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Ryan Houdek
0f54369f9b
This is an interesting vdso implementation because it only exists in x86-64 with kernel v6.11. For Arm64 the implementation is likely to land in a couple kernel versions from now. Some differences with vdso_getrandom versus the regular getrandom syscall - Has two additional arguments, opaque_state and opaque_len - Expects the userspace to mmap/munmap this opaque state structure - Lets userspace query information about this structure upfront - If the opaque data structure isn't provided then it falls back to regular SYS_getrandom With the "glibc" implementation, we can tell the interface to allocate a single page that gets unused (otherwise glibc ends up not using the interface), and fallback to the regular SYS_getrandom. In the case of the vdso interface, currently the arguments just get passed through. Keeping this as a WIP until the ARM64 kernel patches land and I can actually test the things. Running the "glibc" path works today with the selftest, but the vdso path is currently completely untested.
29 lines
839 B
C++
29 lines
839 B
C++
// SPDX-License-Identifier: MIT
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#pragma once
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#include <FEXCore/IR/IR.h>
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#include <FEXCore/fextl/vector.h>
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#include "LinuxSyscalls/Syscalls.h"
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namespace FEX::VDSO {
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using MapperFn = std::function<void*(void* addr, size_t length, int prot, int flags, int fd, off_t offset)>;
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struct VDSOMapping {
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void* VDSOBase {};
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size_t VDSOSize {};
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void* OptionalSigReturnMapping {};
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size_t OptionalMappingSize {};
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};
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struct VDSOSigReturn {
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void* VDSO_kernel_sigreturn;
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void* VDSO_kernel_rt_sigreturn;
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};
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VDSOMapping LoadVDSOThunks(bool Is64Bit, FEX::HLE::SyscallHandler* const Handler);
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void UnloadVDSOMapping(const VDSOMapping& Mapping);
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uint64_t GetVSyscallEntry(const void* VDSOBase);
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const std::span<FEXCore::IR::ThunkDefinition> GetVDSOThunkDefinitions(bool Is64Bit);
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const VDSOSigReturn& GetVDSOSymbols();
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} // namespace FEX::VDSO
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