174 lines
4.2 KiB
ArmAsm
174 lines
4.2 KiB
ArmAsm
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/*
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* linux/arch/arm26/lib/uaccess-kernel.S
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*
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* Copyright (C) 1998 Russell King
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*
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* Note! Some code fragments found in here have a special calling
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* convention - they are not APCS compliant!
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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.text
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//FIXME - surely this can be done in C not asm, removing the problem of keeping C and asm in sync? (this is a struct uaccess_t)
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.globl uaccess_kernel
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uaccess_kernel:
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.word uaccess_kernel_put_byte
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.word uaccess_kernel_get_byte
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.word uaccess_kernel_put_half
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.word uaccess_kernel_get_half
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.word uaccess_kernel_put_word
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.word uaccess_kernel_get_word
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.word uaccess_kernel_put_dword
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.word uaccess_kernel_copy
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.word uaccess_kernel_copy
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.word uaccess_kernel_clear
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.word uaccess_kernel_strncpy
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.word uaccess_kernel_strnlen
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@ In : r0 = x, r1 = addr, r2 = error
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@ Out: r2 = error
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uaccess_kernel_put_byte:
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stmfd sp!, {lr}
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strb r0, [r1]
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ldmfd sp!, {pc}^
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@ In : r0 = x, r1 = addr, r2 = error
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@ Out: r2 = error
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uaccess_kernel_put_half:
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stmfd sp!, {lr}
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strb r0, [r1]
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mov r0, r0, lsr #8
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strb r0, [r1, #1]
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ldmfd sp!, {pc}^
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@ In : r0 = x, r1 = addr, r2 = error
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@ Out: r2 = error
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uaccess_kernel_put_word:
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stmfd sp!, {lr}
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str r0, [r1]
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ldmfd sp!, {pc}^
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@ In : r0 = x, r1 = addr, r2 = error
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@ Out: r2 = error
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uaccess_kernel_put_dword:
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stmfd sp!, {lr}
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str r0, [r1], #4
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str r0, [r1], #0
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ldmfd sp!, {pc}^
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@ In : r0 = addr, r1 = error
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@ Out: r0 = x, r1 = error
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uaccess_kernel_get_byte:
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stmfd sp!, {lr}
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ldrb r0, [r0]
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ldmfd sp!, {pc}^
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@ In : r0 = addr, r1 = error
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@ Out: r0 = x, r1 = error
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uaccess_kernel_get_half:
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stmfd sp!, {lr}
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ldr r0, [r0]
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mov r0, r0, lsl #16
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mov r0, r0, lsr #16
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ldmfd sp!, {pc}^
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@ In : r0 = addr, r1 = error
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@ Out: r0 = x, r1 = error
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uaccess_kernel_get_word:
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stmfd sp!, {lr}
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ldr r0, [r0]
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ldmfd sp!, {pc}^
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/* Prototype: int uaccess_kernel_copy(void *to, const char *from, size_t n)
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* Purpose : copy a block to kernel memory from kernel memory
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* Params : to - kernel memory
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* : from - kernel memory
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* : n - number of bytes to copy
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* Returns : Number of bytes NOT copied.
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*/
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uaccess_kernel_copy:
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stmfd sp!, {lr}
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bl memcpy
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mov r0, #0
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ldmfd sp!, {pc}^
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/* Prototype: int uaccess_kernel_clear(void *addr, size_t sz)
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* Purpose : clear some kernel memory
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* Params : addr - kernel memory address to clear
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* : sz - number of bytes to clear
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* Returns : number of bytes NOT cleared
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*/
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uaccess_kernel_clear:
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stmfd sp!, {lr}
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mov r2, #0
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cmp r1, #4
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blt 2f
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ands ip, r0, #3
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beq 1f
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cmp ip, #1
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strb r2, [r0], #1
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strleb r2, [r0], #1
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strltb r2, [r0], #1
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rsb ip, ip, #4
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sub r1, r1, ip @ 7 6 5 4 3 2 1
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1: subs r1, r1, #8 @ -1 -2 -3 -4 -5 -6 -7
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bmi 2f
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str r2, [r0], #4
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str r2, [r0], #4
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b 1b
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2: adds r1, r1, #4 @ 3 2 1 0 -1 -2 -3
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strpl r2, [r0], #4
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tst r1, #2 @ 1x 1x 0x 0x 1x 1x 0x
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strneb r2, [r0], #1
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strneb r2, [r0], #1
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tst r1, #1 @ x1 x0 x1 x0 x1 x0 x1
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strneb r2, [r0], #1
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mov r0, #0
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ldmfd sp!, {pc}^
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/* Prototype: size_t uaccess_kernel_strncpy(char *dst, char *src, size_t len)
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* Purpose : copy a string from kernel memory to kernel memory
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* Params : dst - kernel memory destination
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* : src - kernel memory source
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* : len - maximum length of string
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* Returns : number of characters copied
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*/
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uaccess_kernel_strncpy:
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stmfd sp!, {lr}
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mov ip, r2
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1: subs r2, r2, #1
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bmi 2f
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ldrb r3, [r1], #1
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strb r3, [r0], #1
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teq r3, #0
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bne 1b
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2: subs r0, ip, r2
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ldmfd sp!, {pc}^
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/* Prototype: int uaccess_kernel_strlen(char *str, long n)
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* Purpose : get length of a string in kernel memory
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* Params : str - address of string in kernel memory
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* Returns : length of string *including terminator*,
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* or zero on exception, or n + 1 if too long
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*/
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uaccess_kernel_strnlen:
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stmfd sp!, {lr}
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mov r2, r0
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1: ldrb r1, [r0], #1
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teq r1, #0
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beq 2f
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subs r1, r1, #1
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bne 1b
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add r0, r0, #1
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2: sub r0, r0, r2
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ldmfd sp!, {pc}^
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