1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * linux/arch/arm/lib/putuser.S 4 * 5 * Copyright (C) 2001 Russell King 6 * 7 * Idea from x86 version, (C) Copyright 1998 Linus Torvalds 8 * 9 * These functions have a non-standard call interface to make 10 * them more efficient, especially as they return an error 11 * value in addition to the "real" return value. 12 * 13 * __put_user_X 14 * 15 * Inputs: r0 contains the address 16 * r1 contains the address limit, which must be preserved 17 * r2, r3 contains the value 18 * Outputs: r0 is the error code 19 * lr corrupted 20 * 21 * No other registers must be altered. (see <asm/uaccess.h> 22 * for specific ASM register usage). 23 * 24 * Note that ADDR_LIMIT is either 0 or 0xc0000000 25 * Note also that it is intended that __put_user_bad is not global. 26 */ 27 #include <linux/linkage.h> 28 #include <asm/assembler.h> 29 #include <asm/errno.h> 30 #include <asm/domain.h> 31 32 ENTRY(__put_user_1) 33 check_uaccess r0, 1, r1, ip, __put_user_bad 34 1: TUSER(strb) r2, [r0] 35 mov r0, #0 36 ret lr 37 ENDPROC(__put_user_1) 38 39 ENTRY(__put_user_2) 40 check_uaccess r0, 2, r1, ip, __put_user_bad 41 #if __LINUX_ARM_ARCH__ >= 6 42 43 2: TUSER(strh) r2, [r0] 44 45 #else 46 47 mov ip, r2, lsr #8 48 #ifndef __ARMEB__ 49 2: TUSER(strb) r2, [r0], #1 50 3: TUSER(strb) ip, [r0] 51 #else 52 2: TUSER(strb) ip, [r0], #1 53 3: TUSER(strb) r2, [r0] 54 #endif 55 56 #endif /* __LINUX_ARM_ARCH__ >= 6 */ 57 mov r0, #0 58 ret lr 59 ENDPROC(__put_user_2) 60 61 ENTRY(__put_user_4) 62 check_uaccess r0, 4, r1, ip, __put_user_bad 63 4: TUSER(str) r2, [r0] 64 mov r0, #0 65 ret lr 66 ENDPROC(__put_user_4) 67 68 ENTRY(__put_user_8) 69 check_uaccess r0, 8, r1, ip, __put_user_bad 70 #ifdef CONFIG_THUMB2_KERNEL 71 5: TUSER(str) r2, [r0] 72 6: TUSER(str) r3, [r0, #4] 73 #else 74 5: TUSER(str) r2, [r0], #4 75 6: TUSER(str) r3, [r0] 76 #endif 77 mov r0, #0 78 ret lr 79 ENDPROC(__put_user_8) 80 81 __put_user_bad: 82 mov r0, #-EFAULT 83 ret lr 84 ENDPROC(__put_user_bad) 85 86 .pushsection __ex_table, "a" 87 .long 1b, __put_user_bad 88 .long 2b, __put_user_bad 89 #if __LINUX_ARM_ARCH__ < 6 90 .long 3b, __put_user_bad 91 #endif 92 .long 4b, __put_user_bad 93 .long 5b, __put_user_bad 94 .long 6b, __put_user_bad 95 .popsection 96