| Message ID | 1535106615-24282-1-git-send-email-yamada.masahiro@socionext.com |
|---|---|
| State | Accepted |
| Commit | e3332e1a1a04534225801c2710c6faef4809641c |
| Headers | show |
| Series | Make kmalloc'ed memory really DMA-safe | expand |
On Fri, Aug 24, 2018 at 07:30:15PM +0900, Masahiro Yamada wrote: > In Linux, the memory returned by kmalloc() is DMA-capable. > However, it is not true in U-Boot. > > At a glance, kmalloc() in U-Boot returns address aligned with > ARCH_DMA_MINALIGN. However, it never pads the allocated memory. > This half-way house is completely useless because calling kmalloc() > and malloc() in this order causes a cache sharing problem. > > Change the implementation to call malloc_cache_aligned(), which > allocates really DMA-capable memory. > > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Applied to u-boot/master, thanks! -- Tom
diff --git a/lib/linux_compat.c b/lib/linux_compat.c index a936a7e..6373b44 100644 --- a/lib/linux_compat.c +++ b/lib/linux_compat.c @@ -1,5 +1,6 @@ #include <common.h> +#include <memalign.h> #include <linux/compat.h> struct p_current cur = { @@ -18,7 +19,7 @@ void *kmalloc(size_t size, int flags) { void *p; - p = memalign(ARCH_DMA_MINALIGN, size); + p = malloc_cache_aligned(size); if (flags & __GFP_ZERO) memset(p, 0, size); @@ -37,5 +38,5 @@ struct kmem_cache *get_mem(int element_sz) void *kmem_cache_alloc(struct kmem_cache *obj, int flag) { - return memalign(ARCH_DMA_MINALIGN, obj->sz); + return malloc_cache_aligned(obj->sz); }
In Linux, the memory returned by kmalloc() is DMA-capable. However, it is not true in U-Boot. At a glance, kmalloc() in U-Boot returns address aligned with ARCH_DMA_MINALIGN. However, it never pads the allocated memory. This half-way house is completely useless because calling kmalloc() and malloc() in this order causes a cache sharing problem. Change the implementation to call malloc_cache_aligned(), which allocates really DMA-capable memory. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> --- lib/linux_compat.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)