diff options
Diffstat (limited to 'arch/x86/include/asm/uaccess.h')
| -rw-r--r-- | arch/x86/include/asm/uaccess.h | 860 |
1 files changed, 479 insertions, 381 deletions
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 5ee26875baea..367297b188c3 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -1,143 +1,119 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_X86_UACCESS_H #define _ASM_X86_UACCESS_H /* * User space memory access functions */ -#include <linux/errno.h> #include <linux/compiler.h> -#include <linux/thread_info.h> +#include <linux/instrumented.h> +#include <linux/kasan-checks.h> +#include <linux/mm_types.h> #include <linux/string.h> +#include <linux/mmap_lock.h> #include <asm/asm.h> #include <asm/page.h> #include <asm/smap.h> +#include <asm/extable.h> +#include <asm/tlbflush.h> -#define VERIFY_READ 0 -#define VERIFY_WRITE 1 - -/* - * 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. - */ +#ifdef CONFIG_X86_32 +# include <asm/uaccess_32.h> +#else +# include <asm/uaccess_64.h> +#endif -#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) +#include <asm-generic/access_ok.h> -#define KERNEL_DS MAKE_MM_SEG(-1UL) -#define USER_DS MAKE_MM_SEG(TASK_SIZE_MAX) +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_nocheck_1(void); +extern int __get_user_nocheck_2(void); +extern int __get_user_nocheck_4(void); +extern int __get_user_nocheck_8(void); +extern int __get_user_bad(void); -#define get_ds() (KERNEL_DS) -#define get_fs() (current_thread_info()->addr_limit) -#define set_fs(x) (current_thread_info()->addr_limit = (x)) +#define __uaccess_begin() stac() +#define __uaccess_end() clac() +#define __uaccess_begin_nospec() \ +({ \ + stac(); \ + barrier_nospec(); \ +}) -#define segment_eq(a, b) ((a).seg == (b).seg) +/* + * This is the smallest unsigned integer type that can fit a value + * (up to 'long long') + */ +#define __inttype(x) __typeof__( \ + __typefits(x,char, \ + __typefits(x,short, \ + __typefits(x,int, \ + __typefits(x,long,0ULL))))) -#define user_addr_max() (current_thread_info()->addr_limit.seg) -#define __addr_ok(addr) \ - ((unsigned long __force)(addr) < user_addr_max()) +#define __typefits(x,type,not) \ + __builtin_choose_expr(sizeof(x)<=sizeof(type),(unsigned type)0,not) /* - * Test whether a block of memory is a valid user space address. - * Returns 0 if the range is valid, nonzero otherwise. + * This is used for both get_user() and __get_user() to expand to + * the proper special function call that has odd calling conventions + * due to returning both a value and an error, and that depends on + * the size of the pointer passed in. * - * This is equivalent to the following test: - * (u33)addr + (u33)size > (u33)current->addr_limit.seg (u65 for x86_64) + * Careful: we have to cast the result to the type of the pointer + * for sign reasons. * - * This needs 33-bit (65-bit for x86_64) arithmetic. We have a carry... + * 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 __range_not_ok(addr, size, limit) \ +#define do_get_user_call(fn,x,ptr) \ ({ \ - unsigned long flag, roksum; \ - __chk_user_ptr(addr); \ - asm("add %3,%1 ; sbb %0,%0 ; cmp %1,%4 ; sbb $0,%0" \ - : "=&r" (flag), "=r" (roksum) \ - : "1" (addr), "g" ((long)(size)), \ - "rm" (limit)); \ - flag; \ + int __ret_gu; \ + register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX); \ + __chk_user_ptr(ptr); \ + asm volatile("call __" #fn "_%c[size]" \ + : "=a" (__ret_gu), "=r" (__val_gu), \ + ASM_CALL_CONSTRAINT \ + : "0" (ptr), [size] "i" (sizeof(*(ptr)))); \ + instrument_get_user(__val_gu); \ + (x) = (__force __typeof__(*(ptr))) __val_gu; \ + __builtin_expect(__ret_gu, 0); \ }) /** - * access_ok: - Checks if a user space pointer is valid - * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that - * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe - * to write to a block, it is always safe to read from it. - * @addr: User space pointer to start of block to check - * @size: Size of block to check - * - * Context: User context only. This function may sleep. - * - * Checks if a pointer to a block of memory in user space is valid. - * - * Returns true (nonzero) if the memory block may be valid, false (zero) - * if it is definitely invalid. + * get_user - Get a simple variable from user space. + * @x: Variable to store result. + * @ptr: Source address, in user space. * - * 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. - */ -#define access_ok(type, addr, size) \ - (likely(__range_not_ok(addr, size, user_addr_max()) == 0)) - -/* - * The exception table consists of pairs of addresses relative to the - * exception table enty itself: the first is the address of an - * instruction that is allowed to fault, and the second is the address - * at which the program should continue. No registers are modified, - * so it is entirely up to the continuation code to figure out what to - * do. + * Context: User context only. This function may sleep if pagefaults are + * enabled. * - * All the routines below use bits of fixup code that are out of line - * with the main instruction path. This means when everything is well, - * we don't even have to jump over them. Further, they do not intrude - * on our cache or tlb entries. - */ - -struct exception_table_entry { - int insn, fixup; -}; -/* This is not the generic standard exception_table_entry format */ -#define ARCH_HAS_SORT_EXTABLE -#define ARCH_HAS_SEARCH_EXTABLE - -extern int fixup_exception(struct pt_regs *regs); -extern int early_fixup_exception(unsigned long *ip); - -/* - * These are the main single-value transfer routines. They automatically - * use the right size if we just have the right pointer type. + * 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. * - * 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. + * @ptr must have pointer-to-simple-variable type, and the result of + * dereferencing @ptr must be assignable to @x without a cast. * - * 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); - -/* - * This is a type: either unsigned long, if the argument fits into - * that type, or otherwise unsigned long long. + * Return: zero on success, or -EFAULT on error. + * On error, the variable @x is set to zero. */ -#define __inttype(x) \ -__typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) +#define get_user(x,ptr) ({ might_fault(); do_get_user_call(get_user,x,ptr); }) /** - * get_user: - Get a simple variable from user space. + * __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. + * 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 @@ -146,90 +122,79 @@ __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) * @ptr must have pointer-to-simple-variable type, and the result of * dereferencing @ptr must be assignable to @x without a cast. * - * Returns 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. + * Caller must check the pointer with access_ok() before calling this + * function. * - * The use of %edx 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. + * Return: zero on success, or -EFAULT on error. + * On error, the variable @x is set to zero. */ -#define get_user(x, ptr) \ -({ \ - int __ret_gu; \ - register __inttype(*(ptr)) __val_gu asm("%edx"); \ - __chk_user_ptr(ptr); \ - might_fault(); \ - asm volatile("call __get_user_%P3" \ - : "=a" (__ret_gu), "=r" (__val_gu) \ - : "0" (ptr), "i" (sizeof(*(ptr)))); \ - (x) = (__typeof__(*(ptr))) __val_gu; \ - __ret_gu; \ -}) - -#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") - +#define __get_user(x,ptr) do_get_user_call(get_user_nocheck,x,ptr) #ifdef CONFIG_X86_32 -#define __put_user_asm_u64(x, addr, err, errret) \ - asm volatile(ASM_STAC "\n" \ - "1: movl %%eax,0(%2)\n" \ - "2: movl %%edx,4(%2)\n" \ - "3: " ASM_CLAC "\n" \ - ".section .fixup,\"ax\"\n" \ - "4: movl %3,%0\n" \ - " jmp 3b\n" \ - ".previous\n" \ - _ASM_EXTABLE(1b, 4b) \ - _ASM_EXTABLE(2b, 4b) \ - : "=r" (err) \ - : "A" (x), "r" (addr), "i" (errret), "0" (err)) - -#define __put_user_asm_ex_u64(x, addr) \ - asm volatile(ASM_STAC "\n" \ - "1: movl %%eax,0(%1)\n" \ - "2: movl %%edx,4(%1)\n" \ - "3: " ASM_CLAC "\n" \ - _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") +#define __put_user_goto_u64(x, addr, label) \ + asm 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) + #else -#define __put_user_asm_u64(x, ptr, retval, errret) \ - __put_user_asm(x, ptr, retval, "q", "", "er", errret) -#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) +#define __put_user_goto_u64(x, ptr, label) \ + __put_user_goto(x, ptr, "q", "er", label) #endif extern void __put_user_bad(void); /* * Strange magic calling convention: pointer in %ecx, - * value in %eax(:%edx), return value in %eax. clobbers %rbx + * value in %eax(:%edx), return value in %ecx. 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); +extern void __put_user_nocheck_1(void); +extern void __put_user_nocheck_2(void); +extern void __put_user_nocheck_4(void); +extern void __put_user_nocheck_8(void); + +/* + * ptr must be evaluated and assigned to the temporary __ptr_pu before + * the assignment of x to __val_pu, to avoid any function calls + * involved in the ptr expression (possibly implicitly generated due + * to KASAN) from clobbering %ax. + */ +#define do_put_user_call(fn,x,ptr) \ +({ \ + int __ret_pu; \ + void __user *__ptr_pu; \ + register __typeof__(*(ptr)) __val_pu asm("%"_ASM_AX); \ + __typeof__(*(ptr)) __x = (x); /* eval x once */ \ + __typeof__(ptr) __ptr = (ptr); /* eval ptr once */ \ + __chk_user_ptr(__ptr); \ + __ptr_pu = __ptr; \ + __val_pu = __x; \ + asm volatile("call __" #fn "_%c[size]" \ + : "=c" (__ret_pu), \ + ASM_CALL_CONSTRAINT \ + : "0" (__ptr_pu), \ + "r" (__val_pu), \ + [size] "i" (sizeof(*(ptr))) \ + :"ebx"); \ + instrument_put_user(__x, __ptr, sizeof(*(ptr))); \ + __builtin_expect(__ret_pu, 0); \ +}) /** - * put_user: - Write a simple value into user space. + * 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. + * 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 @@ -238,166 +203,268 @@ extern void __put_user_8(void); * @ptr must have pointer-to-simple-variable type, and @x must be assignable * to the result of dereferencing @ptr. * - * Returns zero on success, or -EFAULT on error. + * 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; \ - } \ - __ret_pu; \ -}) +#define put_user(x, ptr) ({ might_fault(); do_put_user_call(put_user,x,ptr); }) -#define __put_user_size(x, ptr, size, retval, errret) \ -do { \ - retval = 0; \ - __chk_user_ptr(ptr); \ - switch (size) { \ - case 1: \ - __put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \ - break; \ - case 2: \ - __put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \ - break; \ - case 4: \ - __put_user_asm(x, ptr, retval, "l", "k", "ir", errret); \ - break; \ - case 8: \ - __put_user_asm_u64((__typeof__(*ptr))(x), ptr, retval, \ - errret); \ - break; \ - default: \ - __put_user_bad(); \ - } \ -} while (0) +/** + * __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) do_put_user_call(put_user_nocheck,x,ptr) -#define __put_user_size_ex(x, ptr, size) \ +#define __put_user_size(x, ptr, size, label) \ do { \ - __chk_user_ptr(ptr); \ + __typeof__(*(ptr)) __x = (x); /* eval x once */ \ + __typeof__(ptr) __ptr = (ptr); /* eval ptr once */ \ + __chk_user_ptr(__ptr); \ switch (size) { \ case 1: \ - __put_user_asm_ex(x, ptr, "b", "b", "iq"); \ + __put_user_goto(__x, __ptr, "b", "iq", label); \ break; \ case 2: \ - __put_user_asm_ex(x, ptr, "w", "w", "ir"); \ + __put_user_goto(__x, __ptr, "w", "ir", label); \ break; \ case 4: \ - __put_user_asm_ex(x, ptr, "l", "k", "ir"); \ + __put_user_goto(__x, __ptr, "l", "ir", label); \ break; \ case 8: \ - __put_user_asm_ex_u64((__typeof__(*ptr))(x), ptr); \ + __put_user_goto_u64(__x, __ptr, label); \ break; \ default: \ __put_user_bad(); \ } \ + instrument_put_user(__x, __ptr, size); \ } while (0) +#ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT + #ifdef CONFIG_X86_32 -#define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad() -#define __get_user_asm_ex_u64(x, ptr) (x) = __get_user_bad() +#define __get_user_asm_u64(x, ptr, label) do { \ + unsigned int __gu_low, __gu_high; \ + const unsigned int __user *__gu_ptr; \ + __gu_ptr = (const void __user *)(ptr); \ + __get_user_asm(__gu_low, __gu_ptr, "l", "=r", label); \ + __get_user_asm(__gu_high, __gu_ptr+1, "l", "=r", label); \ + (x) = ((unsigned long long)__gu_high << 32) | __gu_low; \ +} while (0) #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") +#define __get_user_asm_u64(x, ptr, label) \ + __get_user_asm(x, ptr, "q", "=r", label) #endif -#define __get_user_size(x, ptr, size, retval, errret) \ +#define __get_user_size(x, ptr, size, label) \ do { \ - retval = 0; \ __chk_user_ptr(ptr); \ switch (size) { \ - case 1: \ - __get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \ + case 1: { \ + unsigned char x_u8__; \ + __get_user_asm(x_u8__, ptr, "b", "=q", label); \ + (x) = x_u8__; \ break; \ + } \ case 2: \ - __get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \ + __get_user_asm(x, ptr, "w", "=r", label); \ break; \ case 4: \ - __get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \ + __get_user_asm(x, ptr, "l", "=r", label); \ break; \ case 8: \ - __get_user_asm_u64(x, ptr, retval, errret); \ + __get_user_asm_u64(x, ptr, label); \ break; \ default: \ (x) = __get_user_bad(); \ } \ + instrument_get_user(x); \ } while (0) -#define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \ - asm volatile(ASM_STAC "\n" \ - "1: mov"itype" %2,%"rtype"1\n" \ - "2: " ASM_CLAC "\n" \ - ".section .fixup,\"ax\"\n" \ - "3: mov %3,%0\n" \ - " xor"itype" %"rtype"1,%"rtype"1\n" \ - " jmp 2b\n" \ - ".previous\n" \ - _ASM_EXTABLE(1b, 3b) \ - : "=r" (err), ltype(x) \ - : "m" (__m(addr)), "i" (errret), "0" (err)) - -#define __get_user_size_ex(x, ptr, size) \ +#define __get_user_asm(x, addr, itype, ltype, label) \ + asm_goto_output("\n" \ + "1: mov"itype" %[umem],%[output]\n" \ + _ASM_EXTABLE_UA(1b, %l2) \ + : [output] ltype(x) \ + : [umem] "m" (__m(addr)) \ + : : label) + +#else // !CONFIG_CC_HAS_ASM_GOTO_OUTPUT + +#ifdef CONFIG_X86_32 +#define __get_user_asm_u64(x, ptr, retval) \ +({ \ + __typeof__(ptr) __ptr = (ptr); \ + asm volatile("\n" \ + "1: movl %[lowbits],%%eax\n" \ + "2: movl %[highbits],%%edx\n" \ + "3:\n" \ + _ASM_EXTABLE_TYPE_REG(1b, 3b, EX_TYPE_EFAULT_REG | \ + EX_FLAG_CLEAR_AX_DX, \ + %[errout]) \ + _ASM_EXTABLE_TYPE_REG(2b, 3b, EX_TYPE_EFAULT_REG | \ + EX_FLAG_CLEAR_AX_DX, \ + %[errout]) \ + : [errout] "=r" (retval), \ + [output] "=&A"(x) \ + : [lowbits] "m" (__m(__ptr)), \ + [highbits] "m" __m(((u32 __user *)(__ptr)) + 1), \ + "0" (retval)); \ +}) + +#else +#define __get_user_asm_u64(x, ptr, retval) \ + __get_user_asm(x, ptr, retval, "q") +#endif + +#define __get_user_size(x, ptr, size, retval) \ do { \ + unsigned char x_u8__; \ + \ + retval = 0; \ __chk_user_ptr(ptr); \ switch (size) { \ case 1: \ - __get_user_asm_ex(x, ptr, "b", "b", "=q"); \ + __get_user_asm(x_u8__, ptr, retval, "b"); \ + (x) = x_u8__; \ break; \ case 2: \ - __get_user_asm_ex(x, ptr, "w", "w", "=r"); \ + __get_user_asm(x, ptr, retval, "w"); \ break; \ case 4: \ - __get_user_asm_ex(x, ptr, "l", "k", "=r"); \ + __get_user_asm(x, ptr, retval, "l"); \ break; \ case 8: \ - __get_user_asm_ex_u64(x, ptr); \ + __get_user_asm_u64(x, ptr, retval); \ 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" \ +#define __get_user_asm(x, addr, err, itype) \ + asm volatile("\n" \ + "1: mov"itype" %[umem],%[output]\n" \ "2:\n" \ - _ASM_EXTABLE_EX(1b, 2b) \ - : ltype(x) : "m" (__m(addr))) - -#define __put_user_nocheck(x, ptr, size) \ -({ \ - int __pu_err; \ - __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \ - __pu_err; \ -}) + _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG | \ + EX_FLAG_CLEAR_AX, \ + %[errout]) \ + : [errout] "=r" (err), \ + [output] "=a" (x) \ + : [umem] "m" (__m(addr)), \ + "0" (err)) + +#endif // CONFIG_CC_HAS_ASM_GOTO_OUTPUT + +#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_goto_output("\n" \ + "1: " LOCK_PREFIX "cmpxchg"itype" %[new], %[ptr]\n"\ + _ASM_EXTABLE_UA(1b, %l[label]) \ + : "=@ccz" (success), \ + [ptr] "+m" (*_ptr), \ + [old] "+a" (__old) \ + : [new] ltype (__new) \ + : "memory" \ + : label); \ + if (unlikely(!success)) \ + *_old = __old; \ + likely(success); }) -#define __get_user_nocheck(x, ptr, size) \ -({ \ - int __gu_err; \ - unsigned long __gu_val; \ - __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \ - (x) = (__force __typeof__(*(ptr)))__gu_val; \ - __gu_err; \ -}) +#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_goto_output("\n" \ + "1: " LOCK_PREFIX "cmpxchg8b %[ptr]\n" \ + _ASM_EXTABLE_UA(1b, %l[label]) \ + : "=@ccz" (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"\ + "2:\n" \ + _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, \ + %[errout]) \ + : "=@ccz" (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, use output GPR 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, %[result]\n\t" \ + "setz %b[result]\n" \ + "2:\n" \ + _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, \ + %[result]) \ + : [result] "=q" (__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]; }; @@ -408,119 +475,28 @@ struct __large_struct { unsigned long buf[100]; }; * we do not write to any memory gcc knows about, so there are no * aliasing issues. */ -#define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \ - asm volatile(ASM_STAC "\n" \ - "1: mov"itype" %"rtype"1,%2\n" \ - "2: " ASM_CLAC "\n" \ - ".section .fixup,\"ax\"\n" \ - "3: mov %3,%0\n" \ - " jmp 2b\n" \ - ".previous\n" \ - _ASM_EXTABLE(1b, 3b) \ - : "=r"(err) \ - : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err)) - -#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_info()->uaccess_err = 0; \ - stac(); \ - barrier(); - -#define uaccess_catch(err) \ - clac(); \ - (err) |= (current_thread_info()->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. - * - * 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. - * - * Returns 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. - * - * 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. - * - * Returns zero on success, or -EFAULT on error. - */ - -#define __put_user(x, ptr) \ - __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) - -#define __get_user_unaligned __get_user -#define __put_user_unaligned __put_user - -/* - * {get|put}_user_try and catch - * - * get_user_try { - * get_user_ex(...); - * } get_user_catch(err) - */ -#define get_user_try uaccess_try -#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))) +#define __put_user_goto(x, addr, itype, ltype, label) \ + asm goto("\n" \ + "1: mov"itype" %0,%1\n" \ + _ASM_EXTABLE_UA(1b, %l2) \ + : : ltype(x), "m" (__m(addr)) \ + : : label) 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 strlen_user(const char __user *str); 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); +#ifdef CONFIG_ARCH_HAS_COPY_MC +unsigned long __must_check +copy_mc_to_kernel(void *to, const void *from, unsigned len); +#define copy_mc_to_kernel copy_mc_to_kernel + +unsigned long __must_check +copy_mc_to_user(void __user *to, const void *from, unsigned len); +#endif /* * movsl can be slow when source and dest are not both 8-byte aligned @@ -533,11 +509,133 @@ extern struct movsl_mask { #define ARCH_HAS_NOCACHE_UACCESS 1 -#ifdef CONFIG_X86_32 -# include <asm/uaccess_32.h> -#else -# include <asm/uaccess_64.h> +/* + * 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 arch_unsafe_put_user(x, ptr, label) \ + __put_user_size((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)), label) + +#ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT +#define arch_unsafe_get_user(x, ptr, err_label) \ +do { \ + __inttype(*(ptr)) __gu_val; \ + __get_user_size(__gu_val, (ptr), sizeof(*(ptr)), err_label); \ + (x) = (__force __typeof__(*(ptr)))__gu_val; \ +} while (0) +#else // !CONFIG_CC_HAS_ASM_GOTO_OUTPUT +#define arch_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); \ + (x) = (__force __typeof__(*(ptr)))__gu_val; \ + if (unlikely(__gu_err)) goto err_label; \ +} while (0) +#endif // CONFIG_CC_HAS_ASM_GOTO_OUTPUT + +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) + +#ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT +#define arch_get_kernel_nofault(dst, src, type, err_label) \ + __get_user_size(*((type *)(dst)), (__force type __user *)(src), \ + sizeof(type), err_label) +#else // !CONFIG_CC_HAS_ASM_GOTO_OUTPUT +#define arch_get_kernel_nofault(dst, src, type, err_label) \ +do { \ + int __kr_err; \ + \ + __get_user_size(*((type *)(dst)), (__force type __user *)(src), \ + sizeof(type), __kr_err); \ + if (unlikely(__kr_err)) \ + goto err_label; \ +} while (0) +#endif // CONFIG_CC_HAS_ASM_GOTO_OUTPUT + +#define arch_put_kernel_nofault(dst, src, type, err_label) \ + __put_user_size(*((type *)(src)), (__force type __user *)(dst), \ + sizeof(type), err_label) + #endif /* _ASM_X86_UACCESS_H */ |