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/* SPDX-License-Identifier: GPL-2.0 / #ifndef _ASM_X86_UACCESS_H #define _ASM_X86_UACCESS_H / * User space memory access functions / #include <linux/compiler.h> #include <linux/kasan-checks.h> #include <linux/string.h> #include <asm/asm.h> #include <asm/page.h> #include <asm/smap.h> #include <asm/extable.h> / * The fs value determines whether argument validity checking should be * performed or not. If get_fs() == USER_DS, checking is performed, with * get_fs() == KERNEL_DS, checking is bypassed. * * For historical reasons, these macros are grossly misnamed. / #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) #define KERNEL_DS MAKE_MM_SEG(-1UL) #define USER_DS MAKE_MM_SEG(TASK_SIZE_MAX) #define get_fs() (current->thread.addr_limit) static inline void set_fs(mm_segment_t fs) { current->thread.addr_limit = fs; / On user-mode return, check fs is correct / set_thread_flag(TIF_FSCHECK); } #define segment_eq(a, b) ((a).seg == (b).seg) #define user_addr_max() (current->thread.addr_limit.seg) / * Test whether a block of memory is a valid user space address. * Returns 0 if the range is valid, nonzero otherwise. / static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, unsigned long limit) { / * If we have used "sizeof()" for the size, * we know it won't overflow the limit (but * it might overflow the 'addr', so it's * important to subtract the size from the * limit, not add it to the address). / if (__builtin_constant_p(size)) return unlikely(addr > limit - size); / Arbitrary sizes? Be careful about overflow / addr += size; if (unlikely(addr < size)) return true; return unlikely(addr > limit); } #define __range_not_ok(addr, size, limit) \ ({ \ __chk_user_ptr(addr); \ __chk_range_not_ok((unsigned long __force)(addr), size, limit); \ }) #ifdef CONFIG_DEBUG_ATOMIC_SLEEP static inline bool pagefault_disabled(void); # define WARN_ON_IN_IRQ() \ WARN_ON_ONCE(!in_task() && !pagefault_disabled()) #else # define WARN_ON_IN_IRQ() #endif /* * access_ok - Checks if a user space pointer is valid * @addr: User space pointer to start of block to check * @size: Size of block to check * * Context: User context only. This function may sleep if pagefaults are * enabled. * * Checks if a pointer to a block of memory in user space is valid. * * Note that, depending on architecture, this function probably just * checks that the pointer is in the user space range - after calling * this function, memory access functions may still return -EFAULT. * * Return: true (nonzero) if the memory block may be valid, false (zero) * if it is definitely invalid. / #define access_ok(addr, size) \ ({ \ WARN_ON_IN_IRQ(); \ likely(!__range_not_ok(addr, size, user_addr_max())); \ }) / * These are the main single-value transfer routines. They automatically * use the right size if we just have the right pointer type. * * This gets kind of ugly. We want to return _two_ values in "get_user()" * and yet we don't want to do any pointers, because that is too much * of a performance impact. Thus we have a few rather ugly macros here, * and hide all the ugliness from the user. * * The "__xxx" versions of the user access functions are versions that * do not verify the address space, that must have been done previously * with a separate "access_ok()" call (this is used when we do multiple * accesses to the same area of user memory). / extern int __get_user_1(void); extern int __get_user_2(void); extern int __get_user_4(void); extern int __get_user_8(void); extern int __get_user_bad(void); #define __uaccess_begin() stac() #define __uaccess_end() clac() #define __uaccess_begin_nospec() \ ({ \ stac(); \ barrier_nospec(); \ }) / * This is a type: either unsigned long, if the argument fits into * that type, or otherwise unsigned long long. / #define __inttype(x) \ __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) /* * get_user - Get a simple variable from user space. * @x: Variable to store result. * @ptr: Source address, in user space. * * Context: User context only. This function may sleep if pagefaults are * enabled. * * This macro copies a single simple variable from user space to kernel * space. It supports simple types like char and int, but not larger * data types like structures or arrays. * * @ptr must have pointer-to-simple-variable type, and the result of * dereferencing @ptr must be assignable to @x without a cast. * * Return: zero on success, or -EFAULT on error. * On error, the variable @x is set to zero. / / * Careful: we have to cast the result to the type of the pointer * for sign reasons. * * The use of _ASM_DX as the register specifier is a bit of a * simplification, as gcc only cares about it as the starting point * and not size: for a 64-bit value it will use %ecx:%edx on 32 bits * (%ecx being the next register in gcc's x86 register sequence), and * %rdx on 64 bits. * * Clang/LLVM cares about the size of the register, but still wants * the base register for something that ends up being a pair. / #define get_user(x, ptr) \ ({ \ int __ret_gu; \ register __inttype((ptr)) __val_gu asm("%"_ASM_DX); \ __chk_user_ptr(ptr); \ might_fault(); \ asm volatile("call __get_user_%P4" \ : "=a" (__ret_gu), "=r" (__val_gu), \ ASM_CALL_CONSTRAINT \ : "0" (ptr), "i" (sizeof((ptr)))); \ (x) = (__force __typeof__((ptr))) __val_gu; \ __builtin_expect(__ret_gu, 0); \ }) #define __put_user_x(size, x, ptr, __ret_pu) \ asm volatile("call __put_user_" #size : "=a" (__ret_pu) \ : "0" ((typeof((ptr)))(x)), "c" (ptr) : "ebx") #ifdef CONFIG_X86_32 #define __put_user_goto_u64(x, addr, label) \ asm_volatile_goto("\n" \ "1: movl %%eax,0(%1)\n" \ "2: movl %%edx,4(%1)\n" \ _ASM_EXTABLE_UA(1b, %l2) \ _ASM_EXTABLE_UA(2b, %l2) \ : : "A" (x), "r" (addr) \ : : label) #define __put_user_asm_ex_u64(x, addr) \ asm volatile("\n" \ "1: movl %%eax,0(%1)\n" \ "2: movl %%edx,4(%1)\n" \ "3:" \ _ASM_EXTABLE_EX(1b, 2b) \ _ASM_EXTABLE_EX(2b, 3b) \ : : "A" (x), "r" (addr)) #define __put_user_x8(x, ptr, __ret_pu) \ asm volatile("call __put_user_8" : "=a" (__ret_pu) \ : "A" ((typeof((ptr)))(x)), "c" (ptr) : "ebx") #else #define __put_user_goto_u64(x, ptr, label) \ __put_user_goto(x, ptr, "q", "", "er", label) #define __put_user_asm_ex_u64(x, addr) \ __put_user_asm_ex(x, addr, "q", "", "er") #define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu) #endif extern void __put_user_bad(void); /* * Strange magic calling convention: pointer in %ecx, * value in %eax(:%edx), return value in %eax. clobbers %rbx / extern void __put_user_1(void); extern void __put_user_2(void); extern void __put_user_4(void); extern void __put_user_8(void); /* * put_user - Write a simple value into user space. * @x: Value to copy to user space. * @ptr: Destination address, in user space. * * Context: User context only. This function may sleep if pagefaults are * enabled. * * This macro copies a single simple value from kernel space to user * space. It supports simple types like char and int, but not larger * data types like structures or arrays. * * @ptr must have pointer-to-simple-variable type, and @x must be assignable * to the result of dereferencing @ptr. * * Return: zero on success, or -EFAULT on error. / #define put_user(x, ptr) \ ({ \ int __ret_pu; \ __typeof__((ptr)) __pu_val; \ __chk_user_ptr(ptr); \ might_fault(); \ __pu_val = x; \ switch (sizeof((ptr))) { \ case 1: \ __put_user_x(1, __pu_val, ptr, __ret_pu); \ break; \ case 2: \ __put_user_x(2, __pu_val, ptr, __ret_pu); \ break; \ case 4: \ __put_user_x(4, __pu_val, ptr, __ret_pu); \ break; \ case 8: \ __put_user_x8(__pu_val, ptr, __ret_pu); \ break; \ default: \ __put_user_x(X, __pu_val, ptr, __ret_pu); \ break; \ } \ __builtin_expect(__ret_pu, 0); \ }) #define __put_user_size(x, ptr, size, label) \ do { \ __chk_user_ptr(ptr); \ switch (size) { \ case 1: \ __put_user_goto(x, ptr, "b", "b", "iq", label); \ break; \ case 2: \ __put_user_goto(x, ptr, "w", "w", "ir", label); \ break; \ case 4: \ __put_user_goto(x, ptr, "l", "k", "ir", label); \ break; \ case 8: \ __put_user_goto_u64(x, ptr, label); \ break; \ default: \ __put_user_bad(); \ } \ } while (0) / * This doesn't do __uaccess_begin/end - the exception handling * around it must do that. / #define __put_user_size_ex(x, ptr, size) \ do { \ __chk_user_ptr(ptr); \ switch (size) { \ case 1: \ __put_user_asm_ex(x, ptr, "b", "b", "iq"); \ break; \ case 2: \ __put_user_asm_ex(x, ptr, "w", "w", "ir"); \ break; \ case 4: \ __put_user_asm_ex(x, ptr, "l", "k", "ir"); \ break; \ case 8: \ __put_user_asm_ex_u64((__typeof__(ptr))(x), ptr); \ break; \ default: \ __put_user_bad(); \ } \ } while (0) #ifdef CONFIG_X86_32 #define __get_user_asm_u64(x, ptr, retval, errret) \ ({ \ __typeof__(ptr) __ptr = (ptr); \ asm volatile("\n" \ "1: movl %2,%%eax\n" \ "2: movl %3,%%edx\n" \ "3:\n" \ ".section .fixup,\"ax\"\n" \ "4: mov %4,%0\n" \ " xorl %%eax,%%eax\n" \ " xorl %%edx,%%edx\n" \ " jmp 3b\n" \ ".previous\n" \ _ASM_EXTABLE_UA(1b, 4b) \ _ASM_EXTABLE_UA(2b, 4b) \ : "=r" (retval), "=&A"(x) \ : "m" (__m(__ptr)), "m" __m(((u32 __user )(__ptr)) + 1), \ "i" (errret), "0" (retval)); \ }) #define __get_user_asm_ex_u64(x, ptr) (x) = __get_user_bad() #else #define __get_user_asm_u64(x, ptr, retval, errret) \ __get_user_asm(x, ptr, retval, "q", "", "=r", errret) #define __get_user_asm_ex_u64(x, ptr) \ __get_user_asm_ex(x, ptr, "q", "", "=r") #endif #define __get_user_size(x, ptr, size, retval, errret) \ do { \ retval = 0; \ __chk_user_ptr(ptr); \ switch (size) { \ case 1: \ __get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \ break; \ case 2: \ __get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \ break; \ case 4: \ __get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \ break; \ case 8: \ __get_user_asm_u64(x, ptr, retval, errret); \ break; \ default: \ (x) = __get_user_bad(); \ } \ } while (0) #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \ asm volatile("\n" \ "1: mov"itype" %2,%"rtype"1\n" \ "2:\n" \ ".section .fixup,\"ax\"\n" \ "3: mov %3,%0\n" \ " xor"itype" %"rtype"1,%"rtype"1\n" \ " jmp 2b\n" \ ".previous\n" \ _ASM_EXTABLE_UA(1b, 3b) \ : "=r" (err), ltype(x) \ : "m" (__m(addr)), "i" (errret), "0" (err)) / * This doesn't do __uaccess_begin/end - the exception handling * around it must do that. / #define __get_user_size_ex(x, ptr, size) \ do { \ __chk_user_ptr(ptr); \ switch (size) { \ case 1: \ __get_user_asm_ex(x, ptr, "b", "b", "=q"); \ break; \ case 2: \ __get_user_asm_ex(x, ptr, "w", "w", "=r"); \ break; \ case 4: \ __get_user_asm_ex(x, ptr, "l", "k", "=r"); \ break; \ case 8: \ __get_user_asm_ex_u64(x, ptr); \ break; \ default: \ (x) = __get_user_bad(); \ } \ } while (0) #define __get_user_asm_ex(x, addr, itype, rtype, ltype) \ asm volatile("1: mov"itype" %1,%"rtype"0\n" \ "2:\n" \ ".section .fixup,\"ax\"\n" \ "3:xor"itype" %"rtype"0,%"rtype"0\n" \ " jmp 2b\n" \ ".previous\n" \ _ASM_EXTABLE_EX(1b, 3b) \ : ltype(x) : "m" (__m(addr))) #define __put_user_nocheck(x, ptr, size) \ ({ \ __label__ __pu_label; \ int __pu_err = -EFAULT; \ __typeof__((ptr)) __pu_val = (x); \ __typeof__(ptr) __pu_ptr = (ptr); \ __typeof__(size) __pu_size = (size); \ __uaccess_begin(); \ __put_user_size(__pu_val, __pu_ptr, __pu_size, __pu_label); \ __pu_err = 0; \ __pu_label: \ __uaccess_end(); \ __builtin_expect(__pu_err, 0); \ }) #define __get_user_nocheck(x, ptr, size) \ ({ \ int __gu_err; \ __inttype((ptr)) __gu_val; \ __typeof__(ptr) __gu_ptr = (ptr); \ __typeof__(size) __gu_size = (size); \ __uaccess_begin_nospec(); \ __get_user_size(__gu_val, __gu_ptr, __gu_size, __gu_err, -EFAULT); \ __uaccess_end(); \ (x) = (__force __typeof__((ptr)))__gu_val; \ __builtin_expect(__gu_err, 0); \ }) #ifdef CONFIG_CC_HAS_ASM_GOTO_TIED_OUTPUT #define __try_cmpxchg_user_asm(itype, ltype, _ptr, _pold, _new, label) ({ \ bool success; \ __typeof__(_ptr) _old = (__typeof__(_ptr))(_pold); \ __typeof__((_ptr)) __old = _old; \ __typeof__((_ptr)) __new = (_new); \ asm_volatile_goto("\n" \ "1: " LOCK_PREFIX "cmpxchg"itype" %[new], %[ptr]\n"\ _ASM_EXTABLE_UA(1b, %l[label]) \ : CC_OUT(z) (success), \ [ptr] "+m" (_ptr), \ [old] "+a" (__old) \ : [new] ltype (__new) \ : "memory" \ : label); \ if (unlikely(!success)) \ _old = __old; \ likely(success); }) #ifdef CONFIG_X86_32 #define __try_cmpxchg64_user_asm(_ptr, _pold, _new, label) ({ \ bool success; \ __typeof__(_ptr) _old = (__typeof__(_ptr))(_pold); \ __typeof__((_ptr)) __old = _old; \ __typeof__((_ptr)) __new = (_new); \ asm_volatile_goto("\n" \ "1: " LOCK_PREFIX "cmpxchg8b %[ptr]\n" \ _ASM_EXTABLE_UA(1b, %l[label]) \ : CC_OUT(z) (success), \ "+A" (__old), \ [ptr] "+m" (_ptr) \ : "b" ((u32)__new), \ "c" ((u32)((u64)__new >> 32)) \ : "memory" \ : label); \ if (unlikely(!success)) \ _old = __old; \ likely(success); }) #endif // CONFIG_X86_32 #else // !CONFIG_CC_HAS_ASM_GOTO_TIED_OUTPUT #define __try_cmpxchg_user_asm(itype, ltype, _ptr, _pold, _new, label) ({ \ int __err = 0; \ bool success; \ __typeof__(_ptr) _old = (__typeof__(_ptr))(_pold); \ __typeof__((_ptr)) __old = _old; \ __typeof__((_ptr)) __new = (_new); \ asm volatile("\n" \ "1: " LOCK_PREFIX "cmpxchg"itype" %[new], %[ptr]\n"\ CC_SET(z) \ "2:\n" \ _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, \ %[errout]) \ : CC_OUT(z) (success), \ [errout] "+r" (__err), \ [ptr] "+m" (_ptr), \ [old] "+a" (__old) \ : [new] ltype (__new) \ : "memory"); \ if (unlikely(__err)) \ goto label; \ if (unlikely(!success)) \ _old = __old; \ likely(success); }) #ifdef CONFIG_X86_32 / * Unlike the normal CMPXCHG, hardcode ECX for both success/fail and error. * There are only six GPRs available and four (EAX, EBX, ECX, and EDX) are * hardcoded by CMPXCHG8B, leaving only ESI and EDI. If the compiler uses * both ESI and EDI for the memory operand, compilation will fail if the error * is an input+output as there will be no register available for input. / #define __try_cmpxchg64_user_asm(_ptr, _pold, _new, label) ({ \ int __result; \ __typeof__(_ptr) _old = (__typeof__(_ptr))(_pold); \ __typeof__((_ptr)) __old = _old; \ __typeof__((_ptr)) __new = (_new); \ asm volatile("\n" \ "1: " LOCK_PREFIX "cmpxchg8b %[ptr]\n" \ "mov $0, %%ecx\n\t" \ "setz %%cl\n" \ "2:\n" \ _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %%ecx) \ : [result]"=c" (__result), \ "+A" (__old), \ [ptr] "+m" (_ptr) \ : "b" ((u32)__new), \ "c" ((u32)((u64)__new >> 32)) \ : "memory", "cc"); \ if (unlikely(__result < 0)) \ goto label; \ if (unlikely(!__result)) \ _old = __old; \ likely(__result); }) #endif // CONFIG_X86_32 #endif // CONFIG_CC_HAS_ASM_GOTO_TIED_OUTPUT /* FIXME: this hack is definitely wrong -AK / struct __large_struct { unsigned long buf[100]; }; #define __m(x) ((struct __large_struct __user )(x)) / * Tell gcc we read from memory instead of writing: this is because * we do not write to any memory gcc knows about, so there are no * aliasing issues. / #define __put_user_goto(x, addr, itype, rtype, ltype, label) \ asm_volatile_goto("\n" \ "1: mov"itype" %"rtype"0,%1\n" \ _ASM_EXTABLE_UA(1b, %l2) \ : : ltype(x), "m" (__m(addr)) \ : : label) #define __put_user_failed(x, addr, itype, rtype, ltype, errret) \ ({ __label__ __puflab; \ int __pufret = errret; \ __put_user_goto(x,addr,itype,rtype,ltype,__puflab); \ __pufret = 0; \ __puflab: __pufret; }) #define __put_user_asm(x, addr, retval, itype, rtype, ltype, errret) do { \ retval = __put_user_failed(x, addr, itype, rtype, ltype, errret); \ } while (0) #define __put_user_asm_ex(x, addr, itype, rtype, ltype) \ asm volatile("1: mov"itype" %"rtype"0,%1\n" \ "2:\n" \ _ASM_EXTABLE_EX(1b, 2b) \ : : ltype(x), "m" (__m(addr))) / * uaccess_try and catch / #define uaccess_try do { \ current->thread.uaccess_err = 0; \ __uaccess_begin(); \ barrier(); #define uaccess_try_nospec do { \ current->thread.uaccess_err = 0; \ __uaccess_begin_nospec(); \ #define uaccess_catch(err) \ __uaccess_end(); \ (err) \|= (current->thread.uaccess_err ? -EFAULT : 0); \ } while (0) /* * __get_user - Get a simple variable from user space, with less checking. * @x: Variable to store result. * @ptr: Source address, in user space. * * Context: User context only. This function may sleep if pagefaults are * enabled. * * This macro copies a single simple variable from user space to kernel * space. It supports simple types like char and int, but not larger * data types like structures or arrays. * * @ptr must have pointer-to-simple-variable type, and the result of * dereferencing @ptr must be assignable to @x without a cast. * * Caller must check the pointer with access_ok() before calling this * function. * * Return: zero on success, or -EFAULT on error. * On error, the variable @x is set to zero. / #define __get_user(x, ptr) \ __get_user_nocheck((x), (ptr), sizeof((ptr))) /** * __put_user - Write a simple value into user space, with less checking. * @x: Value to copy to user space. * @ptr: Destination address, in user space. * * Context: User context only. This function may sleep if pagefaults are * enabled. * * This macro copies a single simple value from kernel space to user * space. It supports simple types like char and int, but not larger * data types like structures or arrays. * * @ptr must have pointer-to-simple-variable type, and @x must be assignable * to the result of dereferencing @ptr. * * Caller must check the pointer with access_ok() before calling this * function. * * Return: zero on success, or -EFAULT on error. / #define __put_user(x, ptr) \ __put_user_nocheck((__typeof__((ptr)))(x), (ptr), sizeof((ptr))) / * {get\|put}_user_try and catch * * get_user_try { * get_user_ex(...); * } get_user_catch(err) / #define get_user_try uaccess_try_nospec #define get_user_catch(err) uaccess_catch(err) #define get_user_ex(x, ptr) do { \ unsigned long __gue_val; \ __get_user_size_ex((__gue_val), (ptr), (sizeof((ptr)))); \ (x) = (__force __typeof__((ptr)))__gue_val; \ } while (0) #define put_user_try uaccess_try #define put_user_catch(err) uaccess_catch(err) #define put_user_ex(x, ptr) \ __put_user_size_ex((__typeof__((ptr)))(x), (ptr), sizeof((ptr))) extern unsigned long copy_from_user_nmi(void to, const void __user from, unsigned long n); extern __must_check long strncpy_from_user(char dst, const char __user src, long count); extern __must_check long strnlen_user(const char __user str, long n); unsigned long __must_check clear_user(void __user mem, unsigned long len); unsigned long __must_check __clear_user(void __user mem, unsigned long len); extern void __cmpxchg_wrong_size(void) __compiletime_error("Bad argument size for cmpxchg"); #define __user_atomic_cmpxchg_inatomic(uval, ptr, old, new, size) \ ({ \ int __ret = 0; \ __typeof__((ptr)) __old = (old); \ __typeof__((ptr)) __new = (new); \ __uaccess_begin_nospec(); \ switch (size) { \ case 1: \ { \ asm volatile("\n" \ "1:\t" LOCK_PREFIX "cmpxchgb %4, %2\n" \ "2:\n" \ "\t.section .fixup, \"ax\"\n" \ "3:\tmov %3, %0\n" \ "\tjmp 2b\n" \ "\t.previous\n" \ _ASM_EXTABLE_UA(1b, 3b) \ : "+r" (__ret), "=a" (__old), "+m" ((ptr)) \ : "i" (-EFAULT), "q" (__new), "1" (__old) \ : "memory" \ ); \ break; \ } \ case 2: \ { \ asm volatile("\n" \ "1:\t" LOCK_PREFIX "cmpxchgw %4, %2\n" \ "2:\n" \ "\t.section .fixup, \"ax\"\n" \ "3:\tmov %3, %0\n" \ "\tjmp 2b\n" \ "\t.previous\n" \ _ASM_EXTABLE_UA(1b, 3b) \ : "+r" (__ret), "=a" (__old), "+m" ((ptr)) \ : "i" (-EFAULT), "r" (__new), "1" (__old) \ : "memory" \ ); \ break; \ } \ case 4: \ { \ asm volatile("\n" \ "1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n" \ "2:\n" \ "\t.section .fixup, \"ax\"\n" \ "3:\tmov %3, %0\n" \ "\tjmp 2b\n" \ "\t.previous\n" \ _ASM_EXTABLE_UA(1b, 3b) \ : "+r" (__ret), "=a" (__old), "+m" ((ptr)) \ : "i" (-EFAULT), "r" (__new), "1" (__old) \ : "memory" \ ); \ break; \ } \ case 8: \ { \ if (!IS_ENABLED(CONFIG_X86_64)) \ __cmpxchg_wrong_size(); \ \ asm volatile("\n" \ "1:\t" LOCK_PREFIX "cmpxchgq %4, %2\n" \ "2:\n" \ "\t.section .fixup, \"ax\"\n" \ "3:\tmov %3, %0\n" \ "\tjmp 2b\n" \ "\t.previous\n" \ _ASM_EXTABLE_UA(1b, 3b) \ : "+r" (__ret), "=a" (__old), "+m" ((ptr)) \ : "i" (-EFAULT), "r" (__new), "1" (__old) \ : "memory" \ ); \ break; \ } \ default: \ __cmpxchg_wrong_size(); \ } \ __uaccess_end(); \ (uval) = __old; \ __ret; \ }) #define user_atomic_cmpxchg_inatomic(uval, ptr, old, new) \ ({ \ access_ok((ptr), sizeof((ptr))) ? \ __user_atomic_cmpxchg_inatomic((uval), (ptr), \ (old), (new), sizeof((ptr))) : \ -EFAULT; \ }) / * movsl can be slow when source and dest are not both 8-byte aligned / #ifdef CONFIG_X86_INTEL_USERCOPY extern struct movsl_mask { int mask; } ____cacheline_aligned_in_smp movsl_mask; #endif #define ARCH_HAS_NOCACHE_UACCESS 1 #ifdef CONFIG_X86_32 # include <asm/uaccess_32.h> #else # include <asm/uaccess_64.h> #endif / * We rely on the nested NMI work to allow atomic faults from the NMI path; the * nested NMI paths are careful to preserve CR2. * * Caller must use pagefault_enable/disable, or run in interrupt context, * and also do a uaccess_ok() check / #define __copy_from_user_nmi __copy_from_user_inatomic / * The "unsafe" user accesses aren't really "unsafe", but the naming * is a big fat warning: you have to not only do the access_ok() * checking before using them, but you have to surround them with the * user_access_begin/end() pair. / static __must_check __always_inline bool user_access_begin(const void __user ptr, size_t len) { if (unlikely(!access_ok(ptr,len))) return 0; __uaccess_begin_nospec(); return 1; } #define user_access_begin(a,b) user_access_begin(a,b) #define user_access_end() __uaccess_end() #define user_access_save() smap_save() #define user_access_restore(x) smap_restore(x) #define unsafe_put_user(x, ptr, label) \ __put_user_size((__typeof__((ptr)))(x), (ptr), sizeof((ptr)), label) #define unsafe_get_user(x, ptr, err_label) \ do { \ int __gu_err; \ __inttype((ptr)) __gu_val; \ __get_user_size(__gu_val, (ptr), sizeof((ptr)), __gu_err, -EFAULT); \ (x) = (__force __typeof__((ptr)))__gu_val; \ if (unlikely(__gu_err)) goto err_label; \ } while (0) extern void __try_cmpxchg_user_wrong_size(void); #ifndef CONFIG_X86_32 #define __try_cmpxchg64_user_asm(_ptr, _oldp, _nval, _label) \ __try_cmpxchg_user_asm("q", "r", (_ptr), (_oldp), (_nval), _label) #endif / * Force the pointer to u<size> to match the size expected by the asm helper. * clang/LLVM compiles all cases and only discards the unused paths after * processing errors, which breaks i386 if the pointer is an 8-byte value. / #define unsafe_try_cmpxchg_user(_ptr, _oldp, _nval, _label) ({ \ bool __ret; \ __chk_user_ptr(_ptr); \ switch (sizeof((_ptr))) { \ case 1: __ret = __try_cmpxchg_user_asm("b", "q", \ (__force u8 )(_ptr), (_oldp), \ (_nval), _label); \ break; \ case 2: __ret = __try_cmpxchg_user_asm("w", "r", \ (__force u16 )(_ptr), (_oldp), \ (_nval), _label); \ break; \ case 4: __ret = __try_cmpxchg_user_asm("l", "r", \ (__force u32 )(_ptr), (_oldp), \ (_nval), _label); \ break; \ case 8: __ret = __try_cmpxchg64_user_asm((__force u64 )(_ptr), (_oldp),\ (_nval), _label); \ break; \ default: __try_cmpxchg_user_wrong_size(); \ } \ __ret; }) /* "Returns" 0 on success, 1 on failure, -EFAULT if the access faults. / #define __try_cmpxchg_user(_ptr, _oldp, _nval, _label) ({ \ int __ret = -EFAULT; \ __uaccess_begin_nospec(); \ __ret = !unsafe_try_cmpxchg_user(_ptr, _oldp, _nval, _label); \ _label: \ __uaccess_end(); \ __ret; \ }) / * We want the unsafe accessors to always be inlined and use * the error labels - thus the macro games. / #define unsafe_copy_loop(dst, src, len, type, label) \ while (len >= sizeof(type)) { \ unsafe_put_user((type )src,(type __user )dst,label); \ dst += sizeof(type); \ src += sizeof(type); \ len -= sizeof(type); \ } #define unsafe_copy_to_user(_dst,_src,_len,label) \ do { \ char __user __ucu_dst = (_dst); \ const char __ucu_src = (_src); \ size_t __ucu_len = (_len); \ unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u64, label); \ unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u32, label); \ unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u16, label); \ unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u8, label); \ } while (0) #endif /* _ASM_X86_UACCESS_H */

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