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| author | Andrew Kaster <akaster@serenityos.org> | 2021-07-06 20:25:22 -0600 |
|---|---|---|
| committer | Andreas Kling <kling@serenityos.org> | 2021-07-11 19:42:00 +0200 |
| commit | 578d45b480c5b167df916ebc42e13bc1bd6153c1 (patch) | |
| tree | 76a48cbf6eefd12ca746b4d88b3cc07e8712a97a | |
| parent | ab196b484a4b901886c449f9eebb5e8c8efa290a (diff) | |
| download | serenity-578d45b480c5b167df916ebc42e13bc1bd6153c1.zip | |
Kernel: Create and use USER_RANGE_CEILING
We had an inconsistency in valid user addresses. is_user_range() was
checking against the kernel base address, but previous changes caused
the maximum valid user addressable range to be 32 MiB below that.
This patch stops mmap(MAP_FIXED) of a range between these two bounds
from panic-ing the kernel in RangeAllocator::allocate_specific.
| -rw-r--r-- | Kernel/Sections.h | 2 | ||||
| -rw-r--r-- | Kernel/VM/MemoryManager.h | 2 | ||||
| -rw-r--r-- | Kernel/VM/PageDirectory.cpp | 2 |
3 files changed, 4 insertions, 2 deletions
diff --git a/Kernel/Sections.h b/Kernel/Sections.h index dede1e7462..61b5d57e29 100644 --- a/Kernel/Sections.h +++ b/Kernel/Sections.h @@ -19,3 +19,5 @@ #define KERNEL_QUICKMAP_PD (KERNEL_PT1024_BASE + 0x7000) #define KERNEL_QUICKMAP_PER_CPU_BASE (KERNEL_PT1024_BASE + 0x8000) #define KERNEL_PHYSICAL_PAGES_BASE (KERNEL_BASE + KERNEL_PD_OFFSET) + +#define USER_RANGE_CEILING 0xBE000000 diff --git a/Kernel/VM/MemoryManager.h b/Kernel/VM/MemoryManager.h index 2be1fb9db8..16d695e7c2 100644 --- a/Kernel/VM/MemoryManager.h +++ b/Kernel/VM/MemoryManager.h @@ -278,7 +278,7 @@ void VMObject::for_each_region(Callback callback) inline bool is_user_address(VirtualAddress vaddr) { - return vaddr.get() < KERNEL_BASE; + return vaddr.get() < USER_RANGE_CEILING; } inline bool is_user_range(VirtualAddress vaddr, size_t size) diff --git a/Kernel/VM/PageDirectory.cpp b/Kernel/VM/PageDirectory.cpp index 3fd515697f..08897da286 100644 --- a/Kernel/VM/PageDirectory.cpp +++ b/Kernel/VM/PageDirectory.cpp @@ -63,7 +63,7 @@ UNMAP_AFTER_INIT void PageDirectory::allocate_kernel_directory() PageDirectory::PageDirectory(const RangeAllocator* parent_range_allocator) { constexpr FlatPtr userspace_range_base = 0x00800000; - constexpr FlatPtr userspace_range_ceiling = 0xbe000000; + constexpr FlatPtr userspace_range_ceiling = USER_RANGE_CEILING; ScopedSpinLock lock(s_mm_lock); if (parent_range_allocator) { |