From: Atish Patra <atishp@atishpatra.org>
To: Heiko Stuebner <heiko@sntech.de>
Cc: Palmer Dabbelt <palmer@dabbelt.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Albert Ou <aou@eecs.berkeley.edu>,
linux-riscv <linux-riscv@lists.infradead.org>,
devicetree <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org List"
<linux-kernel@vger.kernel.org>, Rob Herring <robh+dt@kernel.org>,
Wei Fu <wefu@redhat.com>, liush <liush@allwinnertech.com>,
Guo Ren <guoren@kernel.org>, Anup Patel <anup@brainfault.org>,
Drew Fustini <drew@beagleboard.org>,
Christoph Hellwig <hch@lst.de>, Arnd Bergmann <arnd@arndb.de>,
Chen-Yu Tsai <wens@csie.org>, Maxime Ripard <maxime@cerno.tech>,
Greg Favor <gfavor@ventanamicro.com>,
Andrea Mondelli <andrea.mondelli@huawei.com>,
Jonathan Behrens <behrensj@mit.edu>,
Xinhaoqu <xinhaoqu@huawei.com>,
Bill Huffman <huffman@cadence.com>,
Nick Kossifidis <mick@ics.forth.gr>,
Allen Baum <allen.baum@esperantotech.com>,
Josh Scheid <jscheid@ventanamicro.com>,
Richard Trauben <rtrauben@gmail.com>,
Samuel Holland <samuel@sholland.org>,
Christoph Muellner <cmuellner@linux.com>,
Philipp Tomsich <philipp.tomsich@vrull.eu>
Subject: Re: [PATCH v6 01/14] riscv: prevent null-pointer dereference with sbi_remote_fence_i
Date: Thu, 10 Feb 2022 17:59:18 -0800 [thread overview]
Message-ID: <CAOnJCUL6b=2dMJfJFTUj-3gshHGMYpgQEc0XUeSbkC4g7ayJkQ@mail.gmail.com> (raw)
In-Reply-To: <20220209123800.269774-2-heiko@sntech.de>
On Wed, Feb 9, 2022 at 4:38 AM Heiko Stuebner <heiko@sntech.de> wrote:
>
> The callback used inside sbi_remote_fence_i is set at sbi probe time
> to the needed variant. Before that it is a NULL pointer.
>
> Some users like the flush_icache_*() functions suggest a generic
> functionality, that doesn't depend on a specific boot-stage but
> uses sbi_remote_fence_i as one option to flush other cpu cores.
>
> So they definitly shouldn't run into null-pointer dereference
/s/definitly/definitely
> issues when called "too early" during boot.
>
> So introduce an empty function to be the standard for the __sbi_rfence
> function pointer until sbi_init has run.
>
> Users of sbi_remote_fence_i will have separate code for the local
> cpu and sbi_init() is called before other cpus are brought up.
> So there are no other cpus present at the time when the issue
> might happen.
>
> Signed-off-by: Heiko Stuebner <heiko@sntech.de>
> ---
> arch/riscv/kernel/sbi.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
> index f72527fcb347..c839acd668d3 100644
> --- a/arch/riscv/kernel/sbi.c
> +++ b/arch/riscv/kernel/sbi.c
> @@ -15,11 +15,19 @@
> unsigned long sbi_spec_version __ro_after_init = SBI_SPEC_VERSION_DEFAULT;
> EXPORT_SYMBOL(sbi_spec_version);
>
> +static int __sbi_rfence_none(int fid, const struct cpumask *cpu_mask,
> + unsigned long start, unsigned long size,
> + unsigned long arg4, unsigned long arg5)
> +{
> + return -EOPNOTSUPP;
> +}
> +
> static void (*__sbi_set_timer)(uint64_t stime) __ro_after_init;
> static int (*__sbi_send_ipi)(const struct cpumask *cpu_mask) __ro_after_init;
> static int (*__sbi_rfence)(int fid, const struct cpumask *cpu_mask,
> unsigned long start, unsigned long size,
> - unsigned long arg4, unsigned long arg5) __ro_after_init;
> + unsigned long arg4, unsigned long arg5)
> + __ro_after_init = __sbi_rfence_none;
>
> struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
> unsigned long arg1, unsigned long arg2,
> --
> 2.30.2
>
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
Otherwise, LGTM.
Reviewed-by: Atish Patra <atishp@rivosinc.com>
--
Regards,
Atish
next prev parent reply other threads:[~2022-02-11 1:59 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-09 12:37 [PATCH v6 00/14] riscv: support for Svpbmt and D1 memory types Heiko Stuebner
2022-02-09 12:37 ` [PATCH v6 01/14] riscv: prevent null-pointer dereference with sbi_remote_fence_i Heiko Stuebner
2022-02-11 1:59 ` Atish Patra [this message]
2022-02-09 12:37 ` [PATCH v6 02/14] riscv: integrate alternatives better into the main architecture Heiko Stuebner
2022-02-09 12:37 ` [PATCH v6 03/14] riscv: allow different stages with alternatives Heiko Stuebner
2022-02-09 12:37 ` [PATCH v6 04/14] riscv: implement module alternatives Heiko Stuebner
2022-02-09 12:37 ` [PATCH v6 05/14] riscv: implement ALTERNATIVE_2 macro Heiko Stuebner
2022-02-09 12:37 ` [PATCH v6 06/14] riscv: extend concatenated alternatives-lines to the same length Heiko Stuebner
2022-02-09 12:37 ` [PATCH v6 07/14] riscv: prevent compressed instructions in alternatives Heiko Stuebner
2022-03-08 0:47 ` Palmer Dabbelt
2022-02-09 12:37 ` [PATCH v6 08/14] riscv: move boot alternatives to a slightly earlier position Heiko Stuebner
2022-02-10 22:42 ` Atish Patra
2022-02-11 1:11 ` Heiko Stübner
2022-02-11 1:57 ` Atish Patra
2022-02-11 9:34 ` Heiko Stübner
2022-03-08 0:47 ` Palmer Dabbelt
2022-03-23 16:51 ` Heiko Stübner
2022-02-09 12:37 ` [PATCH v6 09/14] riscv: Fix accessing pfn bits in PTEs for non-32bit variants Heiko Stuebner
2022-02-09 12:37 ` [PATCH v6 10/14] riscv: add cpufeature handling via alternatives Heiko Stuebner
2022-02-09 12:37 ` [PATCH v6 11/14] dt-bindings: riscv: add MMU Standard Extensions support for Svpbmt Heiko Stuebner
2022-02-09 18:47 ` Rob Herring
2022-02-09 12:37 ` [PATCH v6 12/14] riscv: add RISC-V Svpbmt extension support Heiko Stuebner
2022-02-09 12:37 ` [PATCH v6 13/14] riscv: remove FIXMAP_PAGE_IO and fall back to its default value Heiko Stuebner
2022-02-09 12:38 ` [PATCH v6 14/14] riscv: add memory-type errata for T-Head Heiko Stuebner
2022-02-11 0:12 ` Atish Patra
2022-02-11 9:25 ` Heiko Stübner
2022-02-12 0:27 ` Atish Patra
2022-02-11 2:01 ` Atish Patra
2022-02-14 3:42 ` Samuel Holland
2022-02-09 17:49 ` [PATCH v6 00/14] riscv: support for Svpbmt and D1 memory types Jisheng Zhang
2022-02-09 23:44 ` Heiko Stübner
2022-02-10 16:01 ` Jisheng Zhang
2022-02-11 0:25 ` Atish Patra
2022-02-11 1:48 ` Atish Patra
2022-02-11 2:04 ` Heiko Stübner
2022-02-12 0:25 ` Atish Patra
2022-02-14 20:02 ` Heiko Stübner
2022-02-14 20:25 ` Atish Patra
2022-02-14 20:37 ` Heiko Stübner
2022-03-09 7:56 ` Guo Ren
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