88 lines
2.2 KiB
C
88 lines
2.2 KiB
C
|
/* 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;
|
||
|
|
|
||
|
|
/* 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;
|
||
|
|
}
|
||
|
|
|
||
|
|
return pfn_valid(x >> PAGE_SHIFT);
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* !MODULE */
|
||
|
|
|
||
|
|
#endif /* _ASM_X86_KMSAN_H */
|