From: Catalin Marinas <catalin.marinas@arm.com>
To: Steve Capper <steve.capper@arm.com>
Cc: crecklin@redhat.com, ard.biesheuvel@linaro.org, maz@kernel.org,
bhsharma@redhat.com, will@kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH V4 11/11] docs: arm64: Add layout and 52-bit info to memory document
Date: Tue, 6 Aug 2019 16:27:34 +0100 [thread overview]
Message-ID: <20190806152734.GH30716@arrakis.emea.arm.com> (raw)
In-Reply-To: <20190729162117.832-12-steve.capper@arm.com>
On Mon, Jul 29, 2019 at 05:21:17PM +0100, Steve Capper wrote:
> +AArch64 Linux memory layout with 4KB pages + 4 levels (48-bit)::
>
> Start End Size Use
> -----------------------------------------------------------------------
> 0000000000000000 0000ffffffffffff 256TB user
> - ffff000000000000 ffffffffffffffff 256TB kernel
> -
> -
> -AArch64 Linux memory layout with 64KB pages + 2 levels::
> + ffff000000000000 ffff7fffffffffff 128TB kernel logical memory map
> + ffff800000000000 ffff9fffffffffff 32TB kasan shadow region
> + ffffa00000000000 ffffa00007ffffff 128MB bpf jit region
> + ffffa00008000000 ffffa0000fffffff 128MB modules
> + ffffa00010000000 fffffdffbffeffff ~93TB vmalloc
> + fffffdffbfff0000 fffffdfffe5f8fff ~998MB [guard region]
> + fffffdfffe5f9000 fffffdfffe9fffff 4124KB fixed mappings
> + fffffdfffea00000 fffffdfffebfffff 2MB [guard region]
> + fffffdfffec00000 fffffdffffbfffff 16MB PCI I/O space
> + fffffdffffc00000 fffffdffffdfffff 2MB [guard region]
> + fffffdffffe00000 ffffffffffdfffff 2TB vmemmap
> + ffffffffffe00000 ffffffffffffffff 2MB [guard region]
[...]
> +AArch64 Linux memory layout with 64KB pages + 3 levels (52-bit with HW support)::
>
> -For details of the virtual kernel memory layout please see the kernel
> -booting log.
> + Start End Size Use
> + -----------------------------------------------------------------------
> + 0000000000000000 000fffffffffffff 4PB user
> + fff0000000000000 fff7ffffffffffff 2PB kernel logical memory map
> + fff8000000000000 fffd9fffffffffff 1440TB [gap]
> + fffda00000000000 ffff9fffffffffff 512TB kasan shadow region
> + ffffa00000000000 ffffa00007ffffff 128MB bpf jit region
> + ffffa00008000000 ffffa0000fffffff 128MB modules
> + ffffa00010000000 fffff81ffffeffff ~88TB vmalloc
> + fffff81fffff0000 fffffc1ffe58ffff ~3TB [guard region]
> + fffffc1ffe590000 fffffc1ffe9fffff 4544KB fixed mappings
> + fffffc1ffea00000 fffffc1ffebfffff 2MB [guard region]
> + fffffc1ffec00000 fffffc1fffbfffff 16MB PCI I/O space
> + fffffc1fffc00000 fffffc1fffdfffff 2MB [guard region]
> + fffffc1fffe00000 ffffffffffdfffff 3968GB vmemmap
> + ffffffffffe00000 ffffffffffffffff 2MB [guard region]
Since we risk getting these out of sync, I'd rather only maintain two
entries: defconfig (4K pages, 48-bit VA) and the largest (64K pages,
52-bit with HW support).
> +52-bit VA support in the kernel
> +-------------------------------
> +If the ARMv8.2-LVA optional feature is present, and we are running
> +with a 64KB page size; then it is possible to use 52-bits of address
> +space for both userspace and kernel addresses. However, any kernel
> +binary that supports 52-bit must also be able to fall back to 48-bit
> +at early boot time if the hardware feature is not present.
> +
> +This fallback mechanism necessitates the kernel .text to be in the
> +higher addresses s.t. they are invariant to 48/52-bti VAs. Due to
The 's.t.' abbreviation always confused me. Could you please change it
to "so that" in the documentation? (I'm not too bothered about the
commit logs).
Also fix s/bti/bit/.
Otherwise:
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
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next prev parent reply other threads:[~2019-08-06 15:27 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-29 16:21 [PATCH V4 00/11] 52-bit kernel + user VAs Steve Capper
2019-07-29 16:21 ` [PATCH V4 01/11] arm64: mm: Remove bit-masking optimisations for PAGE_OFFSET and VMEMMAP_START Steve Capper
2019-08-05 11:07 ` Catalin Marinas
2019-07-29 16:21 ` [PATCH V4 02/11] arm64: mm: Flip kernel VA space Steve Capper
2019-08-05 11:29 ` Catalin Marinas
2019-08-05 11:50 ` Steve Capper
2019-07-29 16:21 ` [PATCH V4 03/11] arm64: kasan: Switch to using KASAN_SHADOW_OFFSET Steve Capper
2019-08-05 16:37 ` Catalin Marinas
2019-08-06 9:05 ` Steve Capper
2019-07-29 16:21 ` [PATCH V4 04/11] arm64: dump: De-constify VA_START and KASAN_SHADOW_START Steve Capper
2019-08-05 16:38 ` Catalin Marinas
2019-07-29 16:21 ` [PATCH V4 05/11] arm64: mm: Introduce VA_BITS_MIN Steve Capper
2019-08-05 17:17 ` Catalin Marinas
2019-08-05 17:20 ` Catalin Marinas
2019-08-06 9:11 ` Steve Capper
2019-07-29 16:21 ` [PATCH V4 06/11] arm64: mm: Introduce VA_BITS_ACTUAL Steve Capper
2019-08-05 17:26 ` Catalin Marinas
2019-08-06 11:32 ` Steve Capper
2019-08-06 14:48 ` Catalin Marinas
2019-08-07 13:27 ` Steve Capper
2019-07-29 16:21 ` [PATCH V4 07/11] arm64: mm: Logic to make offset_ttbr1 conditional Steve Capper
2019-08-05 17:06 ` Catalin Marinas
2019-07-29 16:21 ` [PATCH V4 08/11] arm64: mm: Separate out vmemmap Steve Capper
2019-08-05 17:07 ` Catalin Marinas
2019-07-29 16:21 ` [PATCH V4 09/11] arm64: mm: Modify calculation of VMEMMAP_SIZE Steve Capper
2019-08-05 17:10 ` Catalin Marinas
2019-07-29 16:21 ` [PATCH V4 10/11] arm64: mm: Introduce 52-bit Kernel VAs Steve Capper
2019-08-05 17:27 ` Catalin Marinas
2019-08-06 14:55 ` Catalin Marinas
2019-08-06 14:58 ` Catalin Marinas
2019-07-29 16:21 ` [PATCH V4 11/11] docs: arm64: Add layout and 52-bit info to memory document Steve Capper
2019-08-06 15:27 ` Catalin Marinas [this message]
2019-08-07 13:29 ` Steve Capper
2019-08-07 14:55 ` Will Deacon
2019-08-07 15:57 ` Steve Capper
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