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mman: allow CoW to fork pages when accessing from kernel

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Mark
2020-09-01 23:47:03 +03:00
parent 2ff4dca8c4
commit 158c181c54
1 changed files with 14 additions and 1 deletions
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arch/amd64/hw/exc.c
+14 -1
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@@ -57,7 +57,9 @@ int do_pfault(struct amd64_exception_frame *frame, uintptr_t cr2, uintptr_t cr3)
return -1;
}
if (frame->cs == 0x23 && cr2 < KERNEL_VIRT_BASE) {
if (cr2 < KERNEL_VIRT_BASE) {
// TODO: was that user CS check necessary?
// Userspace fault
uint64_t flags;
uintptr_t phys = mm_map_get(space, cr2 & MM_PAGE_MASK, &flags);
@@ -123,6 +125,17 @@ static void exc_dump(int level, struct amd64_exception_frame *frame) {
}
debugf(level, "Fault address: %p\n", cr2);
uintptr_t phys = mm_map_get((mm_space_t) MM_VIRTUALIZE(cr3), cr2 & MM_PAGE_MASK, NULL);
if (phys == MM_NADDR) {
debugf(level, "Has no physical address (non-present?)\n");
} else {
debugf(level, "Refers to phys %p\n", phys);
struct page *page = PHYS2PAGE(phys);
kdebug(" Refcount: %u\n", page->refcount);
kdebug(" Usage: %u\n", page->usage);
}
if (frame->exc_code & X86_PF_RESVD) {
debugf(level, " - Page structure has reserved bit set\n");
}