From: Alex Ghiti <alex@ghiti.fr>
To: Christoph Hellwig <hch@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Ralf Baechle <ralf@linux-mips.org>,
Paul Burton <paul.burton@mips.com>,
James Hogan <jhogan@kernel.org>,
Palmer Dabbelt <palmer@sifive.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Luis Chamberlain <mcgrof@kernel.org>,
Kees Cook <keescook@chromium.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org,
linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH 1/4] arm64, mm: Move generic mmap layout functions to mm
Date: Sat, 23 Mar 2019 04:18:02 -0400 [thread overview]
Message-ID: <72751399-3170-059b-b572-b9b9986ca0fd@ghiti.fr> (raw)
In-Reply-To: <20190322132127.GA18602@infradead.org>
On 3/22/19 9:21 AM, Christoph Hellwig wrote:
>> It then introduces a new define ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
>> that can be defined by other architectures to benefit from those functions.
> Can you make this a Kconfig option defined in arch/Kconfig or mm/Kconfig
> and selected by the architectures?
Yes, I will do.
>> -#ifndef STACK_RND_MASK
>> -#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12)) /* 8MB of VA */
>> -#endif
>> -
>> -static unsigned long randomize_stack_top(unsigned long stack_top)
>> -{
>> - unsigned long random_variable = 0;
>> -
>> - if (current->flags & PF_RANDOMIZE) {
>> - random_variable = get_random_long();
>> - random_variable &= STACK_RND_MASK;
>> - random_variable <<= PAGE_SHIFT;
>> - }
>> -#ifdef CONFIG_STACK_GROWSUP
>> - return PAGE_ALIGN(stack_top) + random_variable;
>> -#else
>> - return PAGE_ALIGN(stack_top) - random_variable;
>> -#endif
>> -}
>> -
> Maybe the move of this function can be split into another prep patch,
> as it is only very lightly related?
>
>
Ok, that makes sense.
>> +#if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
>> + defined(ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
> Not sure if it is wrіtten down somehwere or just convention, but I
> general see cpp defined statements aligned with spaces to the
> one on the previous line.
Ok, I will fix that.
> Except for these nitpicks this looks very nice to me, thanks for doing
> this work!
Thanks :)
next prev parent reply other threads:[~2019-03-23 8:18 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-22 7:42 [PATCH 0/4] Provide generic top-down mmap layout functions Alexandre Ghiti
2019-03-22 7:42 ` [PATCH 1/4] arm64, mm: Move generic mmap layout functions to mm Alexandre Ghiti
2019-03-22 13:21 ` Christoph Hellwig
2019-03-23 8:18 ` Alex Ghiti [this message]
2019-03-22 7:42 ` [PATCH 2/4] arm: Use generic mmap top-down layout Alexandre Ghiti
2019-03-22 7:42 ` [PATCH 3/4] mips: " Alexandre Ghiti
2019-03-22 7:42 ` [PATCH 4/4] riscv: Make mmap allocation top-down by default Alexandre Ghiti
2019-03-22 13:22 ` Christoph Hellwig
2019-03-23 8:05 ` Alex Ghiti
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