From: Alexey Dobriyan <adobriyan@gmail.com>
To: dhowells@redhat.com
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 34/45] C++: Fix up use of LIST_POISON*
Date: Mon, 2 Apr 2018 00:28:16 +0300 [thread overview]
Message-ID: <20180401212816.GA25507@avx2> (raw)
> - entry->next = LIST_POISON1;
> - entry->prev = LIST_POISON2;
> + entry->next = static_cast<struct list_head *>(LIST_POISON1);
> + entry->prev = static_cast<struct list_head *>(LIST_POISON2);
There is a better way ;-)
--- a/include/linux/poison.h
+++ b/include/linux/poison.h
@@ -2,6 +2,22 @@
#ifndef _LINUX_POISON_H
#define _LINUX_POISON_H
+class POISON {
+ unsigned long p;
+
+public:
+ explicit POISON(unsigned long val)
+ : p{val}
+ {
+ }
+
+ template<typename T>
+ operator T*() const
+ {
+ return p;
+ }
+};
+
/********** include/linux/list.h **********/
/*
@@ -20,15 +36,15 @@
* under normal circumstances, used to verify that nobody uses
* non-initialized list entries.
*/
-#define LIST_POISON1 ((void *) 0x100 + POISON_POINTER_DELTA)
-#define LIST_POISON2 ((void *) 0x200 + POISON_POINTER_DELTA)
+#define LIST_POISON1 POISON{0x100UL + POISON_POINTER_DELTA}
+#define LIST_POISON2 POISON{0x200UL + POISON_POINTER_DELTA}
/********** include/linux/timer.h **********/
/*
* Magic number "tsta" to indicate a static timer initializer
* for the object debugging code.
*/
-#define TIMER_ENTRY_STATIC ((void *) 0x300 + POISON_POINTER_DELTA)
+#define TIMER_ENTRY_STATIC POISON{0x300UL + POISON_POINTER_DELTA}
/********** mm/debug-pagealloc.c **********/
#ifdef CONFIG_PAGE_POISONING_ZERO
@@ -39,7 +55,7 @@
/********** mm/page_alloc.c ************/
-#define TAIL_MAPPING ((void *) 0x400 + POISON_POINTER_DELTA)
+#define TAIL_MAPPING POISON{0x400UL + POISON_POINTER_DELTA}
/********** mm/slab.c **********/
/*
@@ -81,7 +97,7 @@
/********** kernel/mutexes **********/
#define MUTEX_DEBUG_INIT 0x11
#define MUTEX_DEBUG_FREE 0x22
-#define MUTEX_POISON_WW_CTX ((void *) 0x500 + POISON_POINTER_DELTA)
+#define MUTEX_POISON_WW_CTX POISON{0x500UL + POISON_POINTER_DELTA}
/********** lib/flex_array.c **********/
#define FLEX_ARRAY_FREE 0x6c /* for use-after-free poisoning */
next reply other threads:[~2018-04-01 21:28 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-01 21:28 Alexey Dobriyan [this message]
-- strict thread matches above, loose matches on Subject: below --
2018-04-01 20:40 [PATCH 00/45] C++: Convert the kernel to C++ David Howells
2018-04-01 20:43 ` [PATCH 34/45] C++: Fix up use of LIST_POISON* David Howells
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