0276ebf166
commit e9666d10a5677a494260d60d1fa0b73cc7646eb3 upstream. Currently, CONFIG_JUMP_LABEL just means "I _want_ to use jump label". The jump label is controlled by HAVE_JUMP_LABEL, which is defined like this: #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL) # define HAVE_JUMP_LABEL #endif We can improve this by testing 'asm goto' support in Kconfig, then make JUMP_LABEL depend on CC_HAS_ASM_GOTO. Ugly #ifdef HAVE_JUMP_LABEL will go away, and CONFIG_JUMP_LABEL will match to the real kernel capability. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Tested-by: Sedat Dilek <sedat.dilek@gmail.com> [nc: Fix trivial conflicts in 4.19 arch/xtensa/kernel/jump_label.c doesn't exist yet Ensured CC_HAVE_ASM_GOTO and HAVE_JUMP_LABEL were sufficiently eliminated] Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
101 lines
2.0 KiB
C
101 lines
2.0 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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#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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