From 20d7a35bc8be06dd1350de0454b0e24cca1d4354 Mon Sep 17 00:00:00 2001 From: Brian Starkey Date: Tue, 22 Mar 2016 14:28:06 -0700 Subject: [PATCH] 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 : [] lr : [] 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 Reviewed-by: Catalin Marinas Cc: Dan Williams Cc: Greg Kroah-Hartman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/base/dma-coherent.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c index 25bb398ec7a1..bdf28f7dd5e8 100644 --- a/drivers/base/dma-coherent.c +++ b/drivers/base/dma-coherent.c @@ -187,7 +187,10 @@ int dma_alloc_from_coherent(struct device *dev, ssize_t size, */ *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; -- GitLab