Re: [RFC PATCH 01/25] Documentation: kvx: Add basic documentation

Jeff Xie
2023-01-18T15:11:08Z

On Wed, Jan 4, 2023 at 1:04 AM Yann Sionneau <ysionneau@kalray.eu> wrote:
>
> Add some documentation for kvx arch and its Linux port.
>
> CC: Jonathan Corbet <corbet@lwn.net>
> CC: linux-doc@vger.kernel.org
> CC: linux-kernel@vger.kernel.org
> Co-developed-by: Clement Leger <clement.leger@bootlin.com>
> Signed-off-by: Clement Leger <clement.leger@bootlin.com>
> Co-developed-by: Guillaume Thouvenin <gthouvenin@kalray.eu>
> Signed-off-by: Guillaume Thouvenin <gthouvenin@kalray.eu>
> Signed-off-by: Yann Sionneau <ysionneau@kalray.eu>
> ---
> Documentation/kvx/kvx-exceptions.txt | 246 ++++++++++++++++++++++++
> Documentation/kvx/kvx-iommu.txt | 183 ++++++++++++++++++
> Documentation/kvx/kvx-mmu.txt | 272 +++++++++++++++++++++++++++
> Documentation/kvx/kvx-smp.txt | 36 ++++
> Documentation/kvx/kvx.txt | 268 ++++++++++++++++++++++++++
> 5 files changed, 1005 insertions(+)
> create mode 100644 Documentation/kvx/kvx-exceptions.txt
> create mode 100644 Documentation/kvx/kvx-iommu.txt
> create mode 100644 Documentation/kvx/kvx-mmu.txt
> create mode 100644 Documentation/kvx/kvx-smp.txt
> create mode 100644 Documentation/kvx/kvx.txt

[...]

> +Virtual and physical memory
> +===========================
> +
> +The mapping used and the memory management is described in
> +Documentation/kvx/kvx-mmu.txt.
> +Our Kernel is compiled using virtual addresses that starts at
> +0xffffff0000000000. But when it is started the kernel uses physical addresses.
> +Before calling the first function arch_low_level_start() we configure 2 entries
> +of the LTLB.
> +
> +The first entry will map the first 1G of virtual address space to the first
> +1G of DDR:
> + - TLB[0]: 0xffffff0000000000 -> 0x100000000 (size 512Mo)

Maybe should change it to:
- TLB[0]: 0xffffff8000000000 -> 0x100000000 (size 512Mo)

As the PAGE_OFFSET = 0xffffff8000000000

[...]

--
Thanks,
JeffXie