[PATCH] iommu/mediatek: Limit the physical address in 32bit for v7s

[Yong Wu]

The ARM short descriptor has already limited the physical address
to 32bit after the commit <76557391433c> ("iommu/io-pgtable: Sanitise
map/unmap addresses"). But in MediaTek 4GB mode, the physical address
is from 0x1_0000_0000 to 0x1_ffff_ffff. this will cause:

WARNING: CPU: 4 PID: 3900 at
xxx/drivers/iommu/io-pgtable-arm-v7s.c:482 arm_v7s_map+0x40/0xf8
Modules linked in:

CPU: 4 PID: 3900 Comm: weston Tainted: G S      W       4.9.44 #1
Hardware name: MediaTek MT2712m1v1 board (DT)
task: ffffffc0eaa5b280 task.stack: ffffffc0e9858000
PC is at arm_v7s_map+0x40/0xf8
LR is at mtk_iommu_map+0x64/0x90
pc : [<ffffff80085b09e8>] lr : [<ffffff80085b29fc>] pstate: 000001c5
sp : ffffffc0e985b920
x29: ffffffc0e985b920 x28: 0000000127d00000
x27: 0000000000100000 x26: ffffff8008f9e000
x25: 0000000000000003 x24: 0000000000100000
x23: 0000000127d00000 x22: 00000000ff800000
x21: ffffffc0f7ec8ce0 x20: 0000000000000003
x19: 0000000000000003 x18: 0000000000000002
x17: 0000007f7e5d72c0 x16: ffffff80082b0f08
x15: 0000000000000001 x14: 000000000000003f
x13: 0000000000000000 x12: 0000000000000028
x11: 0088000000000000 x10: 0000000000000000
x9 : ffffff80092fa000 x8 : ffffffc0e9858000
x7 : ffffff80085b29d8 x6 : 0000000000000000
x5 : ffffff80085b09a8 x4 : 0000000000000003
x3 : 0000000000100000 x2 : 0000000127d00000
x1 : 00000000ff800000 x0 : 0000000000000001
...
Call trace:
[<ffffff80085b09e8>] arm_v7s_map+0x40/0xf8
[<ffffff80085b29fc>] mtk_iommu_map+0x64/0x90
[<ffffff80085ab5f8>] iommu_map+0x100/0x3a0
[<ffffff80085ab99c>] default_iommu_map_sg+0x104/0x168
[<ffffff80085aead8>] iommu_dma_alloc+0x238/0x3f8
[<ffffff8008098b30>] __iommu_alloc_attrs+0xa8/0x260
[<ffffff80085f364c>] mtk_drm_gem_create+0xac/0x180
[<ffffff80085f3894>] mtk_drm_gem_dumb_create+0x54/0xc8
[<ffffff80085d576c>] drm_mode_create_dumb_ioctl+0xa4/0xd8
[<ffffff80085cb2a0>] drm_ioctl+0x1c0/0x490

In order to satify this, Limit the physical address to 32bit.

Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
---
Base on v4.14-rc1.
---
 drivers/iommu/mtk_iommu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index bd515be..16d33ac 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -371,7 +371,8 @@ static int mtk_iommu_map(struct iommu_domain *domain, unsigned long iova,
 	int ret;
 
 	spin_lock_irqsave(&dom->pgtlock, flags);
-	ret = dom->iop->map(dom->iop, iova, paddr, size, prot);
+	ret = dom->iop->map(dom->iop, iova, paddr & DMA_BIT_MASK(32),
+			    size, prot);
 	spin_unlock_irqrestore(&dom->pgtlock, flags);
 
 	return ret;
-- 
1.8.1.1.dirty