8df0d57e5c
commit 47c25036b60f27b86ab44b66a8861bcf81cde39b upstream. Insert Branch instruction instead of NOP to make sure assembler don't patch code in forbidden slot. In jump label function, it might be possible to patch Control Transfer Instructions(CTIs) into forbidden slot, which will generate Reserved Instruction exception in MIPS release 6. Signed-off-by: Archer Yan <ayan@wavecomp.com> Reviewed-by: Paul Burton <paul.burton@mips.com> [paul.burton@mips.com: - Add MIPS prefix to subject. - Mark for stable from v4.0, which introduced r6 support, onwards.] Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: stable@vger.kernel.org # v4.0+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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:\tnop\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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"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" (&((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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