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-rw-r--r--kernel/uaccess.cc53
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diff --git a/kernel/uaccess.cc b/kernel/uaccess.cc
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--- a/kernel/uaccess.cc
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-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/* Copyright (C) 2026 Richard Qin */
-
-/*
- * User-Kernel Memory Copy — Phase 3 (Exception Tables)
- *
- * Validates user pointers by checking they fall within user address space
- * (below KERNEL_VA_BASE). Uses assembly-level safe copy functions that
- * integrate with the kernel's Exception Table mechanism.
- *
- * Reference: docs/specs/syscall.md §8
- */
-
-#include <lume/uaccess.h>
-#include <lume/task.h>
-#include <lume/errno.h>
-#include <lume/config.h>
-#include <lume/mm_layout.h>
-
-extern "C" int __uaccess_memcpy(void* dst, const void* src, uint64 len);
-extern "C" int64 __uaccess_strncpy(char* dst, const char* src, uint64 max_len);
-
-int copy_from_user(void* kernel_dst, uint64 user_src, uint64 len)
-{
- if (len == 0) return 0;
- if (!is_user_range(user_src, len)) return -EFAULT;
-
- return __uaccess_memcpy(kernel_dst, reinterpret_cast<const void*>(user_src), len);
-}
-
-int copy_to_user(uint64 user_dst, const void* kernel_src, uint64 len)
-{
- if (len == 0) return 0;
- if (!is_user_range(user_dst, len)) return -EFAULT;
-
- return __uaccess_memcpy(reinterpret_cast<void*>(user_dst), kernel_src, len);
-}
-
-int64 strncpy_from_user(char* kernel_dst, uint64 user_src, uint64 max_len)
-{
- if (!is_user_range(user_src, 1)) return -EFAULT;
-
- /* We must also check that the string does not cross into kernel space.
- This is safely handled by the assembly routine which will fault if it hits
- an unmapped page. However, to strictly respect kKernelVaBase, we should
- restrict max_len to the distance to kKernelVaBase. */
- uint64 max_allowed = kKernelVaBase - user_src;
- if (max_len > max_allowed) {
- max_len = max_allowed;
- }
-
- return __uaccess_strncpy(kernel_dst, reinterpret_cast<const char*>(user_src), max_len);
-}