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| author | Idan Horowitz <idan.horowitz@gmail.com> | 2022-03-22 13:34:40 +0200 |
|---|---|---|
| committer | Andreas Kling <kling@serenityos.org> | 2022-03-22 16:46:51 +0100 |
| commit | d850e483f7b23b848ed6f04befc3fa9f3da98893 (patch) | |
| tree | 7533b86bfe0da38528ea4fe28ac4eaced64d0ece | |
| parent | 025cfacd46ac7509d1d3e645bc302b33ca23624f (diff) | |
| download | serenity-d850e483f7b23b848ed6f04befc3fa9f3da98893.zip | |
Kernel: Keep kernel base load address 2 MiB aligned
This requirement comes from the fact the Prekernel mapping logic only
uses 2 MiB pages.
This unfortunately reduces the bits of entropy in kernel addresses from
16 bits to 7, but it could be further improved in the future by making
the Prekernel mapping logic a bit more dynamic.
| -rw-r--r-- | Kernel/Prekernel/init.cpp | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/Kernel/Prekernel/init.cpp b/Kernel/Prekernel/init.cpp index ef55299346..9fced041a2 100644 --- a/Kernel/Prekernel/init.cpp +++ b/Kernel/Prekernel/init.cpp @@ -91,17 +91,15 @@ extern "C" [[noreturn]] void init() FlatPtr kernel_physical_base = 0x200000; #if ARCH(I386) - FlatPtr kernel_load_base = 0xc0200000; + FlatPtr default_kernel_load_base = 0xc0200000; #else - FlatPtr kernel_load_base = 0x2000200000; + FlatPtr default_kernel_load_base = 0x2000200000; #endif -#if ARCH(X86_64) // KASLR static constexpr auto maximum_offset = 256 * MiB; - kernel_load_base = kernel_load_base + (generate_secure_seed() % maximum_offset); - kernel_load_base = kernel_load_base & ~(PAGE_SIZE - 1); -#endif + FlatPtr kernel_load_base = default_kernel_load_base + (generate_secure_seed() % maximum_offset); + kernel_load_base &= ~(2 * MiB - 1); FlatPtr kernel_load_end = 0; for (size_t i = 0; i < kernel_elf_header.e_phnum; i++) { |