The patch titled
Subject: drivers: dma-coherent: use memset_io for DMA_MEMORY_IO mappings
has been added to the -mm tree. Its filename is
drivers-dma-coherent-use-memset_io-for-dma_memory_io-mappings.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/drivers-dma-coherent-use-memset_io-for-dma_memory_io-mappings.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/drivers-dma-coherent-use-memset_io-for-dma_memory_io-mappings.patch
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------------------------------------------------------
From: Brian Starkey <brian.starkey@xxxxxxx>
Subject: drivers: dma-coherent: use memset_io for DMA_MEMORY_IO mappings
Use memset_io() for DMA_MEMORY_IO mappings which are mapped as I/O memory,
and regular memset() for DMA_MEMORY_MAP mappings.
This fixes the below alignment fault on arm64 for DMA_MEMORY_IO mappings,
where memset() uses the DC ZVA instruction which is invalid on device
memory.
Unhandled fault: alignment fault (0x96000061) at 0xffffff8000380000
Internal error: : 96000061 [#1] PREEMPT SMP
Modules linked in: hdlcd(+) clk_scpi
CPU: 4 PID: 1355 Comm: systemd-udevd Not tainted 4.4.0-rc1+ #5
Hardware name: ARM Juno development board (r0) (DT)
task: ffffffc9763eee00 ti: ffffffc9758c4000 task.ti: ffffffc9758c4000
PC is at __efistub_memset+0x1ac/0x200
LR is at dma_alloc_from_coherent+0xb0/0x120
pc : [<ffffffc00030ff2c>] lr : [<ffffffc00042a918>] pstate: 400001c5
sp : ffffffc9758c79a0
x29: ffffffc9758c79a0 x28: ffffffc000635cd0
x27: 0000000000000124 x26: ffffffc000119ef4
x25: 0000000000010000 x24: 0000000000000140
x23: ffffffc07e9ac3a8 x22: ffffffc9758c7a58
x21: ffffffc9758c7a68 x20: 0000000000000004
x19: ffffffc07e9ac380 x18: 0000000000000001
x17: 0000007fae1bbba8 x16: ffffffc0001b2d1c
x15: ffffffffffffffff x14: 0ffffffffffffffe
x13: 0000000000000010 x12: ffffff800837ffff
x11: ffffff800837ffff x10: 0000000040000000
x9 : 0000000000000000 x8 : ffffff8000380000
x7 : 0000000000000000 x6 : 000000000000003f
x5 : 0000000000000040 x4 : 0000000000000000
x3 : 0000000000000004 x2 : 000000000000ffc0
x1 : 0000000000000000 x0 : ffffff8000380000
Signed-off-by: Brian Starkey <brian.starkey@xxxxxxx>
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/base/dma-coherent.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff -puN drivers/base/dma-coherent.c~drivers-dma-coherent-use-memset_io-for-dma_memory_io-mappings drivers/base/dma-coherent.c
--- a/drivers/base/dma-coherent.c~drivers-dma-coherent-use-memset_io-for-dma_memory_io-mappings
+++ a/drivers/base/dma-coherent.c
@@ -187,7 +187,10 @@ int dma_alloc_from_coherent(struct devic
*/
*dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
*ret = mem->virt_base + (pageno << PAGE_SHIFT);
- memset(*ret, 0, size);
+ if (mem->flags & DMA_MEMORY_MAP)
+ memset(*ret, 0, size);
+ else
+ memset_io(*ret, 0, size);
spin_unlock_irqrestore(&mem->spinlock, flags);
return 1;
_
Patches currently in -mm which might be from brian.starkey@xxxxxxx are
memremap-dont-modify-flags.patch
memremap-add-memremap_wc-flag.patch
drivers-dma-coherent-use-memremap_wc-for-dma_memory_map.patch
drivers-dma-coherent-use-memset_io-for-dma_memory_io-mappings.patch
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