Re: [PATCH 08/10] jump label v11: x86 support

Konrad Rzeszutek Wilk
2010-09-21T18:30:58Z

On Fri, Sep 17, 2010 at 11:09:22AM -0400, Jason Baron wrote:
> add x86 support for jump label. I'm keeping this patch separate so its clear to
> arch maintainers what was required for x86 support this new feature. hopefully,
> it wouldn't be too painful for other arches.
>
> Signed-off-by: Jason Baron <jbaron@redhat.com>
> ---
> arch/x86/Kconfig | 1 +
> arch/x86/include/asm/jump_label.h | 47 +++++++++++++++++++++++++++++++++++
> arch/x86/kernel/Makefile | 2 +-
> arch/x86/kernel/jump_label.c | 49 +++++++++++++++++++++++++++++++++++++
> arch/x86/kernel/module.c | 3 ++
> 5 files changed, 101 insertions(+), 1 deletions(-)
> create mode 100644 arch/x86/include/asm/jump_label.h
> create mode 100644 arch/x86/kernel/jump_label.c
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 0c14369..a986079 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -60,6 +60,7 @@ config X86
> select ANON_INODES
> select HAVE_ARCH_KMEMCHECK
> select HAVE_USER_RETURN_NOTIFIER
> + select HAVE_ARCH_JUMP_LABEL if !CC_OPTIMIZE_FOR_SIZE
>
> config INSTRUCTION_DECODER
> def_bool (KPROBES || PERF_EVENTS)
> diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h
> new file mode 100644
> index 0000000..b4a2cb4
> --- /dev/null
> +++ b/arch/x86/include/asm/jump_label.h
> @@ -0,0 +1,47 @@
> +#ifndef _ASM_X86_JUMP_LABEL_H
> +#define _ASM_X86_JUMP_LABEL_H
> +
> +#ifdef __KERNEL__
> +
> +#include <linux/types.h>
> +#include <asm/nops.h>
> +
> +#define JUMP_LABEL_NOP_SIZE 5
> +
> +# define JUMP_LABEL_INITIAL_NOP ".byte 0xe9 \n\t .long 0\n\t"
> +
> +# define JUMP_LABEL(key, label) \
> + do { \
> + asm goto("1:" \
> + JUMP_LABEL_INITIAL_NOP \
> + ".pushsection __jump_table, \"a\" \n\t"\
> + _ASM_PTR "1b, %l[" #label "], %c0 \n\t" \
> + ".popsection \n\t" \
> + : : "i" (key) : : label); \
> + } while (0)
> +
> +#endif /* __KERNEL__ */
> +
> +#ifdef CONFIG_X86_64
> +
> +typedef u64 jump_label_t;
> +
> +struct jump_entry {
> + jump_label_t code;
> + jump_label_t target;
> + jump_label_t key;
> +};
> +
> +#else
> +
> +typedef u32 jump_label_t;
> +
> +struct jump_entry {
> + jump_label_t code;
> + jump_label_t target;
> + jump_label_t key;

The format is the same, why not just put the typedef
within the #ifdef?

> +};
> +
> +#endif
> +
> +#endif
> diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
> index 11a9925..dfa1443 100644
> --- a/arch/x86/kernel/Makefile
> +++ b/arch/x86/kernel/Makefile
> @@ -32,7 +32,7 @@ GCOV_PROFILE_paravirt.o := n
> obj-y := process_$(BITS).o signal.o entry_$(BITS).o
> obj-y += traps.o irq.o irq_$(BITS).o dumpstack_$(BITS).o
> obj-y += time.o ioport.o ldt.o dumpstack.o
> -obj-y += setup.o x86_init.o i8259.o irqinit.o
> +obj-y += setup.o x86_init.o i8259.o irqinit.o jump_label.o
> obj-$(CONFIG_X86_VISWS) += visws_quirks.o
> obj-$(CONFIG_X86_32) += probe_roms_32.o
> obj-$(CONFIG_X86_32) += sys_i386_32.o i386_ksyms_32.o
> diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
> new file mode 100644
> index 0000000..b3c0f37
> --- /dev/null
> +++ b/arch/x86/kernel/jump_label.c
> @@ -0,0 +1,49 @@
> +/*
> + * jump label x86 support
> + *
> + * Copyright (C) 2009 Jason Baron <jbaron@redhat.com>

Year.