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Date:   Mon, 16 Oct 2023 17:05:07 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     jeffxu@chromium.org
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Subject: Re: [RFC PATCH v1 1/8] Add mseal syscall
Message-ID: <2023101614-scarce-discount-d7ff@gregkh>
References: <20231016143828.647848-1-jeffxu@chromium.org>
 <20231016143828.647848-2-jeffxu@chromium.org>
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On Mon, Oct 16, 2023 at 02:38:20PM +0000, jeffxu@chromium.org wrote:
> +#ifdef CONFIG_MSEAL
> +	/*
> +	 * bit masks for seal.
> +	 * need this since vm_flags is full.
> +	 */
> +	unsigned long vm_seals;		/* seal flags, see mm.h. */

"unsigned long" and yet:

> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index c0cb22cd607d..f574c7dbee76 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -802,6 +802,8 @@ asmlinkage long sys_process_mrelease(int pidfd, unsigned int flags);
>  asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size,
>  			unsigned long prot, unsigned long pgoff,
>  			unsigned long flags);
> +asmlinkage long sys_mseal(unsigned long start, size_t len, unsigned int types,
> +			  unsigned int flags);

"unsigned int"?

Why the mis-match?

> --- a/include/uapi/linux/mman.h
> +++ b/include/uapi/linux/mman.h
> @@ -55,4 +55,10 @@ struct cachestat {
>  	__u64 nr_recently_evicted;
>  };
>  
> +#define MM_SEAL_MSEAL		0x1
> +#define MM_SEAL_MPROTECT	0x2
> +#define MM_SEAL_MUNMAP		0x4
> +#define MM_SEAL_MMAP		0x8
> +#define MM_SEAL_MREMAP		0x10

I think we can use the BIT() macro in uapi .h files now, it is _BITUL().
Might want to use it here too to make it obvious what is happening.

thanks,

greg k-h