| Message ID | 20210719054138.198373-1-gshan@redhat.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | mm/debug_vm_pgtable: Enhancements | expand |
Hi Anshuman, On 7/19/21 3:41 PM, 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 old implementation. > PATCH[12] fixes the issue of corrupted page flag for ARM64 > > Changelog > ========= > v2: > * Rename struct vm_pgtable_debug to struct pgtable_debug_args. > The parameter name to various test functions are renamed > to "@args" (Anshuman) > * Code changes as suggested by Anshuman (Anshuman) > Please ignore v2. I will post v3 to fix couple of issues in v2: (1) The subjects of PATCH[5/12] and PATCH[9/12] should be fixed to start with "mm/debug_vm_pgtable". (2) "WARN_ON(!pud_none(pud))" is missed in PATCH[9/12]. Otherwise, build warning for unused variable @pud is raised. (3) Build warnings for unused variables in separate patches are raised, reported by 0-DAY CI Kernel Test Service. Thanks, Gavin > Gavin Shan (12): > mm/debug_vm_pgtable: Introduce struct pgtable_debug_args > mm/debug_vm_pgtable: Use struct pgtable_debug_args in basic tests > mm/debug_vm_pgtable: Use struct pgtable_debug_args in leaf and > savewrite tests > mm/debug_vm_pgtable: Use struct pgtable_debug_args in protnone and > devmap tests > mm/vm_debug_pgtable: Use struct pgtable_debug_args in soft_dirty and > swap tests > mm/debug_vm_pgtable: Use struct pgtable_debug_args in migration and > thp tests > mm/debug_vm_pgtable: Use struct pgtable_debug_args in PTE modifying > tests > mm/debug_vm_pgtable: Use struct pgtable_debug_args in PMD > mm/vm_debug_pgtable: Use struct pgtable_debug_args in PUD modifying > tests > mm/debug_vm_pgtable: Use struct pgtable_debug_args in PGD and P4D > modifying tests > mm/debug_vm_pgtable: Remove unused code > mm/debug_vm_pgtable: Fix corrupted page flag > > mm/debug_vm_pgtable.c | 849 ++++++++++++++++++++++++------------------ > 1 file changed, 479 insertions(+), 370 deletions(-) >
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 old implementation. PATCH[12] fixes the issue of corrupted page flag for ARM64 Changelog ========= v2: * Rename struct vm_pgtable_debug to struct pgtable_debug_args. The parameter name to various test functions are renamed to "@args" (Anshuman) * Code changes as suggested by Anshuman (Anshuman) Gavin Shan (12): mm/debug_vm_pgtable: Introduce struct pgtable_debug_args mm/debug_vm_pgtable: Use struct pgtable_debug_args in basic tests mm/debug_vm_pgtable: Use struct pgtable_debug_args in leaf and savewrite tests mm/debug_vm_pgtable: Use struct pgtable_debug_args in protnone and devmap tests mm/vm_debug_pgtable: Use struct pgtable_debug_args in soft_dirty and swap tests mm/debug_vm_pgtable: Use struct pgtable_debug_args in migration and thp tests mm/debug_vm_pgtable: Use struct pgtable_debug_args in PTE modifying tests mm/debug_vm_pgtable: Use struct pgtable_debug_args in PMD mm/vm_debug_pgtable: Use struct pgtable_debug_args in PUD modifying tests mm/debug_vm_pgtable: Use struct pgtable_debug_args in PGD and P4D modifying tests mm/debug_vm_pgtable: Remove unused code mm/debug_vm_pgtable: Fix corrupted page flag mm/debug_vm_pgtable.c | 849 ++++++++++++++++++++++++------------------ 1 file changed, 479 insertions(+), 370 deletions(-)