ARM_LPAE + VMSPLIT_2G cause swiotlb warning on Raspberry Pi 4
Florian Fainelli
f.fainelli at gmail.com
Tue May 16 15:17:59 PDT 2023
+Robin, Christoph,
Hi Stephan,
On 5/16/23 13:46, Stefan Wahren wrote:
> Hi,
> today i wanted to test the new arm/multi_v7_lpae_defconfig on my
> Raspberry Pi 4 8GB with Linux 6.4-rc2, but it fails everytime to boot
> properly from SD card:
>
> [ 0.000000] Booting Linux on physical CPU 0x0
> [ 0.000000] Linux version 6.4.0-rc2 (stefanw at stefanw-SCHENKER)
> (arm-linux-gnueabihf-gcc (GCC) 11.3.1 20220604 [releases/gcc-11 revision
> 591c0f4b92548e3ae2e8173f4f93984b1c7f62bb], GNU ld
> (Linaro_Binutils-2022.06) 2.37.20220122) #2 SMP Tue May 16 18:57:48 CEST
> 2023
> [ 0.000000] CPU: ARMv7 Processor [410fd083] revision 3 (ARMv7),
> cr=30c5383d
> [ 0.000000] CPU: div instructions available: patching division code
> [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction
> cache
> [ 0.000000] OF: fdt: Machine model: Raspberry Pi 4 Model B Rev 1.4
> [ 0.000000] random: crng init done
> [ 0.000000] Memory policy: Data cache writealloc
> [ 0.000000] efi: UEFI not found.
> [ 0.000000] Reserved memory: created CMA memory pool at
> 0x0000000037000000, size 64 MiB
> [ 0.000000] OF: reserved mem: initialized node linux,cma, compatible
> id shared-dma-pool
> [ 0.000000] OF: reserved mem: 0x0000000037000000..0x000000003affffff
> (65536 KiB) map reusable linux,cma
> [ 0.000000] OF: reserved mem: 0x000000003ef625a0..0x000000003ef62681
> (0 KiB) nomap non-reusable nvram at 0
> [ 0.000000] Zone ranges:
> [ 0.000000] DMA [mem 0x0000000000000000-0x000000003fffefff]
> [ 0.000000] Normal [mem 0x000000003ffff000-0x000000006fffffff]
> [ 0.000000] HighMem [mem 0x0000000070000000-0x00000001ffffffff]
> [ 0.000000] Movable zone start for each node
> [ 0.000000] Early memory node ranges
> [ 0.000000] node 0: [mem 0x0000000000000000-0x000000003b3fffff]
> [ 0.000000] node 0: [mem 0x0000000040000000-0x00000000fbffffff]
> [ 0.000000] node 0: [mem 0x0000000100000000-0x00000001ffffffff]
> [ 0.000000] Initmem setup node 0 [mem
> 0x0000000000000000-0x00000001ffffffff]
> [ 0.000000] On node 0, zone Normal: 1024 pages in unavailable ranges
> [ 0.000000] percpu: Embedded 16 pages/cpu s35988 r8192 d21356 u65536
> [ 0.000000] Kernel command line: dma.dmachans=0x37f5
> bcm2709.boardrev=0xd03114 bcm2709.serial=0x2e99bd7a
> bcm2709.uart_clock=48000000 bcm2709.disk_led_gpio=42
> bcm2709.disk_led_active_low=0 smsc95xx.macaddr=DC:A6:32:91:38:52
> vc_mem.mem_base=0x3ec00000 vc_mem.mem_size=0x40000000
> console=ttyS1,115200 console=tty1 root=PARTUUID=a5c5156c-02
> rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait
> plymouth.ignore-serial-consoles
>
> ...
>
> [ 1.422481] pcieport 0000:00:00.0: enabling device (0000 -> 0002)
> [ 1.422621] pcieport 0000:00:00.0: PME: Signaling with IRQ 35
> [ 1.434696] ------------[ cut here ]------------
> [ 1.434720] WARNING: CPU: 2 PID: 1 at kernel/dma/swiotlb.c:891
> swiotlb_map+0x328/0x330
> [ 1.434759] bcm2835-dma fe007000.dma: swiotlb addr
> 0xffffffffffffffff+4096 overflow (mask ffffffff, bus limit ffffffff).
> [ 1.434790] Modules linked in:
> [ 1.434813] CPU: 2 PID: 1 Comm: swapper/0 Not tainted 6.4.0-rc2 #2
> [ 1.434838] Hardware name: BCM2711
> [ 1.434862] unwind_backtrace from show_stack+0x10/0x14
> [ 1.434902] show_stack from dump_stack_lvl+0x40/0x4c
> [ 1.434938] dump_stack_lvl from __warn+0x7c/0x124
> [ 1.434980] __warn from warn_slowpath_fmt+0x118/0x174
> [ 1.435024] warn_slowpath_fmt from swiotlb_map+0x328/0x330
> [ 1.435062] swiotlb_map from dma_map_page_attrs+0x204/0x328
> [ 1.435100] dma_map_page_attrs from bcm2835_dma_probe+0x1d8/0x41c
> [ 1.435141] bcm2835_dma_probe from platform_probe+0x5c/0xbc
> [ 1.435174] platform_probe from really_probe+0xc8/0x2dc
> [ 1.435214] really_probe from __driver_probe_device+0x88/0x19c
> [ 1.435262] __driver_probe_device from driver_probe_device+0x30/0x104
> [ 1.435310] driver_probe_device from __driver_attach+0x90/0x174
> [ 1.435357] __driver_attach from bus_for_each_dev+0x6c/0xb4
> [ 1.435402] bus_for_each_dev from bus_add_driver+0xcc/0x1cc
> [ 1.435445] bus_add_driver from driver_register+0x7c/0x118
> [ 1.435479] driver_register from do_one_initcall+0x40/0x1e0
> [ 1.435509] do_one_initcall from kernel_init_freeable+0x1b8/0x220
> [ 1.435549] kernel_init_freeable from kernel_init+0x18/0x12c
> [ 1.435589] kernel_init from ret_from_fork+0x14/0x1c
> [ 1.435619] Exception stack(0xf081dfb0 to 0xf081dff8)
> [ 1.435641] dfa0: 00000000
> 00000000 00000000 00000000
> [ 1.435667] dfc0: 00000000 00000000 00000000 00000000 00000000
> 00000000 00000000 00000000
> [ 1.435692] dfe0: 00000000 00000000 00000000 00000000 00000013 00000000
> [ 1.435711] ---[ end trace 0000000000000000 ]---
> [ 1.435731] bcm2835-dma fe007000.dma: Failed to map zero page
> [ 1.435750] bcm2835-dma: probe of fe007000.dma failed with error -12
> [ 1.488044] Serial: 8250/16550 driver, 5 ports, IRQ sharing enabled
> [ 1.490574] printk: console [ttyS1] disabled
>
> So i went back to 6.3, 6.2, 6.1 & 5.15 (enabling the config options
> manually on top of multi_v7_defconfig), but it shows the same broken
> behavior.
>
> If i switch back to VMSPLIT_3G and keep ARM_LPAE, the system boots
> properly from SD card.
>
> Any ideas what's the issue here or how to investigate further?
The "brcm,bcm2835-dma" Device Tree node is located within the "soc" bus
node which has the following:
/* Emulate a contiguous 30-bit address range for DMA */
dma-ranges = <0xc0000000 0x0 0x00000000 0x40000000>;
which is necessary in order to use the non-allocating VPU L2 cache
aperture. Eventually we should trickle through translate_phys_to_dma and do:
>static inline dma_addr_t translate_phys_to_dma(struct device *dev,
>> phys_addr_t paddr)
{
const struct bus_dma_region *m;
for (m = dev->dma_range_map; m->size; m++)
if (paddr >= m->cpu_start && paddr - m->cpu_start <
m->size)
>> return (dma_addr_t)paddr - m->offset;
/* make sure dma_capable fails when no translation is
available */
>> return DMA_MAPPING_ERROR;
}
and I suspect that we did return DMA_MAPPING_ERROR (~0 =
0xffff_ffff_ffff_ffff) here which would suggest that somehow the
dma_range_map function pointer has not been set properly. Could you
instrument drivers/of/device.c and see whether that is, or is not the case?
Thanks!
--
Florian
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