diff options
Diffstat (limited to 'mm/debug_vm_pgtable.c')
| -rw-r--r-- | mm/debug_vm_pgtable.c | 102 |
1 files changed, 83 insertions, 19 deletions
diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index c631ade3f1d2..bb3328f46126 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -15,6 +15,7 @@ #include <linux/hugetlb.h> #include <linux/kernel.h> #include <linux/kconfig.h> +#include <linux/memblock.h> #include <linux/mm.h> #include <linux/mman.h> #include <linux/mm_types.h> @@ -80,6 +81,7 @@ struct pgtable_debug_args { unsigned long pmd_pfn; unsigned long pte_pfn; + unsigned long fixed_alignment; unsigned long fixed_pgd_pfn; unsigned long fixed_p4d_pfn; unsigned long fixed_pud_pfn; @@ -430,7 +432,8 @@ static void __init pmd_huge_tests(struct pgtable_debug_args *args) { pmd_t pmd; - if (!arch_vmap_pmd_supported(args->page_prot)) + if (!arch_vmap_pmd_supported(args->page_prot) || + args->fixed_alignment < PMD_SIZE) return; pr_debug("Validating PMD huge\n"); @@ -449,7 +452,8 @@ static void __init pud_huge_tests(struct pgtable_debug_args *args) { pud_t pud; - if (!arch_vmap_pud_supported(args->page_prot)) + if (!arch_vmap_pud_supported(args->page_prot) || + args->fixed_alignment < PUD_SIZE) return; pr_debug("Validating PUD huge\n"); @@ -1077,10 +1081,85 @@ debug_vm_pgtable_alloc_huge_page(struct pgtable_debug_args *args, int order) return page; } +/* + * Check if a physical memory range described by <pstart, pend> contains + * an area that is of size psize, and aligned to psize. + * + * Don't use address 0, an all-zeroes physical address might mask bugs, and + * it's not used on x86. + */ +static void __init phys_align_check(phys_addr_t pstart, + phys_addr_t pend, unsigned long psize, + phys_addr_t *physp, unsigned long *alignp) +{ + phys_addr_t aligned_start, aligned_end; + + if (pstart == 0) + pstart = PAGE_SIZE; + + aligned_start = ALIGN(pstart, psize); + aligned_end = aligned_start + psize; + + if (aligned_end > aligned_start && aligned_end <= pend) { + *alignp = psize; + *physp = aligned_start; + } +} + +static void __init init_fixed_pfns(struct pgtable_debug_args *args) +{ + u64 idx; + phys_addr_t phys, pstart, pend; + + /* + * Initialize the fixed pfns. To do this, try to find a + * valid physical range, preferably aligned to PUD_SIZE, + * but settling for aligned to PMD_SIZE as a fallback. If + * neither of those is found, use the physical address of + * the start_kernel symbol. + * + * The memory doesn't need to be allocated, it just needs to exist + * as usable memory. It won't be touched. + * + * The alignment is recorded, and can be checked to see if we + * can run the tests that require an actual valid physical + * address range on some architectures ({pmd,pud}_huge_test + * on x86). + */ + + phys = __pa_symbol(&start_kernel); + args->fixed_alignment = PAGE_SIZE; + + for_each_mem_range(idx, &pstart, &pend) { + /* First check for a PUD-aligned area */ + phys_align_check(pstart, pend, PUD_SIZE, &phys, + &args->fixed_alignment); + + /* If a PUD-aligned area is found, we're done */ + if (args->fixed_alignment == PUD_SIZE) + break; + + /* + * If no PMD-aligned area found yet, check for one, + * but continue the loop to look for a PUD-aligned area. + */ + if (args->fixed_alignment < PMD_SIZE) + phys_align_check(pstart, pend, PMD_SIZE, &phys, + &args->fixed_alignment); + } + + args->fixed_pgd_pfn = __phys_to_pfn(phys & PGDIR_MASK); + args->fixed_p4d_pfn = __phys_to_pfn(phys & P4D_MASK); + args->fixed_pud_pfn = __phys_to_pfn(phys & PUD_MASK); + args->fixed_pmd_pfn = __phys_to_pfn(phys & PMD_MASK); + args->fixed_pte_pfn = __phys_to_pfn(phys & PAGE_MASK); + WARN_ON(!pfn_valid(args->fixed_pte_pfn)); +} + + static int __init init_args(struct pgtable_debug_args *args) { struct page *page = NULL; - phys_addr_t phys; int ret = 0; /* @@ -1160,22 +1239,7 @@ static int __init init_args(struct pgtable_debug_args *args) args->start_ptep = pmd_pgtable(READ_ONCE(*args->pmdp)); WARN_ON(!args->start_ptep); - /* - * PFN for mapping at PTE level is determined from a standard kernel - * text symbol. But pfns for higher page table levels are derived by - * masking lower bits of this real pfn. These derived pfns might not - * exist on the platform but that does not really matter as pfn_pxx() - * helpers will still create appropriate entries for the test. This - * helps avoid large memory block allocations to be used for mapping - * at higher page table levels in some of the tests. - */ - phys = __pa_symbol(&start_kernel); - args->fixed_pgd_pfn = __phys_to_pfn(phys & PGDIR_MASK); - args->fixed_p4d_pfn = __phys_to_pfn(phys & P4D_MASK); - args->fixed_pud_pfn = __phys_to_pfn(phys & PUD_MASK); - args->fixed_pmd_pfn = __phys_to_pfn(phys & PMD_MASK); - args->fixed_pte_pfn = __phys_to_pfn(phys & PAGE_MASK); - WARN_ON(!pfn_valid(args->fixed_pte_pfn)); + init_fixed_pfns(args); /* * Allocate (huge) pages because some of the tests need to access |