linux/arch/arm/mm/fault.h
Wang Kefeng abc25bbcb5 ARM: 9131/1: mm: Fix PXN process with LPAE feature
When user code execution with privilege mode, it will lead to
infinite loop in the page fault handler if ARM_LPAE enabled,

The issue could be reproduced with
  "echo EXEC_USERSPACE > /sys/kernel/debug/provoke-crash/DIRECT"

As Permission fault shows in ARM spec,
  IFSR format when using the Short-descriptor translation table format
    Permission fault:       01101 First level      01111 Second level
  IFSR format when using the Long-descriptor translation table format
    Permission fault:       0011LL LL bits indicate levelb.

Add is_permission_fault() function to check permission fault and die
if permission fault occurred under instruction fault in do_page_fault().

Fixes: 1d4d37159d ("ARM: 8235/1: Support for the PXN CPU feature on ARMv7")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2021-10-19 10:35:43 +01:00

39 lines
862 B
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ARCH_ARM_FAULT_H
#define __ARCH_ARM_FAULT_H
/*
* Fault status register encodings. We steal bit 31 for our own purposes.
*/
#define FSR_LNX_PF (1 << 31)
#define FSR_CM (1 << 13)
#define FSR_WRITE (1 << 11)
#define FSR_FS4 (1 << 10)
#define FSR_FS3_0 (15)
#define FSR_FS5_0 (0x3f)
#ifdef CONFIG_ARM_LPAE
#define FSR_FS_AEA 17
#define FS_PERM_NOLL 0xC
#define FS_PERM_NOLL_MASK 0x3C
static inline int fsr_fs(unsigned int fsr)
{
return fsr & FSR_FS5_0;
}
#else
#define FSR_FS_AEA 22
#define FS_L1_PERM 0xD
#define FS_L2_PERM 0xF
static inline int fsr_fs(unsigned int fsr)
{
return (fsr & FSR_FS3_0) | (fsr & FSR_FS4) >> 6;
}
#endif
void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs);
void early_abt_enable(void);
#endif /* __ARCH_ARM_FAULT_H */