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