       "reference binding to",
+       "member access within",
+       "member call on",
+       "constructor call on",
+       "downcast of",
+       "downcast of"
+};
+
+#define REPORTED_BIT 31
+
+#if (BITS_PER_LONG == 64) && defined(__BIG_ENDIAN)
+#define COLUMN_MASK (~(1U << REPORTED_BIT))
+#define LINE_MASK   (~0U)
+#else
+#define COLUMN_MASK   (~0U)
+#define LINE_MASK (~(1U << REPORTED_BIT))
+#endif
+
+#define VALUE_LENGTH 40
+
+static bool was_reported(struct source_location *location)
+{
+       return test_and_set_bit(REPORTED_BIT, &location->reported);
+}
+
+static void print_source_location(const char *prefix,
+                               struct source_location *loc)
+{
+       pr_err("%s %s:%d:%d\n", prefix, loc->file_name,
+               loc->line & LINE_MASK, loc->column & COLUMN_MASK);
+}
+
+static bool suppress_report(struct source_location *loc)
+{
+       return current->in_ubsan || was_reported(loc);
+}
+
+static bool type_is_int(struct type_descriptor *type)
+{
+       return type->type_kind == type_kind_int;
+}
+
+static bool type_is_signed(struct type_descriptor *type)
+{
+       WARN_ON(!type_is_int(type));
+       return  type->type_info & 1;
+}
+
+static unsigned type_bit_width(struct type_descriptor *type)
+{
+       return 1 << (type->type_info >> 1);
+}
+
+static bool is_inline_int(struct type_descriptor *type)
+{
+       unsigned inline_bits = sizeof(unsigned long)*8;
+       unsigned bits = type_bit_width(type);
+
+       WARN_ON(!type_is_int(type));
+
+       return bits <= inline_bits;
+}
+
+static s_max get_signed_val(struct type_descriptor *type, unsigned long val)
+{
+       if (is_inline_int(type)) {
+               unsigned extra_bits = sizeof(s_max)*8 - type_bit_width(type);
+               return ((s_max)val) << extra_bits >> extra_bits;
+       }
+
+       if (type_bit_width(type) == 64)
+               return *(s64 *)val;
+
+       return *(s_max *)val;
+}
+
+static bool val_is_negative(struct type_descriptor *type, unsigned long val)
+{
+       return type_is_signed(type) && get_signed_val(type, val) < 0;
+}
+
+static u_max get_unsigned_val(struct type_descriptor *type, unsigned long val)
+{
+       if (is_inline_int(type))
+               return val;
+
+       if (type_bit_width(type) == 64)
+               return *(u64 *)val;
+
+       return *(u_max *)val;
+}
+
+static void val_to_string(char *str, size_t size, struct type_descriptor *type,
+       unsigned long value)
+{
+       if (type_is_int(type)) {
+               if (type_bit_width(type) == 128) {
+#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
+                       u_max val = get_unsigned_val(type, value);
+
+                       scnprintf(str, size, "0x%08x%08x%08x%08x",
+                               (u32)(val >> 96),
+                               (u32)(val >> 64),
+                               (u32)(val >> 32),
+                               (u32)(val));
+#else
+                       WARN_ON(1);
+#endif
+               } else if (type_is_signed(type)) {
+                       scnprintf(str, size, "%lld",
+                               (s64)get_signed_val(type, value));
+               } else {
+                       scnprintf(str, size, "%llu",
+                               (u64)get_unsigned_val(type, value));
+               }
+       }
+}
+
+static bool location_is_valid(struct source_location *loc)
+{
+       return loc->file_name != NULL;
+}
+
+static DEFINE_SPINLOCK(report_lock);
+
+static void ubsan_prologue(struct source_location *location,
+                       unsigned long *flags)
+{
+       current->in_ubsan++;
+       spin_lock_irqsave(&report_lock, *flags);
+
+       pr_err("========================================"
+               "========================================\n");
+       print_source_location("UBSAN: Undefined behaviour in", location);
+}
+
+static void ubsan_epilogue(unsigned long *flags)
+{
+       dump_stack();
+       pr_err("========================================"
+               "========================================\n");
+       spin_unlock_irqrestore(&report_lock, *flags);
+       current->in_ubsan--;
+}
+
+static void handle_overflow(struct overflow_data *data, unsigned long lhs,
+                       unsigned long rhs, char op)
+{
+
+       struct type_descriptor *type = data->type;
+       unsigned long flags;
+       char lhs_val_str[VALUE_LENGTH];
+       char rhs_val_str[VALUE_LENGTH];
+
+       if (suppress_report(&data->location))
+               return;
+
+       ubsan_prologue(&data->location, &flags);
+
+       val_to_string(lhs_val_str, sizeof(lhs_val_str), type, lhs);
+       val_to_string(rhs_val_str, sizeof(rhs_val_str), type, rhs);
+       pr_err("%s integer overflow:\n",
+               type_is_signed(type) ? "signed" : "unsigned");
+       pr_err("%s %c %s cannot be represented in type %s\n",
+               lhs_val_str,
+               op,
+               rhs_val_str,
+               type->type_name);
+
+       ubsan_epilogue(&flags);
+}
+
+void __ubsan_handle_add_overflow(struct overflow_data *data,
+                               unsigned long lhs,
+                               unsigned long rhs)
+{
+
+       handle_overflow(data, lhs, rhs, '+');
+}
+EXPORT_SYMBOL(__ubsan_handle_add_overflow);
+
+void __ubsan_handle_sub_overflow(struct overflow_data *data,
+                               unsigned long lhs,
+                               unsigned long rhs)
+{
+       handle_overflow(data, lhs, rhs, '-');
+}
+EXPORT_SYMBOL(__ubsan_handle_sub_overflow);
+
+void __ubsan_handle_mul_overflow(struct overflow_data *data,
+                               unsigned long lhs,
+                               unsigned long rhs)
+{
+       handle_overflow(data, lhs, rhs, '*');
+}
+EXPORT_SYMBOL(__ubsan_handle_mul_overflow);
+
+void __ubsan_handle_negate_overflow(struct overflow_data *data,
+                               unsigned long old_val)
+{
+       unsigned long flags;
+       char old_val_str[VALUE_LENGTH];
+
+       if (suppress_report(&data->location))
+               return;
+
+       ubsan_prologue(&data->location, &flags);
+
+       val_to_string(old_val_str, sizeof(old_val_str), data->type, old_val);
+
+       pr_err("negation of %s cannot be represented in type %s:\n",
+               old_val_str, data->type->type_name);
+
+       ubsan_epilogue(&flags);
+}
+EXPORT_SYMBOL(__ubsan_handle_negate_overflow);
+
+
+void __ubsan_handle_divrem_overflow(struct overflow_data *data,
+                               unsigned long lhs,
+                               unsigned long rhs)
+{
+       unsigned long flags;
+       char rhs_val_str[VALUE_LENGTH];
+
+       if (suppress_report(&data->location))
+               return;
+
+       ubsan_prologue(&data->location, &flags);
+
+       val_to_string(rhs_val_str, sizeof(rhs_val_str), data->type, rhs);
+
+       if (type_is_signed(data->type) && get_signed_val(data->type, rhs) == -1)
+               pr_err("division of %s by -1 cannot be represented in type 
%s\n",
+                       rhs_val_str, data->type->type_name);
+       else
+               pr_err("division by zero\n");
+
+       ubsan_epilogue(&flags);
+}
+EXPORT_SYMBOL(__ubsan_handle_divrem_overflow);
+
+static void handle_null_ptr_deref(struct type_mismatch_data *data)
+{
+       unsigned long flags;
+
+       if (suppress_report(&data->location))
+               return;
+
+       ubsan_prologue(&data->location, &flags);
+
+       pr_err("%s null pointer of type %s\n",
+               type_check_kinds[data->type_check_kind],
+               data->type->type_name);
+
+       ubsan_epilogue(&flags);
+}
+
+static void handle_missaligned_access(struct type_mismatch_data *data,
+                               unsigned long ptr)
+{
+       unsigned long flags;
+
+       if (suppress_report(&data->location))
+               return;
+
+       ubsan_prologue(&data->location, &flags);
+
+       pr_err("%s misaligned address %p for type %s\n",
+               type_check_kinds[data->type_check_kind],
+               (void *)ptr, data->type->type_name);
+       pr_err("which requires %ld byte alignment\n", data->alignment);
+
+       ubsan_epilogue(&flags);
+}
+
+static void handle_object_size_mismatch(struct type_mismatch_data *data,
+                                       unsigned long ptr)
+{
+       unsigned long flags;
+
+       if (suppress_report(&data->location))
+               return;
+
+       ubsan_prologue(&data->location, &flags);
+       pr_err("%s address %p with insufficient space\n",
+               type_check_kinds[data->type_check_kind],
+               (void *) ptr);
+       pr_err("for an object of type %s\n", data->type->type_name);
+       ubsan_epilogue(&flags);
+}
+
+void __ubsan_handle_type_mismatch(struct type_mismatch_data *data,
+                               unsigned long ptr)
+{
+
+       if (!ptr)
+               handle_null_ptr_deref(data);
+       else if (data->alignment && !IS_ALIGNED(ptr, data->alignment))
+               handle_missaligned_access(data, ptr);
+       else
+               handle_object_size_mismatch(data, ptr);
+}
+EXPORT_SYMBOL(__ubsan_handle_type_mismatch);
+
+void __ubsan_handle_nonnull_return(struct nonnull_return_data *data)
+{
+       unsigned long flags;
+
+       if (suppress_report(&data->location))
+               return;
+
+       ubsan_prologue(&data->location, &flags);
+
+       pr_err("null pointer returned from function declared to never return 
null\n");
+
+       if (location_is_valid(&data->attr_location))
+               print_source_location("returns_nonnull attribute specified in",
+                               &data->attr_location);
+
+       ubsan_epilogue(&flags);
+}
+EXPORT_SYMBOL(__ubsan_handle_nonnull_return);
+
+void __ubsan_handle_vla_bound_not_positive(struct vla_bound_data *data,
+                                       unsigned long bound)
+{
+       unsigned long flags;
+       char bound_str[VALUE_LENGTH];
+
+       if (suppress_report(&data->location))
+               return;
+
+       ubsan_prologue(&data->location, &flags);
+
+       val_to_string(bound_str, sizeof(bound_str), data->type, bound);
+       pr_err("variable length array bound value %s <= 0\n", bound_str);
+
+       ubsan_epilogue(&flags);
+}
+EXPORT_SYMBOL(__ubsan_handle_vla_bound_not_positive);
+
+void __ubsan_handle_out_of_bounds(struct out_of_bounds_data *data,
+                               unsigned long index)
+{
+       unsigned long flags;
+       char index_str[VALUE_LENGTH];
+
+       if (suppress_report(&data->location))
+               return;
+
+       ubsan_prologue(&data->location, &flags);
+
+       val_to_string(index_str, sizeof(index_str), data->index_type, index);
+       pr_err("index %s is out of range for type %s\n", index_str,
+               data->array_type->type_name);
+       ubsan_epilogue(&flags);
+}
+EXPORT_SYMBOL(__ubsan_handle_out_of_bounds);
+
+void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data,
+                                       unsigned long lhs, unsigned long rhs)
+{
+       unsigned long flags;
+       struct type_descriptor *rhs_type = data->rhs_type;
+       struct type_descriptor *lhs_type = data->lhs_type;
+       char rhs_str[VALUE_LENGTH];
+       char lhs_str[VALUE_LENGTH];
+
+       if (suppress_report(&data->location))
+               return;
+
+       ubsan_prologue(&data->location, &flags);
+
+       val_to_string(rhs_str, sizeof(rhs_str), rhs_type, rhs);
+       val_to_string(lhs_str, sizeof(lhs_str), lhs_type, lhs);
+
+       if (val_is_negative(rhs_type, rhs))
+               pr_err("shift exponent %s is negative\n", rhs_str);
+
+       else if (get_unsigned_val(rhs_type, rhs) >=
+               type_bit_width(lhs_type))
+               pr_err("shift exponent %s is too large for %u-bit type %s\n",
+                       rhs_str,
+                       type_bit_width(lhs_type),
+                       lhs_type->type_name);
+       else if (val_is_negative(lhs_type, lhs))
+               pr_err("left shift of negative value %s\n",
+                       lhs_str);
+       else
+               pr_err("left shift of %s by %s places cannot be"
+                       " represented in type %s\n",
+                       lhs_str, rhs_str,
+                       lhs_type->type_name);
+
+       ubsan_epilogue(&flags);
+}
+EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds);
+
+
+void __noreturn
+__ubsan_handle_builtin_unreachable(struct unreachable_data *data)
+{
+       unsigned long flags;
+
+       ubsan_prologue(&data->location, &flags);
+       pr_err("calling __builtin_unreachable()\n");
+       ubsan_epilogue(&flags);
+       panic("can't return from __builtin_unreachable()");
+}
+EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable);
+
+void __ubsan_handle_load_invalid_value(struct invalid_value_data *data,
+                               unsigned long val)
+{
+       unsigned long flags;
+       char val_str[VALUE_LENGTH];
+
+       if (suppress_report(&data->location))
+               return;
+
+       ubsan_prologue(&data->location, &flags);
+
+       val_to_string(val_str, sizeof(val_str), data->type, val);
+
+       pr_err("load of value %s is not a valid value for type %s\n",
+               val_str, data->type->type_name);
+
+       ubsan_epilogue(&flags);
+}
+EXPORT_SYMBOL(__ubsan_handle_load_invalid_value);
diff --git a/xen/common/ubsan/ubsan.h b/xen/common/ubsan/ubsan.h
new file mode 100644
index 0000000..b2d18d4
--- /dev/null
+++ b/xen/common/ubsan/ubsan.h
@@ -0,0 +1,84 @@
+#ifndef _LIB_UBSAN_H
+#define _LIB_UBSAN_H
+
+enum {
+       type_kind_int = 0,
+       type_kind_float = 1,
+       type_unknown = 0xffff
+};
+
+struct type_descriptor {
+       u16 type_kind;
+       u16 type_info;
+       char type_name[1];
+};
+
+struct source_location {
+       const char *file_name;
+       union {
+               unsigned long reported;
+               struct {
+                       u32 line;
+                       u32 column;
+               };
+       };
+};
+
+struct overflow_data {
+       struct source_location location;
+       struct type_descriptor *type;
+};
+
+struct type_mismatch_data {
+       struct source_location location;
+       struct type_descriptor *type;
+       unsigned long alignment;
+       unsigned char type_check_kind;
+};
+
+struct nonnull_arg_data {
+       struct source_location location;
+       struct source_location attr_location;
+       int arg_index;
+};
+
+struct nonnull_return_data {
+       struct source_location location;
+       struct source_location attr_location;
+};
+
+struct vla_bound_data {
+       struct source_location location;
+       struct type_descriptor *type;
+};
+
+struct out_of_bounds_data {
+       struct source_location location;
+       struct type_descriptor *array_type;
+       struct type_descriptor *index_type;
+};
+
+struct shift_out_of_bounds_data {
+       struct source_location location;
+       struct type_descriptor *lhs_type;
+       struct type_descriptor *rhs_type;
+};
+
+struct unreachable_data {
+       struct source_location location;
+};
+
+struct invalid_value_data {
+       struct source_location location;
+       struct type_descriptor *type;
+};
+
+#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
+typedef __int128 s_max;
+typedef unsigned __int128 u_max;
+#else
+typedef s64 s_max;
+typedef u64 u_max;
+#endif
+
+#endif
--
generated by git-patchbot for /home/xen/git/xen.git#master

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