unsigned long vaddr = (unsigned long)unsafe_src;
/*
- * Range covering the highest possible canonical userspace address
- * as well as non-canonical address range. For the canonical range
- * we also need to include the userspace guard page.
+ * Do not allow userspace addresses. This disallows
+ * normal userspace and the userspace guard page:
*/
- return vaddr >= TASK_SIZE_MAX + PAGE_SIZE &&
- __is_canonical_address(vaddr, boot_cpu_data.x86_virt_bits);
+ if (vaddr < TASK_SIZE_MAX + PAGE_SIZE)
+ return false;
+
+ /*
+ * Allow everything during early boot before 'x86_virt_bits'
+ * is initialized. Needed for instruction decoding in early
+ * exception handlers.
+ */
+ if (!boot_cpu_data.x86_virt_bits)
+ return true;
+
+ return __is_canonical_address(vaddr, boot_cpu_data.x86_virt_bits);
}
#else
bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size)