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bb42ad4e4d
commit 3f0116c323 upstream.
Fengguang Wu, Oleg Nesterov and Peter Zijlstra tracked down
a kernel crash to a GCC bug: GCC miscompiles certain 'asm goto'
constructs, as outlined here:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
Implement a workaround suggested by Jakub Jelinek.
Reported-and-tested-by: Fengguang Wu <fengguang.wu@intel.com>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Suggested-by: Jakub Jelinek <jakub@redhat.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20131015062351.GA4666@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
46 lines
1.0 KiB
C
46 lines
1.0 KiB
C
#ifndef _ASM_POWERPC_JUMP_LABEL_H
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#define _ASM_POWERPC_JUMP_LABEL_H
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/*
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* Copyright 2010 Michael Ellerman, IBM Corp.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/types.h>
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#include <asm/feature-fixups.h>
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#define JUMP_ENTRY_TYPE stringify_in_c(FTR_ENTRY_LONG)
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#define JUMP_LABEL_NOP_SIZE 4
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static __always_inline bool arch_static_branch(struct static_key *key)
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{
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asm_volatile_goto("1:\n\t"
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"nop\n\t"
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".pushsection __jump_table, \"aw\"\n\t"
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JUMP_ENTRY_TYPE "1b, %l[l_yes], %c0\n\t"
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".popsection \n\t"
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: : "i" (key) : : l_yes);
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return false;
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l_yes:
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return true;
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}
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#ifdef CONFIG_PPC64
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typedef u64 jump_label_t;
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#else
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typedef u32 jump_label_t;
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#endif
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struct jump_entry {
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jump_label_t code;
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jump_label_t target;
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jump_label_t key;
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};
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#endif /* _ASM_POWERPC_JUMP_LABEL_H */
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