feat(process): 添加对fs/gs的用户空间地址验证

[fslongjin]

• 在ARCH_SET_FS和ARCH_SET_GS系统调用中添加FS/GS地址的用户空间验证
• 在进程克隆时添加TLS地址的用户空间验证
• 新增KernelCloneArgs::verify()方法用于验证克隆参数

[Copilot]

Pull Request Overview

This PR enables fork test support and adds address validation for thread-local storage (TLS) and segment base addresses. The changes improve security by verifying user-space addresses before they are used in clone operations and arch_prctl syscalls.

• Enabled fork_test in the gvisor test whitelist with an associated blocklist
• Added TLS address validation in KernelCloneArgs::verify()
• Added address validation for FS/GS base registers in arch_prctl syscall
• Modified process cleanup to ignore errors when unregistering from procfs

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
user/apps/tests/syscall/gvisor/whitelist.txt	Enabled fork_test in the test suite
user/apps/tests/syscall/gvisor/blocklists/fork_test	Added blocklist for fork test cases that are known to fail
kernel/src/process/syscall/clone_utils.rs	Added verification call before processing clone arguments
kernel/src/process/mod.rs	Changed procfs unregistration to ignore errors during cleanup
kernel/src/process/fork.rs	Added verify method to validate TLS address and moved verification before PCB creation
kernel/src/arch/x86_64/process/syscall.rs	Added address validation for FS and GS base addresses in arch_prctl

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