From: Andrii Nakryiko Date: Wed, 6 Mar 2024 18:19:04 +0000 (-0800) Subject: Merge branch 'mm-enforce-ioremap-address-space-and-introduce-sparse-vm_area' X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=9a9d1d36050e486822dc54990c896761b04e7446;p=linux.git Merge branch 'mm-enforce-ioremap-address-space-and-introduce-sparse-vm_area' Alexei Starovoitov says: ==================== mm: Enforce ioremap address space and introduce sparse vm_area From: Alexei Starovoitov v3 -> v4 - dropped VM_XEN patch for now. It will be in the follow up. - fixed constant as pointed out by Mike v2 -> v3 - added Christoph's reviewed-by to patch 1 - cap commit log lines to 75 chars - factored out common checks in patch 3 into helper - made vm_area_unmap_pages() return void There are various users of kernel virtual address space: vmalloc, vmap, ioremap, xen. - vmalloc use case dominates the usage. Such vm areas have VM_ALLOC flag and these areas are treated differently by KASAN. - the areas created by vmap() function should be tagged with VM_MAP (as majority of the users do). - ioremap areas are tagged with VM_IOREMAP and vm area start is aligned to size of the area unlike vmalloc/vmap. - there is also xen usage that is marked as VM_IOREMAP, but it doesn't call ioremap_page_range() unlike all other VM_IOREMAP users. To clean this up a bit, enforce that ioremap_page_range() checks the range and VM_IOREMAP flag. In addition BPF would like to reserve regions of kernel virtual address space and populate it lazily, similar to xen use cases. For that reason, introduce VM_SPARSE flag and vm_area_[un]map_pages() helpers to populate this sparse area. In the end the /proc/vmallocinfo will show "vmalloc" "vmap" "ioremap" "sparse" categories for different kinds of address regions. ioremap, sparse will return zero when dumped through /proc/kcore ==================== Link: https://lore.kernel.org/r/20240305030516.41519-1-alexei.starovoitov@gmail.com Signed-off-by: Andrii Nakryiko --- 9a9d1d36050e486822dc54990c896761b04e7446