![Matt Brown](/assets/img/avatar_default.png)
The xor_vmx.c file is used for the RAID5 xor operations. In these functions altivec is enabled to run the operation and then disabled. The code uses enable_kernel_altivec() around the core of the algorithm, however the whole file is built with -maltivec, so the compiler is within its rights to generate altivec code anywhere. This has been seen at least once in the wild: 0:mon> di $xor_altivec_2 c0000000000b97d0 3c4c01d9 addis r2,r12,473 c0000000000b97d4 3842db30 addi r2,r2,-9424 c0000000000b97d8 7c0802a6 mflr r0 c0000000000b97dc f8010010 std r0,16(r1) c0000000000b97e0 60000000 nop c0000000000b97e4 7c0802a6 mflr r0 c0000000000b97e8 faa1ffa8 std r21,-88(r1) ... c0000000000b981c f821ff41 stdu r1,-192(r1) c0000000000b9820 7f8101ce stvx v28,r1,r0 <-- POP c0000000000b9824 38000030 li r0,48 c0000000000b9828 7fa101ce stvx v29,r1,r0 ... c0000000000b984c 4bf6a06d bl c0000000000238b8 # enable_kernel_altivec This patch splits the non-altivec code into xor_vmx_glue.c which calls the altivec functions in xor_vmx.c. By compiling xor_vmx_glue.c without -maltivec we can guarantee that altivec instruction will not be executed outside of the enable/disable block. Signed-off-by: Matt Brown <matthew.brown.dev@gmail.com> [mpe: Rework change log and include disassembly] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
161 lines
3.2 KiB
C
161 lines
3.2 KiB
C
/*
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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 as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Copyright (C) IBM Corporation, 2012
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*
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* Author: Anton Blanchard <anton@au.ibm.com>
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*/
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/*
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* Sparse (as at v0.5.0) gets very, very confused by this file.
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* Make it a bit simpler for it.
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*/
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#if !defined(__CHECKER__)
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#include <altivec.h>
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#else
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#define vec_xor(a, b) a ^ b
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#define vector __attribute__((vector_size(16)))
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#endif
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#include "xor_vmx.h"
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typedef vector signed char unative_t;
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#define DEFINE(V) \
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unative_t *V = (unative_t *)V##_in; \
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unative_t V##_0, V##_1, V##_2, V##_3
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#define LOAD(V) \
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do { \
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V##_0 = V[0]; \
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V##_1 = V[1]; \
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V##_2 = V[2]; \
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V##_3 = V[3]; \
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} while (0)
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#define STORE(V) \
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do { \
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V[0] = V##_0; \
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V[1] = V##_1; \
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V[2] = V##_2; \
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V[3] = V##_3; \
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} while (0)
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#define XOR(V1, V2) \
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do { \
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V1##_0 = vec_xor(V1##_0, V2##_0); \
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V1##_1 = vec_xor(V1##_1, V2##_1); \
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V1##_2 = vec_xor(V1##_2, V2##_2); \
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V1##_3 = vec_xor(V1##_3, V2##_3); \
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} while (0)
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void __xor_altivec_2(unsigned long bytes, unsigned long *v1_in,
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unsigned long *v2_in)
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{
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DEFINE(v1);
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DEFINE(v2);
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unsigned long lines = bytes / (sizeof(unative_t)) / 4;
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do {
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LOAD(v1);
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LOAD(v2);
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XOR(v1, v2);
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STORE(v1);
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v1 += 4;
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v2 += 4;
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} while (--lines > 0);
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}
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void __xor_altivec_3(unsigned long bytes, unsigned long *v1_in,
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unsigned long *v2_in, unsigned long *v3_in)
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{
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DEFINE(v1);
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DEFINE(v2);
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DEFINE(v3);
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unsigned long lines = bytes / (sizeof(unative_t)) / 4;
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do {
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LOAD(v1);
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LOAD(v2);
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LOAD(v3);
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XOR(v1, v2);
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XOR(v1, v3);
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STORE(v1);
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v1 += 4;
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v2 += 4;
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v3 += 4;
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} while (--lines > 0);
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}
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void __xor_altivec_4(unsigned long bytes, unsigned long *v1_in,
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unsigned long *v2_in, unsigned long *v3_in,
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unsigned long *v4_in)
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{
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DEFINE(v1);
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DEFINE(v2);
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DEFINE(v3);
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DEFINE(v4);
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unsigned long lines = bytes / (sizeof(unative_t)) / 4;
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do {
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LOAD(v1);
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LOAD(v2);
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LOAD(v3);
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LOAD(v4);
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XOR(v1, v2);
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XOR(v3, v4);
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XOR(v1, v3);
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STORE(v1);
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v1 += 4;
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v2 += 4;
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v3 += 4;
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v4 += 4;
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} while (--lines > 0);
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}
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void __xor_altivec_5(unsigned long bytes, unsigned long *v1_in,
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unsigned long *v2_in, unsigned long *v3_in,
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unsigned long *v4_in, unsigned long *v5_in)
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{
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DEFINE(v1);
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DEFINE(v2);
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DEFINE(v3);
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DEFINE(v4);
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DEFINE(v5);
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unsigned long lines = bytes / (sizeof(unative_t)) / 4;
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do {
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LOAD(v1);
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LOAD(v2);
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LOAD(v3);
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LOAD(v4);
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LOAD(v5);
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XOR(v1, v2);
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XOR(v3, v4);
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XOR(v1, v5);
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XOR(v1, v3);
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STORE(v1);
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v1 += 4;
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v2 += 4;
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v3 += 4;
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v4 += 4;
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v5 += 4;
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} while (--lines > 0);
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}
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