Messages in this thread Patch in this message | | | From | Florian Fainelli <> | Subject | [PATCH 2/2] ARM: Clamp MAX_DMA_ADDRESS to 32-bit | Date | Thu, 24 Mar 2022 10:54:17 -0700 |
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MAX_DMA_ADDRESS is a virtual address, therefore it needs to fit within a 32-bit unsigned quantity. Platforms defining a DMA zone size in their machine descriptor can easily overflow this quantity depending on the DMA zone size and/or the PAGE_OFFSET setting.
In most cases this is harmless, however in the case of a CONFIG_DEBUG_VIRTUAL enabled, __virt_addr_valid() will be unable to return that MAX_DMA_ADDRESS is valid because the value passed to that function is an unsigned long which has already overflowed.
Fixes: e377cd8221eb ("ARM: 8640/1: Add support for CONFIG_DEBUG_VIRTUAL") Fixes: 2fb3ec5c9503 ("ARM: Replace platform definition of ISA_DMA_THRESHOLD/MAX_DMA_ADDRESS") Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> --- arch/arm/include/asm/dma.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/arm/include/asm/dma.h b/arch/arm/include/asm/dma.h index f244ee68e814..ea47420babd4 100644 --- a/arch/arm/include/asm/dma.h +++ b/arch/arm/include/asm/dma.h @@ -8,10 +8,12 @@ #ifndef CONFIG_ZONE_DMA #define MAX_DMA_ADDRESS 0xffffffffUL #else +#include <linux/minmax.h> #define MAX_DMA_ADDRESS ({ \ extern phys_addr_t arm_dma_zone_size; \ arm_dma_zone_size && arm_dma_zone_size < (0x10000000 - PAGE_OFFSET) ? \ - (PAGE_OFFSET + arm_dma_zone_size - 1) : 0xffffffffUL; }) + min_t(phys_addr_t, (PAGE_OFFSET + arm_dma_zone_size - 1), 0xffffffffUL) : \ + 0xffffffffUL; }) #endif #ifdef CONFIG_ISA_DMA_API -- 2.25.1
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