Date:   Mon, 15 Nov 2021 13:53:24 +0200
From:   Ilias Apalodimas <ilias.apalodimas@linaro.org>
To:     Yunsheng Lin <linyunsheng@huawei.com>
Cc:     Guillaume Tucker <guillaume.tucker@collabora.com>,
        davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, linuxarm@openeuler.org,
        hawk@kernel.org, akpm@linux-foundation.org, peterz@infradead.org,
        will@kernel.org, jhubbard@nvidia.com, yuzhao@google.com,
        mcroce@microsoft.com, fenghua.yu@intel.com, feng.tang@intel.com,
        jgg@ziepe.ca, aarcange@redhat.com, guro@fb.com,
        "kernelci@groups.io" <kernelci@groups.io>
Subject: Re: [PATCH net-next v6] page_pool: disable dma mapping support for
 32-bit arch with 64-bit DMA
Message-ID: <YZJKNLEm6YTkygHM@apalos.home>
References: <20211013091920.1106-1-linyunsheng@huawei.com>
 <b9c0e7ef-a7a2-66ad-3a19-94cc545bd557@collabora.com>
 <1090744a-3de6-1dc2-5efe-b7caae45223a@huawei.com>
 <644e10ca-87b8-b553-db96-984c0b2c6da1@collabora.com>
 <93173400-1d37-09ed-57ef-931550b5a582@huawei.com>
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In-Reply-To: <93173400-1d37-09ed-57ef-931550b5a582@huawei.com>
Precedence: bulk

On Mon, Nov 15, 2021 at 11:34:59AM +0800, Yunsheng Lin wrote:
> On 2021/11/12 17:21, Guillaume Tucker wrote:
> > On 09/11/2021 12:02, Yunsheng Lin wrote:
> >> On 2021/11/9 17:58, Guillaume Tucker wrote:
> >>> Hi Yunsheng,
> >>>
> >>> Please see the bisection report below about a boot failure on
> >>> rk3288-rock2-square which is pointing to this patch.  The issue
> >>> appears to only happen with CONFIG_ARM_LPAE=y.
> >>>
> >>> Reports aren't automatically sent to the public while we're
> >>> trialing new bisection features on kernelci.org but this one
> >>> looks valid.
> >>>
> >>> Some more details can be found here:
> >>>
> >>>   https://linux.kernelci.org/test/case/id/6189968c3ec0a3c06e3358fe/
> >>>
> >>> Here's the same revision on the same platform booting fine with a
> >>> plain multi_v7_defconfig build:
> >>>
> >>>   https://linux.kernelci.org/test/plan/id/61899d322c0e9fee7e3358ec/
> >>>
> >>> Please let us know if you need any help debugging this issue or
> >>> if you have a fix to try.
> >>
> >> The patch below is removing the dma mapping support in page pool
> >> for 32 bit systems with 64 bit dma address, so it seems there
> >> is indeed a a drvier using the the page pool with PP_FLAG_DMA_MAP
> >> flags set in a 32 bit systems with 64 bit dma address.
> >>
> >> It seems we might need to revert the below patch or implement the
> >> DMA-mapping tracking support in the driver as mentioned in the below
> >> commit log.
> >>
> >> which ethernet driver do you use in your system?
> > 
> > Thanks for taking a look and sorry for the slow reply.  Here's a
> > booting test job with LPAE disabled:
> > 
> >     https://linux.kernelci.org/test/plan/id/618dbb81c60c4d94503358f1/
> >     https://storage.kernelci.org/mainline/master/v5.15-12452-g5833291ab6de/arm/multi_v7_defconfig/gcc-10/lab-collabora/baseline-nfs-rk3288-rock2-square.html#L812
> > 
> > [    8.314523] rk_gmac-dwmac ff290000.ethernet eth0: Link is Up - 1Gbps/Full - flow control rx/tx
> > 
> > So the driver is drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> 
> Thanks for the report, this patch seems to cause problem for 32-bit
> system with LPAE enabled.
> 
> As LPAE seems like a common feature for 32 bits system, this patch
> might need to be reverted.
> 
> @Jesper, @Ilias, what do you think?


So enabling LPAE also enables CONFIG_ARCH_DMA_ADDR_T_64BIT on that board?
Doing a quick grep only selects that for XEN.  I am ok reverting that,  but
I think we need to understand how the dma address ended up being 64bit.

Regards
/Ilias

> 
> > 
> > Best wishes,
> > Guillaume
> > 
> > 
> >>> GitHub: https://github.com/kernelci/kernelci-project/issues/71
> >>>
> >>> -------------------------------------------------------------------------------
> >>>
> >>> * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
> >>> * This automated bisection report was sent to you on the basis  *
> >>> * that you may be involved with the breaking commit it has      *
> >>> * found.  No manual investigation has been done to verify it,   *
> >>> * and the root cause of the problem may be somewhere else.      *
> >>> *                                                               *
> >>> * If you do send a fix, please include this trailer:            *
> >>> *   Reported-by: "kernelci.org bot" <bot@kernelci.org>          *
> >>> *                                                               *
> >>> * Hope this helps!                                              *
> >>> * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
> >>>
> >>> mainline/master bisection: baseline.login on rk3288-rock2-square
> >>>
> >>> Summary:
> >>>   Start:      e851dfae4371d Merge tag 'kgdb-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux
> >>>   Plain log:  https://storage.kernelci.org/mainline/master/v5.15-11387-ge851dfae4371/arm/multi_v7_defconfig+CONFIG_EFI=y+CONFIG_ARM_LPAE=y/gcc-10/lab-collabora/baseline-rk3288-rock2-square.txt
> >>>   HTML log:   https://storage.kernelci.org/mainline/master/v5.15-11387-ge851dfae4371/arm/multi_v7_defconfig+CONFIG_EFI=y+CONFIG_ARM_LPAE=y/gcc-10/lab-collabora/baseline-rk3288-rock2-square.html
> >>>   Result:     d00e60ee54b12 page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA
> >>>
> >>> Checks:
> >>>   revert:     PASS
> >>>   verify:     PASS
> >>>
> >>> Parameters:
> >>>   Tree:       mainline
> >>>   URL:        https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> >>>   Branch:     master
> >>>   Target:     rk3288-rock2-square
> >>>   CPU arch:   arm
> >>>   Lab:        lab-collabora
> >>>   Compiler:   gcc-10
> >>>   Config:     multi_v7_defconfig+CONFIG_EFI=y+CONFIG_ARM_LPAE=y
> >>>   Test case:  baseline.login
> >>>
> >>> Breaking commit found:
> >>>
> >>> -------------------------------------------------------------------------------
> >>> commit d00e60ee54b12de945b8493cf18c1ada9e422514
> >>> Author: Yunsheng Lin <linyunsheng@huawei.com>
> >>> Date:   Wed Oct 13 17:19:20 2021 +0800
> >>>
> >>>     page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA
> >>>     
> >>>
> >>> On 13/10/2021 10:19, Yunsheng Lin wrote:
> >>>> As the 32-bit arch with 64-bit DMA seems to rare those days,
> >>>> and page pool might carry a lot of code and complexity for
> >>>> systems that possibly.
> >>>>
> >>>> So disable dma mapping support for such systems, if drivers
> >>>> really want to work on such systems, they have to implement
> >>>> their own DMA-mapping fallback tracking outside page_pool.
> >>>>
> >>>> Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> >>>> Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
> >>>> ---
> >>>> V6: Drop pp page tracking support
> >>>> ---
> >>>>  include/linux/mm_types.h | 13 +------------
> >>>>  include/net/page_pool.h  | 12 +-----------
> >>>>  net/core/page_pool.c     | 10 ++++++----
> >>>>  3 files changed, 8 insertions(+), 27 deletions(-)
> >>>>
> >>>> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> >>>> index 7f8ee09c711f..436e0946d691 100644
> >>>> --- a/include/linux/mm_types.h
> >>>> +++ b/include/linux/mm_types.h
> >>>> @@ -104,18 +104,7 @@ struct page {
> >>>>  			struct page_pool *pp;
> >>>>  			unsigned long _pp_mapping_pad;
> >>>>  			unsigned long dma_addr;
> >>>> -			union {
> >>>> -				/**
> >>>> -				 * dma_addr_upper: might require a 64-bit
> >>>> -				 * value on 32-bit architectures.
> >>>> -				 */
> >>>> -				unsigned long dma_addr_upper;
> >>>> -				/**
> >>>> -				 * For frag page support, not supported in
> >>>> -				 * 32-bit architectures with 64-bit DMA.
> >>>> -				 */
> >>>> -				atomic_long_t pp_frag_count;
> >>>> -			};
> >>>> +			atomic_long_t pp_frag_count;
> >>>>  		};
> >>>>  		struct {	/* slab, slob and slub */
> >>>>  			union {
> >>>> diff --git a/include/net/page_pool.h b/include/net/page_pool.h
> >>>> index a4082406a003..3855f069627f 100644
> >>>> --- a/include/net/page_pool.h
> >>>> +++ b/include/net/page_pool.h
> >>>> @@ -216,24 +216,14 @@ static inline void page_pool_recycle_direct(struct page_pool *pool,
> >>>>  	page_pool_put_full_page(pool, page, true);
> >>>>  }
> >>>>  
> >>>> -#define PAGE_POOL_DMA_USE_PP_FRAG_COUNT	\
> >>>> -		(sizeof(dma_addr_t) > sizeof(unsigned long))
> >>>> -
> >>>>  static inline dma_addr_t page_pool_get_dma_addr(struct page *page)
> >>>>  {
> >>>> -	dma_addr_t ret = page->dma_addr;
> >>>> -
> >>>> -	if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT)
> >>>> -		ret |= (dma_addr_t)page->dma_addr_upper << 16 << 16;
> >>>> -
> >>>> -	return ret;
> >>>> +	return page->dma_addr;
> >>>>  }
> >>>>  
> >>>>  static inline void page_pool_set_dma_addr(struct page *page, dma_addr_t addr)
> >>>>  {
> >>>>  	page->dma_addr = addr;
> >>>> -	if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT)
> >>>> -		page->dma_addr_upper = upper_32_bits(addr);
> >>>>  }
> >>>>  
> >>>>  static inline void page_pool_set_frag_count(struct page *page, long nr)
> >>>> diff --git a/net/core/page_pool.c b/net/core/page_pool.c
> >>>> index 1a6978427d6c..9b60e4301a44 100644
> >>>> --- a/net/core/page_pool.c
> >>>> +++ b/net/core/page_pool.c
> >>>> @@ -49,6 +49,12 @@ static int page_pool_init(struct page_pool *pool,
> >>>>  	 * which is the XDP_TX use-case.
> >>>>  	 */
> >>>>  	if (pool->p.flags & PP_FLAG_DMA_MAP) {
> >>>> +		/* DMA-mapping is not supported on 32-bit systems with
> >>>> +		 * 64-bit DMA mapping.
> >>>> +		 */
> >>>> +		if (sizeof(dma_addr_t) > sizeof(unsigned long))
> >>>> +			return -EOPNOTSUPP;
> >>>> +
> >>>>  		if ((pool->p.dma_dir != DMA_FROM_DEVICE) &&
> >>>>  		    (pool->p.dma_dir != DMA_BIDIRECTIONAL))
> >>>>  			return -EINVAL;
> >>>> @@ -69,10 +75,6 @@ static int page_pool_init(struct page_pool *pool,
> >>>>  		 */
> >>>>  	}
> >>>>  
> >>>> -	if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT &&
> >>>> -	    pool->p.flags & PP_FLAG_PAGE_FRAG)
> >>>> -		return -EINVAL;
> >>>> -
> >>>>  	if (ptr_ring_init(&pool->ring, ring_qsize, GFP_KERNEL) < 0)
> >>>>  		return -ENOMEM;
> >>>>  
> >>>>
> >>>
> >>>
> >>>
> >>> Git bisection log:
> >>>
> >>> -------------------------------------------------------------------------------
> >>> git bisect start
> >>> # good: [bfc484fe6abba4b89ec9330e0e68778e2a9856b2] Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
> >>> git bisect good bfc484fe6abba4b89ec9330e0e68778e2a9856b2
> >>> # bad: [e851dfae4371d3c751f1e18e8eb5eba993de1467] Merge tag 'kgdb-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux
> >>> git bisect bad e851dfae4371d3c751f1e18e8eb5eba993de1467
> >>> # bad: [dcd68326d29b62f3039e4f4d23d3e38f24d37360] Merge tag 'devicetree-for-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux
> >>> git bisect bad dcd68326d29b62f3039e4f4d23d3e38f24d37360
> >>> # bad: [b7b98f868987cd3e86c9bd9a6db048614933d7a0] Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
> >>> git bisect bad b7b98f868987cd3e86c9bd9a6db048614933d7a0
> >>> # bad: [9fd3d5dced976640f588e0a866b9611db2d2cb37] net: ethernet: ave: Add compatible string and SoC-dependent data for NX1 SoC
> >>> git bisect bad 9fd3d5dced976640f588e0a866b9611db2d2cb37
> >>> # good: [a96d317fb1a30b9f323548eb2ff05d4e4600ead9] ethernet: use eth_hw_addr_set()
> >>> git bisect good a96d317fb1a30b9f323548eb2ff05d4e4600ead9
> >>> # good: [f5396b8a663f7a78ee5b75a47ee524b40795b265] ice: switchdev slow path
> >>> git bisect good f5396b8a663f7a78ee5b75a47ee524b40795b265
> >>> # good: [20c3d9e45ba630a7156d682a40988c0e96be1b92] hamradio: use dev_addr_set() for setting device address
> >>> git bisect good 20c3d9e45ba630a7156d682a40988c0e96be1b92
> >>> # bad: [a64b442137669c9e839c6a70965989b01b1253b7] net: dpaa2: add support for manual setup of IRQ coalesing
> >>> git bisect bad a64b442137669c9e839c6a70965989b01b1253b7
> >>> # good: [30fc7efa38f21afa48b0be6bf2053e4c10ae2c78] net, neigh: Reject creating NUD_PERMANENT with NTF_MANAGED entries
> >>> git bisect good 30fc7efa38f21afa48b0be6bf2053e4c10ae2c78
> >>> # bad: [13ad5ccc093ff448b99ac7e138e91e78796adb48] dt-bindings: net: dsa: qca8k: Document qca,sgmii-enable-pll
> >>> git bisect bad 13ad5ccc093ff448b99ac7e138e91e78796adb48
> >>> # good: [40088915f547b52635f022c1e1e18df65ae3153a] Merge branch 'octeontx2-af-miscellaneous-changes-for-cpt'
> >>> git bisect good 40088915f547b52635f022c1e1e18df65ae3153a
> >>> # bad: [fdbf35df9c091db9c46e57e9938e3f7a4f603a7c] dt-bindings: net: dsa: qca8k: Add SGMII clock phase properties
> >>> git bisect bad fdbf35df9c091db9c46e57e9938e3f7a4f603a7c
> >>> # bad: [bacc8daf97d4199316328a5d18eeafbe447143c5] xen-netback: Remove redundant initialization of variable err
> >>> git bisect bad bacc8daf97d4199316328a5d18eeafbe447143c5
> >>> # bad: [d00e60ee54b12de945b8493cf18c1ada9e422514] page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA
> >>> git bisect bad d00e60ee54b12de945b8493cf18c1ada9e422514
> >>> # first bad commit: [d00e60ee54b12de945b8493cf18c1ada9e422514] page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA
> >>> -------------------------------------------------------------------------------
> >>> .
> >>>
> > 
> > .
> >