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fs/shm: alloc aligned memory if CPU has cache 

For kernel builds, shared memory is automatically aligned to page size.
For flat and protected builds, we align the memory size to the CPU cache
line size.

Failure to align memory properly could result in partial data read/write
by the CPU and peripherals, potentially causing data corruption during
cache flushes or invalidations.

Signed-off-by: xuxingliang <xuxingliang@xiaomi.com>
This commit is contained in:
xuxingliang 2024-10-16 10:19:30 +08:00 committed by Xiang Xiao
parent 22bcb88687
commit 9af5fc5d09
1 changed files with 28 additions and 13 deletions
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39
fs/shm/shmfs_alloc.c
View File

@ -27,6 +27,7 @@
#include <stdbool.h>
#include <nuttx/arch.h>
#include <nuttx/cache.h>
#include <nuttx/kmalloc.h>
#include <nuttx/pgalloc.h>
@ -47,20 +48,24 @@ FAR struct shmfs_object_s *shmfs_alloc_object(size_t length)
* chunk in kernel heap
*/
size_t alloc_size = sizeof(struct shmfs_object_s) + length;
if (alloc_size < length)
{
/* There must have been an integer overflow */
return NULL;
}
object = fs_heap_zalloc(alloc_size);
object = fs_heap_zalloc(sizeof(struct shmfs_object_s));
if (object)
{
object->paddr = (FAR char *)(object + 1);
size_t cachesize = up_get_dcache_linesize();
if (cachesize > 0)
{
object->paddr = fs_heap_memalign(cachesize, length);
}
else
{
object->paddr = fs_heap_malloc(length);
}
if (object->paddr)
{
allocated = true;
}
}
#elif defined(CONFIG_BUILD_PROTECTED)
/* in PROTECTED build, allocate the shm object in kernel heap, and shared
@ -70,7 +75,15 @@ FAR struct shmfs_object_s *shmfs_alloc_object(size_t length)
object = fs_heap_zalloc(sizeof(struct shmfs_object_s));
if (object)
{
object->paddr = kumm_zalloc(length);
size_t cachesize = up_get_dcache_linesize();
if (cachesize > 0)
{
object->paddr = kumm_memalign(cachesize, length);
}
else
{
object->paddr = kumm_malloc(length);
}
if (object->paddr)
{
@ -140,7 +153,9 @@ void shmfs_free_object(FAR struct shmfs_object_s *object)
if (object)
{
#if defined (CONFIG_BUILD_PROTECTED)
#if defined(CONFIG_BUILD_FLAT)
fs_heap_free(object->paddr);
#elif defined(CONFIG_BUILD_PROTECTED)
kumm_free(object->paddr);
#elif defined(CONFIG_BUILD_KERNEL)
pages = &object->paddr;