On 06.11.18 11:54:15, Robin Murphy wrote:
> of_dma_configure() was *supposed* to be following the same logic as
> acpi_dma_configure() and only setting bus_dma_mask if some range was
> specified by the firmware. However, it seems that subtlety got lost in
> the process of fitting it into the differently-shaped control flow, and
> as a result the force_dma==true case ends up always setting the bus mask
> to the 32-bit default, which is not what anyone wants.
>
> Make sure we only touch it if the DT actually said so.
>
> Fixes: 6c2fb2ea7636 ("of/device: Set bus DMA mask as appropriate")
> Reported-by: Aaro Koskinen <aaro.koskinen@xxxxxx>
> Reported-by: Jean-Philippe Brucker <jean-philippe.brucker@xxxxxxx>
> Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
Tested-by: Robert Richter <robert.richter@xxxxxxxxxx>
This patch makes the bad page state message on Cavium ThunderX below
disappear.
Note: The Fixes: tag suggests the issue was already in 4.19, but I
have seen it in 4.20-rc1 first and it was pulled into mainline with:
cff229491af5 Merge tag 'dma-mapping-4.20' of git://git.infradead.org/users/hch/dma-mapping
-Robert
[ 37.634555] BUG: Bad page state in process swapper/5 pfn:f3ebb
[ 37.640483] page:ffff7e0003cfaec0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
[ 37.648493] flags: 0xffff00000001000(reserved)
[ 37.652942] raw: 0ffff00000001000 ffff7e0003cfaec8 ffff7e0003cfaec8 0000000000000000
[ 37.660691] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
[ 37.668438] page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
[ 37.674880] bad because of flags: 0x1000(reserved)
[ 37.679672] Modules linked in: ip6t_REJECT nf_reject_ipv6 xt_tcpudp ipt_REJECT nf_reject_ipv4 xt_conntrack ip6table_nat nf_nat_ipv6 ip6table_mangle iptable_nat nf_nat_ipv4 nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_mangle ip6table_filter ip6_tables iptable_filter crct10dif_ce cavium_rng_vf rng_core ipmi_ssif thunderx_zip thunderx_edac ipmi_devintf cavium_rng ipmi_msghandler ip_tables x_tables xfs libcrc32c nicvf nicpf thunder_bgx thunder_xcv i2c_thunderx mdio_thunder mdio_cavium ipv6
[ 37.723866] CPU: 5 PID: 0 Comm: swapper/5 Not tainted 4.20.0-rc1-00012-gc106b1cbe843 #1
[ 37.731874] Hardware name: Cavium ThunderX CRB/To be filled by O.E.M., BIOS 5.11 12/12/2012
[ 37.740228] Call trace:
[ 37.742677] dump_backtrace+0x0/0x148
[ 37.746334] show_stack+0x14/0x1c
[ 37.749643] dump_stack+0x84/0xa8
[ 37.752954] bad_page+0xe4/0x144
[ 37.756178] free_pages_check_bad+0x7c/0x84
[ 37.760355] __free_pages_ok+0x22c/0x284
[ 37.764272] page_frag_free+0x64/0x68
[ 37.767930] skb_free_head+0x24/0x2c
[ 37.771500] skb_release_data+0x130/0x148
[ 37.775504] skb_release_all+0x24/0x30
[ 37.779246] kfree_skb+0x2c/0x54
[ 37.782471] ip_error+0x70/0x1d4
[ 37.785693] ip_rcv_finish+0x3c/0x50
[ 37.789262] ip_rcv+0xc0/0xd0
[ 37.792225] __netif_receive_skb_one_core+0x4c/0x70
[ 37.797099] __netif_receive_skb+0x2c/0x70
[ 37.801190] netif_receive_skb_internal+0x64/0x160
[ 37.805976] napi_gro_receive+0xa0/0xc4
[ 37.809815] nicvf_cq_intr_handler+0x930/0xc1c [nicvf]
[ 37.814950] nicvf_poll+0x30/0xb0 [nicvf]
[ 37.818954] net_rx_action+0x140/0x2f8
[ 37.822697] __do_softirq+0x11c/0x228
[ 37.826354] irq_exit+0xbc/0xd0
[ 37.829491] __handle_domain_irq+0x6c/0xb4
[ 37.833581] gic_handle_irq+0x8c/0x1a0
[ 37.837324] el1_irq+0xb0/0x128
[ 37.840459] arch_cpu_idle+0x10/0x18
[ 37.844031] default_idle_call+0x18/0x28
[ 37.847948] do_idle+0x194/0x258
[ 37.851169] cpu_startup_entry+0x20/0x24
[ 37.855089] secondary_start_kernel+0x144/0x168
> ---
>
> Sorry about that... I guess I only have test setups that either have
> dma-ranges or where a 32-bit bus mask goes unnoticed :(
>
> The Octeon and SMMU issues sound like they're purely down to this, and
> it's probably related to at least one of John's Hikey woes.
>
> Robin.
>
> drivers/of/device.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/of/device.c b/drivers/of/device.c
> index 0f27fad9fe94..757ae867674f 100644
> --- a/drivers/of/device.c
> +++ b/drivers/of/device.c
> @@ -149,7 +149,8 @@ int of_dma_configure(struct device *dev, struct device_node *np, bool force_dma)
> * set by the driver.
> */
> mask = DMA_BIT_MASK(ilog2(dma_addr + size - 1) + 1);
> - dev->bus_dma_mask = mask;
> + if (!ret)
> + dev->bus_dma_mask = mask;
> dev->coherent_dma_mask &= mask;
> *dev->dma_mask &= mask;
>
> --
> 2.19.1.dirty
>
>
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