From: Alexandre Ghiti <alexghiti@rivosinc.com>
To: Woody Zhang <woodylab@foxmail.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Conor Dooley <conor.dooley@microchip.com>,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] riscv: move memblock_allow_resize() after lm is ready
Date: Mon, 12 Jun 2023 09:15:38 +0200 [thread overview]
Message-ID: <CAHVXubiYHQCYkymde2y_okNb2XcE-xVBMj8iZ7kM5d08bhqxiQ@mail.gmail.com> (raw)
In-Reply-To: <tencent_D656D683705F41324657ED3393C3384C7408@qq.com>
Hi Woody,
On Sat, Jun 10, 2023 at 1:49 AM Woody Zhang <woodylab@foxmail.com> wrote:
>
> The initial memblock metadata is accessed from kernel image mapping. The
> regions arrays need to "reallocated" from memblock and accessed through
> linear mapping to cover more memblock regions. So the resizing should
> not be allowed until linear mapping is ready. Note that there are
> memblock allocations when building linear mapping.
>
> Signed-off-by: Woody Zhang <woodylab@foxmail.com>
> ---
> arch/riscv/mm/init.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> index 9e9da69720ce..8a33ecbb4d0f 100644
> --- a/arch/riscv/mm/init.c
> +++ b/arch/riscv/mm/init.c
> @@ -258,7 +258,6 @@ static void __init setup_bootmem(void)
> dma_contiguous_reserve(dma32_phys_limit);
> if (IS_ENABLED(CONFIG_64BIT))
> hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT);
> - memblock_allow_resize();
> }
>
> #ifdef CONFIG_MMU
> @@ -1250,6 +1249,9 @@ static void __init setup_vm_final(void)
> csr_write(CSR_SATP, PFN_DOWN(__pa_symbol(swapper_pg_dir)) | satp_mode);
> local_flush_tlb_all();
>
> + /* Depend on that Linear Mapping is ready */
> + memblock_allow_resize();
> +
> pt_ops_set_late();
> }
> #else
> --
> 2.39.2
>
The commit log does not describe the issue thoroughly enough to me,
maybe you could point to the arm64 commit that did the same? I mean
commit 24cc61d8cb5a ("arm64: memblock: don't permit memblock resizing
until linear mapping is up").
Another point is that I would not put this call into setup_vm_final(),
I'd rather add it in paging_init() as it does not seem like a good fit
for setup_vm_final(). But that's a nit so up to you of course.
Anyway, that's a good catch, thanks!
Alex
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next prev parent reply other threads:[~2023-06-12 7:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-09 23:43 [PATCH] riscv: move memblock_allow_resize() after lm is ready Woody Zhang
2023-06-10 15:44 ` Conor Dooley
2023-06-10 23:31 ` Woody Zhang
2023-06-11 10:15 ` Conor Dooley
2023-06-12 7:15 ` Alexandre Ghiti [this message]
2023-06-14 9:51 ` Song Shuai
2023-06-14 12:41 ` Woody Zhang
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