From: "Rong Zhang" <rongrong@oss.cipunited.com>
To: "Huacai Chen" <chenhuacai@kernel.org>,
"Jiaxun Yang" <jiaxun.yang@flygoat.com>,
"Thomas Bogendoerfer" <tsbogend@alpha.franken.de>
Cc: "Rong Zhang" <rongrong@oss.cipunited.com>, "Yao Zi" <me@ziyao.cc>,
<linux-mips@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
"Icenowy Zheng" <uwu@icenowy.me>, "Rong Zhang" <i@rong.moe>,
<stable@vger.kernel.org>
Subject: [PATCH v2] MIPS: Loongson64: env: Check UARTs passed by LEFI cautiously
Date: Mon, 16 Mar 2026 01:28:22 +0800 [thread overview]
Message-ID: <20260315172824.352412-1-rongrong@oss.cipunited.com> (raw)
In-Reply-To: <20260314211336.408561-1-rongrong@oss.cipunited.com>
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")
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
next prev parent reply other threads:[~2026-03-15 17:28 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 ` Rong Zhang [this message]
2026-03-17 10:58 ` [PATCH v2] " Jiaxun Yang
2026-04-01 20:28 ` Thomas Bogendoerfer
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