From 1039bffd6ae9c75b42b7d148d6c1106134107b66 Mon Sep 17 00:00:00 2001 From: Xie Yuanbin Date: Tue, 28 Jul 2026 03:16:42 +0100 Subject: ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults When CONFIG_DEBUG_USER=y, and cmdline "user_debug=31" is set, a user fault may trigger show_pte() without any lock. If another thread in the same process concurrently calls munmap(), the page table pages may be freed while show_pte() is still traversing them, causing a use-after-free in show_pte(). If CONFIG_ARM_LPAE=y, this may cause a kernel panic if the pages table of PMD are freed when show_pte() is running. Acquire mmap_write_lock() around show_pte() for user faults to fix the contention. For user faults, additionally restrict that show_pte() is called only when the addr is a user-space address (addr < TASK_SIZE). This is because the lock of tsk->mm only protects the virtual memory of user address space, furthermore, dumping the page tables of a kernel-space address for user faults is unnecessary and may have security implications. Keep everything unchanged for kernel faults, because the kernel is already in the "oops" state, acquiring a lock may risk a deadlock. Co-developed-by: Qi Xi Fixes: 6d021b724481 ("ARM: dump pgd, pmd and pte states on unhandled data abort faults") Link: https://lore.kernel.org/20260716014022.2823-1-xieyuanbin1@huawei.com Acked-by: Lorenzo Stoakes (ARM) Reviewed-by: Linus Walleij Signed-off-by: Qi Xi Signed-off-by: Xie Yuanbin Signed-off-by: Russell King --- include/soc/microchip/mpfs.h | 54 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 include/soc/microchip/mpfs.h (limited to 'include/soc/microchip') diff --git a/include/soc/microchip/mpfs.h b/include/soc/microchip/mpfs.h new file mode 100644 index 000000000..ec04c98a8 --- /dev/null +++ b/include/soc/microchip/mpfs.h @@ -0,0 +1,54 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * + * Microchip PolarFire SoC (MPFS) + * + * Copyright (c) 2020 Microchip Corporation. All rights reserved. + * + * Author: Conor Dooley + * + */ + +#ifndef __SOC_MPFS_H__ +#define __SOC_MPFS_H__ + +#include +#include +#include + +struct mpfs_sys_controller; + +struct mpfs_mss_msg { + u8 cmd_opcode; + u16 cmd_data_size; + struct mpfs_mss_response *response; + u8 *cmd_data; + u16 mbox_offset; + u16 resp_offset; +}; + +struct mpfs_mss_response { + u32 resp_status; + u32 *resp_msg; + u16 resp_size; +}; + +#if IS_ENABLED(CONFIG_POLARFIRE_SOC_SYS_CTRL) + +int mpfs_blocking_transaction(struct mpfs_sys_controller *mpfs_client, struct mpfs_mss_msg *msg); + +struct mpfs_sys_controller *mpfs_sys_controller_get(struct device *dev); + +struct mtd_info *mpfs_sys_controller_get_flash(struct mpfs_sys_controller *mpfs_client); + +#endif /* if IS_ENABLED(CONFIG_POLARFIRE_SOC_SYS_CTRL) */ + +#if IS_ENABLED(CONFIG_MCHP_CLK_MPFS) +#if IS_ENABLED(CONFIG_RESET_POLARFIRE_SOC) +int mpfs_reset_controller_register(struct device *clk_dev, struct regmap *map); +#else +static inline int mpfs_reset_controller_register(struct device *clk_dev, void __iomem *base) { return 0; } +#endif /* if IS_ENABLED(CONFIG_RESET_POLARFIRE_SOC) */ +#endif /* if IS_ENABLED(CONFIG_MCHP_CLK_MPFS) */ + +#endif /* __SOC_MPFS_H__ */ -- cgit v1.3.1