From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- arch/x86/mm/maccess.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 arch/x86/mm/maccess.c (limited to 'arch/x86/mm/maccess.c') diff --git a/arch/x86/mm/maccess.c b/arch/x86/mm/maccess.c new file mode 100644 index 000000000..6993f026a --- /dev/null +++ b/arch/x86/mm/maccess.c @@ -0,0 +1,33 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include +#include + +#ifdef CONFIG_X86_64 +bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size) +{ + unsigned long vaddr = (unsigned long)unsafe_src; + + /* + * Do not allow userspace addresses. This disallows + * normal userspace and the userspace guard page: + */ + 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) +{ + return (unsigned long)unsafe_src >= TASK_SIZE_MAX; +} +#endif -- cgit v1.2.3