Hi Anshuman, On 7/22/21 3:56 PM, Anshuman Khandual wrote:
On 7/19/21 6:36 PM, Gavin Shan wrote:This uses struct pgtable_debug_args in PTE modifying tests. The allocated page is used as set_pte_at() is used there. The tests are skipped if the allocated page doesn't exist. Besides, the unused variable @ptep and @pte_aligned in debug_vm_pgtable() are dropped.Please dont drop @ptep and @pte_aligned just yet.
We need to do so. Otherwise, there are build warning raised to complain something like 'unused variable'.
Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx> --- mm/debug_vm_pgtable.c | 75 ++++++++++++++++++++++--------------------- 1 file changed, 39 insertions(+), 36 deletions(-) diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index d32e55a95c55..eb6dda88e0d9 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -116,10 +116,7 @@ static void __init pte_basic_tests(struct pgtable_debug_args *args, int idx) WARN_ON(!pte_dirty(pte_wrprotect(pte_mkdirty(pte)))); }-static void __init pte_advanced_tests(struct mm_struct *mm,- struct vm_area_struct *vma, pte_t *ptep, - unsigned long pfn, unsigned long vaddr, - pgprot_t prot) +static void __init pte_advanced_tests(struct pgtable_debug_args *args) { pte_t pte;@@ -130,33 +127,38 @@ static void __init pte_advanced_tests(struct mm_struct *mm,*/pr_debug("Validating PTE advanced\n");- pte = pfn_pte(pfn, prot); - set_pte_at(mm, vaddr, ptep, pte); - ptep_set_wrprotect(mm, vaddr, ptep); - pte = ptep_get(ptep); + if (args->pte_pfn == ULONG_MAX) { + pr_debug("%s: Skipped\n", __func__); + return; + }Just return. Please dont call out "Skipped". Also this check should be performed before printing pr_debug("Validating PTE advanced\n"). The print indicates that the test has started.
Sure.
+ + pte = pfn_pte(args->pte_pfn, args->page_prot); + set_pte_at(args->mm, args->vaddr, args->ptep, pte); + ptep_set_wrprotect(args->mm, args->vaddr, args->ptep); + pte = ptep_get(args->ptep); WARN_ON(pte_write(pte)); - ptep_get_and_clear(mm, vaddr, ptep); - pte = ptep_get(ptep); + ptep_get_and_clear(args->mm, args->vaddr, args->ptep); + pte = ptep_get(args->ptep); WARN_ON(!pte_none(pte));- pte = pfn_pte(pfn, prot);+ pte = pfn_pte(args->pte_pfn, args->page_prot); pte = pte_wrprotect(pte); pte = pte_mkclean(pte); - set_pte_at(mm, vaddr, ptep, pte); + set_pte_at(args->mm, args->vaddr, args->ptep, pte); pte = pte_mkwrite(pte); pte = pte_mkdirty(pte); - ptep_set_access_flags(vma, vaddr, ptep, pte, 1); - pte = ptep_get(ptep); + ptep_set_access_flags(args->vma, args->vaddr, args->ptep, pte, 1); + pte = ptep_get(args->ptep); WARN_ON(!(pte_write(pte) && pte_dirty(pte))); - ptep_get_and_clear_full(mm, vaddr, ptep, 1); - pte = ptep_get(ptep); + ptep_get_and_clear_full(args->mm, args->vaddr, args->ptep, 1); + pte = ptep_get(args->ptep); WARN_ON(!pte_none(pte));- pte = pfn_pte(pfn, prot);+ pte = pfn_pte(args->pte_pfn, args->page_prot); pte = pte_mkyoung(pte); - set_pte_at(mm, vaddr, ptep, pte); - ptep_test_and_clear_young(vma, vaddr, ptep); - pte = ptep_get(ptep); + set_pte_at(args->mm, args->vaddr, args->ptep, pte); + ptep_test_and_clear_young(args->vma, args->vaddr, args->ptep); + pte = ptep_get(args->ptep); WARN_ON(pte_young(pte)); }@@ -617,20 +619,24 @@ static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp,} #endif /* PAGETABLE_P4D_FOLDED */-static void __init pte_clear_tests(struct mm_struct *mm, pte_t *ptep,- unsigned long pfn, unsigned long vaddr, - pgprot_t prot) +static void __init pte_clear_tests(struct pgtable_debug_args *args) { - pte_t pte = pfn_pte(pfn, prot); + pte_t pte;pr_debug("Validating PTE clear\n");+ if (args->pte_pfn == ULONG_MAX) { + pr_debug("%s: Skipped\n", __func__); + return; + }Just return. Please dont call out "Skipped". Also this check should be performed before printing pr_debug("Validating PTE clear\n"). The print indicates that the test has started.
Sure.
+ + pte = pfn_pte(args->pte_pfn, args->page_prot);Please keep this unchanged and move to its original position.
Ok.
#ifndef CONFIG_RISCV pte = __pte(pte_val(pte) | RANDOM_ORVALUE); #endif - set_pte_at(mm, vaddr, ptep, pte); + set_pte_at(args->mm, args->vaddr, args->ptep, pte); barrier(); - pte_clear(mm, vaddr, ptep); - pte = ptep_get(ptep); + pte_clear(args->mm, args->vaddr, args->ptep); + pte = ptep_get(args->ptep); WARN_ON(!pte_none(pte)); }@@ -1150,11 +1156,10 @@ static int __init debug_vm_pgtable(void)p4d_t *p4dp, *saved_p4dp; pud_t *pudp, *saved_pudp; pmd_t *pmdp, *saved_pmdp, pmd; - pte_t *ptep; pgtable_t saved_ptep; pgprot_t prot; phys_addr_t paddr; - unsigned long vaddr, pte_aligned, pmd_aligned; + unsigned long vaddr, pmd_aligned; unsigned long pud_aligned; spinlock_t *ptl = NULL; int idx, ret; @@ -1189,10 +1194,8 @@ static int __init debug_vm_pgtable(void) */ paddr = __pa_symbol(&start_kernel);- pte_aligned = (paddr & PAGE_MASK) >> PAGE_SHIFT;Please dont drop pte_aligned just yet.
We need to drop the variable. Otherwise, there is build warning to complain: 'unused variable'.
pmd_aligned = (paddr & PMD_MASK) >> PAGE_SHIFT; pud_aligned = (paddr & PUD_MASK) >> PAGE_SHIFT; - WARN_ON(!pfn_valid(pte_aligned));This should go into init_args() at the right place as the following, after evaluating it from 'start_kernel' symbol - just to be sure. WARN_ON(!pfn_valid(args->fixed_pte_pfn))
Yes.
pgdp = pgd_offset(mm, vaddr);p4dp = p4d_alloc(mm, pgdp, vaddr); @@ -1272,11 +1275,11 @@ static int __init debug_vm_pgtable(void) * Page table modifying tests. They need to hold * proper page table lock. */ - - ptep = pte_offset_map_lock(mm, pmdp, vaddr, &ptl); - pte_clear_tests(mm, ptep, pte_aligned, vaddr, prot); - pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot); - pte_unmap_unlock(ptep, ptl); + ptl = pte_lockptr(args.mm, args.pmdp); + spin_lock(ptl); + pte_clear_tests(&args); + pte_advanced_tests(&args); + spin_unlock(ptl);Why pte_offset_map_lock()/pte_unmap_unlock() has been dropped and spin_lock()/spin_unlock() sequence has been added ? Please dont change the tests in these patches.
The semantics of pte_offset_map_lock() is to grab and take the lock and return the PTE entry, which is mapped if needed. We already had the PTE entry tracked by args->ptep in init_args(). So some of the operations covered by pte_offset_map_lock() isn't needed any more.
ptl = pmd_lock(mm, pmdp);pmd_clear_tests(mm, pmdp);
Thanks, Gavin
