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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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d5caa4dbf9
Use a brcl 0,2 instruction for jump label nops during compile time, so we don't mix up the different nops during mcount/hotpatch call site detection. The initial jump label code instruction replacement will exchange these instructions with either a branch or a brcl 0,0 instruction. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
43 lines
889 B
C
43 lines
889 B
C
#ifndef _ASM_S390_JUMP_LABEL_H
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#define _ASM_S390_JUMP_LABEL_H
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#include <linux/types.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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#ifdef CONFIG_64BIT
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#define ASM_PTR ".quad"
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#define ASM_ALIGN ".balign 8"
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#else
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#define ASM_PTR ".long"
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#define ASM_ALIGN ".balign 4"
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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)
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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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ASM_ALIGN "\n"
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ASM_PTR " 0b, %l[label], %0\n"
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".popsection\n"
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: : "X" (key) : : 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
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