Re: [PATCH 3/5] kexec: Add bit definitions for kimage entry flags

Vivek Goyal
2014-08-25T17:53:47Z

On Fri, Aug 22, 2014 at 06:39:47PM +0000, Geoff Levand wrote:
> Define new kexec preprocessor macros IND_*_BIT that define the bit position of
> the kimage entry flags. Change the existing IND_* flag macros to be defined as
> bit shifts of the corresponding IND_*_BIT macros. Also wrap all C language code
> in kexec.h with #if !defined(__ASSEMBLY__) so assembly files can include kexec.h
> to get the IND_* and IND_*_BIT macros.
>
> Some CPU instruction sets have tests for bit position which are convenient in
> implementing routines that operate on the kimage entry list. The addition of
> these bit position macros in a common location will avoid duplicate definitions
> and the chance that changes to the IND_* flags will not be propagated to
> assembly files.
>
> Signed-off-by: Geoff Levand <geoff@infradead.org>

Looks good to me.

Acked-by: Vivek Goyal <vgoyal@redhat.com>

Vivek

> ---
> include/linux/kexec.h | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index 4b2a0e1..8c628ca 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -1,6 +1,18 @@
> #ifndef LINUX_KEXEC_H
> #define LINUX_KEXEC_H
>
> +#define IND_DESTINATION_BIT 0
> +#define IND_INDIRECTION_BIT 1
> +#define IND_DONE_BIT 2
> +#define IND_SOURCE_BIT 3
> +
> +#define IND_DESTINATION (1 << IND_DESTINATION_BIT)
> +#define IND_INDIRECTION (1 << IND_INDIRECTION_BIT)
> +#define IND_DONE (1 << IND_DONE_BIT)
> +#define IND_SOURCE (1 << IND_SOURCE_BIT)
> +
> +#if !defined(__ASSEMBLY__)
> +
> #include <uapi/linux/kexec.h>
>
> #ifdef CONFIG_KEXEC
> @@ -64,10 +76,6 @@
> */
>
> typedef unsigned long kimage_entry_t;
> -#define IND_DESTINATION 0x1
> -#define IND_INDIRECTION 0x2
> -#define IND_DONE 0x4
> -#define IND_SOURCE 0x8
>
> struct kexec_segment {
> /*
> @@ -312,4 +320,7 @@ struct task_struct;
> static inline void crash_kexec(struct pt_regs *regs) { }
> static inline int kexec_should_crash(struct task_struct *p) { return 0; }
> #endif /* CONFIG_KEXEC */
> +
> +#endif /* !defined(__ASSEBMLY__) */
> +
> #endif /* LINUX_KEXEC_H */
> --
> 1.9.1
>
>
>
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