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65 lines
1.6 KiB
65 lines
1.6 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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/* Copyright (C) 2018 Cadence Design Systems Inc. */ |
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#ifndef _ASM_XTENSA_JUMP_LABEL_H |
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#define _ASM_XTENSA_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 3 |
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static __always_inline bool arch_static_branch(struct static_key *key, |
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bool branch) |
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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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".word 1b, %l[l_yes], %c0\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, |
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bool branch) |
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{ |
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/* |
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* Xtensa assembler will mark certain points in the code |
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* as unreachable, so that later assembler or linker relaxation |
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* passes could use them. A spot right after the J instruction |
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* is one such point. Assembler and/or linker may insert padding |
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* or literals here, breaking code flow in case the J instruction |
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* is later replaced with NOP. Put a label right after the J to |
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* make it reachable and wrap both into a no-transform block |
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* to avoid any assembler interference with this. |
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*/ |
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asm_volatile_goto("1:\n\t" |
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".begin no-transform\n\t" |
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"_j %l[l_yes]\n\t" |
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"2:\n\t" |
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".end no-transform\n\t" |
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".pushsection __jump_table, \"aw\"\n\t" |
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".word 1b, %l[l_yes], %c0\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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typedef u32 jump_label_t; |
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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
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