[PATCH 1/6] malloc: define a maximum malloc size

[Ahmad Fatoum]

TLSF and dlmalloc each already enforce a maximum allocation size.

Let's define SZ_1G as common maximum allocation size in preparation
for aligning all allocators to observe it.

The intention is to make code easier to reason about and as extra
hardening against possible, yet undiscovered, allocator bugs.

Suggested-by: Richard Weinberger <richard at nod.at>
Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 include/malloc.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/malloc.h b/include/malloc.h
index 7bee03dab236..c38726342c08 100644
--- a/include/malloc.h
+++ b/include/malloc.h
@@ -5,6 +5,9 @@
 #include <linux/compiler.h>
 #include <types.h>
 
+#define MALLOC_SHIFT_MAX	30
+#define MALLOC_MAX_SIZE		(1UL << MALLOC_SHIFT_MAX)
+
 #if IN_PROPER
 void *malloc(size_t) __alloc_size(1);
 size_t malloc_usable_size(void *);
-- 
2.39.5