/* * Based on arch/arm/include/asm/uaccess.h * * Copyright (C) 2012 ARM Ltd. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . */ #ifndef __ASM_UACCESS_H #define __ASM_UACCESS_H #include #include #include /* * User space memory access functions */ #include #include #include #include #include #include #include #include #define KERNEL_DS (-1UL) #define get_ds() (KERNEL_DS) #define USER_DS TASK_SIZE_64 #define get_fs() (current_thread_info()->addr_limit) static inline void set_fs(mm_segment_t fs) { current_thread_info()->addr_limit = fs; /* * Enable/disable UAO so that copy_to_user() etc can access * kernel memory with the unprivileged instructions. */ if (IS_ENABLED(CONFIG_ARM64_UAO) && fs == KERNEL_DS) asm(ALTERNATIVE("nop", SET_PSTATE_UAO(1), ARM64_HAS_UAO)); else asm(ALTERNATIVE("nop", SET_PSTATE_UAO(0), ARM64_HAS_UAO, CONFIG_ARM64_UAO)); } #define segment_eq(a, b) ((a) == (b)) /* * Test whether a block of memory is a valid user space address. * Returns 1 if the range is valid, 0 otherwise. * * This is equivalent to the following test: * (u65)addr + (u65)size <= current->addr_limit * * This needs 65-bit arithmetic. */ #define __range_ok(addr, size) \ ({ \ unsigned long flag, roksum; \ __chk_user_ptr(addr); \ asm("adds %1, %1, %3; ccmp %1, %4, #2, cc; cset %0, ls" \ : "=&r" (flag), "=&r" (roksum) \ : "1" (addr), "Ir" (size), \ "r" (current_thread_info()->addr_limit) \ : "cc"); \ flag; \ }) /* * When dealing with data aborts or instruction traps we may end up with * a tagged userland pointer. Clear the tag to get a sane pointer to pass * on to access_ok(), for instance. */ #define untagged_addr(addr) sign_extend64(addr, 55) #define access_ok(type, addr, size) __range_ok(addr, size) #define user_addr_max get_fs #define _ASM_EXTABLE(from, to) \ " .pushsection __ex_table, \"a\"\n" \ " .align 3\n" \ " .long (" #from " - .), (" #to " - .)\n" \ " .popsection\n" /* * User access enabling/disabling. */ #ifdef CONFIG_ARM64_SW_TTBR0_PAN static inline void __uaccess_ttbr0_disable(void) { unsigned long ttbr; /* reserved_ttbr0 placed at the end of swapper_pg_dir */ ttbr = read_sysreg(ttbr1_el1) + SWAPPER_DIR_SIZE; write_sysreg(ttbr, ttbr0_el1); isb(); } static inline void __uaccess_ttbr0_enable(void) { unsigned long flags; /* * Disable interrupts to avoid preemption between reading the 'ttbr0' * variable and the MSR. A context switch could trigger an ASID * roll-over and an update of 'ttbr0'. */ local_irq_save(flags); write_sysreg(current_thread_info()->ttbr0, ttbr0_el1); isb(); local_irq_restore(flags); } static inline bool uaccess_ttbr0_disable(void) { if (!system_uses_ttbr0_pan()) return false; __uaccess_ttbr0_disable(); return true; } static inline bool uaccess_ttbr0_enable(void) { if (!system_uses_ttbr0_pan()) return false; __uaccess_ttbr0_enable(); return true; } #else static inline bool uaccess_ttbr0_disable(void) { return false; } static inline bool uaccess_ttbr0_enable(void) { return false; } #endif #define __uaccess_disable(alt) \ do { \ if (!uaccess_ttbr0_disable()) \ asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), alt, \ CONFIG_ARM64_PAN)); \ } while (0) #define __uaccess_enable(alt) \ do { \ if (!uaccess_ttbr0_enable()) \ asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), alt, \ CONFIG_ARM64_PAN)); \ } while (0) static inline void uaccess_disable(void) { __uaccess_disable(ARM64_HAS_PAN); } static inline void uaccess_enable(void) { __uaccess_enable(ARM64_HAS_PAN); } /* * These functions are no-ops when UAO is present. */ static inline void uaccess_disable_not_uao(void) { __uaccess_disable(ARM64_ALT_PAN_NOT_UAO); } static inline void uaccess_enable_not_uao(void) { __uaccess_enable(ARM64_ALT_PAN_NOT_UAO); } /* * The "__xxx" versions of the user access functions do not verify the address * space - it must have been done previously with a separate "access_ok()" * call. * * The "__xxx_error" versions set the third argument to -EFAULT if an error * occurs, and leave it unchanged on success. */ #define __get_user_asm(instr, alt_instr, reg, x, addr, err, feature) \ asm volatile( \ "1:"ALTERNATIVE(instr " " reg "1, [%2]\n", \ alt_instr " " reg "1, [%2]\n", feature) \ "2:\n" \ " .section .fixup, \"ax\"\n" \ " .align 2\n" \ "3: mov %w0, %3\n" \ " mov %1, #0\n" \ " b 2b\n" \ " .previous\n" \ _ASM_EXTABLE(1b, 3b) \ : "+r" (err), "=&r" (x) \ : "r" (addr), "i" (-EFAULT)) #define __get_user_err(x, ptr, err) \ do { \ unsigned long __gu_val; \ __chk_user_ptr(ptr); \ uaccess_enable_not_uao(); \ switch (sizeof(*(ptr))) { \ case 1: \ __get_user_asm("ldrb", "ldtrb", "%w", __gu_val, (ptr), \ (err), ARM64_HAS_UAO); \ break; \ case 2: \ __get_user_asm("ldrh", "ldtrh", "%w", __gu_val, (ptr), \ (err), ARM64_HAS_UAO); \ break; \ case 4: \ __get_user_asm("ldr", "ldtr", "%w", __gu_val, (ptr), \ (err), ARM64_HAS_UAO); \ break; \ case 8: \ __get_user_asm("ldr", "ldtr", "%", __gu_val, (ptr), \ (err), ARM64_HAS_UAO); \ break; \ default: \ BUILD_BUG(); \ } \ uaccess_disable_not_uao(); \ (x) = (__force __typeof__(*(ptr)))__gu_val; \ } while (0) #define __get_user(x, ptr) \ ({ \ int __gu_err = 0; \ __get_user_err((x), (ptr), __gu_err); \ __gu_err; \ }) #define __get_user_error(x, ptr, err) \ ({ \ __get_user_err((x), (ptr), (err)); \ (void)0; \ }) #define __get_user_unaligned __get_user #define get_user(x, ptr) \ ({ \ __typeof__(*(ptr)) __user *__p = (ptr); \ might_fault(); \ access_ok(VERIFY_READ, __p, sizeof(*__p)) ? \ __get_user((x), __p) : \ ((x) = 0, -EFAULT); \ }) #define __put_user_asm(instr, alt_instr, reg, x, addr, err, feature) \ asm volatile( \ "1:"ALTERNATIVE(instr " " reg "1, [%2]\n", \ alt_instr " " reg "1, [%2]\n", feature) \ "2:\n" \ " .section .fixup,\"ax\"\n" \ " .align 2\n" \ "3: mov %w0, %3\n" \ " b 2b\n" \ " .previous\n" \ _ASM_EXTABLE(1b, 3b) \ : "+r" (err) \ : "r" (x), "r" (addr), "i" (-EFAULT)) #define __put_user_err(x, ptr, err) \ do { \ __typeof__(*(ptr)) __pu_val = (x); \ __chk_user_ptr(ptr); \ uaccess_enable_not_uao(); \ switch (sizeof(*(ptr))) { \ case 1: \ __put_user_asm("strb", "sttrb", "%w", __pu_val, (ptr), \ (err), ARM64_HAS_UAO); \ break; \ case 2: \ __put_user_asm("strh", "sttrh", "%w", __pu_val, (ptr), \ (err), ARM64_HAS_UAO); \ break; \ case 4: \ __put_user_asm("str", "sttr", "%w", __pu_val, (ptr), \ (err), ARM64_HAS_UAO); \ break; \ case 8: \ __put_user_asm("str", "sttr", "%", __pu_val, (ptr), \ (err), ARM64_HAS_UAO); \ break; \ default: \ BUILD_BUG(); \ } \ uaccess_disable_not_uao(); \ } while (0) #define __put_user(x, ptr) \ ({ \ int __pu_err = 0; \ __put_user_err((x), (ptr), __pu_err); \ __pu_err; \ }) #define __put_user_error(x, ptr, err) \ ({ \ __put_user_err((x), (ptr), (err)); \ (void)0; \ }) #define __put_user_unaligned __put_user #define put_user(x, ptr) \ ({ \ __typeof__(*(ptr)) __user *__p = (ptr); \ might_fault(); \ access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ? \ __put_user((x), __p) : \ -EFAULT; \ }) extern unsigned long __must_check __arch_copy_from_user(void *to, const void __user *from, unsigned long n); #define raw_copy_from_user __arch_copy_from_user extern unsigned long __must_check __arch_copy_to_user(void __user *to, const void *from, unsigned long n); #define raw_copy_to_user __arch_copy_to_user extern unsigned long __must_check raw_copy_in_user(void __user *to, const void __user *from, unsigned long n); extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n); #define INLINE_COPY_TO_USER #define INLINE_COPY_FROM_USER static inline unsigned long __must_check clear_user(void __user *to, unsigned long n) { if (access_ok(VERIFY_WRITE, to, n)) n = __clear_user(to, n); return n; } extern long strncpy_from_user(char *dest, const char __user *src, long count); extern __must_check long strlen_user(const char __user *str); extern __must_check long strnlen_user(const char __user *str, long n); #endif /* __ASM_UACCESS_H */