61 lines
1.4 KiB
C
61 lines
1.4 KiB
C
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/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_S390_JUMP_LABEL_H
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#define _ASM_S390_JUMP_LABEL_H
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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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#include <linux/stringify.h>
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#define JUMP_LABEL_NOP_SIZE 6
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#define JUMP_LABEL_NOP_OFFSET 2
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#if __GNUC__ < 9
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#define JUMP_LABEL_STATIC_KEY_CONSTRAINT "X"
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#else
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#define JUMP_LABEL_STATIC_KEY_CONSTRAINT "jdd"
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#endif
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/*
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* We use a brcl 0,2 instruction for jump labels at compile time so it
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* can be easily distinguished from a hotpatch generated instruction.
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*/
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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("0: brcl 0,"__stringify(JUMP_LABEL_NOP_OFFSET)"\n"
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".pushsection __jump_table, \"aw\"\n"
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".balign 8\n"
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".quad 0b, %l[label], %0+%1\n"
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".popsection\n"
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: : JUMP_LABEL_STATIC_KEY_CONSTRAINT (key), "i" (branch) : : label);
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return false;
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label:
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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("0: brcl 15, %l[label]\n"
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".pushsection __jump_table, \"aw\"\n"
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".balign 8\n"
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".quad 0b, %l[label], %0+%1\n"
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".popsection\n"
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: : JUMP_LABEL_STATIC_KEY_CONSTRAINT (key), "i" (branch) : : label);
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return false;
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label:
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return true;
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}
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typedef unsigned long 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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