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    Subject[patch 01/16] x86/entry: Provide IDTENTRY_IST
    Same as IDTENTRY but for exceptions which run on Interrupt STacks (IST) on
    64bit. For 32bit this maps to IDTENTRY.

    There are 3 variants which will be used:
    IDTENTRY_MCE
    IDTENTRY_DB
    IDTENTRY_NMI

    These map to IDTENTRY_IST, but only the MCE and DB variants are emitting
    ASM code as the NMI entry needs hand crafted ASM still.

    The function defines do not contain any idtenter/exit calls as these
    exceptions need special treatment.

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    ---
    arch/x86/include/asm/idtentry.h | 70 ++++++++++++++++++++++++++++++++++++++++
    1 file changed, 70 insertions(+)

    --- a/arch/x86/include/asm/idtentry.h
    +++ b/arch/x86/include/asm/idtentry.h
    @@ -111,6 +111,58 @@ NOKPROBE_SYMBOL(func); \
    static __always_inline void __##func(struct pt_regs *regs, \
    unsigned long error_code)

    +#ifdef CONFIG_X86_64
    +/**
    + * DECLARE_IDTENTRY_IST - Declare functions for IST handling IDT entry points
    + * @vector: Vector number (ignored for C)
    + * @func: Function name of the entry point
    + *
    + * Declares three functions:
    + * - The ASM entry point: asm_##func
    + * - The XEN PV trap entry point: xen_##func (maybe unused)
    + * - The C handler called from the ASM entry point
    + */
    +#define DECLARE_IDTENTRY_IST(vector, func) \
    + asmlinkage void asm_##func(void); \
    + asmlinkage void xen_asm_##func(void); \
    + __visible void func(struct pt_regs *regs)
    +
    +/**
    + * DEFINE_IDTENTRY_IST - Emit code for IST entry points
    + * @func: Function name of the entry point
    + *
    + * This provides two entry points:
    + * - The real IST based entry
    + * - The regular stack based entry invoked when coming from user mode
    + * or XEN_PV
    + */
    +#define DEFINE_IDTENTRY_IST(func) \
    +static __always_inline void __##func(struct pt_regs *regs); \
    + \
    +__visible notrace void func(struct pt_regs *regs) \
    +{ \
    + __##func (regs); \
    +} \
    +NOKPROBE_SYMBOL(func); \
    + \
    +static __always_inline void __##func(struct pt_regs *regs)
    +
    +#else /* CONFIG_X86_64 */
    +/* Maps to a regular IDTENTRY on 32bit for now */
    +# define DECLARE_IDTENTRY_IST DECLARE_IDTENTRY
    +# define DEFINE_IDTENTRY_IST DEFINE_IDTENTRY
    +#endif /* !CONFIG_X86_64 */
    +
    +/* C-Code mapping */
    +#define DECLARE_IDTENTRY_MCE DECLARE_IDTENTRY_IST
    +#define DEFINE_IDTENTRY_MCE DEFINE_IDTENTRY_IST
    +
    +#define DECLARE_IDTENTRY_NMI DECLARE_IDTENTRY_IST
    +#define DEFINE_IDTENTRY_NMI DEFINE_IDTENTRY_IST
    +
    +#define DECLARE_IDTENTRY_DEBUG DECLARE_IDTENTRY_IST
    +#define DEFINE_IDTENTRY_DEBUG DEFINE_IDTENTRY_IST
    +
    #else /* !__ASSEMBLY__ */

    /* Defines for ASM code to construct the IDT entries */
    @@ -123,6 +175,24 @@ static __always_inline void __##func(str
    /* Special case for 32bit IRET 'trap'. Do not emit ASM code */
    #define DECLARE_IDTENTRY_SW(vector, func)

    +#ifdef CONFIG_X86_64
    +# define DECLARE_IDTENTRY_MCE(vector, func) \
    + idtentry_mce_db vector asm_##func func
    +
    +# define DECLARE_IDTENTRY_DEBUG(vector, func) \
    + idtentry_mce_db vector asm_##func func
    +
    +#else
    +# define DECLARE_IDTENTRY_MCE(vector, func) \
    + DECLARE_IDTENTRY(vector, func)
    +
    +# define DECLARE_IDTENTRY_DEBUG(vector, func) \
    + DECLARE_IDTENTRY(vector, func)
    +#endif
    +
    +/* No ASM code emitted for NMI */
    +# define DECLARE_IDTENTRY_NMI(vector, func)
    +
    #endif /* __ASSEMBLY__ */

    /* Simple exception entries: */
    \
     
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      Last update: 2020-02-26 00:29    [W:3.715 / U:0.580 seconds]
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