On 8/2/21 11:34 AM, Gavin Shan wrote: > There are couple of issues with current implementations and this series > tries to resolve the issues: > > (a) All needed information are scattered in variables, passed to various > test functions. The code is organized in pretty much relaxed fashion. > > (b) The page isn't allocated from buddy during page table entry modifying > tests. The page can be invalid, conflicting to the implementations > of set_xxx_at() on ARM64. The target page is accessed so that the > iCache can be flushed when execution permission is given on ARM64. > Besides, the target page can be unmapped and accessing to it causes > kernel crash. > > "struct pgtable_debug_args" is introduced to address issue (a). For issue > (b), the used page is allocated from buddy in page table entry modifying > tests. The corresponding tets will be skipped if we fail to allocate the > (huge) page. For other test cases, the original page around to kernel > symbol (@start_kernel) is still used. > > The patches are organized as below. PATCH[2-10] could be combined to one > patch, but it will make the review harder: > > PATCH[1] introduces "struct pgtable_debug_args" as place holder of all > needed information. With it, the old and new implementation > can coexist. > PATCH[2-10] uses "struct pgtable_debug_args" in various test functions. > PATCH[11] removes the unused code for old implementation. > PATCH[12] fixes the issue of corrupted page flag for ARM64 > > Changelog > ========= > v5: > * Pick r-bs from Anshuman and rebase to 5.14.rc4 (Gavin) > * Use args->start_p4dp to free p4d entries (Anshuman) > * Introduce helper to allocate huge page in init_arg() (Anshuman) > * Bail early if the allocated page doesn't exist in > swap_migration_tests() and correct the comments (Anshuman) > * Add fixes tag to PATCH[v4 12/12] (Christophe) > * Address misc comments (Anshuman) Apart from the proposed changes discussed for the first patch [PATCH 1/12], this series overall looks good now. It clears build tests on all supported platforms. I was able to test this on arm64 and x86 platforms with various functional config combinations. It would be still great if others can take a look as well. - Anshuman
