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c838b580ca
Both arch_static_branch() & arch_static_branch_jump() emit a control transfer instruction (ie. branch or jump) without disabling assembler re-ordering. As such the assembler will automatically fill their delay slots. Both functions follow their branch or jump with an explicit nop that at first appears to be there to fill the delay slot, but given that the assembler will do that the explicit nops serve no purpose & we end up with our branch or jump followed by 2 nops. Remove the redundant nops. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org
70 lines
1.4 KiB
C
70 lines
1.4 KiB
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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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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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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#ifdef CONFIG_CPU_MICROMIPS
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#define B_INSN "b32"
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#else
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#define B_INSN "b"
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#endif
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static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
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{
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asm_volatile_goto("1:\t" B_INSN " 2f\n\t"
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"2:\t.insn\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" (&((char *)key)[branch]) : : 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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static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch)
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{
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asm_volatile_goto("1:\tj %l[l_yes]\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" (&((char *)key)[branch]) : : 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_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 /* __ASSEMBLY__ */
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#endif /* _ASM_MIPS_JUMP_LABEL_H */
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