/* * linux/arch/arm26/lib/uaccess-user.S * * Copyright (C) 1995, 1996,1997,1998 Russell King * * 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. * * Routines to block copy data to/from user memory * These are highly optimised both for the 4k page size * and for various alignments. */ #include <linux/linkage.h> #include <asm/assembler.h> #include <asm/errno.h> #include <asm/page.h> .text //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) .globl uaccess_user uaccess_user: .word uaccess_user_put_byte .word uaccess_user_get_byte .word uaccess_user_put_half .word uaccess_user_get_half .word uaccess_user_put_word .word uaccess_user_get_word .word uaccess_user_put_dword .word uaccess_user_copy_from_user .word uaccess_user_copy_to_user .word uaccess_user_clear_user .word uaccess_user_strncpy_from_user .word uaccess_user_strnlen_user @ In : r0 = x, r1 = addr, r2 = error @ Out: r2 = error uaccess_user_put_byte: stmfd sp!, {lr} USER( strbt r0, [r1]) ldmfd sp!, {pc}^ @ In : r0 = x, r1 = addr, r2 = error @ Out: r2 = error uaccess_user_put_half: stmfd sp!, {lr} USER( strbt r0, [r1], #1) mov r0, r0, lsr #8 USER( strbt r0, [r1]) ldmfd sp!, {pc}^ @ In : r0 = x, r1 = addr, r2 = error @ Out: r2 = error uaccess_user_put_word: stmfd sp!, {lr} USER( strt r0, [r1]) ldmfd sp!, {pc}^ @ In : r0 = x, r1 = addr, r2 = error @ Out: r2 = error uaccess_user_put_dword: stmfd sp!, {lr} USER( strt r0, [r1], #4) USER( strt r0, [r1], #0) ldmfd sp!, {pc}^ 9001: mov r2, #-EFAULT ldmfd sp!, {pc}^ @ In : r0 = addr, r1 = error @ Out: r0 = x, r1 = error uaccess_user_get_byte: stmfd sp!, {lr} USER( ldrbt r0, [r0]) ldmfd sp!, {pc}^ @ In : r0 = addr, r1 = error @ Out: r0 = x, r1 = error uaccess_user_get_half: stmfd sp!, {lr} USER( ldrt r0, [r0]) mov r0, r0, lsl #16 mov r0, r0, lsr #16 ldmfd sp!, {pc}^ @ In : r0 = addr, r1 = error @ Out: r0 = x, r1 = error uaccess_user_get_word: stmfd sp!, {lr} USER( ldrt r0, [r0]) ldmfd sp!, {pc}^ 9001: mov r1, #-EFAULT ldmfd sp!, {pc}^ /* Prototype: int uaccess_user_copy_to_user(void *to, const char *from, size_t n) * Purpose : copy a block to user memory from kernel memory * Params : to - user memory * : from - kernel memory * : n - number of bytes to copy * Returns : Number of bytes NOT copied. */ .c2u_dest_not_aligned: rsb ip, ip, #4 cmp ip, #2 ldrb r3, [r1], #1 USER( strbt r3, [r0], #1) @ May fault ldrgeb r3, [r1], #1 USER( strgebt r3, [r0], #1) @ May fault ldrgtb r3, [r1], #1 USER( strgtbt r3, [r0], #1) @ May fault sub r2, r2, ip b .c2u_dest_aligned ENTRY(uaccess_user_copy_to_user) stmfd sp!, {r2, r4 - r7, lr} cmp r2, #4 blt .c2u_not_enough ands ip, r0, #3 bne .c2u_dest_not_aligned .c2u_dest_aligned: ands ip, r1, #3 bne .c2u_src_not_aligned /* * Seeing as there has to be at least 8 bytes to copy, we can * copy one word, and force a user-mode page fault... */ .c2u_0fupi: subs r2, r2, #4 addmi ip, r2, #4 bmi .c2u_0nowords ldr r3, [r1], #4 USER( strt r3, [r0], #4) @ May fault mov ip, r0, lsl #32 - PAGE_SHIFT @ On each page, use a ld/st??t instruction rsb ip, ip, #0 movs ip, ip, lsr #32 - PAGE_SHIFT beq .c2u_0fupi /* * ip = max no. of bytes to copy before needing another "strt" insn */ cmp r2, ip movlt ip, r2 sub r2, r2, ip subs ip, ip, #32 blt .c2u_0rem8lp .c2u_0cpy8lp: ldmia r1!, {r3 - r6} stmia r0!, {r3 - r6} @ Shouldnt fault ldmia r1!, {r3 - r6} stmia r0!, {r3 - r6} @ Shouldnt fault subs ip, ip, #32 bpl .c2u_0cpy8lp .c2u_0rem8lp: cmn ip, #16 ldmgeia r1!, {r3 - r6} stmgeia r0!, {r3 - r6} @ Shouldnt fault tst ip, #8 ldmneia r1!, {r3 - r4} stmneia r0!, {r3 - r4} @ Shouldnt fault tst ip, #4 ldrne r3, [r1], #4 strnet r3, [r0], #4 @ Shouldnt fault ands ip, ip, #3 beq .c2u_0fupi .c2u_0nowords: teq ip, #0 beq .c2u_finished .c2u_nowords: cmp ip, #2 ldrb r3, [r1], #1 USER( strbt r3, [r0], #1) @ May fault ldrgeb r3, [r1], #1 USER( strgebt r3, [r0], #1) @ May fault ldrgtb r3, [r1], #1 USER( strgtbt r3, [r0], #1) @ May fault b .c2u_finished .c2u_not_enough: movs ip, r2 bne .c2u_nowords .c2u_finished: mov r0, #0 LOADREGS(fd,sp!,{r2, r4 - r7, pc}) .c2u_src_not_aligned: bic r1, r1, #3 ldr r7, [r1], #4 cmp ip, #2 bgt .c2u_3fupi beq .c2u_2fupi .c2u_1fupi: subs r2, r2, #4 addmi ip, r2, #4 bmi .c2u_1nowords mov r3, r7, pull #8 ldr r7, [r1], #4 orr r3, r3, r7, push #24 USER( strt r3, [r0], #4) @ May fault mov ip, r0, lsl #32 - PAGE_SHIFT rsb ip, ip, #0 movs ip, ip, lsr #32 - PAGE_SHIFT beq .c2u_1fupi cmp r2, ip movlt ip, r2 sub r2, r2, ip subs ip, ip, #16 blt .c2u_1rem8lp .c2u_1cpy8lp: mov r3, r7, pull #8 ldmia r1!, {r4 - r7} orr r3, r3, r4, push #24 mov r4, r4, pull #8 orr r4, r4, r5, push #24 mov r5, r5, pull #8 orr r5, r5, r6, push #24 mov r6, r6, pull #8 orr r6, r6, r7, push #24 stmia r0!, {r3 - r6} @ Shouldnt fault subs ip, ip, #16 bpl .c2u_1cpy8lp .c2u_1rem8lp: tst ip, #8 movne r3, r7, pull #8 ldmneia r1!, {r4, r7} orrne r3, r3, r4, push #24 movne r4, r4, pull #8 orrne r4, r4, r7, push #24 stmneia r0!, {r3 - r4} @ Shouldnt fault tst ip, #4 movne r3, r7, pull #8 ldrne r7, [r1], #4 orrne r3, r3, r7, push #24 strnet r3, [r0], #4 @ Shouldnt fault ands ip, ip, #3 beq .c2u_1fupi .c2u_1nowords: mov r3, r7, lsr #byte(1) teq ip, #0 beq .c2u_finished cmp ip, #2 USER( strbt r3, [r0], #1) @ May fault movge r3, r7, lsr #byte(2) USER( strgebt r3, [r0], #1) @ May fault movgt r3, r7, lsr #byte(3) USER( strgtbt r3, [r0], #1) @ May fault b .c2u_finished .c2u_2fupi: subs r2, r2, #4 addmi ip, r2, #4 bmi .c2u_2nowords mov r3, r7, pull #16 ldr r7, [r1], #4 orr r3, r3, r7, push #16 USER( strt r3, [r0], #4) @ May fault mov ip, r0, lsl #32 - PAGE_SHIFT rsb ip, ip, #0 movs ip, ip, lsr #32 - PAGE_SHIFT beq .c2u_2fupi cmp r2, ip movlt ip, r2 sub r2, r2, ip subs ip, ip, #16 blt .c2u_2rem8lp .c2u_2cpy8lp: mov r3, r7, pull #16 ldmia r1!, {r4 - r7} orr r3, r3, r4, push #16 mov r4, r4, pull #16 orr r4, r4, r5, push #16 mov r5, r5, pull #16 orr r5, r5, r6, push #16 mov r6, r6, pull #16 orr r6, r6, r7, push #16 stmia r0!, {r3 - r6} @ Shouldnt fault subs ip, ip, #16 bpl .c2u_2cpy8lp .c2u_2rem8lp: tst ip, #8 movne r3, r7, pull #16 ldmneia r1!, {r4, r7} orrne r3, r3, r4, push #16 movne r4, r4, pull #16 orrne r4, r4, r7, push #16 stmneia r0!, {r3 - r4} @ Shouldnt fault tst ip, #4 movne r3, r7, pull #16 ldrne r7, [r1], #4 orrne r3, r3, r7, push #16 strnet r3, [r0], #4 @ Shouldnt fault ands ip, ip, #3 beq .c2u_2fupi .c2u_2nowords: mov r3, r7, lsr #byte(2) teq ip, #0 beq .c2u_finished cmp ip, #2 USER( strbt r3, [r0], #1) @ May fault movge r3, r7, lsr #byte(3) USER( strgebt r3, [r0], #1) @ May fault ldrgtb r3, [r1], #0 USER( strgtbt r3, [r0], #1) @ May fault b .c2u_finished .c2u_3fupi: subs r2, r2, #4 addmi ip, r2, #4 bmi .c2u_3nowords mov r3, r7, pull #24 ldr r7, [r1], #4 orr r3, r3, r7, push #8 USER( strt r3, [r0], #4) @ May fault mov ip, r0, lsl #32 - PAGE_SHIFT rsb ip, ip, #0 movs ip, ip, lsr #32 - PAGE_SHIFT beq .c2u_3fupi cmp r2, ip movlt ip, r2 sub r2, r2, ip subs ip, ip, #16 blt .c2u_3rem8lp .c2u_3cpy8lp: mov r3, r7, pull #24 ldmia r1!, {r4 - r7} orr r3, r3, r4, push #8 mov r4, r4, pull #24 orr r4, r4, r5, push #8 mov r5, r5, pull #24 orr r5, r5, r6, push #8 mov r6, r6, pull #24 orr r6, r6, r7, push #8 stmia r0!, {r3 - r6} @ Shouldnt fault subs ip, ip, #16 bpl .c2u_3cpy8lp .c2u_3rem8lp: tst ip, #8 movne r3, r7, pull #24 ldmneia r1!, {r4, r7} orrne r3, r3, r4, push #8 movne r4, r4, pull #24 orrne r4, r4, r7, push #8 stmneia r0!, {r3 - r4} @ Shouldnt fault tst ip, #4 movne r3, r7, pull #24 ldrne r7, [r1], #4 orrne r3, r3, r7, push #8 strnet r3, [r0], #4 @ Shouldnt fault ands ip, ip, #3 beq .c2u_3fupi .c2u_3nowords: mov r3, r7, lsr #byte(3) teq ip, #0 beq .c2u_finished cmp ip, #2 USER( strbt r3, [r0], #1) @ May fault ldrgeb r3, [r1], #1 USER( strgebt r3, [r0], #1) @ May fault ldrgtb r3, [r1], #0 USER( strgtbt r3, [r0], #1) @ May fault b .c2u_finished .section .fixup,"ax" .align 0 9001: LOADREGS(fd,sp!, {r0, r4 - r7, pc}) .previous /* Prototype: unsigned long uaccess_user_copy_from_user(void *to,const void *from,unsigned long n); * Purpose : copy a block from user memory to kernel memory * Params : to - kernel memory * : from - user memory * : n - number of bytes to copy * Returns : Number of bytes NOT copied. */ .cfu_dest_not_aligned: rsb ip, ip, #4 cmp ip, #2 USER( ldrbt r3, [r1], #1) @ May fault strb r3, [r0], #1 USER( ldrgebt r3, [r1], #1) @ May fault strgeb r3, [r0], #1 USER( ldrgtbt r3, [r1], #1) @ May fault strgtb r3, [r0], #1 sub r2, r2, ip b .cfu_dest_aligned ENTRY(uaccess_user_copy_from_user) stmfd sp!, {r0, r2, r4 - r7, lr} cmp r2, #4 blt .cfu_not_enough ands ip, r0, #3 bne .cfu_dest_not_aligned .cfu_dest_aligned: ands ip, r1, #3 bne .cfu_src_not_aligned /* * Seeing as there has to be at least 8 bytes to copy, we can * copy one word, and force a user-mode page fault... */ .cfu_0fupi: subs r2, r2, #4 addmi ip, r2, #4 bmi .cfu_0nowords USER( ldrt r3, [r1], #4) str r3, [r0], #4 mov ip, r1, lsl #32 - PAGE_SHIFT @ On each page, use a ld/st??t instruction rsb ip, ip, #0 movs ip, ip, lsr #32 - PAGE_SHIFT beq .cfu_0fupi /* * ip = max no. of bytes to copy before needing another "strt" insn */ cmp r2, ip movlt ip, r2 sub r2, r2, ip subs ip, ip, #32 blt .cfu_0rem8lp .cfu_0cpy8lp: ldmia r1!, {r3 - r6} @ Shouldnt fault stmia r0!, {r3 - r6} ldmia r1!, {r3 - r6} @ Shouldnt fault stmia r0!, {r3 - r6} subs ip, ip, #32 bpl .cfu_0cpy8lp .cfu_0rem8lp: cmn ip, #16 ldmgeia r1!, {r3 - r6} @ Shouldnt fault stmgeia r0!, {r3 - r6} tst ip, #8 ldmneia r1!, {r3 - r4} @ Shouldnt fault stmneia r0!, {r3 - r4} tst ip, #4 ldrnet r3, [r1], #4 @ Shouldnt fault strne r3, [r0], #4 ands ip, ip, #3 beq .cfu_0fupi .cfu_0nowords: teq ip, #0 beq .cfu_finished .cfu_nowords: cmp ip, #2 USER( ldrbt r3, [r1], #1) @ May fault strb r3, [r0], #1 USER( ldrgebt r3, [r1], #1) @ May fault strgeb r3, [r0], #1 USER( ldrgtbt r3, [r1], #1) @ May fault strgtb r3, [r0], #1 b .cfu_finished .cfu_not_enough: movs ip, r2 bne .cfu_nowords .cfu_finished: mov r0, #0 add sp, sp, #8 LOADREGS(fd,sp!,{r4 - r7, pc}) .cfu_src_not_aligned: bic r1, r1, #3 USER( ldrt r7, [r1], #4) @ May fault cmp ip, #2 bgt .cfu_3fupi beq .cfu_2fupi .cfu_1fupi: subs r2, r2, #4 addmi ip, r2, #4 bmi .cfu_1nowords mov r3, r7, pull #8 USER( ldrt r7, [r1], #4) @ May fault orr r3, r3, r7, push #24 str r3, [r0], #4 mov ip, r1, lsl #32 - PAGE_SHIFT rsb ip, ip, #0 movs ip, ip, lsr #32 - PAGE_SHIFT beq .cfu_1fupi cmp r2, ip movlt ip, r2 sub r2, r2, ip subs ip, ip, #16 blt .cfu_1rem8lp .cfu_1cpy8lp: mov r3, r7, pull #8 ldmia r1!, {r4 - r7} @ Shouldnt fault orr r3, r3, r4, push #24 mov r4, r4, pull #8 orr r4, r4, r5, push #24 mov r5, r5, pull #8 orr r5, r5, r6, push #24 mov r6, r6, pull #8 orr r6, r6, r7, push #24 stmia r0!, {r3 - r6} subs ip, ip, #16 bpl .cfu_1cpy8lp .cfu_1rem8lp: tst ip, #8 movne r3, r7, pull #8 ldmneia r1!, {r4, r7} @ Shouldnt fault orrne r3, r3, r4, push #24 movne r4, r4, pull #8 orrne r4, r4, r7, push #24 stmneia r0!, {r3 - r4} tst ip, #4 movne r3, r7, pull #8 USER( ldrnet r7, [r1], #4) @ May fault orrne r3, r3, r7, push #24 strne r3, [r0], #4 ands ip, ip, #3 beq .cfu_1fupi .cfu_1nowords: mov r3, r7, lsr #byte(1) teq ip, #0 beq .cfu_finished cmp ip, #2 strb r3, [r0], #1 movge r3, r7, lsr #byte(2) strgeb r3, [r0], #1 movgt r3, r7, lsr #byte(3) strgtb r3, [r0], #1 b .cfu_finished .cfu_2fupi: subs r2, r2, #4 addmi ip, r2, #4 bmi .cfu_2nowords mov r3, r7, pull #16 USER( ldrt r7, [r1], #4) @ May fault orr r3, r3, r7, push #16 str r3, [r0], #4 mov ip, r1, lsl #32 - PAGE_SHIFT rsb ip, ip, #0 movs ip, ip, lsr #32 - PAGE_SHIFT beq .cfu_2fupi cmp r2, ip movlt ip, r2 sub r2, r2, ip subs ip, ip, #16 blt .cfu_2rem8lp .cfu_2cpy8lp: mov r3, r7, pull #16 ldmia r1!, {r4 - r7} @ Shouldnt fault orr r3, r3, r4, push #16 mov r4, r4, pull #16 orr r4, r4, r5, push #16 mov r5, r5, pull #16 orr r5, r5, r6, push #16 mov r6, r6, pull #16 orr r6, r6, r7, push #16 stmia r0!, {r3 - r6} subs ip, ip, #16 bpl .cfu_2cpy8lp .cfu_2rem8lp: tst ip, #8 movne r3, r7, pull #16 ldmneia r1!, {r4, r7} @ Shouldnt fault orrne r3, r3, r4, push #16 movne r4, r4, pull #16 orrne r4, r4, r7, push #16 stmneia r0!, {r3 - r4} tst ip, #4 movne r3, r7, pull #16 USER( ldrnet r7, [r1], #4) @ May fault orrne r3, r3, r7, push #16 strne r3, [r0], #4 ands ip, ip, #3 beq .cfu_2fupi .cfu_2nowords: mov r3, r7, lsr #byte(2) teq ip, #0 beq .cfu_finished cmp ip, #2 strb r3, [r0], #1 movge r3, r7, lsr #byte(3) strgeb r3, [r0], #1 USER( ldrgtbt r3, [r1], #0) @ May fault strgtb r3, [r0], #1 b .cfu_finished .cfu_3fupi: subs r2, r2, #4 addmi ip, r2, #4 bmi .cfu_3nowords mov r3, r7, pull #24 USER( ldrt r7, [r1], #4) @ May fault orr r3, r3, r7, push #8 str r3, [r0], #4 mov ip, r1, lsl #32 - PAGE_SHIFT rsb ip, ip, #0 movs ip, ip, lsr #32 - PAGE_SHIFT beq .cfu_3fupi cmp r2, ip movlt ip, r2 sub r2, r2, ip subs ip, ip, #16 blt .cfu_3rem8lp .cfu_3cpy8lp: mov r3, r7, pull #24 ldmia r1!, {r4 - r7} @ Shouldnt fault orr r3, r3, r4, push #8 mov r4, r4, pull #24 orr r4, r4, r5, push #8 mov r5, r5, pull #24 orr r5, r5, r6, push #8 mov r6, r6, pull #24 orr r6, r6, r7, push #8 stmia r0!, {r3 - r6} subs ip, ip, #16 bpl .cfu_3cpy8lp .cfu_3rem8lp: tst ip, #8 movne r3, r7, pull #24 ldmneia r1!, {r4, r7} @ Shouldnt fault orrne r3, r3, r4, push #8 movne r4, r4, pull #24 orrne r4, r4, r7, push #8 stmneia r0!, {r3 - r4} tst ip, #4 movne r3, r7, pull #24 USER( ldrnet r7, [r1], #4) @ May fault orrne r3, r3, r7, push #8 strne r3, [r0], #4 ands ip, ip, #3 beq .cfu_3fupi .cfu_3nowords: mov r3, r7, lsr #byte(3) teq ip, #0 beq .cfu_finished cmp ip, #2 strb r3, [r0], #1 USER( ldrgebt r3, [r1], #1) @ May fault strgeb r3, [r0], #1 USER( ldrgtbt r3, [r1], #1) @ May fault strgtb r3, [r0], #1 b .cfu_finished .section .fixup,"ax" .align 0 /* * We took an exception. r0 contains a pointer to * the byte not copied. */ 9001: ldr r2, [sp], #4 @ void *to sub r2, r0, r2 @ bytes copied ldr r1, [sp], #4 @ unsigned long count subs r4, r1, r2 @ bytes left to copy movne r1, r4 blne __memzero mov r0, r4 LOADREGS(fd,sp!, {r4 - r7, pc}) .previous /* Prototype: int uaccess_user_clear_user(void *addr, size_t sz) * Purpose : clear some user memory * Params : addr - user memory address to clear * : sz - number of bytes to clear * Returns : number of bytes NOT cleared */ ENTRY(uaccess_user_clear_user) stmfd sp!, {r1, lr} mov r2, #0 cmp r1, #4 blt 2f ands ip, r0, #3 beq 1f cmp ip, #2 USER( strbt r2, [r0], #1) USER( strlebt r2, [r0], #1) USER( strltbt r2, [r0], #1) rsb ip, ip, #4 sub r1, r1, ip @ 7 6 5 4 3 2 1 1: subs r1, r1, #8 @ -1 -2 -3 -4 -5 -6 -7 USER( strplt r2, [r0], #4) USER( strplt r2, [r0], #4) bpl 1b adds r1, r1, #4 @ 3 2 1 0 -1 -2 -3 USER( strplt r2, [r0], #4) 2: tst r1, #2 @ 1x 1x 0x 0x 1x 1x 0x USER( strnebt r2, [r0], #1) USER( strnebt r2, [r0], #1) tst r1, #1 @ x1 x0 x1 x0 x1 x0 x1 USER( strnebt r2, [r0], #1) mov r0, #0 LOADREGS(fd,sp!, {r1, pc}) .section .fixup,"ax" .align 0 9001: LOADREGS(fd,sp!, {r0, pc}) .previous /* * Copy a string from user space to kernel space. * r0 = dst, r1 = src, r2 = byte length * returns the number of characters copied (strlen of copied string), * -EFAULT on exception, or "len" if we fill the whole buffer */ ENTRY(uaccess_user_strncpy_from_user) save_lr mov ip, r1 1: subs r2, r2, #1 USER( ldrplbt r3, [r1], #1) bmi 2f strb r3, [r0], #1 teq r3, #0 bne 1b sub r1, r1, #1 @ take NUL character out of count 2: sub r0, r1, ip restore_pc .section .fixup,"ax" .align 0 9001: mov r3, #0 strb r3, [r0, #0] @ null terminate mov r0, #-EFAULT restore_pc .previous /* Prototype: unsigned long uaccess_user_strnlen_user(const char *str, long n) * Purpose : get length of a string in user memory * Params : str - address of string in user memory * Returns : length of string *including terminator* * or zero on exception, or n + 1 if too long */ ENTRY(uaccess_user_strnlen_user) save_lr mov r2, r0 1: USER( ldrbt r3, [r0], #1) teq r3, #0 beq 2f subs r1, r1, #1 bne 1b add r0, r0, #1 2: sub r0, r0, r2 restore_pc .section .fixup,"ax" .align 0 9001: mov r0, #0 restore_pc .previous