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63 lines
2.4 KiB
Diff
63 lines
2.4 KiB
Diff
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From d9527989b2d63749d6c6678fa3a1b658eb26c225 Mon Sep 17 00:00:00 2001
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From: Mathias Kresin <dev@kresin.me>
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Date: Tue, 2 Nov 2021 21:24:29 +0100
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Subject: [PATCH] dma: lantiq: fix out of bounds cache invalidate
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With gcc10 the variables are placed more tightly to each other, which
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uncovers a long existing bug in the lantiq DMA code. It can be observed
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when using tftpboot with the filename parameter, which gets reset during
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the tftpboot execution.
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NetRxPackets[] points to cache line size aligned addresses. In
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ltq_eth_rx_packet_align() the address NetRxPackets[] points to is
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increased by LTQ_ETH_IP_ALIGN and the resulting not cache aligned
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address is used further on. While doing so, the length/size is never
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updated.
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The "not cache aligned address" + len/size for a cache aligned address
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is passed to invalidate_dcache_range(). Hence, invalidate_dcache_range()
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invalidates the next 32 bit as well, which flashes the BootFile variable
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as well.
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variable BootFile is at address: 0x83ffe12c
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NetRxPackets[] points to 0x83ffdb20 (len is 0x600)
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data points to: 0x83ffdb22 (len is 0x600)
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ltq_dma_dcache_inv: 0x83ffdb22 (for len 0x600)
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invalidate_dcache_range: 0x83ffdb20 to 0x83ffe120 (size: 32)
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invalidate_dcache_range: 0x83ffdb20 to 0x83ffdb40 (Bootfile: a.bin)
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...
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invalidate_dcache_range: 0x83ffe100 to 0x83ffe120 (Bootfile: a.bin)
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invalidate_dcache_range: 0x83ffe120 to 0x83ffe140 (Bootfile: )
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In ltq_dma_tx_map() and ltq_dma_rx_map() the start address passed to
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ltq_dma_dcache_wb_inv() is incorrect. By considering the offset, the
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start address passed to flush_dcache_range() is always aligned to 32, 64
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or 128 bytes dependent on configured DMA burst size.
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Signed-off-by: Mathias Kresin <dev@kresin.me>
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---
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drivers/dma/lantiq_dma.c | 4 ++--
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1 file changed, 2 insertions(+), 2 deletions(-)
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--- a/drivers/dma/lantiq_dma.c
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+++ b/drivers/dma/lantiq_dma.c
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@@ -280,7 +280,7 @@ int ltq_dma_rx_map(struct ltq_dma_device
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offset = dma_addr % ltq_dma_burst_align(dev->rx_burst_len);
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- ltq_dma_dcache_inv(data, len);
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+ ltq_dma_dcache_inv(data - offset, len);
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#if 0
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printf("%s: index %d, data %p, dma_addr %08x, offset %u, len %d\n",
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@@ -355,7 +355,7 @@ int ltq_dma_tx_map(struct ltq_dma_device
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__func__, index, desc, data, dma_addr, offset, len);
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#endif
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- ltq_dma_dcache_wb_inv(data, len);
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+ ltq_dma_dcache_wb_inv(data - offset, len);
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desc->addr = dma_addr - offset;
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desc->ctl = DMA_DESC_OWN | DMA_DESC_SOP | DMA_DESC_EOP |
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