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https://github.com/RGBCube/serenity
synced 2025-07-26 07:47:37 +00:00
Add basic zero faults.
mmap() will now map uncommitted pages that get allocated and zeroed upon the first access. I also made /proc/PID/vm show number of "committed" bytes in each region. This is so cool! :^)
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parent
e88f306d07
commit
629c5be10b
5 changed files with 42 additions and 7 deletions
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@ -224,6 +224,24 @@ Region* MemoryManager::region_from_laddr(Process& process, LinearAddress laddr)
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return nullptr;
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}
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bool MemoryManager::zero_page(PageDirectory& page_directory, Region& region, unsigned page_index_in_region)
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{
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ASSERT_INTERRUPTS_DISABLED();
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auto& vmo = region.vmo();
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auto physical_page = allocate_physical_page();
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byte* dest_ptr = quickmap_page(*physical_page);
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memset(dest_ptr, 0, PAGE_SIZE);
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#ifdef PAGE_FAULT_DEBUG
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dbgprintf(" >> ZERO P%x\n", physical_page->paddr().get());
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#endif
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unquickmap_page();
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region.cow_map.set(page_index_in_region, false);
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vmo.physical_pages()[page_index_in_region] = move(physical_page);
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unquickmap_page();
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remap_region_page(&page_directory, region, page_index_in_region, true);
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return true;
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}
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bool MemoryManager::copy_on_write(Process& process, Region& region, unsigned page_index_in_region)
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{
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ASSERT_INTERRUPTS_DISABLED();
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@ -325,7 +343,9 @@ PageFaultResponse MemoryManager::handle_page_fault(const PageFault& fault)
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page_in_from_vnode(*current->m_page_directory, *region, page_index_in_region);
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return PageFaultResponse::Continue;
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} else {
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kprintf("NP(error) fault in Region{%p}[%u]\n", region, page_index_in_region);
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dbgprintf("NP(zero) fault in Region{%p}[%u]\n", region, page_index_in_region);
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zero_page(*current->m_page_directory, *region, page_index_in_region);
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return PageFaultResponse::Continue;
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}
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} else if (fault.is_protection_violation()) {
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if (region->cow_map.get(page_index_in_region)) {
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@ -761,3 +781,13 @@ inline bool PageDirectory::is_active() const
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{
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return ¤t->page_directory() == this;
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}
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size_t Region::committed() const
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{
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size_t bytes = 0;
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for (size_t i = 0; i < page_count(); ++i) {
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if (m_vmo->physical_pages()[first_page_index() + i])
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bytes += PAGE_SIZE;
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}
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return bytes;
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}
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@ -132,6 +132,8 @@ public:
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int commit(Process&);
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int decommit(Process&);
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size_t committed() const;
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LinearAddress linearAddress;
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size_t size { 0 };
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size_t m_offset_in_vmo { 0 };
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@ -209,6 +211,7 @@ private:
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bool copy_on_write(Process&, Region&, unsigned page_index_in_region);
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bool page_in_from_vnode(PageDirectory&, Region&, unsigned page_index_in_region);
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bool zero_page(PageDirectory&, Region& region, unsigned page_index_in_region);
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byte* quickmap_page(PhysicalPage&);
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void unquickmap_page();
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@ -52,12 +52,13 @@ ByteBuffer procfs$pid_vm(Process& process)
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auto stringImpl = StringImpl::createUninitialized(80 + process.regionCount() * 160 + 4096, buffer);
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memset(buffer, 0, stringImpl->length());
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char* ptr = buffer;
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ptr += ksprintf(ptr, "BEGIN END SIZE NAME\n");
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ptr += ksprintf(ptr, "BEGIN END SIZE COMMIT NAME\n");
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for (auto& region : process.regions()) {
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ptr += ksprintf(ptr, "%x -- %x %x %s\n",
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ptr += ksprintf(ptr, "%x -- %x %x %x %s\n",
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region->linearAddress.get(),
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region->linearAddress.offset(region->size - 1).get(),
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region->size,
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region->committed(),
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region->name.characters());
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}
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*ptr = '\0';
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@ -65,7 +65,7 @@ Vector<Process*> Process::allProcesses()
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return processes;
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}
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Region* Process::allocate_region(LinearAddress laddr, size_t size, String&& name, bool is_readable, bool is_writable)
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Region* Process::allocate_region(LinearAddress laddr, size_t size, String&& name, bool is_readable, bool is_writable, bool commit)
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{
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// FIXME: This needs sanity checks. What if this overlaps existing regions?
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if (laddr.is_null()) {
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@ -74,6 +74,7 @@ Region* Process::allocate_region(LinearAddress laddr, size_t size, String&& name
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}
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laddr.mask(0xfffff000);
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m_regions.append(adopt(*new Region(laddr, size, move(name), is_readable, is_writable)));
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if (commit)
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m_regions.last()->commit(*this);
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MM.mapRegion(*this, *m_regions.last());
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return m_regions.last().ptr();
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@ -161,7 +162,7 @@ void* Process::sys$mmap(const Syscall::SC_mmap_params* params)
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InterruptDisabler disabler;
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// FIXME: Implement mapping at a client-specified address. Most of the support is already in plcae.
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ASSERT(addr == nullptr);
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auto* region = allocate_region(LinearAddress(), size, "mmap", prot & PROT_READ, prot & PROT_WRITE);
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auto* region = allocate_region(LinearAddress(), size, "mmap", prot & PROT_READ, prot & PROT_WRITE, false);
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if (!region)
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return (void*)-ENOMEM;
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return region->linearAddress.asPtr();
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@ -283,7 +283,7 @@ private:
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TTY* m_tty { nullptr };
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Region* allocate_region(LinearAddress, size_t, String&& name, bool is_readable = true, bool is_writable = true);
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Region* allocate_region(LinearAddress, size_t, String&& name, bool is_readable = true, bool is_writable = true, bool commit = true);
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Region* allocate_file_backed_region(LinearAddress, size_t, RetainPtr<Vnode>&& vnode, String&& name, bool is_readable, bool is_writable);
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Region* allocate_region_with_vmo(LinearAddress, size_t, RetainPtr<VMObject>&&, size_t offset_in_vmo, String&& name, bool is_readable, bool is_writable);
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bool deallocate_region(Region& region);
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