feat: 基于汇编实现内核对用户态内存清零的功能
背景：LOS_UserMemClear接口原有实现是通过在内核中 申请一块堆内存并对其清零，调用copy_to_user来达到 对用户态内存清零的目的，需要使用堆内存。 修改方案：基于汇编实现内核对用户态内存清零的功能。 close #I3XXT0 Change-Id: I27cb1e45559cb75a9b330799fe427abd54f51c15 Signed-off-by: Haryslee <lihao189@huawei.com>
This commit is contained in:
Haryslee
parent
b8e18ffdf1
commit
9db3407589
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/*
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* Copyright (c) 2021-2021 Huawei Device Co., Ltd. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this list of
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* conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice, this list
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* of conditions and the following disclaimer in the documentation and/or other materials
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* provided with the distribution.
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*
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* 3. Neither the name of the copyright holder nor the names of its contributors may be used
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* to endorse or promote products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _ARM_USER_CLEAR_H
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#define _ARM_USER_CLEAR_H
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#include "los_typedef.h"
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#ifdef __cplusplus
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#if __cplusplus
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extern "C" {
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#endif /* __cplusplus */
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#endif /* __cplusplus */
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size_t _arm_clear_user(void *addr, size_t bytes);
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#ifdef __cplusplus
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#if __cplusplus
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}
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#endif /* __cplusplus */
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#endif /* __cplusplus */
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#endif /* _ARM_USER_CLEAR_H */
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@ -0,0 +1,100 @@
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/*
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* Copyright (c) 2021-2021 Huawei Device Co., Ltd. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this list of
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* conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice, this list
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* of conditions and the following disclaimer in the documentation and/or other materials
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* provided with the distribution.
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*
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* 3. Neither the name of the copyright holder nor the names of its contributors may be used
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* to endorse or promote products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "asm.h"
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.syntax unified
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.arm
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// size_t _arm_clear_user(void *addr, size_t bytes)
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FUNCTION(_arm_clear_user)
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push {r0-r6, lr}
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cmp r1, #0
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beq .Lclear_user_return
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tst r0, #7
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beq .Lclear_user_aligned
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.Lclear_user_byte:
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mov r2, #0
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0: strb r2, [r0], #1
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subs r1, r1, #1
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beq .Lclear_user_return
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tst r0, #7
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bne 0b
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.Lclear_user_aligned:
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eor r3, r3
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eor r4, r4
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bics r2, r1, #15
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bne .Lclear_user_16bytes
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bics r2, r1, #7
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bne .Lclear_user_8bytes
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b .Lclear_user_remaining
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.Lclear_user_16bytes:
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eor r5, r5
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eor r6, r6
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1: stmia r0!, {r3, r4, r5, r6}
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subs r2, r2, #16
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bne 1b
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ands r1, r1, #15
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beq .Lclear_user_return
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bics r2, r1, #7
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beq .Lclear_user_remaining
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.Lclear_user_8bytes:
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2: stmia r0!, {r3, r4}
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ands r1, r1, #7
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beq .Lclear_user_return
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.Lclear_user_remaining:
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mov r2, #0
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3: strb r2, [r0], #1
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subs r1, r1, #1
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bne 3b
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.Lclear_user_return:
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pop {r0-r6, lr}
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mov r0, #0
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bx lr
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.Lclear_user_err:
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pop {r0, r1}
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sub r0, r2, r0
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sub r0, r1, r0
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pop {r2-r6, lr}
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bx lr
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.pushsection __exc_table, "a"
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.long 0b, .Lclear_user_err
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.long 1b, .Lclear_user_err
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.long 2b, .Lclear_user_err
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.long 3b, .Lclear_user_err
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.popsection
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@ -31,6 +31,7 @@
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#include "user_copy.h"
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#include "arm_user_copy.h"
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#include "arm_user_clear.h"
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#include "securec.h"
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#include "los_memory.h"
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#include "los_vm_map.h"
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@ -96,15 +97,9 @@ INT32 LOS_UserMemClear(unsigned char *buf, UINT32 len)
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if (!LOS_IsUserAddressRange((vaddr_t)(UINTPTR)buf, len)) {
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(VOID)memset_s(buf, len, 0, len);
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} else {
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unsigned char *tmp = (unsigned char *)LOS_MemAlloc(OS_SYS_MEM_ADDR, len);
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if (tmp == NULL) {
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return -ENOMEM;
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if (_arm_clear_user(buf, len)) {
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return -EFAULT;
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}
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(VOID)memset_s(tmp, len, 0, len);
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if (_arm_user_copy(buf, tmp, len) != 0) {
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ret = -EFAULT;
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}
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LOS_MemFree(OS_SYS_MEM_ADDR, tmp);
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}
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return ret;
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}
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@ -416,42 +416,20 @@ INT32 OsGetKernelVaddr(const LosVmSpace *space, VADDR_T vaddr, VADDR_T *kvaddr)
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STATIC INT32 OsSetBss(const LD_ELF_PHDR *elfPhdr, INT32 fd, UINTPTR bssStart, UINT32 bssEnd, UINT32 elfProt)
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{
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UINTPTR bssPageStart, bssStartPageAlign, bssEndPageAlign;
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UINTPTR bssStartPageAlign, bssEndPageAlign;
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UINTPTR mapBase;
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UINT32 offset, size;
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UINT32 bssMapSize;
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INT32 stackFlags;
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INT32 ret;
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vaddr_t kvaddr = 0;
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bssPageStart = ROUNDDOWN(bssStart, PAGE_SIZE);
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bssStartPageAlign = ROUNDUP(bssStart, PAGE_SIZE);
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bssEndPageAlign = ROUNDUP(bssEnd, PAGE_SIZE);
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ret = LOS_UnMMap(bssPageStart, (bssEndPageAlign - bssPageStart));
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if ((ret != LOS_OK) && (bssPageStart != 0)) {
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PRINT_ERR("%s[%d], Failed to unmap a region, vaddr: %#x!\n", __FUNCTION__, __LINE__, bssPageStart);
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}
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ret = LOS_UserSpaceVmAlloc(OsCurrProcessGet()->vmSpace, PAGE_SIZE, (VOID **)&bssPageStart,
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0, OsCvtProtFlagsToRegionFlags(elfProt, MAP_FIXED));
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if (ret != LOS_OK) {
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PRINT_ERR("%s[%d], Failed to do vmm alloc!\n", __FUNCTION__, __LINE__);
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return -ENOMEM;
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}
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ret = OsGetKernelVaddr(OsCurrProcessGet()->vmSpace, bssPageStart, &kvaddr);
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if (ret != LOS_OK) {
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PRINT_ERR("%s[%d]\n", __FUNCTION__, __LINE__);
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ret = LOS_UserMemClear((VOID *)bssStart, PAGE_SIZE - ROUNDOFFSET(bssStart, PAGE_SIZE));
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if (ret != 0) {
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PRINT_ERR("%s[%d], Failed to clear bss\n", __FUNCTION__, __LINE__);
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return -EFAULT;
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}
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(VOID)memset_s((VOID *)(UINTPTR)kvaddr, PAGE_SIZE, 0, PAGE_SIZE);
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offset = ROUNDDOWN(elfPhdr->offset + elfPhdr->fileSize, PAGE_SIZE);
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size = ROUNDOFFSET(elfPhdr->offset + elfPhdr->fileSize, PAGE_SIZE);
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ret = OsReadELFInfo(fd, (UINT8 *)(UINTPTR)kvaddr, size, offset);
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if (ret != LOS_OK) {
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PRINT_ERR("%s[%d]\n", __FUNCTION__, __LINE__);
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return -EIO;
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}
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bssMapSize = bssEndPageAlign - bssStartPageAlign;
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if (bssMapSize > 0) {
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