Re: [PATCH v2] xen: Remove trigraphs from comments

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Tue, 6 Dec 2022, Michal Orzel wrote:
> MISRA C rule 4.2 states that trigraphs (sequences of two question marks
> followed by a specified third character [=/'()!<>-]) should not be used.
> This applies to both code and comments. Thankfully, we do not use them
> in the code, but still there are some comments where they are
> accidentally used. Fix it.
> 
> With regards to the comments and respective macros in pci_regs.h, these
> were inherited from Linux. Let's knowingly accept the divergence.
> 
> Signed-off-by: Michal Orzel <michal.orzel@xxxxxxx>
> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
> Changes in v2:
>  - use (?!?) for arch-x86_64.h
>  - add a note in commit msg that pci_regs.h originated from Linux and we
>    knowingly accept the divergence
> ---
>  xen/arch/x86/x86_emulate/x86_emulate.h |  2 +-
>  xen/include/public/arch-x86_64.h       |  2 +-
>  xen/include/xen/pci_regs.h             | 12 ++++++------
>  3 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/xen/arch/x86/x86_emulate/x86_emulate.h 
> b/xen/arch/x86/x86_emulate/x86_emulate.h
> index 4732855c40ed..bb7af967ffee 100644
> --- a/xen/arch/x86/x86_emulate/x86_emulate.h
> +++ b/xen/arch/x86/x86_emulate/x86_emulate.h
> @@ -228,7 +228,7 @@ struct x86_emulate_ops
>       * All functions:
>       *  @ctxt:  [IN ] Emulation context info as passed to the emulator.
>       * All memory-access functions:
> -     *  @seg:   [IN ] Segment being dereferenced (specified as x86_seg_??).
> +     *  @seg:   [IN ] Segment being dereferenced (specified as x86_seg_?).
>       *  @offset:[IN ] Offset within segment.
>       *  @p_data:[IN ] Pointer to i/o data buffer (length is @bytes)
>       * Read functions:
> diff --git a/xen/include/public/arch-x86_64.h 
> b/xen/include/public/arch-x86_64.h
> index 5db52de69584..acf705f25e7a 100644
> --- a/xen/include/public/arch-x86_64.h
> +++ b/xen/include/public/arch-x86_64.h
> @@ -22,5 +22,5 @@
>   * A similar callback occurs if the segment selectors are invalid.
>   * failsafe_address is used as the value of eip.
>   *
> - * On x86_64, event_selector and failsafe_selector are ignored (???).
> + * On x86_64, event_selector and failsafe_selector are ignored (?!?).
>   */
> diff --git a/xen/include/xen/pci_regs.h b/xen/include/xen/pci_regs.h
> index ee8e82be36b4..a90aff1712ba 100644
> --- a/xen/include/xen/pci_regs.h
> +++ b/xen/include/xen/pci_regs.h
> @@ -246,13 +246,13 @@
>  #define  PCI_PM_CTRL_STATE_MASK      0x0003  /* Current power state (D0 to 
> D3) */
>  #define  PCI_PM_CTRL_NO_SOFT_RESET   0x0008  /* No reset for D3hot->D0 */
>  #define  PCI_PM_CTRL_PME_ENABLE      0x0100  /* PME pin enable */
> -#define  PCI_PM_CTRL_DATA_SEL_MASK   0x1e00  /* Data select (??) */
> -#define  PCI_PM_CTRL_DATA_SCALE_MASK 0x6000  /* Data scale (??) */
> +#define  PCI_PM_CTRL_DATA_SEL_MASK   0x1e00  /* Data select (?) */
> +#define  PCI_PM_CTRL_DATA_SCALE_MASK 0x6000  /* Data scale (?) */
>  #define  PCI_PM_CTRL_PME_STATUS      0x8000  /* PME pin status */
> -#define PCI_PM_PPB_EXTENSIONS        6       /* PPB support extensions (??) 
> */
> -#define  PCI_PM_PPB_B2_B3    0x40    /* Stop clock when in D3hot (??) */
> -#define  PCI_PM_BPCC_ENABLE  0x80    /* Bus power/clock control enable (??) 
> */
> -#define PCI_PM_DATA_REGISTER 7       /* (??) */
> +#define PCI_PM_PPB_EXTENSIONS        6       /* PPB support extensions (?) */
> +#define  PCI_PM_PPB_B2_B3    0x40    /* Stop clock when in D3hot (?) */
> +#define  PCI_PM_BPCC_ENABLE  0x80    /* Bus power/clock control enable (?) */
> +#define PCI_PM_DATA_REGISTER 7       /* (?) */
>  #define PCI_PM_SIZEOF                8
>  
>  /* AGP registers */
> -- 
> 2.25.1
>