search for: copy_user_pag

...examples which is why > I think adding flush_kernel_dcache_page() is an already lost cause. In lots of cases kmap is needed to just modify kernel memory not to modify userland memory (where get/put_user is more commonly used instead..), there's no cache aliasing in such case. > Actually copy_user_page() is unused in the main kernel. The big > problem is copy_user_highpage() but that's mostly highly optimised by > the VIPT architectures (in other words you can fiddle with kmap without > impacting it). copy_user_page is not unused, it's called precisely by copy_user_highpage, w...

...t physically > tagged data caches (they'll still suffer from the spectre-v1 fix, > although I exclude they have to suffer the SMAP > slowdown/feature). Those may require some additional flushing than the > current copy-user model requires. > > As a rule of thumb any arch where copy_user_page doesn't define as > copy_page will require some additional cache flushing after the > kmap. Supposedly with vmap, the vmap layer should have taken care of > that (I didn't verify that yet). vmap_page_range()/free_unmap_vmap_area() will call fluch_cache_vmap()/flush_cache_vunmap...

...referenced and dirty bits on > the kmapped pte to tell you what operation to do, but if your flush is > your invalidate, you simply assume the data needs flushing on kunmap > without checking anything. Except other archs like arm64 and sparc do the cache flushing on copy_to_user_page and copy_user_page, not on kunmap. #define copy_user_page(to,from,vaddr,pg) __cpu_copy_user_page(to, from, vaddr) void __cpu_copy_user_page(void *kto, const void *kfrom, unsigned long vaddr) { struct page *page = virt_to_page(kto); copy_page(kto, kfrom); flush_dcache_page(page); } #define copy_user_page(to, from...

On Tue, Mar 12, 2019 at 10:59:09AM +0800, Jason Wang wrote: > > On 2019/3/12 ??2:14, David Miller wrote: > > From: "Michael S. Tsirkin" <mst at redhat.com> > > Date: Mon, 11 Mar 2019 09:59:28 -0400 > > > > > On Mon, Mar 11, 2019 at 03:13:17PM +0800, Jason Wang wrote: > > > > On 2019/3/8 ??10:12, Christoph Hellwig wrote: > > >

On Tue, Mar 12, 2019 at 10:59:09AM +0800, Jason Wang wrote: > > On 2019/3/12 ??2:14, David Miller wrote: > > From: "Michael S. Tsirkin" <mst at redhat.com> > > Date: Mon, 11 Mar 2019 09:59:28 -0400 > > > > > On Mon, Mar 11, 2019 at 03:13:17PM +0800, Jason Wang wrote: > > > > On 2019/3/8 ??10:12, Christoph Hellwig wrote: > > >

...PUs with virtually indexed not physically tagged data caches (they'll still suffer from the spectre-v1 fix, although I exclude they have to suffer the SMAP slowdown/feature). Those may require some additional flushing than the current copy-user model requires. As a rule of thumb any arch where copy_user_page doesn't define as copy_page will require some additional cache flushing after the kmap. Supposedly with vmap, the vmap layer should have taken care of that (I didn't verify that yet). There are some accessories like copy_to_user_page() copy_from_user_page() that could work and obviously d...

On Mon, Mar 11, 2019 at 03:40:31PM +0800, Jason Wang wrote: > > On 2019/3/9 ??3:48, Andrea Arcangeli wrote: > > Hello Jeson, > > > > On Fri, Mar 08, 2019 at 04:50:36PM +0800, Jason Wang wrote: > > > Just to make sure I understand here. For boosting through huge TLB, do > > > you mean we can do that in the future (e.g by mapping more userspace > >

On Mon, Mar 11, 2019 at 03:40:31PM +0800, Jason Wang wrote: > > On 2019/3/9 ??3:48, Andrea Arcangeli wrote: > > Hello Jeson, > > > > On Fri, Mar 08, 2019 at 04:50:36PM +0800, Jason Wang wrote: > > > Just to make sure I understand here. For boosting through huge TLB, do > > > you mean we can do that in the future (e.g by mapping more userspace > >

...copy_page (void *to, void *from); ^1da177e4c3f41 include/asm-ia64/page.h Linus Torvalds 2005-04-16 67 ^1da177e4c3f41 include/asm-ia64/page.h Linus Torvalds 2005-04-16 68 /* ^1da177e4c3f41 include/asm-ia64/page.h Linus Torvalds 2005-04-16 69 * clear_user_page() and copy_user_page() can't be inline functions because ^1da177e4c3f41 include/asm-ia64/page.h Linus Torvalds 2005-04-16 70 * flush_dcache_page() can't be defined until later... ^1da177e4c3f41 include/asm-ia64/page.h Linus Torvalds 2005-04-16 71 */ ^1da177e4c3f41 include/asm-ia64/page....

...r_user_page' undeclared (first use in this function) /usr/src/linux/include/linux/highmem.h:93: error: (Each undeclared identifier is reported only once /usr/src/linux/include/linux/highmem.h:93: error: for each function it appears in.) /usr/src/linux/include/linux/highmem.h:132:41: macro "copy_user_page" requires 4 arguments, but only 3 given /usr/src/linux/include/linux/highmem.h: In function `copy_user_highpage': /usr/src/linux/include/linux/highmem.h:132: error: `copy_user_page' undeclared (first use in this function) In file included from /usr/include/linux/dma-mapping.h:13,...

...r_user_page' undeclared (first use in this function) /usr/src/linux/include/linux/highmem.h:87: error: (Each undeclared identifier is reported only once /usr/src/linux/include/linux/highmem.h:87: error: for each function it appears in.) /usr/src/linux/include/linux/highmem.h:119:41: macro "copy_user_page" requires 4 arguments, but only 3 given /usr/src/linux/include/linux/highmem.h: In function `copy_user_highpage': /usr/src/linux/include/linux/highmem.h:119: error: `copy_user_page' undeclared (first use in this function) In file included from /usr/include/linux/dma-mapping.h:13,...