From: Alex Ghiti <alex@ghiti.fr>
To: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Christoph Hellwig <hch@lst.de>,
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>,
LKML <linux-kernel@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>
Subject: Re: [PATCH v3 11/11] riscv: Make mmap allocation top-down by default
Date: Thu, 18 Apr 2019 02:09:08 -0400 [thread overview]
Message-ID: <23d2a38d-363a-929c-5296-c2f8c3b7d1b4@ghiti.fr> (raw)
In-Reply-To: <CAGXu5jJcQzDQGy907H0WXu-q1sPQaXgjuFbHHW60ajUuksZb3A@mail.gmail.com>
On 4/18/19 1:31 AM, Kees Cook wrote:
> On Wed, Apr 17, 2019 at 12:34 AM Alexandre Ghiti <alex@ghiti.fr> wrote:
>> In order to avoid wasting user address space by using bottom-up mmap
>> allocation scheme, prefer top-down scheme when possible.
>>
>> Before:
>> root@qemuriscv64:~# cat /proc/self/maps
>> 00010000-00016000 r-xp 00000000 fe:00 6389 /bin/cat.coreutils
>> 00016000-00017000 r--p 00005000 fe:00 6389 /bin/cat.coreutils
>> 00017000-00018000 rw-p 00006000 fe:00 6389 /bin/cat.coreutils
>> 00018000-00039000 rw-p 00000000 00:00 0 [heap]
>> 1555556000-155556d000 r-xp 00000000 fe:00 7193 /lib/ld-2.28.so
>> 155556d000-155556e000 r--p 00016000 fe:00 7193 /lib/ld-2.28.so
>> 155556e000-155556f000 rw-p 00017000 fe:00 7193 /lib/ld-2.28.so
>> 155556f000-1555570000 rw-p 00000000 00:00 0
>> 1555570000-1555572000 r-xp 00000000 00:00 0 [vdso]
>> 1555574000-1555576000 rw-p 00000000 00:00 0
>> 1555576000-1555674000 r-xp 00000000 fe:00 7187 /lib/libc-2.28.so
>> 1555674000-1555678000 r--p 000fd000 fe:00 7187 /lib/libc-2.28.so
>> 1555678000-155567a000 rw-p 00101000 fe:00 7187 /lib/libc-2.28.so
>> 155567a000-15556a0000 rw-p 00000000 00:00 0
>> 3fffb90000-3fffbb1000 rw-p 00000000 00:00 0 [stack]
>>
>> After:
>> root@qemuriscv64:~# cat /proc/self/maps
>> 00010000-00016000 r-xp 00000000 fe:00 6389 /bin/cat.coreutils
>> 00016000-00017000 r--p 00005000 fe:00 6389 /bin/cat.coreutils
>> 00017000-00018000 rw-p 00006000 fe:00 6389 /bin/cat.coreutils
>> 00018000-00039000 rw-p 00000000 00:00 0 [heap]
>> 3ff7eb6000-3ff7ed8000 rw-p 00000000 00:00 0
>> 3ff7ed8000-3ff7fd6000 r-xp 00000000 fe:00 7187 /lib/libc-2.28.so
>> 3ff7fd6000-3ff7fda000 r--p 000fd000 fe:00 7187 /lib/libc-2.28.so
>> 3ff7fda000-3ff7fdc000 rw-p 00101000 fe:00 7187 /lib/libc-2.28.so
>> 3ff7fdc000-3ff7fe2000 rw-p 00000000 00:00 0
>> 3ff7fe4000-3ff7fe6000 r-xp 00000000 00:00 0 [vdso]
>> 3ff7fe6000-3ff7ffd000 r-xp 00000000 fe:00 7193 /lib/ld-2.28.so
>> 3ff7ffd000-3ff7ffe000 r--p 00016000 fe:00 7193 /lib/ld-2.28.so
>> 3ff7ffe000-3ff7fff000 rw-p 00017000 fe:00 7193 /lib/ld-2.28.so
>> 3ff7fff000-3ff8000000 rw-p 00000000 00:00 0
>> 3fff888000-3fff8a9000 rw-p 00000000 00:00 0 [stack]
>>
>> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
>> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Kees Cook <keescook@chromium.org>
Thank you very much for all your comments,
Alex
>
> -Kees
>
>> ---
>> arch/riscv/Kconfig | 11 +++++++++++
>> 1 file changed, 11 insertions(+)
>>
>> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
>> index eb56c82d8aa1..f5897e0dbc1c 100644
>> --- a/arch/riscv/Kconfig
>> +++ b/arch/riscv/Kconfig
>> @@ -49,6 +49,17 @@ config RISCV
>> select GENERIC_IRQ_MULTI_HANDLER
>> select ARCH_HAS_PTE_SPECIAL
>> select HAVE_EBPF_JIT if 64BIT
>> + select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
>> + select HAVE_ARCH_MMAP_RND_BITS
>> +
>> +config ARCH_MMAP_RND_BITS_MIN
>> + default 18
>> +
>> +# max bits determined by the following formula:
>> +# VA_BITS - PAGE_SHIFT - 3
>> +config ARCH_MMAP_RND_BITS_MAX
>> + default 33 if 64BIT # SV48 based
>> + default 18
>>
>> config MMU
>> def_bool y
>> --
>> 2.20.1
>>
>
next prev parent reply other threads:[~2019-04-18 6:09 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-17 5:22 [PATCH v3 00/11] Provide generic top-down mmap layout functions Alexandre Ghiti
2019-04-17 5:22 ` [PATCH v3 01/11] mm, fs: Move randomize_stack_top from fs to mm Alexandre Ghiti
2019-04-18 5:20 ` Kees Cook
2019-04-17 5:22 ` [PATCH v3 02/11] arm64: Make use of is_compat_task instead of hardcoding this test Alexandre Ghiti
2019-04-18 4:32 ` Kees Cook
2019-04-18 5:23 ` Alex Ghiti
2019-04-22 19:53 ` Christoph Hellwig
2019-04-17 5:22 ` [PATCH v3 03/11] arm64: Consider stack randomization for mmap base only when necessary Alexandre Ghiti
2019-04-18 4:37 ` Kees Cook
2019-04-18 5:24 ` Alex Ghiti
2019-04-22 19:53 ` Christoph Hellwig
2019-04-17 5:22 ` [PATCH v3 04/11] arm64, mm: Move generic mmap layout functions to mm Alexandre Ghiti
2019-04-18 5:17 ` Kees Cook
2019-04-18 5:55 ` Alex Ghiti
2019-04-18 14:19 ` Kees Cook
2019-04-19 7:20 ` Alex Ghiti
2019-04-22 19:55 ` Christoph Hellwig
2019-04-28 14:27 ` Alex Ghiti
2019-04-22 19:54 ` Christoph Hellwig
2019-04-17 5:22 ` [PATCH v3 05/11] arm: Properly account for stack randomization and stack guard gap Alexandre Ghiti
2019-04-18 5:26 ` Kees Cook
2019-04-18 6:01 ` Alex Ghiti
2019-04-17 5:22 ` [PATCH v3 06/11] arm: Use STACK_TOP when computing mmap base address Alexandre Ghiti
2019-04-18 5:27 ` Kees Cook
2019-04-18 6:04 ` Alex Ghiti
2019-04-17 5:22 ` [PATCH v3 07/11] arm: Use generic mmap top-down layout Alexandre Ghiti
2019-04-18 5:28 ` Kees Cook
2019-04-18 6:06 ` Alex Ghiti
2019-04-17 5:22 ` [PATCH v3 08/11] mips: Properly account for stack randomization and stack guard gap Alexandre Ghiti
2019-04-18 5:30 ` Kees Cook
2019-04-18 6:06 ` Alex Ghiti
2019-04-18 21:27 ` Paul Burton
2019-04-19 7:20 ` Alex Ghiti
2019-04-17 5:22 ` [PATCH v3 09/11] mips: Use STACK_TOP when computing mmap base address Alexandre Ghiti
2019-04-18 5:31 ` Kees Cook
2019-04-18 6:08 ` Alex Ghiti
2019-04-17 5:22 ` [PATCH v3 10/11] mips: Use generic mmap top-down layout Alexandre Ghiti
2019-04-18 5:31 ` Kees Cook
2019-04-18 6:08 ` Alex Ghiti
2019-04-17 5:22 ` [PATCH v3 11/11] riscv: Make mmap allocation top-down by default Alexandre Ghiti
2019-04-18 5:31 ` Kees Cook
2019-04-18 6:09 ` Alex Ghiti [this message]
2019-04-22 19:56 ` Christoph Hellwig
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