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Date: Tue, 9 Jan 2024 20:36:47 +0000
From: Matthew Wilcox <willy@infradead.org>
To: jeffxu@chromium.org
Cc: akpm@linux-foundation.org, keescook@chromium.org, jannh@google.com,
	sroettger@google.com, gregkh@linuxfoundation.org,
	torvalds@linux-foundation.org, usama.anjum@collabora.com,
	jeffxu@google.com, jorgelo@chromium.org, groeck@chromium.org,
	linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	linux-mm@kvack.org, pedro.falcato@gmail.com, dave.hansen@intel.com,
	linux-hardening@vger.kernel.org, deraadt@openbsd.org
Subject: Re: [RFC PATCH v5 2/4] mseal: add mseal syscall
Message-ID: <ZZ2uXyPCE+l2Uccr@casper.infradead.org>
References: <20240109154547.1839886-1-jeffxu@chromium.org>
 <20240109154547.1839886-3-jeffxu@chromium.org>
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In-Reply-To: <20240109154547.1839886-3-jeffxu@chromium.org>

On Tue, Jan 09, 2024 at 03:45:40PM +0000, jeffxu@chromium.org wrote:
> +extern bool can_modify_mm(struct mm_struct *mm, unsigned long start,
> +		unsigned long end);
> +extern bool can_modify_mm_madv(struct mm_struct *mm, unsigned long start,
> +		unsigned long end, int behavior);

unnecessary use of extern.

> +static inline unsigned long get_mmap_seals(unsigned long prot,
> +	unsigned long flags)

needs more than one tab indent so it doesn't look like part of the body.

> +{
> +	unsigned long vm_seals;
> +
> +	if (prot & PROT_SEAL)
> +		vm_seals = VM_SEALED | VM_SEALABLE;
> +	else
> +		vm_seals = (flags & MAP_SEALABLE) ? VM_SEALABLE:0;

need spaces around the :

> +++ b/include/uapi/asm-generic/mman-common.h
> @@ -17,6 +17,11 @@
>  #define PROT_GROWSDOWN	0x01000000	/* mprotect flag: extend change to start of growsdown vma */
>  #define PROT_GROWSUP	0x02000000	/* mprotect flag: extend change to end of growsup vma */
>  
> +/*
> + * The PROT_SEAL defines memory sealing in the prot argument of mmap().
> + */
> +#define PROT_SEAL	_BITUL(26)	/* 0x04000000 */

why not follow the existing style?

> +static inline void set_vma_sealed(struct vm_area_struct *vma)
> +{
> +	vma->__vm_flags |= VM_SEALED;
> +}

uhh ... vm_flags_set() ?