/*
* Copyright 2010 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#include <linux/linkage.h>
#include <asm/errno.h>
#include <asm/cache.h>
#include <arch/chip.h>
/* Access user memory, but use MMU to avoid propagating kernel exceptions. */
/*
* strnlen_user_asm takes the pointer in r0, and the length bound in r1.
* It returns the length, including the terminating NUL, or zero on exception.
* If length is greater than the bound, returns one plus the bound.
*/
STD_ENTRY(strnlen_user_asm)
{ bz r1, 2f; addi r3, r0, -1 } /* bias down to include NUL */
1: { lb_u r4, r0; addi r1, r1, -1 }
bz r4, 2f
{ bnzt r1, 1b; addi r0, r0, 1 }
2: { sub r0, r0, r3; jrp lr }
STD_ENDPROC(strnlen_user_asm)
.pushsection .fixup,"ax"
strnlen_user_fault:
{ move r0, zero; jrp lr }
ENDPROC(strnlen_user_fault)
.section __ex_table,"a"
.align 4
.word 1b, strnlen_user_fault
.popsection
/*
* strncpy_from_user_asm takes the kernel target pointer in r0,
* the userspace source pointer in r1, and the length bound (including
* the trailing NUL) in r2. On success, it returns the string length
* (not including the trailing NUL), or -EFAULT on failure.
*/
STD_ENTRY(strncpy_from_user_asm)
{ bz r2, 2f; move r3, r0 }
1: { lb_u r4, r1; addi r1, r1, 1; addi r2, r2, -1 }
{ sb r0, r4; addi r0, r0, 1 }
bz r4, 2f
bnzt r2, 1b
{ sub r0, r0, r3; jrp lr }
2: addi r0, r0, -1 /* don't count the trailing NUL */
{ sub r0, r0, r3; jrp lr }
STD_ENDPROC(strncpy_from_user_asm)
.pushsection .fixup,"ax"
strncpy_from_user_fault:
{ movei r0, -EFAULT; jrp lr }
ENDPROC(strncpy_from_user_fault)
.section __ex_table,"a"
.align 4
.word 1b, strncpy_from_user_fault
.popsection
/*
* clear_user_asm takes the user target address in r0 and the
* number of bytes to zero in r1.
* It returns the number of uncopiable bytes (hopefully zero) in r0.
* Note that we don't use a separate .fixup section here since we fall
* through into the "fixup" code as the last straight-line bundle anyway.
*/
STD_ENTRY(clear_user_asm)
{ bz r1, 2f; or r2, r0, r1 }
andi r2, r2, 3
bzt r2, .Lclear_aligned_user_asm
1: { sb r0, zero; addi r0, r0, 1; addi r1, r1, -1 }
bnzt r1, 1b
2: { move r0, r1; jrp lr }
.pushsection __ex_table,"a"
.align 4
.word 1b, 2b
.popsection
.Lclear_aligned_user_asm:
1: { sw r0, zero; addi r0, r0, 4; addi r1, r1, -4 }
bnzt r1, 1b
2: { move r0, r1; jrp lr }
STD_ENDPROC(clear_user_asm)
.pushsection __ex_table,"a"
.align 4
.word 1b, 2b
.popsection
/*
* flush_user_asm takes the user target address in r0 and the
* number of bytes to flush in r1.
* It returns the number of unflushable bytes (hopefully zero) in r0.
*/
STD_ENTRY(flush_user_asm)
bz r1, 2f
{ movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
{ sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
{ and r0, r0, r2; and r1, r1, r2 }
{ sub r1, r1, r0 }
1: { flush r0; addi r1, r1, -CHIP_FLUSH_STRIDE() }
{ addi r0, r0, CHIP_FLUSH_STRIDE(); bnzt r1, 1b }
2: { move r0, r1; jrp lr }
STD_ENDPROC(flush_user_asm)
.pushsection __ex_table,"a"
.align 4
.word 1b, 2b
.popsection
/*
* finv_user_asm takes the user target address in r0 and the
* number of bytes to flush-invalidate in r1.
* It returns the number of not finv'able bytes (hopefully zero) in r0.
*/
STD_ENTRY(finv_user_asm)
bz r1, 2f
{ movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
{ sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
{ and r0, r0, r2; and r1, r1, r2 }
{ sub r1, r1, r0 }
1: { finv r0; addi r1, r1, -CHIP_FINV_STRIDE() }
{ addi r0, r0, CHIP_FINV_STRIDE(); bnzt r1, 1b }
2: { move r0, r1; jrp lr }
STD_ENDPROC(finv_user_asm)
.pushsection __ex_table,"a"
.align 4
.word 1b, 2b
.popsection
