7c860db074
This change creates assembler versions of __memcpy_chk/__memset_chk that is implemented in the memcpy/memset assembler code. This change avoids an extra call to memcpy/memset, instead allowing a simple fall through to occur from the chk code into the body of the real implementation. Testing: - Ran the libc_test on __memcpy_chk/__memset_chk on all nexus devices. - Wrote a small test executable that has three calls to __memcpy_chk and three calls to __memset_chk. First call dest_len is length + 1. Second call dest_len is length. Third call dest_len is length - 1. Verified that the first two calls pass, and the third fails. Examined the logcat output on all nexus devices to verify that the fortify error message was sent properly. - I benchmarked the new __memcpy_chk and __memset_chk on all systems. For __memcpy_chk and large copies, the savings is relatively small (about 1%). For small copies, the savings is large on cortex-a15/krait devices (between 5% to 30%). For cortex-a9 and small copies, the speed up is present, but relatively small (about 3% to 5%). For __memset_chk and large copies, the savings is also small (about 1%). However, all processors show larger speed-ups on small copies (about 30% to 100%). Bug: 9293744 Change-Id: I8926d59fe2673e36e8a27629e02a7b7059ebbc98
105 lines
3.2 KiB
ArmAsm
105 lines
3.2 KiB
ArmAsm
/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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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
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <machine/cpu-features.h>
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#include <machine/asm.h>
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#include "libc_events.h"
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/*
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* This code assumes it is running on a processor that supports all arm v7
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* instructions, that supports neon instructions, and that supports
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* unaligned neon instruction accesses to memory.
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*/
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.fpu neon
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ENTRY(__memset_chk)
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cmp r2, r3
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bls done
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ldr r0, error_message
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ldr r1, error_code
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1:
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add r0, pc
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bl __fortify_chk_fail
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error_code:
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.word BIONIC_EVENT_MEMSET_BUFFER_OVERFLOW
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error_message:
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.word error_string-(1b+8)
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END(__memset_chk)
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ENTRY(bzero)
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mov r2, r1
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mov r1, #0
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done:
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// Fall through to memset...
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END(bzero)
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/* memset() returns its first argument. */
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ENTRY(memset)
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.save {r0}
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stmfd sp!, {r0}
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vdup.8 q0, r1
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/* make sure we have at least 32 bytes to write */
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subs r2, r2, #32
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blo 2f
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vmov q1, q0
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1: /* The main loop writes 32 bytes at a time */
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subs r2, r2, #32
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vst1.8 {d0 - d3}, [r0]!
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bhs 1b
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2: /* less than 32 left */
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add r2, r2, #32
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tst r2, #0x10
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beq 3f
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// writes 16 bytes, 128-bits aligned
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vst1.8 {d0, d1}, [r0]!
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3: /* write up to 15-bytes (count in r2) */
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movs ip, r2, lsl #29
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bcc 1f
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vst1.8 {d0}, [r0]!
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1: bge 2f
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vst1.32 {d0[0]}, [r0]!
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2: movs ip, r2, lsl #31
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strmib r1, [r0], #1
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strcsb r1, [r0], #1
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strcsb r1, [r0], #1
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ldmfd sp!, {r0}
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bx lr
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END(memset)
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.data
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error_string:
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.string "memset buffer overflow"
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