114 lines
2.4 KiB
C
114 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_JUMP_LABEL_H
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#define _ASM_X86_JUMP_LABEL_H
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#ifndef HAVE_JUMP_LABEL
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/*
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* For better or for worse, if jump labels (the gcc extension) are missing,
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* then the entire static branch patching infrastructure is compiled out.
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* If that happens, the code in here will malfunction. Raise a compiler
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* error instead.
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*
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* In theory, jump labels and the static branch patching infrastructure
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* could be decoupled to fix this.
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*/
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#error asm/jump_label.h included on a non-jump-label kernel
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#endif
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#define JUMP_LABEL_NOP_SIZE 5
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#ifdef CONFIG_X86_64
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# define STATIC_KEY_INIT_NOP P6_NOP5_ATOMIC
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#else
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# define STATIC_KEY_INIT_NOP GENERIC_NOP5_ATOMIC
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#endif
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#include <asm/asm.h>
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#include <asm/nops.h>
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#ifndef __ASSEMBLY__
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#include <linux/stringify.h>
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#include <linux/types.h>
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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:"
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".byte " __stringify(STATIC_KEY_INIT_NOP) "\n\t"
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".pushsection __jump_table, \"aw\" \n\t"
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_ASM_ALIGN "\n\t"
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_ASM_PTR "1b, %l[l_yes], %c0 + %c1 \n\t"
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".popsection \n\t"
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: : "i" (key), "i" (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:"
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".byte 0xe9\n\t .long %l[l_yes] - 2f\n\t"
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"2:\n\t"
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".pushsection __jump_table, \"aw\" \n\t"
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_ASM_ALIGN "\n\t"
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_ASM_PTR "1b, %l[l_yes], %c0 + %c1 \n\t"
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".popsection \n\t"
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: : "i" (key), "i" (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_X86_64
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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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#else /* __ASSEMBLY__ */
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.macro STATIC_JUMP_IF_TRUE target, key, def
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.Lstatic_jump_\@:
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.if \def
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/* Equivalent to "jmp.d32 \target" */
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.byte 0xe9
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.long \target - .Lstatic_jump_after_\@
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.Lstatic_jump_after_\@:
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.else
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.byte STATIC_KEY_INIT_NOP
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.endif
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.pushsection __jump_table, "aw"
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_ASM_ALIGN
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_ASM_PTR .Lstatic_jump_\@, \target, \key
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.popsection
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.endm
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.macro STATIC_JUMP_IF_FALSE target, key, def
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.Lstatic_jump_\@:
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.if \def
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.byte STATIC_KEY_INIT_NOP
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.else
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/* Equivalent to "jmp.d32 \target" */
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.byte 0xe9
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.long \target - .Lstatic_jump_after_\@
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.Lstatic_jump_after_\@:
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.endif
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.pushsection __jump_table, "aw"
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_ASM_ALIGN
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_ASM_PTR .Lstatic_jump_\@, \target, \key + 1
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.popsection
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.endm
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#endif /* __ASSEMBLY__ */
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#endif
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