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d19157519c
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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
[hq: Backported to 3.4: Adjust context]
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
50 lines
971 B
C
50 lines
971 B
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (c) 2010 Cavium Networks, Inc.
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*/
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#ifndef _ASM_MIPS_JUMP_LABEL_H
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#define _ASM_MIPS_JUMP_LABEL_H
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#include <linux/types.h>
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#ifdef __KERNEL__
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#define JUMP_LABEL_NOP_SIZE 4
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#ifdef CONFIG_64BIT
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#define WORD_INSN ".dword"
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#else
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#define WORD_INSN ".word"
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#endif
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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:\tnop\n\t"
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"nop\n\t"
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".pushsection __jump_table, \"aw\"\n\t"
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WORD_INSN " 1b, %l[l_yes], %0\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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#endif /* __KERNEL__ */
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#ifdef CONFIG_64BIT
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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_MIPS_JUMP_LABEL_H */
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