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Merge pull request #15056 from maribu/gnrc_pktbuf_static_alignment

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sys/net/gnrc/pktbuf_static: Fix alignment
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Martine Lenders 2020-09-22 17:07:07 +02:00 committed by GitHub
commit 5e4c285323
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1 changed files with 11 additions and 5 deletions
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16
sys/net/gnrc/pktbuf_static/gnrc_pktbuf_static.c
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@ -41,7 +41,11 @@ typedef struct _unused {
} _unused_t; } _unused_t;
static mutex_t _mutex = MUTEX_INIT; static mutex_t _mutex = MUTEX_INIT;
static uint8_t _pktbuf[CONFIG_GNRC_PKTBUF_SIZE]; /* The static buffer needs to be aligned to word size, so that its start
* address can be casted to `_unused_t *` safely. Just allocating an array of
* (word sized) uintptr_t is a trivial way to do this */
static uintptr_t _pktbuf_buf[CONFIG_GNRC_PKTBUF_SIZE / sizeof(uintptr_t)];
static uint8_t *_pktbuf = (uint8_t *)_pktbuf_buf;
static _unused_t *_first_unused; static _unused_t *_first_unused;
#ifdef DEVELHELP #ifdef DEVELHELP
@ -82,9 +86,9 @@ static inline void _set_pktsnip(gnrc_pktsnip_t *pkt, gnrc_pktsnip_t *next,
void gnrc_pktbuf_init(void) void gnrc_pktbuf_init(void)
{ {
mutex_lock(&_mutex); mutex_lock(&_mutex);
_first_unused = (_unused_t *)_pktbuf; _first_unused = (_unused_t *)_pktbuf_buf;
_first_unused->next = NULL; _first_unused->next = NULL;
_first_unused->size = sizeof(_pktbuf); _first_unused->size = sizeof(_pktbuf_buf);
mutex_unlock(&_mutex); mutex_unlock(&_mutex);
} }
@ -341,7 +345,7 @@ void gnrc_pktbuf_stats(void)
bool gnrc_pktbuf_is_empty(void) bool gnrc_pktbuf_is_empty(void)
{ {
return (_first_unused == (_unused_t *)_pktbuf) && return (_first_unused == (_unused_t *)_pktbuf) &&
(_first_unused->size == sizeof(_pktbuf)); (_first_unused->size == sizeof(_pktbuf_buf));
} }
bool gnrc_pktbuf_is_sane(void) bool gnrc_pktbuf_is_sane(void)
@ -424,7 +428,9 @@ static void *_pktbuf_alloc(size_t size)
} }
} }
else { else {
_unused_t *new = (_unused_t *)(((uint8_t *)ptr) + size); /* alignment is ensured by rounding size up in the _align() function.
* We cast to uintptr_t as intermediate step to silence -Wcast-align */
_unused_t *new = (_unused_t *)((uintptr_t)ptr + size);
if (((((uint8_t *)new) - &(_pktbuf[0])) + sizeof(_unused_t)) > CONFIG_GNRC_PKTBUF_SIZE) { if (((((uint8_t *)new) - &(_pktbuf[0])) + sizeof(_unused_t)) > CONFIG_GNRC_PKTBUF_SIZE) {
/* content of new would exceed packet buffer size so set to NULL */ /* content of new would exceed packet buffer size so set to NULL */