From: "Jiaxun Yang" <jiaxun.yang@flygoat.com>
To: "Rong Zhang" <rongrong@oss.cipunited.com>,
"Huacai Chen" <chenhuacai@kernel.org>,
"Thomas Bogendoerfer" <tsbogend@alpha.franken.de>
Cc: "Yao Zi" <me@ziyao.cc>,
"linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>,
linux-kernel@vger.kernel.org, "Icenowy Zheng" <uwu@icenowy.me>,
"Rong Zhang" <i@rong.moe>,
"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH v2] MIPS: Loongson64: env: Check UARTs passed by LEFI cautiously
Date: Tue, 17 Mar 2026 10:58:37 +0000 [thread overview]
Message-ID: <55f5355f-3dc0-4ae8-812a-0eb07dcc25e6@app.fastmail.com> (raw)
In-Reply-To: <20260315172824.352412-1-rongrong@oss.cipunited.com>
On Sun, 15 Mar 2026, at 5:28 PM, Rong Zhang wrote:
> Some firmware does not set nr_uarts properly and passes empty items.
> Iterate at most min(system->nr_uarts, MAX_UARTS) items to prevent
> out-of-bounds access, and ignore UARTs with addr 0 silently.
>
> Meanwhile, our DT only works with UPIO_MEM but theoretically firmware
> may pass other IO types, so explicitly check against that.
>
> Tested on Loongson-LS3A4000-7A1000-NUC-SE.
>
> Fixes: 3989ed418483 ("MIPS: Loongson64: env: Fixup serial
> clock-frequency when using LEFI")
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Sign, firmwares are always insane like this :-(
> Cc: stable@vger.kernel.org
> Reviewed-by: Yao Zi <me@ziyao.cc>
> Signed-off-by: Rong Zhang <rongrong@oss.cipunited.com>
> ---
> Changes in v2:
> - Sort new includes alphabetically (thanks Yao Zi)
> ---
> arch/mips/loongson64/env.c | 18 +++++++++++++++++-
> 1 file changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/arch/mips/loongson64/env.c b/arch/mips/loongson64/env.c
> index 11ddf02d6a15..7abcca7ab4ed 100644
> --- a/arch/mips/loongson64/env.c
> +++ b/arch/mips/loongson64/env.c
> @@ -17,7 +17,9 @@
> #include <linux/dma-map-ops.h>
> #include <linux/export.h>
> #include <linux/libfdt.h>
> +#include <linux/minmax.h>
> #include <linux/pci_ids.h>
> +#include <linux/serial_core.h>
> #include <linux/string_choices.h>
> #include <asm/bootinfo.h>
> #include <loongson.h>
> @@ -106,9 +108,23 @@ static void __init lefi_fixup_fdt(struct
> system_loongson *system)
>
> is_loongson64g = (read_c0_prid() & PRID_IMP_MASK) == PRID_IMP_LOONGSON_64G;
>
> - for (i = 0; i < system->nr_uarts; i++) {
> + for (i = 0; i < min(system->nr_uarts, MAX_UARTS); i++) {
> uartdev = &system->uarts[i];
>
> + /*
> + * Some firmware does not set nr_uarts properly and passes empty
> + * items. Ignore them silently.
> + */
> + if (uartdev->uart_base == 0)
> + continue;
> +
> + /* Our DT only works with UPIO_MEM. */
> + if (uartdev->iotype != UPIO_MEM) {
> + pr_warn("Ignore UART 0x%llx with iotype %u passed by firmware\n",
> + uartdev->uart_base, uartdev->iotype);
> + continue;
> + }
> +
> ret = lefi_fixup_fdt_serial(fdt_buf, uartdev->uart_base,
> uartdev->uartclk);
> /*
>
> base-commit: 267594792a71018788af69e836c52e34bb8054af
> --
> 2.53.0
--
- Jiaxun
next prev parent reply other threads:[~2026-03-17 10:58 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-14 21:13 [PATCH] MIPS: Loongson64: env: Check UARTs passed by LEFI cautiously Rong Zhang
2026-03-15 11:41 ` Yao Zi
2026-03-15 17:28 ` [PATCH v2] " Rong Zhang
2026-03-17 10:58 ` Jiaxun Yang [this message]
2026-04-01 20:28 ` Thomas Bogendoerfer
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