From: Christoph Hellwig <hch@infradead.org>
To: Mike Rapoport <rppt@linux.ibm.com>
Cc: Anup Patel <Anup.Patel@wdc.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Palmer Dabbelt <palmer@sifive.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>,
Atish Patra <Atish.Patra@wdc.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
"linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>
Subject: Re: [PATCH v2 3/5] RISC-V: Allow booting kernel from any 4KB aligned address
Date: Sat, 23 Mar 2019 10:24:21 -0700 [thread overview]
Message-ID: <20190323172421.GA14080@infradead.org> (raw)
In-Reply-To: <20190323154012.GA25149@rapoport-lnx>
On Sat, Mar 23, 2019 at 05:40:12PM +0200, Mike Rapoport wrote:
> I have no general objection, but I presume the patch will be significantly
> simplified if the addition of 4K pages support will follow the removal of
> the trampoline_pd_dir.
>
> That said, I didn't look into the details, since they will change
> substantially, only some comments on the Kconfig part.
>
> On the high level, have you considered using large pages in setup_vm() and
> the remapping everything with 4K pages in setup_vm_final()? This might
> save you the whole ops-> churn.
That would be a great start. That being said the current tiny memory
RISC-V devices don't even have a MMU, so the kernel pagetable mapping
isn't even relevant for them. I'm just not sure adding more complexity
in the early boot path for a borderline case (MMU and tiny memory
with a tiny kernel image) is reall worth all the complexity.
next prev parent reply other threads:[~2019-03-23 17:24 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-21 9:47 [PATCH v2 0/5] Boot RISC-V kernel from any 4KB aligned address Anup Patel
2019-03-21 9:47 ` [PATCH v2 1/5] RISC-V: Add separate defconfig for 32bit systems Anup Patel
2019-03-21 9:47 ` [PATCH v2 2/5] RISC-V: Make setup_vm() independent of GCC code model Anup Patel
2019-03-23 15:45 ` Mike Rapoport
2019-03-25 4:19 ` Anup Patel
2019-03-21 9:47 ` [PATCH v2 3/5] RISC-V: Allow booting kernel from any 4KB aligned address Anup Patel
2019-03-23 15:40 ` Mike Rapoport
2019-03-23 17:24 ` Christoph Hellwig [this message]
2019-03-24 4:16 ` Anup Patel
2019-03-24 3:32 ` Anup Patel
2019-03-21 9:47 ` [PATCH v2 4/5] RISC-V: Remove redundant trampoline page table Anup Patel
2019-03-22 13:33 ` Christoph Hellwig
2019-03-25 4:17 ` Anup Patel
2019-03-21 9:47 ` [PATCH v2 5/5] RISC-V: Fix memory reservation in setup_bootmem() Anup Patel
2019-03-22 13:31 ` Christoph Hellwig
2019-03-23 15:44 ` Mike Rapoport
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