diff options
Diffstat (limited to 'tools/testing/vma')
| -rw-r--r-- | tools/testing/vma/vma.c | 3 | ||||
| -rw-r--r-- | tools/testing/vma/vma_internal.h | 49 |
2 files changed, 51 insertions, 1 deletions
diff --git a/tools/testing/vma/vma.c b/tools/testing/vma/vma.c index 656e1c75b711..fd37ce3b2628 100644 --- a/tools/testing/vma/vma.c +++ b/tools/testing/vma/vma.c @@ -339,6 +339,7 @@ static bool test_simple_modify(void) struct mm_struct mm = {}; struct vm_area_struct *init_vma = alloc_vma(&mm, 0, 0x3000, 0, vm_flags); VMA_ITERATOR(vmi, &mm, 0x1000); + vm_flags_t flags = VM_READ | VM_MAYREAD; ASSERT_FALSE(attach_vma(&mm, init_vma)); @@ -347,7 +348,7 @@ static bool test_simple_modify(void) * performs the merge/split only. */ vma = vma_modify_flags(&vmi, init_vma, init_vma, - 0x1000, 0x2000, VM_READ | VM_MAYREAD); + 0x1000, 0x2000, &flags); ASSERT_NE(vma, NULL); /* We modify the provided VMA, and on split allocate new VMAs. */ ASSERT_EQ(vma, init_vma); diff --git a/tools/testing/vma/vma_internal.h b/tools/testing/vma/vma_internal.h index 9f724954a0f6..f64064ee4858 100644 --- a/tools/testing/vma/vma_internal.h +++ b/tools/testing/vma/vma_internal.h @@ -56,6 +56,7 @@ extern unsigned long dac_mmap_min_addr; #define VM_MAYEXEC 0x00000040 #define VM_GROWSDOWN 0x00000100 #define VM_PFNMAP 0x00000400 +#define VM_MAYBE_GUARD 0x00000800 #define VM_LOCKED 0x00002000 #define VM_IO 0x00004000 #define VM_SEQ_READ 0x00008000 /* App will access data sequentially */ @@ -116,6 +117,54 @@ extern unsigned long dac_mmap_min_addr; #define VM_SEALED VM_NONE #endif +/* + * Flags which should be 'sticky' on merge - that is, flags which, when one VMA + * possesses it but the other does not, the merged VMA should nonetheless have + * applied to it: + * + * VM_SOFTDIRTY - if a VMA is marked soft-dirty, that is has not had its + * references cleared via /proc/$pid/clear_refs, any merged VMA + * should be considered soft-dirty also as it operates at a VMA + * granularity. + */ +#define VM_STICKY (VM_SOFTDIRTY | VM_MAYBE_GUARD) + +/* + * VMA flags we ignore for the purposes of merge, i.e. one VMA possessing one + * of these flags and the other not does not preclude a merge. + * + * VM_STICKY - When merging VMAs, VMA flags must match, unless they are + * 'sticky'. If any sticky flags exist in either VMA, we simply + * set all of them on the merged VMA. + */ +#define VM_IGNORE_MERGE VM_STICKY + +/* + * Flags which should result in page tables being copied on fork. These are + * flags which indicate that the VMA maps page tables which cannot be + * reconsistuted upon page fault, so necessitate page table copying upon + * + * VM_PFNMAP / VM_MIXEDMAP - These contain kernel-mapped data which cannot be + * reasonably reconstructed on page fault. + * + * VM_UFFD_WP - Encodes metadata about an installed uffd + * write protect handler, which cannot be + * reconstructed on page fault. + * + * We always copy pgtables when dst_vma has uffd-wp + * enabled even if it's file-backed + * (e.g. shmem). Because when uffd-wp is enabled, + * pgtable contains uffd-wp protection information, + * that's something we can't retrieve from page cache, + * and skip copying will lose those info. + * + * VM_MAYBE_GUARD - Could contain page guard region markers which + * by design are a property of the page tables + * only and thus cannot be reconstructed on page + * fault. + */ +#define VM_COPY_ON_FORK (VM_PFNMAP | VM_MIXEDMAP | VM_UFFD_WP | VM_MAYBE_GUARD) + #define FIRST_USER_ADDRESS 0UL #define USER_PGTABLES_CEILING 0UL |