[PATCH] drm/ttm: ioremap buffer according to TTM mem caching setting

Daniel Vetter daniel at ffwll.ch
Thu Mar 11 13:06:05 UTC 2021


On Thu, Mar 04, 2021 at 08:46:26AM +0100, Christian König wrote:
> Hi Oak,
> 
> as far as I know some architectures like PowerPC/ARM/MIPS need that. And we
> at least officially support PowerPC and ARM and MIPS is best effort and
> shouldn't break if possible.
> 
> Thomas just recently had a whole bunch of DMA-buf patches to also fix that
> up for DMA-bufs vmap as well, previously we have just been casting away the
> __iomem and hoped that it always works.

On that, rolling out struct dma_buf_map to ttm and drivers I think would
clean up a lot of this __iomem handling rather nicely.
-Daniel

> 
> Regards,
> Christian.
> 
> Am 03.03.21 um 21:59 schrieb Zeng, Oak:
> > 
> > [AMD Official Use Only - Internal Distribution Only]
> > 
> > 
> > Hi Christian,
> > 
> > Can you explain why __iomem annotation is mandatory for amdgpu driver?
> > If this is the case, we can’t switch to memremap. The only fix seems to
> > me is add a #ifdef __x86_64__ to the ioremap_cache codes.
> > 
> > Regards,
> > 
> > Oak
> > 
> > *From:* Christian König <ckoenig.leichtzumerken at gmail.com>
> > *Sent:* Wednesday, March 3, 2021 5:46 AM
> > *To:* Zeng, Oak <Oak.Zeng at amd.com>; amd-gfx at lists.freedesktop.org;
> > dri-devel at lists.freedesktop.org; Daniel Vetter <daniel at ffwll.ch>; Dave
> > Airlie <airlied at redhat.com>; Thomas Hellström (Intel)
> > <thomas_os at shipmail.org>; dan.j.williams at intel.com
> > *Cc:* kbuild-all at lists.01.org; Kuehling, Felix <Felix.Kuehling at amd.com>;
> > Kasiviswanathan, Harish <Harish.Kasiviswanathan at amd.com>; Deucher,
> > Alexander <Alexander.Deucher at amd.com>; Huang, JinHuiEric
> > <JinHuiEric.Huang at amd.com>; Koenig, Christian <Christian.Koenig at amd.com>
> > *Subject:* Re: [PATCH] drm/ttm: ioremap buffer according to TTM mem
> > caching setting
> > 
> > Hi Oak,
> > 
> > 
> >     config: parisc-randconfig-r012-20210302 (attached as .config)
> > 
> > 
> > It's not the Intel driver build which fails here, but the build bot is
> > just hosted by Intel.
> > 
> > The problem is that the parisc architecture doesn't defines the
> > ioremap_cache() function.
> > 
> > I've looked at using memremap() instead of ioremap_cache(). The problem
> > is that we do support architectures with the TTM as well as amndgpu code
> > where the __iomem annotation is mandatory and correct.
> > 
> > Regards,
> > Christian.
> > 
> > Am 02.03.21 um 23:45 schrieb Zeng, Oak:
> > 
> >     [AMD Official Use Only - Internal Distribution Only]
> > 
> >     Hi Daniel, Thomas, Dan,
> > 
> >     Does below message mean the calling ioremap_cache failed intel’s
> >     driver build? I can see both ioremap_cache and ioremap_wc are
> >     defined in arch/x86/mm/ioremap.c – why ioremap_wc doesn’t break
> >     intel driver’s build?
> > 
> >     Are we supposed to use memremap (offset, size, MEMREMAP_WB) to
> >     replace ioremap_cache? When I read here
> >     https://lwn.net/Articles/653585/
> >     <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flwn.net%2FArticles%2F653585%2F&data=04%7C01%7COak.Zeng%40amd.com%7Cc047ecb316df47cde7ed08d8de3188d4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637503651624296472%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=ljCFrIfrYbb%2FXmKKS2TJ7dSQ7oCRNWoUhWS4gEBv%2FW4%3D&reserved=0>
> >     I felt that ioremap_cache returns an address annotated with _iomem
> >     while memremap returns an address without __iomem annotation. In
> >     our use case, GPU memory is treated as UEFI SPM (specific purpose
> >     memory). I am not very sure whether memremap (thus no __iomem
> >     annotation) is the right thing to do. What I am sure is, we have
> >     tested ioremap_cache and it works fine on AMD system.
> > 
> >     I will send out a test patch replacing ioremap_cache with
> >     ioremap_wc, to trigger Intel build robot to see whether it fails
> >     Intel build. I suppose it will not fail Intel build.
> > 
> >     Regards,
> > 
> >     Oak
> > 
> >     *From:* Christian König <ckoenig.leichtzumerken at gmail.com>
> >     <mailto:ckoenig.leichtzumerken at gmail.com>
> >     *Sent:* Tuesday, March 2, 2021 6:31 AM
> >     *To:* amd-gfx at lists.freedesktop.org
> >     <mailto:amd-gfx at lists.freedesktop.org>;
> >     dri-devel at lists.freedesktop.org
> >     <mailto:dri-devel at lists.freedesktop.org>; Daniel Vetter
> >     <daniel at ffwll.ch> <mailto:daniel at ffwll.ch>; Dave Airlie
> >     <airlied at redhat.com> <mailto:airlied at redhat.com>; Thomas Hellström
> >     (Intel) <thomas_os at shipmail.org> <mailto:thomas_os at shipmail.org>
> >     *Cc:* Zeng, Oak <Oak.Zeng at amd.com> <mailto:Oak.Zeng at amd.com>;
> >     kbuild-all at lists.01.org <mailto:kbuild-all at lists.01.org>;
> >     Kuehling, Felix <Felix.Kuehling at amd.com>
> >     <mailto:Felix.Kuehling at amd.com>; Kasiviswanathan, Harish
> >     <Harish.Kasiviswanathan at amd.com>
> >     <mailto:Harish.Kasiviswanathan at amd.com>; Deucher, Alexander
> >     <Alexander.Deucher at amd.com> <mailto:Alexander.Deucher at amd.com>;
> >     Huang, JinHuiEric <JinHuiEric.Huang at amd.com>
> >     <mailto:JinHuiEric.Huang at amd.com>; Koenig, Christian
> >     <Christian.Koenig at amd.com> <mailto:Christian.Koenig at amd.com>
> >     *Subject:* Re: [PATCH] drm/ttm: ioremap buffer according to TTM
> >     mem caching setting
> > 
> >     Hi guys,
> > 
> >     adding the usual suspects direct. Does anybody of hand know how to
> >     check if an architecture supports ioremap_cache()?
> > 
> >     For now we only need this on X86, but I would feel better if we
> >     don't use an #ifdef here.
> > 
> >     Regards,
> >     Christian.
> > 
> >     Am 02.03.21 um 05:12 schrieb kernel test robot:
> > 
> >         Hi Oak,
> > 
> > 
> >         Thank you for the patch! Yet something to improve:
> > 
> > 
> >         [auto build test ERROR on drm-intel/for-linux-next]
> > 
> >         [also build test ERROR on drm-tip/drm-tip linus/master v5.12-rc1 next-20210302]
> > 
> >         [cannot apply to tegra-drm/drm/tegra/for-next drm-exynos/exynos-drm-next drm/drm-next]
> > 
> >         [If your patch is applied to the wrong git tree, kindly drop us a note.
> > 
> >         And when submitting patch, we suggest to use '--base' as documented in
> > 
> >         https://git-scm.com/docs/git-format-patch  <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit-scm.com%2Fdocs%2Fgit-format-patch&data=04%7C01%7COak.Zeng%40amd.com%7Cc047ecb316df47cde7ed08d8de3188d4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637503651624306464%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=3f5ib%2FlZ6DXXF%2Bk1rXPKGu1IkOhXHdkUmX3obtuIRtA%3D&reserved=0>]
> > 
> > 
> >         url:https://github.com/0day-ci/linux/commits/Oak-Zeng/drm-ttm-ioremap-buffer-according-to-TTM-mem-caching-setting/20210302-064500  <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2F0day-ci%2Flinux%2Fcommits%2FOak-Zeng%2Fdrm-ttm-ioremap-buffer-according-to-TTM-mem-caching-setting%2F20210302-064500&data=04%7C01%7COak.Zeng%40amd.com%7Cc047ecb316df47cde7ed08d8de3188d4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637503651624306464%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=Y9h9ZHM7d2Sqo3XQWr%2Frpb2DAk9SkHFIm5nD4ABFNbE%3D&reserved=0>
> > 
> >         base:   git://anongit.freedesktop.org/drm-intel for-linux-next
> > 
> >         config: parisc-randconfig-r012-20210302 (attached as .config)
> > 
> >         compiler: hppa-linux-gcc (GCC) 9.3.0
> > 
> >         reproduce (this is a W=1 build):
> > 
> >                  wgethttps://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross  <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fraw.githubusercontent.com%2Fintel%2Flkp-tests%2Fmaster%2Fsbin%2Fmake.cross&data=04%7C01%7COak.Zeng%40amd.com%7Cc047ecb316df47cde7ed08d8de3188d4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637503651624316464%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=wGo3Nwk4mWZjb2W3E7qKf3FtKzLOxCVmQu1zd2rmzRU%3D&reserved=0>  -O ~/bin/make.cross
> > 
> >                  chmod +x ~/bin/make.cross
> > 
> >                  #https://github.com/0day-ci/linux/commit/225bb3711439ec559dd72ae5af8e62d34ea60a64  <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2F0day-ci%2Flinux%2Fcommit%2F225bb3711439ec559dd72ae5af8e62d34ea60a64&data=04%7C01%7COak.Zeng%40amd.com%7Cc047ecb316df47cde7ed08d8de3188d4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637503651624316464%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=kOz18UAawmA4SZ6IrCGRt4HISfsmmjfGN2TUgAtm0Ak%3D&reserved=0>
> > 
> >                  git remote add linux-reviewhttps://github.com/0day-ci/linux  <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2F0day-ci%2Flinux&data=04%7C01%7COak.Zeng%40amd.com%7Cc047ecb316df47cde7ed08d8de3188d4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637503651624326458%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=QnKs47gjzAz%2Fjv%2FAO6H%2BwYNQF6mdk1D8dCNveW0YHuM%3D&reserved=0>
> > 
> >                  git fetch --no-tags linux-review Oak-Zeng/drm-ttm-ioremap-buffer-according-to-TTM-mem-caching-setting/20210302-064500
> > 
> >                  git checkout 225bb3711439ec559dd72ae5af8e62d34ea60a64
> > 
> >                  # save the attached .config to linux build tree
> > 
> >                  COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=parisc
> > 
> > 
> >         If you fix the issue, kindly add following tag as appropriate
> > 
> >         Reported-by: kernel test robot<lkp at intel.com>  <mailto:lkp at intel.com>
> > 
> > 
> >         All errors (new ones prefixed by >>):
> > 
> > 
> >             drivers/gpu/drm/ttm/ttm_bo_util.c: In function 'ttm_resource_ioremap':
> > 
> >                 drivers/gpu/drm/ttm/ttm_bo_util.c:95:11: error: implicit declaration of function 'ioremap_cache'; did you mean 'ioremap_uc'? [-Werror=implicit-function-declaration]
> > 
> >                95 |    addr = ioremap_cache(mem->bus.offset, bus_size);
> > 
> >                   |           ^~~~~~~~~~~~~
> > 
> >                   |           ioremap_uc
> > 
> >             drivers/gpu/drm/ttm/ttm_bo_util.c:95:9: warning: assignment to 'void *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
> > 
> >                95 |    addr = ioremap_cache(mem->bus.offset, bus_size);
> > 
> >                   |         ^
> > 
> >             drivers/gpu/drm/ttm/ttm_bo_util.c: In function 'ttm_bo_ioremap':
> > 
> >             drivers/gpu/drm/ttm/ttm_bo_util.c:379:17: warning: assignment to 'void *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
> > 
> >               379 |    map->virtual = ioremap_cache(bo->mem.bus.offset + offset,
> > 
> >                   |                 ^
> > 
> >             drivers/gpu/drm/ttm/ttm_bo_util.c: In function 'ttm_bo_vmap':
> > 
> >             drivers/gpu/drm/ttm/ttm_bo_util.c:500:16: warning: assignment to 'void *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
> > 
> >               500 |    vaddr_iomem = ioremap_cache(mem->bus.offset,
> > 
> >                   |                ^
> > 
> >             cc1: some warnings being treated as errors
> > 
> > 
> > 
> >         vim +95 drivers/gpu/drm/ttm/ttm_bo_util.c
> > 
> > 
> >              74
> > 
> >              75  static int ttm_resource_ioremap(struct ttm_bo_device *bdev,
> > 
> >              76                                struct ttm_resource *mem,
> > 
> >              77                                void **virtual)
> > 
> >              78  {
> > 
> >              79          int ret;
> > 
> >              80          void *addr;
> > 
> >              81
> > 
> >              82          *virtual = NULL;
> > 
> >              83          ret = ttm_mem_io_reserve(bdev, mem);
> > 
> >              84          if (ret || !mem->bus.is_iomem)
> > 
> >              85                  return ret;
> > 
> >              86
> > 
> >              87          if (mem->bus.addr) {
> > 
> >              88                  addr = mem->bus.addr;
> > 
> >              89          } else {
> > 
> >              90                  size_t bus_size = (size_t)mem->num_pages << PAGE_SHIFT;
> > 
> >              91
> > 
> >              92                  if (mem->bus.caching == ttm_write_combined)
> > 
> >              93                         addr = ioremap_wc(mem->bus.offset, bus_size);
> > 
> >              94                  else if (mem->bus.caching == ttm_cached)
> > 
> >            > 95                         addr = ioremap_cache(mem->bus.offset, bus_size);
> > 
> >              96                  else
> > 
> >              97                         addr = ioremap(mem->bus.offset, bus_size);
> > 
> >              98                  if (!addr) {
> > 
> >              99                         ttm_mem_io_free(bdev, mem);
> > 
> >             100                         return -ENOMEM;
> > 
> >             101                  }
> > 
> >             102          }
> > 
> >             103          *virtual = addr;
> > 
> >             104          return 0;
> > 
> >             105  }
> > 
> >             106
> > 
> > 
> >         ---
> > 
> >         0-DAY CI Kernel Test Service, Intel Corporation
> > 
> >         https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org  <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.01.org%2Fhyperkitty%2Flist%2Fkbuild-all%40lists.01.org&data=04%7C01%7COak.Zeng%40amd.com%7Cc047ecb316df47cde7ed08d8de3188d4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637503651624326458%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=MY6tEGVY0X4VyS750dYmsfVoR71Zp78YdxuqqRljnsI%3D&reserved=0>
> > 
> > 
> > 
> > 
> >         _______________________________________________
> > 
> >         amd-gfx mailing list
> > 
> >         amd-gfx at lists.freedesktop.org  <mailto:amd-gfx at lists.freedesktop.org>
> > 
> >         https://lists.freedesktop.org/mailman/listinfo/amd-gfx  <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfx&data=04%7C01%7COak.Zeng%40amd.com%7Cc047ecb316df47cde7ed08d8de3188d4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637503651624336455%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=Or3tWmS5M6mXOaFP4FHsEbg0rqoizNGpTl6JEkD6fac%3D&reserved=0>
> > 
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch


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