Re: [PATCH] parisc: Add MAP_UNINITIALIZED define

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On 10/10/20 11:54 PM, Helge Deller wrote:
> Define MAP_UNINITIALIZED and use same value as other architectures.
> Fixes build of debian foot package.

I'm tempted to #define MAP_UNINITIALIZED to zero.
That flag was invented for embedded usage, and becaue of security reasons
we probably will never deliver uninitialized pages to userspace on parisc.
So, defining it as 0 should be fine, as this fixes build errors and won't
have any other (negative) effect.
Thoughts?

Helge


> Suggested-by: John David Anglin <dave.anglin@xxxxxxxx>
> Signed-off-by: Helge Deller <deller@xxxxxx>
>
> diff --git a/arch/parisc/include/uapi/asm/mman.h b/arch/parisc/include/uapi/asm/mman.h
> index 6fd8871e4081..d828b293b6de 100644
> --- a/arch/parisc/include/uapi/asm/mman.h
> +++ b/arch/parisc/include/uapi/asm/mman.h
> @@ -25,6 +25,8 @@
>  #define MAP_STACK	0x40000		/* give out an address that is best suited for process/thread stacks */
>  #define MAP_HUGETLB	0x80000		/* create a huge page mapping */
>  #define MAP_FIXED_NOREPLACE 0x100000	/* MAP_FIXED which doesn't unmap underlying mapping */
> +#define MAP_UNINITIALIZED 0x4000000	/* For anonymous mmap, memory could be
> +					 * uninitialized */
>
>  #define MS_SYNC		1		/* synchronous memory sync */
>  #define MS_ASYNC	2		/* sync memory asynchronously */
> diff --git a/tools/arch/parisc/include/uapi/asm/mman.h b/tools/arch/parisc/include/uapi/asm/mman.h
> index f9fd1325f5bd..c7af0f2292fc 100644
> --- a/tools/arch/parisc/include/uapi/asm/mman.h
> +++ b/tools/arch/parisc/include/uapi/asm/mman.h
> @@ -39,6 +39,5 @@
>  #define MADV_SOFT_OFFLINE 101
>  /* MAP_32BIT is undefined on parisc, fix it for perf */
>  #define MAP_32BIT	0
> -/* MAP_UNINITIALIZED is undefined on parisc, fix it for perf */
> -#define MAP_UNINITIALIZED	0
> +#define MAP_UNINITIALIZED 0x4000000
>  #endif
>





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