From: Florian Fainelli f.fainelli@gmail.com
[ Upstream commit fb0fd3469ead5b937293c213daa1f589b4b7ce46 ]
Commit 26f09e9b3a06 ("mm/memblock: add memblock memory allocation apis") added a check to determine whether arm_dma_zone_size is exceeding the amount of kernel virtual address space available between the upper 4GB virtual address limit and PAGE_OFFSET in order to provide a suitable definition of MAX_DMA_ADDRESS that should fit within the 32-bit virtual address space. The quantity used for comparison was off by a missing trailing 0, leading to MAX_DMA_ADDRESS to be overflowing a 32-bit quantity.
This was caught thanks to CONFIG_DEBUG_VIRTUAL on the bcm2711 platform where we define a dma_zone_size of 1GB and we have a PAGE_OFFSET value of 0xc000_0000 (CONFIG_VMSPLIT_3G) leading to MAX_DMA_ADDRESS being 0x1_0000_0000 which overflows the unsigned long type used throughout __pa() and then __virt_addr_valid(). Because the virtual address passed to __virt_addr_valid() would now be 0, the function would loudly warn and flood the kernel log, thus making the platform unable to boot properly.
Fixes: 26f09e9b3a06 ("mm/memblock: add memblock memory allocation apis") Signed-off-by: Florian Fainelli f.fainelli@gmail.com Reviewed-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Russell King (Oracle) rmk+kernel@armlinux.org.uk Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm/include/asm/dma.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/include/asm/dma.h b/arch/arm/include/asm/dma.h index a81dda65c576..45180a2cc47c 100644 --- a/arch/arm/include/asm/dma.h +++ b/arch/arm/include/asm/dma.h @@ -10,7 +10,7 @@ #else #define MAX_DMA_ADDRESS ({ \ extern phys_addr_t arm_dma_zone_size; \ - arm_dma_zone_size && arm_dma_zone_size < (0x10000000 - PAGE_OFFSET) ? \ + arm_dma_zone_size && arm_dma_zone_size < (0x100000000ULL - PAGE_OFFSET) ? \ (PAGE_OFFSET + arm_dma_zone_size) : 0xffffffffUL; }) #endif