Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
Alexander Potapenko | 293 | 95.13% | 3 | 75.00% |
Marco Elver | 15 | 4.87% | 1 | 25.00% |
Total | 308 | 4 |
/* SPDX-License-Identifier: GPL-2.0 */ /* * x86 KMSAN support. * * Copyright (C) 2022, Google LLC * Author: Alexander Potapenko <glider@google.com> */ #ifndef _ASM_X86_KMSAN_H #define _ASM_X86_KMSAN_H #ifndef MODULE #include <asm/cpu_entry_area.h> #include <asm/processor.h> #include <linux/mmzone.h> DECLARE_PER_CPU(char[CPU_ENTRY_AREA_SIZE], cpu_entry_area_shadow); DECLARE_PER_CPU(char[CPU_ENTRY_AREA_SIZE], cpu_entry_area_origin); /* * Functions below are declared in the header to make sure they are inlined. * They all are called from kmsan_get_metadata() for every memory access in * the kernel, so speed is important here. */ /* * Compute metadata addresses for the CPU entry area on x86. */ static inline void *arch_kmsan_get_meta_or_null(void *addr, bool is_origin) { unsigned long addr64 = (unsigned long)addr; char *metadata_array; unsigned long off; int cpu; if ((addr64 < CPU_ENTRY_AREA_BASE) || (addr64 >= (CPU_ENTRY_AREA_BASE + CPU_ENTRY_AREA_MAP_SIZE))) return NULL; cpu = (addr64 - CPU_ENTRY_AREA_BASE) / CPU_ENTRY_AREA_SIZE; off = addr64 - (unsigned long)get_cpu_entry_area(cpu); if ((off < 0) || (off >= CPU_ENTRY_AREA_SIZE)) return NULL; metadata_array = is_origin ? cpu_entry_area_origin : cpu_entry_area_shadow; return &per_cpu(metadata_array[off], cpu); } /* * Taken from arch/x86/mm/physaddr.h to avoid using an instrumented version. */ static inline bool kmsan_phys_addr_valid(unsigned long addr) { if (IS_ENABLED(CONFIG_PHYS_ADDR_T_64BIT)) return !(addr >> boot_cpu_data.x86_phys_bits); else return true; } /* * Taken from arch/x86/mm/physaddr.c to avoid using an instrumented version. */ static inline bool kmsan_virt_addr_valid(void *addr) { unsigned long x = (unsigned long)addr; unsigned long y = x - __START_KERNEL_map; bool ret; /* use the carry flag to determine if x was < __START_KERNEL_map */ if (unlikely(x > y)) { x = y + phys_base; if (y >= KERNEL_IMAGE_SIZE) return false; } else { x = y + (__START_KERNEL_map - PAGE_OFFSET); /* carry flag will be set if starting x was >= PAGE_OFFSET */ if ((x > y) || !kmsan_phys_addr_valid(x)) return false; } /* * pfn_valid() relies on RCU, and may call into the scheduler on exiting * the critical section. However, this would result in recursion with * KMSAN. Therefore, disable preemption here, and re-enable preemption * below while suppressing reschedules to avoid recursion. * * Note, this sacrifices occasionally breaking scheduling guarantees. * Although, a kernel compiled with KMSAN has already given up on any * performance guarantees due to being heavily instrumented. */ preempt_disable(); ret = pfn_valid(x >> PAGE_SHIFT); preempt_enable_no_resched(); return ret; } #endif /* !MODULE */ #endif /* _ASM_X86_KMSAN_H */
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with Cregit http://github.com/cregit/cregit
Version 2.0-RC1