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35d43ba8ea
Linux since 4.7 makes interface 'cpu_has_feature' to use jump labels on powerpc if CONFIG_JUMP_LABEL_FEATURE_CHECKS is enabled, in this case however the inline function references GPL-only symbol 'cpu_feature_keys'. ZFS currently uses 'cpu_has_feature' either directly or indirectly from several places; while it is unknown how this issue didn't break ZFS on 64-bit little-endian powerpc, it is known to break ZFS with many Linux versions on both 32-bit and 64-bit big-endian powerpc. Until this issue is fixed in Linux, we have to workaround it by overriding affected inline functions without depending on 'cpu_feature_keys'. Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: WHR <msl0000023508@gmail.com> Closes #14590
121 lines
3.1 KiB
C
121 lines
3.1 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright (C) 2019 Romain Dolbeau
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* <romain.dolbeau@european-processor-initiative.eu>
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*/
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/*
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* USER API:
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*
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* Kernel fpu methods:
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* kfpu_allowed()
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* kfpu_begin()
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* kfpu_end()
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* kfpu_init()
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* kfpu_fini()
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*
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* SIMD support:
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*
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* Following functions should be called to determine whether CPU feature
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* is supported. All functions are usable in kernel and user space.
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* If a SIMD algorithm is using more than one instruction set
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* all relevant feature test functions should be called.
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*
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* Supported features:
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* zfs_altivec_available()
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*/
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#ifndef _LINUX_SIMD_POWERPC_H
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#define _LINUX_SIMD_POWERPC_H
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/* only for __powerpc__ */
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#if defined(__powerpc__)
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#include <linux/preempt.h>
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#include <linux/export.h>
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#include <linux/sched.h>
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#include <asm/switch_to.h>
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#include <sys/types.h>
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#include <linux/version.h>
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#define kfpu_allowed() 1
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#define kfpu_begin() \
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{ \
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preempt_disable(); \
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enable_kernel_altivec(); \
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}
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#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 5, 0)
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#define kfpu_end() \
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{ \
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disable_kernel_altivec(); \
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preempt_enable(); \
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}
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#else
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/* seems that before 4.5 no-one bothered disabling ... */
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#define kfpu_end() preempt_enable()
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#endif
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#define kfpu_init() 0
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#define kfpu_fini() ((void) 0)
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/*
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* Linux 4.7 makes cpu_has_feature to use jump labels on powerpc if
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* CONFIG_JUMP_LABEL_FEATURE_CHECKS is enabled, in this case however it
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* references GPL-only symbol cpu_feature_keys. Therefore we overrides this
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* interface when it is detected being GPL-only.
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*/
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#if defined(CONFIG_JUMP_LABEL_FEATURE_CHECKS) && \
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defined(HAVE_CPU_HAS_FEATURE_GPL_ONLY)
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#define cpu_has_feature(feature) early_cpu_has_feature(feature)
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#endif
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/*
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* Check if AltiVec instruction set is available
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*/
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static inline boolean_t
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zfs_altivec_available(void)
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{
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boolean_t res;
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/* suggested by macallan at netbsd dot org */
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#if defined(__powerpc64__)
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u64 msr;
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#else
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u32 msr;
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#endif
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kfpu_begin();
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__asm volatile("mfmsr %0" : "=r"(msr));
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/*
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* 64 bits -> need to check bit 38
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* Power ISA Version 3.0B
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* p944
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* 32 bits -> Need to check bit 6
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* AltiVec Technology Programming Environments Manual
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* p49 (2-9)
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* They are the same, as ppc counts 'backward' ...
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*/
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res = (msr & 0x2000000) != 0;
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kfpu_end();
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return (res);
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}
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#endif /* defined(__powerpc) */
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#endif /* _LINUX_SIMD_POWERPC_H */
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