On 8/2/21 5:39 AM, Gavin Shan wrote: > Hi Anshuman, > > On 7/29/21 5:14 PM, Anshuman Khandual wrote: >> On 7/27/21 11:43 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 access 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 >>> ========= >>> v4: >>> * Determine the page allocation method according to >>> MAX_ORDER (Anshuman) >>> * Move existing comments to init_args() (Anshuman) >>> * Code refactoring as suggested by Anshuman (Anshuman) >>> * Improved commit log and add comments for flush_dcache_page() >>> in PATCH[v4 12/12] (Anshuman) >>> * Address misc comments (Anshuman >> >> This series builds ok on all supported platforms but should also be tested >> on them as well i.e s390, ppc, arc and riscv. I was able to do some tests >> on arm64 and x86 platforms. >> > > I had tests on the platforms except arc as it's not supported by QEMU yet. > The test is pretty simple to boot the kernel and see if there is any warning > raised from mm/debug_vm_pgtable. Everything looks good. Sure, that should be enough. > > The test was done on v5, which will be posted pretty soon. Thanks again for > your continuous review. Please also do copy Vineet Gupta <vgupta@xxxxxxxxxxxx> for ARC in the next version. - Anshuman
