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Set the malloc alignment to 64 bytes on platforms that use the U-Boot API

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device drivers.  Recent versions of u-boot run with the MMU enabled, and
require DMA-based I/O to be aligned to cache line boundaries.

These changes are based on a patch originally submitted by Juergen Weiss,
but I reworked them and thus any problems are purely my fault.

Submitted by:	"Juergen Weiss" <weiss@uni-mainz.de>
Reviewed by:	imp, nwhitehorn, jhb
This commit is contained in:
Ian Lepore 2014-02-05 22:53:58 +00:00
parent 3b78c64b35
commit b1526b43e8
4 changed files with 25 additions and 8 deletions
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6
lib/libstand/sbrk.c
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@ -33,6 +33,7 @@ __FBSDID("$FreeBSD$");
#include <string.h> #include <string.h>
#include "stand.h" #include "stand.h"
#include "zalloc_defs.h"
static size_t maxheap, heapsize = 0; static size_t maxheap, heapsize = 0;
static void *heapbase; static void *heapbase;
@ -40,8 +41,9 @@ static void *heapbase;
void void
setheap(void *base, void *top) setheap(void *base, void *top)
{ {
/* Align start address to 16 bytes for the malloc code. Sigh. */ /* Align start address for the malloc code. Sigh. */
heapbase = (void *)(((uintptr_t)base + 15) & ~15); heapbase = (void *)(((uintptr_t)base + MALLOCALIGN_MASK) &
~MALLOCALIGN_MASK);
maxheap = (char *)top - (char *)heapbase; maxheap = (char *)top - (char *)heapbase;
} }

9
lib/libstand/zalloc.c
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@ -70,6 +70,15 @@ __FBSDID("$FreeBSD$");
#include "zalloc_defs.h" #include "zalloc_defs.h"
/*
* Objects in the pool must be aligned to at least the size of struct MemNode.
* They must also be aligned to MALLOCALIGN, which should normally be larger
* than the struct, so assert that to be so at compile time.
*/
typedef char assert_align[(sizeof(struct MemNode) <= MALLOCALIGN) ? 1 : -1];
#define MEMNODE_SIZE_MASK MALLOCALIGN_MASK
/* /*
* znalloc() - allocate memory (without zeroing) from pool. Call reclaim * znalloc() - allocate memory (without zeroing) from pool. Call reclaim
* and retry if appropriate, return NULL if unable to allocate * and retry if appropriate, return NULL if unable to allocate

16
lib/libstand/zalloc_defs.h
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@ -52,18 +52,26 @@
#define BLKEXTENDMASK (BLKEXTEND - 1) #define BLKEXTENDMASK (BLKEXTEND - 1)
/* /*
* required malloc alignment. Just hardwire to 16. * Required malloc alignment.
* *
* Note: if we implement a more sophisticated realloc, we should ensure that * Embedded platforms using the u-boot API drivers require that all I/O buffers
* MALLOCALIGN is at least as large as MemNode. * be on a cache line sized boundary. The worst case size for that is 64 bytes.
* For other platforms, 16 bytes works fine. The alignment also must be at
* least sizeof(struct MemNode); this is asserted in zalloc.c.
*/ */
#if defined(__arm__) || defined(__mips__) || defined(__powerpc__)
#define MALLOCALIGN 64
#else
#define MALLOCALIGN 16
#endif
#define MALLOCALIGN_MASK (MALLOCALIGN - 1)
typedef struct Guard { typedef struct Guard {
size_t ga_Bytes; size_t ga_Bytes;
size_t ga_Magic; /* must be at least 32 bits */ size_t ga_Magic; /* must be at least 32 bits */
} Guard; } Guard;
#define MALLOCALIGN 16
#define GAMAGIC 0x55FF44FD #define GAMAGIC 0x55FF44FD
#define GAFREE 0x5F54F4DF #define GAFREE 0x5F54F4DF

2
lib/libstand/zalloc_mem.h
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@ -48,8 +48,6 @@ typedef struct MemPool {
uintptr_t mp_Used; uintptr_t mp_Used;
} MemPool; } MemPool;
#define MEMNODE_SIZE_MASK ((sizeof(MemNode) <= 8) ? 7 : 15)
#define ZNOTE_FREE 0 #define ZNOTE_FREE 0
#define ZNOTE_REUSE 1 #define ZNOTE_REUSE 1